title: An outbreak of colonization with linezolid-resistant Staphylococcus epidermidis in an intensive therapy unit.
abstract: OBJECTIVE
  To report an outbreak of colonization with linezolid-resistant Staphylococcus epidermidis in an intensive therapy unit (ITU).
  
  
  METHODS
  An outbreak of colonization with linezolid-resistant S. epidermidis affecting 16 patients in an ITU was investigated using PFGE. Environmental and staff screening was carried out as part of the investigation. Usage of linezolid in the hospital and in the ITU was reviewed. Resistant strains were screened for the presence of the G2576T mutation using PCR-RFLP genotyping. The interventions made to control the outbreak were restriction of linezolid prescription and specific infection control measures, including isolation of colonized patients and increased environmental cleaning.
  
  
  RESULTS
  Linezolid-resistant S. epidermidis strains from the 16 colonized patients were genetically related. The same strain was also cultured from environmental samples in the ITU. An increase in linezolid usage in the hospital and in the ITU occurred in the 6 months prior to the emergence of the resistant strain. Infection control measures and restriction of linezolid prescription controlled the outbreak. All resistant isolates contained the G2576T mutation.
  
  
  CONCLUSIONS
  An outbreak of colonization with linezolid-resistant S. epidermidis occurred in the ITU in our institution. The resistant strain colonized the environment and probably spread from patient to patient. The outbreak was associated with an increase in the linezolid usage in the ITU and in the institution as a whole. Restriction of linezolid usage and infection control measures were introduced to control the outbreak. The emergence of linezolid resistance in S. epidermidis has implications for the use of linezolid as a therapeutic agent.
authors.affiliation: Department of Clinical Microbiology, The Adelaide and Meath Hospital Incorporating the National Children's Hospital, Tallaght, Dublin 24, Ireland.
authors.forename: Sinéad
authors.initials: S
authors.lastname: Kelly
authors.forename: Jonathan
authors.initials: J
authors.lastname: Collins
authors.forename: Maureen
authors.initials: M
authors.lastname: Maguire
authors.forename: Catriona
authors.initials: C
authors.lastname: Gowing
authors.forename: Michelle
authors.initials: M
authors.lastname: Flanagan
authors.forename: Maria
authors.initials: M
authors.lastname: Donnelly
authors.forename: Philip G
authors.initials: PG
authors.lastname: Murphy
mesh_terms: D000081:Acetamides / Q000494:pharmacology* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D004783:Environmental Microbiology; D005260:Female; D005838:Genotype; D006801:Humans; D017053:Infection Control / Q000379:methods; D007362:Intensive Care Units; D000069349:Linezolid; D008297:Male; D008875:Middle Aged; D023303:Oxazolidinones / Q000494:pharmacology* / Q000627:therapeutic use; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013212:Staphylococcus epidermidis / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000081:Acetamides; D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D023303:Oxazolidinones; D000069349:Linezolid