Evaluation of antibiotic resistance in Salmonella spp. isolated from clinical samples in Niamey, Niger

Background: Salmonella spp. are leading causes of gastroenteritis and typhoid fever worldwide, with hospital-acquired infections posing significant clinical challenges. The emergence of antibiotic resistance among clinical isolates has been increasingly recognized as a major contributor to treatment failure in affected patients. This study aimed to determine the prevalence and antimicrobial resistance patterns of Salmonella spp. isolated from clinical specimens at the National Hospital of Niamey, Niger. Results: A total of 3,024 stool and blood samples were collected from patients presenting with clinical signs of enteric fever or gastroenteritis. Salmonella spp. was identified via standard microbiological methods, and antimicrobial susceptibility testing was performed via the disk diffusion method on Mueller‒Hinton agar in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Extended-spectrum beta-lactamase (ESBL) production was confirmed by a double-disk synergy test, which assessed theenhancement of inhibition zones between amoxicillin/clavulanic acid and third-generation cephalosporins. Seventy-seven Salmonella isolates were recovered, yielding an overall prevalence of 2.55%. The majority of the isolates (80.52%) were obtained from children under 5 years of age. High resistance rates were observed against amoxicillin and amoxicillin/clavulanic acid (79% each). Multidrug resistance (resistance to ≥3 antibiotic classes) was detected in 25.97% of the isolates, whereas 35% were resistant to at least two antibiotics. Notably, 5.19% of the isolates were confirmed as ESBL-producing strains. Conclusion : These findings highlight the significant burden of multidrug-resistant Salmonella spp., including ESBL producers, in the clinical setting of Niamey. The high prevalence of resistance to commonly used antibiotics underscores the urgent need for enhanced antimicrobial resistance surveillance, rational antibiotic use, and infection control strategies to curb the spread of resistant strains in healthcare and community environments.