Abstract

CONTEXT: Carbapenems, including imipenem (IPM) and meropenem (MRP), are the most potent antibacterial agents used for the treatment of infections initiated by multidrug-resistant gram-negative bacilli. Pseudomonas aeruginosa, is a commonly encountered nosocomial pathogen, especially in immunocompromised patients, thus, inflicting significant morbidity and mortality, worldwide. The emergence of MBL‑producing Pseudomonas aeruginosa is a challenge to microbiology laboratories because there are no standardized guidelines available to detect them. This study aimed to compare four phenotypic methods to detect MBL production in Pseudomonas aeruginosa and to determine the antibiotic sensitivity of MBL‑producing isolates.
 
MATERIALS AND METHODS: A total of 200 clinical isolates of Pseudomonas aeruginosa were tested for MBL production. Meropenem (MRP) resistant Pseudomonas aeruginosa were taken as MBL screening. MBL detection was done by three phenotypic methods 1) Combined disk synergy test (CDST). 2) Double disk synergy test (DDST) and 3) E-test.
 
RESULTS: out of 200 Pseudomonas aeruginosa, 73 were resistant to Meropenem as screening positive. Out of 73, 34(46.5%) isolates were MBL positive by CDST methods, 33(45%) by DDST method and 33(45%) by E-test. Colistin and polymyxin B were found to be 100% sensitive.
 
CONCLUSION: The study result demonstrates the antibiotic sensitivity pattern of MBL-positive isolates suggests that early detection of MBL-producingP. aeruginosa and determination of their antibiotic sensitivity are of crucial importance to start appropriate treatment. It was observed in this present study that the MBL E-test followed by DDST were effective options for MBL detection in this part of the country.