A clinicomicrobiological study on the importance of pseudomonas in nosocomially infected ICU patients, with special reference to metallo beta1-lactamase production.

The present study was conducted with a view to assess the burden of pseudomonal infection in ICU patients of a tertiary care teaching hospital in Uttaranchal. Of the 525 patients selected for the study, during a 1-year period, 60 patients developed features of nosocomial infection and among them Pseudomonas was isolated from one or more samples in 18 patients. The isolated strains were speciated and further characterized for determining their antibiogram and for production of beta-lactamase, extended spectrum beta-lactamase and metallo-beta-lactamase enzymes. Pseudomonas aeruginosa was the commonest species isolated (54.54%) and endotracheal suction material showed the highest bacterial yield. Polymyxin B was found to be the most effective antibiotic followed by imipenem and carbenicillin. Though no strain was found to be producing beta-lactamase and extended spectrum beta-lactamase enzymes, a total of 12 strains (54.54%) were metallo-beta-lactamase producers. For all the beta lactam antibiotics, excepting aztreonam, the metallo-beta-lactamase producers showed more resistance compared to the non-producers.