Is there a reason to continue antibiotics (abx) in a patient with bloody diarrhea and colitis, who had an initial elevated white blood cell (WBC) count that normalized by day 3, and negative stool studies for pathogens?

Discontinue Antibiotics Immediately

In a patient with bloody diarrhea and colitis whose WBC has normalized by day 3 and has negative stool studies, antibiotics should be discontinued immediately unless there is a specific indication for continued therapy unrelated to the colitis. 1

Rationale for Antibiotic Discontinuation

The clinical scenario described does not support continued antibiotic therapy for several key reasons:

• Normalized inflammatory markers: The WBC count normalized by day 3, indicating resolution of the systemic inflammatory response. Guidelines for intra-abdominal infections specify that antimicrobial therapy should be continued only until resolution of clinical signs of infection, including normalization of temperature, WBC count, and return of gastrointestinal function. 1

• Negative stool studies: With no identified pathogen, there is no microbiologic target for antibiotic therapy. Empirical antibiotic therapy without a confirmed bacterial pathogen increases the risk of complications, including Clostridioides difficile infection (CDI). 1

• Risk of antibiotic-associated complications: Continued antibiotic use is significantly associated with increased risk of CDI recurrence and can perpetuate antibiotic-associated colitis. 1 Virtually all antibiotics, particularly cephalosporins, ampicillin, amoxicillin, and clindamycin, can cause antibiotic-associated hemorrhagic colitis. 2, 3

Clinical Assessment Before Stopping Antibiotics

Before discontinuing antibiotics, verify the following:

• Clinical improvement: Stool frequency should be decreasing or stool consistency improving, with no new signs of severe colitis developing. 1

• Absence of severe colitis markers: Confirm no fever >38.5°C, hemodynamic stability, no signs of peritonitis, no ileus, and no elevated serum lactate. 1, 4

• Rule out CDI: Although stool studies were negative, if CDI testing was not specifically performed or if clinical suspicion remains high (especially if the patient was on antibiotics prior to admission), consider CDI-specific testing. The WBC of 18 on admission meets criteria for severe CDI (WBC ≥15,000 cells/mL). 4, 5

Important Caveats and Pitfalls

Common pitfall: Continuing antibiotics "just to be safe" when inflammatory markers have normalized and no pathogen is identified. This practice increases morbidity through antibiotic-associated complications without improving outcomes. 1

Critical consideration: If the colitis was actually CDI that was missed on initial testing (false negative), stopping antibiotics could paradoxically help if the antibiotics were the inciting agent. However, if CDI is strongly suspected clinically despite negative testing, empirical CDI-directed therapy with oral vancomycin 125 mg four times daily should be considered. 4, 5

Antimotility agents: Ensure antiperistaltic agents and opiates are avoided, as these can worsen outcomes in colitis. 1

When to Consider Continued Antibiotics

Antibiotics should only be continued if:

• Persistent clinical signs of infection: Ongoing fever, rising WBC, worsening abdominal pain, or hemodynamic instability despite 5-7 days of therapy warrant diagnostic re-evaluation with CT imaging rather than empirical continuation of antibiotics. 1

• Documented bacterial pathogen requiring treatment: If subsequent cultures identify a specific pathogen requiring antibiotic therapy, treatment should be narrowed to the most specific agent. 1

• Unrelated infection requiring treatment: If antibiotics are needed for a separate infection (e.g., pneumonia, urinary tract infection), select agents with lower risk of causing CDI, such as parenteral aminoglycosides, sulfonamides, macrolides, or tetracycline/tigecycline. 1

Monitoring After Antibiotic Discontinuation

After stopping antibiotics, monitor for:

• Symptom recurrence: Increasing stool frequency, worsening bloody diarrhea, or development of fever should prompt re-evaluation for CDI or other infectious etiologies. 1, 4

• Signs of treatment failure: Abdominal pain, distension, or constipation developing after initial improvement may indicate complications such as toxic megacolon or ileus. 1