Therapy of relapsing Clostridium difficile-associated diarrhea and colitis with the combination of vancomycin and rifampin

Repurposing the Antiamoebic Drug Diiodohydroxyquinoline for Treatment of Clostridioides difficile Infections

Clostridioides difficile, the leading cause of nosocomial infections, is an urgent health threat worldwide. The increased incidence and severity of disease, the high recurrence rates, and the dearth of effective anticlostridial drugs have created an urgent need for new therapeutic agents. In an effort to discover new drugs for the treatment of Clostridioides difficile infections (CDIs), we investigated a panel of FDA-approved antiparasitic drugs against C. difficile and identified diiodohydroxyquinoline (DIHQ), an FDA-approved oral antiamoebic drug. DIHQ exhibited potent activity against 39 C. difficile isolates, inhibiting growth of 50% and 90% of these isolates at concentrations of 0.5 μg/ml and 2 μg/ml, respectively. In a time-kill assay, DIHQ was superior to vancomycin and metronidazole, reducing a high bacterial inoculum by 3 log₁₀ within 6 h. Furthermore, DIHQ reacted synergistically with vancomycin and metronidazole against C. difficile in vitro. Moreover, at subinhibitory concentrations, DIHQ was superior to vancomycin and metronidazole in inhibiting two key virulence factors of C. difficile, toxin production and spore formation. Additionally, DIHQ did not inhibit the growth of key species that compose the host intestinal microbiota, such as Bacteroides, Bifidobacterium, and Lactobacillus spp. Collectively, our results indicate that DIHQ is a promising anticlostridial drug that warrants further investigation as a new therapeutic for CDIs.

The microbiome and disorders of the central nervous system

Alterations of the gut microbiota have been associated with stress-related disorders including depression and anxiety and irritable bowel syndrome (IBS). More recently, researchers have started investigating the implication of perturbation of the microbiota composition in neurodevelopmental disorders including autism spectrum disorders and Attention-Deficit Hypersensitivity Disorder (ADHD). In this review we will discuss how the microbiota is established and its functions in maintaining health. We also summarize both pre and post-natal factors that shape the developing neonatal microbiota and how they may impact on health outcomes with relevance to disorders of the central nervous system. Finally, we discuss potential therapeutic approaches based on the manipulation of the gut bacterial composition.

Recurrent Clostridium difficile infection: From colonization to cure

Clostridium difficile infection (CDI) is increasingly prevalent, dangerous and challenging to prevent and manage. Despite intense national and international attention the incidence of primary and of recurrent CDI (PCDI and RCDI, respectively) have risen rapidly throughout the past decade. Of major concern is the increase in cases of RCDI resulting in substantial morbidity, morality and economic burden. RCDI management remains challenging as there is no uniformly effective therapy, no firm consensus on optimal treatment, and reliable data regarding RCDI-specific treatment options is scant. Novel therapeutic strategies are critically needed to rapidly, accurately, and effectively identify and treat patients with, or at-risk for, RCDI. In this review we consider the factors implicated in the epidemiology, pathogenesis and clinical presentation of RCDI, evaluate current management options for RCDI and explore novel and emerging therapies.

Clostridium difficile infection: a review of the literature

Clostridium difficile is a Gram-positive, strictly anaerobic, spore-forming bacterium. It is the most common cause of antibiotic-associated diarrhea in hospitals and other healthcare facilities and is of significant concern because of the increasing morbidity and mortality rates as well as increased health care costs. Spectrum of presentation of Clostridium difficile infection ranges from mild, self-limiting diarrhea, to serious diarrhea, pseudomembranous colitis and life-threatening fulminant colitis, which may result in death. Prompt identification of patients with symptomatic Clostridium difficile infection is essential as the majority of patients respond quickly to antimicrobial therapy. Prevention is best accomplished by implementation of infection-control measures and by judicious use of antimicrobial agents.

European Society of Clinical Microbiology and Infectious Diseases: update of the treatment guidance document for Clostridium difficile infection

In 2009 the first European Society of Clinical Microbiology and Infection (ESCMID) treatment guidance document for Clostridium difficile infection (CDI) was published. The guideline has been applied widely in clinical practice. In this document an update and review on the comparative effectiveness of the currently available treatment modalities of CDI is given, thereby providing evidence-based recommendations on this issue. A computerized literature search was carried out to investigate randomized and non-randomized trials investigating the effect of an intervention on the clinical outcome of CDI. The Grades of Recommendation Assessment, Development and Evaluation (GRADE) system was used to grade the strength of our recommendations and the quality of the evidence. The ESCMID and an international team of experts from 11 European countries supported the process. To improve clinical guidance in the treatment of CDI, recommendations are specified for various patient groups, e.g. initial non-severe disease, severe CDI, first recurrence or risk for recurrent disease, multiple recurrences and treatment of CDI when oral administration is not possible. Treatment options that are reviewed include: antibiotics, toxin-binding resins and polymers, immunotherapy, probiotics, and faecal or bacterial intestinal transplantation. Except for very mild CDI that is clearly induced by antibiotic usage antibiotic treatment is advised. The main antibiotics that are recommended are metronidazole, vancomycin and fidaxomicin. Faecal transplantation is strongly recommended for multiple recurrent CDI. In case of perforation of the colon and/or systemic inflammation and deteriorating clinical condition despite antibiotic therapy, total abdominal colectomy or diverting loop ileostomy combined with colonic lavage is recommended.

