title: Mutation of L4 ribosomal protein conferring unusual macrolide resistance in two independent clinical isolates of Staphylococcus aureus.
abstract: The aim of this study was to characterize the resistance mechanisms of two strains of Staphylococcus aureus UCN42 and UCN43 isolated from cystic fibrosis patients that displayed an unusual phenotype of resistance to macrolides. The strains were resistant to erythromycin and the 16-membered macrolide spiramycin but susceptible to clindamycin. None of the strains contained erm or msr(A) genes by PCR. Sequencing of genes encoding ribosomal targets of macrolides revealed mutations in conserved regions of the L4 ribosomal protein, a R168S mutation for S. aureus UCN43 and mutations at positions G69A and T70P for both strains. This observation extends previous reports of similar mutations in streptococci and mycoplasma to S. aureus.
authors.affiliation: Equipe EA 2128, University of Caen, Caen, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Prunier
authors.forename: Hiep N'Guyen
authors.initials: HN
authors.lastname: Trong
authors.forename: Didier
authors.initials: D
authors.lastname: Tande
authors.forename: Christine
authors.initials: C
authors.lastname: Segond
authors.forename: Roland
authors.initials: R
authors.lastname: Leclercq
mesh_terms: D000595:Amino Acid Sequence; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D006801:Humans; D018942:Macrolides / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction; D012269:Ribosomal Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D018942:Macrolides; D012269:Ribosomal Proteins; C056368:ribosomal protein L4