Multidrug-resistant keratitis: challenging yet manageable

To study the incidence, clinical features and outcomes of multidrug-resistant (MDR) bacterial keratitis.

All cases of MDR-bacterial keratitis presenting to our institute over a period of 2 years were retrospectively analysed. Details of risk factors, size and depth of infiltrate, treatment, and outcome were noted. Antibiotic susceptibility tests were done on the ocular isolates from the culture of samples obtained from ocular infections, and resistance or sensitivity of the organisms to the commonly used antibiotics was studied.

Forty patients were diagnosed with MDR-bacterial keratitis in the study period. The mean age of patients was 50.9±25.4 years. Most common risk factors were vegetative trauma (n=12, 30.0%), followed by corneal transplantation (n=7, 17.5%) and systemic comorbidities (n=7, 17.5%). Infiltrate was small (<6 mm) in 22 (55%) and large (>6 mm) in 18 (45%) patients. It involved the superficial, mid and deep stroma in 11 (27.5%), 9 (22.5%) and 15 (37.5%) cases, respectively. Gram-negative bacilli (n=18, 45%) were the maximum, among which Pseudomonas aeruginosa (15%) was the most common. Resistance to 3 (n=17, 42.5%) and 4 (n=17, 42.5%) classes of antibiotics was the most commonly observed. One (2.5%) patient showed resistance to all seven classes of drugs tested. Complete resolution of infection was seen in 15 (37.5%) MDR patients on medical management alone. Five (12.5%) patients underwent therapeutic penetrating keratoplasty. Size of the infiltrate was found to have a significant correlation with the outcome (p=0.002).

MDR keratitis, despite being a challenge to treat, can be successfully managed by medical therapy alone, if appropriate therapy is started early in the clinical course.