cefmetazole + kanamycin + metronidazole

This is a combination of three antibiotics—cefmetazole, kanamycin, and metronidazole—used together for broad-spectrum antimicrobial prophylaxis or treatment. - **Cefmetazole** is a cephamycin antibiotic (related to second-generation cephalosporins) with activity against Gram-positive, Gram-negative, and anaerobic bacteria. It inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins[6][8]. - **Kanamycin** is an aminoglycoside antibiotic that binds irreversibly to the 30S ribosomal subunit of bacteria, causing misreading of mRNA and inhibiting protein synthesis; it is mainly effective against aerobic Gram-negative bacteria[10]. - **Metronidazole** is a nitroimidazole antibiotic effective primarily against anaerobic bacteria and protozoa; it disrupts DNA structure in susceptible organisms leading to cell death[7]. This combination has been studied as perioperative prophylaxis in colorectal surgery (oral kanamycin + oral metronidazole preoperatively plus intravenous cefmetazole perioperatively), aiming to reduce surgical site infections by covering both aerobic and anaerobic pathogens commonly encountered in gastrointestinal procedures[1].