Importance of accurate sampling techniques in microbiological diagnosis of endophthalmitis

BackgroundEndophthalmitis is an ocular emergency and bacteria arethe commonest aetiological agents of infectiousendophthalmitis. Any delay in treatment will result inserious complications like complete loss of vision.Therefore, obtaining the most appropriate sample is ofparamount importance for a microbiologist to identify theaetiological agents that help the ophthalmologist inplanning treatment.ObjectiveThis study was undertaken to determine the intraocularspecimen that is most likely to yield a positive culture onmicrobiological examination.MethodsFrom 60 cases, intraocular samples were collected in theoperation theatre under anaesthesia. The samples obtainedwere aqueous humour and vitreous humour by vitreous tap,vitreous biopsy or pars plana vitrectomy. The specimenswere processed within half an hour, first by inoculating ontoculture media and then direct smear examination by Gram’sStainResultsEighty samples were obtained from 60 cases of which themost were vitreous fluid (vitreous biopsy/tap + vitrectomyfluid), i.e., 75%. Culture was positive in 88% vitrectomy fluidas compared to 74% in vitreous tap/biopsy followed by 20%in aqueous fluid.ConclusionsVitrectomy fluid appears to be the best sample for culturefrom clinically diagnosed endophthalmitis cases.