beta-Lactam susceptibility patterns and investigation of cephalosporin hydrolysing beta-lactamases of Gram-negative extraintestinal clinical isolates.
Of more than 3500 isolates of enterobacteriaceae, 48-69% were resistant to aminopenicillins and 11-45% to amoxycillin+clavulanic acid. Resistance to second and third generation cephalosporins was present in 11-17 and 3-8% of Escherichia coli, 47-56 and 15-52% of Klebsiella-Enterobacter, 36-57 and 16-27% of Proteus, Providencia and Morganella isolates. Pseudomonas aeruginosa strains varied in their resistance to antipseudomonal beta-lactams. Isoelectric points, inhibitor profiles and substrate profiles of beta-lactamases extracted from representatives of the resistant strains indicated that the resistance was mainly due to the hyperproduction of chromosomally encoded AmpC beta-lactamases. This was confirmed by plasmid profile and PCR investigations. Extended-spectrum beta-lactamase and metallo-penicillinase producing strains were not found. One Pseudomonas maltophilia strain produced an oxacillinase.
Gál
Z
Z
Department of Pharmacology, University of Debrecen, Debrecen, Hungary.
Szabó
D
D
Kovács
P
P
Hernádi
F
F
Tóth-Martinez
B
B
Rozgonyi
F
F
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases