Auswahl der wissenschaftlichen Literatur zum Thema „Rezistence bakterií“

Višestruko rezistentne bakterije, uzročnici hospitalnih infekcija, kao što su Acinetobacter baumannii i Klebsiella pneumoniae, predstavljaju globalni problem 21. stoljeća. Osobito zabrinjava sve učestalija pojava otpornosti ovih mikroorganizama na komercijalno dostupne dezinficijense. Cilj našeg istraživanja bio je utvrditi učinkovitost dezinfekcije proizvoda „Sanosil super25“, u odnosu na vodikov peroksid i to na višestruko rezistentne izolate A. baumannii i K. pneumoniae. Ispitane su vrijednosti MTC (maksimalno tolerirajuća koncentracija); MIC (minimalna inhibirajuća koncentracija) i MBC (minimalna baktericidna koncentracija). MTC Sanosila (<1.25 ppm) bila je dvostruko manja u odnosu na vodikov peroksid. MIC-e Sanosila (1.25 ili <1.25 ppm) su bile 4 puta manje u odnosu na vodikov peroksid. MBC koja rezultira izostankom vijabilnih bakterija za Sanosil je bila <1.25 ppm već nakon 5 min kontakta, što je barem 8 puta niža koncentracija u odnosu na vodikov peroksid. Rezultati su pokazali da je Sanosil super25 bio učinkovitiji u sve tri kategorije, u odnosu na vodikov peroksid.

Izvleček Prevalenca Helicobacter pylori okužbe v razvitem svetu je nižja od 20 %. Helicobacter pylori infekcija pri otrocih v večini primerov povzroči asimptomatski kronični gastritis. Kronične bolečine v trebuhu, če ob endoskopiji zgornjih prebavil ne odkrijemo erozij ali ulkusov, pri otrocih niso povezane z bakterijsko okužbo. Glede na to diagnostika Helicobacter pylori okužbe z neinvazivnimi testi v otroštvu ni priporočljiva. Zdravljenje naj bo usmerjeno glede na antibiotično rezistenco seva bakterije, ki smo ga izolirali iz biopta želodčne sluznice ob endoskopiji zgornjih prebavil. V članku so povzeta priporočila, ki smo jih oblikovali letos v Odboru za Helicobacter pylori okužbo v okviru Severnoameriškega in Evropskega pediatričnega združenja za gastroenterologijo, hepatologijo in prehrano (NASPGHAN, ESPGHAN) na podlagi sistematičnega pregleda objavljenih raziskav s tega področja (1).

Rezistencija na antibiotike predstavlja rastući problem koji je Svetskazdravstvena organizacija proglasila jednom od najvećih pretnji za globalno zdravljeljudi. Lanac hrane jedan je od najvažnijih puteva prenošenja i širenja rezistencijena antibiotike između populacije rezistentnih i populacije osetljivih komensalnihi/ili patogenih mikroorganizama. Rezistencija na antibiotike može biti urođena, ilistečena putem mutacija ili lateralnog transfera gena. Sa aspekta širenja rezistencijeznačajna je samo rezistencija stečena lateralnim transferom gena. Postoje brojnemetode za detekciju i određivanje prirode rezistencije na antibiotike kod bakterijaizolovanih iz hrane. Neophodno je da metode budu standardizovane i da obezbeđujukonzistentnost i doslednost dobijenih rezultata. Za detekciju fenotipske rezistencijekod bakterija izolovanih iz hrane koriste se metode kojima se određuje minimalnainhibitorna koncentracija antibiotika. U njih spadaju metod mikrodilucije, metoddilucije u agaru i E-testovi. Kvalitativne i semikvantitativne metode koje se čestokoriste kod kliničkih izolata, nisu prigodne za ispitivanje rezistencije na antibiotikekod mikroorganizama izolovanih iz hrane. Kod mikroorganizama kod kojih seutvrdi prisustvo fenotipske rezistencije na antibiotike, određuje se prisustvo gena zarezistenciju. Mikroorganizmi kod kojih se dokaže prisustvo genetskih determinantikoje su povezane sa stečenom rezistencijom na antibiotike, predstavljaju rizik zadiseminaciju rezistencije i među osetljivom populacijom. Mikroorganizmi koji imajukomercijalnu upotrebu, ne bi trebalo da poseduju genetske determinante prenosiverezistencije na antibiotike.