Microbiota dynamics in patients treated with fecal microbiota transplantation for recurrent Clostridium difficile infection

Clostridium difficile causes antibiotic-associated diarrhea and pseudomembraneous colitis and is responsible for a large and increasing fraction of hospital-acquired infections. Fecal microbiota transplantation (FMT) is an alternate treatment option for recurrent C. difficile infection (RCDI) refractory to antibiotic therapy. It has recently been discussed favorably in the clinical and scientific communities and is receiving increasing public attention. However, short- and long-term health consequences of FMT remain a concern, as the effects of the transplanted microbiota on the patient remain unknown. To shed light on microbial events associated with RCDI and treatment by FMT, we performed fecal microbiota analysis by 16S rRNA gene amplicon pyrosequencing of 14 pairs of healthy donors and RCDI patients treated successfully by FMT. Post-FMT patient and healthy donor samples collected up to one year after FMT were studied longitudinally, including one post-FMT patient with antibiotic-associated relapse three months after FMT. This analysis allowed us not only to confirm prior reports that RCDI is associated with reduced diversity and compositional changes in the fecal microbiota, but also to characterize previously undocumented post-FMT microbiota dynamics. Members of the Streptococcaceae, Enterococcaceae, or Enterobacteriaceae were significantly increased and putative butyrate producers, such as Lachnospiraceae and Ruminococcaceae were significantly reduced in samples from RCDI patients before FMT as compared to post-FMT patient and healthy donor samples. RCDI patient samples showed more case-specific variations than post-FMT patient and healthy donor samples. However, none of the bacterial groups were invariably associated with RCDI or successful treatment by FMT. Overall microbiota compositions in post-FMT patients, specifically abundances of the above-mentioned Firmicutes, continued to change for at least 16 weeks after FMT, suggesting that full microbiota recovery from RCDI may take much longer than expected based on the disappearance of diarrheal symptoms immediately after FMT.

Treatment of recurrent Clostridium difficile infection: a systematic review

BACKGROUND

Clostridium difficile infection (CDI) recurs in nearly one-third of patients who develop an initial infection. Recurrent CDI (RCDI) is associated with considerable morbidity, mortality, and cost. Treatment for RCDI has not been not well examined.

METHODS

A systematic review.

RESULTS

Sixty-four articles were identified evaluating eight different treatment approaches: metronidazole, vancomycin, fidaxomicin, nitazoxanide, rifampin, immunoglobulins, probiotics, and fecal bacteriotherapy. The meta-analysis found vancomycin to have a similar efficacy to metronidazole, although studies used varying doses and durations of therapy. Fidaxomicin was slightly more efficacious than vancomycin, though the number of studies was small. Good evidence for probiotics was limited. Fecal bacteriotherapy was found to be highly efficacious in a single randomized trial.

CONCLUSION

Metronidazole and vancomycin have good evidence for use in RCDI but heterogeneity in treatment duration and dose precludes robust conclusions. Fidaxomicin may have a role in treatment, but evidence is limited to subgroup analyses. Fecal bacteriotherapy was the most efficacious. Saccharomyces boulardii may have a role as adjunctive treatment.

Guidelines for diagnosis, treatment, and prevention of Clostridium difficile infections

Clostridium difficile infection (CDI) is a leading cause of hospital-associated gastrointestinal illness and places a high burden on our health-care system. Patients with CDI typically have extended lengths-of-stay in hospitals, and CDI is a frequent cause of large hospital outbreaks of disease. This guideline provides recommendations for the diagnosis and management of patients with CDI as well as for the prevention and control of outbreaks while supplementing previously published guidelines. New molecular diagnostic stool tests will likely replace current enzyme immunoassay tests. We suggest treatment of patients be stratified depending on whether they have mild-to-moderate, severe, or complicated disease. Therapy with metronidazole remains the choice for mild-to-moderate disease but may not be adequate for patients with severe or complicated disease. We propose a classification of disease severity to guide therapy that is useful for clinicians. We review current treatment options for patients with recurrent CDI and recommendations for the control and prevention of outbreaks of CDI.

Rifaximin in Combination with Metronidazole and Oral Vancomycin for the Treatment of an Initial Episode of Clostridium difficile–Associated Diarrhea: Case Report and Literature Review

Purpose

Example of successful use of rifaximin in the treatment of an apparent Clostridium difficile infection refractory to vancomycin and metronidazole with literature review.

Case Summary

A 69-year-old Caucasian female developed C. difficile infectious diarrhea, confirmed by enzyme immunoassay (EIA) test. Following diagnosis, the patient was initiated on a treatment regimen of intravenous (IV) metronidazole and oral vancomycin. The patient sought additional medical treatment 3 days after initiating this treatment regimen. She presented with continued symptoms of diarrhea, bloating, anorexia, weakness, and leukocytosis nonresponsive to metronidazole and vancomycin. After a total of 7 days of treatment with metronidazole and vancomycin, the patient remained symptomatic with loose stools occurring approximately every 2 hours. Oral rifaximin 400 mg 3 times a day was added to the regimen, after which the patient's symptoms improved rapidly.

Conclusion

A patient with presumed C. difficile–associated diarrhea refractory to metronidazole and vancomycin was successfully treated after the addition of oral rifaximin 400 mg 3 times a day. Based on current literature and this case, rifaximin should not replace metronidazole or vancomycin as primary therapy for presumed or diagnosed C. difficile but should be retained as a useful alternative, especially in light of limited alternatives.

New advances in the treatment of Clostridium difficile infection (CDI)

Clostridium difficile infections (CDI) have increased in frequency throughout the world. In addition to an increase in frequency, recent CDI epidemics have been linked to a hypervirulent C. difficile strain resulting in greater severity of disease. Although most mild to moderate cases of CDI continue to respond to metronidazole or vancomycin, refractory and recurrent cases of CDI may require alternative therapies. This review provides a brief overview of CDI and summarizes studies involving alternative antibiotics, toxin binders, probiotics, and immunological therapies that can be considered for treatment of acute and recurrent CDI in severe and refractory situations.

