Academic literature on the topic 'Escherichia-Shigella'
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Journal articles on the topic "Escherichia-Shigella":
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Ferdi, Roni, Irsan Saleh, Theodorus Theodorus, and Salni Salni. "Uji Efek Antibakteri Propolis Terhadap Escherichia Coli Dan Shigella Dysenteriae Secara In Vitro." Biomedical Journal of Indonesia: Jurnal Biomedik Fakultas Kedokteran Universitas Sriwijaya 5, no. 2 (May 31, 2019): 52–61. http://dx.doi.org/10.32539/bji.v5i1.7982.
Abstract:
Bakteri yang sering menjadi penyebab diare infeksi adalah Escherichia coli dan Shigella dysenteriae. Penggunaan antibiotik yang berlebihan dan kurang rasional pada kasus diare mendorong terjadinya perkembangan resistensi patogen multi obat. Propolis merupakan salah satu solusi untuk mengatasi infeksi diare. Tujuan penelitian ini untuk mengetahui kemampuan efek antibakteri ekstrak propolis terhadap bakteri Escherichia coli dan Shigella dysenteriae dalam pengujian secara in vitro dengan berbagai konsentrasi. Penelitian eksperimen laboratorium secara in vitro. Sampel dalam penelitian ini adalah bakteri Escherichia coli dan Shigella dysenteriae dengan tahapan penelitian dimulai dari proses ekstraksi dilakukan dengan menggunakan metode ekstraksi bertingkat. Hasil penelitian menunjukkan konsentrasi fraksi n-heksan terkecil yang masih menghambat pertumbuhan bakteri Escherichia coli dan Shigella dysenteriae adalah 250 µg/ml dan konsentrasi ini dinyatakan sebagai nilai KHM. Uji kesetaraan konsentrasi 250 µg/ml fraksi n-heksan propolis setara dengan 4,0 µg/ml ciprofloxacin terhadap Escherichia coli dan setara dengan 4,6 µg/ml ciprofloxacin terhadap Shigella dysenteriae, sedangkan uji kesetaraan konsentrasi 250 µg/ml fraksi etil asetat propolis setara dengan 5,2 µg/ml ciprofloxacin terhadap Escherichia coli dan setara dengan 4,5 µg/ml ciprofloxacin terhadap Shigella dysenteriae. Kesimpulan penelitian ini adalah Ekstrak n-heksan dan etil asetat propolis memiliki efektifitas antibakteri terhadap Escherichia coli dan Shigella dysenteriae. Fraksi n-heksan dan etil asetat propolis memiliki aktivitas antibakteri yang lebih rendah jika dibandingkan dengan ciprofloxacin dalam menghambat pertumbuhan bakteri Escherichia coli dan Shigella dysenteriae. Senyawa antibakteri yang terdapat dalam fraksi n-heksan dan etil asetat propolis adalah flavonoid dan fenol.
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Novalina, Dhiah, Sugiyarto Sugiyarto, and Ari Susilowati. "Aktivitas Antibakteri Kulit Buah Karika Dieng terhadap Shigella flexneri dan Escherichia coli." Jurnal Teknologi Laboratorium 7, no. 2 (December 31, 2018): 53–60. http://dx.doi.org/10.29238/teknolabjournal.v7i2.137.
Abstract:
Karika merupakan tanaman endemik Dataran Tinggi Dieng. Daun Karika telah diteliti memiliki aktivitas antibakteri terhadap bakteri penyebab diare, sedangkan kulit buah dibuang atau dijadikan campuran pakan ternak. Penelitian ini bertujuan untuk mengetahui aktivitas antibakteri kulit buah Karika terhadap bakteri penyebab keracunan, Shigella flexneri dan Escherichia coli. Sampel difraksinasi untuk memperoleh fraksi n-heksan dan etil asetat. Fraksi diuji aktivitas antibakteri nya terhadap bakteri Shigella flexneri dan Escherichia coli dengan metode sumuran. Hasil penelitian menunjukkan bahwa fraksi etil asetat dengan konsentrasi 50% memiliki daya hambat tertinggi terhadap Shigella flexneri dan Escherichia coli dibandingkan dengan konsentrasi lainnya. Berdasarkan hasil penelitian disimpulkan bahwa kulit buah Karika memiliki aktivitas antibakteri terhadap bakteri Shigella flexneri dan Escherichia coli.
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Siregar, Beladiena Citra, Welly Darwis, and Mardhatillah Sariyanti. "Uji Efektivitas Ekstrak Akar Tanaman Lauh Putiah (Ficus racemosa L.) Terhadap Bakteri Escherichia coli dan Shigella dysenteriae Penyebab Diare." Jurnal Kedokteran RAFLESIA 5, no. 1 (October 31, 2019): 53–63. http://dx.doi.org/10.33369/juke.v5i1.8778.
Abstract:
ABSTRAKLatar Belakang: Diare merupakan salah satu masalah kesehatan di dunia dan negara berkembang. Mortalitas diare berkisar 17,5-21% dengan ekuivalent 1,5 juta orang setiap tahunnya. Escherichia coli dan Shigella Sp. merupakan patogen utama penyebab diare. Antibioik siprofloksasin yang digunakan untuk mengobati diare memiliki berbagai efek samping. Pemanfaatan tanaman obat merupakan salah satu alternatif untuk mengatasi masalah tersebut. Akar Lauh Putiah merupakan salah satu tanaman obat tradisional yang mempunyai banyak manfaat, salah satunya sebagai antibakteri. Penggunaan akar pada masyarakat Desa Pasar Pino dengan cara meminum air rebusan dari akar Lauh Putiah. Kebiasaan dan pengetahuan tersebut telah secara turun-temurun, namun belum dilatarbelakangi studi ilmiah.Metode: Ekstraksi akar Lauh Putiah dilakukan dengan metode maserasi menggunakan pelarut etanol 96% dan dilarutkan dengan DMSO. Hasil ekstraksi kemudian dilakukan Uji Minimal Inhibitory Concentration (MIC). Setelah dilakukan uji MIC kemudian dilakukan pengujian efektivitas. Kedua uji ini menggunakan metode difusi kertas cakram. Parameter yang digunakan ialah besarnya zona hambat yang terbentuk disekitar kertas cakram, dan kontrol positif yang digunakan adalah larutan antibiotik siprofloksasin 50 µg/ml untuk bakteri Escherichia coli dan bakteri Shigella dysenteriae.Hasil: Hasil pengujian MIC didapatkan bahwa ekstrak akar Lauh Putiah memiliki kemampuan sebagai antibakteri terhadap bakteri Esherichia coli dan Shigella dysentriae. Dari analisis statistik pengujian ANOVA pengaruh ekstrak akar Lauh Putiah menghambat bakteri Escherichia coli dan Shigella sysentriae memiliki nilai Fhitung > Ftabel dengan nilai ? = 0,05 dan kemudian diuji lanjut dengan menggunakan uji Duncan dan didapatkan zona hambat yang efektif konsentrasi yang efektif dalam menghambat pertumbuhan bakteri Escherichia coli adalah konsentrasi 60% (AE3). Pada bakteri Shigella dysentriae didapatkan konsentrasi yang efektif dalam menghambat pertumbuhan bakteri Shigella dysenteriae adalah konsentrasi 87,5% (BE4).Kesimpulan: Ekstrak Akar Tanaman Lauh Putiah (Ficus racemosa L.) memiliki daya hambat terhadap pertumbuhan bakteri Escherichia coli dan Shigella dysentriae. Kata kunci: Escherichia coli, Shigella dysenteriae, Lauh Putiah, Ficus racemosa Linn. ABSTRACTBackground: Diarrhea is one of health problems in the world and developing countries. Diarrhea mortality range is 17.5-21% with an equivalent of 1.5 million people per year. Escherichia coli and Shigella sp. are the main pathogen bacteria that causes diarrhea. Ciprofloxacin is common antibiotic that used to treat diarrhea, but it has various side effects. The use of medicinal plants is an alternative to overcome this problem. Lauh Putiah roots is one of the traditional medicinal plants that has many benefits, one of the benefits is to produce antibacterial compounds. Lauh Putiah roots is used as a medicine for people in Pasar Pino village, it used to heal diarrhea by drinking boiled water from Lauh Putiah roots. These habits have been passed down through generations, but it has not been proofed by scientific studies.Methods: Extraction of Lauh Putiah root was done by maceration method using ethanol 96% and dissolved with DMSO. The extraction results were used to Minimal Inhibitory Concentration (MIC) assay. After MIC assay, effectiveness assay was done. Both of these assay used paper disk diffusion methods. The parameters that used were the amount of inhibition zone formed around the disc paper, and the positive control used ciprofloxacin antibiotic 50 µg/ml for Escherichia coli and Shigella sp.Results: The MIC assay results showed that the roots extract of Lauh Putiah had the ability as an antibacterial against Esherichia coli and Shigella dysentriae. From the statistical analysis of ANOVA test, the effect of Lauh Putiah root extract inhibits Escherichia coli and Shigella sysentriae with a value of Fcount> Ftable with a value of ? = 0.05 and then further tested using Duncan test and found an effective inhibition zone concentration that inhibits growth of Escherichia coli in 60% concentration (AE3) and inhibits growth of Shigella dysentriae in 87.5% concentration (BE4).Conclusion: Lauh Putiah Root Extract (Ficus racemosa L.) has inhibitory effect on the growth of Escherichia coli and Shigella dysentriae. Keywords: Escherichia coli, Shigella dysenteriae, Lauh Putiah, Ficus racemosa Linn.
