DIVERSITY OF BETA-LACTAMASES AMONG KLEBSIELLA-PNEUMONIAE STRAINS ISOLATED IN A UNIVERSITY HOSPITAL IN GREECE

Among 48 clinical strains of Klebsiella pneumoniae isolated in a unive rsity hospital in Northern Greece, 29 (60.4%) exhibited resistance to third generation cephalosporins (3GC) and aztreonam. Thirty-two (66.7% ) of the isolates were found resistant to the combination of ampicilli n/sulbactam and six (12.5%) exhibited resistance to all the above anti biotics plus cefoxitin. Resistance to 3GC was related mostly with the presence of a beta-lactamase exhibiting pI 8.2 and substrate profile o f an SHV-5 type enzyme and rarely (in two of the cefoxitin resistant s trains) with the presence of plasmid-mediated class C cephalosporinase s. Resistance to the ampicillin/sulbactam combination was associated w ith the presence of a beta-lactamase with pI 5.4, presumably represent ing a TEM-1 beta-lactamase. These findings record a diversity of beta- lactamases and explain, at least partly, the various beta-lactam resis tance patterns observed in our K. pneumoniae sample.