Clinical and Etiology Presentations of Keratitis Caused by Mixed Infectious Agents (Bacteria and Fungi)

Abstract

Introduction: Microbiological studies following the culture of corneal infiltrates are the gold standard for determining the etiology of infectious keratitis caused by bacteria or fungi; however, even if a culture of the corneal ulcer is obtained. Purpose: To investigate the predisposing factors and clinical and Etiology presentations of keratitis caused by mixed infectious agents (bacteria and fungi). Methods: This was a prospective study of cases with mixed bacterial and fungal keratitis, done between July to December 2022 in Department of Ophthalmology, Netraloy Eye Care Center, Thanthania, Bogura Sadar, Bogura, Bangladesh. Sixty (60) cases of mixed bacterial and fungal keratitis were identified. Samples (corneal swabs and scrapings) were collected aseptically from corneal ulcer patients. Isolation and identification of the microbial agents and antimicrobial susceptibility testing were done in the Microbiology and Pathology departments. Results: 38 cases (63.3%) were men, and the mean age was 54.2±9.3 years. The affected people were mostly (50; 83.3%) residing in the rural areas. 34 patients (56.7%) were involved in agricultural activities. The people of 41- 60 years of age were particularly prone to this disease (40; 66.7%). The most common predisposing factor for mixed keratitis was a history of ocular trauma (42; 70%) and 28 patients (46.7%) had a history of trauma with vegetative matter. The incidence of the disease was highest in the monsoon season, between June to September (32; 53.3%). The most common causative bacterial organisms was Staphylococcus aureus (26;43.3%) followed by Pseudomonas secies (10;16.7%) and among fungal organisms was Aspervgillus fumigates (22;36.7%) followed by Fusarium species (12;20%). Conclusion: The identification of the etiology and the predisposing factors of corneal ulcers in this region are important for the prevention and early treatment of the disease. Usually, patients with mixed bacterial and fungal keratitis have poor prognosis. Thus, when the infectious keratitis is running an atypical course or found unresponsive to the initial medical treatment, the possibility of a mixed infection by bacterial and fungal organisms should be considered.