Microbial Keratitis at an Urban Public Hospital: A 10-Year Update

PURPOSE: To review the epidemiology, risk factors, microbiologic spectrum, and treatment of microbial keratitis during a five-year period at an urban public hospital with comparison to similar findings a decade earlier at the same hospital. METHODS: Retrospective chart review in the 5-year interval 2009 through 2014 compared to previously reported cases 2000 through 2004 [Eye & Contact Lens 33(1): 45-49, 2007]. Comparative primary outcome measures included best-corrected visual acuity (BCVA), risk factors, culture and sensitivities, treatment, and complication rates. RESULTS: 318 eyes with microbial keratitis were identified. Contact lens wear, ocular trauma, and ocular surface diseases were the most common risk factors. The culture and recovery rates were 73% and 66% respectively. Gram-positive organisms represented 46%, gram-negative organisms 39%, fungal organisms 15%, and Acanthamoeba <1% of corneal isolates. No common corneal pathogens were resistant to aminoglycosides or vancomycin. 48% of cases were initially treated with fortified antibiotics, 43% with fluoroquinolone monotherapy, and 6% with antifungals. 40% of cases received inpatient treatment. At resolution, average BCVA was 20/82 [logMAR 0.61] with 8% of cases resulting in light perception or worse vision. The perforation rate was 8%. 6% of cases underwent urgent penetrating keratoplasty and 4% of cases underwent urgent enucleation or evisceration. Compared to the prior study, significant differences were: (1) lower culture but higher recovery rates, (2) lower admission rate, (3) more contact lens-related cases of Pseudomonas ulcers, (4) lower resistance of coagulase-negative Staphylococcus to aminoglycoside antibiotics, (5) improved BCVA at resolution, and (6) lower associated complication rates. CONCLUSION: Microbial keratitis remains a clinical challenge in the urban public hospital setting. In the past ten years, epidemiology has shifted towards greater contact lens wear with more Pseudomonal infections. Visual outcomes have not worsened despite a shift away from routine culture and inpatient care to fluoroquinolone monotherapy and outpatient management.