Abstract
Objective: To investigate the prevalence, antibiotic susceptibility patterns of multidrug-resistant (MDR) and extensively drug-resistant (XDR) S. Typhi strains and identify risk factors associated with typhoid fever transmission in Khairpur, Sindh, Pakistan.
Methodology: This cross-sectional study was conducted from July to December 2019 at Kausar Hospital, Khairpur, Mir’s, involving 150 clinical specimens. Initial screening used the Widal test, followed by confirmation through cell culture and biochemical testing. Data for demographic analysis was obtained using a structured questionnaire. Antibiotic susceptibility testing was performed using the Kirby-Bauer disk diffusion method, adhering to CLSI guidelines for accuracy.
Results: Preliminary screening using the Widal test identified 85 potential cases, but only 26 were confirmed through cell culture and biochemical testing. The study found that 30.7% of the isolates were MDR, resistant to first-line antibiotics such as ampicillin, chloramphenicol, and co-trimoxazole, while 7.7% were XDR, additionally resistant to fluoroquinolones and third generation cephalosporins. All isolates were sensitive to azithromycin. Demographic analysis showed that children aged 5-10 years in rural areas with limited access to clean water and poor sanitation were disproportionately affected.
Conclusion: The study found that like other parts of Sindh, XDR and MDR S. typhi also present in the Khairpur and left very limited choices for antibacterial therapy and that is very concerning. Therefore, this region needs enhanced surveillance, improved diagnostic methods, and targeted public health interventions for combating the spread of resistant S. Typhi strains in Sindh.

Key words: XDR Salmonella Typhi, MDR Salmonella Typhi, typhoid fever, antibiotic resistance, risk factors.