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1
Renault, Agnes J. "Formulary status of cephalosporins." Scholarly Commons, 1987. https://scholarlycommons.pacific.edu/uop_etds/498.
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The primary purpose of this study is to analyze the formulary status of cephalosporins among a representative sample of hospitals in the United States. In addition, the research design attempts to determine the ranking of cephalsoporins in terms of acceptance to the hospitals' formulary and actual stocking of the cephaosoporin products. The study will attempt to ascertain the reasons for these rankings and the influence of DRG implementation, teaching status and hospital bed size on number of cephalosporins on formulary and in stock. This may yield insight into the strategies that hospitals are currently using to contain a significant proportion of their budget for pharmaceutical products
2
LlinaÌ€s, MartiÌ Antonio J. "Chemical reactivity of penicillins and cephalosporins." Thesis, University of Huddersfield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273731.
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Kythreoti, Georgia. "Green Routes to the Synthesis of Cephalosporins." Thesis, University of Manchester, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492767.
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This thesis is concerned with studies on the enzyme carbamoyl transferase (CT) of the C cephalosporin intermediate (7-adipoyl-3-carbamoyloxymethyl cephalosporin) is an important step towards the demonstration of a novel and efficient bioprocess to make this intermediate.
4
Lloyd, Christopher T. "New routes to some substituted penicillins and cephalosporins." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/15227.
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Literature methods for the synthesis of benzyl 6-oxo-penicillanate have been studied, it was apparent that some of these reports contained conflicting information with regards to reaction conditions and yields. The same methodology was also used to synthesise the cephalosporin analogue t.butyl7-oxocephalosporanate. The reactions of these compounds with various trimethylsilyl amides and with the Wittig reagent 5'triphenylphosphoranylidenecyclohexanespiro-2'-(1',3'dioxolan)-4'-one have been investigated. The potential for attaching penicillin and cephalosporin nuclei to polymer supports, and thereby utilising the well developed methodology of solid phase peptide synthesis in the field of the discovery of novel β-lactam compounds, has been investigated. Difficulties were encountered when attempting to remove the β-lactams from the resin, however both penicillin and cephalosporin compounds were recovered, in low yield, having had the 6β-(7β-) amino protecting group changed whilst attached to the resin.
5
Hill, Ryan Lee. "Studies on the enzymatic conversion of pencillins and cephalosporins." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318789.
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Cheung, Kai Yan Keith. "Directed evolution towards the production of penicillins and cephalosporins." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542790.
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Buckwell, S. C. "The kinetics of the #beta#-lactamase catalysed hydrolysis of cephalosporins." Thesis, University of Huddersfield, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376437.
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Challis, Gregory Leonard. "Studies on the biosynthesis of antimicrobial natural products." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390494.
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Wood, Mark Elliott. "Studies in enzyme reaction mechanisms." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.256394.
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Arezi, Bahram. "Mutational analysis of ACV synthetase in fungi." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265916.
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Barrett, Martin Andrew. "Transport of cephalosporins across monolayers of some human epithelial cell lines." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300009.
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Hewinson, R. G. "#BETA#-Lactamase-mediated resistance to '#beta#-lactamase-stable' cephalosporins in Pseudomonas aeruginosa." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382716.
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13
Channing, Sally E. "In vitro activity of cephalosporins against selected gram negative bacilli : [a thesis]." Scholarly Commons, 1987. https://scholarlycommons.pacific.edu/uop_etds/496.
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The in vitro activity of twelve cephalosporins (first generation: Cephalothin, Cefazolin; second generation: Cefoxitin, Cefamandole, Cefuroxime, Cedonicid; third generation: Ceftazidime, Ceftizoxime, Cefotaxime, Cefoperazone, Ceftriaxone, Moxalactam) were studied against 146 strains of Gram negative bacilli belonging to the following families: Enterobacteriaceae Proteus vulgarius (2), P. mirabilis (5), Providencia stuartti (6), P. alkalifaciens (5), Morganella morganii (16), Serratia marcescens (14), Enterobacter cloacae (17), E. aerogenes (9), Kluyvera ascorbata (3), Citrobacter freundii (14), C. diversus (3), C. amalonaticus (1), Yersinia intermedia (1), Y. enterocolitica (2); Pseudomonadaceae: Pseudomonas aeruginosa (31), P. fluorescens (3); Neisseriacaee: Acinetobacter anitratus (3), Acinetobacter lwoffi (1); and Vibrionaceae: Aeromonas hydrophilia (4), Plesiomonas shigelloides (1), Campylobacter jejuni (5)). This investigation, which studied the activity of all the mentioned cephalosporins against each strain, suggests that resistance to the third generation cephalosporins has already emerged in such species as S. marcescens, E. cloacae, E. aerogenes, C. freundii, P. aeruginosa, P. fluorescens, A. anitratus, A. lwoffi, and Campylobacter jejuni. This resistance is most pronounced in Enterobacter spp., Serratia marcescens, and Pseudomonas aeruginosa. The second generation cephalosporins, particularly Cefoxitin and perhaps Cefuroxime, are chief inducers of resistance in Enterobacter and Serratia. In the pseudomonads difference mechanisms seem to operate than those taking place in Enterobacter-Serratia. The study also shows that resistance is not a generic characteristic in Proteus, Providencia, or Citrobacter but rather specific. Some aspects of mechanisms of resistance to cephalosporins are discussed. Concern is here indicated that at least in certain groups of bacteria, the use of the second generation cephalosporins may lead to emergence of resistance to the third generation group.
14
Apostolakos, Ilias. "Bacterial resistance to third-generation cephalosporins and colistin in the poultry industry." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3425776.
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Antimicrobial resistance is one of the major public health threats that humans face with a significant number of annual deaths and economic losses from associated sequelae. Presence of resistance determinants in food-producing animals represents an important exposure risk since they can be transmitted to humans by direct contact or via the food chain. Among the various types of resistance already described in poultry, resistance to critically important antimicrobials, such as third-generation cephalosporins (3GCs) and colistin, is worrying due to the crucial role of these antimicrobials in severe infections encountered in health care settings. The high levels of resistance to 3GCs previously described in broilers, led to the belief that the broiler production may act as a reservoir of 3GC resistance determinants. Therefore, Chapters 2-4 aimed to investigate their presence, characteristics, transmission patterns and identify intervention measures for risk mitigation strategies. In light of the alarming emergence of mobile colistin resistance mechanisms, Chapter 5 undertook a review on their global distribution in the poultry industry and addressed the current situation and challenges of colistin resistance.
The structure of the thesis is: (i) general introduction, (ii) four main chapters of research articles either published, in press or in preparation, (iii) overall conclusion, (iv) additional information for each of the main chapters, (iv) two appendices with contribution to other research work, (v) acknowledgements, and (vi) the literature cited.La resistenza agli antimicrobici è uno dei principali problemi di sanità pubblica, a causa dell’elevato numero di morti e di perdite economiche che si verificano annualmente. La presenza di determinanti di resistenza negli animali produttori di alimenti rappresenta un importante rischio per l’uomo, per la possibile trasmissione per contatto diretto o attraverso la catena alimentare. Tra i vari tipi di resistenza già descritti nelle specie avicole, la resistenza ad antimicrobici criticamente importanti, quali le cefalosporine di terza generazione (3GC) e la colistina, è particolarmente preoccupante a causa del ruolo cruciale che questi antimicrobici assumono a livello nosocomiale nel trattamento di infezioni gravi. Gli elevati livelli di resistenza alle 3GC già decritti nei broiler hanno indotto a ritenere che la filiera produttiva del pollo da carne possa fungere da reservoir di determinanti di resistenza nei confronti di 3GC. Pertanto, i Capitoli 2-4 riportano i risultati di studi condotti allo scopo di investigare la loro presenza, le loro caratteristiche, la loro modalità di trasmissione e di identificare misure correttive per la mitigazione del rischio. Alla luce dell’allarmante comparsa di meccanismi di trasferimento della resistenza nei confronti della colistina, il Capitolo 5 riporta una review sulla sua distribuzione nell’industria avicola a livello globale, soffermandosi in particolare sull’attuale situazione e sulla minaccia che essa rappresenta. La tesi è suddivisa in: (i) introduzione generale, (ii) quattro capitoli riguardanti articoli già pubblicati, in via di pubblicazione o in preparazione, (iii) conclusione generale, (iv) informazione aggiuntiva per i principali capitoli, (iv) ringraziamenti, e (v) citazioni bibliografiche.
