Ocular Microbiology and Immunology Group
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2015 OMIG Abstract 9

Microbial Keratitis at an Urban Public Hospital: A 10-year update
David T. Truong, M.D., H. Dwight Cavanagh, M.D., Ph.D.
Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX

Purpose: To review the recent epidemiology, risk factors, microbiology, and treatment of microbial keratitis at an urban public hospital with comparison to similar findings a decade earlier at the same hospital. 

Methods: Retrospective chart review of cases in the 5-year interval 2009 through 2014 compared to previously published cases 2000 through 2004 [Eye & Contact Lens 33(1): 45–49, 2007]. Primary outcome measures included vision, risk factors, culture and sensitivities, treatment, and complication rates. 

Results: From 2009-2014, 165 eyes with microbial keratitis have been identified. Contact lens wear, ocular trauma, and pre-existing ocular surface diseases were the most common risk factors.  The culture and recovery rates were 66% and 69% respectively.  Gram-positive organisms represented 59%, gram-negative organisms 30%, fungal organisms 10%, and acanthamoeba <1% of corneal isolates.  No common corneal pathogens were resistant to aminoglycosides or vancomycin.  Fluoroquinolone resistance was not routinely determined for most cultures.  35% of cases were initially treated with fortified antibiotics, 51% with fluoroquinolone monotherapy, and 5% with antifungals.  24% of cases were admitted to the hospital.  At resolution, average BCVA was 20/63 [logMAR 0.50] with 10% of cases resulting in light perception or worse vision.  The perforation rate was 6%. 10% of cases underwent urgent penetrating keratoplasty and 2% of cases underwent urgent enucleation or evisceration.  Compared to prior study, significant differences were: (1) lower culture but higher recovery rate, (2) lower admission rate, (3) more gram-positive and fewer gram-negative organisms, (4) lower resistance of coagulase-negative staphylococcus to aminoglycoside antibiotics, (5) improved BCVA at resolution [20/231], and (6) lower associated complication rates.

Conclusions: Microbial keratitis remains a challenging infection to treat in the urban public hospital setting.  The microbiologic spectrum has shifted over the past decade towards gram-positive and away from gram-negative organisms.  Patient outcomes have not worsened despite a shift away from routine culture and inpatient treatment. 

Supported by NIH EY020799, Research to Prevent Blindness

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