DETECTION, MICROBIOLOGICAL CHARACTERIZATION, AND ANTIMICROBIAL SUSCEPTIBILITY PROFILE OF SALMONELLA SPP. RECOVERED FROM CHILDREN AT THE UNIVERSITY HOSPITAL FOR MOTHERS AND CHILDREN OF N’DJAMENA, CHAD

Salmonella infections remain an important cause of enteric and invasive disease in children, particularly in sub-Saharan Africa, where diagnostic and therapeutic resources may be limited. However, local data integrating microbiological detection, identification, molecular confirmation, and antimicrobial susceptibility testing of Salmonella in Chad remain scarce. This study aimed to characterize Salmonella isolates recovered from stool and blood specimens collected from hospitalized children at the University Hospital for Mothers and Children of N’Djamena, Chad. A descriptive and analytical study was conducted in 2023. Fifty stool specimens and 50 blood specimens were collected from hospitalized children. Stool specimens were subjected to direct examination, Gram staining, culture, biochemical testing, and identification using the API 20E system and APIweb. Positive blood cultures were subcultured on MacConkey agar, Chapman agar, and 5% sheep blood agar. Presumptive isolates were stored in brain–heart infusion broth supplemented with 15% glycerol. Molecular confirmation was performed following thermal DNA extraction and PCR amplification using the ST11F/ST15R primer pair. Antimicrobial susceptibility testing was performed according to the procedure documented in the source material, with minimum inhibitory concentrations (MICs) interpreted according to the reported susceptible (S) and resistant (R) categories. Salmonella was recovered from 10/50 stool specimens (20.0%) and 8/50 blood specimens (16.0%). Among stool-positive cases, 50% were children aged 0–5 years, whereas blood-positive cases were equally distributed across the four age categories. The API 20E profile 6704552 predominantly identified Salmonella spp. (89.6%), with secondary identifications of Salmonella enterica subsp. arizonae (10.3%) and Citrobacter braakii (0.1%). PCR amplification produced a band at approximately the expected product size of 421 bp. The characterized isolate exhibited resistance to ampicillin, ticarcillin, piperacillin/tazobactam, cefoxitin, ceftazidime, gentamicin, tobramycin, nalidixic acid, ciprofloxacin, ofloxacin, and trimethoprim/sulfamethoxazole, while susceptibility was reported to ertapenem, imipenem, amikacin, and nitrofurantoin. Overall, Salmonella was recovered from both stool and blood specimens in this pediatric hospital setting, and the characterized isolate displayed resistance to multiple antimicrobial classes. These findings highlight the need to strengthen standardized microbiological surveillance, antimicrobial susceptibility testing, and antimicrobial stewardship in pediatric healthcare settings in N’Djamena.