Probiotici se definišu kao živi mikroorganizmi koji, kada se unesu, pokazuju blagotvoranefekat na domaćina. Mnogi sojevi iz roda Lactobacillus imaju status probiotika.Nedostatak gena za prenošenje rezistencije na antibiotike jedan je odključnih uslova kako bi soj dobio GRAS status. Svaki probiotski soj bi trebalo dapreživi pasažu kroz gastrointestinalni trakt, kako bi uspeo da ostvari blagotovorneefekte po domaćina.Materijal za ovo ispitivanje predstavljao je 51 soj laktobacila koji su izolovani izsjeničkog sira.Svi sojevi su ispitivani na rezistenciju na devet antibiotika. Od ukupno 51 soja,šest je pokazalo osetljivost na sve antibiotike, dok je 23 pokazalo prirodnu rezistenciju,koja, kao takva, nije rizična za prenošenje gena. Najčešći profil rezistencijebila je rezistencija na vankomicin i tetraciklin. Od 18 sojeva koji su stekli uslove zadalje ispitivanje, kod devet njih je ispitivana mogućnost preživaljavanja u simuliranimuslovima želuca, odnosno duodenuma. Takođe je ispitivana i antimikrobna aktivnosti sposobnost hemolize. Svih devet sojeva je pokazalo odličnu sposobnostpreživljavanja u simuliranim uslovima želuca, dok je svega tri moglo da preživi uprisustvu žučnih soli. Svih devet sojeva je pokazalo antimikrobnu aktivnost protivListeria monocytogenes i Staphylococcus aureus, a nijedan nije pokazao hemolizu.Prema rezultatima u ovom ispitivanju, sojevi laktobacila izolovani iz sjeničkogsira pokazali su da imaju potencijal da steknu status probiotika, ali su za to potrebnadalja ispitivanja.

This study aimed to characterize Aeromonas spp. isolated from ten popular species of pet turtles and their environment to evaluate the potential risk of pet turtles as a source of virulence-associated genes, and tetracycline and β-lactams resistance determinants. Presence of eight virulence genes (ser, aer, exu, lip, fla, ascV, ahyB and gcat), and tetracycline (tetA, tetB and tetE) and β-lactams (blaTEM, blaSHV, blaOXA and blaCTX-M) resistance genes were evaluated by conventional PCR assays. The aerA gene showed the highest frequency of occurrence (92%), followed by fla (75%), gcaT (68%), ahyB (59%), ser (39%), lip (37%) and ascV (25%) genes. None of the isolates carried amplicon of DNase-associated exu gene. A. hydrophila, A. dharkensis, A. veronii and A. caviae were carried seven tested virulence genes except for exu while only four virulence genes were detected in A. enteropelogenes. Among the 75 tetracycline-resistant isolates, tetA, tetE and tetB genes were detected in 38, 26 and 6 isolates, respectively. Among the tested β-lactam resistance genes, blaOXA and blaTEM genes were detected in 54% and 36% of β-lactam resistant isolates, respectively. No blaCTX-M and blaSHV genes were detected. Our results indicate that pet turtle-associated aeromonads, exhibiting potential virulence and antimicrobial (tetracycline and β-lactams) resistance genes, may pose a serious health risk to pet turtle owners, particularly to immunocompromised individuals.Key words: Aeromonas spp.; virulence-associated genes; tetracycline resistance; β-lactams resistance; pet turtle PRISOTNOST DETERMINANT ZA DOLOČITEV DOMNEVNE VIRULENCE TER GENOV ZA ODPORNOST NA TETRACIKLIN IN β-LAKTAM VRST Aeromonas IZOLIRANIH IZ LJUBITELJSKIH VRST ŽELV IN IZ NJIHOVEGA OKOLJAIzvleček: Namen študije je bil določiti bakterije Aeromonas spp., izolirane iz desetih priljubljenih vrst hišnih želv in njihovega okolja, z namenom ocenjevanja potencialnega tveganje hišnih želv kot vira genov, povezanih z virulenco, ter determinante odpornosti proti tetraciklinom in β-laktamom. Prisotnost osmih virulentnih genov (ser, aer, exu, lip, fla, ascV, ahyB in gcat) ter genov za odpornost na tetracikline (tetA, tetB in tetE) in β-laktame (blaTEM, blaSHV, blaOXA in blaCTX-M) je bila ocenjena s konvencionalnimi testi PCR. Najbolj pogost je bil Gen aerA (92 %), sledili so geni fla (75 %), gcaT (68 %), ahyB (59 %), ser (39 %), lip (37 %) in ascV (25 %). Nobeden od izolatov ni imel pomnoženega gena exu, povezanega z DNAzo. A. hydrophila, A. dharkensis, A. veronii in A. caviae so vsebovali sedem testiranih genov virulence, razen exu, medtem ko so bili v A. enteropelogenih odkriti le štirje virulenčni geni. Med 75 izolati, odpornimi na tetracikline, so bili geni tetA, tetE in tetB odkriti v 38, 26 oziroma 6 izolatih. Med preizkušenimi geni za odpornost proti β-laktamu so bili geni blaOXAin blaTEM odkriti pri 54 % oziroma 36 % izolatov, odpornih proti β-laktamu. V nobenem vzorcu nista bila zaznana gena blaCTX-M in blaSHV. Rezultati študije kažejo, da bakterije Aeromonas spp. iz hišnih želv lahko imajo potencialne virulenčne gene in gene za odpornost proti tetraciklinu in β-laktamom, in lahko potencialno ogrožajo zdravje lastnikov hišnih želv, zlasti imunsko oslabljenih posameznikov.Ključne besede: Aeromonas spp.; geni povezani z virulenco; odpornost na tetracikline; rezistenca na β-laktami; ljubiteljske vrste želv

