Antimicrobial susceptibility patterns of biofilm forming Staphylococcus aureus isolated from pigeon external ocular infections Running title: Antibiotic resistance in Staphylococcus aureus biofilm producers

Pathogenic microorganisms cause external ocular infections due to their virulence factors and hosts reduced defenses from many factors such as living condition, nutrition, genetics, physiology, hygiene, fever and age. Staphylococcus species are the most predominant isolate among the known and opportunistic pathogens in eye infections. The changing profile of microorganisms involved in ocular infections and the emergence of acquired microbial resistance dictate the need for continuous studies about bacterial profile and antimicrobial susceptibility patterns of external ocular infections. The aim of this study was to determine the prevalence of S. aureus among pigeon ocular infections and also evaluating their biofilm production ability and antibiotic resistance patterns.A total number of ۲۰ pigeon with eye infection were studied. Conjunctival specimens were collected with swabs presoaked in sterile normal saline. The growth was identified by standard laboratory procedure and susceptibility testing of the bacterial isolates were performed by the Kirby-Bauer method. The biofilm formation ability of the isolates were also detected using microtiter plate method.Out of ۲۰ specimens processed, ۲۰% pigeons had Staphylococcal eye infections. The resistance pattern of these isolates showed that Staphylococcus from pigeon samples were resistant to Tetracycline (۱۰۰%), Erythromycin (۱۰۰%), Azithromycin (۱۰۰%), Nalidixic acid (۱۰۰%), Cefazolin (۵۰%). All of Staphylococcus from pigeon samples were susceptible to Gentamycin and Furazolidone. The results of biofilm detection test showed that ۷۵% of the isolates were biofilm producers.In conclusion biofilm forming Staphylococcus aureus with multidrug resistance patterns was the most prevalent bacteria isolated form pigeon ocular infections.

Keywords:

pigeon , ocular infections , Staphylococcus aureus , biofilm , Antibiotic resistance.