Microbiological Identification of Delayed Onset Endophthalmitis Caused by Moraxella by Panbacterial PCR

Abstract

Purpose: : To evaluate the panbacterial PCR for the microbiological diagnosis of delayed onset endophthalmitis caused by Moraxella species.

Methods: : Prospective multicenter study of six patients with a delayed onset endophthalmitis caused by Moraxella. The panbacterial PCR amplification followed by direct sequencing was carried out (associated with the culture) on aqueous humor samples taken during the initial intra–vitreal antibiotic injection and on vitreous samples from the posterior vitrectomy.

Results: : Six patients presented a delayed onset endophthalmitis caused by Moraxella, post–operative in 5 cases (filtering surgery in 4 cases, cataract in 1 case) and post traumatic in 1 case. The mean delay of onset of the endophtalmitis was 33 months after the surgery. Initial vision was limited to light perception for 3 patients, hand motion for 2 patients, and 20/200 for 1 patient. Functional recovery was variable in our series (2 patients with more than 20/40, 2 patients at 20/200 and 2 patients with count fingers). The PCR carried out in the initial aqueous humour allowed the microbiological identification in all cases (6/6), whereas the culture was negative in 4 out of 5 cases. The panbacterial PCR carried out in the vitreous of the four vitrectomized patients, after one or more injections of intra vitreal antibiotic, identified Moraxella in one patient, whereas culture was negative in all cases. Delayed onset endophthalmitis caused by Moraxella occurs frequently in presence of a bleb–related infection. PCR is a sensitive technique for the microbiological diagnosis of the delayed onset endophthalmitis caused by Moraxella, as compared to the culture. Our data could explain the low prevalence of Moraxella reported in previous studies using microbiological culture only.

Conclusions: : The panbacterial PCR on aqueous humor samples is useful for the microbiological diagnosis of the delayed onset endophthalmitis caused by Moraxella.

Keywords: endophthalmitis • bacterial disease • inflammation