Treatment of antibiotic-associated Clostridium difficile colitis with oral vancomycin: comparison of two dosage regimens

Review article: the use of biotherapeutic agents in the prevention and treatment of gastrointestinal disease

There is presently a lack of well conducted clinical trials demonstrating any significant benefits of probiotics in humans. With the exception of diarrhoea due to rotavirus infection in children there is little evidence from randomized, double-blind, placebo-controlled studies that bacterial probiotics have a significant beneficial action in preventing diarrhoea of any cause. The yeast Saccharomyces boulardii has been shown to be of benefit in the prevention of antibiotic-associated diarrhoea but not in preventing infection with Clostridium difficile. S. boulardii may also be of benefit in preventing relapse of C. difficile infection. Because of the simplicity of in vitro systems and some animal models, beneficial characteristics of probiotics such as the ability of bacteria to bind to epithelial surfaces are not always transferable to humans. Thus any postulated benefit from consumption of probiotic bacteria should only be accepted as fact after testing in clinical studies. This review outlines our present knowledge of the mode of action of probiotics and presents the data from clinical trials on their use.

Risk factors for early recurrent Clostridium difficile-associated diarrhea

Recurrence is a common sequela of Clostridium difficile-associated diarrhea (CDD) and may increase morbidity, costs, and treatment-related antimicrobial resistance. Because recurrent CDD (RCDD) frequently occurs very soon after an initial episode, our goal was to determine the risk factors for early RCDD (occurring < or = 45 days after the initial episode). We conducted a case-control study, comparing 13 patients with early RCDD (case patients) with 46 patients who had only one CDD episode (control patients) at Centre Hospitalier Angrignon (Québec) during January 1993 through November 1994. Risk factors for early RCDD included a history of chronic renal insufficiency, a white blood cell count of > or = 15 x 10(3)/mm3, and community-acquired diarrhea with the first CDD episode. For seven of eight case patients, C. difficile strains from the first and second CDD episodes were identical, suggesting that relapse is more common than reinfection. These results suggest that treatments should be directed at preventing relapses in patients at high risk for early RCDD.

Clostridium difficile infection

Clostridium difficile infection is associated with broad-spectrum antibiotic therapy and is the most common cause of infectious diarrhea in hospital patients. Pathogenic strains of C. difficile produce two protein exotoxins, toxin A and toxin B, which cause colonic mucosal injury and inflammation. Infection may be asymptomatic, cause mild diarrhea, or result in severe pseudomembranous colitis. Diagnosis depends on the demonstration of C. difficile toxins in the stool. The first step in management is to discontinue the antibiotic that caused diarrhea. If diarrhea and colitis are severe or persistent, oral metronidazole is the treatment of choice. Oral vancomycin is also effective, but it is more expensive than metronidazole and its widespread use may encourage the proliferation of vancomycin-resistant nosocomial bacteria. Diarrhea and colitis usually improve within three days after a patient starts taking metronidazole or vancomycin, but 20% suffer a relapse of diarrhea when these agents are discontinued.

Surgical aspects of Clostridium difficile colitis

BACKGROUND

There has been a marked increase in the number of surgical patients developing Clostridium difficile colitis. The epidemiology, pathogenesis, diagnosis and management of C. difficile infection were reviewed from a surgical perspective.

METHODS

A literature review was carried out based primarily on a Medline search of all English language publications containing the term C. difficile.

RESULTS

The recent dramatic increase in diagnosis of C. difficile infection amongst surgical patients results from heightened awareness of the condition, better methods of diagnosis, more widespread use of antibiotics for treatment and prophylaxis, and the increasing numbers of elderly and immunocompromised patients with malignancy, sepsis, and (multiple) organ failure being cared for within intensive therapy and high-dependency units. In addition to morbidity and mortality, the economic burden of C. difficile infection in terms of delayed discharge and other hospital costs is considerable.

CONCLUSION

Appropriate use of antibiotics, isolation of affected patients and meticulous hygiene measures on the part of staff are vital if the morbidity, mortality and economic consequences of this nosocomial infection are to be minimized.

Clostridium difficile-associated diarrhea and colitis

OBJECTIVES

To review and summarize the status of diagnosis, epidemiology, infection control, and treatment of Clostridium difficile-associated disease (CDAD).

DIAGNOSIS

A case definition of CDAD should include the presence of symptoms (usually diarrhea) and at least one of the following positive tests: endoscopy revealing pseudomembranes, stool cytotoxicity test for toxin B, stool enzyme immunoassay for toxin A or B, or stool culture for C difficile (preferably with confirmation of organism toxicity if a direct stool toxin test is negative or not done). Testing of asymptomatic patients, including those who are asymptomatic after treatment, is not recommended other than for epidemiologic purposes. Lower gastrointestinal endoscopy is the only diagnostic test for pseudomembranous colitis, but it is expensive, invasive, and insensitive (51% to 55%) for the diagnosis of CDAD. Stool culture is the most sensitive laboratory test currently in clinical use, but it is not as specific as the cell cytotoxicity assay.

