Background
Endophthalmitis is an ocular emergency and bacteria are the commonest aetiological agents of infectious endophthalmitis. Any delay in treatment will result in serious complications like  complete loss of vision. Therefore, obtaining the most appropriate sample is of paramount importance for a microbiologist to identify the aetiological agents that help the ophthalmologist in planning treatment.

Objective
This study was undertaken to determine the intraocular specimen that is most likely to yield a positive culture on microbiological examination.

Methods
From 60 cases, intraocular samples were collected in the operation theatre under anaesthesia. The samples obtained were aqueous humour and vitreous humour by vitreous tap, vitreous biopsy or pars plana vitrectomy. The specimens were processed within half an hour, first by inoculating onto culture media and then direct smear examination by Gram’s Stain

Results
Eighty samples were obtained from 60 cases of which the most were vitreous fluid (vitreous biopsy/tap + vitrectomy fluid), i.e., 75%. Culture was positive in 88% vitrectomy fluid as compared to 74% in vitreous tap/biopsy followed by 20% in aqueous fluid.

Conclusions
Vitrectomy fluid appears to be the best sample for culture from clinically diagnosed endophthalmitis cases.