Purpose
Geographical differences play a major role to the clinical and microbiological characteristics of infectious keratitis. The purpose of this observational retrospective study is to present these aspects of the infectious keratitis found in Mexico to be able to establish empiric treatment guidelines.
Methods
Patient records from January 2010 to November of 2014 were revised. Cases in which corneal scrape cultures were made were selected. Variables studied included were: gender, age, time of presentation to medical attention, visual acuity, microbiologic agent encountered, comorbidities, and complications.
Results
Twenty-eight cases of microbial keratitis with corneal scrape culture were found. Male:Female ratio was 18:10 respectively and age at presentation varied from 2 to 85 years. The most commonly encountered microbiologic agent was Pseudomona aeruginosa, found in 8 patients; 5 cases were positive to fungal agents, 2 for Fusarium spp and 2 for Candida spp; S. pneumonie was found in two patients, Acantamoeba spp in one patient, and Corynebacerium matruchotti in another patient. Other isolated microorganisms included M. catharralis, H. influenzae, A. xyloxidans, Aspergillus, and S. marcescens. Twenty one percent of the cultures were negative.<br /> Ocular trauma was associated to 32.1% of the cases, including vegetal and metallic objects. Diabetes Mellitus was found as a comorbidity in 32.1% of the cases and one case was HIV positive. Only 3 contact lens users were identified in the total of cases. Time from the beginning of symptoms to time of medical attention ranged from 1 to 60 days. Patients who waited more time to get medical attention were those with fungal and parasitic infections. Gram-negative bacteria dominated the microbiologic pattern being the encountered organism in 36.3% of the positive cultures. Four patients had corneal perforation, two of them associated to Pseudomona aeruginosa.
Conclusions
This study revised the epidemiology of microbial keratitis in northern Mexico. The microbiologic pattern encountered varies importantly from that in other geographic zones, especially in the unusually high Gram-negative predominance. There was a tight relation between microbial keratitis with trauma and Diabetes Mellitus. This study will aid the generation of new treatment guidelines in the geographic zone studied.