A prospective study on metallo-beta-lactamase producing pseudomonas aeruginosa in hospitalized patients in a tertiary care hospital in Kashmir, India.

Objectives: 1) To determine the prevalence of metallo-β-lactamase producing Pseudomonas aeruginosa in SKIMS; 2) To study the risk factors associated with MBL producing Pseudomonas aeruginosa; 3) To study sensitivity pattern of MBL producing Pseudomonas aeruginosa isolates. Study Design: Prospective hospital based study. Material & Methods: 283 isolates of Pseudomonas aeruginosa were obtained from various samples from patients in SKIMS over a period of one and a half year from 1 January 2007 to 30th June 2008. Antimicrobial susceptibility testing was done by Kirby-Bauer disk diffusion method. Pseudomonas aeruginosa isolates resistant to imipenem were then subjected to combined-disk test, MIC reduction and E-test for detection of metallo-β-lactamases. Results: Out of 283 Pseudomonas aeruginosa strains isolated during the study period, 38 (13.42%) were resistant to imipenem and 33 (11.66%) were found to be MBL producers by different methods. Highest number 8 (24.2%) of MBL positive isolates were from ICU and the predominant source was urine. Prolonged hospitalization, ICU stay, antineoplastic chemotherapy and indwelling urinary catheterization showed a statistically significant association with MBL production. MBL producers were 100% resistant to gentamicin, tobramycin, ofloxacin, cefoperazone, carbenicillin, ceftazidime plus clavulanic acid and meropenem. All MBL producers were sensitive to polymyxin B. Conclusions: MBL producing P. Aeruginosa is a problem in our hospital with a prevalence of 11.66%. Prolonged hospitalization, ICU stay, antineoplastic chemotherapy and indwelling catheters were the risk factors. MBL producers were resistant to most of the antibiotics tested