Table 4.

Examples of empiric, definitive, and duration antibiotic prescribing guidelines.

Empiric Guidelines
Diagnosis	Suspected Pathogen	Empiric Therapy	Duration of Therapy
Abdominal infection, community-acquired (e.g., cholecystitis, cholangitis, diverticulitis, abscess); NOTE: add gentamicin if MDRO suspected or identified	Enterobacteriaceae Bacteroides sp. Enterococci Streptococci	Preferred: • Ceftriaxone IV 1 g q24h + metronidazole IV or PO 500 mg q8h • +/− gentamicin IV 5 mg/kg q24h Alternative: • piperacillin/tazobactam IV 4.5 g q6h • cefepime IV 2 g q12h + metronidazole IV or PO 500 mg q8h + IV 5mg/kg q24hr • imipenem IV 1g q8h Oral options for outpatient therapy: • ofloxacin PO 400 mg q12h + metronidazole PO 500 mg q12h • moxifloxacin PO 400 mg q24h	4 days with adequate source control
Suggested Definitive Guidelines
Organism	Preferred Therapy	Alternative Therapy (Depending on Allergies and Susceptibilities)
Enterobacter spp. (AmpC-producing organism	Cefepime	Meropenem, colistin, tigecycline, trimethoprim/sulfamethoxazole, gentamicin, amikacin Consider combination therapy for extensively drug-resistant Acinetobacter
Suggested Duration of Antimicrobial Therapy Based on Indication
Diagnosis	Duration of Therapy	Key References
Complicated intra-abdominal infection, community-acquired (appendicitis, cholecystitis, diverticulitis)	4 to 7 days after adequate source control	Infectious Diseases Society of America Guidelines: http://www.idsociety.org/uploadedFiles/IDSA/GuidelinesPatient_Care/PDF_Library/Intraabdominal%20Infectin.pdf Other resources: http://www.nejm.org/doi/pdf/10.1056/NEJMoa1411162