Disturbance in gut microbiota is crucial for the development of Clostridioides difficile infection (CDI). Different mechanisms through which gut microbiota influences C. difficile colonization are known. However, C. difficile could also affect gut microbiota balance as previously demonstrated by cultivation of fecal microbiota in C. difficile conditioned medium. In current study, the interactions of C. difficile cells with gut microbiota were addressed. Three different strains (ribotypes 027, 014/020, and 010) were co-cultivated with two types of fecal microbiota (healthy and dysbiotic) using in vitro batch model. While all strains showed higher sporulation frequency in the presence of dysbiotic fecal microbiota, the growth was strain dependent. C. difficile either proliferated to comparable levels in the presence of dysbiotic and healthy fecal microbiota or grew better in co-culture with dysbiotic microbiota. In co-cultures with any C. difficile strain fecal microbiota showed decreased richness and diversity. Dysbiotic fecal microbiota was more affected after co-culture with C. difficile than healthy microbiota. Altogether, 62 OTUs were significantly changed in co-cultures of dysbiotic microbiota/C. difficile and 45 OTUs in co-cultures of healthy microbiota/C. difficile. However, the majority of significantly changed OTUs in both types of microbiota belonged to the phylum Firmicutes with Lachnospiraceae and Ruminococcaceae origin.

The milk and mammary gland (MG) microbiome can be influenced by several factors, such as mode of delivery, breastfeeding, maternal lifestyle, health status, and diet. An increasing number of studies show a variety of positive effects of consumption of probiotics during pregnancy and breastfeeding on the mother and the newborn. The aim of this study was to investigate the effect of oral administration of probiotics Lactobacillus gasseri K7 (LK7) and Lactobacillus rhamnosus GG (LGG) during pregnancy and lactation on microbiota of the mouse mesenteric lymph nodes (MLN), MG, and milk. Pregnant FVB/N mice were fed skim milk or probiotics LGG or LK7 resuspended in skim milk during gestation and lactation. On d 3 and 8 postpartum, blood, feces, MLN, MG, and milk were analyzed for the presence of LGG or LK7. The effects of probiotics on MLN, MG, and milk microbiota was evaluated by real-time PCR and by 16S ribosomal DNA 454-pyrosequencing. In 5 of 8 fecal samples from the LGG group and in 5 of 8 fecal samples from the LK7 group, more than 1 × 10(3) of live LGG or LK7 bacterial cells were detected, respectively, whereas no viable LGG or LK7 cells were detected in the control group. Live lactic acid bacteria but no LGG or LK7 were detected in blood, MLN, and MG. Both probiotics significantly increased the total bacterial load as assessed by copies of 16S ribosomal DNA in MLN, and a similar trend was observed in MG. Metagenomic sequencing revealed that both probiotics increased the abundance of Firmicutes in MG, especially the abundance of lactic acid bacteria. The Lactobacillus genus appeared exclusively in MG from probiotic groups. Both probiotics influenced MLN microbiota by decreasing diversity (Chao1) and increasing the distribution of species (Shannon index). The LGG probiotic also affected the MG microbiota as it increased diversity and distribution of species and proportions of the genera Lactobacillus and Bifidobacterium. These results provide evidence that probiotics can modulate the bacterial composition of MLN and MG microbiota in ways that could improve the health of the MG and, ultimately, the health of the newborn.

Clostridium difficile infection (CDI) is typically associated with disturbed gut microbiota and changes related to decreased colonization resistance against C. difficile are well described. However, nothing is known about possible effects of C. difficile on gut microbiota restoration during or after CDI. In this study, we have mimicked such a situation by using C. difficile conditioned medium of six different C. difficile strains belonging to PCR ribotypes 027 and 014/020 for cultivation of fecal microbiota. A marked decrease of microbial diversity was observed in conditioned medium of both tested ribotypes. The majority of differences occurred within the phylum Firmicutes, with a general decrease of gut commensals with putative protective functions (i.e. Lactobacillus, Clostridium_XIVa) and an increase in opportunistic pathogens (i.e. Enterococcus). Bacterial populations in conditioned medium differed between the two C. difficile ribotypes, 027 and 014/020 and are likely associated with nutrient availability. Fecal microbiota cultivated in medium conditioned by E. coli, Salmonella Enteritidis or Staphylococcus epidermidis grouped together and was clearly different from microbiota cultivated in C. difficile conditioned medium suggesting that C. difficile effects are specific. Our results show that the changes observed in microbiota of CDI patients are partially directly influenced by C. difficile.

Clostridioides difficile (Clostridium difficile) infection (CDI) is one of the main public health concerns in adults, while children under 2 years of age are often colonized asymptomatically. In both adults and children, CDI is strongly associated with disturbances in gut microbiota. In this study, an in-vitro model of children gut microbiota was challenged with vegetative cells or a conditioned media of six different toxigenic C. difficile strains belonging to the ribotypes 027, 078, and 176. In the presence of C. difficile or conditioned medium the children gut microbiota diversity decreased and all main phyla (Bacteroidetes, Firmicutes, and Proteobacteria) were affected. The NMR metabolic spectra divided C. difficile exposed children gut microbiota into three clusters. The grouping correlated with nine metabolites (short chain fatty acids, ethanol, phenolic acids and tyramine). All strains were able to grow in the presence of children gut microbiota and showed a high sporulation rate of up to 57%. This high sporulation rate in combination with high asymptomatic carriage in children could contribute to the understanding of the reported role of children in C. difficile transmissions.

IntroductionCoronavirus disease 2019 (COVID-19) disease increases risk of venous thromboembolisms (VTE), primarily deep vein thrombosis and pulmonary embolism. Only a few cases of cerebral venous sinus thrombosis (CVST) in association with a COVID-19 infection have been reported and are limited to acute COVID-19 disease. Hypercoagulable conditions persist in postacute COVID-19 disease, which carries an increased risk of VTE.Case presentationWe report a case of CVST and stroke 56 days post-COVID-19 infection presenting with an atypical clinical picture.DiscussionTo the best of our knowledge, this is one of the first observations of CVST in the postacute phase of COVID-19 disease. Clinicians should be aware of this potential late complication and should consider appropriate diagnostic imaging techniques in patients with COVID-19-infection history.