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Dewi, Lulu Fatma, Sartini Sartini, and Rahmiati Rahmiati. "Isolasi Bakteri Asam Laktat dari Usus Sapi (Bos taurus) serta Kemampuannya dalam Menghambat Pertumbuhan Bakteri Eschericia coli dan Shigella sp." Jurnal Ilmiah Biologi UMA (JIBIOMA) 1, no. 1 (May 5, 2019): 21–27. http://dx.doi.org/10.31289/jibioma.v1i1.145.
Abstract:
The purpose of this research was to determine the ability of BAL from cattle intestine (Bos taurus) in inhibiting the growth of Eschericia coli and Shigella sp. Testing of BAL capability in inhibiting growth of Escherichia coli and Shigella sp. using the disc-diffusion method or the Kirby-Bauer method, which was done by measuring the inhibit zone around the paper disc. Data were analyzed descriptively by displaying data in table and picture form. The results obtained 2 isolates of BAL from the cow intestine. All isolates showed positive results when tested for antibacterial against Escherichia coli and Shigella sp. In isolate BAL with code sp1 has inhibition zone against Escherichia coli equal to 7.5 mm and to Shigella sp. of 6.8 mm, whereas in isolate BAL with code sp2 has inhibition zone against Escherichia coli equal to 8.9 mm and to Shigella sp. of 8.0 mm. Based on the results obtained, it can be concluded that isolates of lactic acid bacteria with sp2 code has inhibition zone 8.9 mm in inhibiting Eschericia coli while against bacteria Shigella sp. has a diameter of 8.0 mm.
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Denita, Alvina Via, Ainur Rofieq, H. Husamah, and Abdulkadir Rahardjanto. "Analysis of Bacteria Escherichia coli, Salmonella sp and Shigella sp on Black Sticky Rice Ice in Malang." Mangifera Edu 6, no. 2 (January 31, 2022): 169–81. http://dx.doi.org/10.31943/mangiferaedu.v6i2.129.
Abstract:
Es tape ketan hitam is a traditional drink that is in great demand by the public and has the potential as a source of disease transmission is in the process of processing not using proper hygiene sanitation. The purpose of this research is to determine the content of Escherichia coli, Salmonella sp., and Shigella sp. in es tape ketan hitam. The research was conducted by planting Escherichia coli on EMBA and planting Salmonella sp., and Shigella sp. on SSA. The technique used is the spread method. The results of this study indicate that samples 1, 2, 5 and, 6 contain Escherichia coli exceeding the threshold. Samples 1, 5 and, 6 contained Salmonella sp., and Shigella sp. exceed the provisions. Microbiological requirements of drinks based on PerBPOM RI No. 13 of 2019 is the maximum total Escherichia coli, which is < 3 colonies/ml and 0 colonies/25ml (negative) for Salmonella sp., and Shigella sp. So it can be concluded that 4 out of 6 samples of es tape ketan hitam in Malang City do not meet the criteria for a drink that is fit for consumption based on PerBPOM RI No. 13 of 2019.
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Suwandi, Edy. "Pengaruh Air Rebusan Rimpang Jeringau Merah (Acorus Calamus L.) Konsentrasi 100%, 75%, 50%, Dan 25% terhadap Sensitifitas Bakteri Escherichia Coli, Salmonella Typhi dan Shigella sp." Jurnal Laboratorium Khatulistiwa 2, no. 2 (July 7, 2019): 81. http://dx.doi.org/10.30602/jlk.v2i2.327.
Abstract:
Abstract: Red Jeringau (Acorus calamus L.) is one of the endemic plants of West Kalimantan which contains antibacterial, phytochemical, and antioxidant activity. This plant has been used for generations by people who live in the interior and away from health services as a mixture of traditional medicines. This study aims to determine the effect of the concentration of Jeringau Red rhizome water on the sensitivity of Escherichia coli, Salmonella typhi and Shigella sp with concentrations of 100%, 75%, 50%, and 25%. The Red Jeringau Rhizome is obtained from the Landak Regency and then boiled using distilled water. This study uses a quasi-experimental design with sampling techniques using purposive sampling. This study was conducted with 6 replications for each treatment. The effectiveness test of the Red Jeringau rhizome boiled water was carried out using the Kirby Bauer method with bacterial suspension which was adjusted to Mc Farland’s turbidity standard. The data obtained were then analyzed using a simple linear regression test and obtained p (0.00) <α (0.05) against the bacteria Escherichia coli, Salmonella typhi, and Shigella sp. This means that H1 is accepted so that it can be stated that there is an influence of the concentration of Jeringau Red rhizome water on Escherichia coli, Salmonella typhi, and Shigella sp. The magnitude of the contribution effect of Jeringau Red rhizome on bacterial sensitivity is 85.7% (R = 0.857) in Escherichia coli, 91.1% (R = 0.911) in Salmonella typhi, and 85.7% (R = 0.857) in Shigella sp.Abstrak Jeringau Merah (Acorus calamus L.) merupakan salah satu tanaman endemik Kalimantan Barat yang mengandung antibakteri, ftokimia, dan aktivitas antioksidan. Tumbuhan ini secara turun temurun dimanfaatkan masyarakat yang tinggal dipedalaman dan jauh dari pelayanan kesehatan sebagai ramuan obat tradisional.Penelitian ini bertujuan mengetahui pengaruh konsentrasi air rebusan rimpang Jeringau Merah terhadap sensitiftas bakteri Escherichia coli, Salmonella typi dan Shigella sp dengan konsentrasi 100%, 75%, 50% dan 25%. Rimpang Jeringau Merah diperoleh dari Kabupaten Landak kemudian direbus menggunakan aquadest. Penelitian ini menggunakan desain eksperimen semu (Quasi Experiment) dengan teknik pengmbilan sampel dengan cara purposive sampling. Penelitian ini dilakukan dengan 6 replikasi untuk masing-masing perlakuan. Uji efektiftas air rebusan rimpang Jeringau Merah dilakukan menggunakan metode Kirby Bauer dengan suspensi bakteri yang disesuaikan dengan standar kekeruhan Mc Farland. Data yang diperoleh kemudian dianalisis menggunakan uji regresi linear sederhana dan didapatkan p (0,00) < α (0,05) terhadap bakteri Escherichia coli, Salmonella typhi, dan Shigella sp. Hal ini berarti H1 diterima sehingga dapat dinyatakan bahwa terdapat pengaruh konsentrasi air rebusan rimpang Jeringau Merah terhadap bakteri Escherichia coli, Salmonella typhi, dan Shigella sp. Besarnya kontribusi pengaruh rebusan rimpang Jeringau Merah terhadap sensitiftas bakteri yaitu 85,7% (R=0,857) pada Escherichia coli, 91,1% (R=0,911) pada Salmonella typhi, dan 85,7% (R=0,857) pada Shigella sp.
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Azmuda, Nafisa, Rabeya Bilkis, Humaira Akter, Anowara Begum, Sirajul Islam Khan, and Nils Kåre Birkeland. "Serological cross-reactivity of environmental Escherichia coli strains with Shigella-specific antisera." Bangladesh Journal of Microbiology 33, no. 1-2 (December 31, 2018): 29–33. http://dx.doi.org/10.3329/bjm.v33i1.39600.
Abstract:
Many bacteria of clinical and environmental origin show evidence of sharing common surface antigens. The present study aimed for isolation of Escherichia coli strains that were serologically cross-reactive with Shigella species from freshwater ecosystems in Bangladesh by conventional cultural methods. Among twenty eight isolates, two isolates, termed 12(35) and 6(50) showed cross-reactivity with four polyvalent serogroup-specific Shigella antisera using slide agglutination assay. The isolates were identified and charcterized by cultural and biochemical properties and Western blot analysis. The isolates showed typical Escherichia coli cell morphology and cultural and biochemical properties and were identified as Escherichia coli by API 20E tests. Western blot analysis confirmed the isolates as cross-reactive with all the four group-specific Shigella antisera due to presence of immunogenic proteins and LPS. One of the isolates also showed cross-reactivity with multiple type-specific Shigella boydii antisera (monovalent) because of immunogenic proteins. Both the isolates were identified as nonpathogenic due to absence of virulence marker genes of diarrheagenic E. coli variants.This study revealed that a number of bacteria present in the environment could share important Shigella species surface antigens. Naturally occurring nonpathogenic environmental bacteria expressing surface antigens specific for certain types of Shigella could be a good choice for vaccine candidates against shigellosis.
Bangladesh J Microbiol, Volume 33, Number 1-2, June-Dec 2016, pp 29-33
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Nguyen, Trung Vu, Phung Van Le, Chinh Huy Le, and Andrej Weintraub. "Antibiotic Resistance in Diarrheagenic Escherichia coli and Shigella Strains Isolated from Children in Hanoi, Vietnam." Antimicrobial Agents and Chemotherapy 49, no. 2 (February 2005): 816–19. http://dx.doi.org/10.1128/aac.49.2.816-819.2005.
Abstract:
ABSTRACT The MICs for 162 diarrheagenic Escherichia coli strains and 28 Shigella strains were determined on the basis of NCCLS guidelines. More than 75% of the strains were resistant to ampicillin, chloramphenicol (53.6% of Shigella strains), and trimethoprim-sulfamethoxazole. Multiresistance was detected in 89.5% of E. coli strains and 78.6% of Shigella strains.
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Hyma, Katie E., David W. Lacher, Adam M. Nelson, Alyssa C. Bumbaugh, J. Michael Janda, Nancy A. Strockbine, Vincent B. Young, and Thomas S. Whittam. "Evolutionary Genetics of a New Pathogenic Escherichia Species: Escherichiaalbertii and Related Shigellaboydii Strains." Journal of Bacteriology 187, no. 2 (January 15, 2005): 619–28. http://dx.doi.org/10.1128/jb.187.2.619-628.2005.
