title: Foodborne outbreak of group a streptococcus pharyngitis associated with a high school dance team banquet--Minnesota, 2012.
abstract: BACKGROUND
  On 20 March 2012, the Minnesota Department of Health (MDH) was notified of multiple Facebook postings suggestive of a foodborne outbreak of Group A Streptococcus (GAS) pharyngitis occurring among attendees of a high school dance team banquet. An investigation was initiated.
  
  
  METHODS
  Associations between GAS pharyngitis and specific food items were assessed among banquet attendees. Pharyngeal swabs were performed on attendees, household contacts, and food workers. Patient GAS isolates from clinical laboratories were also obtained. Pharyngeal and food specimens were cultured for GAS by the MDH Public Health Laboratory. Isolates were further characterized by pulsed-field gel electrophoresis (PFGE) and emm typing.
  
  
  RESULTS
  Among 63 persons who consumed banquet food, 18 primary illnesses occurred, yielding an attack rate of 29%. Although no food or beverage items were significantly associated with illness, pasta consumption yielded the highest relative risk (risk ratio, 3.56; 95% confidence interval, .25-50.6). GAS colonies with indistinguishable PFGE patterns corresponding to emm subtype 1.0 were isolated from 5 patients and from leftover pasta. The pasta was prepared at home by a dance team member parent; both parent and child reported GAS pharyngitis episodes 3 weeks before the banquet.
  
  
  CONCLUSIONS
  In this foodborne outbreak of GAS pharyngitis, pasta was implicated as the vehicle. Recognition of foodborne GAS illness is challenging because transmission is typically assumed to occur by respiratory spread; foodborne transmission should be considered when clusters of GAS pharyngitis patients are encountered. DNA-based typing can reveal potentially epidemiologically related isolates during GAS disease outbreaks and facilitate understanding and control of GAS disease.
authors.affiliation: Minnesota Department of Health, Saint Paul, USA. sarah_kemble@rush.edu
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Kemble
authors.forename: Amy
authors.initials: A
authors.lastname: Westbrook
authors.forename: Ruth
authors.initials: R
authors.lastname: Lynfield
authors.forename: April
authors.initials: A
authors.lastname: Bogard
authors.forename: Nicole
authors.initials: N
authors.lastname: Koktavy
authors.forename: Kelly
authors.initials: K
authors.lastname: Gall
authors.forename: Victoria
authors.initials: V
authors.lastname: Lappi
authors.forename: Aaron S
authors.initials: AS
authors.lastname: DeVries
authors.forename: Edward
authors.initials: E
authors.lastname: Kaplan
authors.forename: Kirk E
authors.initials: KE
authors.lastname: Smith
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics; D015331:Cohort Studies; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D008297:Male; D008910:Minnesota / Q000453:epidemiology; D058889:Molecular Typing; D010612:Pharyngitis / Q000453:epidemiology* / Q000382:microbiology; D010614:Pharynx / Q000382:microbiology; D012189:Retrospective Studies; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein
keywords: Streptococcus pyogenes; foodborne diseases; pharyngitis; pulsed-field gel electrophoresis; social media