Clostridioides difficile spores produced during infection are important for the recurrence of the disease. Here, we show that C. difficile spores gain entry into the intestinal mucosa via pathways dependent on host fibronectin-α5β1 and vitronectin-αvβ1. The exosporium protein BclA3, on the spore surface, is required for both entry pathways. Deletion of the bclA3 gene in C. difficile, or pharmacological inhibition of endocytosis using nystatin, leads to reduced entry into the intestinal mucosa and reduced recurrence of the disease in a mouse model. Our findings indicate that C. difficile spore entry into the intestinal barrier can contribute to spore persistence and infection recurrence, and suggest potential avenues for new therapies.

Clostridioides difficile spores produced during infection are essential for the recurrence of the disease. However, how C. difficile spores persist in the intestinal mucosa to cause recurrent infection remains unknown. Here, we show that C. difficile spores gain entry into the intestinal mucosa via fibronectin-α5β1 and vitronectin-αvβ1 specific-pathways. The spore-surface exosporium BclA3 protein is essential for both spore-entry pathways into intestinal epithelial cells. Furthermore, C. difficile spores of a bclA3 isogenic mutant exhibited reduced entry into the intestinal mucosa and reduced recurrence of the disease in a mouse model of the disease. Inhibition of C. difficile spore-entry led to reduced spore-entry into the intestinal epithelial barrier and recurrence of C. difficile infection in vivo. These findings suggest that C. difficile spore-entry into the intestinal barrier is a novel mechanism of spore-persistence that can contribute to infection recurrence and have implications for the rational design of therapies.

Multiple sclerosis (MS) is an autoimmune disease characterized by a robust inflammatory response against myelin sheath antigens, which causes astrocyte and microglial activation and demyelination of the central nervous system (CNS). Multiple genetic predispositions and environmental factors are known to influence the immune response in autoimmune diseases, such as MS, and in the experimental autoimmune encephalomyelitis (EAE) model. Although the predisposition to suffer from MS seems to be a multifactorial process, a highly sensitive period is pregnancy due to factors that alter the development and differentiation of the CNS and the immune system, which increases the offspring’s susceptibility to develop MS. In this regard, there is evidence that thyroid hormone deficiency during gestation, such as hypothyroidism or hypothyroxinemia, may increase susceptibility to autoimmune diseases such as MS. In this review, we discuss the relevance of the gestational period for the development of MS in adulthood.

Introducción: La infección genital por el Virus de Papiloma Humano (VPH) se ha asociado con el cáncer cérvicouterino (CCE) al provocar la aparición de lesiones precursoras de cáncer en la zona de transformación de la unión escamo-columnar del cuello uterino. Existen más de 100 tipos de VPH, clasificados en bajo riesgo oncogénico (VPH-BR) y alto riesgo oncogénico (VPH-AR). Estudios reportan la infección por genotipos de alto riesgo en el 100% de los CCE. En Venezuela, el 67,7% de los CCE, se relacionan con el genotipo de VPH-AR 16. Objetivo: Detectar la presencia de VPH en pacientes con cambios citológicos cervicouterino. Metodología: Se incluyeron 49 pacientes que presentaban cambios citológicos, se tomaron las muestras de la región endocervical y exocervical para la detección y genotipificación del virus mediante la técnica de Multiple PCR. Resultados: Las alteraciones citológicas presentes fueron Células Escamosas Atípicas (69,4%), Células Glandulares Atípicas (4,1%), Lesión Escamosa Intraepitelial de Bajo Grado (16,3%), y Lesión Escamosa Intraepitelial de Alto Grado (10,2%). La detección molecular demostró que 16,3% presentaba VPH, 62,5% correspondían a VPH-AR, 25% a VPH-BR, 12,5% al genotipo 16 y no se detectó el genotipo 18. Se reportó un solo caso de coinfección. Conclusiones: A diferencia de otros estudios, no se encontró una relación estadísticamente significativa entre la presencia del virus y la aparición de cambios citológicos cervicouterino en esta población. No obstante, se detectaron genotipos de alto riesgo oncogénico, lo que puede traducirse en una mayor incidencia de cáncer cervicouterino a futuro.

Interaction of Clostridioides difficile spores with the intestinal mucosa contributes to the persistence and recurrence of the infection. Advanced age is one of the main risk factors for C. difficile infection and recurrence of the disease. However, interaction of C. difficile spores with the intestinal mucosa during aging has not been evaluated. In the present work, using intestinal ligated loop technique in a mouse model, we analyzed C. difficile spore adherence and internalization to the ileum and colonic mucosa during aging. Additionally, we provide visual documentation of the critical steps of the procedure. Consequently, our data suggest that spore internalization in the ileum and colonic mucosa is higher in elderly mice rather than adults or young mice. Also, our data suggest that spore adherence to the ileum and colonic mucosa decreases with aging.

In the Methods, the incorrect supplier and catalogue number for an antibody was listed. The sentence 'phalloidin Alexa-Fluor 568 (#ab176753 Abcam, USA)' should read 'phalloidin Alexa-Fluor 568 (#A12380 Thermo Fisher, USA)'.The Methods, in the section 'Colonic and ileal loop assay ', originally incorrectly read 'To evaluate the effect of nystatin or RGD peptide in C. difficile spore internalization, mice were treated with 17,000 UI kg −1 nystatin (n = 4) 24 h before the surgery. In the loop, as control, mice were treated with 0.9% NaCl (saline; n = 4) then, ligated loops were injected with 3 × 10 C. difficile R20291. In the case of RGD, ligated loops were injected with 250 nmol of RGD peptide (n = 4)'. The correct version replaces this text with 'To evaluate the effect of nystatin and RGD peptide in C. difficile spore internalization in vivo, 24 h prior to surgery, mice (n = 4) were treated with nystatin (17,000 IU kg −1 ) in 100 µL of DPBS by oral gavage; control mice (n = 8; 4 for control and 4 for RGD treatment) where treated with 100 µL of DPBS by oral gavage. On the day of surgery, ileal and colonic ligated loops of control mice (n = 4) were injected with 100 µL of DPBS containing 3 × 10 8 C. difficile R20291 spores; ileal and colonic ligated loops of nystatin-treated mice (n = 4) were injected with 100 µL of DPBS containing 3 × 10 8 C. difficile R20291 spores and 340 IU (17,000 IU kg −1 ) nystatin; ileal and colonic ligated loops of RGD-treated mice (n = 4) were injected with 100 µL of DPBS containing 3 × 10 8 C. difficile R20291 spores and 86.6 µg (250 nM) of RGD peptide. DPBS was used to resuspend nystatin and RGD peptides because it rendered higher solubility than saline solution (0.9% weight vol −1 NaCl)'.The Methods, in the section 'Quantification of C. difficile spores from feces and colon of mice', originally incorrectly read '1.5% weight vol −1 (BD, USA; TCCFA plates)'. The correct version replaces this text with '1.5% weight vol −1 agar (BD, USA) (TCCFA plates)'.