Colistin, also known as polymyxin E, is antibiotics active against most of Gram-negative bacteria. In the pas decade, emergency of multidrug-resistant bacteria led to increase of colistin administration as a last resort antibiotic for human infections. The first plasmid-mediated colistin resistance gene mcr-1 was identified in 2015 in animals in China and after first detection, additional mcr genes: mcr-2, mcr-3, mcr-4, mcr-5, mcr-6, mcr-7 a mcr-8 were described throughout the world. The aim of this thesis was to clarify whether there is horizontal transmission colistin resistance encoded by the mcr genes in gram-negative bacteria isolated from the environment, animals and their breeding and food. The mcr-1 gene was detected in 2 strains Escherichia coli isolated from waste water. The mcr-4 gene was detected in 1 strain Shewanella putrefaciens isolate obtained from the lake. The environment is the most important source and way of spreading this type of resistance in the Czech Republic.

Colistin is a polypeptide antibiotic used as a "last resort" effective against Gram-negative bacteria. However, increase in its consumption in veterinary medicine in the last 30 years has led to the development of bacterial resistance even to colistin. The application of slurry to soil containing unmetabolized colistin and resistant bacteria poses a risk, because the resistance of bacteria to colistin can be further developed and spread to other components of the environment. Therefore, this work was focused on the creation and optimization of extraction and analytical methods for soil samples containing colistin. Colistin was detected by liquid chromatography in connection with mass spectrometry (HPLC/MS and UPLC/MS/MS). Many extraction solutions have been tested in connection with ultrasonic extraction and purification on various SPE columns, yet colistin has not been successfully extracted from the soil. Colistin was successfully detected only in the slurry extract. The reason why colistin was not detected in soil extracts could be the sorption of colistin on soil organic matter or the formation of complexes of colistin with humic substances.

The thesis deals with a theme of probiotic mikroorganisms which are aplicated as a dietary supplement. Health benefit on the host have been known for a long time, however, there might be some negative effects affecting a consumer. In connection with this observation defining requirements and evaluating of safety of probiotics in food was necessary. The new probiotic dietary supplement can not be expanded on the market without these processes. Every strain must be tested separately on each property. The ability of rezistance against conditions inside human gastrointestinal tract belongs to the most basic tests. The aim of the practical part is testing this ability of rezistance in vitro by simulated conditions. The model of gastrointestinal juices was designed according to the Czechoslovak codex. The form contributes to the higher rezistance of probiotics within implementing to the host. Also a dosage form of probiotics was involved to a in vitro testing.

Bacterial infections caused by pathogenic microorganisms are classified among one of the major global health problems. In recent decades, bacterial resistance to antimicrobials has been seen as a major problem in the human and veterinary fields. The dissertation thesis is focused on the development and evaluation of the biological activity of antimicrobial agents, followed by describing the mechanism of antibiotic resistance from a molecularly microbiologically aspects. In the experimental part the nanomaterials, antimicrobial peptides, antibiotics and also the composites from these materials have been used for development of new antimicrobial agents and subsequently tested for their inhibitory effect on bacterial growth. The synthesized antimicrobials were physically and chemically characterized and their biological activity was established by basic microbiological and molecular methods. The results show that the produced composites can overcome existing drug resistance mechanisms, show excellent biocompatibility, and can be used in clinical practice in the future.

