Prophage Typing of Methicillin Resistant Staphylococcus aureus Isolated from a Tertiary Care Hospital in Tehran, Iran

Staphylococcus aureus is a common cause of infections among humans andanimals and it is known as a community-acquired and nosocomial pathogen. most ofthe isolates contain lysogenic phages which are responsible for production of variousvirulence factors such as enterotoxins, staphylokinase, b-lysin, lipase, exfoliative toxina and pantone-vlaentine leukociden (pvl). all staphylococcus isolates are classified in 6groups according to their sensitivity to 27 known lysogenic phages.objectives: this study was performed to detect the presence of bacteriophage types anddetermine antibiotic resistance pattern of methicillin resistant s. aureus (mrsa) isolatesobtained from a tertiary care hospital in tehran, iran from 2008 to 2010.materials and methods: a total of 968 s. aureus isolates were collected from a tertiarycare hospital in tehran, iran and identified at the species level by pcr and biochemicaltests. susceptibility to 17 antibiotics was determined. then oxacillin and vancomycinminimum inhibitory concentration (mic) of the resistant isolates were determined.multiplex-pcr was used to detect 6 classes of prophages.results: out of the 968 isolates 247 isolates were resistant to methicillin. highest antibioticresistance was seen to penicillin (100%), erythromycin (89.8%), kanamycin (89.4%),ciprofloxacin (88.6%) and tobramycin (87.4) respectively. none of the mrsa isolatesshowed resistance to vancomycin, synercid and linezolid. mic results indicated that 46.1and 4.4% of isolates with high (mic ? 128 ?g/ml) and low level (mic ? 4 ?g/ml) showedresistance to oxacillin, respectively. four different phage types and eight patterns of prophageswere detected. all mrsa isolates contained at least one prophage. totally, 2.8, 69.2and 27.9% contained 5, 4 and 3 different prophage types, respectively. conclusions: high prevalence of different classes of prophages indicating the potentialto carry a broad spectrum of virulence factors and high oxacillin resistance were foundin the mrsa isolates. detection of sgf phage in 100% of the isolates indicates the abilityof these isolates to produce virulence factors.