title: Characterization of Escherichia coli virulence genes, pathotypes and antibiotic resistance properties in diarrheic calves in Iran.
abstract: BACKGROUND
  Calf diarrhea is a major economic concern in bovine industry all around the world. This study was carried out in order to investigate distribution of virulence genes, pathotypes, serogroups and antibiotic resistance properties of Escherichia coli isolated from diarrheic calves.
  
  
  RESULTS
  Totally, 76.45% of 824 diarrheic fecal samples collected from Isfahan, Chaharmahal, Fars and Khuzestan provinces, Iran were positive for E. coli and all of them were also positive for cnf2, hlyA, cdtIII, f17c, lt, st, stx1, eae, ehly, stx2 and cnf1 virulence genes. Chaharmahal had the highest prevalence of STEC (84.61%), while Isfahan had the lowest (71.95%). E. coli serogroups had the highest frequency in 1-7 days old calves and winter season. Distribution of ETEC, EHEC, AEEC and NTEC pathotypes among E. coli isolates were 28.41%, 5.07%, 29.52% and 3.49%, respectively. Statistical analyses were significant for presence of bacteria between various seasons and ages. All isolates had the high resistance to penicillin (100%), streptomycin (98.25%) and tetracycline (98.09%) antibiotics. The most commonly detected resistance genes were aadA1, sul1, aac[3]-IV, CITM, and dfrA1. The most prevalent serogroup among STEC was O26.
  
  
  CONCLUSIONS
  Our findings should raise awareness about antibiotic resistance in diarrheic calves in Iran. Clinicians should exercise caution when prescribing antibiotics.
authors: Masoud
authors: M
authors: Shahrani
authors: Farhad Safarpoor
authors: FS
authors: Dehkordi
authors: Hassan
authors: H
authors: Momtaz
mesh_terms: D000367:Age Factors; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D002702:Chloramphenicol Resistance / Q000235:genetics; D017931:DNA Primers; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics*; D007492:Iran / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012621:Seasons; D065288:Serogroup; D012703:Serotyping; D014774:Virulence / Q000235:genetics
chemical_list: D017931:DNA Primers; D029968:Escherichia coli Proteins