Low-intensity ultrasound promotes the horizontal transfer of resistance genes mediated by plasmids in E. coli

Abstract

Widespread of pathogenic bacteria resistant to antibiotics has become a worldwide public health concern. Conjugative transfer between bacteria is an important mechanism for the horizontal transfer of antibiotic resistance genes. Ultrasound has been widely applied in many fields, but the effect of ultrasound on horizontal transfer of antibiotic-resistant genes is still not clear. We discovered that low-intensity (≤ 0.05 W/cm) ultrasound had no effect on bacterial growth and survival rates, but increased the permeability of cell membrane, and consequentially elevated the transfer rates of plasmid. Low-intensity ultrasound enhanced conjugation between bacteria, induced expression of conjugation genes and, and inhibited expression of global regulatory genes ,, and. In conclusion, low-intensity ultrasound promoted horizontal transfer of antibiotic-resistant genes by enhancing conjugation and regulating expression of horizontal transfer-related genes.

Understanding Stimulation of Conjugal Gene Transfer by Nonantibiotic Compounds: How Far Are We?

“…We first note that the stimulation intensity is always low to medium as the estimated increase in transfer frequencies is rarely above 4-fold and never above 8-fold (Figure 2). Therefore, the biological and environmental relevance of such a small increase is likely moderate considering that other environmental factors can affect conjugation to a similar degree: as in the case of simulated sunlight, 46 increased levels of CO 2 , 47 low-intensity ultrasound, 48 low pH, 49 urban fine particulate matter, 50 and inhalable particulate matter. 51 This degree of stimulation is much lower than the 16 000-fold stimulation caused by the transition to a biofilm lifestyle by Staphylococcus aureus carrying a prototype conjugative plasmid pGO1.…”