Microbial contamination of multi-use ophthalmic solutions in Kenya.

BACKGROUND/AIMS Contaminated ophthalmic solutions represent a potential cause of avoidable ocular infection. This study aimed to determine the magnitude and pattern of microbial contamination of multi-dose ocular solutions at the Department of Ophthalmology, University of Nairobi, at the Kenyatta National Hospital, Kenya. METHODS 101 vials were obtained for microbial examination after an average use of 2 weeks. The dropper tip and the residual eye drop were examined for contamination. The specimens were cultured, the number of colonies counted, the organisms identified and susceptibility testing to selected antimicrobial agents was done. RESULTS Six (6%) of the 101 analysed vials were contaminated: 4/77 vials (5%) from a multi-user setting and 2/24 vials (8%) from a single user setting. Three contaminations (3/38, 8%) occurred in vials from the eye ward, another three (3/59, 5%) in vials from the outpatient clinic. Most bacteria identified belonged to the normal commensal flora of the eye. Isolated contaminants were micrococci (n = 2), Staphylococcus epidermidis, Haemophilus sp, Bacillus sp and a Gram negative rod. The dropper tip was more often contaminated (n = 6) than the residual solution (n = 1), and only one vial showed a contamination of both the drop and the tip. CONCLUSION Our data show a contamination rate of 6%, which is in the lower range of data published on the contamination of eye drops elsewhere (0.07% to 35.8%).