Epidemiology, Temporal Evolution and Resistance Patterns of ESBL-Producing Non-Typhoidal <em>Salmonella </em>Isolated from Blood Cultures in Kisantu, DRC (2019–2022)

Background: Antimicrobial resistance (AMR), particularly due to extended-spectrum beta-lactamases (ESBL), is a growing threat in sub-Saharan Africa. This study investigates the prevalence, epidemiological characteristics, resistance patterns and over time resistance dynamics of ESBL-producing non-typhoidal Salmonella (NTS) bacteremia in Kisantu, Democratic Republic of Congo (DRC), from 2019 to 2022. Methods: A retrospective observational study used routine bloodstream infection data from the AMR network at Saint Luc Hospital in Kisantu. Blood cultures from suspected bacteremia cases were processed using standard microbiological techniques. Bacterial identification relied on biochemical reactions. Antibiotic susceptibility testing and ESBL-NTS detection were performed by disk diffusion following Clinical and Laboratory Standards Institute guidelines. Quarterly temporal trends in ESBL-positive NTS were evaluated using logistic regression. Results: Of 19,430 blood cultures, 1,681 NTS isolates were identified, 1,568 were screened for ESBL. ESBL production was detected in 1,184 isolates (75.5%), mostly from children under 5 years (1,098/1,184; 92.7%), including nearly 72% under 24 months. ESBL prevalence increased significantly over time (β = 0.139, OR = 1.15, 95% CI: 1.11–1.19, p &lt; 0.001), rising from 14.3% in Q (Quarter) 1 2019 to 95.3% in Q3 2022. High levels of extensively drug-resistant (94.1%) and pan-drug-resistant (6.3%) isolates were observed. No carbapenem resistance was detected, and azithromycin resistance remained low (6.4%). Conclusion: ESBL-producing NTS bacteremia is rising in Kisantu, RDC, manly affecting children under 5 years. Rising resistance to key antibiotics limits treatment options and highlights the need for strengthened AMR surveillance, optimized antibiotic use, and vaccination strategies.