Microbial keratitis remains a clinical challenge in urban public hospitals, and patients often seek treatment later, leading to a higher rate of complications regardless of effective therapy, according to a study in Eye Contact Lens.

In an effort to study the epidemiology, risk factors, microbiologic spectrum and treatment of microbial keratitis at an urban public hospital in comparison with adjacent private university practices, investigators at the University of Texas Southwestern Medical Center in Dallas conducted a retrospective chart review from 2009 to 2014.

The study included a total of 528 eyes with microbial keratitis, 318 in the public cohort and 210 in the private cohort. Researchers noted that contact lens wear was the most common risk factor in the public group, while ocular surface disease was the most common risk factor in the private group.

The study found the inpatient treatment rate of the public cohort was 40% compared with just 4% in the private cohort. Additionally, the perforation rate was 8% in the public group compared with 4% in the private group, and 6% of cases underwent urgent penetrating keratoplasty in the public group vs. 2% in the private group. Researchers also noted gentamicin resistance was 4.4% and tobramycin resistance was 2.9%.

Both groups demonstrated significantly better outcomes than the public population previously reported 10 years earlier, which researchers attributed to the efficacy of modern fourth-generation fluoroquinolone therapy. Although the corneal perforation and need for urgent surgery have decreased in the public patient population, these complications remain higher than the private patient cohort, they added.

“Microbial keratitis remains a challenging infection to treat in the urban public hospital patient population despite the availability of effective ophthalmic antibiotics,” the researchers said in the paper. “The risk profile of patients presenting in the public hospital setting appears to be different from those of patients presenting in the private setting, which in part reflects the expected microbiology of infectious keratitis.”

Another key trend from the study: the public patients presented later compared with their counterparts with greater access to care.

“Despite widespread clinical concern, increasing numbers of resistant organisms has not been observed at either of our institutions. Importantly, visual outcomes continue to improve in both populations despite an increasing trend to monotherapy outpatient treatment,” they concluded.