European Journal of Biomedical and Pharmaceutical Sciences

MOLECULAR CHARACTERIZATION OF METALLO BETA LACTAMASE PRODUCING CLINICAL ISOLATES OF PSEUDOMONAS AERUGINOSA

Shyamasree Nandy *, Ashish K. Asthana, Molly Madan

ABSTRACT

Present study was carried out in the Microbiology Dept of Subharthi Medical College, Meerut, UP. 56 non duplicate isolates of Pseudomonas aeruginosa resistant to either or both Imipenem and Meropenem were collected. Material and Methods: Four phenotypic methods were employed for screening of MBL namely Double disc synergy test (DDST) with Imipenem and 750μgEDTA, Combined Disc test with Imipenem EDTA & Meropenem EDTA, E Test with Imipenem EDTA.PCR was done for molecular characterization of the MBL producers. Results: Among 56 isolates 13 isolates were found to be MBL producer.09 of the isolates were carrying blaVIM and 04 were carrying blaIMP gene. No other gene were found. Maximum number of isolates were obtained in the age group 21 to 30 years. No MBL producer was found in Meropenem sensitive isolates.For screening of metallobetalactamase Meropenem was found to be a better marker than Imipenem.DDST with Imipenem and Meropenem was found to have same specificity and sensitivity. Etest failed to detect MBL in Imipenem sensitive isolates. All the MBL positive isolates showed resistance towards aminoglycosides. Colistin was 100% sensitive sitive and the next effective drug was Amikacin. In most of the MBL positive isolates Aztreonam was resistant.This can be attributed to the co presence of multiple mechanism of resistance in MBL positive isolates.

Keywords: MBL, Pseudomonas aeruginosa, bla VIM, bla IMP.