Characterization of Salmonella Typhi isolated from a pediatric patient: Insights from Rahim Yar Khan, Pakistan

Abstract

 Typhoid fever is an important infectious disease worldwide caused by Salmonella enterica serovar typhi and is still a challenge, especially in low- and middle-income countries. This study provides the first genomic description of an S. Typhi sample from a 12-year-old child with typhoid fever at Sheikh Zayed Hospital, Rahim Yar Khan, Pakistan. Through whole-genome sequencing (WGS), we found antimicrobial resistance (AMR) genes and virulence factors. Whole-genome sequencing (WGS) showed a multidrug-resistant phenotype. It detected important antimicrobial resistance (AMR) genes such as aph(3'')-Ib, aph(6)-Id, blaCTX-M-15, blaTEM-1B, catA1, dfrA7, qnrS1, sul1, and sul2. Notably, no carbapenem resistance genes were detected. Additionally, the isolate had several virulence factors included tviA and viaB, which are responsible for producing the Vi capsular antigen, sifA and sifB, which are linked to type II secretion systems, and typhoid toxin genes (cdtB, pltA, pltB). These findings offer important insights into the genetic makeup of local S. Typhi strains. They highlight new resistance patterns and the potential for causing disease. The study points to the urgent need for ongoing genomic monitoring, strong antimicrobial management, and focused public health actions to address the ongoing threat of drug-resistant typhoid fever in areas like Rahim Yar Khan