Abstrait

Beta-lactamases in P. aeruginosa: A Threat to Clinical Therapeutics

Supriya Tankhiwale

Pseudomonas aeruginosa is the third most common pathogen responsible for nosocomial infections. The prevalence of multiple drug resistant Pseudomonas aeruginosa isolates harboring beta lactamases have been increasing. The present study is designed to determine the occurrence of various beta lactamases in Pseudomonas aeruginosa. A total of 237 clinical isolates of P. aeruginosa were tested for the presence of AmpC beta-lactamase, Extended Spectrum Beta-Lactamase (ESBL) and Metallo Beta-Lactamase (MBL) enzyme. Detection of ESBL was done by the combined disk diffusion method as per Clinical and Laboratory Standards Institute (CLSI) guidelines whereas MBL were detected by the Imipenem EDTA disk potentiation test and AmpC beta-lactamase was detected by disk antagonism test and modified three-dimensional method respectively. A total of 82 (34.60%) isolates were positive for AmpC beta-lactamase, 52 (21.94%) ESBL and 40 (16.87%) were positive for MBL. Coproduction of AmpC with extended spectrum beta-lactamase and metallo beta-lactamase was reported in 20 (08.44%) and 24 (10.12%) isolates, respectively. All the three beta lactamases co-production was found to be in 7 (2.95%) isolates. The study emphasizes early detection of these multidrug resistant P. aeruginosa producing beta-lactamase enzymes of diverse mechanisms. Thus proper antibiotic policy and measures to restrict the indiscriminate use of antibiotics should be taken to minimize the emergence of these multiple beta-lactamase producing pathogens to avoid therapeutic failures and nosocomial outbreaks.