TABLE 10.

Antimicrobial regimens for prophylaxis in abdominal surgery

Surgery	Likely microorganism	First choice	Second choice	Comments
Esophageal, gastroduodenal or biliary tract	GNB, GPC	Cefazolin 1–2 g IV	Clindamycin 900 mg + gentamicin (2 mg/kg IV)	Vancomycin if MRSA suspected
Colorectal	GNB, Enterococcus, anaerobes	Cefazolin 1–2 g IV + metronidazole 500 mg IV or cefoxitin 2 g IV	Clindamycin 900 mg + gentamicin (2 mg/kg IV)	Ciprofloxacin 400 mg + metronidazole may be an alternative in selected patients
Appendectomy	GNB	Cefazolin 1–2g IV + metronidazole 500 mg IV or cefoxitin 1–2 g IV	Clindamycin or metronidazole + gentamicin (2 mg/kg IV)

GNB Gram-negative bacilli; GPC Gram-positive cocci; IV Intravenous; MRSA Methicillin-resistant Staphylococcus aureus