Abstract:
ABSTRACT A bacterium originally described as Hafnia alvei induces diarrhea in rabbits and causes epithelial damage similar to the attachment and effacement associated with enteropathogenic Escherichia coli. Subsequent studies identified similar H. alvei-like strains that are positive for an intimin gene (eae) probe and, based on DNA relatedness, are classified as a distinct Escherichia species, Escherichia albertii. We determined sequences for multiple housekeeping genes in five E. albertii strains and compared these sequences to those of strains representing the major groups of pathogenic E. coli and Shigella. A comparison of 2,484 codon positions in 14 genes revealed that E. albertii strains differ, on average, at ∼7.4% of the nucleotide sites from pathogenic E. coli strains and at 15.7% from Salmonella enterica serotype Typhimurium. Interestingly, E. albertii strains were found to be closely related to strains of Shigella boydii serotype 13 (Shigella B13), a distant relative of E. coli representing a divergent lineage in the genus Escherichia. Analysis of homologues of intimin (eae) revealed that the central conserved domains are similar in E. albertii and Shigella B13 and distinct from those of eae variants found in pathogenic E. coli. Sequence analysis of the cytolethal distending toxin gene cluster (cdt) also disclosed three allelic groups corresponding to E. albertii, Shigella B13, and a nontypeable isolate serologically related to S. boydii serotype 7. Based on the synonymous substitution rate, the E. albertii-Shigella B13 lineage is estimated to have split from an E. coli-like ancestor ∼28 million years ago and formed a distinct evolutionary branch of enteric pathogens that has radiated into groups with distinct virulence properties.
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Amos, Dora, Priya Khanna, Sayeed Adnan Aali, and Guduru Gopal Rao. "Is whole genome sequencing the answer for identifying Shigella bacteraemia?" BMJ Case Reports 12, no. 12 (December 2019): e231596. http://dx.doi.org/10.1136/bcr-2019-231596.
Abstract:
We present a rare case of Shigella flexneri bacteraemia and the challenges of differentiating Escherichia coli and Shigella spp using conventional and newer laboratory techniques in diagnostic laboratories. The organism was identified only after whole genomic sequencing .
Dissertations / Theses on the topic "Escherichia-Shigella":
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Blanchard, Geneviève. "Versatilité nutritionnelle de l'espèce génomique "Escherichia Coli-Shigella"." Paris 5, 1990. http://www.theses.fr/1990PA05P055.
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Albuquerque, José Antonio Tavares de. "Análise comparativa da transcrição de genes envolvidos na invasão e escape de \'Escherichia coli\' enteroinvasora e \'Shigella flexneri\' em macrófagos J774." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-17102006-094359/.
Abstract:
Escherichia coli enteroinvasora (EIEC) possuem características bioquímicas e genéticas semelhantes às de Shigella, porém para que ocorra um processo infeccioso são necessárias 102 células de Shigella em relação a 106 células de EIEC. A patogenicidade de Shigella e EIEC se dá pela presença de um plasmídio de virulência denominado pInv, que contêm os genes necessários para a invasão e disseminação bacteriana nas células do hospedeiro. Estudos anteriores relataram que os genes ipaA, ipaB, ipaC e ipaD de EIEC e Shigella não possuem diferenças genéticas que possam explicar sua diferença de patogenicidade. No presente trabalho, foram avaliados os níveis transcricionais dos genes envolvidos na invasão e disseminação dessas bactérias. Pela técnica de RT-PCR semi-quantitativo, pode-se observar diferenças nos níveis de transcrição para a maioria dos genes de virulência selecionados, quando as bactérias estavam em contato com os macrófagos. Porém, sem o contato com estas células, o nível de transcrição dos genes foi o mesmo entre as espécies, com exceção do gene ipaD. Foi verificada que a transcrição deste gene em contato com macrófago é praticamente a mesma entre as bactérias, enquanto que na ausência de macrófagos, o nível de transcrição é bem menor em EIEC, quando comparado no mesmo intervalo de tempo. Após estes resultados foram selecionados os principais genes para estudo por PCR em tempo real. Foi possível observar que o nível de transcrição de EIEC é menor, em relação a Shigella. Mais ainda, a análise dos genes dentro do mesmo operon mostrou uma cinética de transcrição distinta do icsB em relação a outros genes do operon das ipas. Os resultados obtidos sugerem que esta diferença de transcrição possa estar relacionada com a virulência mais branda em EIEC. Ainda mais, Os genes pertencentes ao operon icsB-ipaCB parecem ser regulados de forma distinta. Além disso, a transcrição de ipaD em EIEC, provavelmente, depende de uma via de sinalização distinta de Shigella flexneri. Diante desses resultados, novos estudos estão sendo propostos em nosso laboratório para melhor compreensão do mecanismo de virulência desse enteropatógeno.Enteroinvasive Escherichia coli (EIEC) serotypes described so far share antigenic, biochemical, genetic and pathogenetic properties with Shigella sp. However, in order for an infectious process to occur, an inoculum of 102 Shigella cells is needed in contrast to as much as 106 EIEC cells. The characteristic ability of S. flexneri and EIEC to enter epithelial cells, multiply intracellularly and spread from cell to cell is uniquely encoded by their 220-kb virulence plasmid. Previous studies realized in our laboratory showed that the genes ipaA, ipaB, ipaC and ipaD do not possess molecular alterations in the nucleotides sequences that can explain the difference in the pathogenicity between EIEC and Shigella spp. In the present work, the transcription levels of the bacterial genes involved in the invasion and escape from host cells were evaluated. Through reverse transcription-polymerase chain reaction (RT-PCR) analysis, differences in the transcription levels for the majority selected virulence genes could be observed when bacteria were in contact with the macrophages. However, without the contact with those cells, the transcription levels of the genes were the same between both bacteria species, with the exception of ipaD. When the bacteria is in contact with macrophages, the transcription of ipaD is the same in both species whereas in the absence of macrophages, the transcription level is lower in EIEC than Shigella, when compared in the same period of time. Those results provided the selection of the genes for the real time PCR analysis. In general, the EIEC transcription levels genes are lower than Shigella. More still, the icsB showed a distinct kinetic of transcription from the others genes in the same operon. All results suggest that the lower pathogenicity due to EIEC can partially have to the differences of the virulence genes transcription. Still more, the genes-encoded by operon icsB-ipaCB seem to be regulated of a distinct form. Therefore, transcription of the ipaD in EIEC probably depends on distinct signaling way of S. flexneri. New studies shows to be necessary for the better understanding of the pathogenic mechanism of EIEC.
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Pehrson, Moysés Estevão de Souza Freitas. "Avaliação da atividade antimicrobiana de substâncias sintetizadas por cepas de Lactobacillus sp. que apresentam propriedades probióticas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/97/97132/tde-14092016-163724/.
