Microbiological Profile Of Culture Proven Cases Of Endophthalmitis: A 10 Year Retrospective Study.

To identify the microbial aetiology of infectious endophthalmitis in a Tertiary Referral Hospital over a 10 year period.  To evaluative the presenting features, management and visual outcome of these patients. The impact of early vitrectomy in these patients was also analysed.

Ethical approval was obtained from the Clinical Research and Ethics Committee (CREC) at University Hospital Galway (Reference: C.A 2818). Following approval data was obtained on all vitreous and aqueous fluids processed for patients under the care of the Consultant Ophthalmologists at University Hospital Galway over the defined study period.

A retrospective analysis was carried out on all patients presenting between January 2011 and January 2021 with clinically diagnosed infectious endophthalmitis who underwent microbiological evaluation. Intraocular specimens (aqueous and vitreous fluids) were evaluated. The clinical characteristics, management and outcomes of these patients was also reviewed.

44 patients with endophthalmitis underwent biological analysis, of which 63% were culture positive.  Coagulase-negativestaphylococcus (CoNS) was most frequently isolated (57%), followed by Enterococcus faecalis (7%), Streptococcus viridans (7%) and Neisseria spp (7%).  The remaining organisms isolated included S. capitis, Acinetobacterbaumanii complex, H. influenzae, micrococcus luteus, S, Mitis, and S. lugdunesis. No fungal organisms were isolated. Vitreous specimens had a higher rate of culture positivity than aqueous specimens. 3 culture positive cases occurred over a four week period in February 2020, correlating with the use of face coverings during the COVID-19 period. The microbes isolated were found to be oral commensals.

Gram-positive bacteria were the major cause of infectious endophthalmitis in this series, usually following intraocular surgery. CoNS was the most common isolate. The introduction of face coverings during COVID-19 resulted in an increased rate of endophthalmitis due to throat/respiratory commensals linked with altered respiratory airflow currents. A change of protocol in the use of these coverings around ocular procedures resulted in a reduction in the rate of endophthalmitis in the 2021 study period.