Profile of Microbial Keratitis

PURPOSE:  To study the demographic characteristics, predisposing factors, and latest trends of causative organisms and to analyze the prognostic factors of visual outcome in microbial keratitis.

METHODS:  A retrospective study of patients diagnosed with microbial keratitis who required hospital admission in the period between January 2018 and December 2020 in Taiping Hospital, Perak, Malaysia.

RESULTS:  A total of 75 eyes of 74 patients who were admitted to the hospital were studied. The male to female ratio was 13.8:1. Seventy percent of patients in this study were within the productive age group between 20 and 59 years old, with a mean age of 48 years old, and 51.4% of them were labourers. Cornea foreign bodies (42, 56%) were the most common predisposing factors and were associated with good visual outcomes (P<0.005). Other significant predictors for the final visual outcome were: presenting visual acuity, size of ulcer, duration of hospitalization, and duration of resolution. The mean duration of hospitalization was seven days. Corneal scrapings were done in all cases where 44 eyes (58.7%) were found to be positive for growth. Ten eyes (13.3%) that ended up with evisceration yielded a positive result. Gram-negative bacteria was the most prevalent causative organism of infective keratitis in the local/this region. Pseudomonas sp (20, 26.7%) being the most common bacterial isolate, was seen in all four contact lens-related cases and was associated with poor visual outcome and a high rate of evisceration. Patients who developed complications such as cornea melting (9, 12%), cornea perforation (11, 14.7%) and endophthalmitis (7, 9.3%) were associated with poor visual outcomes. Likewise, patients who required therapeutic interventions such as corneal gluing, tarsorrhaphy, and penetrating keratoplasty generally had poor visual outcomes (P<0.005; P=0.000008).

CONCLUSION:  Microbial keratitis is a major cause of ocular morbidity globally. Understanding the demographic and epidemiological characteristics of microbial keratitis of the region is important in the initial prompt treatment of the patients and may eventually improve the visual outcome.