Detection of prevalence of metallo-beta lactamases in clinical isolates of imipenem resistant Pseudomonas aeruginosa from neonatal septicaemia cases in a tertiary hospital in Odisha, India
Background: Pseudomonas aeruginosa is a clinically troublesome gram-negative pathogen that causes both opportunistic infections and nosocomial outbreaks. Metallo beta lactamase have recently emerged as a worrisome resistance mechanism. Carbapenems had been the drug of choice for the infections caused by most penicillin- or cephalosporin-resistant gram-negative bacteria due to its broad-spectrum activity and stability to hydrolysis by most beta-lactamases. This does not hold good anymore due to rapid uprise of MBL producing strains. The current research covered 163 hospitalized cases of neonatal septicaemia from which Pseudomonas aeruginosa is isolated in the Paediatric Department of KIMS, Bhubaneswar. The study aimed at detecting the prevalence of metallo-beta lactamases in clinical isolates of imipenem resistant Pseudomonas aeruginosa from neonatal septicemia cases and to establish the antibiogram of Imipenem-resistant P. aeruginosa these cases. Methods: Clinical samples obtained from suspected cases of neonatal septicemia were first cultured by conventional methods and then identification was done by VITEK-2 instrument. Metallo beta lactamase (MBL) production was done by combined disc synergy test (CDST) using imipenem and EDTA (CDST-IPM) and double disc synergy test (DDST) using IPM and EDTA (DDST-IPM). Results: Among 1510 processed clinical specimens from cases of neonatal septicaemia; 637 (42.18%) showed positive growth of various clinically significant pathogens. Out of them in 163 (25.58%) cases Pseudomonas spp. was isolated. Of these, a total of 95 (58.28%) Pseudomonas spp. was found resistant to imipenem. All imipenem-resistant Pseudomonas isolates were positive for MBL by CDST imipenem-EDTA (CDST-IPM) method, whereas 89 (93.68%) were positive by DDST-IPM method, respectively. Pseudomonas aeruginosa was mostly isolated from endotracheal tube aspirate (57.89%) followed by pus (56.41%). Out of the 95 cases of MBL-producing Pseudomonas; 46 (48.42%) isolates showed the maximum susceptibility to piperacillin-tazobactam combination. All MBL-producing Pseudomonas isolates were resistant to ceftriaxone.Conclusions: MBL-producing Pseudomonas is found to be highly prevalent in our hospital, which is one of the major causes of multidrug resistance and need regular surveillance and strict adherence to a robust antibiotic policy.