Bacterial infections with complicated process and therefore lengthy, often unsolvable treatment due to emerging resistance to antibiotic drugs are currently increasingly frequent problem of many medical fields. The presented thesis entitled "Effect of heavy metal ions on the biological properties, resistance and virulence" was primarily focused on the study of selected metal ions (Ag +, Cd2+, Cu2+, Pb2+ and Zn2+) on the biochemical properties of bacterial strains, in particular observing their influence on free radical formation, creation of oxidative stress and growth properties. Detection of the influence of metals not only on biochemical parameters, but mainly their significant antimicrobial effect directed our further studies to testing of antimicrobial activity of metals (usually silver) or metal nanoparticles synthesized in complexes with polymer substances (chitosan, hyaluronic acid). The obtained results clearly showed the nanoparticles as the best form, so the effects of proven antimicrobial silver nanoparticles were subsequently compared with metalloid selenium nanoparticles, which even surpassed the previous results of antimicrobial activity. Finally, the effect of long-term action of metal ions on the emerging resistance or so-called multiresistance in the case of cross-resistance of metals and antibiotic drugs was tested.

The presence of infections caused by Staphylococcus aureus (S. aureus) and its resistant form - methicillin-resistant S. aureus (MRSA) - are more frequent and treatment with increasing resistance becomes increasingly complicated. Early identification of microbiome in the infectious wounds leads to implementation of the correct treatment and thereby saving the patient from the formation of abscesses, amputation of limbs or even death. Presented thesis entitled Progressive tools for the identification of Staphylococcus aureus is focused on the study of the occurrence of these bacteria in clinical samples, design and construction of new detection methods based on magnetic separation and evaluation of the effects of antibiotics and metal nanoparticles on growth and biofilm formation, gene expression and protein composition in S. aureus and MRSA. The most abundant microorganism in microbiome of infections is S. aureus and in our studies was used as model bacteria for the design of fast, accurate and sensitive detection techniques utilizing indirect detection such as: i) detection of product of biochemical reaction between bacterial enzymes and matrix, ii) detection of the amplified gene using gold nanoparticles as an indicator probe, iii) determination of the detection oligonucleotides after sandwich capture of bacteria between micro and nanoparticles, and iv) a multiplex detection of quantum dots using sandwich capture of specific gene from selected bacteria. Subsequently, an influence effect of beta-lactam antibiotics and their complexes with selenium nanoparticles to non-resistant and resistant form of S. aureus was investigated. The significant inhibition of bacterial growth and biofilm formation as well as changes in gene expression and protein composition were achieved in MRSA by using the complexes of antibiotics and selenium nanoparticles.

This diploma thesis deals with resistance of microorganisms to antibiotics and public awareness of this topic. The aim of the thesis was to find out what the public awareness of the given topic is and what knowledge the public has about the possibilities of prevention of creation and spreading of resistant microorganisms. Three main hypotheses have been set: Hypothesis 1: The public has no deeper knowledge of antibiotic treatment. Hypothesis 2: The public will in most cases get information on antibiotic treatment from a doctor. Hypothesis 3: Most people are unaware that they can contribute by rational use of antibiotics to prevent antibiotic resistance. In order to achieve the stated goals of the diploma thesis, a quantitative method of research was used. Data collection was conducted through anonymous questionnaire survey of the public population using the Click4Survey.cz web server and distribution of paper questionnaires in FN Plzeň. Results of the questionnaire survey were evaluated based on statistical data processing in Microsoft Office Excel 2007, and a Chi-squared test of independence in the pivot table and a relative frequency test were used to verify the hypotheses. Based on the evaluation of the results, it was found that among the groups of respondents, depending on whether they filled in a questionnaire on the Internet or a printed questionnaire at the hospital, there are fundamental statistical differences in knowledge and awareness of the problem. That is why it was necessary to further evaluate these two groups separately. Antibiotic resistance nowadays is a very important medical issue. The main cause is inconsistent use or overuse of antibiotics in both human and veterinary medicine, as well as insufficient awareness of the extent of the problem and the consequences of antibiotic resistance. For this reason, I have chosen this issue as a topic for my diploma thesis to highlight the risks of antibiotic resistance and to provide information primarily to the general public.

Charles University Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Study program: Specialist on Laboratory Methods Autor: Bc. Marcela Vízková Supervisor: PharmDr. Ondřej Janďourek, Ph.D. Title: In vitro screening of novel potentially active antibacterial compounds III Since the discovery of penicillin, antibiotics have become part of modern therapeutic approaches. But the global spread of resistance makes their future uncertain. It is necessary to find new antibacterial substances useful in practice. As resistance is a global threat, the theoretical part deals with this issue. In addition to resistance, the theoretical part also briefly describes the antibiotics used, including new antibiotics, which were recently registered or likely to be registered. For selected groups, their mechanism of action is described in detail. Sensitivity should be determined to correctly indicate the antibiotic treatment. For this reason, the theoretical part also describes methods by which the sensitivity of a microbe to an antibiotic can be determined qualitatively or quantitatively. The theoretical part does not neglect the history of the development of antibacterial substances and familiarization with antibiotic policy in the Czech Republic. This diploma thesis is based on...