ABSTRACT
Introduction:
Pseudomonas aeruginosa is a leading cause of opportunistic infections in humans, and the choice of effective antimicrobial agents to control this bacterium has been limited, mainly due to its ability to produce metallo-β-lactamases (MβL), enzymes capable of inactivating many antimicrobials through hydrolysis.
Objective:
This study aimed to detect the presence of multidrug-resistant (MDR) P. aeruginosa strains and the MβL-encoding genes (blaSPM, blaIMP and blaVIM) in nosocomial isolates in Maceió (AL).
Methods:
The isolates were collected from four public institutions/hospitals in Maceió, and cultures were identified by conventional methods. Antibiotic susceptibility was determined by the disk diffusion method according to the Clinical and Laboratory Standards Institute (CLSI), and polymerase chain reaction (PCR) was used to identify the presence of the MβL-encoding genes blaSPM, blaIMP and blaVIM.
RESULTS:
Forty-three strains of P. aeruginosa were MDR among 85 identified nosocomial isolates (50.6%), 79.1% and 20% of which were resistant to carbapenem (imipenem and meropenem) and aztreonam, respectively. PCR was performed in susceptible or resistant isolates and we identified nine (20.9%) MDR strains with blaSPM gene, whereas only one strain had blaIMP and none blaVIM positive was found.
Conclusion:
Production of MβL is an important mechanism of resistance to carbapenems and other β-lactams among P. aeruginosa strains in the evaluated samples. We reported the first identification of MβL-encoding genes in P. aeruginosa from nosocomial environments in Maceió, a new insight for the epidemiology of MβL in the Northeastern region of Brazil.
Key words:
Pseudomonas aeruginosa; carbapenems; β-lactamases
A) amplification of blaIMP gene (600 pb) in one strain; B) blaSPM gene (650 bp) in nine strains. Ladder 100 bp (M). PCR: polymerase chain reaction; IMP: imipenemase; SPM: São Paulo metallo-β-lactamase.