Abstract:
As infecções causadas por patógenos intestinais gram-negativos são importantes fontes de prejuízos na criação de animais domésticos como bovinos, ovinos, suínos e aves. Em muitos casos, opta-se pela administração de antibióticos de amplo espectro para prevenção destas infecções e atenuação das perdas. No entanto, esta prática apresenta risco para a saúde humana, bem como contribui para seleção de cepas resistentes. Nos últimos anos, muito tem se discutido a respeito de novas alternativas para atenuar os prejuízos mencionados sem apresentar o mesmo risco. Uma destas alternativas é a utilização de micro-organismos que apresentam propriedades probióticas que sintetizam substâncias inibitórias sobre espécies de patógenos intestinais. Esta abordagem praticamente elimina o risco de desenvolvimento de resistência aos antibióticos de uso clínico, além de evitar a presença de resíduos nos produtos de origem animal. O termo \"probiótico\" é utilizado atualmente para definir micro-organismos que, administrados em doses e frequências adequadas, conferem benefícios à saúde do hospedeiro. Nos últimos anos, diversos estudos têm sido desenvolvidos envolvendo quatro cepas de Lactobacillus (L. acidophilus ATCC 4356, L. casei ATCC 7469, L. fermentum ATCC 9338 e L. plantarum ATCC 8014) com resultados promissores no tocante às suas características probióticas. Desta forma, a proposta deste estudo foi avaliar a capacidade destas cepas em relação à produção de substâncias que apresentam atividade inibitória sobre espécies patogênicas, intestinais gram-negativas, especificamente Escherichia coli 0112, Escherichia coli 0124, Escherichia coli 0127, Shigella sonnei ATCC 25931, Shigella dysenteriae ATCC 13313, Salmonella enteritidis ATCC 13076. Para tanto, foi avaliada a atividade inibitória de substâncias presentes no sobrenadante livre de células de cada cepa. Adicionalmente, foi realizada a caracterização presuntiva das substâncias responsáveis pela inibição do crescimento microbiano quando os respectivos sobrenadantes foram submetidos a diferentes tratamentos (catalase, enzimas proteolíticas, tratamento térmico e neutralização do pH). A estratégia adotada consistiu na avaliação do crescimento, determinado por turbidimetria, das cepas patogênicas na presença do sobrenadante in natura e tratado. Os valores de absorbância foram analisados estatisticamente pelos testes de ANOVA e Tukey e os resultados mostraram que os sobrenadantes in natura de L. acidophilus ATCC 4356 L. casei ATCC 7469 e L. plantarum ATCC 8014 foram capazes de inibir 5 das 6 cepas dos patógenos intestinais estudadas em níveis de inibição variando de 23% a 53%, sendo que a cepa S. dysenteriae ATCC 13313 não teve seu crescimento inibido pelas cepas de Lactobacillus avaliadas. Demonstrou-se também que apenas o sobrenadante in natura de L. fermentumATCC 9338 apresentou atividade inibitória sobre esta cepa, cujo percentual de inibição variou entre 20% e 35% e entre 36% e 65% para as demais cepas patogênicas. A avaliação dos resultados relativos ao crescimento das cepas patogênicas na presença dos sobrenadantes in natura e tratados revelou que o efeito de inibição observado foi devido a presença de ácidos orgânicos que provocou o abaixamento do pH. Demonstrou-se ainda a ausência de substâncias peptídicas e termolábeis ativas contra as cepas patogênicas avaliadas, bem como peróxido de hidrogênio nos respectivos sobrenadantes.Infectious diseases caused by gram-negative pathogens are important sources of losses in livestock, especially bovine, ovine and poultry. In many cases, subclinical administration of broad-spectrum antibiotics is chosen as an approach for the prevention of these infections, consequently decreasing these losses. However, this practice presents an important risk to human health, as well as it contributes to the selection of bacterial strains which are resistant to antibiotics usually employed in clinical practice. Therefore, special attention has been given to finding alternative procedures to decrease those losses while eliminating that risk. One of these alternatives consists of using microorganism species which present probiotic properties such as synthesis of inhibitory compounds that act on intestinal pathogen species. This alternative virtually eliminates the risk of developing resistance to broad-spectrum antibiotics, as well as avoids the presence of antibiotic residues in animal products. The term \"probiotic\" is currently used to define microorganism species which promote several benefits to the host, once they are administered frequently and in adequate amounts. In the last few years, several works have been carried out using four Lactobacillus strains (L.acidophilus ATCC 4356, L.casei ATCC 7469, L. fermentum ATCC 9338 and L. plantarum ATCC 8014), and the results have been satisfactory regarding to their probiotic characteristics. Therefore, the aim of this study was to evaluate the ability of these strains to produce inhibitory compounds which are active on gram-negative intestinal pathogen species, specifically Escherichia coli 0112, Escherichia coli 0124, Escherichia coli 0127, Shigella sonnei ATCC 25931, Shigella dysenteriae ATCC 13313 and Salmonella enteritidis ATCC 13076. So, antimicrobial activity of the cell-free supernatant of each strain was evaluated. Additionally, presumptive characterization of these compounds was undertaken by submitting the supernatants to different treatments (catalase, proteolytic enzymes, thermic treatments, pH neutralizing). The strategy consisted of evaluating the growth, estimated by turbidimetry, of the mentioned pathogenic strains in the presence of the original supernatants, as well as in the presence of treated supernatants. Aborbance values were statistically analyzed by means of ANOVA and Tukey\'s test. The results showed that the original supernatants of L. acidophilus ATCC 4356 L. casei ATCC 7469 and L. plantarum ATCC 8014 were capable of inhibiting five of six strains of enteric pathogens at levels varying from 23% to 53%. S. dysenteriae ATCC 13313 was not inhibited by the Lactobacillus strains evaluated. It was also demonstrated that only the original supernatant of L. fermentum ATCC 9338 showed inhibitory activity upon this strain varing from 15% to 32%, and between 36% and 65% regarding to the other strains. Growth evaluation of the pathogenic strains in the presence of the treated and original supernatants revealed that the inhibition effect observed occurred due to the presence of organic acids, which lowered the pH of the supernatants. It was also demonstrated the absence of hydrogen peroxide, peptidic and thermolabile compounds in the supernatants.
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Santos, Hadassa Cristhina de Azevedo Soares dos. "Caracterização molecular e fenotípica da disseminação de diferentes sorotipos de Escherichia coli enteroinvasora em células epiteliais intestinais da linhagem Caco-2." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-16042013-101737/.
Abstract:
Escherichia coli enteroinvasora (EIEC) e Shigella spp. causam disenteria bacilar, caracterizada pela destruição das células epiteliais da mucosa do cólon do hospedeiro. Ambos os microrganismos apresentam características bioquímicas, genéticas e patogênicas semelhantes, porém a doença causada por EIEC se apresenta numa forma mais branda e auto limitante. Dois genes plasmidiais, icsA e icsB estão envolvidos na disseminação intra e intercelular da bactéria, fator importante na produção e resolução da doença. Trabalhos anteriores mostraram que S. flexneri M90T possui uma capacidade maior de disseminação do que o sorotipo de EIEC O124:H-. Devido a esses resultados surgiu a seguinte pergunta: Será que essas diferenças moleculares e fenotípicas estariam restritas ao sorotipo O124:H- ou é comum ao patotipo EIEC? Assim, neste trabalho avaliamos as características fenotípicas e moleculares de onze diferentes sorotipos de EIEC e as comparamos com as amostras de S. flexneri. Pelo ensaio de placas de lise em células Caco-2 mostramos que a capacidade de disseminação de todos os sorotipos de EIEC é menor quando comparada à Shigella M90T. Ao avaliar as sequências gênicas vimos polimorfismos dos genes icsA e icsB dentro do grupo EIEC, assim como em relação aos sorotipos S. flexneri 2a e S. flexneri 5a. A menor disseminação, apresentado pelo patotipo de E. coli, pode estar associada com o processo de ligação e/ou recrutamento de N-WASP, como também na interação com outras proteínas do hospedeiro.Enteroinvasive Escherichia coli (EIEC) and Shigella spp cause bacillary dysentery in humans by invading and multiplying within epithelial cells of the colonic mucosa. Although EIEC and Shigella spp share many genetic and biochemical similarities, the illness caused by EIEC is less severe. The effector proteins IcsA and IcsB are important in the physiopathology of the disease triggered by EIEC and Shigella spp. IcsA is required for intracellular actin-based motility, and the role of IcsB is to camouflage IcsA from the autophagic host defense system. Previous studies showed that EIEC O124:H- showed a significantly less efficient cell-to-cell Caco-2 dissemination when compared with S. flexneri. Due to these results the following question arose: Are molecular and phenotypic differences restricted to serotype O124:H- or is it common to EIEC pathotype? Thus, this study evaluated the phenotypic and molecular characteristics of eleven different serotypes of EIEC and compares them to samples of S. flexneri. All EIEC serotypes presented lower cell-to-cell Caco-2 dissemination compared to Shigella M90T, and the differences between this two species expanded to the icsA and icsB gene sequences, in which it was possible to observe a polymorphism of the genes. The smallest spread presented by EIEC E. coli pathotype could be associated with the connection process and/or recruitment of N-WASP, as well as to other important host proteins.
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Izabel, Hugo de Alencar. "Estudo da proteína OppA em amostras diarreiogênicas de Escherichia coli, Shigella e Salmonella." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-28012008-134840/.
Abstract:
O sistema de captação de oligopeptideos (Opp), responsável pela captação de peptídeos com 3 ou mais resíduos de aminoácidos, representa um mecanismo importante de obtenção de nutrientes em bactérias. O operon Opp é constituído por 5 genes, sendo OppD e F responsáveis pela codificação dos componentes geradores, OppB e C codificantes para as proteínas que delimitam o poro da membrana e OppA que codifica o componente ligante. Neste trabalho identificamos uma alta identidade entre as proteínas OppA expressas por diferentes cepas de E. coli, 4 espécies do gênero Shigella ( 99 %) e diferentes sorovares de Salmonella enterica (85%) mas registramos a ocorrência de vários sítios polimórficos inter-específicos. A presença do gene OppA foi confirmada em 58 cepas diarreiogênicas de E. coli, Shigella e Salmonella. A partir da proteína OppA recombinante foi obtido soro policlonal específico que revelou a presença da proteína em todas as linhagens estudadas. Desta forma, concluímos que a proteína OppA está presente e conversada em espécies e linhagens dos três gêneros de Enterobacteriaceae estudados.The oligopeptide uptake system (Opp), involved with the uptake of peptides formed by 3 or more amino acid residues, represent important nutrient uptake mechanism. The Opp operon is usually represented by 5 structural genes, including OppD and OppF encoding proteins involved generation of energy , OppB and OppC, encoding membrane proteins delimiting a pore and OppA encoding the protein responsible both for specificity and affinity of the transport system toward different peptide substrates. In this study, we demonstrated that the OppA proteins expressed by different E. coli strains,4 Shigella species (99%) and different serovars of Salmonella enterica (85%) were quite conserved but the occurrence of inter-species polymorphism was demonstrated. The OppA gene was detected in 58 diarrheogenic E. coli, Shigella and Salmonella strains. Using a recombinant OppA protein produced in E. coli, specific polyclonal sera were generated and successfully applied in the immunological detection of the proteins expressed by the tested strains. Thus, we conclude that the OppA protein is present and conserved among species and strains of the three test Enterobacteriaceae genera.
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Moreno, Ana Carolina Ramos. "Diferença de patogenicidade entre Escherichia coli enteroinvasora e Shigella flexneri em modelo experimental de infecção intestinal." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-25112016-142513/.