Immunization with Bacillus spores expressing toxin A peptide repeats protects against infection with Clostridium difficile strains producing toxins A and B

Clostridium difficile is a leading cause of nosocomial infection in the developed world. Two toxins, A and B, produced by most strains of C. difficile are implicated as virulence factors, yet only recently has the requirement of these for infection been investigated by genetic manipulation. Current vaccine strategies are focused mostly on parenteral delivery of toxoids. In this work, we have used bacterial spores (Bacillus subtilis) as a delivery vehicle to evaluate the carboxy-terminal repeat domains of toxins A and B as protective antigens. Our findings are important and show that oral immunization of the repeat domain of toxin A is sufficient to confer protection in a hamster model of infection designed to closely mimic the human course of infection. Importantly, neutralizing antibodies to the toxin A repeat domain were shown to be cross-reactive with the analogous domain of toxin B and, being of high avidity, provided protection against challenge with a C. difficile strain producing toxins A and B (A(+)B(+)). Thus, although many strains produce both toxins, antibodies to only toxin A can mediate protection. Animals vaccinated with recombinant spores were fully able to survive reinfection, a property that is particularly important for a disease with which patients are prone to relapse. We show that mucosal immunization, not parenteral delivery, is required to generate secretory IgA and that production of these neutralizing polymeric antibodies correlates with protection. This work demonstrates that an effective vaccine against C. difficile can be designed around two attributes, mucosal delivery and the repeat domain of toxin A.

Alternative therapies for Clostridium difficile infections

Clostridium difficile infection is a serious condition responsible for significant morbidity and mortality, especially in patients being treated with antimicrobials. Increasing frequency of the infection and hypervirulent C. difficile strains have resulted in more severe disease as well as therapeutic failures with traditional treatment (metronidazole and vancomycin). To review the studies assessing nontraditional therapies for the prevention and treatment of primary or recurrent C. difficile infection, we conducted a literature search of the PubMed-MEDLINE databases (1984-2010). Of the 98 studies identified, 21 met our inclusion criteria. Five clinical trials and one retrospective medical record review evaluated probiotic or prebiotic formulations for the prevention of C. difficile infection. Only one of these studies, which included Lactobacillus casei and L. bulgaricus in the probiotic formulation, showed efficacy. Ten clinical trials evaluated treatment of an initial episode of C. difficile infection (primary treatment) with the anti-microbials fidaxomicin, fusidic acid, rifampin, teicoplanin, and nitazoxanide, as well as the toxin-binding polymer, tolevamer. Only nitazoxanide and teicoplanin demonstrated noninferiority when compared with vancomycin or metronidazole. Four prospective studies and one retrospective study evaluated treatment of relapsing C. difficile infection. Prebiotic formulations for the prevention and treatment of recurrent C. difficile infection have not proved to be clinically warranted. Nitazoxanide, teicoplanin, and fidaxomicin may be considered as alternatives to traditional treatment; however, clinical experience is limited with these agents for this indication. Bacteriotherapy with fecal instillation has demonstrated high clinical cure rates in case studies and in a retrospective study; however, to our knowledge, randomized clinical trials are lacking for this therapeutic approach. As C. difficile infection rates continue to increase and hypervirulent strains continue to emerge, it is important for future clinical studies to assess alternative therapies.

Therapeutic Success of Rifaximin for Clostridium difficile Infection Refractory to Metronidazole and Vancomycin

We report the case of a 46-year-old white male with confirmed Clostridium difficile infection for >4 weeks after fluoroquinolone therapy. The patient received two courses of metronidazole 500 mg three times daily (t.i.d.) during which time diarrhea resolved; however, symptoms recurred 14-15 days after treatment termination. He received a 2-week course of vancomycin 125 mg four times daily, with symptoms recurring 10 days after treatment conclusion. The patient then received a pulsed tapering schedule of vancomycin with adjunctive Saccharomyces boulardii. Diarrhea recurred 12 days after treatment completion. He received rifaximin 400 mg t.i.d. while hospitalized for diarrhea-associated complications. Symptoms resolved within 24 h. The patient received a 4-week regimen of rifaximin 400 mg orally t.i.d. after discharge. No further episodes of diarrhea were reported within 6 months after treatment termination. The present case supports the potential benefit of rifaximin for the treatment of recurrent Clostridium difficile infection.

Risk Factors for Treatment Failure and Recurrence after Metronidazole Treatment for Clostridium difficile-associated Diarrhea

BACKGROUND/AIMS

The incidence of treatment failure or recurrence of Clostridium difficile-associated diarrhea (CDAD) following metronidazole treatment has increased recently. We studied the treatment failure, recurrence rate, and risk factors predictive of treatment failure and recurrence after metronidazole treatment for CDAD.

METHODS

We retrospectively identified consecutive patients who were admitted and treated for CDAD at a single tertiary institution in Korea over a recent 10-year period (i.e., 1998-2008).

RESULTS

Metronidazole was administered as the initial treatment to 111 of 117 patients (94.9%) with CDAD. Fourteen patients (12.6%) had no clinical response to the metronidazole treatment, and in 13 patients (13.4%) CDAD recurred after successful metronidazole treatment. Diabetes mellitus (p=0.014) and sepsis (p=0.002) were independent risk factors for metronidazole treatment failure. Patients who had received surgery within 1 month before CDAD developed were more likely to experience a recurrence after metronidazole treatment (p=0.032). Vancomycin exhibited a higher response rate after treatment failure, and metronidazole showed a reasonable response rate in the treatment of recurrence. Treatment failure and recurrence rates increased with time after metronidazole treatment for CDAD over the 10-year study period.

CONCLUSIONS

Our data suggest that diabetes mellitus and sepsis are independent risk factors for metronidazole treatment failure, and that operation history within 1 month of development of CDAD is a predictor of a recurrence after metronidazole treatment.

