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%).