Prevalence of antibiotic resistance in invasive non-typhoidal Salmonella across 19 developing countries, 2000-2026: A systematic review and meta-analysis.

OBJECTIVE

Invasive non-typhoidal Salmonella (iNTS) infections impose a huge disease burden on developing countries, and antimicrobial resistance is growing rapidly. However, systematic data on iNTS resistance remain scarce, limiting effective vaccine design and clinical strategies. This meta-analysis was performed to estimate the antibiotic resistance prevalence of iNTS and support targeted interventions and vaccine development.

METHODS

PubMed, Embase, Web of Science, Scopus, Cochrane, CNKI, WanFang, and VIP databases were searched for eligible studies published in English between 2000 and 2026. Only studies reporting antibiotic resistance in iNTS were included. Antibiotic resistance was confirmed by samples collected from sterile sites. Resistance rates of iNTS to eight antibiotics (ampicillin, ceftriaxone, etc.) were extracted to investigate the prevalence and temporal trends of iNTS in developing countries. A random-effects model was used for data synthesis to account for heterogeneity, and various statistical analyses were conducted using R and the metafor package.

RESULTS

Forty-five studies comprising 11 447 individuals from 19 developing countries were included. The meta-analysis demonstrated substantial resistance of iNTS to multiple antibiotic classes. The highest resistance rates were observed for ampicillin (50.5%) and trimethoprim-sulfamethoxazole (39.4%), followed by chloramphenicol (28.9%), tetracycline (21.5%), and gentamicin (14.9%). Resistance was also detected to ceftriaxone (5.7%), a key first-line treatment for iNTS infections, and ciprofloxacin (5.9%), a commonly prescribed fluoroquinolone. Overall, the pooled prevalence of multidrug resistance was 41.1%, highlighting the substantial burden of antimicrobial resistance among iNTS isolates.

CONCLUSION

This study systematically reviewed the antimicrobial resistance characteristics of iNTS in developing countries, identified regional and methodological differences, and suggested standardized detection and region-targeted interventions to combat antimicrobial resistance.