Bacterial Contamination of Veterinary Surgical Microscopes in Referral Ophthalmology Practice and a Survey of Cleaning Protocols-A Pilot Study.

Abstract

OBJECTIVE: To investigate cleaning protocols and the presence of bacteria on surgical microscopes in multidisciplinary referral centers. METHODS: Bacteriology samples from one surgical microscope were taken at each center (n = 2), from different areas (eyepieces/handles/objective lens) and at different time points (prior to and immediately after cataract surgery) and submitted for routine culture and antimicrobial susceptibility testing. A survey on surgical microscope cleaning protocols was distributed to referral centers in the UK. RESULTS: Seven isolates (three different bacterial species) were cultured from six out of 12 swabs tested. The most frequently cultured species were coagulase-negative staphylococci (5/7), and all species isolated were considered normal skin commensal bacteria of mammals. All the eyepiece samples (4/4) and half the handle samples (2/4) had a positive culture result. All objective lens samples were negative for bacterial growth. None of the cultured bacteria were multidrug-resistant, although some methicillin-resistant coagulase-negative staphylococci were identified. Survey responses from 12 referral practices were evaluated. Two centers reported that their microscopes are never regularly cleaned. Regular cleaning of the surgical microscopes occurred on days where the microscope was used (9/12), or daily regardless of use (1/12). Two out of 12 sampled the surgical microscopes for routine hospital surveillance of surface contamination. CONCLUSION: Surgical ophthalmic microscopes may be a source of opportunistic pathogens derived primarily from normal mammalian skin microbiota, particularly in areas contacted by the surgeon. Cleaning protocols of surgical microscopes in veterinary practice vary and further study into effective cleaning methods is warranted.