Microbiologic identification of bleb-related delayed-onset endophthalmitis caused by moraxella species

To report the clinical presentation and outcome of delayed-onset endophthalmitis caused by Moraxella species and to evaluate the eubacterial polymerase chain reaction (PCR) in aqueous humor samples for the microbiologic diagnosis.

Seven patients with bleb-related delayed onset-endophthalmitis caused by Moraxella were included in a prospective multicenter study (FRIENDS group, 2004 to 2005). Eubacterial PCR followed by direct sequencing and conventional cultures were carried out on aqueous humor samples taken before the first intravitreal antibiotic injection and on vitreous samples taken during pars plana vitrectomy.

All cases were postoperative (5 after filtering surgery and 2 inadvertent filtering blebs). The mean delay of onset of endophthalmitis was 41.3 months+/-30.4 (SD) (range, 2.4 to 84.8) after surgery. Initial visual acuity was limited to light perception for 3 patients, hand motions for 2 patients, count fingers for 1 patient, and 20/125 for 1 patient. Functional recovery was variable with final visual acuity ranging from no light perception to 20/25. The eubacterial PCR carried out on aqueous humor provided microbiologic identification in all cases, whereas the cultures were negative in 6 of 7 cases. The eubacterial PCR performed on vitreous samples of 3 vitrectomized patients, after 2 intravitreal injections of antibiotics, identified Moraxella in 2 patients, whereas cultures were negative in all cases.

Delayed-onset endophthalmitis caused by Moraxella occurs predominantly after a bleb-related infection. PCR is a more sensitive technique for the microbiologic diagnosis in this context than conventional culture.