European Society of Clinical Microbiology and Infectious Diseases (ESCMID): treatment guidance document for Clostridium difficile infection (CDI)

Clostridium difficile infection (CDI) is a potentially fatal illness with an increasing incidence worldwide. Despite extensive ongoing research into CDI treatment, management of CDI still poses important problems, such as a high propensity to relapse and refractoriness to treatment, especially when there is an ileus and oral drugs cannot be administered. This guideline evaluates the available literature, discusses criteria for disease severity and provides recommendations for CDI treatment, indicating level of evidence and strength of recommendation.

Clostridium difficile and the disease it causes

Clostridium difficile is a spore-forming, toxin-producing, anaerobic bacterium abundant in soils and water. Frequent and early colonization of the human intestinal flora is common and often asymptomatic. Antimicrobials given commonly disrupt the intestinal microflora and through proliferation in colon and production of toxin A and B it precipitates C. difficile infection (CDI). The enterocytic detachment and bowel inflammation provoke C. difficile-associated diarrhoea (CDAD) sometimes developing into severe pseudomembranous colitis (PMC) and paralytic ileus. Infection is acquired from an endogenous source or from spores in the environment, most easily facilitated during hospital stay. In the elderly, comorbidity, hospitalization and antimicrobial treatment present as major risk factors and the slow recolonization of the normal flora likely responsible for single or multiple recurrences of CDI (25-50%) post therapy. The key procedure for diagnosis is toxin detection from stool specimens and sometimes in combination with culture to increase sensitivity. In mild cases stopping the offending antimicrobial will lead to resolution (25%) but standard therapy still consist of either oral metronidazole or vancomycin. Alternative agents are presently being developed and fidaxomicin, as well as nitrothiazolide are promising. Furthermore, host factors like low antitoxin A levels in serum relates to increased risk of recurrence and small numbers of patients have received immunoglobulin with good results. An immunogenic toxoid vaccine has been developed and human colostrum rich in specific secretory Ig A also support the future use of immunotherapy. Today we experience a tenfold increase of CDI incidence in the western world and both epidemics and therapeutic failure of metronidazole is contributing to morbidity and mortality. The current epidemic of the C. difficile strain NAP1/027 emerging in 2002 in Canada and the USA has now spread to most parts of Europe and virulence factors like high toxin production and sporulation challenge the therapeutic situation and cause great concern among infection control workers. Excessive use of modern fluoroquinolones is thought to play an important role in facilitating this epidemic since NAP1/027 was shown to have acquired moxifloxacin resistance compared to historical strains of the same genotype. Both the current epidemic like this and other local outbreaks from resistant or virulent strains warrant culture to be routinely performed enabling susceptibility testing and typing of the pathogen. Genotyping is most commonly done today by pulse-field gel electrophoresis (PFGE) or PCR ribotyping but multilocus variable-number tandem-repeat analysis (MLVA) seems promising. Epidemiological surveillance using all these tools will help us to better understand the global spread of C. difficile.

Recurrent Clostridium difficile infection: causality and therapeutic approaches

Recurrent diarrhoea after successful treatment of the primary episode is a common complication of Clostridium difficile infection (CDI) and may be increasing in frequency. Evidence suggests that persistent alterations in the indigenous bowel flora and failure to mount an effective antibody response to C. difficile toxins are the main mechanisms whereby recurrent CDIs occur. Treatment of the first recurrence with the same agent used for the treatment of the primary episode is reasonable, but a different approach is needed for patients with multiple CDI recurrences. Prolonged, repeated courses of metronidazole are discouraged, but a practical first option in these patients is to use tapered-dose oral vancomycin followed by a pulsed-dose regimen. Other potential options include probiotic approaches, restoration of the normal flora, immunological approaches, toxin-binding approaches, and serial therapy with vancomycin followed by rifaximin. Randomised studies including a sufficient numbers of patients have not yet been conducted for the treatment of recurrent CDI and are needed to help guide the formulation of effective recommendations.

Clostridium difficile colitis

Clostridium difficile is the most common cause of infectious diarrhea in hospitalized patients. Its effects are mediated by C difficile toxins A and B. Recent outbreaks of severe colitis have been associated with a new strain of the bacterium that produces large amounts of the toxins. Although oral metronidazole and oral vancomycin can be used to treat C difficile-associated disease, intraluminal vancomycin is preferable for more severe C difficile colitis. Early surgical intervention can improve outcomes with fulminant colitis, although overall mortality remains high.

The management of Clostridium difficile infection

INTRODUCTION/BACKGROUND

Clostridium difficile is the commonest cause of nosocomial diarrhoea. The epidemiology and clinical phenotype of the disease has dramatically changed with the global emergence of a virulent strain of C. difficile.

SOURCE

This review was compiled using data from individual studies and review articles identified from PubMed. The retrieved articles were also examined for additional references.

AREAS OF AGREEMENT

Appropriate and timely infection control measures are required to control C. difficile infection (CDI) in the hospital environment, and either oral metronidazole or vancomycin remains the mainstay of treatment depending on the severity of infection.

AREAS OF CONTROVERSY

The optimal method for diagnosing CDI remains unclear, as does the best therapeutic strategy for the management of multiple relapses. GROWING POINTS/AREAS TIMELY FOR DEVELOPING RESEARCH: Studies of new antimicrobial agents with activity against C. difficile are required to improve the management of multiply relapsing disease. The use of novel therapeutic approaches that do not require antimicrobials requires urgent research, including the use of immunological or vaccine-based regimen, bacteriotherapy or C. difficile-specific bacteriophages.

