High prevalence of antibiotic resistance in traditionally fermented foods as a critical risk factor for host gut antibiotic resistome

Abstract

Disrupted gut microbiota as a critical risk factor for many noncommunicable diseases is largely driven by gut microbiota-impacting drugs, especially orally administrated as well as biliary excreted antibiotics. Fermented food consumption has been encouraged to replenish disrupted gut microbiota, but its overall impact on host gut health remains to be elucidated. This study examined retail traditionally fermented foods and gut microbiota of consumers of fermented foods for antibiotic resistome. Dietary intervention by fermented foods was found leading to a surge of the antibiotic resistome in gut microbiota of most human subjects. Antibiotic resistome was further illustrated in traditionally fermented food samples, and viable antibiotic resistant (AR) bacteria were recovered and highly prevalent in retail kimchi and artisan cheeses assessed in this pilot screening. Identified AR isolates included pathogens of importance in nosocomial infections such as Klebsiella pneumoniae, Enterococcus, etc., as well as commensals and lactic acid bacteria, some exhibited extremely high minimum inhibitory concentration (MIC) against antibiotics of clinical significance. Exposing fermented food microbiota to representative antibiotics further led to a boost of the corresponding antibiotic and multidrug-resistance gene pools and disturbed microbiota. These results revealed an underestimated public health risk associated with fermented foods intervention, particularly to susceptible population with gastrointestinal tract symptoms and compromised immune functions seeking gut microbiota rescue. The findings call for more comprehensive investigation and investment on the benefits and potential safety challenges associated with traditionally fermented foods, productive intervention of foodborne antibiotic resistance, and strategic movements to mitigate unnecessary damages to the host gut microbiota.