Induction of ermAMR from a clinical strain of Enterococcus faecalis by 16-membered-ring macrolide antibiotics.
We cloned the MLSB resistance determinant by PCR from a clinical isolate of Enterococcus faecalis 373, which is induced more strongly by a 16-membered-ring macrolide, tylosin, than by erythromycin. To elucidate the molecular basis of resistance of E. faecalis 373, we analyzed the cloned gene, designated ermAMR, by site-directed mutagenesis and reporter gene assay. Our results showed that an arginine-to-cysteine change in the seventh codon of the putative leader peptide endowed tylosin with resistance inducibility and that TAAA duplication enabled the control region to express the downstream methylase gene at a drastically increased level.
Oh
T G
TG
College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
Kwon
A R
AR
Choi
E C
EC
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001483:Base Sequence; D013293:Enterococcus faecalis / Q000201:enzymology* / Q000235:genetics; D004917:Erythromycin / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D015645:Tylosin / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D004917:Erythromycin; D015645:Tylosin