Biomedical subjects
Publications and source records attributed to Romeo Hizon.
Enterococcus faecalis G1-0247 (vancomycin MIC, 16 microg/ml) was found to harbor a vanG operon 99% identical to the vanG operon in E. faecalis BM4518. E. faecalis N03-0233 (vancomycin MIC, 16 microg/ml) was found to harbor a novel vanG operon, vanG2, on an element in a different chromosomal location than the vanG-harboring elements in G1-0247 and BM4518.
OBJECTIVES: To characterize the mechanism of cefoxitin resistance in clinical isolate Escherichia coli N99-0001. METHODS: Plasmid analysis, PCR for beta-lactamases, and sequencing of the ampC genes was carried out. An RT-PCR method was developed to determine relative ampC expression. RESULTS: Analysis of the ampC promoter region of E. coli N99-0001 revealed a T-->A mutation at -32, a C-->A mutation at -11, an insertion of a T between -20 and -21, and a 28 bp deletion including the entire attenuator. RT-PCR showed that ampC was expressed 140-fold higher in E. coli N99-0001 than in E. coli ATCC 25922. CONCLUSIONS: Cefoxitin resistance in E. coli N99-0001 was due to overexpression of ampC caused by an increase in promoter strength.