15
Crouch, Nicholas. "The mechanism of the enzymatic ring expansion of penicillin N to deacetoxycephalosporin C." Thesis, University of Oxford, 1988. http://ora.ox.ac.uk/objects/uuid:de3e54eb-b4b5-4673-a863-3c094cc1456d.
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The order of events in the Deacetoxycephalosporin C/Deacetylcephalosporrn C Synthetase (DAOC/DAC Synthetase) catalysed ring expansion of penicillin N to deacetoxycephalosporin C has been investigated by the use of labelled/unlabelled penicillin N mixed competitive kinetic isotope effect experiments, in which the labelled penicillin N substrates were either labelled in the pro R- and pro S-methyl groups or at C-3. In addition, to assisting in the determination of the position of the first irreversible event in this reaction, deuteration at C-3 gave rise to a bifurcation of the natural biosynthetic pathway which led to enhanced production of the shunt metabolite, (2R,3S,6R,7R)-l-aza-3- methyl-3-hydroxy-7-[(5R)-5-amino-5-carboxy-pentanamido]-8-oxo-5-thiabicyclo[4.2.0]octane-2-carboxylate. The biosynthetic precursor to the 3S-hydroxycepham shunt metabolite has been investigated and the origin of the 3S-hydroxyl oxygen atom has been determined by the use of labelling studies with 18O2 and shown to be derived from molecular oxygen. 13C-labelling studies are described which indicate that the ring expansion process is stereospecific to within the limits of the detection system employed. These experiments confirm earlier investigations but, in addition to improving upon the assessment of the degree of stereospecificity, have shown that the 3S- hydroxycepham shunt metabolite is produced with the same stereospecificity as that observed for the usual biosynthetic products, DAOC and DAC. Chapter 5 describes an investigation of the anomalous C-2 deuterium exchange detected in DAOC produced by incubation of di-(2H3-methyl)-penicillin N with DAOC/DAC synthetase. The preliminary results from this study indicate that initially exchange occurs stereospecifically with the pro R C-2 deuterium atom being replaced by a hydrogen atom. The origins of the unusual tripeptides L-α-aminoadipyl-L-serinyl-D-valine (L,L,D-ASV), α-aminoadipyl-serinyl-isodehydrovaline (ASdV) and α-aminoadipyl-cysteinyl- β-hydroxyvaline (AC-[β-OH]-V) isolated from Penicillium chrysogenum and Cephalosporium acremonium, have been examined by the use of variously 13C-labelled L,L,D-α-aminoadipyl-cysteinyl-valine (L,L,D-ACV) and D,L,D-α-aminoadipyl- cysteinyl-valine (D,L,D-ACV) tripeptide isotopomers. The initial results obtained from this investigation may be considered as circumstantial evidence that ASdV is formed by the action of IPNS upon L,L,D-ACV. Finally, various substrate analogues have been prepared and evaluated as substrates for the ring expansion and hydroxylation activities of the bifunctional DAOC/DAC synthetase enzyme.
16
Shallouf, Mohamed Abdusalam. "Identification and characterisation of cephalosporins and carbapenem-resistant Klebsiella pneumoniae isolates from Misrata, Libya." University of the Western Cape, 2018. http://hdl.handle.net/11394/6512.
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Philosophiae Doctor - PhDBackground: Extended-spectrum beta-lactamase-producing (ESBL) and carbapenemaseproducing Gram-negative bacilli showing resistance to cephalosporins and carbapenems respectively, have been reported from several countries globally and recently among Libyan combatants who have been transferred to European countries for advanced medical care. However, there is a lack of data about their presence in Misrata and in Libya in general. This is the first documented study aimed at investigating the prevalence and resistance mechanisms of ESBL and carbapenemase-producing K. pneumoniae isolates from Misrata. Materials and Methods: Two hundred Gram-negative bacillus isolates were collected and identified from hospitals and pathology laboratories in Misrata. Following antimicrobial susceptibility screening, those showing resistance to cephalosporin and carbapenem were tested for ESBL activity using the Modified double disc synergy test, Sensititer ESBL confirmatory MIC plates and MAST AmpC detection sets D52C and D68C. Carbapenemase activity was detected using RAPIDEC CARBA NP test, Modified Hodge test (MHT), carbapenem inactivation methods (CIM), carbapenem combined test (CCT), and by MAST carba puls set. ESBL and carbapenemases genes were detected using multiplex PCR. Results: K. pneumoniae was the predominant species (85/200) of the 14 species identified, with 56 (65.8%) showing carbapenem resistance, 16 (18.8%) were cephalosporin-resistant carbapenem-susceptible and 13 (15.2%) were susceptible to all antibiotics except ampicillin. OXA-48 was the only carbapenemase detected, with SHV, TEM and CTX-M group 1 found in almost all carbapenem and cephalosporin resistant K. pneumoniae. Rep-PCR analysis revealed multiple clones and some K. pneumoniae strains were genetically related or indistinguishable despite differences in ESBL genes or carbapenemase activity. Conclusion: The findings of this study show that carbapenemase- and ESBL-producing K. pneumoniae are prevalent in Misrata and emphasize the urgent need for optimized infection control and antibiotic stewardship programmes in the Libyan hospitals to prevent further spread of these organisms.
17
Miropolskiy, Reuven. "The effects of soil properties on the sorption of selected cephalosporin antibiotics." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/r_miropolskiy_120109.pdf.
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Thesis (M.S. in chemical engineering)--Washington State University, December 2009.Title from PDF title page (viewed on Jan. 20, 2010). "Department of Chemical Engineering and Bioengineering." Includes bibliographical references (p. 63-65).
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Pereira, Inês Antunes Cardoso. "Studies on deacetoxy/deacetylcephalosporin C synthase." Thesis, University of Oxford, 1993. http://ora.ox.ac.uk/objects/uuid:d00c6130-a9ec-44f8-a1f5-0465dbaeb4f9.
