Oral Antibiotic Reduces Risk of C. Diff Infection in Stem Cell Transplant Recipients but Raises Risk of Other Infection

Feb. 20, 2024
While C. diff infections went down in those who took the antibiotic, gram-negative bacteremia cases went up

An oral antibiotic, vancomycin, helps reduce patients’ risk of C. diff infection but may also increase their risk of gram-negative bacteremia, according to new research from Fox Chase Cancer Center.

C. diff infection threatens patients who “undergo stem cell treatment as part of their treatment for blood cancers,” who are at a higher risk for such infections than the general population. C. diff (Clostridioides difficile) is an “overgrowth of bacteria in the gastrointestinal tract” and is a “significant source of increased morbidity and mortality” in these patients.

Lead author Alexander Vartanov, MD, sought to better understand how taking vancomycin preventively can help lessen risk of C. diff infection. To that effect, researchers “looked at infection rates for 441 patients who received hematopoietic (blood-related) stem cell transplants,” splitting the participants up into two groups – a control group who was not given vancomycin and an experimental group that was.

Analysis of the research confirmed that “taking oral vancomycin prophylactically does reduce the C. diff infection rate in stem cell transplant recipients.” The experimental group had a 7% infection rate compared to 13% in the control group.

An unforeseen side effect of vancomycin seems to be an increased rate of gram-negative bacteremia, which is a serious (but often treatable and curable) bacterial infection that can lead to “sepsis, septic shock, and even death” in its most severe outcomes. The rate of gram-negative bacteremia was higher in the group that took vancomycin (21.8%) compared to the control group (13%).

Informed by the results of the research, Fox Chase’s practice now is to “screen all patients undergoing transplant and only administer the prophylactic antibiotic to those who screen positive or have a history of C. diff.”

Fox Chase’s website has the news.