期刊
JOURNAL OF CLINICAL MICROBIOLOGY
卷 47, 期 8, 页码 2419-2425出版社
AMER SOC MICROBIOLOGY
DOI: 10.1128/JCM.00508-09
关键词
-
类别
The acquisition of beta-lactamases in members of the Enterobacteriaceae family poses a challenge to antimicrobial susceptibility testing in the clinical laboratory. We correlated the distribution of the MICs for Klebsiella spp. and Escherichia coli with the presence of extended-spectrum beta-lactamase (ESBL) and plasmid-mediated AmpC beta-lactamase (pAmpC) genes. A total of 264 isolates were subjected to cefazolin, ceftriaxone, cefotaxime, ceftazidime, cefepime, and aztreonam agar dilution MIC determination; ESBL screening and confirmatory testing by the methods of the Clinical and Laboratory Standards Institute (CLSI); and for isolates for which the MICs of extended-spectrum cephalosporins were >= 1 mu g/ml or the MICs of cefpodoxime were > 4 mu g/ml, PCR amplification and sequencing of the ESBL and pAmpC genes. PCR was positive for 73/81 isolates (45 isolates with an ESBL gene alone, 24 isolates with a pAmpC gene alone, with 4 isolates with both genes). Compared to PCR, confirmatory testing by the CLSI method yielded a sensitivity and a specificity of 98.0 and 96.3%, respectively; there were six false-positive results and one false-negative result. No distinction in the MIC distribution was apparent between isolates with the ESBL gene and isolates with the pAmpC gene. A substantial percentage of the isolates with PCR-confirmed ESBL and/or pAmpC genes fell within the current CLSI susceptible category. For a ceftazidime, ceftriaxone, or cefotaxime MIC of >= 2 mu g/ml, a dichotomy existed between isolates with and without ESBL and pAmpC genes in most cases. This suggests that the presence of the ESBL and the pAmpC enzymes may yield similar MICs of extended-spectrum cephalosporins, many of which fall within the current nonresistant categories. Lowering of the current CLSI breakpoints for cephalosporins appears to be warranted.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据