The SOS response may promote the transfer of resistance genes and plasmids by indole in Escherichia coli

Bacterial resistance is caused by a variety of causes. SOS response is the main stress mode for bacteria to adapt to environmental stress and repair damage, and the abuse of antibiotics is the main factor inducing SOS response.In order to clarify the role of SOS response in bacterial drug resistance.In this study, we induced SOS response by cefotaxime sodium,then exogenous indole, it was found that the conjugation efficiency increased significantly after SOS response and exogenous indole, at most increased 50 times,and drug-resistance genes ( bla CTX−M−9G , fosA3 )and plasmids (IncI2,IncFIB) can be transferred between bacteria in the process of SOS.Moreover,the change trends of extracellular indole level, sensor pump ( acrEF ,mtr mRNA) on cell membrane surface and tnaA mRNA were consistent with the ibpA mRNA downstream of SOS response.in which indole may play the role of "messenger".The above results show that SOS response can promote the horizontal transfer of drug-resistance genes, which is completed by regulating the level of indole, which plays a messenger role in the process of conjugation. Therefore, inhibiting SOS response by controlling the level of antibiotics in the environment, or directly interfering with the chemical synthesis of indole will help to reduce the transmission of drug resistance genes.