The aim of this study was to investigate the use of a standardized animal model subjected to antibiotic treatment, and the effects of this treatment on the course of dextran sodium sulphate (DSS)-induced colitis in mice. By decontamination with selective antibiotics and observation of pathogenesis of ulcerative colitis (UC) induced chemically by exposure of mice to various concentrations of DSS, we obtained an optimum animal PGF model of acute UC manifested by mucin depletion, epithelial degeneration and necrosis, leading to the disappearance of epithelial cells, infiltration of lamina propria and submucosa with neutrophils, cryptitis, and accompanied by decreased viability of intestinal microbiota, loss of body weight, dehydration, moderate rectal bleeding, and a decrease in the selected markers of cellular proliferation and apoptosis. The obtained PGF model did not exhibit changes that could contribute to inflammation by means of alteration of the metabolic status and the induced dysbiosis did not serve as a bearer of pathogenic microorganisms participating in development of ulcerative colitis. The inflammatory process was induced particularly by exposure to DSS and its toxic action on compactness and integrity of mucosal barrier in the large intestine. This offers new possibilities of the use of this animal model in studies with or without participation of pathogenic microbiota in IBD pathogenesis.

Staphylococci are common pathogens in dogs, causing a variety of dermatological problems. This study aimed to characterize the prevalence, antibiotic resistance, and biofilm-forming potential of Staphylococcus species isolated from the skin of shelter dogs. Overall, 108 samples were collected from the hairless skin areas of dogs in a shelter over one year. Isolates were cultured using standard microbiological methods and identified through biochemical testing, MALDI-TOF MS, and multiplex PCR. A total of 67 Staphylococcus isolates were identified, with S. pseudintermedius being the most prevalent. Antibiotic susceptibility was assessed using disk diffusion and MIC methods, revealing high resistance to ampicillin, erythromycin, and tetracycline. Notably, 12 multidrug-resistant SIG (S. intermedius group; S. pseudintermedius) and 4 CoNS strains (coagulase-negative staphylococci; S. equorum) were identified. Biofilm production was evaluated using a crystal violet assay, showing variable biofilm-forming capabilities among isolates and PCR, to confirm genes associated with biofilm formation. These findings highlight the presence of multidrug-resistant Staphylococcus species in shelter dogs, emphasizing the need for careful monitoring and antibiotic stewardship to manage potential risks to both animal and human health.

Transplantation of faecal microbiota (FMT) is generally considered a safe therapeutic procedure with few adverse effects. The main factors that limit the spread of the use of FMT therapy for idiopathic inflammatory bowel disease (IBD) are the necessity of minimising the risk of infection and transfer of another disease. Obtaining the animal model of UC (ulcerative colitis) by exposure to DSS (dextran sodium sulphate) depends on many factors that significantly affect the result. Per os intake of DSS with water is individual for each animal and results in the development of a range of various forms of induced UC. For this reason, the aim of our study was to evaluate the modulation and regenerative effects of FMT on the clinical and histopathological responses and the changes in the bowel microenvironment in pseudo germ-free (PGF) mice of the BALB/c line subjected to chemical induction of mild, moderate and serious forms of UC. The goal was to obtain new data related to the safety and effectiveness of FMT that can contribute to its improved and optimised use. The animals with mild and moderate forms of UC subjected to FMT treatment exhibited lower severity of the disease and markedly lower damage to the colon, including reduced clinical and histological disease index and decreased inflammatory response of colon mucosa. However, FMT treatment failed to achieve the expected therapeutic effect in animals with the serious form of UC activity. The results of our study indicated a potential safety risk involving development of bacteraemia and also translocation of non-pathogenic representatives of bowel microbiota associated with FMT treatment of animals with a diagnosed serious form of UC.

Besides the properties typical of body cavities, the oral cavity exhibits many differentiating features that allow it to occupy position of an autonomous functional and biological unit, a characteristic ecosystem. An appropriate homeostasis of oral biocenosis and balanced conditions for microorganisms concerning proportions of physiological and pathogenic or potentially pathogenic microbiota play an important role with regard to the oral cavity health and eventually the overall health of an individual. The oral cavity is a constantly changing habitat. The current market offers a number of relevant preparations supporting oral health, and alternative approaches serving these purposes are also available. Results of the studies that focused on microbiocenosis of the dental plaque and interactions between individual bacterial species indicate a probiotic potential of some oral bacteria and their prospective use in prevention of oral cavity diseases. This chapter deals with the state of physiological microbiota found in oral biofilms, with the most important infections of the oral cavity and the potential use of probiotics as a prospective alternative approach to prevention and therapy of oral cavity diseases.

Objectives: The aim of this study was to confirm the effectiveness of FMT on the basis of optimum composition of the faecal microbiota of the donor for support therapy in patients with ulcerative colitis, and to observe the viability of the microbiota in frozen and lyophilised administration forms of FMT under various storage conditions. Methods: The bacterial microbiota composition of the FMT samples was assessed using amplicon sequencing via next-generation sequencing (NGS) technology, conducted on the Illumina MiSeq platform. The BD FACS Canto flow cytometer was used to analyse the metabolic activity of FMT samples. Results: FMT analysis confirmed the presence of key butyrate-producing organisms, specifically highlighting species such as Bifidobacterium adolescentis, Faecalibacterium prausnitzi, Coprococcus catus, Eubacterium rectale, alongside contributions from genera Roseburia and Blautia. These organisms play a crucial role in maintaining intestinal health in humans. The viable microorganism counts were significantly higher (p < 0.001) in the frozen form of FMT (−70 °C) in comparison to lyophilised forms (−70 °C, 4 °C and 20 °C) throughout the storage period. Conclusion: The conducted NGS analyses allowed us to confirm the suitability of our FMT donor as a potential candidate for the target group of patients diagnosed with ulcerative colitis. From the point of view of optimum utilisation of FMT at its highest metabolic activity for the purpose of transplantation, its storage for a maximum of 2 months under specified conditions was confirmed as the most suitable for the frozen and all lyophilised FMT forms.

Research on autism spectrum disorders (ASDs) has so far focused primarily on the gut–brain axis, whereas the role of the gut–liver axis remains insufficiently explored. The aim of this study was to evaluate whether microbiota derived from girls with ASD induces dysbiotic changes in gut microbiota composition and leads to alterations in gut–liver axis processes in pseudo-germ-free (PGF) BALB/c mice. We also examined whether these processes could be modulated by altering the gut microbiota using the probiotic strains Lactiplantibacillus plantarum CCM 7512 and Limosilactobacillus reuteri CCM 8617 in combination with ground flaxseed (Linum usitatissimum L.) as a source of omega-3 polyunsaturated fatty acids and fermentable fiber. Colonization with fecal microbiota derived from girls with ASD resulted in dysbiotic changes in the composition of the cecal microbiota, characterized by an increased relative abundance of Escherichia–Shigella, Fusobacterium, Alistipes, and the Ruminococcus gnavus group. These changes were accompanied by impaired intestinal mucosal integrity, altered metabolomic pathways related mainly to aromatic amino acids and lipid metabolism, increased hepatic immunoreactivity of iNOS and COX-2, and elevated activity of the liver-specific LDH-5 isoenzyme. These results suggest that synbiotic intervention contributed to remodeling of the cecal microbiota composition, restoration of intestinal epithelial integrity, and modulation of metabolomic pathways, which was reflected by reduced immunoreactivity of iNOS and COX-2 in liver tissue and decreased activity of the LDH-5 isoenzyme. These findings support the role of microbiota-mediated metabolic processes in communication between the gut and the liver within the gut–liver axis.