Padronização de um modelo de infecção por Clostridium difficile em hamsters sírios Mesocricetus auratus

Abstract

RESUMO O objetivo do presente trabalho foi padronizar um modelo de infecção por Clostridium diffi cile (ICD) em hamsters sírios (Mesocricetus auratus). Para seleção dos isolados capazes

Prevention of Clostridium difficile infection in hamsters using a non-toxigenic strain

“…The toxigenic strain was isolated only one and two days after challenge but without the presence of toxins. SILVA et al (2014a) observed the same results after animals not previously treated with antimicrobials were challenged with a toxigenic strain. The timely isolation with no detection of A/B toxins and/or clinical signs suggest that the toxigenic strain simply passed through the gastrointestinal tract without colonizing it, possibly because the colonization sites were already occupied by the NTCD strain.…”

“…In contrast, animals of the death control groups (IV and V) challenged with the C. difficile toxigenic strain died between 36 and 90h after being challenged and exhibited hemorrhagic typhlitis. In these groups, the isolation of the toxigenic strain and toxin detection were possible from the day after the animals were challenged until death, confirming CDI as the classification of SILVA et al (2014a). Hamsters in groups II and III, which received the NTCD strains, did not die, had no toxins detected in their intestinal contents, and exhibited no histological lesions.…”

“…In liquid culture medium in static conditions, concentrations exceeding 10 6 spores mL -1 (>6 log 10 ), such as those produced by the Z31 and R1 strains, are desirable. Considering the high dose suggested for CDI prevention in animals (10 7 spores animal -1 ), a strain able to produce a high amount of spores is of utmost importance to facilitate the prevention of C. difficile infection using a non-toxigenic strain (SILVA et al, 2014a). In other studies that use NTCD strains for CDI prevention in hamsters, there are no data on spore production by the evaluated strains (SAMBOL et al, 2002;NAGARO et al, 2013).…”

“…Six batches of spores per C. difficile strain were produced as described by SILVA et al (2014a). The concentration of each batch was determined by plating on blood agar enriched with 0.1% taurocholate.…”

Characterization of the virulence of three novel clade 2 Clostridioides (Clostridium) difficile strains and a two-year screening in animals and humans in Brazil

“…Spore production and spore quantification were performed according to previously described protocols [20,21]. Briefly, pure aliquots from each strain were plated onto Mu ¨ller Hinton agar (Oxoid, UK) supplemented with 7% horse blood and 0.1% sodium taurocholate (Sigma-Aldrich Co., USA), followed by anaerobic incubation at 37˚C for 48 h. After incubation, a suspension of C. difficile was prepared in sterile 0.85% saline using McFarland standard 1 as the reference.…”