Abstract:
Neste trabalho, esclarecemos tópicos da patogenicidade de EIEC que sustentam a sua menor virulência quando comparada à S. flexneri, e mostramos a importância das células dendríticas (CD) nesse processo. Estudou-se o comportamento de EIEC e S. flexneri quando em contato com células Caco-2, avaliando-se uma cinética de expressão dos genes envolvidos na invasão e disseminação bacteriana. Em geral, todos os genes foram menos expressos em EIEC, fato corroborado pelo fenótipo de disseminação bacteriana, onde EIEC foi menos eficiente do que Shigella. Também foi avaliada a modulação da resposta inflamatória de células dendríticas intestinais murinas pela produção de citocinas, expressão de moléculas co-estimulatórias e apresentação de antígenos, após desafio das células com as bactérias. Os resultados sugerem que EIEC induz a uma resposta protetora ao hospedeiro, enquanto que Shigella estaria \"driblando\" o sistema imune, além de provavelmente super-estimular o sistema imune adaptativo, fato que poderia levar a um agravamento da doença. As ações integradas das células Caco-2, células dendríticas e estímulos bacterianos foram estudadas em co-cultura celular. Observou-se que EIEC e suas proteínas secretadas induzem a migração das CDs ao compartimento apical da co-cultura; nada foi observado quando o desafio se deu com Shigella. Também foram avaliadas as concentrações de citocinas inflamatórias no microambiente infeccioso formado. A citocina TNF-α, bem como CCL20 e MCP-1 foram mais proeminentes após estímulo com EIEC, fato que poderia explicar parcialmente a migração das CDs ao lado apical da co-cultura após estímulo com EIEC e suas proteínas secretadas. Nossas evidências experimentais indicam que a doença desencadeada por EIEC é mais restrita a um determinado local da infecção, ou seja, não é capaz de se disseminar a ponto de estender a lesão tecidual de forma mais drástica, como Shigella. Esse fenômeno pode estar associado à menor expressão de seus dos fatores de virulência e à resposta imune inata induzida no sítio de infecção, o que levaria, fatalmente, à resolução da doença.In this study, we clarify topics of pathogenicity from EIEC that support its lower level of virulence when it is compared to S. flexneri, and we have shown the importance of dendritic cells (DC) in this process. We studied the conduct of EIEC and S. flexneri when they were in contact with Caco-2 cells and we analyzed the kinetics of the genes expression that was involved in the spread and invasion of the bacteria. In general, all genes were expressed less in EIEC, as demonstrated by the phenotype of the bacterial spread, where EIEC was less efficient than Shigella. We also analyzed the modulation of the inflammatory response by the murine intestinal dendritic cells by the production of cytokine, expression of co-stimulators molecules and antigens presentation, after the interaction of the cells with the bacteria. The results showed that EIEC induces a response that protects the host while Shigella manipulate the host intestinal innate and adaptive immune system and it probably over-stimulates the adaptive immune system which could let the disease worse. The integrated actions of Caco-2 cells, dendritic cells and bacterial stimulus, were studied in a co-culture cell. We observed that EIEC and its secreted proteins induce the migration of the DCs to the apical compartment of the co-culture; nothing was observed related to Shigella. We also evaluated the concentrations of the inflammatory cytokines at the infective micro environment that was formed. The cytokine TNF-α, as CCL20 and MCP-1 were more prominent after been stimulated with EIEC, a fact that could partially explain the migration of DCs to the apical side of the co-culture after the stimulus with EIEC and its secreted proteins. Our experimental evidence shows that the disease triggered by the EIEC is more restricted at a definite infection place, which means that it is not capable of disseminating beyond a certain point to extend the tissue\'s injury and let it worsen, as Shigella do. This phenomenon can be associated with the lower level of expression of its virulence factors and to the immune response induced in the infection site, what could finally lead to the eradication of the disease.
7
Li, Yong. "Simultaneous detection of Escherichia coli O157:H7, Salmonella and Shigella by polymerase chain reaction-based methods /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcitt?p3144436.
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Silva, Gracie Luiza da. "Estudo da ação inibitória da quitosana sobre os enteropatógenos: Salmonella enterica, Shigella sonnei e Escherichia coli EPEC." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-10052006-095954/.
Abstract:
Este estudo teve por objetivo avaliar a ação inibitória de duas soluções de quitosana através da determinação da concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM) de duas soluções de quitosana de diferentes procedências. A primeira solução de quitosana derivada de camarão, do tipo comercial Fluka, de PM 600.000 g/mol, G.A. 76% e a segunda solução de quitosana derivada de lula, de PM: '10 POT.7' g/mol e G.A.: 83%. As duas soluções foram ajustadas ao pH 5,0 e na concentração de 0,5% em solução acética a 1%. A melhor atividade antimicrobiana da quitosana ocorre em pH igual ou menor que cinco e ela sofre precipitação em pH superiores a 6,5. Estas duas características foram determinantes na escolha do pH utilizado no teste da CIM. Para confirmar que a inibição do crescimento dos enteropatógenos ocorreu pela ação da quitosana e não pelo pH ácido dos meios, vários testes foram realizados. A avaliação do crescimento dos enteropatógenos em ágar MacConkey, pH 5,0 (ótimo para quitosana) e 7,4(ótimo para o cultivo das bactérias utilizadas), o inóculo de cada bactéria foi preparado segundo o tubo 0,5 de Mc Farland (controle positivo), e a avaliação foi repetida utilizando o inóculo diluído 1:1000 para contagem do número de colônias, e não apresentaram diferenças significativas. Para confirmar estes dados foram realizados os controles negativos das duas soluções de quitosana e do meio de cultura MacConkey em pH 5,0 e 7,4, incubados a 37°C e lidos por 72 horas, sem qualquer alteração. A avaliação da reação de precipitação foi feita em caldo Müeller Hinton em pH 4,0; 5,0; 6,0; 7,0 e 8,0 para as duas soluções de quitosana (v/v), incubados a 37°C e lidos por 72 horas. A avaliação da CIM das duas soluções de quitosana para os enteropatógenos foi realizada por diluição seriada e os inóculos comparados ao tubo 0,5 de Mc Farland, sendo 10 'mü'L da suspensão bacteriana acrescida a cada tubo, incubados a 37°C por 24 horas. A leitura da ausência de turvação visível caracterizou a CIM. Todos os tubos que não apresentaram turvação visível foram plaqueados em ágar MacConkey, em pH 7,4 e incubados a 37°C por 24 horas para determinação da CBM, a qual foi determinada pela menor concentração capaz de causar morte total da população dos enteropatógenos. Todas as técnicas foram realizadas em triplicata para confirmação dos resultadosThe aim of this study was to evaluate the inhibitory action of chitosan solutions derived from shrimp (Fluka commercial type, MW 600.000 g/mol, acetylation degree of 76%) and squid (MW '10 POT.7' g/mol, acetylation degree of 83%) through determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against enteropathogens: Salmonella enterica, Shigella sonnei and Escherichia coli EPEC. Those solutions were set to pH 5,0 and a 0,5% concentration in a 1% acetic acid solution. The best antimicrobial activity of chitosan occurs in pH less than or equal to 5,0 and it shows precipitation in pH greater than 6,5. Those features were decisive to choose the pH used in the MIC test. In order to confirm that the growth inhibition of enteropathogens occurred by the action of chitosan and not for the acid pH of the environments, growth evaluation tests of enteropathogens were accomplished in MacConkey agar, pH 5,0 (excellent for chitosan) and pH 7,4 (excellent for culture of used bacteria). The inoculum of each bacterium was prepared comparing with the 0,5 tube of McFarland (positive control) and the evaluation was repeated using the inoculum diluted in a salt solution 1:1000 to count the number of colonies, which did not show significant differences. The reaction evaluation of precipitation of chitosan was done in Müeller Hinton broth with pH ranging 4,0 - 8,0 for both solutions of chitosan (v/v), which were incubated at 37°C and read for 72 hours. The MIC evaluation for both solutions of chitosan for the enteropathogens was done by serial dilution and the inocula were compared to the 0,5 tube of McFarland, adding 10 'mü'L of bacterial suspension to each tube, which were incubated at 37°C for 24 hours. The MIC was distinguished by the absence of visible turbidity. Each tube that did not show visible turbidity was spread on MacConkey agar plates in pH 7,4, and incubated at 37°C for 24 hours to find the MBC, which was determined by the smallest concentration able to cause total death to the enteropathogen population. In both cases, the solutions of chitosan presented a high antimicrobial activity against the enteropathogens Salmonella enterica and Escherichia coli EPEC. However, the higher antimicrobial activity was observed in the enteropathogen Shigella sonnei
9
Pilonieta, Maria Carolina. "Transcriptional Regulation of Virulence Genes in Enterotoxigenic Escherichia coli and Shigella flexneri by Members of the AraC/XylS Family." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/111.
Abstract:
Pathogenesis of enterotoxigenic Escherichia coli (ETEC) and Shigella flexneri relies predominantly on members of the AraC/XylS family of transcriptional regulators, Rns (or its homolog, CfaD) and MxiE, respectively. Rns/CfaD regulate the expression of pili, which allow the bacteria to attach to the intestinal epithelium. Better understanding of the role Rns plays in virulence was attained by expanding our knowledge of the Rns regulon, revealing that it functions as an activator of cexE, a previously uncharacterized gene. By in vitro DNase I footprinting two Rns-binding sites were identified upstream of cexEp, both of which are required for full activation of cexE. The amino terminus of CexE also contains a secretory signal peptide that is removed during translocation to the periplasm. Though the function of CexE remains unknown, these studies suggest that CexE is a novel ETEC virulence factor since it is regulated by Rns/CfaD. In Shigella flexneri, the expression of a subset of virulence genes (including, ipaH9.8 and ospE2) is dependent upon the activator MxiE and a cytoplasmic chaperone IpgC. To define the molecular mechanism of transcriptional activation by this chaperone-activator pair, an in vitro pull down assay was performed revealing that MxiE specifically interacts with IpgC in a complex. Additionally, IpgC recognizes three polypeptide regions in MxiE: within MxiE(1-46), MxiE(46-110) and MxiE(196-216). Furthermore, it seems that MxiE and IpgC regulate transcription of ipaH9.8 and ospE2 promoters differently. In the bacterium, the formation of the MxiE-IpgC complex is initially prevented because IpgC is sequestered in individual complexes with effector proteins, IpaB and IpaC. Upon contact with an eukaryotic host cell the effector proteins are secreted, thereby freeing IpgC to form a complex with MxiE and activate the expression of virulence genes. This new characterization of the role of Rns and MxiE in virulence gene regulation in ETEC and S. flexneri, respectively will give new insights into the pathogenesis of the regulators.
