A Study of the Prevalence and Antibacterial Resistance of Coagulase Negative Staphylococci in Keratitis Infections following the use of Soft Contact Lenses

This study aimed to determine the prevalence and antibacterial resistance of coagulase negative staphylococci in keratitis infections after using soft contact lenses in patients admitted at Feiz hospital, Isfahan Iran, in 2013. In this study, 77 patients with keratitis were examined. The samples were cultured and isolation of coagulase negative staphylococcus was done using phenotypic tests and in-vitro sensitivity testing was done using Kirby-Bauer disc diffusion susceptibility method. 38 isolates were conveniently identified as coagulase negative staphylococci. 27 samples (71.1%) were resistant to penicillin, 21 (55.3%) to erythromycin, and 16 (42.1%), to tetracycline. All the isolates (100%) were sensitive to gentamicin, 36 isolates (94.7%) were sensitive to chloramphenicol, and 33 (86.8%) to ciprofloxacin. Resistance to cefoxitin was seen in 7 (18.4%). Results of this study showed that coagulase negative staphylococci were the most common agents causing contact-lens-related microbial keratitis. In addition, gentamycin, chloramphenicol and ciprofloxacin were more suitable than other antibacterial agents against this type of bacteria.