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This thesis describes an investigation of the mechanism of the bifunctional, a-ketoglutarate dependent dioxygenase, deacetoxy/deacetylcephalosporin C synthase (DAOC/DACS), which catalyses the ring-expansion of penicillin N to deacetoxycephalosporin C (DAOC) and the hydroxylation of this to deacetylcephalosporin C (DAC). The conversion of the unnatural substrate 3-exomethylene cephalosporin C by DAOC/DACS has been investigated in detail. A new metabolite was isolated from incubations of the deuterated [4-2H]-3-exomethylene cephalosporin C, and was identified as the 3β-spiroepoxide cepham, (2Ṟ,3Ṟ,6Ṟ,7Ṟ)-l-aza-[2-2H]-3-spiroepoxy-7-[(5Ṟ)-5-amino- 5-carboxypentanamido]-8-oxo-5-thiabicyclo[4.2.0]octane-2-carboxylic acid. The results obtained indicate that this metabolite is a shunt product whose formation is enhanced by the operation of a deuterium kinetic isotope effect on an enzyme-bound intermediate. It has also been found that this 3β-spiroepoxide cepham is further converted by DAOC/DACS to 3-formyl cephalosporoate products. The mechanism of oxygenation of DAOC/DACS was investigated through 18O-labelling studies. Incubations of [2-13C,3-2H]penicillin N and [4-2H]-3-exomethylene cephalosporin C with DAOC/DACS were carried out under 18O2 or in H218O. Incorporation of 18O-label into the products [3-13C]DAC, [3-13C,4-²H]-3β-hydroxycepham and 3β-spiroepoxide cepham was observed from both sources. The results suggest that intermediates capable of oxygen-exchange are formed during the enzymatic reactions. Two substrate analogues, the 5-epipenicillin N and the 2β-difluoromethyl penicillin N, have been synthesised in order to probe the substrate specificity of DAOC/DACS with respect to the ring-expansion activity. The 5-epipenicillin N was not accepted as a substrate by DAOC/DACS, and the observations made indicate that it was unstable under the incubation conditions. No product was either observed from incubations of the 2β-difluoromethyl penicillin N with DAOC/DACS, although bioassay tests suggested a cephem product had been formed in very small amounts. Finally, the results of a substrate specificity comparison between the soluble recombinant enzymes deacetoxy/deacetylcephalosporin C synthase (DAOC/DACS) from Cephalosporium acremonium and deacetoxycephalosporin C synthase (DAOCS) from Streptomyces clavuligerus are described.
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Kadurugamuwa, Jagath L. "Influence of sub-inhibitory concentrations of cephalosporins on surface properties of klebsiella pneumoniae important in infection." Thesis, Aston University, 1985. http://publications.aston.ac.uk/12489/.
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Mackenzie, Alasdair. "Studies on the biosynthetic pathways of clavulanic acid and cephamycin C in Streptomyces clavuligerus /." Uppsala : Department of Molecular Biology, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200719.pdf.
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Kleinhenz, Katie Elizabeth. "The Impact of Ceftiofur Removal on Recovery of Salmonella enterica and Escherichia coli Resistant to Third Generation Cephalosporins." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1357225078.
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Du, Bois Stephen Keith. "The effects of changes in structure of plasmid-encoded β-lactamases on the binding of third-generation cephalosporins." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/20941.
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The gene encoding TEM-E2 (blaT-E2), an ESBL identified in an isolate of Klebsiella oxytoca responsible for an outbreak of infection in a neonatal unit in Liverpool in 1982, was sequenced. As cloning from PCR-amplified DNA fragments proved difficult, a new technique for direct DNA-sequencing of PCR-amplified DNA fragments was developed. From the sequences of blaT-E2pUK721 generated by this method, a new nucleotide was identified at DNA residue number 691, corresponding to adenosine. Biochemical experiments and PCR studies showed that the gene for TEM-E2 was present in addition to TEM-1. No additional bands were visible in the same regions of TEM-1 control sequences produced by the same method. In conclusion: Conservative mutations or mutations remote from the active site do not affect biological parameters in a measurable manner. Evolutionary implications of the single mutations may be relatively minor and may not be detected during the normal course of events. Silent mutations, or minimally important mutations, occur frequently with little functional consequence but may prepare bacteria to be ready for a more drastic change when challenged with a 3GC. Acquisition of a single innocuous mutation facilitates the occurrence of a more dangerous double mutation. The results suggest that clavulanic acid, in combination with amoxycillin, promotes back mutations from extended-spectrum β-lactamases to TEM-1 by a mechanism of gene duplication facilitated by intermolecular transposition. I have suggested the hypothesis that the evolution of the parent β-lactamase to broad-spectrum enzyme can consist of both forward and backward mutations at well defined locations. This hypothesis is supported by my results which show that amoxycillin in combination with clavulanic acid selects back mutations to TEM-1 and other extended-spectrum β-lactamases. The back mutations are facilitated by gene duplication. The host organism will also contain a heterogeneous population of a clinical plasmid. The point-mutations occur in the TEM-gene during duplication of the gene. In a non-selective environment one of the duplicate genes is usually deleted.
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Pedroso, Tahisa Marcela [UNESP]. "Análise químico-farmacêutica de cefazolina sódica em pó liofilizado para solução injetável." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/91679.
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Os antimicrobianos têm um papel fundamental no controle de doenças infecciosas. As cefalosporinas se mantêm como uma classe de antimicrobianos que se sobressaem pela sua importância terapêutica, elevada frequência de utilização, segurança e efetividade contra um amplo espectro microbiano. A cefazolina sódica (CFZ) é um agente antimicrobiano β-lactâmico, classificada como cefalosporina de primeira geração, muito utilizado como agente terapêutico e na profilaxia perioperatória. Neste trabalho foram desenvolvidos novos métodos analíticos para análise qualitativa e para a quantificação de cefazolina sódica, visando a obtenção de métodos mais rápidos, mais seguros para os operadores, mais econômicos e de fácil execução, que são essenciais para a análise desta cefalosporina na indústria farmacêutica. Na análise qualitativa, a cefazolina foi estudada quanto a sua solubilidade, ponto de fusão, pH, espectrofotometria na região do ultravioleta (UV) e na região de infravermelho (IV), cromatografia em camada delgada e cromatografia líquida de alta eficiência (CLAE), possibilitando a identificação da amostra. Para quantificação do fármaco três métodos foram validados. O método espectrofotométrico na região do ultravioleta foi validado utilizando o comprimento de onda de 270 nm, com faixa linear de concentração de 8 a 28 μg/mL utilizando água purificada como solvente, o teor foi de 99,10% e a exatidão foi de 100,56%. Ensaio microbiológico por método turbidimétrico utilizou o micro-organismo Staphylococcus aureus ATCC 26923, com faixa linear de 6 a 11,46 μg/mL e apresentou potência de 100,07% e exatidão foi 99,92%. A validação do método por CLAE foi realizada empregando fase móvel composta por água purificada e acetonitrila (60:40 v/v), com pH 8 ajustado com trietilamina (TEA), no comprimento de onda...
The antimicrobials have a crucial role in the control of infectious diseases. Cephalosporins remain one class of antimicrobials that stand out for their therapeutic importance, high frequency of use, safety and effectiveness against a broad microbial spectrum. Cefazolin sodium (CFZ) is a β-lactam antimicrobial agent, classified as first-generation cephalosporin, often used as a therapeutic agent and for perioperative prophylaxis. In this work, new analytical methods were developed for qualitative and quantitative analysis of cefazolin sodium in lyophilized powder, seeking obtain method faster, safer for operators, more economical and easiness of implementation, which are essential for the analysis of this cephalosporin in pharmaceutical industry. For qualitative analysis, several methods were performed, including analyzes of solubility, melting point and pH; ultraviolet (UV) and infrared (IR) spectrophotometry; thin layer chromatography and high performance liquid chromatography (HPLC) allowing the identification of samples. For quantification of the drug, three analytical methods were validated. The spectrophotometric method in the ultraviolet region was validated at 270 nm, with a linear range of concentration from 8 to 28 mg/mL, using purified water as solvent, the content of 99.10% accuracy of 100.56%. In the microbiological assay by turbidimetric method, Staphylococcus aureus ATCC 26923 was used as microrganism test, with linear range from 6 to 11.46 mg/mL, the method presented potency of 100.07% and accuracy of 99,92%. Validation of the HPLC method consisted of mobile phase composed of purified water and acetonitrile (60:40 v/v), adjusted to pH 8 with triethylamine (TEA), and detection wavelength of 270 nm, yielding a retention time of 3.6 minutes in the linear range evaluated from 30 to 80 μg/mL, content... (Complete abstract click electronic access below)
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Pedroso, Tahisa Marcela. "Análise químico-farmacêutica de cefazolina sódica em pó liofilizado para solução injetável /." Araraquara, 2013. http://hdl.handle.net/11449/91679.
