Oritavancin May Thwart Tough-to-Treat C. Difficile Infection

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Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: Seniors / Aging;  MRSA / Drug Resistance
Article Date: 26 Apr 2008 - 14:00 PDT

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Oritavancin may be as effective as vancomycin in treating Clostridium (C.) difficile infection and may prevent recrudescence of C. difficile-induced spores, according to results released at the 18th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID).

C. difficile is a major cause of morbidity in the hospitalized elderly and is almost exclusively associated with antimicrobial therapy.

Dr. Simon D. Baines, with the University of Leeds (UK), and colleagues compared the efficacy of oritavancin and vancomycin for treating clindamycin-induced C. difficile ribotype 027 infection in an in vitro human gut model. Oritavancin is a new lipoglycopeptide, which has activity against Gram-positive bacteria, including drug-resistant pathogens.

"C. difficile infection is a nosocomial disease of increasing importance that may range in severity from mild diarrhea or colitis resulting from antibiotic treatment to life-threatening pseudomembranous colitis," Dr. Baines pointed out. "Although first-line treatment is currently limited to metronidazole or vancomycin, recent reports have challenged the efficacy of such therapies, particularly against an apparently hypervirulent C. difficile strain, PCR ribotype 027."

In fact, recurrence of C. difficile infection after antimicrobial therapy occurs in up to 20 percent of individuals, he said.

In the present investigation, oritavancin and vancomycin were both effective in reducing vegetative forms of C. difficile infection, Dr. Baines reported. However, only oritavancin appeared active against the spore forms of the bacteria. Thus, following a decline of vancomycin below the limits of detection, recrudescence of C. difficile spores was observed, characterized by germination, proliferation, and high-level cytotoxin production. Despite much lower concentrations of oritavancin within the vessel of the gut model, recrudescence of spores was not seen.

"Overall, the findings suggest that oritavancin may have an edge over vancomycin for recurrent C. difficile infection," Dr. Baines said.

He added that the data support the continued evaluation of oritavancin as a treatment for C. difficile infection.

Targanta Therapeutics, which is awaiting approval in the U.S. for an intravenous formulation of oritavancin to treat serious skin infections, announced recently that it was launching a program to develop an oral formulation of the drug to treat C. difficile infection. The company, based in Cambridge, Massachusetts, expects to begin clinical trials for this indication early next year.

-- Oritavancin Program

By Jill Stein
Jill Stein is a freelance medical writer based in Paris, France.
jillstein03 (@) gmail.com
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