Polymicrobial Keratitis: Clinical Features, Risk Factors, and Outcomes
To describe the clinical features, risk factors and outcome of microbial keratitis caused by more than one organism.
Data on microbial keratitis with significant growth of more than one organism in culture was retrieved from the microbiology department. A retrospective analysis was done. The following data was analyzed : demographic data, duration of symptoms, systemic and ocular risk factors, infiltrate characteristics, organisms isolated in culture, antimicrobial susceptibility, complications, surgical interventions, visual acuity and outcome. Complete success was defined as resolution of the infiltrate with scar formation on medical treatment alone. Partial success was defined as resolution following tissue adhesive application. Failure was defined as inadequate response to medical therapy with progressive increase of the infiltrate, corneal melting and or perforation necessitating therapeutic penetrating keratoplasties (PKP) or evisceration.
There were 34 eyes of 34 patients with polymicrobial keratitis. Almost 80% (27, 79.4%) were males, predominantly working outdoors (21,61.7%). The most common risk factors were trauma (11,32.36%), concomitant steroid usage (8,23.5%) and previous corneal transplant (7,20.59%). A combination of bacteria and fungus was more commonly isolated (23, 67.6%). Out of 64 isolates, filamentous fungi(25, 39.1%) and coagulase negative staphylococci (14, 21.9%) were the most common. Complete success was noted in 11 (39.3%) eyes, partial success in 1(3.6%) eye and failure in 16(57.1%) eyes. All the therapeutic grafts failed. Five (14.7%) eyes were eviscerated due to recalcitrant infection.
Polymicrobial keratitis with a combination of fungus and bacteria was more common and especially challenging to treat. Medical treatment may be effective however therapeutic PKP provided globe salvage at best.