Trends in Microbiological and Antibiotic Sensitivity Patterns in Infectious Keratitis: 10-Year Experience in Mexico City.

PURPOSE: To report the distribution and trends in microbiological and antibiotic sensitivity patterns of infectious keratitis in a 10-year period at a reference center in Mexico City. METHODS: In this retrospective observational case series, samples were obtained from corneas with a diagnosis of infectious keratitis from January 2002 to December 2011 at the Institute of Ophthalmology "Conde de Valenciana" in Mexico City. Results of cultures, stains, and specific sensitivity/resistance antibiograms for each microorganism were analyzed. RESULTS: A total of 1638 consecutive corneal scrapings were analyzed. Pathogen was recovered in 616 samples (38%), with bacterial keratitis accounting for 544 of the positive cultures (88%). A nonsignificant increasing trend in gram-negative isolates (P = 0.11) was observed. The most commonly isolated pathogen was Staphylococcus epidermidis, and the most common gram-negative isolated species was Pseudomonas aeruginosa. Methicillin-resistant Staphylococcus aureus (MRSA) was present in 45% of the S. aureus isolates; meanwhile, 53.7% coagulase-negative Staphylococcus isolates were methicillin resistant (MRCNS). Pseudomonas aeruginosa resistance to ceftazidime increased from 15% in the first period to 74% for the last 5 years of the study (P = 0.01). The overall sensitivity for vancomycin of MRSA was 87.5%, whereas 99.6% of the MRCNS were sensitive. CONCLUSIONS: There was a nonsignificant increase in the recovered gram-positive and gram-negative microorganisms over time. We observed an increased resistance to methicillin in almost half of the MRSA and MRCNS isolates.

Clinical and microbiological profile of infectious keratitis in children.

BACKGROUND: Infectious keratitis is a sight-threatening condition for children. The purpose of this study was to describe the clinical profile, risk factors and microbiological profile of infectious keratitis in children. METHODS: Retrospective review of clinical records of patients under 16 years of age with history of microbial keratitis seen at a tertiary referral center. Clinical characteristics, risk factors, visual and surgical outcomes as well as the microbiological profile are analyzed. RESULTS: Forty-one eyes of 41 patients. Mean age was 8.7 years. Time between the onset of symptoms and ophthalmological examination was 12.7 days. Predisposing factors were found in 78%; ocular trauma was the most common (25%). Visual acuity equal or worse than 20/200 at admission correlated positively with a poorer visual outcome, p=0.002. Positivity of cultures was 34%. Gram-positive bacteria were isolated in 78.5%; Staphylococcus epidermidis (28.6%) was the most common microorganism. CONCLUSIONS: Our study emphasizes the importance of a prompt diagnosis and treatment of infectious corneal ulcers in children. Trauma and contact lenses were the main predisposing factors. Gram-positive organisms were isolated in the vast majority of cases and visual outcomes are usually poor.