Are spontaneously fermented plant-based foods potential sources of transferable antibiotic resistance genes?

Spontaneously fermented plant-based foods are highly valued for their unique organoleptic characteristics and presumed health benefits. However, because natural (spontaneous) fermentation does not involve the employment of starter cultures, the safety of spontaneously fermented plant-based products is not easily controlled. This review examines the presence of antibiotic resistance determinants in lactic acid bacteria (LAB) from plant-based, naturally fermented foods. Phenotypic resistance to clinically relevant antibiotics has been widely observed in LAB from a variety of food types. The larger proportion of the resistance traits reported in this review can be considered intrinsic to LAB. However, some of the identified traits, especially resistance genes to tetracycline and erythromycin, have the potential for horizontal spread. Further molecular characterization is required to determine the genetic basis of detected resistance traits that have only been assessed using phenotypic methods. The implementation of novel safety measures in the production of spontaneously fermented plant-based foods should be considered in the future.