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| Author(s): |
Ketrin Cristina da Silva
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2016-03-21 |
| Examining board members: |
Andrea Micke Moreno;
Milena Dropa;
Marcos Bryan Heinemann;
Nilton Erbet Lincopan Huenuman;
Alessandra Figueiredo de Castro Nassar
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| Advisor: | Andrea Micke Moreno |
| Abstract | |
Extended-spectrum beta-lactamase production (ESBL) became a great challenge regarding public health because limit the therapeutic options to treat infections by gram-negative bacteria. The aim of this study were evaluate the occurrence of ESBL producers in Brazilian swine farms and characterize blaESBL-carrying plasmids by sizing and incompatibility group and presence of additional resistance genes. Strains were isolated in MacConkey agar and identified by Maldi-Tof. Next, the minimal inhibitory concentration values were determined by microdilution and/or agar dilution to aminoglycosides, carbapenems, cephalosporins, fluoroquinolones, tetracyclines, sulfas and cephalosporin/inhibitors association. Betalactamase encoding genes, plasmid incompatibility group and Escherichia coli phylogenetic group were determined by PCR. Clonal relatedness was evaluated by ERIC-PCR and MLST. Finally, the blaCTX-M-15 genetic environment was determined by PCR and/or sequencing and blaESBL-carrying plasmids transferred to E. coli TOP10 and C600 receptor strains by transformation and conjugation, respectively, and partially sequenced. CTX-M-2-producing E. coli were the most prevalent phenotype, which were endemic in Minas Gerais State. Moreover, the CTX-M-15 enzyme emerged among E. coli (ST224, ST410, ST1284), Klebsiella pneumoniae, Enterobacter cloacae e Pseudomonas aeruginosa (ST3201) strains. The blaCTX-M-15 was associated with IncF plasmids, which were successfully transferred to E.coli TOP10, similarly, IncF plasmids were found harboring the blaCTX-M-2. The blaCTX-M-8, detected in four novel E. coli sequence types (ST5845, ST5847, ST5848 e ST5350), was not acquired by receptor strains. Thus, the surveillance of resistant phenotypes in swine production must be established as a priority as well as narrow spectrum antimicrobials prescription antimicrobial instead broad spectrum to prevent the dissemination of these phenotypes in farms and their transmission to human population. (AU) | |
| FAPESP's process: | 12/08332-0 - Molecular characterization of plasmids harboring extended-spectrum Beta-lactamase-encoding genes in Enterobacteriaceas isolated from swine |
| Grantee: | Ketrin Cristina da Silva |
| Support Opportunities: | Scholarships in Brazil - Doctorate |