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Caracterização de Pseudomonas aeruginosa encontradas colonizando e/ou infectando pacientes queimados internados em um hospital público da cidade do Rio de Janeiro
| Content Provider | Semantic Scholar |
|---|---|
| Author | Silva, Keila De Cássia Ferreira De Almeida |
| Copyright Year | 2017 |
| Abstract | Pseudomonas aeruginosa is major causative pathogens of serious infections in burn patients and is associated with high mortality and morbidity rates. The high plasticity of its genome confers to this organism the ability to become multiresistant to antibiotics, difficulting the threathment due to reduced therapeutic options. This study aimed to analyze 35 strains of P. aeruginosa isolated from burn patients and the tank where balneotherapy was held in a burn treatment center (BTC), determining the resistance profile to antimicrobial agents, genetic factors related to virulence and antimicrobial resistance, the ability to produce biofilms and biocide action thereon and perform molecular typing of the strains involved. Antimicrobial susceptibility was assessed using the disk diffusion method, according to the criteria of the Clinical and Laboratory Standards Institute (CLSI). The research for resistance genes encoding β-lactamases (blaPER-1, blaCTX-M, blaOXA-10, blaGES-1, blaVIM, blaIMP, blaSPM-1, blaKPC, blaNDM and blaSIM) and the virulence genes exoS and exoU was performed using the Polymerase Chain Reaction (PCR). The phenotypic test Carba NP, was used in order to detect enzymatic hydrolytic activity to carbapenems. Biofilm formation ability was evaluated through plate for microtitration and stainless steel coupon, the latter being used to verify the efficacy of three biocides (sodium hypochlorite 1%, hydrogen peroxide 5% and chlorhexidine 4%) to remove formed biofilms. The strains were typed by Multilocus Sequence Typing technique (MLST). According to the antimicrobial susceptibility test, a high resistance pattern was observed in which 71.5% (25/35) of strains were multidrug resistant (MDR). The highest percentage of resistance was to ciprofloxacin (94.3%; 33/35), followed by gentamicin (88.6%; 31/35). It was also observed resistance to β-lactams antibiotics, including the carbapenems (22.9%; 8/35). Regarding the resistance genes investigated were found the blaGES-1 in 34,3% (12/35) of the strains and the blaCTX-M in a single strain. None of the searched genes encoding carbapenemases was found. Similarly, no enzymatic hydrolytic activity to imipenem was detected by Carba NP test, suggesting that other resistance mechanisms may be involved, such as pump over expression and loss of outer membrane porin (OprD). The exoS virulence gen was the most prevalent being present in 71.4% (25/35) of the strains, while exoU was detected in 14.3% (5/35), however all strains that harbored this gene were carbapenems resistant. Eleven (31.4%) of 35 isolates were biofilm formers using the plate for microtitration, which mostly (81.8%) belonging to clone A (obtained in a previous study by PFGE) that was the most prevalent infecting/ colonizing patients and contaminating balneotherapy tank. Removal of biofilm formed in stainless steel coupon surface was effective for all three biocides tested (sodium hypochlorite 1%, hydrogen peroxide 5% and chlorhexidine 4%), with no viable cell count after contact with biocides solutions. The MLST originated two new sequencing types, ST2236 and ST2237. It is concluded from this study that the reduction of therapeutic options associated with the presence of virulence genes, can aggravate the situation of these patients. As well as the presence of genes as blaGES-1 and blaCTX-M is worrying as they may be spread among the other strains by horizontal transmission, if there is no adequate control. However, the removal test of biofilms showed that, if the disinfection is carried out in a correct way, cross-contamination between patients can be avoided. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://app.uff.br/riuff/bitstream/1/3038/1/Silva,%20Keila%20de%20C%C3%A1ssia%20Ferreira%20de%20Almeida%20%5BDisserta%C3%A7%C3%A3o,%202016%5D.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
