Detection of New Delhi metallo beta lactamase-1 (NDM-1) carbapenemase in Pseudomonas aeruginosa in a single centre in southern India

BACKGROUND & OBJECTIVES New Delhi metallo β-lactamase-1 (NDM-1) producing Pseudomonas aeruginosa isolates are potential threat to human health. This study was conducted to detect the presence of bla(NDM-1) in carbapenem resistant P. aeruginosa in a tertiary care center in southern India. METHODS Sixty one carbapenem resistant clinical isolates of a total of 212 P. aeruginosa isolates cultured during the study period were screened for the presence of NDM-1by PCR. Clinical characteristics of the NDM-1 positive isolates were studied and outcome of the patients was followed up. RESULTS Of the 61 isolates, NDM-1 was detected in four isolates only. These were isolated from patients in the intensive care units and chest medicine ward. The source specimens were pus, sputum, bronchoalveolar lavage and endotracheal aspirate. The NDM-1 producers were susceptible only to polymyxin B. Only one patient responded to polymyxin B therapy, while the others succumbed to the infection. CONCLUSION These findings reveal that NDM-1 is not a major mechanism mediating carbapenem resistance in P. aeruginosa in this centre. However, continuous surveillance and screening are necessary to prevent their dissemination.