What is the mechanism of action of antibiotics and what is happening when mixed with alcohol?

Different actions: Too little space to go over in detail. Sufficed to say, diff classes of abx have diff mech of actions that critically affect the bacteria's ability to build a cell wall,make protein,and produce more bacteria. This results in the direct killing or maiming of bacteria. Certain abx such as metronidazole and trimethoprim-sulfamethoxazole, when mixed with alcohol, can cause forceful vomiting.