کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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3398859 | 1222340 | 2006 | 4 صفحه PDF | دانلود رایگان |
ABSTRACTTEM-1 and TEMpUC19 β-lactamases can gain activity against ceftazidime and other expandedspectrum cephalosporins via point mutation. The frequency of emergent resistance to ceftazidime at 4 × MIC was elevated ≥ 250-fold in hyper-mutable, MutS-deficient Escherichia coli harbouring these β-lactamase genes on high- or low-copy plasmids. Moreover, although ceftazidime-resistant mutants, or those with reduced susceptibility, were selected in both the wild-type and mutS hosts, many more mutants in the mutS host showed ceftazidimase-type extended-spectrum β-lactamase (ESBL) activity. This correlated with a G–A point mutation at position 484 in the blaTEM-1 and blaTEM-pUC19 genes, conferring the Arg164His amino-acid substitution found in the TEM-29 ESBL. Non-ESBL mutants lacked changes in blaTEM.
Journal: Clinical Microbiology and Infection - Volume 12, Issue 8, August 2006, Pages 800–803