New antimicrobial agents for patients with Clostridium difficile infections

Current drug treatment of Clostridium difficile infection (CDI) focuses on metronidazole and vancomycin. Early studies showed equivalence, but more recent reports indicate that oral vancomycin is preferred for serious CDI. Recent work has demonstrated a need for new drugs due to challenges with the NAP-1 strain, which appears to cause more refractory disease that is more likely to relapse. These two distinctive facets of treatment are the most challenging. This review discusses new agents in development: antibiotics, probiotics, immune response products, and agents to bind C. difficile toxins. None are likely to be more effective than oral vancomycin for acute infection. However, several may be as effective, without causing relapse or promoting unnecessary antibiotic use for multiple conditions. The greatest promise is with agents used to interrupt relapses. In this category the leading new agents appear to be antibiotics (rifaximin, nitazoxanide, difimicin, ramoplanin), toxin-binding agents (tolevamer), probiotics (Saccharomyces -boulardii and Lactobacillus ramosus), and immune agents (toxoid vaccine and hyperimmune globulin). The drugs that appear most promising based on recent trials are rifaximin, tolevamer, and difimicin, which appear promising for reducing relapses.

Clostridium difficile infection: emerging concepts and treatments

Clostridium difficile infection has become one of the most common causes of diarrhea in patients frequenting hospitals, skilled nursing facilities, and physicians' offices. Although the pathogenesis and clinical description were well elucidated three decades ago, cure during the initial episode now occurs in fewer than two thirds of patients exhibiting clinical illness. The past decade has brought a new strain with more toxin. Frequent relapses in elderly patients are now the norm rather than a rarity. This review is intended to update clinicians regarding diagnosis, infection control, and treatment, including treatment of the difficult-to-treat patient with multiple relapses of C. difficile infection.

Rifamycin antibiotics for treatment of Clostridium difficile-associated diarrhea

OBJECTIVE

To review the existing data on use of the rifamycin class of antibiotics as therapy for Clostridium difficile-associated diarrhea (CDAD).

DATA SOURCES

A literature search was performed using PubMed (1996-January 2008), abstracts from the International Conference on Antimicrobial Agents and Chemotherapy (September 2007), the Infectious Diseases Society of America (October 2007), Salix Pharmaceuticals Web site (January 2008), ActivBiotics Web site (January 2008), Google Scholar, and searches of selected bibliographies using the terms rifamycin, ansamycins, rifampin, rifabutin, rifampicin, rifaximin, rifalazil, Clostridium difficile, C. difficile, and CDAD.

STUDY SELECTION AND DATA EXTRACTION

In vivo and in vitro studies investigating the use of rifamycins for CDAD were selected, along with all clinical trials using rifamycins in patients with CDAD.

DATA SYNTHESIS

Nine studies totaling 890 isolates were identified that investigated the in vitro susceptibility of rifampin (6 studies), rifaximin (3 studies), and rifalazil (2 studies). Rifamycins consistently displayed potent activity against tested strains, although strains with decreased susceptibility have been identified. Six published clinical studies involving 81 patients have investigated the use of rifamycins for the treatment of CDAD. These have generally been small studies, although initial positive clinical results have been reported on the use of rifamycins for recurrent CDAD.

CONCLUSIONS

Preliminary data support the use of rifamycins for treatment of CDAD. With the increased incidence and severity of CDAD, further investigation into this drug class as a treatment regimen for CDAD is warranted.

Treatment of Clostridium difficile infection

Recent outbreaks of Clostridium difficile infection (CDI) in North America have been due to a more virulent, possibly more resistant strain that causes more-severe disease, making prompt recognition of cases and optimal management of infection essential for a successful therapeutic outcome. Treatment algorithms are presented to help guide the management of patients with CDI. Metronidazole has been recommended as initial therapy since the late 1990s and continues to be the first choice for all but seriously ill patients and those with complicated or fulminant infections or multiple recurrences of CDI, for whom vancomycin is recommended. Other options for recurrent CDI, such as probiotics and currently available anion-exchange resins, have limited efficacy and are potentially harmful. Intravenous immunoglobulin may benefit patients with refractory, recurrent, or severe disease, but no controlled data are available. Two antimicrobials available in the United States for other indications, nitazoxanide and rifaximin, have been used successfully for CDI treatment but, like metronidazole, lack United States Food and Drug Administration approval for this indication. Experimental treatments currently in clinical development include a toxin-binding polymer, tolevamer; 2 poorly absorbed antimicrobials, OPT-80 (formerly known as Difimicin) and ramoplanin; monoclonal antibodies; and a C. difficile vaccine.

Diarrheal diseases in the elderly

Diarrhea in the elderly population is one disease that needs special attention in treatment and management, especially in acute- and long-term care residents, because of their multiple comorbidities, immunosenescence, frailty, and poor nutritional status. Close follow-up to ensure adequate hydration and electrolyte replacement and infection control measures to contain outbreaks should be emphasized to caregivers and nursing staff in acute- and long-term care facilities. Although C difficile colitis causes significant morbidity and mortality in this population, judicious use of antibiotics is important to decrease the incidence and recurrence of the disease. When the diarrhea is chronic and all stool testings and serologies have been performed, the patient may benefit from endoscopy and colonoscopy for biopsy. Attentive and vigilant nursing staff is crucial in the timely diagnosis and treatment of diarrheal diseases to improve quality of life and reduce mortality.

Treatment strategies for recurrent and refractory Clostridium difficile-associated diarrhea

Clostridium difficile, the most common nosocomial infection of the GI tract, has become a bigger threat with the emergence of a hypervirulent strain. C. difficile-associated diarrhea (CDAD) is usually a consequence of antibiotic therapy or chemotherapy, but sporadic cases occur, and an increase in severe sporadic cases is of great concern. Epidemics of CDAD with high morbidity and mortality have been documented in the USA, Canada and Europe, making accurate diagnosis, effective therapy and strategies for prevention more important than ever. Treatment of refractory and recurrent CDAD remain therapeutic challenges. Improved treatments are needed; several new drugs are currently in trials.

