Invasive non-typhoidal Salmonella infections in China (1961-2024): a retrospective systematic analysis of multicentre case reports.

BACKGROUND

Salmonella can be classified as either typhoidal or non-typhoidal. The former primarily causes invasive infections, while the latter typically results in self-limiting diarrhoea. Infections caused by invasive non-typhoidal Salmonella (iNTS) are becoming an emerging global health burden, particularly in low- and middle-income regions. While they account for thousands of deaths each year, we still lack systematic analysis on their burden and epidemiology in Asia, particularly in China.

METHODS

We searched Web of Science, PubMed, China National Knowledge Infrastructure, Wanfang Data, Airiti Library, and the China Science and Technology Journal Database on 31 March 2024. The primary outcomes of interest included the spatiotemporal distribution of iNTS infection cases, patients' characteristics, and clinical outcomes. The secondary outcomes encompassed characterisation of isolates, medical histories, and medication usage. We used the Open Meta-Analyst software to estimate the case fatality rate.

RESULTS

We included 199 publications for analysis. Eastern regions of China were identified as hotspots for infection, males and children were especially susceptible populations, while trauma and metabolic diseases emerged as major risk factors associated with infection. Typhimurium, Choleraesuis, and Enteritidis were the top three serovars responsible for infections, with the bloodstream being the most frequent site of invasion. The overall case-fatality rate of iNTS in China was 8.6% (95% confidence interval = 6.8-10.4).

CONCLUSIONS

In exploring the epidemiological trends of iNTS infections in China, we observed significant risk associations with both patient characteristics and pathogen-specific determinants. There is an urgent need to establish enhanced surveillance systems and implement geographically tailored interventions+, particularly in economically underdeveloped regions.

REGISTRATION: PROSPERO (CRD42024569499).