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Orientador: Hérida Regina Nunes SalgadoBanca: Armando da Silva Cunha Junior
Banca: Marlus Chorilli
Resumo: Os antimicrobianos têm um papel fundamental no controle de doenças infecciosas. As cefalosporinas se mantêm como uma classe de antimicrobianos que se sobressaem pela sua importância terapêutica, elevada frequência de utilização, segurança e efetividade contra um amplo espectro microbiano. A cefazolina sódica (CFZ) é um agente antimicrobiano β-lactâmico, classificada como cefalosporina de primeira geração, muito utilizado como agente terapêutico e na profilaxia perioperatória. Neste trabalho foram desenvolvidos novos métodos analíticos para análise qualitativa e para a quantificação de cefazolina sódica, visando a obtenção de métodos mais rápidos, mais seguros para os operadores, mais econômicos e de fácil execução, que são essenciais para a análise desta cefalosporina na indústria farmacêutica. Na análise qualitativa, a cefazolina foi estudada quanto a sua solubilidade, ponto de fusão, pH, espectrofotometria na região do ultravioleta (UV) e na região de infravermelho (IV), cromatografia em camada delgada e cromatografia líquida de alta eficiência (CLAE), possibilitando a identificação da amostra. Para quantificação do fármaco três métodos foram validados. O método espectrofotométrico na região do ultravioleta foi validado utilizando o comprimento de onda de 270 nm, com faixa linear de concentração de 8 a 28 μg/mL utilizando água purificada como solvente, o teor foi de 99,10% e a exatidão foi de 100,56%. Ensaio microbiológico por método turbidimétrico utilizou o micro-organismo Staphylococcus aureus ATCC 26923, com faixa linear de 6 a 11,46 μg/mL e apresentou potência de 100,07% e exatidão foi 99,92%. A validação do método por CLAE foi realizada empregando fase móvel composta por água purificada e acetonitrila (60:40 v/v), com pH 8 ajustado com trietilamina (TEA), no comprimento de onda... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The antimicrobials have a crucial role in the control of infectious diseases. Cephalosporins remain one class of antimicrobials that stand out for their therapeutic importance, high frequency of use, safety and effectiveness against a broad microbial spectrum. Cefazolin sodium (CFZ) is a β-lactam antimicrobial agent, classified as first-generation cephalosporin, often used as a therapeutic agent and for perioperative prophylaxis. In this work, new analytical methods were developed for qualitative and quantitative analysis of cefazolin sodium in lyophilized powder, seeking obtain method faster, safer for operators, more economical and easiness of implementation, which are essential for the analysis of this cephalosporin in pharmaceutical industry. For qualitative analysis, several methods were performed, including analyzes of solubility, melting point and pH; ultraviolet (UV) and infrared (IR) spectrophotometry; thin layer chromatography and high performance liquid chromatography (HPLC) allowing the identification of samples. For quantification of the drug, three analytical methods were validated. The spectrophotometric method in the ultraviolet region was validated at 270 nm, with a linear range of concentration from 8 to 28 mg/mL, using purified water as solvent, the content of 99.10% accuracy of 100.56%. In the microbiological assay by turbidimetric method, Staphylococcus aureus ATCC 26923 was used as microrganism test, with linear range from 6 to 11.46 mg/mL, the method presented potency of 100.07% and accuracy of 99,92%. Validation of the HPLC method consisted of mobile phase composed of purified water and acetonitrile (60:40 v/v), adjusted to pH 8 with triethylamine (TEA), and detection wavelength of 270 nm, yielding a retention time of 3.6 minutes in the linear range evaluated from 30 to 80 μg/mL, content... (Complete abstract click electronic access below)
Mestre
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Cole, Michelle Jayne. "Extended-spectrum β-lactamases and Neisseria gonorrhoeae : pre-empting a mechanism that could abolish cephalosporins for the treatment of gonorrhoea." Thesis, University of Portsmouth, 2015. https://researchportal.port.ac.uk/portal/en/theses/extendedspectrum-lactamases-and-neisseria-gonorrhoeae(a32240b8-c498-4dc3-b276-6491bbc32bf2).html.
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Neisseria gonorrhoeae is a public health concern due to increasing numbers of cases of gonorrhoea and the ability of the organism to develop antimicrobial resistance. N. gonorrhoeae can harbour β-lactamase plasmids that encode TEM-1 penicillinase, but do not produce extended spectrum β-lactamases (ESBLs). ESBLs are active against the last remaining option for gonorrhoea monotherapy, ceftriaxone. The aim of this research was to establish what resistance mechanisms in N. gonorrhoeae could abolish the effectiveness of ceftriaxone for the treatment of gonorrhoea. Investigations into the genetic diversity of blaTEM alleles in gonococcal isolates from 2012 detected a high proportion of blaTEM-135 alleles (27%). Only a single specific mutation near the β-lactamase active site could result in TEM-135 penicillinase evolving into an ESBL. Electroporation was established for the transformation of native gonococcal resistance plasmids into N. gonorrhoeae, and was then used in attempts to transfer the enteric plasmid pEK204 (harbouring blaCTX-M-3 and blaTEM-1) into gonococcal strains. Electroporation and natural transformation were additionally used to transform gonococci with blaCTX-M-3 and blaTEM-10 genes. Five transformants were detected using blaTEM-10 and these all showed increased minimum inhibitory concentrations of ceftriaxone. The lack of success in uptake of pEK204 and blaCTX-M-3 was probably due to large plasmid size and lack of recombination site, respectively. Nevertheless, gonococcal β-lactamase plasmids were successfully transferred into clinical strains of the multidrug-resistant clone N. gonorrhoeae ST1407, suggesting that this could also happen in natural mixed gonococcal infections. In summary, it is encouraging that no further blaTEM alleles were detected and that N. gonorrhoeae was not able to express a CTX-M-type ESBL. However, the expression of TEM-10 ESBL is concerning and this work is the first report of ESBL activity in gonococci, albeit in vitro. It is essential to continue antimicrobial susceptibility surveillance and to develop molecular surveillance to detect rapidly the emergence of an ESBL in N. gonorrhoeae.
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Ribeiro, Alyson Rogerio [Verfasser], and Torsten Claus [Akademischer Betreuer] Schmidt. "Fate and effects of two veterinarian cephalosporins, ceftiofur and cefapirin, in the aquatic environment / Alyson Rogerio Ribeiro ; Betreuer: Torsten Claus Schmidt." Duisburg, 2018. http://d-nb.info/1164376489/34.
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Salazar, Ana Sofia Leal Marques Oliveira. "Estudo da resistência às cefalosporinas de terceira geração de isolados de Escherichia coli de origem canina." Master's thesis, Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária, 2011. http://hdl.handle.net/10400.5/3696.