Clostridium difficile-associated disease: changing epidemiology and implications for management

Clostridium difficile-associated disease (CDAD) is increasingly being reported in many regions throughout the world. The reasons for this are unknown, are likely to be multifactorial, and are the subject of several current investigations. In addition to the upsurge in frequency of CDAD, an increased rate of relapse/recurrence, disease severity and refractoriness to traditional treatment have also been noted. Moreover, severe disease has been reported in non-traditional hosts (e.g. younger age, seemingly healthy, non-institutionalised individuals residing in the community, and some without apparent antimicrobial exposure). A previously uncommon and more virulent strain of C. difficile has been reported at the centre of multiple transcontinental outbreaks. The appearance of this more virulent strain, in association with certain environmental and antimicrobial exposure factors, may be combining to create the 'perfect storm'. It is human nature to be reactive; however, the successful control of C. difficile will require healthcare systems (including administrators, and leadership within several departments such as environmental services, infection control, infectious diseases, gastroenterology, surgery, microbiology and nursing), clinicians, long-term care and rehabilitation facilities, and patients themselves to be proactive in a collaborative effort. Guidelines for the management of CDAD were last published over a decade ago, with the next iteration due in the fall (autumn) of 2007. Several newer therapies are under investigation but it is unclear whether they will be superior to current treatment options.

Identification, Optimal Management, and Infection Control Measures for Clostridium difficile–Associated Disease in Long-Term Care

Residents of long-term care facilities are at an increased risk of exposure to Clostridium difficile and become more susceptible to infection after receiving antimicrobial therapy. An increasing number and more severe cases of C. difficile-associated disease (CDAD) have been reported over the last few years and have been linked to the emergence of a new, more virulent strain of C. difficile. These serious cases of disease have also been associated with a more atypical clinical presentation and have prompted the need for an improved means of early recognition and identification performed by the nursing staff. This article reviews the pathogenesis and risk factors for CDAD, changing epidemiology of CDAD, and characteristics of the newly identified strain. Also reviewed are the role of nursing in the identification of patients with CDAD; optimal management of CDAD; infection control strategies; and education of health care professionals, residents, and visitors in the long-term care setting.

Clinical aspects of rifampicin-associated pseudomembranous colitis

Pseudomembranous colitis (PMC) is known to develop after antibiotic administration, but antituberculosis agents are rarely associated with this disorder. We report 6 cases of PMC after rifampicin administration; the clinical manifestations, laboratory findings, imaging findings, and clinical course are described. The median age of patients was 68 years (range, 54 to 82 y). All patients were diagnosed with active pulmonary tuberculosis by sputum smear and culture, and 2 suffered from type 2 diabetes mellitus. The average interval between initiation of antituberculosis therapy and the onset of diarrhea was 19.8 days. The anatomic distribution of PMC included the rectum and sigmoid colon in 5 cases and up to the hepatic flexure in 1 case. All patients were cured with medical treatment, which include discontinuation of rifampicin and oral metronidazole and vancomycin. PMC recurred in 1 patient after retreatment with rifampicin. Our findings suggest that patients who are treated with antituberculosis agents, who develop acute diarrhea during or after therapy, should be evaluated for PMC.

Past, present, and future therapies for Clostridium difficile-associated disease

OBJECTIVE

To describe and examine the past, present, and potential future treatment options for Clostridium difficile-associated disease (CDAD).

DATA SOURCES

A PubMed search, restricted to English-language articles concerning CDAD, was conducted (1965-October 2006) using the key words Clostridium difficile, diarrhea, vancomycin, metronidazole, immunoglobulin, and recurrence. Additional references were located through review of the bibliographies of cited articles and by visiting www.clinicaltrials.gov.

STUDY SELECTION AND DATA EXTRACTION

Articles related to the clinical manifestations, diagnosis, and treatment of CDAD, as well as articles addressing current issues related to CDAD, were included.

DATA SYNTHESIS

There have been many investigations into CDAD because of the recent increased incidence and morbidity and mortality of the disease. Various studies examining the changing epidemiology and pathogenicity of C. difficile, as well as new therapies for CDAD with agents such as tolevamer and nitazoxanide, are ongoing. In addition, researchers are investigating probiotics and vaccines to evaluate their effectiveness in preventing CDAD and/or preventing recurrences of CDAD. Studies assessing therapies for refractory CDAD are lacking, although case reports have been published citing treatment strategies using vancomycin enemas, intravenous metronidazole, colestipol and cholestyramine, fecal enemas, bowel irrigation, and immunoglobulin. Furthermore, judicious use of antimicrobials, contact precautions, and adequate environmental cleaning are being evaluated in healthcare institutions as methods for controlling and preventing the spread of C. difficile.

CONCLUSIONS

Oral metronidazole is the drug of choice for an initial CDAD episode. Oral vancomycin is an option for patients who cannot take or fail treatment with oral metronidazole. Clinical trials are necessary to define the therapy for initial CDAD that is most appropriate and produces lower recurrence rates compared with oral metronidazole or vancomycin treatment. Moreover, appropriate treatment for patients with multiple recurrences of or refractory CDAD needs to be determined. More studies are also needed assessing prevention of recurrences of CDAD.

Prospective, randomized inpatient study of oral metronidazole versus oral metronidazole and rifampin for treatment of primary episode of Clostridium difficile-associated diarrhea

BACKGROUND

To date, no randomized trial to address the use of adjunctive rifampin in addition to metronidazole for the treatment of Clostridium difficile-associated diarrhea has been reported. Rifampin has excellent in vitro activity against C. difficile and penetrates into cellular materials where the organisms may persist.

