Evaluation of fungal and bacterial contaminations of patient-used ocular drops.

The aim of the present study was to investigate the incidence of fungal and bacterial contaminations of in-use eye drop products in the teaching department of ophthalmology, Imam Khomeini Hospital, Ahvaz. Two hundred and eighty seven eye drop bottles were randomly collected at the end of day 1, day 2, day 3, day 4 and day 7 of use. The eye drop residues, swabs from internal caps and droppers were inoculated onto MacConkey agar, blood agar and Sabouraud's dextrose agar. The identification of the recovered organisms was accomplished using standard microbial identification techniques. The incidence of microbial contamination of in-use eye drop products was 17.8%, with the highest rate (24.6%) and the lowest rate (9.0%) noted with day 1 and day 3 samples, respectively. The most contaminated part of the eye drop products was the caps (45.9%) followed by droppers (41.0%) and residual contents (13.1%). Considering mendicants contents, those with pilocarpine (41.7%) had the highest rate of contamination followed by atropine (31.8%), tropicamide (28.6%) and betamethasone (23.3%). Our study revealed the potential risk of contamination of in-use eye drop products in hospitals, but we did not find a direct relationship between usage duration and contamination rate.