What is the cause of diarrhea in a patient receiving Rocephin (Ceftriaxone) and Daptomycin intravenously for septic arthritis following knee replacement, with negative Clostridioides difficile (C. diff) testing, while taking Vancomycin prophylactically?

From the Guidelines

The patient's diarrhea is likely antibiotic-associated diarrhea (AAD) caused by the broad-spectrum antibiotics (rocephin and daptomycin) disrupting normal gut flora, and I recommend starting probiotics such as Lactobacillus or Saccharomyces boulardii to manage the symptoms. Since C. difficile testing is negative, as per the study 1, the focus should be on managing the AAD. The patient should maintain adequate hydration and consider a BRAT diet (bananas, rice, applesauce, toast) temporarily.

The prophylactic oral vancomycin should be continued as prescribed to prevent C. difficile infection, which is a risk with IV antibiotics for septic arthritis, as mentioned in the study 1. If diarrhea worsens or persists beyond 48-72 hours despite these measures, the antibiotic regimen may need reevaluation. The underlying mechanism involves disruption of intestinal microbiota by antibiotics, allowing overgrowth of pathogenic bacteria or yeast. Approximately 5-30% of patients on antibiotics develop AAD, but most cases resolve with supportive care and completion of the necessary antibiotic course for the septic arthritis.

Some key points to consider in managing the patient's diarrhea include:

• Discontinuing unnecessary antibiotics, as suggested in the study 1, to reduce the risk of AAD
• Using probiotics to restore the normal gut flora, as recommended in the example answer
• Maintaining adequate hydration and considering a BRAT diet to manage symptoms
• Continuing prophylactic oral vancomycin to prevent C. difficile infection, as mentioned in the study 1
• Monitoring the patient's condition and reevaluating the antibiotic regimen if diarrhea worsens or persists, as per the study 1

It is essential to prioritize the patient's morbidity, mortality, and quality of life when managing their diarrhea, and the recommended approach should be based on the most recent and highest-quality evidence available, such as the study 1.

From the FDA Drug Label

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including vancomycin hydrochloride for injection, and may range in severity from mild diarrhea to fatal colitis. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued.

The patient is taking vancomycin prophylactically and reports diarrhea, but is negative for C-diff. Vancomycin is not the likely cause of the diarrhea in this case, as the patient has tested negative for C-diff. However, the possibility of CDAD cannot be completely ruled out, as it can occur even after the administration of antibacterial agents has been stopped.

• The patient's diarrhea should be further investigated to determine the cause.
• Monitoring for signs and symptoms of CDAD is necessary, and discontinuation of unnecessary antibiotics should be considered. 2

From the Research

Patient's Condition

The patient is receiving Rocephin and Daptomycin for septic arthritis (IV) following knee replacement and reports diarrhea, with a negative test for C-diff, while taking vancomycin prophylactically.

• The patient's symptoms and treatment are consistent with septic arthritis, a condition that requires prompt diagnosis and treatment to prevent permanent morbidity and mortality 3, 4.
• The use of vancomycin prophylactically may be related to the patient's diarrhea, as vancomycin is commonly used to treat Clostridioides difficile (C-diff) infections 5, 6.

Septic Arthritis Treatment

The treatment of septic arthritis typically involves empiric antibiotic therapy, with the choice of antibiotic depending on the suspected causative pathogen.

• Staphylococcus aureus is the most common pathogen isolated in septic arthritis, but other bacteria, viruses, fungi, and mycobacterium can also cause the disease 3.
• The duration of antibiotic therapy can range from two to six weeks, depending on the specific infection and the patient's response to treatment 3.

C-diff Infection

Although the patient's test for C-diff is negative, it is possible that the patient may still be at risk for C-diff infection, particularly given their recent history of diarrhea and use of vancomycin prophylactically.

• C-diff infections can cause extraintestinal manifestations, including septic arthritis, particularly in immunocompromised patients 5, 6.
• The patient's negative test for C-diff does not rule out the possibility of a C-diff infection, as the test may not always be sensitive enough to detect the infection 5, 6.

Sepsis Management

The patient's treatment for septic arthritis is consistent with current evidence-based practices for sepsis management.

• Early recognition and treatment of sepsis are critical to improving mortality and morbidity 7.
• The use of empiric antibiotic therapy, as well as supportive care such as fluids and vasopressors, are important components of sepsis management 7.