The role of mycobacterial infections in keratitis cases in :Çukurova region

Recently, the role of mycobacteria, especially nontuberculous mycobacteria (NTM), has become increasingly important in microbial keratitis whose differential diagnosis is challenging. Because of difficulties in routine mycobacterial identification, mycobacterial keratitis is commonly confused with fungal, herpetic and amoebic keratitis, and the worldwide incidence of this infection is low, thereby leads to the failure of treatment strategies overlooking mycobacteria and the emergence of persistent or recurrent infections. It is thought that PCR-based molecular assays, successfully performed in recent years for the mycobacterial identification and the detection of drug resistance in patients with suspected tuberculosis, will shed light on improving of rapid and accurate diagnostic protocols also for extrapulmonary mycobacterial infections such as mycobacterial keratitis when they are used subsequent to DNA extraction directly from clinical samples besides culture due to isolation difficulties in culture media. Therefore, we aimed to investigate the presence and the role of mycobacterial infections in keratitis cases in Cukurova Region. Corneal scraping samples were collected from 43 patients who are diagnosed as keratitis in Balcali Hospital, a major regional hospital, for mycobacteriological in addition to routine patological, parasitological, bacteriological and mycological examinations between September 2016 and April 2017. In the mycobacteriological research, the specimens were inoculated on Löwenstein-Jensen (LJ) and MGIT 960 liquid system, direct preparations stained with EZN method were evaluated microscopically. The presence of mycobacteria was investigated by using PCR assay with specific primers targeting hsp65 and IS6110 gene regions subsequent to DNA extraction directly from the corneal scrapings. All of the samples were negative for mycobacteria with both culture and PCR methods. Despite the fact that mycobacteria were not detected in our research which is the first study examining the presence and the role of mycobacterial infections in keratitis cases in our country by using both phenotypical and molecular methods, the expected achievement of early and accurate making diagnosis for overlooked mycobacterial keratitis will enable us to plan the treatment strategies rationally by rapid detection of drug resistance.