EPIDEMIOLOGY

C difficile is the most frequently identified cause of nosocomial diarrhea. The majority of C difficile infections are acquired nosocomially, and most patients remain asymptomatic following acquisition. Antimicrobial exposure is the greatest risk factor for patients, especially clindamycin, cephalosporins, and penicillins, although virtually every antimicrobial has been implicated. Cases of CDAD unassociated with prior antimicrobial or antineoplastic use are very rare. Hands of personnel, as well as a variety of environmental sites within institutions, have been found to be contaminated with C difficile, which can persist as spores for many months. Contaminated commodes, bathing tubs, and electronic thermometers have been implicated as sources of C difficile. Symptomatic and asymptomatic infected patients are the major reservoirs and sources for environmental contamination. Both genotypic and phenotypic typing systems for C difficile are available and have enhanced epidemiologic investigation greatly.

INFECTION CONTROL

Successful infection control measures designed to prevent horizontal transmission include the use of gloves in handling body substances and replacement of electronic thermometers with disposable devices. Isolation, cohorting, handwashing, environmental disinfection, and treatment of asymptomatic carriers are recommended practices for which convincing data of efficacy are not available. The most successful control measure directed at reduction in symptomatic disease has been antimicrobial restriction.

TREATMENT

Treatment of symptomatic (but not asymptomatic) patients with metronidazole or vancomycin for 10 days is effective; metronidazole may be preferred to reduce risk of vancomycin resistance among other organisms in hospitals. Recurrence of symptoms occurs in 7% to 20% of patients and is due to both relapse and reinfection. Over 90% of first recurrences can be treated successfully in the same manner as initial cases. Combination treatment with vancomycin plus rifampin or the addition orally of the yeast Saccharomyces boulardii to vancomycin or metronidazole treatment has been shown to prevent subsequent diarrhea in patients with recurrent disease.

Vancomycin

Vancomycin is a nontoxic glycopeptide antibiotic most often used to treat serious gram-positive infections, C. difficile diarrhea/colitis, and endocarditis and hemodialysis shunt prophylaxis. Vancomycin should not be added to drug regimens for gram-positive coverage, and the empiric use of vancomycin should be discouraged to avoid the emergence of VRE. Vancomycin serum levels are no longer necessary or cost effective in most patients because vancomycin is not nephrotoxic.

Clostridium difficile infection: a common clinical problem for the general internist

Considering the current wide use of antimicrobial agents, the general internist is commonly faced with the patient at risk for diarrhea due to C. difficile. The diagnosis should be considered for any patient with diarrhea who has received any type of antibiotic therapy in the preceding 4-6 weeks. Symptoms may range from a minor bout of diarrhea to fulminant and fatal colitis. Diagnosis usually requires demonstration of the toxin in stool; culture of the organism and fiberoptic endoscopy may play an adjunctive role in selected clinical settings. The ultimate goal in the treatment for C. difficile infection is to repopulate the normal colonic flora in the most efficacious manner. Minimally symptomatic patients may respond to discontinuing the offending antimicrobial agent or using nonspecific binding agents. Oral vancomycin continues to be the "gold standard" for specific treatment, while metronidazole therapy is considered the first-line agent for individuals with milder infection. Oral bacitracin shows promise, though large studies are lacking. Patients with multiple relapses of C. difficile diarrhea can be treated with prolonged courses of vancomycin or a combination of vancomycin and rifampin. Intensive care unit patients who are NPO have few therapeutic options besides intravenous administration of metronidazole and oral administration of vancomycin via clamped nasogastric tube. Preventive efforts are directed at cautious use of antibiotics and the use of vinyl gloves when caring for patients with known infection.

Clostridium difficile infection: responses, relapses and re-infections

Clostridium difficile infection is a common and potentially lethal complication of antibiotic usage. Since the aetiology of antibiotic-associated colitis was discovered 14 years ago, two antibiotics in particular, metronidazole and vancomycin, have been used to treat C. difficile infection. Studies comparing the efficacy of these antibiotics are reviewed. It is now apparent that many of the so-called 'relapses' of C. difficile infection following antibiotic treatment are, in fact, re-infections. Such findings have major infection control implications.

Oral vancomycin-induced rash: case report and review of the literature

Disseminated rash and pruritus are described in an 82-year-old woman with chronic renal failure following administration of oral vancomycin hydrochloride 125 mg q6h for the treatment of Clostridium difficile colitis. Renal function was estimated to be 0.27 mL/s based on a serum creatinine of 177 mumol/L. After eight days of therapy, she developed a slightly raised maculopapular rash on her legs and torso, which spread to her abdomen and arms with continued treatment. Vancomycin was discontinued and the patient was treated symptomatically. The rash cleared and did not recur. Rechallenge with vancomycin was not initiated. No other changes in medications or initiations of new medications occurred during the time of treatment with vancomycin. The patient denied any previous immunologically mediated reactions to medications. Maculopapular rash is rare secondary to vancomycin administration, particularly after oral administration. Although clinically significant serum concentrations can be obtained in patients treated with oral vancomycin who have concomitant C. difficile colitis and renal failure, there has not been a clear correlation between these concentrations and any reported adverse sequelae. This case supports the possible occurrence of a true allergic reaction secondary to low-dose oral vancomycin administration.

