Aetiological diagnosis of microbial keratitis in South India - a study of 1618 cases

To identify the specific microbial pathogens responsible for corneal ulceration in South India and compare these profiles with other series.

All patients with infectious keratitis who presented between 20th September 1999 and 31st March 2001 were evaluated. They were examined by slit-lamp biomicroscopy and corneal scrapings were performed for cultures and smears by using standard protocols.

In the 18 months period, 1618 patients with corneal ulcerations were evaluated. Corneal cultures were found to be positive in 1126 (69.59%) patients. Of the 1618 patients, 566 (34.98%) had bacterial growth, 522 (32.26%) had fungal growth, 30 (1.85%) had mixed bacterial and fungal growth, 8 (0.49%) had Acanthamoeba species growth and the remaining 492 (30.41%) were found to be culture negative. The predominant bacterial pathogen isolated was Streptococcus pneumoniae representing 41.85%, followed by Pseudomonas aeruginosa 21.25%. The predominant fungal pathogens isolated were Fusarium species (45.85%) followed by Aspergillus species (24.37%).

Bacterial and fungal infections occurred almost with equal frequency, the predominant bacterial and fungal species isolated being Streptococcus pneumoniae and Fusarium species respectively. The findings of our study show that there is a region wise variation in the predominance of corneal pathogens. This has an important public health implication for the initiation of therapy.