Original Articles 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 transmis-sion 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 proce-dures.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 hos-pitals 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. pneumoniae showed 61 % and 44.5 % resistance to cephalexin and chloramphenicol respectively. Similarly, all iso-lates 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 resistan