METHODS

This was a prospective, randomized, single-blinded study of 39 patients that compared therapy with metronidazole alone versus therapy with metronidazole and rifampin for 10 days to treat laboratory-confirmed primary episode C. difficile-associated diarrhea. Twenty patients were randomly assigned to the metronidazole group, and 19 were randomly assigned to the metronidazole and rifampin group. Data were analyzed by intention-to-treat analysis using the 2-tailed Kaplan-Meier method and the log-rank test.

RESULTS

Adjunctive rifampin treatment for 10 days, compared with treatment with metronidazole alone for 10 days, was associated with a similar median time to symptom improvement (9.0 days vs. 6.5 days; P=.74), a similar median time to first relapse (26 days vs. 16 days; P=.23), a similar proportion of patients with relapse by study day 40 (42% vs. 38%; P=1.0), and a similar proportion of patients experiencing nonfatal adverse events (37% vs. 40%; P=.55). There were a significantly higher number of deaths in the metronidazole and rifampin group, compared with the metronidazole group (6 of 19 patients vs. 1 of 20 patients; P=.04), but there were fewer laboratory-confirmed relapses by study day 40 (2 vs. 4; P=.66).

CONCLUSIONS

We conclude that there is no role for routine rifampin as an adjunct to treatment with metronidazole for hospitalized patients with C. difficile-associated diarrhea. The cure rates for both treatment groups remain unacceptably low, and better treatments are urgently needed.

An update on diagnosis, treatment, and prevention of Clostridium difficile-associated disease

Clostridium difficile is an important cause of nosocomial morbidity and mortality and is implicated in recent epidemics. Data support the treatment of colitis with oral metronidazole in a dose of 1.0 to 1.5 g/d, with oral vancomycin as a second-line agent, not because its efficacy is questioned but because of environmental concerns. Nitazoxanide and other drugs are currently under intense study as alternatives. Treatment of asymptomatic patients is not recommended. Current management strategies appear to be increasingly ineffective, especially for patients who experience multiple recurrences. Biotherapy and vaccination are currently being explored as treatment options for patients who have recurrent disease. Greater attention should be paid to hospital infection control policies and restriction of broad-spectrum antibiotics.

Clostridium difficile–Associated Disease: An Emerging Threat to Patient Safety: Insights from the Society of Infectious Diseases Pharmacists

A formerly infrequently isolated strain of Clostridium difficile known as BI/NAP1 has resulted in geographically diverse outbreaks of C. difficile-associated disease. Such rapid dissemination and distribution of an outbreak strain of C. difficile are unprecedented, with many regions across North America, as well as several countries in Europe, being affected, all in such a short period of time. Also of note is that nontraditional hosts (e.g., otherwise healthy, noninstitutionalized persons residing in the community, some without antimicrobial exposure) have been reported to have severe disease. Data suggest that certain virulence characteristics may be responsible for more severe clinical presentations and poor outcomes. These factors (e.g., hypertoxin production, hypersporulation, antimicrobial resistance) possessed by a previously uncommon strain of C. difficile, in conjunction with particular host and environmental factors, may have precipitated the now widespread establishment of this pathogen. Antimicrobial intervention has traditionally been a mainstay of combating C. difficile-associated disease. Efforts to combat BI/NAP1 should include good antimicrobial stewardship in addition to effective infection control and environmental intervention.

Antimicrobial resistance of Clostridium difficile isolates in a tertiary medical center, Israel

The antimicrobial susceptibilities of 49 Clostridium difficile isolates obtained from patients with C. difficile-associated diarrhea to metronidazole, vancomycin, rifampicin, fusidic acid, doxycycline, and linezolid were determined by the disc diffusion and Etest (Biodisk, Solna, Sweden). Random amplification of polymorphic DNA-PCR amplification assay was performed for studying clonality of isolates. Resistance to metronidazole was found in 2% (1/49 isolates; MIC > or = 256 microg/mL) of isolates and resistance to linezolid in 2% (1/49 isolates; MIC = 24 microg/mL). One isolate showed combined resistance to fusidic acid (by disc diffusion test) and rifampicin (MIC > or = 32 microg/mL). All isolates were sensitive to doxycycline and vancomycin. Molecular typing revealed an absence of clonality among the resistant isolates, whereas the sensitive isolates were monoclonal. Resistance of C. difficile to metronidazole and other antimicrobials including linezolid exists in our institution. This finding should promote exploration of this problem in Israel and clarify the impact of resistance on outcome.

Treatment of Clostridium difficile-associated disease: old therapies and new strategies

Clostridium difficile-associated disease (CDAD) causes substantial morbidity and mortality. The pathogenesis is multifactorial, involving altered bowel flora, production of toxins, and impaired host immunity, often in a nosocomial setting. Current guidelines recommend treatment with metronidazole; vancomycin is a second-line agent because of its potential effect on the hospital environment. We present the data that led to these recommendations and explore other therapeutic options, including antimicrobials, antibody to toxin A, probiotics, and vaccines. Treatment of CDAD has increasingly been associated with failure and recurrence. Recurrent disease may reflect relapse of infection due to the original infecting organism or infection by a new strain. Poor antibody responses to C difficile toxins have a permissive role in recurrent infection. Hospital infection control and pertinent use of antibiotics can limit the spread of CDAD. A vaccine directed against C difficile toxin may eventually offer a solution to the CDAD problem.

Clostridium difficile: an update

Clostridium difficile causes a spectrum of diarrheal illness with the potential for major medical consequences. Although most cases respond quickly to treatment, C. difficile colitis may be severe and life threatening. Recurrent disease represents a particularly challenging problem.

Alternative treatments for Clostridium difficile disease: what really works?

