Infectious Keratitis: Microbiological Review of 297 Cases

Abstract

Infectious keratitis is a serious ocular infection that can lead to loss of vision. The aim of this study was to investigate the microbiological characteristics of this infection at the University Hospital of Guadalajara (Spain). We retrospectively reviewed all cases diagnosed between January 2010 and December 2016. During the 7-year study period, 297 corneal scrapes corresponding to 298 patients were performed. Antibiotic treatment prior to the culture was administered in 59 cases (19.9%). Contact lens wear was the most common risk factor (33.2%). Bacterial keratitis accounted for 64.6% of cases, viral keratitis for 3.4%, and fungal keratitis for 1%. A total of 241 bacterial strains were identified. Gram-positive isolates represented 87.1%, and gram-negative 12.7%. Coagulase-negative Staphylococcus strains were the most common microorganisms isolated (30.3%). When gram-positive microorganisms were analyzed, the sensitivity prevalence rates for vancomycin (VCM), levofloxacin, gentamicin (GM), and tobramycin (TO) were 99.4%, 84.6%, 87.9%, and 88.3%, respectively. For the gram-negative organisms, the sensitivity prevalence rates for ceftazidime, ciprofloxacin, GM, and TO were 83.3%, 93.5%, 96.3%, and 100%, respectively. Our study revealed strong predominance of gram-positive microorganisms. We suggest empirically treating bacterial keratitis originating in our area with VCM and TO, especially severe bacterial keratitis and pretreated cases in the community without a clinical response.

Keywords: empirical treatment; keratitis; ocular infection; susceptibility pattern.