16S rRNA PCR for differentiation of pathogenic and non-pathogenic leptospira isolates

To determine the risk factors, microbiological features, clinical features and other epidemiological characteristics of Nocardia keratitis seen at a tertiary eye care centre in south India.

We evaluated 31 patients with Nocardia keratitis seen over two years, from September 1999 to September 2001. Corneal scrapings were subjected to microscopy and culture using standard protocols.

Out of 2184 corneal ulcers cultured, 31(1.42%) were found to be Nocardia asteroides. All 31(100%) were detected correctly by 10% potassium hydroxide wet mount preparation. The highest percentage of isolates was susceptible to gentamicin (100%) followed by ciprofloxacin(93.55%). Twenty four (77.42%) patients were from rural areas; 22(70.97%) were agricultural workers; 29(93.55%) had history of trauma; 2(6.45%) had previous ocular surgery; 28(90.32%) had ocular injury with soil and sand; and 22(70.97%) had ocular injury while working in the agricultural fields. Ten (32.26%) patients presented at our institute between 15 to 35 days of onset of illness, 26(83.87%) had previous medical treatment, and 15(48.39%) patients had used traditional eye medicines. The average age of the patients was 46.16 years, with a range of 11 to 75 years. No seasonal variation was observed.

A high index of suspicion of Nocardia infection should exist in patients with a history of trauma to the eye by soil or sand. The organisms are sensitive to commonly used topical ocular antibiotics.