Resistance Patterns of Salmonella Strains in Enteric Fever: A Prospective Observational Study

Background: The global threat of enteric fever is escalating due to the increasing prevalence of extended drug resistance. In Pakistan, the situation is particularly dire as the Typhi serovar exhibits rapid mutations, advancing from multi-drug resistant (MDR) to extensively drug-resistant (XDR) strains. Objective To determine antimicrobial susceptibility of salmonella strain causing enteric fever to identify effective drugs needed to successfully treat this infection. Methods: This cross-sectional study included 189 patients who presented with symptoms of enteric fever to Lady Reading Hospital, Peshawar, between March 15 and October 31, 2023. Out of these, 150 had culture-confirmed enteric fever. Patient details and blood culture results were meticulously recorded and analyzed using SPSS version 20. Results: The cohort comprised 42 females (28%) and 108 males (72%). MDR strains were identified in 6 cases (4%) and XDR strains in 141 cases (94%). Notably, 36 of the XDR strains (24%) exhibited varied sensitivities to specific antibiotics. Meropenem and Imipenem were 100% effective across all samples. Azithromycin showed an efficacy rate of 94% (141 cases). Traditional first-line antibiotics like Ampicillin, Chloramphenicol, and Co-Trimoxazole showed high resistance rates of 98% (147 cases), 96% (144 cases), and 88% (132 cases), respectively. Among second-line antibiotics, Ceftriaxone, Cefixime, and Ciprofloxacin exhibited resistance rates of 94% (141 cases), 94% (141 cases), and 90% (135 cases), respectively. A significant association was found between gender and Azithromycin sensitivity (P=0.05). Conclusion: The results of our study highlight the increasing prevalence of azithromycin resistance among Salmonella Typhi strains, while some extensively drug-resistant (XDR) strains remain susceptible to first-line medications.