Blog | Wednesday, July 2, 2014

2 adventures in the microbiome

First, there’s a really interesting paper in Clinical Infectious Diseases on a novel treatment for recurrent Clostridium difficile infection. In this retrospective, uncontrolled experience, 25 patients with recurrent C. difficile infection (mean number of relapses=4, median days of illness=135) were treated with either metronidazole or oral vancomycin, along with kefir (5 oz., 3 times daily). The antibiotics were given for 2 weeks at a standard dose (i.e., vancomycin 125 mg every 6 hours). In the next 2 week period, it was given at 3 times standard dose once every 72 hours (i.e., 375 mg), followed by 2 weeks of 2 times standard dose every 72 hours, then 2 weeks of standard dose every 72 hours. This strategy is known as staggered and tapered antibiotic withdrawal (STAW). The kefir was continued for 2 months after the antibiotic was discontinued.

I had to learn about kefir as I knew very little about it. It’s essentially milk in which the lactose has been fermented by bacteria. It contains 10 strains of bacteria at a concentration of 7-10 billion CFU/cup. Thus, it’s a big gun probiotic, and comes in several different flavors and forms (liquid, frozen, yogurt, cheese). You can find it in most grocery stores.

The end result was that 84% of the patients treated with STAW + kefir were diarrhea-free at 9 months. Again, this was an uncontrolled study, but nonetheless quite intriguing. I will certainly try this regimen in patients with recurrent C. difficile as an option for patients who either don’t want to have a fecal transplant or would like to try this before resorting to transplant. I also wonder whether we should be serving kefir to hospitalized, nonimmunosuppressed patients as a prophylactic strategy for C. difficile. This weekend, I’ll sample some of the products myself.

Second, there’s an intriguing case report that was just published in Clinical Microbiology and Infection. The authors describe a 60 year old man status-post renal transplant who had 8 episodes of transplant pyelonephritis with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. Due to graft failure, transplant nephrectomy was performed. Despite that, he remained persistently rectally colonized with the infecting strain, and was therefore removed from the waiting list for re-transplant. He then underwent fecal transplant via a nasoduodenal tube.

One week later, rectal culture was still positive for the ESBL E. coli. However, beginning 2 weeks post-transplant, his rectal culture was negative and remained negative during 12 weeks of follow-up. Due to the fecal transplant, he is now back on the transplant waiting list. Over a year ago, I blogged about a study where fecal transplantation was used to successfully eradicate vancomycin-resistant enterococcus colonization in mice, so biologic plausibility clearly exists for multidrug resistant organism decolonization. This indication could potentially greatly increase the demand for a procedure that is limited on the supply side (i.e., too few providers willing to perform the procedure). But it’s another great example of the importance of the microbiome and the implications of being able to therapeutically alter it.

Michael B. Edmond, MD, FACP, is a hospital epidemiologist in Richmond, Va., with a focus on understanding why infections occur in the hospital and ways to prevent these infections, and sees patients in the inpatient and outpatient settings. This post originally appeared at the blog Controversies in Hospital Infection Prevention.