title: Antibiotic Susceptibility Evaluation of Group A Streptococcus Isolated from Children with Pharyngitis: A Study from Iran.
abstract: BACKGROUND
  The aim of this study was to evaluate the antibiotic susceptibility of Group A streptococcus (GAS) to antibiotics usually used in Iran for treatment of GAS pharyngitis in children.
  
  
  METHODS
  From 2011 to 2013, children 3-15 years of age with acute tonsillopharyngitis who attended Mofid Children's Hospital clinics and emergency ward and did not meet the exclusion criteria were enrolled in a prospective study in a sequential manner. The isolates strains from throat culture were identified as GAS by colony morphology, gram staining, beta hemolysis on blood agar, sensitivity to bacitracin, a positive pyrrolidonyl aminopeptidase (PYR) test result, and the presence of Lancefield A antigen determined by agglutination test. Antimicrobial susceptibility was identified by both disk diffusion and broth dilution methods.
  
  
  RESULTS
  From 200 children enrolled in this study, 59 (30%) cases were culture positive for GAS. All isolates were sensitive to penicillin G. The prevalence of erythromycin, azithromycin, and clarithromycin resistance by broth dilution method was 33.9%, 57.6%, and 33.9%, respectively. Surprisingly, 8.4% of GAS strains were resistant to rifampin. In this study, 13.5% and 32.2% of the strains were resistant to clindamycin and ofloxacin, respectively.
  
  
  CONCLUSIONS
  The high rate of resistance of GAS to some antibiotics in this study should warn physicians, especially in Iran, to use antibiotics restrictedly and logically to prevent the rising of resistance rates in future. It also seems that continuous local surveillance is necessary to achieve the best therapeutic option for GAS treatment.
authors.affiliation: Division of Pediatric Infectious Diseases, Departement of Pediatrics, Ali Asghar Children Hospital, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Shirin
authors.identifier: 0000-0002-7772-8353
authors.initials: S
authors.lastname: Sayyahfar
authors.affiliation: Division of Pediatric Infectious Diseases, Departement of Pediatrics, Pediatric Infectious Research Center, Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza
authors.identifier: 0000-0001-6054-0656
authors.initials: A
authors.lastname: Fahimzad
authors.affiliation: Department of Pediatrics, Fasa University of Medical sciences, Fasa, Iran.
authors.forename: Amir
authors.identifier: 0000-0002-2345-1598
authors.initials: A
authors.lastname: Naddaf
authors.affiliation: Traditional Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Sara
authors.identifier: 0000-0001-5050-7107
authors.initials: S
authors.lastname: Tavassoli
keywords: Antibiotic resistance; Group A streptococci; Pharyngitis; Streptococcus pyogenes; Tonsillitis