Characteristics of heterotrophic endophytic bacteria in four kinds of edible raw vegetables: species distribution, antibiotic resistance, and related genes.

This study investigates the antibiotic resistance characteristics and species of heterotrophic endophytic bacteria (HEB) in four edible raw vegetables—radishes, lettuces, onions, and tomatoes—purchased from markets in Xi’an, China. Among these, radishes had the highest concentration of antibiotic-resistant HEB, while tomatoes had the lowest. The predominant antibiotic-resistant phenotypes were resistance to sulfamethoxazole (SMZ) and cefotaxime (CTX), with multi-resistant phenotypes (SMZ-TET-CTX and SMZ-TET-CIP) mainly found in radishes and lettuces. The genera Bacillus, Pseudomonas, Staphylococcus, and Stenotrophomonas were identified as the main potential hosts of antibiotic resistance genes (ARGs), including sul1, sul2, blaTEM, and class I integron (intI1), across multiple vegetable types. The findings highlight potential health risks associated with consuming raw vegetables harboring antibiotic-resistant bacteria and suggest that cooking and improved cultivation practices may help mitigate the spread of antibiotic resistance.