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Dissertação de Mestrado Integrado em Medicina VeterináriaA resistência a antibióticos em Escherichia coli é um problema crescente a nível global, em humanos e animais. Antibióticos criticamente importantes (CI) são aqueles que vão de encontro aos critérios da OMS 1 (única ou uma das poucas terapêuticas disponíveis para tratar infecções graves em humanos) e 2 (antibacterianos utilizados para tratar doenças provocadas por microrganismos que podem ser transmissíveis por fontes não-humanas ou doenças causadas por organismos que podem adquirir genes de resistência de fontes não-humanas). O objectivo deste estudo foi de avaliar taxa de colonização com E. coli resistente a antibióticos em cães saudáveis, particularmente às cefalosporinas de terceira geração. Foram isoladas 135 E. coli de canídeos (n=151) no período de Novembro de 2010 a Janeiro de 2011, no Hospital Veterinário da Tapada. Os cães incluídos no estudo eram saudáveis e não tinham história de consumo de antibióticos no mês anterior à colheita da amostra. As zaragatoas foram inoculadas em água peptonada e incubadas 18horas, sendo depois semeadas em agar MacConkey com um disco de cefotaxima 30μg. Foram seleccionadas colónias típicas de E. coli, preferencialmente as que cresciam junto ao disco, e identificadas pelo método de PCR gadA/B, específico para E. coli. Os testes de susceptibilidade e a sua interpretação foram realizados de acordo com os critérios CLSI. Existiam 51% isolados totalmente susceptíveis, e 49% tinham pelo menos uma resistência adquirida. A prevalência de resistência da E. coli à amoxicilina (Aml) foi de 43%, ao trimetoprim/sulfametoxazol (Sxt) 30%, à cefoxitina (Fox) 25%, à amoxicilina/ácido clavulânico (Amc) 24%, à cefotaxima (Ctx) 18%, à enrofloxacina (Enr) 16% e à gentamicina (Cn) 4%. Multirresistência, definida como resistência a três ou mais classes de antibióticos, estava presente em 23 isolados (17%). Dentro dos isolados multirresistentes, existia resistência a classes de antibióticos criticamente importantes: 17 isolados eram resistentes à cefotaxima e 21 à enrofloxacina. Os perfis mais frequentes de multirresistência eram Amc-Aml-Ctx-Enr-Fox-Sxt (n=9) e Aml-Ctx-Enr-Sxt (n=3). Entre as estirpes de E. coli, 3,7% (n=5) eram produtoras de ESBL (“Extended Spectrum Betalactamases”), possuindo o gene blaCTX-M. Neste estudo foi demonstrado que existe uma frequência elevada de resistência em estirpes de E. coli isoladas de cães saudáveis. Estes resultados mostram que estirpes de E. coli multirresistentes e produtoras de ESBL estão a aumentar e podem comprometer a eficácia terapêutica. Além disso, a resistência às classes de antibióticos criticamente importantes é relevante. É da máxima importância preservar a utilidade destes agentes antibacterianos, já que a resistência teria um impacto relevante na saúde humana devido ao contacto próximo entre animais de companhia e os seus donos. Palavras-chave: Cefalosporinas de terceira geração, resistência, ESBL, cães saudáveis.
ABSTRACT – STUDY OF THIRD GENERATION CEPHALOSPORIN’S RESISTANCE IN ESCHERICHIA COLI ISOLATES OF CANINE ORIGIN - Antimicrobial resistance among Escherichia coli is an increasing global problem in humans and animals. Critically important (CI) antimicrobials are those that met WHO criteria 1 (Sole therapy or one of few alternatives to treat serious human disease) and 2 (Antibacterial used to treat diseases caused by organisms that may be transmitted via non-human sources or diseases causes by organisms that may acquire resistance genes from non-human sources). The aim of this study was to determine the rate of colonization with antimicrobial resistant E. coli particularly to 3rd generation cephalosporins (3GC) among healthy dogs. One-hundred and thirty-five E. coli were isolated from dogs (n=151), between November 2010 and January 2011, at Hospital Veterinário da Tapada. The dogs included in the study were healthy with no history of antimicrobial consumption in the month before they were sampled. Swabs were inoculated in peptone water and incubated 18h and then sub-cultured onto MacConkey agar with a 30μg cefotaxime disk. Colonies typical of E. coli were selected preferentially from around the disk and identified by specific gadA/B E. coli gene PCR. Susceptibility testing and interpretation was performed using disc diffusion method according to CLSI guidelines. Full susceptible isolates were 51% and 49% had at least one acquired resistance. The resistance rate of E. coli for amoxicillin (Aml) was 43%, 30% trimethoprim/sulfamethoxazole (Sxt), 25% cefoxitin (Fox), 24%, amoxicillin/clavulanate (Amc), 18% cefotaxime (Ctx), 16% enrofloxacin (Enr), and 4% gentamicin (Cn). Multidrug-resistance (MDR) defined by resistance to 3 or more antimicrobial classes was present in 23 isolates (17%). Within MDR isolates, resistance to CI antimicrobial classes was present in 17 isolates to 3GC and 21 to enrofloxacin. The most frequent multiresistance profiles were AmlR-AmcR-EnrR-SxtRCtxR- FoxR (n=9) and Aml-Ctx-Enr-Sxt (n=3). Among E. coli strains, 3,7% (n=5) were extended-spectrum-β-lactamases (ESBL) producers, harbouring the blaCTX-M gene. In this study we showed a high frequency of resistance in veterinary E. coli strains from healthy dogs. Our results demonstrated that multidrug-resistant E. coli and ESBL producing strains are increasing and may compromise effective therapeutic options. Furthermore, resistance to CI antimicrobial classes is relevant. It is of prime importance that the utility of such antibacterial agents should be preserved, as resistance would have an important impact on human health due to the close and direct contact between pets and owners.
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Rodriguez, Dominguez Juan Carlos. "Nouvelles synthèses de dérivés hetérocycliques pour applications biologiques : (Céphalosporines, Coumarines et Indoles) = New synthesis of heterocyclic derivatives for biological applications (Cephalosporins, Coumarins and Indoles)." Metz, 2006. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2006/Rodriguez_Dominguez_Juan_Carlos_SMZ0618.pdf.
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Les céphalosporines de synthèse, les dérivés de coumarines et indoles sont des composés très intéressant dans le domaine de la biochimie. Les premières sont utilisées habituellement dans le système de santé mondiale contre les infections bactériennes ; les secondes et les dernières, sont présentes dans les sciences de la nature et de la vie avec des larges gammes d'activités et des usages biologiques. Due à leurs importantes applications, il apparait nécessaire d'avoir des méthodes efficaces pour synthétiser ces produits. Des temps de réactions plus courts, de bons rendements, un travail fait dans des conditions respectueuses de l'environnement, sont les aspects principaux pour diminuer les coûts des produits finaux. Dans ce travail nous développons des procédures synthétiques améliorées afin d'obtenir des antibiotiques céphalosporiniques de troisième génération, des coumarines et des acétates de 1-acétyle-indole-3-yl. La plupart de ces procédures réduisant les étapes de synthèse, le temps de réaction avec une augmentation sensible des rendements; les autres, introduisant quelques catalyseurs hétérogènes amenant les produit: finaux avec de bons rendements, similaires à ceux-là de la littérature sans avoir à traiter de résidus toxiquesSemisynthetic cephalosporins, coumarins and indoles derivatives are very valuable compounds in the biochemical branch. The firsts commonly used in the world health system against bacterial infections; the second and last ones, presents in nature and life sciences with wide spectra of biological activities and uses. Due their important applications it is necessary to count with appropiated methods of synthesis in order to obtain them. Shorter reactions time with good yields and as always as possible, in a friendly environment work up, are the main aspects to shoot down the costs of the final products. In this work we develop some improved synthetic procedures in order to obtain some cephalosporani-antibiotics of third generation, coumarins and (1-acetyl-indol-3-yl) acetates, the most part of them reducin! steps and time with a sensitive increase in yields; others, introducing some heterogeneus catalysts bringin ! the final products up with similar yields to those from literature with not toxic waste to treat
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Rodriguez, Dominguez Juan Carlos Kirsch Gilbert Prieto Sylvia. "Nouvelles synthèses de dérivés hetérocycliques pour applications biologiques (Céphalosporines, Coumarines et Indoles) = New synthesis of heterocyclic derivatives for biological applications (Cephalosporins, Coumarins and Indoles) /." [S.l.] : [s.n.], 2006. ftp://ftp.scd.univ-metz.fr/pub/Theses/2006/Rodriguez%20Dominguez.Juan%20Carlos.SMZ0618.pdf.
