METALLO-ß-LACTAMASE PRODUCTION IN IMIPENEM RESISTANT STRAINS OF PSEUDOMONAS AERUGINOSA

Background: Nosocomial infections are major health issues in developing as well as developed countries. The objective of this study was to determine the frequency of MBL production in Pseudomnas aeruginosa that causes resistance to Imipenem and other ß-lactam antibiotics. Materials & Methods: A sample of 52 Imipenem resistant Pseudomnas aeruginosa colonizing or infecting the hospitalized patients were collected in Department of Pathology, Post Graduate Medical Institute, Lady Reading Hospital, Peshawar from June 2014 till May 2016. The organisms were identified by routine laboratory tests including biochemical methods and API NE System (Biomeriux) and the sensitivity pattern of commonly used antibiotics was established for each of these isolates using the disc diffusion method. Imipenem resistant strains were tested for MBL production by Imipenem-EDTA disc diffusion method. Results: The frequency of MBL activity was positive in 39 (75%) cases of Pseudomnas aeruginosa which encodes resistance to Imipenem and other ß-lactam antibiotics except monobactam. The sensitivity pattern of these antibiotics was as follows: piperacillin/ tazobactam 30.8%, amikacin and polymyxin B each 17.9%, tobramycin 12.8%, cefoperazone/ sulbactam and ceftazidime each 5.1%, ciprofloxacin, moxifloxacin, colistin sulphate, tetracycline, azithromycin and aztreonam each 2.6% and co-trimoxzole, gentamicin & rifampin each 0%. Conclusion: MBL production in P. aeruginosa confers a challenge for clinicians to treat such resistant infections with conventional antibiotics. Therefore testing each Imipenem resistant Pseudomnas aeruginosa for MBL production must be taken in routine consideration.