10
Silva, Renée de Nazaré Oliveira da. "Caracterização molecular dos genes ospC1, ospG e ospF em diferentes sorotipos de Escherichia coli enteroinvasora." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-26042013-093005/.
Abstract:
Escherichia coli enteroinvasora (EIEC) é um dos agentes etiológicos da disenteria bacilar, caracteriza-se pela destruição do epitélio do cólon provocado pela resposta inflamatória induzida após invasão da mucosa por bactérias. Cepas de EIEC são bioquímica, genética e patogênica semelhante a Shigella spp. A patogenicidade de EIEC e Shigella dependem da presença da pInv plasmídeo, que contém os genes necessários para a colonização bacteriana na mucosa intestinal. Recentemente, demonstrou-se que genes plasmidias ospC1, ospG e ospF de S. flexneri estão envolvidos na inibição da resposta inflamatória em células epiteliais intestinais, um fator importante na iniciação da colonização bacteriana e produção de doença. Como a EIEC mostrou doença menos grave, foi analisada as sequências de aminoácido, avaliada a transcrição destes genes plasmídiais e resposta inflamatória modulada por este micro-organismo na célula epitelial intestinal Caco-2. As células Caco-2 foram infectadas em momentos diferentes com 11 sorotipos de EIEC e S. flexneri (M90T). Os dados sobre a capacidade de invasão e sobrevivência de bactérias, expressão de genes de bactérias e da quimiocina IL-8 foram obtidos por CFU, RT-PCR, e ELISA, respectivamente. A significância estatística foi avaliada por ANOVA de dois fatores. Os 11 sorotipos de EIEC estudados apresentaram similaridade de 100% com S.flexneri para OspC1 e OspF,contudo, foram diferentes na homologia do OspG. Quando comparamos as sequências de aminoácido dos 11 sorotipos observamos 100% de similaridade entre eles para OspG, sugerindo o envolvimento destas proteínas na modulação da resposta imune induzida por estes micro-organismos. Os sorotipos de EIEC apresentam diferenças na capacidade de invasão dos enterócitos. Algumas diferenças significativas foram observadas na transcrição dos genes e na produção de IL-8. Os sorotipos de EIEC O29: H-e O167: H-apresentou um baixo transcrição de genes ospC1 e ospF, e um aumento significativo na produção de IL-8 quando comparado com outros sorotipos. Além disso, demonstrou que a maior transcrição destes genes por alguns sorotipos de EIEC parecem estar relacionados com a menor indução de IL-8. Estes dados sugerem que as proteínas OspC1 e OspF desempenham um papel na resposta inflamatória. No entanto, não se observou relação na transcrição ospG para a produção de IL-8. Estes resultados sugerem que as proteinas efetoras OspC1 e OspF estão envolvidas na inibição da resposta inflamatória em células epiteliais do intestino favorecendo a invasão da EIEC.Enteroinvasive E. coli (EIEC) is one of the etiological agents of bacillary dysentery, it is characterized by the destruction of the colonic epithelium caused by the inflammatory response induced upon invasion of the mucosa by bacteria. Strains of EIEC are biochemical, genetic and pathogenic similar to Shigella spp. The pathogenecity of EIEC and Shigella depend on the presence of the plasmid pInv, which contains the genes necessary for bacterial colonization in the intestinal mucosa. Recently, it was demonstrated that the plasmid genes ospC1, ospG and ospF of S. flexneri are involved in inhibition of the inflammatory response in intestinal epithelial cells, an important factor in the initiation of bacterial colonization and production of disease. As EIEC has showed less severe disease, we evaluated the transcription of these plasmid genes and inflammatory response modulated by this microorganism in the intestinal epithelial cell Caco-2. The Caco-2 cells were infected in different times with 11 serotypes of EIEC and S. flexneri M90T strain. The data about sequences of amino acids, invasiveness and survival of bacteria, bacterial genes expression, and chemokine IL-8 were obtained by CFU, RT-PCR, and ELISA, respectively. The statistical significance was evaluated by two-way ANOVA. All EIEC serotypes studied showed 100% similarity with S.flexneri to OspC1 and OSPF, however, were different in the homology of OspG. Compared the amino acid sequences of the 11 serotypes observed 100% similarity between them to OspG, suggesting the involvement of them in modulating of the immune response induced by these microorganisms. There were no differences in the invasion the enterocytes among EIEC serotypes. However, some significant differences were observed in the transcription of those genes and production of IL-8. The EIEC serotypes O29:H- and O167:H- showed a low transcription of genes ospC1 and ospF, and a significant increase in production of IL-8 when compared with other serotypes. Furthermore, it was shown that the high transcription of ospF and ospC1 by some EIEC serotypes are related to low induction of IL-8. These data suggested that the proteins OspC1 and OspF play a role in the inflammatory response. However, we did not observed association between ospG transcription to the production of IL-8. These results lead us to believe that the effector proteins OspF and OspC1 are involved in inhibition of the inflammatory response in intestinal epithelial cells favoring the EIEC invasion.
Books on the topic "Escherichia-Shigella":
1
Matthews, Philippa C. Infections caused by Gram-negative bacteria. Edited by Philippa C. Matthews. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198737773.003.0004.
Abstract:
This chapter consists of short notes, diagrams, and tables to summarize Gram-negative organisms that are significant causes of disease in the tropics and subtropics. This includes Escherichia coli, Shigella, and Salmonella species (including typhoid and paratyphoid), Brucella, melioid, Campylobacter, and meningococci. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment, and prevention.
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Bowdler, Robert W. Determination of "biotin" operon homology among the "Enterobacteriaceae: Escherichia coli salmonella typhimurium" and "Shigella dysenterial" using © rH-RNA-DNA by hybridization. 1985.
Book chapters on the topic "Escherichia-Shigella":
1
Strockbine, Nancy A., Cheryl A. Bopp, Patricia I. Fields, James B. Kaper, and James P. Nataro. "Escherichia , Shigella , and Salmonella." In Manual of Clinical Microbiology, 685–713. Washington, DC, USA: ASM Press, 2015. http://dx.doi.org/10.1128/9781555817381.ch37.
2
Perna, Nicole T. "Genomics of Escherichia and Shigella." In Genomics of Foodborne Bacterial Pathogens, 119–39. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-7686-4_5.
3
Belotserkovsky, Ilia, and Philippe J. Sansonetti. "Shigella and Enteroinvasive Escherichia Coli." In Current Topics in Microbiology and Immunology, 1–26. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/82_2018_104.
4
Baylis, Christopher L., Charles W. Penn, Nathan M. Thielman, Richard L. Guerrant, Claire Jenkins, and Stephen H. Gillespie. "Escherichia coli and Shigella spp." In Principles and Practice of Clinical Bacteriology, 347–65. Chichester, UK: John Wiley & Sons, Ltd, 2006. http://dx.doi.org/10.1002/9780470017968.ch28.
5
Payne, Shelley M., and Alexandra R. Mey. "Pathogenic Escherichia coli, Shigella, and Salmonella." In Iron Transport in Bacteria, 197–218. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555816544.ch14.
6
Dobrindt, Ulrich, and Jörg Hacker. "Pathogenomics of Escherichia coli and Shigella Species." In Pathogenomics, 83–108. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/352760801x.ch5.
7
Parsot, Claude, and Philippe Sansonetti. "Evolution of Shigella and Enteroinvasive Escherichia coli." In Evolutionary Biology of Bacterial and Fungal Pathogens, 421–31. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555815639.ch35.
8
Melton-Celsa, A. R., and A. D. O’Brien. "Shiga Toxins of Shigella dysenteriae and Escherichia coli." In Bacterial Protein Toxins, 385–406. Berlin, Heidelberg: Springer Berlin Heidelberg, 2000. http://dx.doi.org/10.1007/978-3-662-05971-5_17.
9
Jay, James M. "Foodborne Gastroenteritis Caused by Salmonella, Shigella, and Escherichia." In Modern Food Microbiology, 553–82. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-6480-1_22.
10
Venkatesan, Malabi M., Jerry M. Buysse, and Dennis J. Kopecko. "DNA Sequence Homology Among ipa Genes of Shigella spp. and Enteroinvasive Escherichia coli." In Progress in Vaccinology, 205–15. New York, NY: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4612-3508-8_20.
Conference papers on the topic "Escherichia-Shigella":
1
Al-Asmar, Jawaher, Sara Rashwan, and Layla Kamareddine. "The use of Drosophila Melanogaster as a Model Organism to study the effect of Bacterial Infection on Host Survival and Metabolism." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0186.
