A study on Metallo-β lactamase producing Imepenem nonsusceptible multi-drug resistant Pseudomonas aeruginosa in different clinical specimens in a tertiary care hospital in Kolkata.

Metallo-β-lactamase producing carbapenem non-susceptible multidrug resistant Pseudomonas aeruginosa creates a great challenge for treatment as the choice of antibiotics gets severely restricted .This study aimed at detecting such strains in different clinical samples in a tertiary care hospital in Kolkata. Materials and methods-Out of 169 isolates detected as Pseudomonas spp.in Microbiology laboratory 98 consecutive non-duplicate isolates phenotypically confirmed as Pseudomonas aeruginosa were selected following inclusion criteria of being resistant to≥ 3 different classes of antibiotics including Imepenem. Antibiogram with antibiotics suggested by CLSI-2011 was performed and resistance to different antibiotics was recorded .Then combined disc test with Imepenem(10µg) and Imepenem(10µg)+EDTA (750 µg)was performed.Observation - Strains showing zone difference ≥ 7mm during combined disc test were considered as metallo-β lactamase producing multidrug resistant strains and those showing<7mm increase in zone size or no increase in zone size or total zone size less than 13 mm with Imepenem+EDTA were considered as MBL non- producers.51 isolates out of 98(52.04% ) multidrug resistant oneswere diagnosed as MBL producing multi- drug resistant isolates .Sample wise distribution showed highest rate of infection with imepenem non-susceptible multidrug resistant Pseudomonas aeruginosa was seen in fluid samples(66.66%) and lowest rate (14.28%) in blood sample isolates.Conclusion-The finding of 52.04% MBLproducing isolates out of 98 multidrug resistant Pseudomonas aeruginosa is an alarming condition in the background of tertiary care hospital and may be the