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Letters to the Editor

Epidemiological and Microbiological Diagnosis of Suppurative Keratitis in Gangetic West Bengal, Eastern India

Thomas, Philip A MD, PhD; Kaliamurthy, J. PhD; Geraldine, P PhD

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Indian Journal of Ophthalmology: Apr–Jun 2005 - Volume 53 - Issue 2 - p 143
doi: 10.4103/0301-4738.16183
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Dear Editor,

We congratulate Basak et al1 for an excellent paper on suppurative keratitis in eastern India, from which region hitherto only two such reports have been published. We wish to offer the following insights:

1. Fungi were the commonest isolates in culture-positive cases, a situation also seen in southern India.23 The hypothesis that this possibly reflects more effective treatment of bacterial keratitis following introduction of fluoroquinolones deserves further study. However, the relatively low yield of bacteria in culture may also have been due to other factors, namely:

  1. as many as 918 patients were already taking antibiotic drops at presentation, which may have suppressed bacterial growth in culture;
  2. bacterial culture media were incubated for a maximum of 48 hours, which is too short a time to isolate slow-growing bacteria such as Nocardia species, which are important causes of keratitis; bacteria already exposed to antibiotics may also grow out slowly in culture.

2. Improved recovery of bacteria may have occurred if: the corneal scrapes had been inoculated onto the culture plates immediately after collection; all bacterial culture media had been incubated for 5 to 7 days; a broth (liquid) medium (e.g. brain heart infusion or thioglycollate broth) had also been used to recover small numbers of bacteria.

3. To our knowledge, potato dextrose agar is usually used to induce sporulation of fungi in culture and not for primary isolation of bacteria.

4. In view of the large number of patients studied, the authors could have attempted to correlate risk factors (including types of traumatizing agents) and the type of organism ultimately isolated; very few workers have attempted such correlations, and these have been in a small number of patients.

5. There are spelling and grammatical mistakes which detract from the overall excellence of the paper; for example Corynebaterium (correct spelling is Corynebacterium), Enterobactor (Enterobacter) and Aeromonus (Aeromonas) in Table 6.

1. Basak SK, Basak S, Mohanta A, Bhowmick A. Epidemiological and microbiological diagnosis of suppurative keratitis in Gangetic West Bengal, eastern India Indian J Ophthalmol. 2005;53:17–22
2. Srinivasan M, Gonzales CA, George C, Cevallos V, Mascarenhas JM, Asokan B, et al Epidemiology and aetiological diagnosis of corneal ulceration in Madurai, south India Br J Ophthalmol. 1997;8:965–71
3. Leck AK, Thomas PA, Hagan M, Kaliamurthy J, Ackuaku E, John M, et al Aetiology of suppurative corneal ulcers in Ghana and south India, and epidemiology of fungal keratitis Br J Ophthalmol. 2002;86:1211–15
© 2005 Indian Journal of Ophthalmology | Published by Wolters Kluwer – Medknow