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

Abstract

The present study aimed to evaluate five nontoxigenic strains of Clostridium difficile (NTCD) in vitro and to select one strain to prevent C. difficile (CDI) infection in hamsters (Mesocricetus auratus

Evaluation of growth and sporulation of a non-toxigenic strain of Clostridioides difficile (Z31) and its shelf viability

“…It is known that spore production increases with incubation time, and recent studies have shown that even nonendemic strains can sporulate at high rates [25,33,41]. In this context, NTCD Z31 seems to be a strain with a relatively high sporulation rate, confirming a prior study where NTCD Z31 was the most efficient strain in spore production when compared to four NTCD isolated from different animals [22]. This is an important feature to consider for its possible use as a commercial preventive method, because the administration of spores, and not vegetative cells, has been shown to prevent the disease in piglets [12,20].…”

“…The complete sequence of the NTCD Z31 genome showed some desirable genes for virulence factors not related to toxin production, such as intestinal colonization (slpA) and biofilm formation (fliC and fliD), which are likely to be important from the perspective of competitive exclusion [21]. This strain also showed a higher spore production than other NTCDs previously isolated and it prevented CDI in 100% of exposed hamsters [22].…”

“…To determine the growth of Z31, the solution from each tube was homogenized, serially diluted in PBS, plated on AST, and incubated under anaerobic conditions for 2 days. To measure spore production, the same procedure was followed with the addition of a single heat treatment (20 min, 70°C) to eliminate the vegetative cells prior to the serial dilution [22,25]. Plates containing 30 to 300 colonies were used to determine the amount of Z31 from each culture in colony forming units per milliliter (CFU/mL).…”

“…CDI is an important disease in both humans and domestic animals and the use of bacterial probiotics could be a viable alternative to prevent this disease [12]. NTCD Z31 is a possible candidate to be used for the prevention of CDI, because it was able to prevent disease in 100% of treated hamsters [22]. Despite these results, it is essential to understand the in vitro growth and sporulation characteristics of the strain NTCD Z31 to assess the viability of its commercial use.…”

“…In Brazil, an NTCD strain (named Z31) isolated from a healthy dog presented promising results for CDI prevention. Whole genome sequencing demonstrated the presence of important genes related to colonization and sporulation [21], and studies in an experimental hamster model showed that the strain could prevent CDI in all of the animals tested [22]. Despite these promising results, the commercial utilization of NTCD to prevent CDI requires the significant in vitro Responsible Editor: Luis Augusto Nero production of these candidate strains as well as the maintenance of an acceptable shelf viability of their commercial form.…”