Surface plasma induced elimination of antibiotic-resistant Escherichia coli and resistance genes: Antibiotic resistance, horizontal gene transfer, and mechanisms

Antibiotic-resistant bacteria (ARB) and their resistance genes (ARGs), as emerging environmental pollutants, are commonly detected in waters. Surface plasma was developed to simultaneously inactivate antibiotic resistant Escherichia coli (AR E. coli) and remove its associated ARGs in water. 7.0 log AR E. coli was inactivated after 10 min surface plasma treatment; minimal inhibitory concentration (MIC) representing antibiotic resistance profiles decreased by 96.9%, 96.9%, and 98.4% for the tested tetracycline, amoxicillin, and gentamicin, respectively. The ARGs (TetC, TetW, bla(TEM)-1, and aac(3)-II) and integmn gene (intI1, indicator of horizontal gene transfer) also decreased by 1.04, 0.61, 1.84, 2.2, and 2.3 log copies within 10 min, respectively. Oxidizing substances in the surface plasma including (OH)-O-center dot, O-1(2), H2O2, O-3, NO2-, and NO3- contributed to AR E. coli inactivation, resulting in membrane damage, biological process disruption, protein structure changes, and DNA damage. As a result, horizontal gene transfer of ARGs was inhibited by 63% after plasma treatment. Overall, surface plasma could be an effective technique to control ARB and ARGs in water.

Automated summary

The study showed that surface plasma technology can effectively inactivate antibiotic-resistant bacteria (AR E. coli) and reduce the levels of associated antibiotic resistance genes (ARGs) in water. The technology works by damaging cell membranes, disrupting biological processes, altering protein structures, and causing DNA damage to achieve bacterial inactivation, as well as inhibiting the horizontal transfer of resistance genes.