Preventative antibiotics could prevent Clostridium difficile infection among stem cell transplant patients

The researchers will present their findings at this week's 58th Annual American Society of Hematology Meeting and Exposition in San Diego.

Clostridium difficile infection, more commonly known as C. diff, causes diarrhea and can lead to severe inflammation of the bowel. These infections can be not only extremely uncomfortable, but can lead to other severe medical complications. Even with a course of antibiotics, the infection can lead to longer hospital stays and increased treatment cost. A study published last year in the American Journal of Gastroenterology found the average cost of C. diff ranges from $8,911 to $30,049 per patient.

Oral vancomycin is a standard antibiotic used to treat C. diff, and researchers at the Abramson Cancer Center began giving it to patients on a preventative basis -- twice daily from the day of admission to the day of discharge. Their study focused on patients with blood cancers undergoing an allogeneic stem cell transplant -- in which patients receive stem cells from a healthy donor after high-intensity chemotherapy or radiation. Since these transplants require patients' immune systems to be suppressed so they do not reject their new bone marrow cells, this group of patients is at high risk for life-threatening infections as their new immune systems develop.

The results were significant. Of the 73 patients who took the drug prophylactically, none developed C. diff during their inpatient admission for the stem cell transplant, which lasted an average of 33 days. In a group of patients who did not get the drug in advance, 11 out of 55 (20 percent) developed the infection, which is within the national average of between 20 to 30 percent.

"This is the first study to evaluate this preventative strategy in stem cell transplant recipients, and the results are encouraging," said the study's lead author Alex Ganetsky, PharmD, a clinical pharmacist in the Blood and Marrow Transplantation Program in the Abramson Center Center. "This may become the standard of care at Penn among patients receiving allogeneic stem cell transplants."

Ganetsky says the practice could expand, with acute leukemia patients who are being hospitalized for other types of treatment potentially being the next population to benefit from the prophylactic medication. But the researchers say that given the rising threat of antibiotic resistance across the world, further study will be needed to pinpoint best uses of the drug to avoid overuse.

"What we want to do is maximize the appropriate use of antibiotics," said the study's senior author David Porter, MD, the director of Blood and Marrow Transplantation and Jodi Fisher Horowitz Professor in Leukemia Care Excellence in the Abramson Cancer Center. "With our control group showing a 20 percent infection rate, that means we're giving the antibiotics to a lot of people who would not have otherwise developed C. diff, but given the risks associated with the condition for these patients, our results demonstrate a potential path to protecting more of them during a very vulnerable period in their recovery."

While the treatment has proven effective at preventing C. diff, the study did not show a shortened length of hospitalization among the patients.

"This was a retrospective analysis, so we need to follow up with randomized trials that specifically look at length of stay," Porter said. "Finding such a drop-off in C. diff is enough to push us to continue this line of study."

Porter also says this study shows the benefits of Penn's multidisciplinary approach, and how doctors, pharmacists, and other staff with different perspectives can bring added benefits to patient care.

"Highly trained pharmacists are part of our transplant team, and they're embedded with the unit," Porter said. "From medication to side-effect management, it is natural and critical to work alongside them as part of the transplant process."