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Thomas, Claudia. "The epidemiology and control of Clostridium difficile infection in a Western Australian hospital." University of Western Australia. School of Population Health, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0011.
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[Truncated abstract] The prinicipal aim of this thesis was to explore the relationship between 3rd generation cephalosporin antibiotics and hospital-acquired Clostridium difficile-associated diarrhoea (CDAD). This antibiotic class has been implicated in the aetiology of CDAD; therefore restriction of these antibiotics via antibiotic policies represents a potential strategy for prevention and control of CDAD. Successful control of CDAD in hospitals translates to improved quality of care for patients, and a reduction of pressure on hospital resources. Therefore, the objectives of this study were to determine whether 3rd generation cephalosporins were related to CDAD, to evaluate the effect of changes to antibiotic policy on the incidence of CDAD, and to determine the impact of CDAD on patient length of stay and hospital costs. The study was conducted in Sir Charles Gairdner Hospital (SCGH), a public teaching hospital located in Perth, the capital city of the state of Western Australia. Evidence for an association between 3rd generation cephalosporins and CDAD was obtained from studies of ecologic- and individual-level data. A time series analysis of the relationship between monthly consumption of 3rd generation cephalosporins and the incidence of CDAD in SCGH was undertaken covering the period 1994 to 2000. The results demonstrated a positive relationship between the use of 3rd generation cephalosporins and CDAD. A matched case-control study that involved 193 adult inpatients diagnosed with CDAD and 386 adult inpatients without CDAD, selected from the period 1996 to 2000, was conducted. Information was collected on exposure to 3rd generation cephalosporin antibiotics during hospitalisation, as well as exposure to other antibiotics and medications, procedures, and comorbidities. Results from conditional logistic regression analyses found CDAD cases were six times more likely to be exposed to 3rd generation cephalosporins during their admission, prior to the onset of diarrhoea, than controls (adjusted odds ratio [OR] = 6.17, 95% confidence interval [CI] = 1.56-24.37). Approximately one third of CDAD in the study population could be attributed to 3rd generation cephalosporins. CDAD cases were also four times more likely to have been exposed to either amoxicillin-clavulanate or ticarcillin-clavulanate (adjusted OR=4.23, 95% CI=1.81-9.93). In October 1998, an antibiotic policy was introduced at SCGH that restricted the use of ceftriaxone, the 3rd generation cephalosporin most commonly used by the hospital. During 1999 and 2000, the incidence of CDAD halved as ceftriaxone consumption fell in response to this policy. The effect of this policy was demonstrated in the time series model; during the post-policy period the relationship between ceftriaxone and CDAD that was evident prior to the policy was cancelled out. From the individual-level data, obtained from the case-control study, a reduction in the prevalence of exposure to 3rd generation cephalosporins from 11% to 1% accounted for a 30% reduction in the incidence of CDAD. Data from the case-control study was also used to analyse the independent contribution of CDAD to length of stay and admission costs using multiple linear regression
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Correia, Joana Alves Veloso Domingues. "Colonização nosocomial por bactérias de Gram negativo resistentes produtoras de β-lactamases em cães." Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2015. http://hdl.handle.net/10400.5/8492.
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Dissertação de Mestrado Integrado em Medicina VeterináriaOs antibióticos β-lactâmicos são os mais usados, tanto na medicina veterinária como humana. O mecanismo de resistência mais comum a esta classe de antibióticos é a produção de β-lactamases (β-lactamases de espectro alargado - ESBLs, cefalosporinases - AmpCs e carbapenemases) por bactérias de Gram negativo. Os objectivos deste trabalho foram: detectar a presença e quantificar a colonização nosocomial do trato gastrointestinal por bactérias de Gram negativo produtoras de β-lactamases, em cães submetidos a tratamento cirúrgico e identificar quais os factores de risco responsáveis pela colonização e pelo aumento da carga bacteriana. Recolheram-se amostras fecais a 43 cães pertencentes ao grupo de controlo do ambiente (C1ca, n=43) e a 25 cães do grupo de cirurgia: na admissão ao hospital no dia da cirurgia (C1cx, n=25) e após a cirurgia (C2cx, n=22). As recolhas foram realizadas no Hospital Escolar da FMV-ULisboa, entre Fevereiro e Julho de 2014. As amostras foram processadas no Laboratório de Resistência aos Antibióticos e Biocidas (LRAB). Foram isoladas bactérias resistentes às cefalosporinas de 3ª geração (3CG) a partir do meio de MacConkey com 2μg/ml de cefotaxima e bactérias resistentes aos carbapenemos a partir do meio de MacConkey com 2μg/ml de meropenem. Foram realizados testes fenotípicos (Testes de Susceptibilidade aos Antibacterianos [TSA] pelo método de difusão em disco) e testes genotípicos (Polymerase Chain Reactions [PCRs]), de forma a identificar qual o mecanismo de resistência presente nas bactérias isoladas. Nas estirpes resistentes às 3CG, verificou-se um aumento significativo de animais colonizados em C2cx (73%, n=16/22), relativamente a C1cx (P=0,007) e a C1ca (P=0,017). O número de animais colonizados foi também significativamente superior no grupo C1ca (P=0,030) relativamente aos cães em C1cx. As contagens foram significativamente superiores em C2cx comparativamente a C1cx(P=0,004) e a C1ca(P<0,0001), e em C1ca relativamente a C1cx (P=0,0006). Entre os possíveis factores de risco analisados o factor residente (P=0,030) foi o único significativo para o aumento do número de animais colonizados com estirpes resistentes às 3CG e o factor tempo de contacto com a FMV(P=0,001) para o aumento da carga bacteriana. A resistência aos carbapenemos em C1cx foi de 4% (n=1), em C2cx de 23% (n=5) e no grupo C1ca foi de 2% (n=1). As β-lactamases mais prevalentes foram as ESBLs, foram detectadas apenas duas AmpCs plasmídicas e não foram detectadas Carbapenemases. Este trabalho vem reforçar a importância da aplicação de sistemas de controlo de colonização e de infecção nosocomial, para assim melhorar os cuidados de saúde animal e proteger a Saúde Pública.