Abstract:
Enterobacteriaceae, a large family of facultative anaerobic bacteria, encloses a broad spectrum of bacterial species including Escherichia coli, Salmonella enterica, and Shigella sonnei, that produce enterotoxins and cause gastrointestinal tract diseases. While much is known about the regulation and function of enterotoxins within the intestine of the host; the lack of cheap, practical, and genetically tractable model organisms has restricted the investigation of others facets of this host-pathogen interaction. Our group, among others, has employed Drosophila melanogaster, as a model organism to shed more light on some aspects of host-pathogen interplays. In this project, we addressed the effect of Escherichia coli, Salmonella enterica, and Shigella sonnei infection on altering the metabolic homeostasis of the host. Drosophila melanogaster flies were orally infected with Escherichia coli, Salmonella enterica, or Shigella sonnei, a method that mimics the natural route used by enteric pathogens to gain access to the gastrointestinal tract in humans. The results of our study revealed that both Escherichia coli and Shigella sonnei pathogens were capable of colonizing the host gut, resulting in a reduction in the life span of the infected host. Escherichia coli and Shigella sonnei infected flies also exhibited altered metabolic profiles including lipid droplets deprivation from their fat body (normal lipid storage organ in flies), irregular accumulation of lipid droplets in their gut, and significant elevation of systemic glucose and triglyceride levels. These metabolic alterations could be mechanistically attributed to the differential down-regulation in the expression of metabolic peptide hormones (Allatostatin A, Diuretic hormone 31, and Tachykinin) detected in the gut of Escherichia coli and Shigella sonnei infected flies. Salmonella enterica; however, was unable to colonize the gut of the host; and therefore, Salmonella enterica infected flies exhibited a relatively normal metabolic status as that of non infected flies. Gaining a proper mechanistic understanding of infection-induced metabolic alterations helps in modulating the pathogenesis of gastrointestinal tract diseases in a host and opens up for promising therapeutic approaches for infection induced metabolic disorders
2
Somaratne, Yamuna, Manori Perera, and Renuka Karunagoda. "Evaluation of Antibacterial Activity of Rhinacanthus Species in Sri Lanka." In SLIIT International Conference on Advancements in Sciences and Humanities 2023. Faculty of Humanities and Sciences, SLIIT, 2023. http://dx.doi.org/10.54389/ksch3510.
Abstract:
Rhinacanthus nasutus (L.) Kurz is a valuable medicinal plant belonging to the family Acanthaceae that has many applications in the Ayurvedic system of medicine in Sri Lanka. Rhinacanthus polonnaruwensis Cramer is a more recently discovered species endemic to Sri Lanka, but its medicinal properties have not been recorded so far. The objective of the present study was to screen the antibacterial activity of leaf extracts of R. nasutus and R. polonnaruwensis against clinically isolated Gram-negative and Gram-positive bacteria. The study was carried out on six bacterial species, Escherichia coli, Staphylococcus aureus, S. saprophyticus, Pseudomonas aeruginosa, Salmonella typhi and Shigella flexi. Polar extracts of R. nasutus and R. polonnaruwensis were obtained by grinding the leaves with sterilized water and boiling the leaves in distilled water to obtain a decoction. A decoction of the concentration of 0.2 ml/ml of R. nasutus inhibited growth of all standard Gram-positive bacteria; Staphylococcus aureus and MRSA, whereas 0.2 ml/ml of decoction of R. polonnaruwensis inhibited growth of Staphylococcus aureus. Clinically isolated Staphylococcus saprophyticus was inhibited by both decoctions of Rhinacanthus species. None of the tested concentrations of the two Rhinacanthus species inhibited the growth of any Gram-negative bacteria; Pseudomonas aeruginosa, Escherichia coli, and Shigella flexi. In this study, we demonstrated that the leaf extracts of both R. nasutus and R. polonnaruwensis were effective at inhibiting Gram-positive bacteria. However, the decoction of R. nasutus was found to be more effective against the tested Gram positive bacteria than R. polonnaruwensis.
3
Obistioiu, Diana, Ileana Cocan, Calin Hulea, Monica Negrea, and Ersilia Alexa. "IN VITRO EVALUATION OF BOSWELLIA SPP. ANTI-BIOFILM ACTIVITY." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022v/6.2/s25.26.
Abstract:
Recent years have seen an increase in microbial biofilm resistance, which has led to great challenges for the medical community in terms of treating diseases and the food industry in terms of contamination and the loss of shelf life. The purpose of this work is to test the antimicrobial efficacy against the biofilm formed by the following reference strains: Streptococcus pyogenes (ATCC 19615), Staphylococcus aureus (ATCC 25923), Shigella flexneri (ATCC 12022), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli ( ATCC 25922), Salmonella typhimurium (ATCC 14028), Haemophilus influenzae type B (ATCC 10211), Listeria monocytogenes (ATCC 19114), Bacillus cereus (ATCC 10876) Clostridium perfringens (ATCC 13124), Candida parapsilopsis (ATCC 22019) and Candida albicans ( ATCC 10231) as well as the MBIC evaluation of the essential oil of Boswellia spp. The evaluation was performed by evaluating the loss of microbial mass by measuring the OD by spectrophotometry in accordance with ISO 20776- 1:2019. The statistically evaluated results suggest a very good efficacy against Grampositive bacteria and fungi and a more limited activity against Gram-negative bacteria.
4
Obistioiu, Diana, Anca Hulea, Ilinca Imbrea, Iuliana Popescu, and Florin Imbrea. "ELETTARIA CARDAMOMUM: CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITY. AN IN VITRO STUDY." In 23rd SGEM International Multidisciplinary Scientific GeoConference 2023. STEF92 Technology, 2023. http://dx.doi.org/10.5593/sgem2023v/6.2/s25.19.
Abstract:
Recent years have seen an increase in microbial resistance, which has led to great challenges for the medical community in terms of treating diseases and the food industry in terms of contamination and the loss of shelf life. This research aimed to evaluate the chemical composition and antimicrobial activity of the essential oil of Elettaria cardamomum against the following reference strains: Streptococcus pyogenes (ATCC 19615), Staphylococcus aureus (ATCC 25923), Shigella flexneri (ATCC 12022), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli ( ATCC 25922), Salmonella typhimurium (ATCC 14028), Haemophilus influenzae type B (ATCC 10211), Listeria monocytogenes (ATCC 19114), Bacillus cereus (ATCC 10876) Clostridium perfringens (ATCC 13124), Candida parapsilopsis (ATCC 22019) and Candida albicans ( ATCC 10231). The chemical analysis revealed 24 GC-MS- identified compounds using a Shimadzu QP 2010 Plus apparatus (Columbia, SC, USA) equipped with an AT WAX 30 m 0.32 mm 1 ?m capillary column. The antimicrobial activity and MIC evaluation using the microdilution method suggested a higher efficacy against Gram-positive bacteria and fungi than Gram-negative bacteria.
5
Floares, Doris, Diana Obistioiu, Anca Hulea, Ersilia Alexa, and Isidora Radulov. "THUJA OCCIDENTALIS AND PLATYCLADUS ORIENTALIS ANTIMICROBIAL ACTIVITY." In 23rd SGEM International Multidisciplinary Scientific GeoConference 2023. STEF92 Technology, 2023. http://dx.doi.org/10.5593/sgem2023v/6.2/s25.57.
Abstract:
The rise of bacterial resistance to currently employed antibiotics is causing growing concerns for public health. The emergence of highly resistant bacterial strains results in the ineffectiveness of antibiotic treatments against many bacterial infections. As a result, there is an ongoing quest for new antimicrobial agents. This pursuit can take two main directions: one involves the design and synthesis of novel agents, while the other involves exploring natural sources to uncover previously undiscovered antimicrobial compounds. Herbal medications, particularly, have garnered renewed interest due to the perception that they tend to cause fewer adverse reactions when compared to synthetic pharmaceuticals. Moreover, the lower costs of producing plant-based preparations make searching for natural therapeutics appealing. This study aims to assess the antimicrobial properties of Thuja occidentalis (TO) and Platycladus orientalis (PO) against Gram-positive and Gram-negative bacteria using specified reference strains: Streptococcus pyogenes (ATCC 19615), Staphylococcus aureus (ATCC 25923), Listeria monocytogenes (ATCC 19114), Bacillus cereus (ATCC 10876), Clostridium perfringens (ATCC 13124), Shigella flexneri (ATCC 12022), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Salmonella typhimurium (ATCC 14028) and Haemophilus influenzae type B (ATCC 10211) Additionally, we determined the minimum inhibitory concentration (MIC). Following ISO 20776-1:2019 guidelines, we assessed the antimicrobial activity by measuring the reduction in microbial mass through spectrophotometry to determine changes in optical density (OD). Our findings indicate that the TO and PO extracts inhibit Gram-positive bacteria, particularly at the initial concentration tested.
6
Покровская, Е. В., Е. А. Шестакова, М. С. Синеокая, Н. С. Клименко, and М. В. Шестакова. "ИЗМЕНЕНИЕ МЕТАБОЛИЧЕСКИХ ПОКАЗАТЕЛЕЙ И СОСТАВА КИШЕЧНОЙ МИКРОБИОТЫ У ПАЦИЕНТОВ С МОРБИДНЫМ ОЖИРЕНИЕМ И САХАРНЫМ ДИАБЕТОМ 2 ТИПА ПОСЛЕ МИНИГАСТРОШУНТИРОВАНИЯ." In Сборник тезисов III Конференции по лечению и диагностике сахарного диабета «Фундаментальная и клиническая диабетология в 21 веке: от теории к практике». ФГБУ «НМИЦ эндокринологии» Минздрава России, 2023. http://dx.doi.org/10.14341/diaconfiii25-26.05.23-79.
