Risk Factors for Conjunctival Microorganism Colonization in Adults Undergoing Intraocular Surgery

Purpose: To assess prevalence of and risk factors for conjunctival colonization and types of organisms among adults undergoing elective intraocular surgery. Setting: Ha’Emek Medical Center, Afula, Israel. Methods: A prospective study conducted in the Ophthalmology Department at Ha’Emek Medical Center, Afula, Israel between May 1, 2006 and August 31, 2007. Included were adults undergoing elective intraocular surgeries. Conjunctival cultures were obtained from the lower fornix, prior to application of prophylactic decolonization treatment and were processed using routine microbiological 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 ± 12.0 years) of whom 52.1% were females. In 208 patients (40.5%) bacteria grew in conjunctival cultures, one type in 175 (34.9%) one, and two types in 28 (5.6%). In none fungi were isolated. Coagulase negative Staphylococcus was the most frequent bacteria isolated. By multivariate analysis, significant risk factors for conjunctival bacterial colonization were spring/summer seasons (OR 1.64, CI 1.15 - 2.36, P < 0.007), and showering on the day of the operation (OR 1.73, CI 1.11 - 2.69, P < 0.01). Conclusions: In addition to previously known risk factors for conjunctival microorganism colonization, the present study found showering on the morning of the operation, possibly related to bacteria on towels or in the eyelids and lashes, and time of year (spring/summer) perhaps resulting from higher temperature and humidity related to the presence of conjunctival bacteria to be significant in adults undergoing intraocular surgery.