Vancomycin and metronidazole have been used for treating Clostridium difficile-associated disease (CDAD) for the past 25 years, but approximately 20 % of patients develop recurrent disease. The increasing incidence of nosocomial outbreaks, cases of recurrent CDAD and other complications (toxic megacolon, ileus, sepsis) has fuelled the search for different types of treatments. As the understanding of the pathogenesis of this disease has matured, newer treatment strategies that take advantage of these mechanisms have been developed. This review will describe such treatments and examine the evidence for each strategy.

Rifalazil treats and prevents relapse of clostridium difficile-associated diarrhea in hamsters

Although vancomycin and metronidazole effectively treat Clostridium difficile-associated diarrhea and colitis (CDAD), their use is associated with a high incidence of relapsing C. difficile infection. Rifalazil is a new benzoxazinorifamycin that possesses activity against Mycobacterium tuberculosis and gram-positive bacteria. Here we compared rifalazil and vancomycin for effectiveness in preventing or treating clindamycin-induced cecitis in a hamster model of CDAD. Golden Syrian hamsters were injected subcutaneously with clindamycin phosphate (10 mg/kg), followed 24 h later by C. difficile gavage. Hamsters received by gavage for 5 days vehicle, vancomycin (50 mg/kg), or rifalazil (20 mg/kg) either simultaneously with (prophylactic protocol) or 24 h after C. difficile administration (treatment protocol). While all vehicle-administered animals became moribund within 48 h of C. difficile administration, no rifalazil- or vancomycin-treated animals in either protocol showed signs of morbidity after 7 days. Ceca of rifalazil-treated animals showed absence of epithelial cell damage, significantly reduced congestion and edema, and less, but not statistically significantly less, neutrophil infiltration compared to those of vehicle-treated animals. In contrast, vancomycin-treated animals demonstrated severe epithelial cell damage and mildly reduced congestion and edema. Moreover, hamsters relapsed and tested C. difficile toxin positive (by enzyme-linked immunosorbent assay) 10 to 15 days after discontinuation of vancomycin treatment. None of the rifalazil-treated hamsters showed signs of disease or presence of toxins in their feces 30 days after discontinuation of treatment. Our results indicate that once daily rifalazil may be superior to vancomycin for curative treatment of CDAD.

Clostridium difficile-associated diarrhea in adults

Clostridium difficile is the most important cause of nosocomial diarrhea in adults. Illness may range from mild watery diarrhea to life-threatening colitis. An antecedent disruption of the normal colonic flora followed by exposure to a toxigenic strain of C. difficile are necessary first steps in the pathogenesis of disease. Diagnosis is based primarily on the detection of C. difficile toxin A or toxin B. First-line treatment is with oral metronidazole therapy. Treatment with oral vancomycin therapy should be reserved for patients who have contraindications or intolerance to metronidazole or who fail to respond to first-line therapy.

Successful treatment with rifampin for fulminant antibiotics-associated colitis in a patient with non-Hodgkin's lymphoma

A 74-year-old man was admitted to the hospital because of chemotherapy for relapsed non-Hodgkin's lymphoma (NHL). The patient became febrile and experienced diarrhea after chemotherapy. Although ceftazidime and amikacin sulfate were administered as empiric therapy, diarrhea was continued. After several days, stool cytotoxin assay for clostridium difficile (C. difficile) was positive and he was diagnosed as having antibiotics-associated colitis (AAC). Although antibiotics were discontinued and both oral vancomycin and metronidazole were administrated, disease was not improved. To rule out the presence of an additional cause of diarrhea, colon fibroscopic examination was performed. It revealed multiple deep ulcerative lesions at right side colon, surface erosive and minute erosive lesions in all continuous colon. Pseudomembranes were not seen. These findings are compatible with AAC without pseudomembranes. There are no reports that the rifampin is effective on refractory AAC. However, we administered oral rifampin for the current patient. The reasons are 1) conventional antibiotics were not effective, 2) rifampin has excellent in vitro activity against C. difficile, and 3) the efficacy of rifampin on relapsing colitis due to C. difficile is established. After administration of rifampin, fever alleviated and diarrhea was improved. Because AAC may result in significant mortality, patients with refractory or fulminant AAC should be treated with oral rifampin from outset.

Recurrent Clostridium difficile colitis: case series involving 18 patients treated with donor stool administered via a nasogastric tube

Clostridium difficile-associated diarrhea and colitis have emerged as major complications associated with use of systemic antimicrobials. In this study, the medical records for 18 subjects who received donor stool by nasogastric tube for recurrent C. difficile infection during a 9-year period at a single institution were retrospectively reviewed. During the period between the initial diagnosis of C. difficile colitis and the stool treatments, the 18 subjects received a total of 64 courses of antimicrobials (range, 2-7 courses; median, 3 courses). During the 90 days after receipt of treatment with stool, 2 patients died of unrelated illnesses. One of the 16 survivors experienced a single recurrence of C. difficile colitis during 90-day follow-up. No adverse effects associated with stool treatment were observed. Patients with recurrent C. difficile colitis may benefit from the introduction of stool from healthy donors via a nasogastric tube.

Treatment of Clostridium difficile-associated diarrhea

OBJECTIVE

To review the literature related to the treatment and infection control of Clostridium difficile-associated diarrhea (CDAD).

DATA SOURCES

A MEDLINE search (1966-August 2001) of the English literature was conducted.

DATA SYNTHESIS

C. difficile is a leading cause of antibiotic-related diarrhea. The clinical spectrum extends from simple diarrhea to fulminant colitis. Cessation of antibiotic therapy alone is sufficient for mild cases; however, the majority of cases require oral metronidazole as the drug of choice. Vancomycin orally is reserved for patients who have failed to respond to metronidazole, are pregnant, or are severely ill. There is an important role for infection control interventions.

CONCLUSIONS

CDAD is a common infection. Appropriate antibiotic treatment and infection control policies can prevent the spread and reduce the morbidity associated with this disease.