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| Author(s): |
Renata Galetti
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Ciências Farmacêuticas de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2014-11-06 |
| Examining board members: |
Ana Lucia da Costa Darini;
Valdes Roberto Bollela;
Eliana Guedes Stehling;
Alessandro de Mello Varani
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| Advisor: | Ana Lucia da Costa Darini |
| Abstract | |
The presence of conjugative plasmids as IncP, IncU and Inc FII carrying resistance genes in Pseudomonas aeruginosa is very important because t these plasmids can be shared among different bacteria, spreading antibiotic resistance. Knowledge of these genes as well as genetic elements carrying these genes it is important to understend the factors that contribute to the spread of resistance, helping to control the spread of antibiotic resistance. Today there is no plasmid typing scheme to P. aeruginosa and few papers are found about this subject. The purpose of this study was to investigate resistance genes, genetic environment of these genes and clonal relationship of the isolates carrying these resistance genes. In the period of this study was studied 293 P. aeruginosa resistant to third and fourth generations of cephalosporins and/or carbapenens isolated of patients from hosptital from Ribeirão Preto, Belo Horizonte-MG, Franca-SP, Cuiabá-MT, Barretos-SP and Rio Branco-AC. Resistance genes were investigated by PCR. Twelve isolates were identified carrying blaSPM-1 gene, 16 isolates carrying blaCTX-M-2 gene and 3 isolates carrying blaKPC-2 gene. Clonal profiles of isolates producing resistance genes were investigated by PFGE and MLST. Plasmid typing was performed by PFGE-S1 nuclease, specific hybridizations and PCR replicon typing (PBRT). Two isolates presented a 3kb plasmid non-typeable by PBRT carrying blaKPC-2 gene. In all isolates SPM-1-producers were identified two copies of insertion sequence ISCR4, a copy upstream and a copy downstream to blaSPM-1 gene inserted in chromosomal DNA. In 13 of 16 isolates CTX-M-2-producers the blaCTX-M-2 gene was found associated to insertion sequence ISCR1 and in 3 isolates was associated to insertion sequence ISEcp1 also inserted in chromosomal DNA. Genetic environment of blaKPC-2 gene in the isolates studied it is different from those found in the literature. Isolates producing bla genes are clonally diversified using both PFGE and MLST showing that various clones are responsible to spread these resistance genes. This work identified and characterized 31 P. aeruginosa-?-lactamase-producing, the genetic environment of these genes and the clonal relationship of isolates collected from different periods from different cities of Brazil. These data can help us to understand the factors that are involved in the spread of antibiotics resistance and to help the Hospital Infection Control Committee to define strategies to control the spread of these microorganisms preventing outbreaks of resistant. (AU) | |