title: Isolation of Streptococcus pyogenes from children with pharyngitis and emm type analysis.
abstract: BACKGROUND
  The group A streptococcus (GAS) M protein, encoded by the emm gene, acts as a major virulence factor. Emm-typing is the GAS gold standard molecular typing and is based on the DNA sequence of the nucleotides of the emm gene. The aim of the present study was to isolate GAS from patients and to detect the emm types of the isolates using emm typing.
  
  
  METHODS
  A total of 1000 throat samples were collected from patients with pharyngitis referred to Aboozar Children's Hospital in Ahvaz, Iran. We performed antimicrobial susceptibility testing on all isolates using the Kirby-Bauer disk diffusion method. Additionally, amplification of the emm gene was performed using polymerase chain reaction using the standard primers and described protocol.
  
  
  RESULTS
  From all throat samples screened, 25 isolates (2.5%) were identified as GAS. Antibiotic susceptibility testing revealed that all the GAS isolates were susceptible to penicillin and erythromycin, but 44% showed resistance to vancomycin. Based on polymerase chain reaction for the emm gene, the obtained emm types were: emm-3, observed in 20 isolates (80%); emm-1 observed in four isolates (16%); and emm-75 observed in one isolate (4%).
  
  
  CONCLUSIONS
  The result of the present study showed that penicillin and erythromycin are still the most effective antibiotics against the organism. The emm typing revealed that emm type-3 was detected in most of the isolates from patients with purulent pharyngitis. On the basis of the findings of this study, we may conclude that emm typing provides new insights on the genetic diversity of the M proteins, and is of demonstrable value for molecular studies of GAS.
authors.affiliation: Health Research Institute, Infectious, and Tropical Diseases Research Center, Ahvaz, Iran; Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Azar D
authors.initials: AD
authors.lastname: Khosravi
authors.affiliation: Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Electronic address: ebrahiminasim94@gmail.com.
authors.forename: Nasim
authors.initials: N
authors.lastname: Ebrahimifard
authors.affiliation: Health Research Institute, Infectious, and Tropical Diseases Research Center, Ahvaz, Iran; Infectious Disease Ward, Abuzar Children's Hospital, Ahvaz, Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Shamsizadeh
authors.affiliation: Department of Microbiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Shoja
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000145:classification*; D001425:Bacterial Outer Membrane Proteins / Q000145:classification*; D002352:Carrier Proteins / Q000145:classification*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D010612:Pharyngitis / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000737:chemistry / Q000187:drug effects / Q000302:isolation & purification*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C014689:streptococcal M protein
keywords: Streptococcus pyogenes; antibiotic resistance; emm typing