ABSTRACT – NOSOCOMIAL COLONIZATION BY RESISTANT β-LACTAMASES PRODUCERS GRAM NEGATIVE BACTERIA IN DOGS - β-Lactam antibiotics are the most frequently used both in human and veterinary medicine. The most common resistant mechanism to this class of antibiotics is the production of β- lactamases (Extended Spectrum β-lactamases - ESBLs, Cephalosporinases - AmpCs and Carbapenemases) by Gram negative bacteria. The aim of this study was to detect the presence and quantify nosocomial colonization of the gastrointestinal tract by β-lactamase producing Gram negative bacteria on dogs treated surgically and identify the risks factors responsible for the colonization and the increased bacterial quantification. Fecal samples were collected from 43 dogs belonging to the environmental control group (C1ca, n=43) and 25 dogs from the surgery group: on admission to the hospital before surgery (C1cx, n=25) and after surgery (C2cx, n=22). The samples were collected at the FMV-ULisboa Veterinary Teaching Hospital between January and July 2014. The samples were treated in the FMV-ULisboa Laboratory of Resistance to Antibiotics and Biocids. Bacteria resistant to 3rd generation cephalosporins (3CG) were isolated from MacConkey medium with 2μg/μl cefotaxime and carbapenem resistant bacteria were isolated from MacConkey medium with 2μg/μl of meropenem. Phenotypic tests (Antibacterial Susceptibility Testing using the disk diffusion method) and genotypic tests (Polymerase Chain Reactions) were used in order to identify the resistant mechanism in isolated bacteria. There was a significant increase of 3CG resistant strains colonized dogs in C2cx (73%, n=16/22) comparing to C1cx (P=0,007) and C1ca (P=0,017). The number of colonized dogs was also significantly higher in C1ca group (P=0,030) comparing to the C1cx. The bacteria number were significantly higher in C2cx comparing to C1cx(P=0,004) and C1ca group (P<0,0001), and in C1ca group comparing to C1cx (P=0,0006). The resident risk factor was the only one significant (P=0,030) for the increase of colonized animals with 3CG resistant strains and FMV contact time (since when dogs come to FMV) risk factor was the only one significant (P=0,001) for the increased bacterial quantification. The carbapenem resistance bacteria colonization in the dogs of C1cx was 4% (n=1) and in C2cx was 23% (n=5) and in C1ca group was 2% (n=1). The most prevalent β-lactamases were the ESBLs, only two plasmid mediated AmpC were detected and none Carbapenemases. This study enhances the importance of nosocomial colonization and infection control systems, in order to improve animal health and safeguard Public Health.
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Lipscomb, Sarah. "Studies on cephalosporin biosynthesis." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433559.
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Lee, Hwei-Jen. "Studies on cephalosporin biosynthesis." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409949.
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Elton, Rebecca Charlotte. "Evaluation of a proximal tubule incubation system for the detection of nephrotoxicants." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243494.
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Weisenberger, Klaus. "Downstream processing of cephalosporin c." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330236.
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Morgan, Nicholas. "Genetic engineering of cephalosporin biosynthesis." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239322.
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Shorrock, Celia Patricia. "Studies on penicillin and cephalosporin biosynthesis." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298666.
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Norman, Elizabeth. "Biochemical genetics of Cephalosporin C production." Thesis, University of Nottingham, 1988. http://eprints.nottingham.ac.uk/14317/.
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The biosynthetic pathway which leads, in Cephalosporium acremonium, to the production of the commercially important β-lactam antibiotic Cephalosporin C (CPC) has been the subject of extensive biochemical studies and is now well characterized. In contrast, genetic analysis in this organism was limited until the application of protoplast fusion techniques facilitated parasexual analysis and allowed a genetic map to be established. (Hamlyn 1982; Hamlyn et al 1985). Subsequently, work leading to our understanding of the genetic basis of the CPC biosynthetic pathway in C. acremonium began. (Perez-Martinez 1984; Perez-Martinez and Peberdy in preparation). The studies described here were aimed at extending this understanding to a point at which individual genes implicated in the pathway could be identified and positioned on the linkage map. A programme of mutagenesis resulted in the production of a number of 'blocked' mutant strains of C. acremonium which were phenotypically particular steps of the CPC biosynthetic pathway. The segregation of several of these mutations relative to other genetic markers was examined. Crosses designed to detect complementation between mutations resulting in a 'blocked' phenotype were carried out and involved strains produced in other laboratories in addition to those characterized during this work. Complementation was shown between two mutations which apparently affected the same step in CPL biosynthesis (the conversion of penicillin N into deacetoxycephalosporin C) and evidence for the linkage of one of the mutations (cnp-6) to a mutation resulting in a requirement for inositol was obtained. During the course of the complementation studies, it was noted that the haploid and heterozygous products obtained following C. acremonium protoplast fusion crosses did not always behave in the typical manner described previously. (Hamlyn 1984). The persistent heterogeneity of these fusion products and the possible implications of this are discussed.
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Meier, Bianca. "Entwicklung und Anwendung enzymimmunologischer Verfahren zum Nachweis von Cefalexin, Ceftiofur und Desfuroylceftiofur in Milch." Giessen : VVB Laufersweiler, 2008. http://d-nb.info/988308673/04.
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Layland, Nicola Joanne. "Some reactions of penicillin and cephalosporin derivatives." Thesis, University of Huddersfield, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358674.
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McHattie, Derek. "The synthesis and cephalosporin coupling of azaindolizines." Thesis, Robert Gordon University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329122.
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Nascimento, Tatiane. "Ocorrência e diversidade de bactérias gram-negativas multirresistentes em ambientes aquáticos públicos no estado de São Paulo." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-26082015-175023/.
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Atividades antropogênicas relacionadas ao uso massivo de antibacterianos tem favorecido para que ambientes aquáticos sejam importantes locais para seleção e/ou disseminação de bactérias multirresistentes (MR). O objetivo do estudo foi monitorar a ocorrência de bactérias MRs em ambientes aquáticos públicos no estado de SP, caracterizando genótipos de resistência adquirida. Foram analisados 50 isolados de bactérias gram-negativas, recuperadas de amostras de água, sendo que 70% dos isolados apresentaram perfil de MR, identificando-se os genes blaCTX-M-2 (n= 5), blaCTX-M-9 (n= 1), blaCTX-M-15 (n= 2), blaKPC-2 (n= 3), qnrB (n= 1), oqxA (n= 3), oqxB (n= 3) e, aac(6)1b-cr (n= 7). Destaca-se a primeira detecção de A. calcoaceticus produtora de KPC-2. Ambientes aquáticos de acesso público podem ser importantes fontes para a disseminação e/ou transmissão de uma ampla variedade de espécies bacterianas MRs tanto para seres humanos como para ecossistemas associados, sendo que a presença de genótipos endêmicos sugere contaminação por esgoto doméstico e/ou hospitalar.Anthropogenic activities related to the massive use of antibacterial has contributed to the selection and spread of multidrug-resistant (MDR) into the aquatic environment. This study aimed to monitor the occurrence of MDR bacteria in public aquatic environments, in the state of São Paulo, characterizing genotypes of acquired resistance. Of the 50 gram-negative isolates, recovered of water samples, 70% exhibited a MDR profile. Indeed, blaCTX-M-2 (n= 5), blaCTX-M-9 (n= 1), blaCTX-M-15 (n= 2)-, blaKPC-2 (n= 3)-, qnrB (n= 1)-, oqxA (n= 3)-, oqxB (n= 3)- and aac(6)-1b-cr (n = 7) genes were identified. Noteworthy is the first the detection of KPC-2-producing Acinetobacter calcoaceticus. Aquatic environments, with public access, may be important sources for the dissemination and/or transmission of a wide variety of MDR bacterial species to both humans and associated ecosystems. Moreover, the presence of endemic genotypes suggests contamination by domestic and/or hospital sewage.
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Alhadiyah, Badreddin M. Hashim. "Analytical and protein-binding studies of cephalosporin antibiotics." Thesis, University of Bath, 1989. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760595.
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Melo, Luana Claudino de. "Microbiota comensal de animais de companhia como reservatório de genes codificadores de b-lactamases de espectro estendido (ESBLs) e resistência a quinolonas mediada por plasmídeos (PMQR)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-28112014-104202/.
