Antibiotic Treatment for Immunosuppressed Patients with Diarrhea

Introduction to Antibiotic Choice

The European Society for Medical Oncology (ESMO) recommends empirical treatment with a fluoroquinolone, specifically ciprofloxacin, as the first-line antibiotic choice for immunosuppressed patients with diarrhea and a negative gastrointestinal film array 1, 2

For complicated diarrhea, fluoroquinolone therapy should be initiated immediately as empirical treatment, with ciprofloxacin being specifically recommended in the ESMO guidelines for complicated cases requiring hospitalization 1, 2
The American College of Physicians and other guideline societies support the use of broad-spectrum antibiotics covering gram-negative organisms, gram-positive organisms, and anaerobes for neutropenic enterocolitis, with reasonable initial choices including monotherapy with piperacillin-tazobactam or imipenem-cilastatin, or combination therapy with cefepime or ceftazidime plus metronidazole 1, 2, 5

Azithromycin has emerged as an important alternative to fluoroquinolones, particularly given rising fluoroquinolone resistance rates, and is now the drug of choice for Campylobacter infections 3, 4

For Salmonella, continue ciprofloxacin; if bacteremic, use ceftriaxone plus ciprofloxacin combination 3, 4
For Shigella, ciprofloxacin or fluoroquinolone is preferred, with azithromycin as an effective alternative 3, 4
For Campylobacter, switch to azithromycin due to fluoroquinolone resistance 3, 4, 6

Immunocompromised patients require IV fluid resuscitation with a rate exceeding ongoing losses, as well as octreotide and complete blood count and electrolyte monitoring 1, 2, 5
Serial abdominal examinations are necessary to detect complications such as perforation, toxic megacolon, and ileus 1, 2, 5