Selecting an antibiotic regimen for empiric therapy
- For community acquired infections, the prevalence of enterobacteriaceae with extended spectrum beta-lactamases (ESBL) is more than ten percent or in patients with severe infection, then it would be advisable to include a beta-lactam- beta-lactamase inhibitor (BL-BLI) or a carbapenem in the regimen. If the prevalence is less than ten percent, then third generation cephalosporin may be used. For patients receiving third generation cephalosporins, additional administration of metronidazole would be needed.
- Double anaerobic cover is now recognized as a redundant practice world over. Empiric cover for Enterococcus, methicillin resistant Staphylococcus aureus or Candida is not necessary in patients with community acquired intra abdominal infection.
- For health care associated infections, the empiric regimen would largely be determined by the profile of organisms found in the hospital settings. A reasonable choice would be imipenem or meropenem (depending on the susceptibility pattern in hospital setting). Covering for enterococci may be needed for healthcare associated infections particularly for postoperative patients, immunosuppressed patients or those who have been on antibiotics which select out enterococci such as cephalosporins.
- In health care associated infections, carbapenem resistant gram negative organisms may be present and may need coverage. An intraoperative culture is usually of benefit in patients with healthcare associated infections.
- Empiric coverage for Candida may be needed in immunosuppressed patients, patients with perforated gastric ulcer on acid suppressants, presence of malignancy, recurrent intra-abdominal infection and if the intra-op cultures showing candida. Either an echinocandin or fluconazole can be used.