New treatment and prevention strategies are necessary to treat Clostridium difficile, the most common cause of nosocomial infectious diarrhea. A combination of approaches, ranging from environmental cleaning strategies and contact precautions to emerging therapies like antitoxins and fecal transplants, was a major focus at the inaugural ASM Microbe 2016 conference.
Curtis Donskey, MD, of the Louis Stokes Cleveland VA Medical Center, discussed effective C difficile prevention strategies, such as environmental cleaning and contact precautions.1 Dr Donskey suggested that these strategies could be even more effective with regular monitoring of cleaning, feedback to housekeepers, use of automated devices, educational interventions regarding contact precautions, daily disinfection of high-touch surfaces, and patient encouragement to bathe and wash their hands. He also emphasized the need for more education, since failure of these strategies can often be attributed to poor implementation.
A 2014 study by Landelle and colleagues2 found that despite contact precautions, 24% of health care workers still had C difficile spores on their hands due to high-risk contacts such as bedpans, and at least 1 instance of contact without gloves. Other studies suggest that incorrect removal of personal protective equipment also plays a role in the failure of prevention strategies. Additionally, Dr Donskey pointed out that patients shed C difficile spores before and after diagnosis.
Antibiotic use is a major risk factor for C difficile infection (CDI), suggesting that a major facet of CDI prevention involves antimicrobial stewardship, or appropriate antibiotic therapy.
Two presentations at ASM Microbe 2016 discussed the impact of antimicrobial stewardship programs on CDI. Katherine Shea, PharmD, of Cardinal Health, Dublin, Ohio, presented a retrospective study showing that intervention reduced moxifloxacin use by 14.5 days during the targeted education phase, and by 24.5 days during the fluoroquinolone restriction phase.3 This reduction correlated with CDI-rate reductions of 3.43 days per 10,000 patients during the education phase and 2.2 days per 10,000 patients during the restriction phase.
Stephanie Kuhn, PharmD, of the Wesley Medical Center, Wichita, Kansans, reported that in 2014, the Center eliminated postoperative antibiotic prophylaxis and removed antibiotics from postoperative order sets in response to research showing the ineffectiveness of postoperative prophylaxis. However, this change in policy had no significant effect on CDI rates at the Wesley Medical Center, either overall or among surgical patients.4
Probiotics and increased attention to asymptomatic carriers have also been suggested as CDI prevention strategies. However, guidelines do not recommend probiotics at present, due to limited data, mixed results, and uncertain effects. Likewise, screening and isolation of asymptomatic carriers is not recommended. However, Dr Donskey noted a recent study by Longtin and colleagues, published in JAMA Internal Medicine in June 2016, demonstrating that detection and isolation of asymptomatic carriers reduced expected cases of hospital-acquired CDI by 62%.5
Emerging Treatment Approaches for CDI
Several presentations at ASM Microbe 2016 focused on emerging treatment approaches for CDI. Richard J. Vickers, PhD, of Summit Therapeutics, Abingdon, UK, presented additional efficacy and safety data from the phase 2 CoDIFy trial, which concluded that treatment with the narrow-spectrum antibiotic ridinilazole conferred a sustained clinical response rate of 66.7%, compared with 42.4% for vancomycin (difference 21.1%, 90% confidence interval [CI] 3.1, 39.1), and a recurrence rate of 14.3% versus 34.8% for vancomycin. Ridinilazole was favored over vancomycin even in groups at higher risk for recurrent CDI (rCDI). 6-7