Antibiotic susceptibility of bacterial strains isolated from patients with various infections.
OBJECTIVE
Isolates from various samples obtained during 1998 and 1999 were identified and their susceptibility to third-generation cephalosporins, monobactams and/or cephamycins studied along with any production of ESBLs.


RESULTS
Of these samples, bacteria most frequently isolated by the conventional techniques and Vitek GNI card were Escherichia coli (37%), Klebsiella pneumoniae (27%) and Enterobacter cloacae (16%). Using disk diffusion and double-disk synergy tests, we found that 71% strains produced ESBLs and 18% strains produced ESBLs and cephamycinases. Banding patterns of PCR amplification with the designed primers showed that 57% strains were capable of harbouring bla(SHV) genes. The bla(TEM), bla(CMY) and bla(AmpC) genes were harboured by 55%, 31% and 12% strains, respectively. Forty-five percent of strains contained more than two types of beta-lactamase genes. In particular, one strain contained bla(TEM), bla(SHV), bla(CMY) and bla(AmpC) genes.


CONCLUSIONS
The percentage of ESBL-producing strains was high. The most prevalent beta-lactamase gene was bla(SHV) gene. The bla(CMY) genes have been prevalent in cephamycin-resistant strains. The multidrug-resistant strains resistant to third-generation cephalosporins and cephamycins were detected in high percentage.


CONCLUSIONS
Resistance mechanisms to beta-lactams, comprising mostly extended-spectrum beta-lactamase (ESBL) production, lead to the resistance against even recently developed beta-lactams in enterobacteria, which is now a serious threat to antibiotic therapy. The high prevalence of bla(CMY) genes and multidrug-resistant genes may also cause therapeutic failure and lack of eradication of these strains by third-generation cephalosporins or cephamycins.
Lee
S H
SH
Department of Genetic Engineering, Youngdong University, Chungbuk, South Korea. sanghee@youngdong.ac.kr
Jeong
S H
SH
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002511:Cephalosporins / Q000494:pharmacology; D002513:Cephamycins / Q000494:pharmacology; D004351:Drug Resistance / Q000235:genetics*; D006801:Humans; D007239:Infections / Q000382:microbiology*; D008997:Monobactams / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002513:Cephamycins; D008997:Monobactams; D001618:beta-Lactamases