Abstract
Purpose: :
Classical bacterial culture often fails to detect the infecting agent in bacterial keratitis and endophthalmitis. Our study was designed to evaluate the contribution of 16S RNA amplification using polymerase chain reaction (PCR) and nested PCR, when compared to culture, in the diagnosis of bacterial keratitis and endophthalmitis.
Methods: :
In this prospective study, we included 63 patients (24 bacterial keratitis and 39 endophthalmitis). For every patient, two samples were taken: one for bacterial culture, the other for PCR. PCR and nested PCR 16S rRNA were performed using universal primers (8/27-1510 for PCR and 91E-13BS for nested PCR) and the amplicons were thereafter sequenced.
Results: :
Culture offers a sensibility of 25%; associated to first PCR (8/27-1510), this rate increase to 31,7%, and with nested PCR (91E-13BS), we had 34,9% of identifications. We have to note that the rate of positive PCR were much better, but the sequencing rate was 59,5% only. For bacterial keratitis, culture is positive in 25% and PCR in 8%. For aqueous humor samples, culture was positive in 32%, PCR in 25% and nested PCR in 20,6%. Sequencing was possible in 76,5% for humor aqueous samples. For vitreous samples, the culture was positive in 9%, PCR in 36,3%, and nested PCR in 36,3%.
Keywords: endophthalmitis • bacterial disease • keratitis