Abstract:
Бариатрическая хирургия является одним из самых эффективных способов снижения веса, а также
способствует улучшению показателей углеводного обмена у пациентов с ожирением и сахарным диабетом
2 типа (СД 2) типа вплоть до развития ремиссии СД 2. Достижение ремиссии СД 2 после бариатрической
операции варьирует от 30 до 98% и зависит от различных факторов. Ряд исследований показал наличие
изменений микробиоты кишечника (КМ) после бариатрических операций. Представляется интересным
связь между достижением ремиссии СД 2 и изменением состава КМ.
ЦЕЛЬ: оценить динамику изменения состава кишечной микробиоты у пациентов после бариатриче-
ского вмешательства.
МАТЕРИАЛЫ И МЕТОДЫ: в исследование были включены пациенты с морбидным ожирением (индекс
массы тела (ИМТ) ≥ 40 кг/м2) и СД 2, которым была выполнена бариатрическая операция в объеме лапаро-
скопического минигастрошунтирования. Проводилась оценка динамики массы тела, метаболических по-
казателей, гормонов ЖКТ, а также состава микробиоты и метаболома стула исходно и через 6 и 12 месяцев
после оперативного вмешательства.
РЕЗУЛЬТАТЫ: в исследование включено 28 пациентов. Через 12 месяцев после оперативного лечения
наблюдается снижение веса относительно исходного на – 42 кг [-57.4; -35], достижение целевых показа-
телей гликированного гемоглобина (HbA1с) c 6.8% [6.3; 7.9] до 5.7% [5.3; 5.9]. Половина пациентов (n=14)
достигли полной ремиссии СД после операции с отменой сахароснижающей терапии. Также отмечалось
значимое улучшение липидного профиля и уровня мочевой кислоты, снижение инсулинорезистентности
(ИР). При оценке гормонов ЖКТ наблюдалось значительное увеличение базального уровня адипонектина
после операции; в отношении базальной секреции инкретиновых гормонов (ГПП-1, глюкагон) значимых
различий получено не было. Также наблюдалось снижение маркеров хронического системного воспа-
ления: уровня эндотоксина и С-реактивного белка (СРБ) в крови у пациентов. Части пациентов (n=17)
проведены полногеномное секвенирование и метаболомный анализ КМ. В результате зафиксированы
изменения в уровне ряда метаболитов в контрольной точке 6 месяцев после операции, однако, к концу
наблюдения состав метаболитов был схож с их дооперационным уровнем. При этом зафиксированное
изменение представленности некоторых таксонов бактерий (Fuzobacterium, Escherichia/Shigella, Gemella)
сохранялись к концу наблюдения.
ВЫВОДЫ: минигастрошунтирование сопровождается значимым улучшением метаболического профиля
пациентов с ожирением и СД 2, а также динамикой состава КМ. Требуются дальнейшие исследования для
оценки ассоциации между достижением ремиссии СД 2 и профилем КМ.
ФИНАНСИРОВАНИЕ: работа выполнена в рамках государственного задания НИОКТР 123021300168-7
«Воздействие на органы чувств (обоняние и вкус) и микробиоценоз ЖКТ с целью регуляции аппетита, веса
и гликемии при сахарном диабете 2 типа».
Reports on the topic "Escherichia-Shigella":
1
McAvin, James C., and Carl J. Mason. Pre-Clinical Testing of Real-Time PCR Assays for Diarrheal Disease Agents of Genera Escherichia and Shigella. Fort Belvoir, VA: Defense Technical Information Center, May 2014. http://dx.doi.org/10.21236/ada600976.
2
Irudayaraj, Joseph, Ze'ev Schmilovitch, Amos Mizrach, Giora Kritzman, and Chitrita DebRoy. Rapid detection of food borne pathogens and non-pathogens in fresh produce using FT-IRS and raman spectroscopy. United States Department of Agriculture, October 2004. http://dx.doi.org/10.32747/2004.7587221.bard.
Abstract:
Rapid detection of pathogens and hazardous elements in fresh fruits and vegetables after harvest requires the use of advanced sensor technology at each step in the farm-to-consumer or farm-to-processing sequence. Fourier-transform infrared (FTIR) spectroscopy and the complementary Raman spectroscopy, an advanced optical technique based on light scattering will be investigated for rapid and on-site assessment of produce safety. Paving the way toward the development of this innovative methodology, specific original objectives were to (1) identify and distinguish different serotypes of Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Bacillus cereus by FTIR and Raman spectroscopy, (2) develop spectroscopic fingerprint patterns and detection methodology for fungi such as Aspergillus, Rhizopus, Fusarium, and Penicillium (3) to validate a universal spectroscopic procedure to detect foodborne pathogens and non-pathogens in food systems. The original objectives proposed were very ambitious hence modifications were necessary to fit with the funding. Elaborate experiments were conducted for sensitivity, additionally, testing a wide range of pathogens (more than selected list proposed) was also necessary to demonstrate the robustness of the instruments, most crucially, algorithms for differentiating a specific organism of interest in mixed cultures was conceptualized and validated, and finally neural network and chemometric models were tested on a variety of applications. Food systems tested were apple juice and buffer systems. Pathogens tested include Enterococcus faecium, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Yersinia enterocolitis, Shigella boydii, Staphylococus aureus, Serratiamarcescens, Pseudomonas vulgaris, Vibrio cholerae, Hafniaalvei, Enterobacter cloacae, Enterobacter aerogenes, E. coli (O103, O55, O121, O30 and O26), Aspergillus niger (NRRL 326) and Fusarium verticilliodes (NRRL 13586), Saccharomyces cerevisiae (ATCC 24859), Lactobacillus casei (ATCC 11443), Erwinia carotovora pv. carotovora and Clavibacter michiganense. Sensitivity of the FTIR detection was 103CFU/ml and a clear differentiation was obtained between the different organisms both at the species as well as at the strain level for the tested pathogens. A very crucial step in the direction of analyzing mixed cultures was taken. The vector based algorithm was able to identify a target pathogen of interest in a mixture of up to three organisms. Efforts will be made to extend this to 10-12 key pathogens. The experience gained was very helpful in laying the foundations for extracting the true fingerprint of a specific pathogen irrespective of the background substrate. This is very crucial especially when experimenting with solid samples as well as complex food matrices. Spectroscopic techniques, especially FTIR and Raman methods are being pursued by agencies such as DARPA and Department of Defense to combat homeland security. Through the BARD US-3296-02 feasibility grant, the foundations for detection, sample handling, and the needed algorithms and models were developed. Successive efforts will be made in transferring the methodology to fruit surfaces and to other complex food matrices which can be accomplished with creative sampling methods and experimentation. Even a marginal success in this direction will result in a very significant breakthrough because FTIR and Raman methods, in spite of their limitations are still one of most rapid and nondestructive methods available. Continued interest and efforts in improving the components as well as the refinement of the procedures is bound to result in a significant breakthrough in sensor technology for food safety and biosecurity.
3
Cairo, Jessica, Iulia Gherman, and Paul Cook. The effects of consumer freezing of food on its use-by date. Food Standards Agency, July 2021. http://dx.doi.org/10.46756/sci.fsa.ret874.
Abstract:
The current Food Standards Agency consumer guidance states that consumers can freeze pre-packed food right up to the “use-by” date and, once food has been defrosted, it should be consumed within 24 hours. This strategic review has collated relevant data to determine whether there is an increased risk in relation to freezing ready-to-eat and non-ready-to-eat foods on the use-by date compared to the day before the use-by date. The review has focused on how the shelf-life of a food is determined and the effects of freezing, thawing and refrigeration on foodborne pathogens, including Bacillus spp., Campylobacter spp., Clostridium botulinum, Clostridium perfringens, Listeria monocytogenes, Salmonella, pathogenic Escherichia coli and Shigella spp. In the UK, food business operators are responsible for setting the safe shelf-life of a food which, in practice, should take into consideration the consumer habits, as well as the factors affecting shelf-life, such as food product characteristics, food processing techniques, transport, retail and domestic food storage temperatures, and type of packaging. Some countries, such as Ireland, New Zealand and Canada specifically recommend including safety margins within shelf lives. This is used to maintain brand integrity because it ensures that the food is consumed in its optimum condition. The FSA has collaborated with other organisations in the production of several guidance documents; however, there is no explicit requirement for the consideration of a margin of safety when setting shelf-life. There is also no legal requirement in the UK to consider a safety margin when setting shelf-life. According to regulations, pathogens should not be present in sufficient levels to cause foodborne illness on the use-by date, as food should still be safe to eat on that day. Given that these requirements are met, the risk assessed in this report arises from the processes of freezing, thawing and subsequent refrigerated storage for a further 24 hours, and the potential for these to increase pathogen levels. In this review, it was found that there is a risk of additional growth of certain pathogens during the refrigerated storage period although the impact of freezing and thawing on the extent of this growth was not readily evident. This risk would relate specifically to ready-to-eat foods as cooking of non-ready-to-eat foods after defrosting would eliminate pathogens. This report explores the potential issues related to consumer freezing on the use-by date and identifies additional information or research required to understand the risks involved. Overall, there is little evidence to suggest a significant change in risk between consumers freezing ready-to-eat food on the use-by date compared to freezing the food on the day before the use-by date. Specific areas that merit further research include the risks due to low temperature survival and growth of L. monocytogenes. There is also a lack of research on the effects of freezing, defrosting and refrigeration on the growth and toxin production of non-proteolytic C. botulinum, and the growth of Salmonella during domestic freezing and thawing. Finally, more information on how food business operators set shelf-life would enable a better understanding of the process and the extent of the safety margin when determining shelf-life of ready-to-eat and non-ready-to-eat foods.