Clinical features of Streptococcus pyogenes keratitis: Case series

Purpose: To characterize the risk factors, clinical presentations, management, outcomes, and microbiological properties of Streptococcus pyogenes keratitis. Methods: Eight culture-proven cases (eight eyes) of S. pyogenes keratitis were diagnosed and treated between 2008 and 2018 at the University of Pittsburgh Medical Center (UPMC). Medical records were available for six patients, and these were reviewed to identify demographic information, systemic and ocular history, clinical presentations, antibiotic sensitivity, treatments, and outcomes of S. pyogenes isolates. Results: Of the six charts reviewed, the median patient age was 67 years and all patients were female. Four patients had a history of cataract extraction more than one year prior to presentation, one had a history of improper contact lens use, and one had basement membrane dystrophy. Two patients, who also happened to have the most serious medical comorbidities, presented with corneal perforation on initial examination. The median follow-up length was 90.5 days. Visual outcomes varied greatly between patients. Three patients had visual acuity ranging from 20/30 to 20/70, while the two patients with corneal perforation had a final visual acuity of light perception, and one patient was lost to follow-up. Five of six isolates were susceptible to fluoroquinolones and all isolates were susceptible to cefazolin. Conclusions: S. pyogenes represented an uncommon ocular pathogen at UPMC eye clinic. However, if left untreated, this infection resulted in severe ocular morbidity. The majority of patients had a benign ocular history, suggesting that S. pyogenes can infect healthy corneas in immunocompetent patients. The majority of isolates were susceptible to cefazolin and fluoroquinolones.