Transgenic plants expressing a Clostridium difficile spore antigen as an approach to develop low-cost oral vaccines.

Gastrointestinal infections caused by Clostridium difficile lead to significant impact in terms of morbidity and mortality, causing from mild symptoms, such as a low-grade fever, watery stools, and minor abdominal cramping as well as more severe symptoms such as bloody diarrhea, pseudomembrane colitis, and toxic megacolon. Vaccination is a viable approach to fight against C. difficile and several efforts in this direction are ongoing. Plants are promising vaccine biofactories offering low cost, enhanced safety, and allow for the formulation of oral vaccines. Herein, the CdeM protein, which is a spore antigen associated with immunoprotection against C. difficile, was selected to begin the development of plant-based vaccine candidates. The vaccine antigen is based in a fusion protein (LTB-CdeM), carrying the CdeM antigen, fused to the carboxi-terminus of the B subunit of the Escherichia coli heat-labile enterotoxin (LTB) as a mucosal immunogenic carrier. LTB-CdeM was produced in plants using a synthetic optimized gene according codon usage and mRNA stability criteria. The obtained transformed tobacco lines produced the LTB-CdeM antigen in the range of 52-90 µg/g dry weight leaf tissues. The antigenicity of the plant-made LTB-CdeM antigen was evidenced by GM1-ELISA and immunogenicity assessment performed in test mice revealed that the LTB-CdeM antigen is orally immunogenic inducing humoral responses against CdeM epitopes. This report constitutes the first step in the development of plant-based vaccines against C. difficile infection.

Effect of antibiotic to induce Clostridioides difficile-susceptibility and infectious strain in a mouse model of Clostridioides difficile infection and recurrence.

The anaerobic bacterium Clostridioides difficile is the leading cause of antibiotic-associated diarrhea that can culminate in life-threating colitis. During the C. difficile infection (CDI), C. difficile produces toxins that generate the clinical symptoms of the disease, and produce spores, which persist in the host during antibiotic treatment and can cause recurrent CDI (R-CDI). In this work, we aimed to compare three antibiotic regimens in the susceptibility of mice to CDI and R-CDI (i.e., antibiotic cocktail followed by clindamycin, 5 days of cefoperazone and 10 days of cefoperazone) with three different C. difficile isolates (i.e., strains 630; R20291, and VPI 10463). We observed that the severity of the clinical symptoms of CDI and R-CDI was dependent on the antibiotic treatment used to induce C. difficile-susceptibility, and that the three strains generated a different onset to diarrhea and weight loss in mice that were administrated with the same antibiotic treatment and which differed in comparison to the effect previously reported by other research groups. Our results suggest that, in our experimental conditions, in those animals treated with antibiotic cocktail followed by clindamycin, infection with strain R20291 had the highest diarrhea manifestation in comparison to strains 630 and VPI 10463. In animals treated with cefoperazone for 5 days, infection with strains R20291 or 630 had the highest diarrhea manifestation in comparison to VPI 10463, while in animals treated with cefoperazone for 10 days, infection with strain R20291 or VPI 10463, but not 630, had the highest diarrhea manifestation.

Indomethacin increases severity of Clostridium difficile infection in mouse model.

AIM: To evaluate the effect on the nonsteroidal anti-inflammatory drug indomethacin on Clostridium difficile infection (CDI) severity. MATERIALS & METHODS: Indomethacin was administered in two different mouse models of antibiotic-associated CDI in two different facilities, using a low and high dose of indomethacin. RESULTS: Indomethacin administration caused weight loss, increased the signs of severe infection and worsened histopathological damage, leading to 100% mortality during CDI. Indomethacin-treated, antibiotic-exposed mice infected with C. difficile had enhanced intestinal inflammation with increased expression of KC, IL-1ß and IL-22 compared with infected mice unexposed to indomethacin. CONCLUSION: These results demonstrate a negative impact of nonsteroidal anti-inflammatory drugs on antibiotic-associated CDI in mice and suggest that targeting the synthesis or signaling of prostaglandins might be an approach to ameliorating the severity of CDI.

Assessing the Burden of Clostridium difficile Infection in Low- and Middle-Income Countries.

In contrast to the significant resources invested in the diagnosis and prevention of Clostridium difficile infection (CDI) in resource-rich settings, in resource-limited settings patients with community- and hospital-acquired diarrhea may not routinely be tested for CDI. Is CDI actually less frequent or severe in resource-limited settings, or might we be missing an important opportunity to prevent CDI-related morbidity and mortality (and to promote antibiotic stewardship) in these settings? Here, we review the literature to assess the overall burden of CDI in low- and middle-income countries.

Community-acquired diarrhea associated with Clostridium difficile in an HIV-positive cancer patient: first case report in Latin America.

Clostridium difficile is the most important cause of nosocomial diarrhea, mainly associated with antibiotic use and immunodeficiency. Although, an increased incidence of community-acquired C. difficile infection (CA-CDI) has been reported worldwide, this infection has been under-diagnosed in Latin America. This is the first report of a CA-CDI case in Latin America, in an HIV-positive patient with cancer.