Evolving trends in the antibiotic susceptibility and resistance pattern of Salmonella species isolated from patients with suspected bloodstream infections in a clinical setting.

Abstract

Objective: To assess the evolving trends in Salmonella Typhi antibiotic susceptibility and resistance patterns from patients with suspected bloodstream infections in clinical settings. Study Design: Cross-sectional study. Setting: Department of Pathology, Khyber Teaching Hospital, Peshawar. Period: Over 6 months (January 2023 to June 2023). Methods: The study was conducted on blood culture and susceptibility samples received in the Department of Pathology, Khyber Teaching Hospital, Peshawar. The automated blood culture system VERSATREK was utilized for initial processing of the blood sample. Pathogens were labeled as Salmonella based on colony characteristics on Blood agar, McConkey agar, Salmonella Shigella agar, biochemical tests, and the API 20E kit. The antimicrobial resistance pattern was mapped out using the Disk Diffusion method as per CLSI M100-Ed33 guidelines version 23. In total, 1170 blood culture samples were analyzed. Results: The study revealed that Salmonella Typhi (96%) was the major pathogen, followed by Escherichia coli (2%), Citrobacter spps (1%), and Staphylococcus aureus (1%). Salmonella Typhi demonstrated resistance to Ampicillin (98%), Ciprofloxacin (94%), Chloramphenicol (95%), Ceftriaxone (92%), and Cotrimoxazole (62%). All Salmonella isolates were found sensitive to Meropenem (100%) and Azithromycin (100%). About 56% of the isolates were Extensively Drug-Resistant (XDR). Gender-wise distribution revealed an infection rate of 62% in male patients and 38% in female patients. Patients <20 years (82%) accounted for the majority as compared to those over 20 years (18%) of age. Conclusion: Future outbreaks of XDR typhoid are most likely to occur in Pakistan, and it continues to be the dominant circulating strain. While Cotrimoxazole is reemerging with comparatively improved sensitivity, azithromycin and meropenem continue to be available treatment options. The evolving susceptibility pattern of Salmonella isolates demands ongoing surveillance of antibiograms to optimize therapeutic protocols and control the emergence of resistant strains. Public health activities to track and mitigate the spread of XDR S. Typhi should be prioritized in this country.