Vancomycin

Vancomycin is a glycopeptide antibiotic that is active against staphylococci, streptococci, and other gram-positive bacteria. It is the drug of choice for the treatment of infections due to methicillin-resistant staphylococci, Corynebacterium jeikeium, and multiply resistant strains of Streptococcus pneumoniae. Vancomycin is an alternative treatment for serious staphylococcal and streptococcal infections, including endocarditis, when allergy precludes the use of penicillins and cephalosporins. Vancomycin is bactericidal against most strains of staphylococci and nonenterococcal streptococci. Although rare strains of staphylococci and enterococci that are resistant to vancomycin have been reported, bacterial resistance has thus far not emerged as a major clinical problem despite widespread use of vancomycin. When therapy is monitored by periodic determinations of serum concentrations of the drug and rapid infusion rates are avoided, vancomycin is rarely associated with serious toxicity.

The clinical significance of antibiotic-associated pseudomembranous colitis in the 1990s

Antibiotic-associated pseudomembranous colitis is an uncommon but potentially serious adverse reaction, resulting in acute diarrhoea and characterised by colonic pseudomembranes. A direct relationship between the disease, recent antibiotic therapy and proliferation of Clostridium difficile in the colonic lumen was established in the late 1970s. It is thought that antibiotic therapy may alter the enteric flora, enabling C. difficile to proliferate and produce toxins with cytopathic (toxin B or cytotoxin) and hypersecretory (toxin A or enterotoxin) effects on the mucosa. Apart from clindamycin, the first antibiotic recognised to be clearly associated with pseudomembranous colitis, the antimicrobial agents most commonly responsible are cephalosporins and ampicillin (or amoxicillin). However, virtually all antibiotics except parenterally administered aminoglycosides can cause the disease. Vancomycin and metronidazole, 2 drugs used to treat antibiotic-associated pseudomembranous colitis, have also been reported to be responsible for the complication when used parenterally. Pseudomembranous colitis may develop after perioperative prophylactic antibiotic therapy with cephalosporins. Antibiotic-associated pseudomembranous colitis is most frequent in elderly and debilitated patients and in intensive care units. Nosocomial acquisition of C. difficile has been documented. Therefore it has been recommended that enteric isolation precautions should be taken with patients with this disease. The clinical symptoms include watery diarrhoea, abdominal cramping, and frequently fever, leucocytosis and hypoalbuminaemia. Toxic megacolon and acute peritonitis secondary to perforation of the colon are the most serious complications. The pseudomembranes are usually seen during endoscopic procedures, sigmoidoscopy or, if possible, colonoscopy; the most useful microbiological tests for confirmation of the diagnosis include cycloserine cefoxitin fructose agar (CCFA) stool cultures and stool toxin assays on tissues or by immunological techniques. However, cultures and toxin tests may be positive in patients without pseudomembranous colitis or C. difficile-associated diarrhoea. Mild cases may respond to discontinuation of the drug responsible, but therapy with an anticlostridial antibiotic is often necessary: a 10-day course of oral vancomycin, metronidazole or bacitracin should be given. Relapses are seen in 5 to 50% of patients treated. Antibiotic treatment should avoid sporulation leading to other relapses. 'Biotherapy' (lactobacilli, Saccharomyces) has also been proposed.

Therapy for acute infectious diarrhea in children

This article reviews current recommendations of therapy with antidiarrheal compounds and antimicrobial agents for acute infectious diarrhea in children. In most infants and children with acute infectious diarrhea, treatment with antidiarrheal compounds is not indicated. Many of these compounds interfere with identification of enteropathogens in stool specimens, and the antimotility class has an overdose potential. Antimicrobial therapy is given to reduce symptoms and to prevent the spread of infection by decreasing fecal shedding of organisms. Although effective therapy is not available for patients with enteric viruses, Cryptosporidium, and Microsporidium, therapy is useful for children with amebiasis, antimicrobial-associated colitis, cholera, giardiasis, various forms of Escherichia coli diarrhea and Salmonella disease, isosporiasis, shigellosis, and strongyloidiasis. For several other conditions, antimicrobial therapy is of questionable benefit (infection with Campylobacter jejuni or Yersinia enterocolitica, intestinal salmonellosis and enterohemorrhagic E. coli infection). Compounds such as the fluoroquinolones, which are effective in the treatment of acute infectious diarrhea in adults, are not approved for use in children because of potential side effects. Many bacterial, viral, and parasitic organisms cause acute infectious diarrhea; appropriate antimicrobial therapy requires the accurate, rapid identification of the offending enteropathogen. In children with an underlying illness such as acquired immunodeficiency syndrome, manifestations may be prolonged, severe, and recurrent despite appropriate therapy.

In vitro synergy studies with Clostridium difficile

Agar dilution anaerobic susceptibility studies using rifampin, vancomycin, metronidazole, and bacitracin individually and in combination were performed with Clostridium difficile. Fifty-five strains of C. difficile were studied. Eighty-five percent of strains tested (29 of 34) were synergistically inhibited by the combination of bacitracin and rifampin (fractional inhibitory concentration, less than or equal to 0.50).