Novel therapies for severe Clostridium difficile colitis

Polyethylene glycol intestinal lavage in addition to usual antibiotic treatment for severe Clostridium difficile colitis: a randomised controlled pilot study

INTRODUCTION

Clostridium difficile infections (CDI) are common, costly and potentially life threatening. Most CDI will respond to antibiotic therapy, but 3%-10% of all patients with CDI will progress to a severe, life-threatening course. Complete removal of the large bowel is indicated for severe CDI. However, the 30-day mortality following surgical intervention for severe CDI ranges from 20% to 70%. A less invasive approach using surgical faecal diversion and direct colonic lavage with polyethylene glycol (PEG) and vancomycin has demonstrated a relative mortality reduction of approximately 50%. As an alternative to these operative approaches, we propose to treat patients with bedside intestinal lavage with PEG and vancomycin instillation via nasojejunal tube, in addition to usual antibiotic management. Preliminary data collected by our research group are encouraging.

METHODS AND ANALYSIS

We will conduct a 1-year, single-centre, pilot randomised controlled trial to study this new treatment strategy for patients with severe CDI and additional risk factors for fulminant or complicated infection. After informed consent, patients with severe-complicated CDI without immediate indication for surgery will be randomised to either usual antibiotic treatment or usual antibiotic treatment with the addition of 8 L of PEG lavage via nasojejunal tube. This pilot trial will evaluate our eligibility and enrolment rate, protocol compliance and adverse event rates and provide further data to inform a more robust sample size calculation and protocol modifications for a definitive multicentre trial design. Based on historical data, we anticipate enrolling approximately 24 patients during the 1-year pilot study period.As a pilot study, data will be reported in aggregate. Between-group differences will be assessed in a blinded fashion for evidence of harm, and to further refine our sample size calculation.

ETHICS AND DISSEMINATION

This study protocol has been reviewed and approved by our local institutional review board. Results of the pilot trial and subsequent main trial will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT02466698; Pre-results.

Impact of preoperative screening for rectal colonization with fluoroquinolone-resistant enteric bacteria on the incidence of sepsis following transrectal ultrasound guided prostate biopsy

With the universal adoption of antibiotic prophylaxis prior to prostate biopsy, the current risk of post-biopsy infection (including sepsis) is <2%. Preoperative prophylactic antibiotic regimens can vary, and although fluoroquinolones have emerged as the standard of care, there is no universally agreed upon preoperative antibiotic regimen. Recently, an increase in the proportion of postoperative infections caused by fluoroquinolone-resistant Escherichia coli (as well as other Enterobacteriaceae) has led to the exploration of simple, practical, and cost-effective methods to minimize this postoperative infection risk. We performed a prospective, nonrandomized, controlled study of preoperative rectal cultures to screen for rectal colonization with fluoroquinolone-resistant bacteria using ciprofloxacin-supplemented MacConkey agar culture media. To evaluate the feasibility and practicality of this test, one provider used the results of rectal swab cultures collected during the preoperative outpatient evaluation to adjust each patient's preoperative antibiotic prophylaxis when fluoroquinolone-resistant enteric bacteria were detected, whereas two other providers continued usual preoperative care and empiric antimicrobial prophylaxis. Rectal colonization with fluoroquinolone-resistant bacteria was detected in 19/152 (12.5%) of patients. In our intention-to-treat analysis (N=268), the rate of post-biopsy sepsis was 3.6% lower in the group that was screened for rectal colonization with fluoroquinolone-resistant bacteria prior to transrectal prostate biopsy. The observed risk reduction in the rectal screening group trended toward, but did not achieve, statistical significance. We suggest that preoperative screening for rectal colonization with fluoroquinolone-resistant enteric bacteria may be a useful step toward mitigating post-prostate biopsy sepsis.

Rifaximin Improves Clostridium difficile Toxin A-Induced Toxicity in Caco-2 Cells by the PXR-Dependent TLR4/MyD88/NF-κB Pathway

BACKGROUND

Clostridium difficile infections (CDIs) caused by Clostridium difficile toxin A (TcdA) lead to severe ulceration, inflammation and bleeding of the colon, and are difficult to treat.

AIM

The study aimed to evaluate the effect of rifaximin on TcdA-induced apoptosis in intestinal epithelial cells and investigate the role of PXR in its mechanism of action.

METHODS

Caco-2 cells were incubated with TcdA and treated with rifaximin (0.1-10 μM) with or without ketoconazole (10 μM). The transepithelial electrical resistance (TEER) and viability of the treated cells was determined. Also, the expression of zona occludens-1 (ZO-1), toll-like receptor 4 (TLR4), Bcl-2-associated X protein (Bax), transforming growth factor-β-activated kinase-1 (TAK1), myeloid differentiation factor 88 (MyD88), and nuclear factor-kappaB (NF-κB) was determined.

RESULTS

Rifaximin treatment (0.1, 1.0, and 10 μM) caused a significant and concentration-dependent increase in the TEER of Caco-2 cells (360, 480, and 680% vs. TcdA treatment) 24 h after the treatment and improved their viability (61, 79, and 105%). Treatment also concentration-dependently decreased the expression of Bax protein (-29, -65, and -77%) and increased the expression of ZO-1 (25, 54, and 87%) and occludin (71, 114, and 262%) versus TcdA treatment. The expression of TLR4 (-33, -50, and -75%), MyD88 (-29, -60, and -81%) and TAK1 (-37, -63, and -79%) were also reduced with rifaximin versus TcdA treatment. Ketoconazole treatment inhibited these effects.

CONCLUSION

Rifaximin improved TcdA-induced toxicity in Caco-2 cells by the PXR-dependent TLR4/MyD88/NF-κB pathway mechanism, and may be useful in the treatment of CDIs.