title: Susceptibility to chlorhexidine amongst multidrug-resistant clinical isolates of Staphylococcus epidermidis from bloodstream infections.
abstract: The emergence of Staphylococcus isolates with reduced susceptibility to chlorhexidine is being increasingly reported. We present an update to a previous report showing the continuing efficacy of chlorhexidine-based infection control measures against Staphylococcus aureus over 6 years. In this study, qacA/B genes were screened in Staphylococcus isolates collected over another 6 years in the same intensive care unit in Scotland where chlorhexidine baths form an essential component of long-term control of nosocomial infections. Consistent with our previous study, we report minimal presence of qacA/B in S. aureus strains from screening samples and bacteraemia patients but the new finding of a high proportion of qacA/B carriage in Staphylococcus epidermidis associated with reduced susceptibility to chlorhexidine. S. epidermidis isolates positive for qacA/B were clonally diverse, although 65% of isolates belonged to the multidrug-resistant (MDR) clone ST2. These findings raise concerns in relation to the selection of MDR strains by chlorhexidine and are important in the context of recent evidence emphasising the benefits of targeting bloodstream infections associated with coagulase-negative staphylococci.
authors.affiliation: School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK. Electronic address: k.hijazi@abdn.ac.uk.
authors.forename: Karolin
authors.initials: K
authors.lastname: Hijazi
authors.affiliation: School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK.
authors.forename: Indrani
authors.initials: I
authors.lastname: Mukhopadhya
authors.affiliation: Department of Medical Microbiology, Aberdeen Royal Infirmary, Aberdeen, UK.
authors.forename: Felicity
authors.initials: F
authors.lastname: Abbott
authors.affiliation: Department of Medical Microbiology, Aberdeen Royal Infirmary, Aberdeen, UK.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Milne
authors.affiliation: Department of Genetics, University of Leicester, Leicester, UK.
authors.forename: Zaaima J
authors.initials: ZJ
authors.lastname: Al-Jabri
authors.affiliation: Department of Genetics, University of Leicester, Leicester, UK.
authors.forename: Marco R
authors.initials: MR
authors.lastname: Oggioni
authors.affiliation: Department of Medical Microbiology, Aberdeen Royal Infirmary, Aberdeen, UK.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Gould
mesh_terms: D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics; D002710:Chlorhexidine / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007362:Intensive Care Units; D026901:Membrane Transport Proteins / Q000235:genetics; D058885:Multilocus Sequence Typing; D012606:Scotland; D012641:Selection, Genetic; D013203:Staphylococcal Infections / Q000382:microbiology*; D013212:Staphylococcus epidermidis / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000891:Anti-Infective Agents, Local; D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D002710:Chlorhexidine
keywords: Chlorhexidine baths; Intensive care unit; Multidrug resistance; Staphylococcus aureus; Staphylococcus epidermidis; qac genes