Metformin Alters the Chemotaxis and Flagellar Motility of Escherichia coli

Abstract

Metformin is a biguanide molecule that is widely prescribed to treat type 2 diabetes and metabolic syndrome. Although it is known that metformin promotes the lifespan by altering intestinal microorganism metabolism, how metformin influences and alters the physiological behavior of microorganisms remains unclear. Here we studied the effect of metformin on the behavior alterations of the model organism Escherichia coli (E. coli), including changes in chemotaxis and flagellar motility that plays an important role in bacterial life. It was found that metformin was sensed as a repellent to E. coli by tsr chemoreceptors. Moreover, we investigated the chemotactic response of E. coli cultured with metformin to two typical attractants, glucose and α-methyl-DL-aspartate (MeAsp), finding that metformin prolonged the chemotactic recovery time to the attractants, followed by the recovery time increasing with the concentration of stimulus. Metformin also inhibited the flagellar motility of E. coli including the flagellar motor rotation and cell swimming. The inhibition was due to the reduction of torque generated by the flagellar motor. Our discovery that metformin alters the behavior of chemotaxis and flagellar motility of E. coli could provide potential implications for the effect of metformin on other microorganisms.

High Glucose Promotes Inflammation and Weakens Placental Defenses against E. coli and S. agalactiae Infection: Protective Role of Insulin and Metformin

“…Notably, insulin and metformin readily decreased E. coli counts and showed a better fitted defense barrier to a similar extent as explants pre-exposed to glucose 10 mM. These results agree with the experimental evidence indicating that metformin treatment increases the host resistance to E. coli infection, inhibits its microbial adherence, diminishes its response to chemoattracts and compromises its flagellar motility [ 40 , 100 , 101 ].…”

The antidiabetic drug metformin aids bacteria in hijacking vitamin B12 from the environment through RcdA

“…They found that the drug treatment is accompanied with a significant enrichment of genes responsible for bacterial environmental responses, such as ATP-bindingcassette transporters 16 . Other groups also found that metformin treatment can alter bacterial membrane function and activities in varied bacteria species 46,47 . There are a variety of bacteria colonizing the human distal ileum 48 , the majority of which lack enzymes for de novo B12 biosynthesis and rely on the uptake of exogenous B12 49 .…”

Metformin promotes bacterial surface aggregation by inhibiting the swimming motility of flagellated Escherichia coli

“…Our results showed that the reduction in swimming speed was positively correlated with metformin concentration. Our previous findings suggest that reduced torque of the flagellar motor inhibits flagellar motility [28]. The PMF powers the flagellar rotary motor of E. coli to generate torque that drives the motor rotation; thus, the motor torque can be tuned by adjusting the PMF [6,45].…”

“…To date, our group has found that metformin inhibits E. coli flagellar motor rotation and cell swimming. Motility inhibition is due to reduced torque of the flagellar motor [28]. However, the influence of motility inhibition on subsequent bacterial behaviors such as bacterial surface sensing and surface aggregation remains unclear.…”