title: Lack of homology of enterococci which have high-level resistance to trimethoprim with the dfrA gene of Staphylococcus aureus.
abstract: Multiresistant enterococci were tested for susceptibility to trimethoprim (TMP). Although most enterococci are inhibited by less than or equal to 1.0 microgram/ml, the MICs for 7 of 29 selected multiresistant isolates were greater than or equal to 8 micrograms/ml, including for two beta-lactamase positive (Bla+) strains, for which the MICs of TMP were greater than 1,000 micrograms/ml, and for another Bla+ strain, for which the MIC was 128 micrograms/ml. None of five isolates tested transferred TMP resistance and none of the resistant isolates hybridized to the dfrA gene of Staphylococcus aureus. Whether TMP resistance in enterococci is due to a mutation(s) or to acquisition of a new gene is not known. Acquisition of resistance to TMP is another example of the multiple antimicrobial resistance typically displayed by enterococci.
authors.affiliation: Center for Infectious Diseases, University of Texas Medical School, Houston 77030.
authors.forename: M
authors.initials: M
authors.lastname: Frosolono
authors.forename: S L
authors.initials: SL
authors.lastname: Hodel-Christian
authors.forename: B E
authors.initials: BE
authors.lastname: Murray
mesh_terms: D013293:Enterococcus faecalis / Q000187:drug effects* / Q000235:genetics; D005839:Gentamicins / Q000494:pharmacology; D006824:Hybridization, Genetic; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics; D014295:Trimethoprim / Q000494:pharmacology*; D014296:Trimethoprim Resistance / Q000235:genetics*
chemical_list: D005839:Gentamicins; D014295:Trimethoprim