Lactobacillus rhamnosus from human breast milk shows therapeutic function against foodborne infection by multi-drug resistant Escherichia coli in mice.

The emergence of multi-drug resistant (MDR) pathogens greatly challenges the development of new drugs. Probiotics with the ability to inhibit MDR pathogens offer advantages over chemical antibiotics and drugs due to increased safety and fewer side effects. This study reports that Lactobacillus rhamnosus SHA113 (isolated from breast milk) significantly inhibited MDR Escherichia coli both in vitro and in vivo. MDR E. coli caused more severe inflammatory effects. TNF-α and IL-6 levels increased, while the IL-10 content decreased in serum. MDR E. coli caused disturbance in the gut microbial balance, increased the total coliform, decreased lactic acid bacteria in feces, decreased Firmicutes, and increased both Bacteroidetes and Proteobacteria. At the end of the curing treatment, ampicillin (AMP) treatment significantly reduced lactic acid bacteria compared to total coliform in feces and exacerbated the increase of Proteobacteria caused by MDR E. coli. L. rhamnosus SHA113 treatment resulted in a more significant and faster decrease of total coliform in feces and a significant decrease of Proteobacteria in the gut microbiota. The increase of total coliform in feces (caused by MDR E. coli infection) was positively correlated with IL-6 and TNF-α and negatively correlated with IL-10 in serum. However, the increase of lactic acid bacteria in feces (caused by L. rhamnosus SHA113 treatment) was negatively correlated with serum TNF-α, indicating that SHA113 exerted anti-inflammatory effects. These results suggest that L. rhamnosus SHA113 has great potential for inhibiting infections by MDR E. coli and for regulating the gut flora balance.