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O presente estudo visou determinar a prevalência de bactérias Gram-negativas produtoras de produzem b-lactamases de amplo espectro (ESBL) e resistência adquirida a quinolonas mediada por plasmídeos (PMQR) em animais de estimação, investigando o potencial papel destes hospedeiros como portadores assintomáticos. Em 2012, foram coletadas 216 amostras (fezes e saliva) de 108 animais de companhia (29 gatos e 79 cães) abrigados em casas de família, um centro de acolhimento de animais abandonados, e no Centro de Controle de Zoonoses da Cidade de São Paulo. Do total de cepas estudadas, 85% apresentaram fenótipo sugestivo de PMQR; enquanto que 62% dos isolados exibiram um fenótipo característico e sugestivo para produção de ESBL, sendo na sua maioria identificadas como E. coli. Dentre os isolados, 14 carregaram variantes do gene blaCTX-M, 9 foram positivos para o gene blaTEM, e 6 foram positivos para blaSHV. Em relação às cepas resistentes às Q/FQ, 56% (n= 43) foram positivas para a presença do gene qnr, o qual foi identificado em 11 espécies diferentes. Os resultados apresentados demostram que animais de companhia podem ser portadores assintomáticos de cepas produtoras de ESBL e PMQR.The present study aimed to determine the prevalence of Gram-negative bacteria producing b-lactamases producing broad-spectrum (ESBL) and acquired resistance to quinolones mediated by plasmids (PMQR) in pets, investigating the potential role of these hosts as asymptomatic carriers. In 2012, 216 samples (feces and saliva) of 108 companion animals (29 cats and 79 dogs) housed in shelters or a Zoonosis Control Center were collected from São Paulo city. Of the total strains studied, 85% had a phenotype suggestive for PMQR; while 62 % of the isolates exhibited a characteristic phenotype and suggestive for ESBL-producing genes, with the most identified as E. coli. Among the isolates, 14 carried variants blaCTX -M gene 9 were positive for blaTEM gene, and 6 were positive for blaSHV. Regarding resistant Q/FQ isolates, 56% (n = 43) were positive for the presence of qnr gene, which was identified on 11 different species. The results presented demonstrate that pets can be asymptomatic carriers of ESBL producing strains and PMQR.
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Martyres, Dominic H. "Bicyclic penicillin mimics." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365770.
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Jenni, Wolfgang. "Neue Antibiotika gegen grampositive Bakterien und oral wirksame Cephalosporine." Diss., lmu, 2001. http://nbn-resolving.de/urn:nbn:de:bvb:19-23646.
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Hunter, Alan Christy. "The biotransformation of steroids by Cephalosporium aphidicola." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360523.
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Peloso, Pedro Fernandez Del. "Análise da prevalência de resistência aos antimicrobianos em pacientes com infecção urinária comunitária de um laboratório privado na cidade do Rio de Janeiro." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=7208.
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Descrever a prevalência das espécies bacterianas isoladas nas infecções urinárias comunitárias. Descrever os perfis de susceptibilidade aos antibióticos de uso oral utilizado frente às bactérias isoladas nas infecções urinárias comunitárias. Avaliar a prevalência de fenótipos de resistência bacterianos através dos resultados dos testes de susceptibilidade e dos rastreamentos específicos utilizados. Amostras colhidas exclusivamente no atendimento ambulatorial com contagens de unidades formadoras de colônias entre 100.000 a ≥1.000.000 por mililitro (UCF/ml) Com ou sem piúria no exame de elementos anormais na urina e sedimentoscopia (EAS). Foram analisados retrospectivamente os resultados de urinoculturas e dos testes de susceptibilidade a antimicrobianos, realizados em um Laboratório da rede privada na cidade do Rio de janeiro, de pacientes atendidos em ambulatórios e com quadros de ITU. As amostras de urina coletadas englobavam basicamente os seguintes bairros: Botafogo, Barra da Tijuca, Ipanema, Copacabana, Tijuca e Centro. Foram analisados um total de 8.475 culturas de urina divididas em 7.286 urinas de pacientes femininos e 1.189 de pacientes masculinos entre Janeiro de 2006 a Dezembro de 2012. As amostras foram todas coletadas na Cidade do Rio de Janeiro e englobavam basicamente os seguintes bairros: Botafogo, Barra da Tijuca, Ipanema, Copacabana, Tijuca e Centro. Encontramos um percentual de resistência de 27% para ciprofloxacina frente à Escherichia coli que com 68.23% é a principal etiologia encontrada na ITU na comunidade os resultados das três fluoroquinolonas avaliadas no estudo, ciprofloxacina (2 geração), levofloxacina (3 geração) e norfloxacina (2 geração), acharemos respectivamente 27%, 25% e 20% de resistência em Escherichia coli. O uso de fluoroquinolonas em infecções urinárias comunitárias e consequentemente os achados de padrões de resistência neste estudo, reforçam o que já foi descrito em outros trabalhos. A cefalosporina de 2 geração (cefuroxima), demonstrou percentuais de resistência bastante satisfatórios frente as principais etiologias. Em Escherichia coli o percentual foi de 2%, em Klebsiella pneumoniae 3% e em Proteus mirabilis não houve nenhum achado de resistência. Uma das vantagens da cefuroxima é ser ativa quanto à produção de beta lactamase, conferindo um espectro maior frente a possíveis produtoras desta enzima. Seu esquema posológico é de 250mg duas vezes ao dia por 7 dias para infecções urinárias não complicadas. O meio mais eficaz de melhorar a administração antimicrobiana provavelmente envolverá um programa abrangente que incorpora múltiplas estratégias e colaboração entre as diversas especialidades dentro de uma determinada instituição de saúde. Neste contexto, a observação periódica da incidência bacteriana com seus respectivos índices de resistência aos antimicrobianos por sitio de infecção e correlação com os antibióticos mais comumente utilizados, é mandatória para o sucesso terapêutico.Describe the prevalence of bacterial species isolated from community acquired urinary tract infections and to describe the bacterial susceptibility profiles to oral antimicrobials. The prevalence of resistant phenotypes was also evaluated. Samples were taken from outpatients whose urine cultures showed >= 100,000 Colony Forming Units per milliliter (CFU/ml) with or without pyuria on direct examination of urine sediment samples. Urine culture results were retrospectively reviewed and antimicrobial susceptibility testing performed in a private clinical laboratory located in Rio de Janeiro. A total of 8475 urine cultures performed between January 2006 and December 2012 were analyzed. Female urine samples represented 7286 samples while male samples represented 1189 samples. Escherichia coli was found as the main etiology among urinary tract infections, (68,23%) showing 27% of ciprofloxaxin resistance, 25% Levofloxacin resistance and 20% Norfloxacin resistance. The use of fluoroquinolones in community acquired urinary tract infections and the resistance patterns found in this present study reinforces what has been described by other authors. A second generation cephalosporin (cefuroxime) showed resistance in main etiologies - E. coli 2% and K. pneumoniae 3%, while Proteus mirabilis showed no resistance at all. Among the main advantages of cefuroxime is the activity against the production of beta lactamases. The regimen dosage is 250mg twice a day for 7 days to treat uncomplicated urinary tract infections. The most effective way to improve antimicrobials administration is to develop a comprehensive program that incorporates multiple strategies and collaborative work between different medical specialties inside a healthcare institution. In such a context, the bacterial incidence rates and antimicrobial resistance rates should be closely observed and correlated to infection sites for better achievement of success in antimicrobial therapy.
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ARROYO, VINCENT. "Etude epidemiologique des enterobacter aerogenes resistants aux cephalosporines par ribotypage." Lyon 1, 1994. http://www.theses.fr/1994LYO1M146.
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Becker, Matthias. "LC-MS/MS-Methoden zur Rückstandsanalyse von Penicillinen, Cephalosporinen und Aminoglycosid-Antibiotika." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974085324.
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