Antimicrobial resistance patterns of Salmonella enterica serovar typhi in blood culture of typhoid fever patients: a recent trend in tertiary hospital in Enugu

Background: Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), persists as a major public health concern in developing nations, exacerbated by rising antimicrobial resistance (AMR) that undermines therapeutic options. This study examines contemporary AMR trends in S. Typhi isolates from blood cultures of typhoid patients at a tertiary care hospital in Enugu, Nigeria. Methodology: Between August 2024 and January 2025, 500 blood samples from suspected typhoid fever patients were analyzed using the BD BACTEC FX40 automated system for microbiological culture, followed by biochemical confirmation. Antimicrobial susceptibility testing was performed in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines.Results: Of the 500 samples, S. Typhi was identified in 289 (57.8%) cases. Females exhibited a higher prevalence (185 cases, 37.0%) than males (104 cases, 20.8%). The 21-28-year age group had the highest infection rate (109 cases, 21.8%), followed by children aged 5-12 years (77 cases, 15.4%) and adolescents aged 13-20 years (45 cases, 9.0%). The lowest incidence occurred in patients aged 29-36 years (27 cases, 5.4%) and those >37 years (31 cases, 6.2%). Outpatients accounted for most S. Typhi isolates (218 cases, 43.6%) compared to inpatients (71 cases, 14.2%). Antimicrobial resistance profiling revealed complete resistance (100%) to amoxicillin/clavulanic acid, meropenem, doripenem, and cefoxitin. High resistance rates (51.9%-90.3%) were observed against trimethoprim-sulfamethoxazole, tetracycline, ertapenem, ceftazidime, chloramphenicol, ceftriaxone, and colistin. In contrast, all isolates remained susceptible to levofloxacin, nitrofurantoin, and amikacin (0.0% resistance).Conclusion: This study highlights a high prevalence of multidrug-resistant S. Typhi strains, emphasizing the urgent need for antimicrobial stewardship, rational antibiotic use, and continuous resistance surveillance. Genotypic resistance monitoring and evidence-based policy adjustments are critical to optimizing treatment strategies and mitigating the spread of resistant typhoid infections.