Etiology of tetracycline-associated pseudomembranous colitis in hamsters

Reviewing the Clostridioides difficile Mouse Model: Insights into Infection Mechanisms

Clostridioides difficile is an anaerobic, spore-forming bacterium associated with intestinal infection, manifesting a broad spectrum of gastrointestinal symptoms, ranging from mild diarrhea to severe colitis. A primary risk factor for the development of C. difficile infection (CDI) is antibiotic exposure. Elderly and immunocompromised individuals are particularly vulnerable to CDI. A pivotal aspect for comprehending the complexities of this infection relies on the utilization of experimental models that mimic human CDI transmission, pathogenesis, and progression. These models offer invaluable insights into host-pathogen interactions and disease dynamics, and serve as essential tools for testing potential therapeutic approaches. In this review, we examine the animal model for CDI and delineate the stages of infection, with a specific focus on mice. Our objective is to offer an updated description of experimental models employed in the study of CDI, emphasizing both their strengths and limitations.

Predictive values of models of Clostridium difficile infection

In vivo and in vitro models are widely used to simulate Clostridium difficile infection (CDI). They have made considerable contributions in the study of C difficile pathogenesis, antibiotic predisposition to CDI, and population dynamics as well as the evaluation of new antimicrobial and immunologic therapeutics. Although CDI models have greatly increased understanding of this complicated pathogen, all have limitations in reproducing human disease, notably their inability to generate a truly reflective immune response. This review summarizes the most commonly used models of CDI and discusses their pros and cons and their predictive values in terms of clinical outcomes.

Models for the study of Clostridium difficile infection

Models of Clostridium difficile infection (C. difficile) have been used extensively for Clostridium difficile (C. difficile) research. The hamster model of C. difficile infection has been most extensively employed for the study of C. difficile and this has been used in many different areas of research, including the induction of C. difficile, the testing of new treatments, population dynamics and characterization of virulence. Investigations using in vitro models for C. difficile introduced the concept of colonization resistance, evaluated the role of antibiotics in C. difficile development, explored population dynamics and have been useful in the evaluation of C. difficile treatments. Experiments using models have major advantages over clinical studies and have been indispensible in furthering C. difficile research. It is important for future study programs to carefully consider the approach to use and therefore be better placed to inform the design and interpretation of clinical studies.

Prevention of clindamycin-induced mortality in hamsters by Saccharomyces boulardii

Saccharomyces boulardii, a yeast used in a number of countries for general and antibiotic-associated gastrointestinal illnesses, was examined for possible application in the prevention of clindamycin-induced mortality in the hamster colitis model. Hamsters were given free access to an aqueous 5% suspension of lyophilized yeast for 3 days before and 10 days after administration of a single oral clindamycin dose of from 0.2 to 0.8 mg/kg. Mortality was recorded in groups of 7 to 20 animals every 24 h for 10 to 30 days. Mean cecal concentrations of S. boulardii were greater than 10(6) CFU/ml throughout the yeast administration period. Yeast treatment significantly decreased cumulative percent mortality by an average of 29%. Death onset was not affected by yeast treatment. Cecitis was present in 86% of moribund animals (N = 95) and was absent in all surviving animals examined (N = 27). Toxigenic Clostridium difficile was isolated from 13 of 14 moribund hamsters examined. No adverse effects of the yeast treatment were observed in animals receiving S. boulardii without clindamycin. The results suggest that S. boulardii warrants further evaluation for the prevention of antibiotic-associated colitis.

Survey of the extrachromosomal gene pool of Clostridium difficile

Pseudomembranous colitis, a severe diarrheal disease, has been linked to the administration of antibiotics and to two toxins produced by Clostridium difficile. Eighty-two strains of C. difficile isolated from humans and hamsters were assayed for the presence of plasmid DNA. Agarose gel electrophoresis of Sarkosyl-lysed cells indicated that 18% of the strains contained from one to four plasmids. The plasmid DNA in these strains ranged in molecular weight from 2.7 X 10(6) to 60 X 10(6). Strains with and without plasmids were examined for the cytopathogenic effect of the toxins on MRC-5 cells. No correlation was observed between plasmid content and cytopathogenic effect. The results of in vitro antibiotic susceptibility testing with plasmid-containing strains revealed that 33% of the strains tested exhibited growth with four or more of the antimicrobial agents used.

In vitro susceptibility of Clostridium difficile isolates from patients with antibiotic-associated diarrhea or colitis

In vitro susceptibility tests were performed on 84 strains of Clostridium difficile to 11 antimicrobial agents. All isolates were from the stools of patients with antibiotic-associated diarrhea or colitis in which there was a cytopathic toxin that was neutralized by Clostridium sordellii antitoxin. Over 95% of the strains were susceptible to vancomycin, penicillin G, ampicillin, and metronidazole at concentrations of 4 microgram/ml. Susceptibility to clindamycin was variable; 60% of the strains were susceptible at 1 microgram/ml, and 9% were resistant at 128 microgram/ml. Studies of individual isolates showed that a major portion of the strains were relatively susceptible to the antimicrobial agent implicated in causing the disease.