frequency of resistance and susceptible bacteria isolated from houseflies

background: in this study, we determine the vector competence of musca domestica with reference to the transmis­sion of susceptible and resistance bacterial strains in hospitals and slaughter house in sanandaj city, west iran. methods: totally 908 houseflies were collected to isolate bacteria from their external body based on standard proce­dures.antibiotic susceptibility testing was performed by kirby-bauer disc diffusion method on mueller hinton agar based on recommendations of clsi (formerly the national committee for clinical laboratory standards). results: from collected houseflies, 366 bacteria species were isolated. the most common isolated bacterium at hos­pitals was klebsiella pneumoniae 43.3% (n= 90) followed by pseudomonas aeruginosa 37% (n= 77), while that of slaughterhouse was proteus mirabilis . 29.1% (n= 46) followed by citrobacter freundii 28.4% (n= 45). among all the isolates from hospitals, cephalexin, chloramphenicol, ampicillin, and tetracycline, resistance rates were above 32.5% and gentamicin expressed the highest susceptibility among all the isolates from hospitals. it is worth to note that k. pneumonia e showed 61% and 44.5% resistance to cephalexin and chloramphenicol respectively. similarly, all iso­lates from slaughterhouse were more than 28% and 30% resistant to cephalexin and chloramphenicol respectively. surprisingly, among all the isolates, citrobacter freundii were highly resistant to gentamicin. conclusion: houseflies collected from hospitals and slaughterhouse may be involved in the spread of drug resistant bacteria and may increase the potential of human exposure to drug resistant bacteria.