Detection of metallo-ß-lactamases-encoding genes among clinical isolates of Pseudomonas aeruginosa in a tertiary care hospital, Kathmandu, Nepal.

OBJECTIVES: This study was carried out to determine the prevalence of metallo-ß-lactamases (MBLs) producing Pseudomonas aeruginosa in imipenem-nonsusceptible isolates and to detect MBL-encoding genes among MBLs-positive isolates. RESULTS: Metallo-ß-lactamases production was detected in 68.6% isolates of P. aeruginosa with reduced susceptibility to imipenem. The bla VIM-2 gene was detected in 75% isolates and bla IMP-1 was detected in 25% isolates. All MBLs-positive isolates were multidrug resistant with a high level of resistance to imipenem (MIC 16 to ≥ 32 µg/ml), meropenem (MIC 16 to ≥ 32 µg/ml), and ceftazidime (MIC 64 to ≥ 512 µg/ml). All MBL-positive isolates were susceptible (MIC ≤ 2 µg/ml) to colistin. We found high prevalence of MBL-producing P. aeruginosa. To our knowledge this is the first report of detection of bla VIM-2 and bla IMP-1 in P. aeruginosa from Nepal. This indicates the need for awareness to prevent the spreading of these resistant isolates in hospital setting.