According to current safety regulations, teaching and research laboratories require one or more eyewash stations installed in case of eye exposure to harmful substances. The presence of potential pathogens on these devices may increase risk of infection when used. Thus, we have conducted a research project to evaluate the microbiota of the eye washers present in several buildings across Michigan State University’s campus. Our data showed that 90% of the surveyed eyewash stations on campus are heavily contaminated with bacteria and fungi. Thus, their use in cases of eye injury could be a matter of public health concern.
40 labs from different departments equipped with eye washers were visited and samples were taken from each of them. Sterile swabs and contact mycology plates were used to collect samples. The right side of the eyewash was designated for bacterial sampling and the left for fungal sampling. Two Blood agar plates were used for each bacterial sample collection. Both plates were incubated for 5 days at 25 °C and 37 °C respectively. Mycology plates were used for fungal collection, and these were incubated at 25 °C. Following incubation, cultures were observed using microscopy and the number of colonies were counted. Plates were determined to have heavy contamination if the number of colonies were too many to count, and low contamination if few or no colonies were grown. Gram staining was performed for bacterial cultures, and additional biochemical tests were done to identify taxonomy of bacteria. Classification of fungal colonies was determined based on colony morphology.
Heavy contamination was discovered on 90% of interrogated eye washers, while the other 10% showed low to no growth at 37 °C and 25 °C. Gram-positive rods were the most abundant bacteria present in all tested units at 37 °C. At 25 °C, the most abundant bacteria were Gram negative rods. 21 strains with high diversity were found on Mycology plates – Aspergillus, Fusarium, Mucor, Cladosporium, and Penicillium.
The presence of potentially pathogenic microbiota on eyewashers may pose a threat to the user, given that the nature of use is linked to eye injury. In future studies, sequencing will be necessary in identifying bacteria and fungi, in order to more accurately match them with know pathogenic species.