title: Macrolide resistance phenotypes and mechanisms of resistance in Streptococcus pyogenes in La Rioja, Spain.
abstract: One hundred and thirty seven consecutive clinical Streptococcus pyogenes isolates were evaluated for macrolide-lincosamide-streptogramin resistance (MLS). Forty of these isolates were resistant to erythromycin (29.2%), 36 of them showed the new M resistance phenotype (erythromycin resistant and clindamycin susceptible) and four isolates had the MLS(B) resistance phenotype (erythromycin and clindamycin resistant). In all 36 isolates with the M resistance phenotype, the mef gene was identified by polymerase chain reaction (PCR). In two of the four S. pyogenes isolates with the MLS(B) phenotype, both ermB and ermTR genes were found; negative results were obtained with the other two isolates which might possess a new mechanism of high level resistance against erythromycin not previously described. In summary, a high rate of erythromycin resistance was found in S. pyogenes isolates and the active efflux pump mediated by the mef gene was the mechanism most frequently involved.
authors.affiliation: Area de bioquímica y Biologia Molecular, Universidad de La Rioja, Logroño, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Portillo
authors.forename: M
authors.initials: M
authors.lastname: Lantero
authors.forename: M J
authors.initials: MJ
authors.lastname: Gastañares
authors.forename: F
authors.initials: F
authors.lastname: Ruiz-Larrea
authors.forename: C
authors.initials: C
authors.lastname: Torres
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000235:genetics; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004917:Erythromycin / Q000494:pharmacology*; D006801:Humans; D055231:Lincosamides; D018942:Macrolides; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D013030:Spain; D013297:Streptococcus pyogenes / Q000187:drug effects* / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014769:Virginiamycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D004268:DNA-Binding Proteins; C111931:ELF4 protein, human; D055231:Lincosamides; D018942:Macrolides; D014157:Transcription Factors; D014769:Virginiamycin; D004917:Erythromycin