title: Molecular genetic analysis of 675 group A streptococcus isolates collected in a carrier study at Lackland Air Force Base, San Antonio, Texas.
abstract: Contemporary molecular genetic analysis methods have not been used to study large samples of carriage isolates of group A Streptococcus. To determine the emm types causing asymptomatic carriage and pharyngitis in a closed population, we analyzed 675 isolates recovered from a population-based surveillance study of 10,634 recruits at Lackland Air Force Base, Texas, during 4 months in 1993-1994. Strains with emm1 and emm6 alleles accounted for only 22% of the isolates recovered from asymptomatic recruits at entrance to training. However, these 2 emm types caused 69% of the pharyngitis cases identified during training and represented 51% of the isolates recovered from the throat on exit from training. Sequence analysis of the hypervariable sic gene documented that distinct emm1 subclones disseminated in specific training groups called flights. The preferential increase in the prevalence of emm1 and emm6 isolates during the 6-week training period indicates an enhanced ability of these strains to disseminate and cause disease in this population.
authors.affiliation: Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Hoe
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Fullerton
authors.forename: Mengyao
authors.initials: M
authors.lastname: Liu
authors.forename: John E
authors.initials: JE
authors.lastname: Peters
authors.forename: Gary D
authors.initials: GD
authors.lastname: Gackstetter
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Adams
authors.forename: James M
authors.initials: JM
authors.lastname: Musser
mesh_terms: D000483:Alleles; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D005787:Gene Frequency; D006801:Humans; D008297:Male; D008889:Military Personnel; D008969:Molecular Sequence Data; D010612:Pharyngitis / Q000453:epidemiology* / Q000382:microbiology; D010614:Pharynx / Q000382:microbiology; D011159:Population Surveillance; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000453:epidemiology / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000235:genetics / Q000302:isolation & purification*; D013781:Texas / Q000453:epidemiology
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; C014689:streptococcal M protein