[Bacterial contamination of eyedrops in clinical use]

The aim of this study is to assess the importance of bacterial contamination of multidose eyedrops in a routine clinical setting.

406 eyedrop vials were cultured about one week after clinical use: 204 collected from an Ophthalmic Department, and 202 from a Nursing Home. The microbiological analysis was performed on the tip and the residual eyedrop, counting the number of bacterial colonies.

66 (16.3%) from the 406 analyzed vials were contaminated, and 5.4% out of these were severely affected. There was no significant difference between the "Ophthalmic Department" and the "Nursing Home". Commensal germs were the most frequently encountered in both groups. 4 gram negative organisms were isolated from the "Nursing Home" group.

These results are in agreement with the literature. Comparison between our two groups is difficult because the eyedrops and uses were different. However, we notice the presence of gram negative organisms in the "Nursing Home". These severe contaminations due to opportunistic pathogen organisms are rare (0.75%), probably underestimated, and represent a real infectious risk during instillation. The study of the contamination site shows that the eyedrop is more often contaminated than the tip. This can be in relation to germ desicsation and to an aspiration phenomenon of contaminated fluid at the tip level. At last, the role of preservatives is not sufficient to ensure the sterility of multidose eyedrops during their use, and this justifies safer (single dose or filtration system) eyedrop vials.