Metallo-Beta-Lactamase Producing Gram-Negative Bacteria among Patients Visiting Shahid Gangalal National Heart Centre

Background: The rapid spread of acquired Metallo-Beta-Lactamases (MBL) among major Gram-negative pathogens is an emerging threat and a matter of concern worldwide as it results into fewer therapeutic options for the treatment. Therefore, this study was undertaken to determine the prevalence of MBL producing Gram-negative bacteria isolated from different clinical samples. Methods: A total of 490 samples were analyzed, at the Microbiology Department of Shahid Gangalal National Heart Centre (SGNHC), Bansbari, Kathmandu from December 2013 to June 2014, for routine culture and antibiotic susceptibility testing. MBL detection was done by Imipenem-EDTA Combined Disc Test. Results: Out of 490 samples analyzed, 107 showed positive growth. Fortytwo percent of the Gram-negative isolates were Multi Drug Resistant (MDR). Among 107 Gram-negative isolates, 66 ceftazidime resistant isolates were screened for MBL production of which 9 (13.6%) were found to be MBL positive. All MBL positive isolates were Pseudomonasaeruginosa. None other Gramnegative bacteria were found to produce MBL. Prevalence of MBL producing P. aeruginosa was 20% and all the isolates were MDR. All the MBL producing P. aeruginosa were isolated from hospitalized patients. Conclusions: This study showed MBL production in a considerable number of P. aeruginosa isolates with MDR phenotypes. There is a need to track the detection of MBL producers and judicious use of carbapenems is necessary to prevent the further spread of these organisms.