Antimicrobial Susceptibility Pattern of Typhoidal Salmonella species in Chittagong Medical College Hospital

Abstract

Background: Typhoid and paratyphoid fevers result from infections from Salmonella enterica serovar Typhi and Paratyphi, and the increasing prevalence of antibiotic resistance to these pathogens has raised concerns about incurable infections. It is a serious public health issue in underdeveloped nations. The widespread development of antibiotic resistance is complicating the treatment of enteric fever.

Objectives: The primary objective of this study was to determine the antimicrobial susceptibility patterns of Salmonella enterica serovar Typhi and Paratyphi in clinically suspected enteric fever patients at Chittagong Medical College Hospital.

Methodology: This cross-sectional study was conducted from July 2023 to June 2024 at the Microbiology laboratory, Chittagong Medical College. A total of 220 clinically suspected enteric fever patients from both the inpatient and outpatient departments of Paediatric and Medicine were enrolled in this study. Blood culture was carried out by the automated method. The isolates of Salmonella enterica serovar Typhi and Paratyphi were obtained from blood by culture, Gram staining, relevant biochemical tests and using specific antisera. The antimicrobial susceptibility test was done by the Modified Kirby-Bauer disc diffusion method as per the CLSI guideline of 2024. Levofloxacin sensitivity was detected by MIC as per the CLSI guideline.

Results: The isolation rate of Salmonella spp. from blood was 14.5 %, Salmonella enterica serovar Typhi was 14.05%, and Paratyphi A was 0.45%. The isolates showed 49% resistance to azithromycin, 46% to ciprofloxacin, 35% to ampicillin, 25% to chloramphenicol, 22% to cotrimoxazole and 3% to tetracycline and 2% resistant to levofloxacin. No resistance was detected in ceftriaxone and meropenem. MDR strain was detected in 12.5% isolates. The data were analysed by SPSS 29 and the results were summarized by using graphs and tables.

Conclusion: In vitro susceptibility pattern of Salmonella spp. showed the highest sensitivity against ceftriaxone and meropenem, followed by levofloxacin, tetracycline, chloramphenicol and cotrimoxazole, whereas azithromycin resistance was highest.

Bangladesh Journal of Medical Microbiology, January 2026;20 (1):59-65