Typhi from Northwest Pakistan: Molecular Strain Typing and Drug Resistance Signature.

To determine the molecular strain typing and drug resistance pattern of serovar Typhi prevalent in Northwest Pakistan. A total of 2,138 blood samples of suspected typhoid patients from Northwest Pakistan were collected followed by identification of Typhi through biochemical, serological, and species-specific gene amplification. These isolates were typed by variable-number tandem repeat (VNTR) profiling and investigated for drug resistance. The overall prevalence of Typhi was found to be 8.8% ( = 189). Thirty different VNTR strain types of Typhi were detected and the most prevalent strain types were T1 and T4, whereas T27 was less prevalent strain. Among the 189 isolates 175 (92.5%) isolates were multidrug resistant, whereas 12 (5.8%) isolates were extensively drug resistant. Resistance to imipenem in Typhi was not observed. Most of the isolates have genes encoding for resistance to fluoroquinolones, including ( = 164), ( = 160), ( = 164), ( = 160), (6')-- ( = 163), ( = 15), and ( = 3). Similarly, chloramphinicol ( = 147), azithromycin ( = 3), and co-trimoxazole ( = 145 resistance genes were detected among Typhi isolates. In this study, T1 and T4 type Typhi strains were predominantly prevalent in Northwest Pakistan. Antibiotic resistance among Typhi isolates were observed. Findings of the study would be helpful to devise an appropriate antibiotic policy to control the emergence of drug-resistant Typhi in Pakistan.