The influence of needle gauge and infection source on vitreous aspirate cultures

Background/aimsWhile the Endophthalmitis Vitrectomy Study (EVS) included only post-cataract surgery patients, the methods and data from that study are widely applied in the management of endophthalmitis of all types. We sought to examine how our experience with in-office vitreous aspiration differed from the EVS in two ways: first, by reviewing microbiological culture yields from vitreous aspirates obtained using 30-gauge needles versus 25–27-gauge needles and second, by reviewing culture yields in cases of endogenous versus non-endogenous endophthalmitis.MethodsCases of endophthalmitis over a 14-year period were reviewed when vitreous tap was the initial diagnostic procedure. The data included infection source, needle size used to obtain a vitreous aspirate, organism cultured and rates of unsuccessful attempts at vitreous aspiration or dry taps.Results10 cases were endogenous endophthalmitis, while 36 cases were a mix of postoperative, post-traumatic, post-intravitreal injection and miscellaneous patients. A positive microbiological culture was obtained in 11/36 (31%) of vitreous taps using a 25–27-gauge needle and in 8/10 (80%) taps using a 30-gauge needle (p