Microbiology : Bacteriological and Molecular study on Staphylococcus aureus isolated from Impetigo cases in Duhok

SUMMARY A total of 204 clinical specimens were collected from patients primarily diagnosed as having impetigo while attending dermatology unit at Azadi Teaching Hospital in Duhok City from November 2008 to April 2009. An inverse relationship of was observed between the incidence of infection and age, Since the highest percentage (36.76%) was observed in the age group few months to 5 years, then decreased with the increase of age to 3.43% at the age of 65 years. Only 85 isolates (41.66%) of Staphylococcus aureus were isolated and identified using enrichment, selective media, and biochemical tests such as coagulase, catalase and DNase tests. API Staph system was also used to confirmed the biochemical characterization of 20 isolates and this showed three biotypes(1,2,3) at rates of 55%, 30% and 15% respectively according to their ability to ferment different types of sugars and other physiological characters. Results of antibiotic sensitivity test towards(13 antibiotics) for all isolates showed that all isolates (100%) were resistant to Penicillin G and most isolates were highly resistant to ampcillin, amoxicillin, cephalexin (95.29%), (94.11%), and (90.95%) respectively.