title: Nursing home outbreak of invasive group a streptococcal infections caused by 2 distinct strains.
abstract: OBJECTIVE
  To identify factors contributing to a cluster of deaths from invasive group A streptococcus (GAS) infection in a nursing home facility and to prevent additional cases.
  
  
  METHODS
  Outbreak investigation.
  
  
  METHODS
  A 146-bed nursing home facility in northern Nevada.
  
  
  METHODS
  We defined a case as the isolation of GAS from a normally sterile site in a resident of nursing home A. To identify case patients, we reviewed resident records from nursing home A, the local hospital, and the hospital laboratory. We obtained oropharyngeal and skin lesion swabs from staff and residents to assess GAS colonization and performed emm typing on available isolates. To identify potential risk factors for transmission, we performed a cohort study and investigated concurrent illness among residents and surveyed staff regarding infection control practices.
  
  
  RESULTS
  Six residents met the case patient definition; 3 (50%) of them died. Among invasive GAS isolates available for analysis, 2 distinct strains were identified: emm11 (3 isolates) and emm89 (2 isolates). The rate of GAS carriage was 6% among residents and 4% among staff; carriage isolates were emm89 (8 isolates), emm11 (2 isolates), and emm1 (1 isolate). Concurrently, 35 (24%) of the residents developed a respiratory illness of unknown etiology; 41% of these persons died. Twenty-one (30%) of the surveyed employees did not always wash their hands before patient contacts, and 27 (38%) did not always wash their hands between patient contacts.
  
  
  CONCLUSIONS
  Concurrent respiratory illness likely contributed to an outbreak of invasive GAS infection from 2 strains in a highly susceptible population. This outbreak highlights the importance of appropriate infection control measures, including respiratory hygiene practices, in nursing home facilities.
authors.affiliation: Respiratory Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Atlanta, GA 30333, USA. mthigpen@cdc.gov
authors.forename: Michael C
authors.initials: MC
authors.lastname: Thigpen
authors.forename: D Michael
authors.initials: DM
authors.lastname: Thomas
authors.forename: David
authors.initials: D
authors.lastname: Gloss
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Park
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Khan
authors.forename: Vicky L
authors.initials: VL
authors.lastname: Fogelman
authors.forename: Bernard
authors.initials: B
authors.lastname: Beall
authors.forename: Chris A
authors.initials: CA
authors.lastname: Van Beneden
authors.forename: Randall L
authors.initials: RL
authors.lastname: Todd
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Greene
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003428:Cross Infection / Q000453:epidemiology / Q000635:transmission; D004196:Disease Outbreaks; D005260:Female; D006707:Homes for the Aged / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes / Q000706:statistics & numerical data; D018410:Pneumonia, Bacterial / Q000453:epidemiology* / Q000635:transmission; D012307:Risk Factors; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000635:transmission; D013297:Streptococcus pyogenes / Q000145:classification* / Q000302:isolation & purification