title: Shiga Toxigenic Escherichia coli in Iranian Pediatric Patients With and Without Diarrhea: O-Serogroups, Virulence Factors and Antimicrobial Resistance Properties.
abstract: BACKGROUND
  Shiga-toxigenic Escherichia coli is an important human pathogen cause of diarrhea, hemorrhagic colitis, hemolytic uremic syndrome and thrombotic thrombocytopenic purpura in humans is a significant public health.
  
  
  OBJECTIVE
  The aim of this study was to determine the molecular characteristics and antimicrobial resistance properties of Shiga toxigenic Escherichia coli (STEC) strains with respect to their seasonal, age and geographical distributions in Iranian pediatric patients with and without diarrhea.
  
  
  METHODS
  Four hundred and eighty swab samples were taken from pediatric patients with and without diarrhea of four major provinces of Iran. Swab samples were immediately cultured and the positive culture samples were analyzed by the polymerase chain reaction (PCR) method. Finally, antimicrobial susceptibility testing was performed using the disk diffusion method in Mueller-Hinton agar.
  
  
  RESULTS
  In total, 118 out of 200 diarrheic stool samples (59%) and 77 out of 280 non-diarrheic stool samples (27.5%) were positive for E. coli. Samples taken from one to ten months old cases (73.33%) and those from Shiraz province (81.13%) were the most commonly infected. Samples taken in the summer season (91.66%) were the most commonly infected. A significant difference was shown between AEEC and EHEC strains of E. coli. The genes encoding Shiga toxins and intimin protein were the most commonly detected in all strains. O26 (33.33%), O111 (18.18%) and O91 (12.12%) serogroups had the highest incidence in patients with and without diarrhea. Prevalence of the genes that encode resistance against ampicillin (CITM), gentamicin (aac(3)-IV) and tetracycline (tetA) were 80.30%, 75.75% and 65.15%, respectively. The STEC strains harbored the highest levels of resistance against ampicillin (84.84%), gentamycin (78.78%), tetracycline (50%) and sulfamethoxazole (40.90%) antibiotics. We found that 55.08% of diarrheic and 1.29% of non-diarrheic E. coli isolates were resistant to more than six antibiotics.
  
  
  CONCLUSIONS
  Accurate control programs should be organized for antibiotic prescription especially during warmer seasons in Iran. Primary treatment of diarrheic patients with co-trimoxazole, cefotaxime and ceftriaxone is effective.
authors.affiliation: Department of Pediatric Nephrology, AJA University of Medical Sciences, Tehran, IR Iran.
authors.forename: Banafshe
authors.initials: B
authors.lastname: Dormanesh
authors.affiliation: Department of Pediatric, AJA University of Medical Sciences, Tehran, IR Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Siroosbakhat
authors.affiliation: Department of Neurosurgery, AJA University of Medical Sciences, Tehran, IR Iran.
authors.forename: Peyman
authors.initials: P
authors.lastname: Karimi Goudarzi
authors.affiliation: Department of Pediatric Neurology, Aliasghar Children Hospital, Iran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Ladan
authors.initials: L
authors.lastname: Afsharkhas
keywords: Iran; Microbial Sensitivity Tests; Shiga Toxigenic Escherichia coli; Virulence Factors