Use of containers with sterilizing filter in autologous serum eyedrops

Abstract

Objective: To assess the effect of the use of containers with an adapted sterilizing filter on the contamination of autologous serum eyedrops.

Design: Prospective, consecutive, comparative, and randomized study.

Participants: Thirty patients with Sjögren syndrome.

Methods: One hundred seventy-six autologous serum containers used in home therapy were studied; 48 of them included an adapted filter (Hyabak; Thea, Clermont-Ferrand, France), and the other 128 were conventional containers. Containers equipped with a filter were tested at 7, 14, 21, and 28 days of use, whereas conventional containers were studied after 7 days of use. In addition, testing for contamination was carried out in 14 conventional containers used during in-patient therapy every week for 4 weeks. In all cases, the preparation of the autologous serum was similar. Blood agar and chocolate agar were used as regular culture media for the microbiologic studies, whereas Sabouraud agar with chloramphenicol was the medium for fungal studies.

Main outcomes measures: Microbiologic contamination of containers with autologous serum eyedrops.

Results: Only one of the containers with an adapted sterilizing filter (2.1%) became contaminated with Staphylococcus epidermidis after 1 month of treatment, whereas the contamination rate among conventional containers reached 28.9% after 7 days of treatment. The most frequent germs found in the samples were coagulase-negative Staphylococcus (48.6%). With regard the containers used in the in-patient setting, 2 (14.3%) became contaminated after 2 weeks, 5 (35.7%) became contaminated after 3 weeks, and 5 (50%) became contaminated after 4 weeks, leaving 7 (50%) that did not become contaminated after 1 month of treatment.

Conclusions: Using containers with an adapted filter significantly reduces the contamination rates in autologous serum eyedrops, thus extending the use of such container by the patients for up to 4 weeks with virtually no contamination risks.