Prevalence of and risk factors for conjunctival bacterial colonisation in adult patients undergoing elective intraocular surgery

Abstract

Abstract Purpose Bacterial colonization in the conjunctiva at the time of ocular surgery may be associated with post operative endophthalmitis. The aims of this study were to assess the risk factors for, and prevalence of bacterial colonization in the conjunctiva of adults undergoing elective intraocular surgery Methods A prospective study was conducted in the Ophthalmology Department at the ‘Emek’ Medical Center, between May 1,2006 and August 31,2007. Conjunctival cultures were obtained from the lower fornix, prior to the application of prophylactic treatment and were processed using routine techniques. Demographic, socioeconomic and medical data of our patient cohort were obtained from all participants Results Cultures were obtained from 501 patients (mean age 69.7 years), of whom bacteria grew in 203(40.5%). Coagulase Negative Staphylococcus (CNS) was the most prevalent bacteria isolated in 170 (34%) of the patients, followed by Streptococcus viridans and methicillin sensitive Stapylococcus aureus (2.8% each). In 175(35%) of the patients one type of bacteria was detected whereas more than one bacteria were detected in 28(5.5%). Independent risk factors for any bacterial growth were showering in the operating day (OR=1.70) and spring/summer seasons (OR=1.54). Preoperative showering (OR=1.76), spring/summer seasons (OR=1.55) and lack of formal education (OR=1.62), were significant independent risk factors for mixed‐type of bacterial growth in culture Conclusion Bacterial growth in culture was detected in 40% of the patients of which CNS was the most prevalent bacteria. Showering and warm weather at the operating day were significant risk factors associated with one or more types of bacterial growth.