What is the role of cefixime (Cefixime) in treating bacillary diarrhea?

Role of Cefixime in Bacillary Diarrhea

Cefixime is NOT recommended as first-line therapy for bacillary diarrhea, but serves as an acceptable second-line oral option for enteric fever (typhoid) at 8 mg/kg/day in children or 400 mg daily in adults for 7-14 days, particularly when azithromycin or ceftriaxone are unavailable or not tolerated. 1

First-Line Treatment Recommendations

For bacillary diarrhea, empiric antibiotics are generally not indicated for most patients, as acute gastroenteritis typically resolves without specific therapy. 2 However, when antibiotics are warranted based on specific clinical scenarios, the preferred agents are:

• Azithromycin (1000 mg single dose or 500 mg daily for 3 days in adults; 20 mg/kg/day for 7 days in children with enteric fever) is the first-line choice, showing 94% cure rates and lower relapse risk (OR 0.09) compared to cephalosporins. 1, 2
• Fluoroquinolones (ciprofloxacin 500-750 mg orally) are alternatives in adults, but over 70% of S. typhi isolates show resistance in many regions, particularly South Asia. 1, 2

When to Consider Cefixime

Cefixime may be used in the following situations:

• Enteric fever (typhoid/paratyphoid) when azithromycin is not available or tolerated, at 8 mg/kg/day as a single daily dose in children or 400 mg daily in adults for 7-14 days. 1
• Shigellosis as an alternative agent, though clinical data show limitations with shorter courses. 3

Evidence for Cefixime in Bacillary Diarrhea

Shigellosis Treatment Data

A randomized controlled trial comparing 2-day versus 5-day cefixime therapy (8 mg/kg/day) for Shigella sonnei in children demonstrated that while both regimens achieved similar clinical cure rates by Day 3, the 2-day course had significantly higher bacteriologic failure rates (55% vs 14%, P < 0.02) and similar clinical relapse rates (24% vs 20%). 3 This indicates that 5-day courses are necessary for adequate bacteriologic eradication, even though symptoms may resolve earlier.

Enteric Fever Context

For enteric fever specifically, cefixime at 8 mg/kg/day represents an appropriate oral option according to the American Academy of Pediatrics, particularly in children over 28 days old. 1 However, it remains inferior to azithromycin, which shows lower clinical failure rates (OR 0.48) and shorter hospital stays. 1

Clinical Scenarios Requiring Antibiotics

Antibiotics should be considered for bacillary diarrhea in these specific situations:

• Infants <3 months with suspected bacterial etiology (use third-generation cephalosporin). 2
• Immunocompromised patients with severe illness and bloody diarrhea. 2
• Patients with fever, abdominal pain, bloody diarrhea suggesting Shigella (bacillary dysentery). 2
• Recent international travelers with body temperatures ≥38.5°C and/or signs of sepsis. 2

Critical Pitfalls to Avoid

• Never use antibiotics for STEC O157 infections or other Shiga toxin 2-producing organisms due to increased risk of hemolytic uremic syndrome. 2
• Do not use cefixime empirically from South Asia without susceptibility testing due to high resistance rates. 1
• Avoid 2-day courses of cefixime for shigellosis, as bacteriologic failure rates exceed 50%. 3
• Always obtain blood cultures before starting antibiotics when enteric fever is suspected. 1

Dosing and Duration

When cefixime is used:

• Children: 8 mg/kg/day as a single daily dose for 7-14 days. 1
• Adults: 400 mg orally once daily for 7-14 days. 1
• Administer in divided doses (200 mg twice daily) if gastrointestinal side effects occur, as once-daily 400 mg dosing shows higher incidence of diarrhea. 4

Adverse Effects

Diarrhea and stool changes are the most common adverse effects (16-24% of patients), usually mild to moderate, transient, and occurring in the first few days of treatment. 5, 6 These effects are generally less problematic with twice-daily dosing compared to once-daily administration. 4

Monitoring and Follow-Up

• Expected fever clearance within 4-5 days of appropriate therapy for enteric fever. 1
• Transfer to oral regimen once clinical improvement occurs and temperature has been normal for 24 hours. 1
• Modify or discontinue antimicrobial therapy when a specific pathogen is identified and susceptibility results are available. 2