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This review focuses on the characteristic of major fish bacteria, antimicrobial resistance and antibiotic substitution in aquaculture. Nowadays aquaculture represents the fastest growing industry leading to the use of intensive and semi-intensive methods resulting in outbreaks of bacterial diseases. Antibiotics are used to treat and prevent these bacterial diseases, which can cause an increase in resistance. Many antibiotics applied in aquaculture were originally used in human medicine and many countries do not have strict limits for their application. Annually, more than 700 000 people worldwide die from bacterial infections caused by bacteria resistant to antibiotics and even though European countries have strict rules for the use of antibiotics, the death rate resulting from resistance represents more than 33 000 people per year. One of the options how to resolve this problem is the replacement of antibiotics with bioactive compounds of plant origin that exhibit strong inhibitory activity against pathogenic bacteria.

The diseases of the urinary tract in small animal medicine, especially in dogs and cats, occur frequently with different etiologies. The most common cause of urinary tract infections (UTIs) are bacteria which enter upwards through the urethral opening. UTIs occur in hosts with compromised defence mechanisms in which the virulent microbes can adhere, multiply and persist in the urinary tract. In addition to bacteria, also viruses or fungi may infect the urinary tracts. Bacterial infection can develop in the upper (kidneys and ureters) or lower (bladder, urethra) urinary tract and are manifested by various clinical signs such as: frequent or difficult and painful urination, presence of blood in the urine, or its foul odour. The symptoms in sick animals are often accompanied by fever, discomfort, and loss of appetite. The UTIs in dogs and cats are caused by both Gram-negative (e. g. Escherichia coli, Pseudomonas aeruginosa, Klebsiella spp., Proteus spp.) and Gram-positive (e. g. Staphylococcus spp., Streptococcus spp., and Enterococcus spp.) bacteria. The properly performed aseptic sampling of the urine is one of the most important steps in bacteriological diagnostics. In this study, 105 urine samples were collected from dogs and cats. The cultivation, microscopy and biochemical examinations were used for species identification. Finally, the bacteriological examination included also determining the susceptibility of pathogens against antibiotics by the disc-diffusion method. The results were processed and expressed as a percentage according to identified pathogens, animal species, sex, breed and age. The uropathogens were diagnosed mainly in males aged 7—10 years. The most commonly identified pathogens were Escherichia coli, Streptococcus spp. and Staphylococcus spp. Tests of bacterial susceptibility to antibiotics showed that enrofloxacin, cefotaxime, and cephazolin were the most effective against uropathogens.

This study aimed to evaluate the immunomodulatory effect of the probiotic Limosilactobacillus reuteri L26 Biocenol TM (L26) and its purified exopolysaccharide (EPS) with respect to antiviral innate immune response. In our experiment, we used porcine epithelial IPEC-J2 cells as a model of the intestinal barrier in a homologous infection by porcine Rotavirus   A  strain OSU6 (RVA). The production of selected molecules of non-specific humoral immunity was evaluated at the mRNA level. The EPS alone significantly increased the level of interferon λ3 (IFN-λ3) mRNA in the non-infected IPEC-J2 cells ( P  < 0.001). We also tested whether the treatment of IPEC-J2 cells by L26 or EPS influences the replication of RVA by virus titration and real-time PCR. We found that a pre-treatment in combination with subsequent continuous stimulation has no influence on the RVA replication. However, both treatments significantly decreased the RVA-induced production of IFN-λ3 ( P  < 0.05) and the "SOS" cytokine interleukin 6 (IL-6; P  < 0.01), already at the transcription level. In addition, the EPS treatment resulted in significantly increased IL-10 mRNA in the RVA-infected cells. In summary, we assume an immunoregulatory potential of  L. reuteri L26 Biocenol TM and its EPS in the local intestinal antiviral immune response., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2024 Schusterova et al.)

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.

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.