Study on the species-level distribution and antimicrobial resistance of Cronobacter spp. isolated from condiments and cereal-based foods across 19 provinces (autonomous regions, municipalities) in China

ObjectiveTo explore the species-level distribution and antimicrobial resistance of Cronobacter spp. isolated from condiments and cereal-based foods across 19 provinces （autonomous regions， municipalities） in China， and provide data support for analyzing the epidemiological patterns and conducting related risk assessment of this pathogen.MethodsPCR amplification and Sanger sequencing were performed to analyze the fusA gene of 457 Cronobacter isolates from food samples across 19 provinces （autonomous regions， municipalities） in 2022， and from which positive isolates were randomly selected for antimicrobial susceptibility testing.ResultsAmong the 457 Cronobacter isolates， which comprised six species， C. sakazakii and C. malonaticus accounted for 72.65% （332/457） and 16.19% （74/457）， respectively. Of 93 isolates tested for antimicrobial susceptibility， 47.31% （44/93） were resistant to at least one antibiotic. Notably， the resistance rate was 46.24% （43/93） against cefazolin， whereas resistance to ampicillin， nitrofurantoin， and trimethoprim/sulfamethoxazole was 1.08% for each antibiotic. Phylogenetic cluster analysis of fusA indicated a potential association between the phylogenetic groups of Cronobacter species and antimicrobial resistance.ConclusionThis study demonstrated that the major species of Cronobacter isolates from condiments and cereal-based foods in China were C. sakazakii and C. malonaticus. It further revealed species-specific differences in antimicrobial resistance， particularly to cephalosporins， suggesting a potential association between species-level distribution and resistance characteristics. These findings provide scientific evidence to support risk assessment and the development of control strategies for Cronobacter in relevant food products.