Extended-spectrum beta-lactamase-conferring transferable resistance to different antimicrobial agents in Enterobacteriaceae isolated from bloodstream infections.
Twenty (18.5%) out of 108 clinical isolates of the family Enterobacteriaceae responsible for bloodstream infection were extended-spectrum beta-lactamase (ESBL)-positive in two screening tests, the double disk synergy test and the Oxoid Combination Disk method. Eleven out of the 20 ESBL-positive isolates transferred oxyimino-beta-lactam resistance to E. coli K12 C600 recipient strain with a frequency of 10(-8) - 10(-1) per donor cell. PCR analysis revealed that the majority of the transconjugants (9 of 11) express CTX-M-type beta-lactamases. Donor strains and their transconjugants displayed susceptibility patterns typical of ESBL producers. They were resistant to oxyimino-beta-lactams but susceptible to clavulanic acid and carbapenems. Resistances to aminoglycosides, tetracycline and mercuric chloride were, in some cases, co-transferred with oxyimino-beta-lactam resistance, suggesting that various resistance determinants were carried by the same conjugative plasmids.
Franiczek
R
R
Department of Microbiology, University of Medicine in Wrocław, 50 368 Wrocław, Poland. romanf@mbio.am.wroc.pl
Krzyzanowska
B
B
Dolna
I
I
Mokracka
G
G
Szufnarowski
K
K
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology*; D003227:Conjugation, Genetic; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D022761:Gene Transfer, Horizontal; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D016133:Polymerase Chain Reaction; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*; D047090:beta-Lactams / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases