Prevalence of Tuberculosis, Drug Susceptibility Testing, and Genotyping of Mycobacterial Isolates from Pulmonary Tuberculosis Patients in Dessie, Ethiopia

Due to their initially seemingly high cost, timely diagnosis and effective treatment of tuberculosis (TB) are usually hampered by lack or shortage of resources in many high TB burden countries. However, the benefits of effective treatment can eventually outweigh those of empirical treatment. Here, a cross-sectional study was conducted on samples from smear-positive new and retreatment TB patients. Data on sociodemographic and HIV status were collected. Samples were cultured for identification, conventional drug sensitivity testing, and molecular typing by deletion typing and spoligotyping. The results showed the youth were disproportionately affected. New cases were being treated following general treatment guidelines only. Monoresistance or multiple drug resistance was found in 16.5% of new patients. Spoligotyping showed that there were 44 patterns with families H3 and T1 (lineage 4) and CAS-Delhi (lineage 3) being dominant. Some rare patterns from lineage 7 were also found. Spoligotype pattern, HIV positivity, and previous treatment were not associated with drug resistance. That the vast majority of the patients were new cases and young and the large number of these patients with mono- or multiple drug resistance indicate that most TB cases are due to recent transmissions and that urgent actions are needed to curb the transmissions.