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A. J. Cariello, R. M. Passos, M. C. Z. Yu, A. L. Hofling-Lima; Epidemiological Features and Laboratory Characteristics of Keratitis at a Referral Center in Brazil - A 32-Year Review. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5040.
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© ARVO (1962-2015); The Authors (2016-present)
To describe the epidemiological features and laboratory results of infectious keratitis at a referral eye care center in Sao Paulo, Brazil.
The medical records of all patients referred to the Microbiology Laboratory in the Department of Ophthalmology at the Federal University of Sao Paulo from July 1975 to September 2007 were retrospectively reviewed. The following data were recorded: age, gender, involved eye, current use of ocular medication, history of previous trauma or surgery, contact lens wear and the results of laboratory cultures. The data were submitted to descriptive analyses, and odds ratio with 95% confidence interval and chi-square statistics were calculated for risk factors.
A total of 7,060 corneal samples from patients with keratitis were included. The age ranged from 10 days to 101 years old. Mean age was 42.1 ± 21.4 years. The male-to-female ratio was 1.5:1. The right eye was involved in 3,673 (52.0%) cases and both eyes were involved in 10 (0.14%) patients. Most patients (47.9%) were referred from the emergency room. Medical treatment was initiated in 3,614 (51.2%) patients before corneal harvesting at our service. Previous steroid use was associated with a 2.7-fold increased chance of having a positive bacterial culture (p<0.01) and previous use of antibiotics reduced by 30% the chance of having a positive bacterial culture (p<0.01). A past history of ocular surgery was observed in 1,564 (22.2%) patients. The most frequent was corneal transplantation, performed in 861 (55.0%) of these cases. Contact lens wear was reported in the medical charts of 885 (12.5%) patients and was associated with Acanthamoeba positivity (p<0.01). A history of previous ocular trauma was noted in 1,151 (16.3%) cases. Organic trauma showed a 3.8-fold greater chance of having a positive fungal culture (p<0.01). Of 6,657 (94.3%) cultures carried out, 2,958 (44.4%) had a positive result for bacterial infection, while 364 (5.5%) showed a positive result for fungal infection and 246 (3.7%) for Acanthamoeba. Staphylococcus was the most common type of bacteria isolated, representing 1,695 (50.1%) of all positive bacterial cultures, followed by Streptococcus in 459 (13.6%) and Pseudomonas in 398 (11.8%).
Infectious keratitis was most frequently caused by bacteria, and Staphylococcus was the most common agent isolated. Previous corticosteroid use seems to be a risk factor for bacterial infection, and the concomitant use of antibiotic drops could diminish positive bacterial cultures. Previous surgery, contact lens wear and ocular trauma were risk factors respectively for bacteria, Acanthamoeba and fungal keratitis.
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