title: Prevalence of exfoliative toxin A and B genes in Staphylococcus aureus isolated from clinical specimens.
abstract: BACKGROUND
  The pathogenicity of Staphylococcus aureus is based on the production of various virulence factors. The frequency of these factors can markedly differ according to the geographical region.
  
  
  METHODS
  In this study, we investigated the prevalence of two frequent isoforms of exfoliative toxins and mecA genes using PCR in 197 clinical isolates obtained from clinical samples during the years 2011 and 2012. The samples were obtained from an educational hospital in northern Tehran, Iran. In addition, the antibiotic susceptibility pattern was studied for each isolate using the disc diffusion method.
  
  
  RESULTS
  In this study, 186 (94.4%), 15 (7.6%) and 172 (86.3%) of the 197 isolates expressed the eta, etb and mecA genes, respectively. In addition, 164 (88.2%) and 12 (80%) strains, which harbored the eta and etb genes, respectively, were MRSA (methicillin resistant S. aureus). Furthermore, the prevalence of the mecA, eta and etb genes was higher among the wound samples (61.2%, 55.8% and 6.09%, respectively). We observed high rates of MDR (multi drug resistance) among our isolates. A significant correlation was detected between the presence of the mecA gene and the resistance to oxacillin, gentamicin, kanamycin, erythromycin, tetracycline, cotrimoxazole, clindamycin, and cephazolin as well as the multi-drug resistant property (P<0.05). In addition to penicillin, the MDR properties and resistances to the tested antibiotics in the etb-positive strains were significantly lower compared to the etb-negative strains (P<0.05).
  
  
  CONCLUSIONS
  The prevalence of the eta, etb and mecA genes might be due to the specific geographic region.
authors.affiliation: Biology Department, Islamic Azad University of Jahrom Branch, Jahrom, Iran.
authors.forename: Roohollah Zarei
authors.initials: RZ
authors.lastname: Koosha
authors.affiliation: Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. Electronic address: imanifouladi.a@gmail.com.
authors.forename: Abbas Ali Imani
authors.initials: AA
authors.lastname: Fooladi
authors.affiliation: Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Hamideh Mahmoodzadeh
authors.initials: HM
authors.lastname: Hosseini
authors.affiliation: Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Elnaz Mehdizadeh
authors.initials: EM
authors.lastname: Aghdam
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005083:Exfoliatins / Q000235:genetics*; D005260:Female; D005798:Genes, Bacterial; D006784:Hospitals, Teaching; D006801:Humans; D007223:Infant; D007492:Iran; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D046915:Penicillin-Binding Proteins; D016133:Polymerase Chain Reaction; D015995:Prevalence; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D005083:Exfoliatins; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus
keywords: Clinical isolate; Exfoliative toxin; Multi-drug resistance; Staphylococcus aureus