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.
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: A total of 6 (6%) of the 101 analyzed vials were contaminated: 4/77 vials (5%) from a multi-user setting and 2/24 vials (8%) from a single-user setting. 3 contaminations (3/38 8%) occurred in vials from the eye-ward, another 3 (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, Hemophilus sp., Bacillus sp., and a Gram negativ 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%).
- bacterial contamination
- ophthalmic medication
- ophthalmic preparation