Caseous lymphadenitis (CLA) is a worldwide disease of small ruminants caused by Corynebacterium pseudotuberculosis, a facultative intracellular pathogen that is able to survive and multiply in certain white blood cells of the host. In this study, 33 strains of C. pseudotuberculosis were isolated from sheep and goats suffering from CLA on nine farms in the Czech Republic. All these strains were tested for their antibiotic susceptibility, ability to form a biofilm and resistance to the effects of commonly used disinfectant agents. To better understand the virulence of C. pseudotuberculosis, the genomes of strains were sequenced and comparative genomic analysis was performed with another 123 genomes of the same species, including ovis and equi biovars, downloaded from the NCBI. The genetic determinants for the virulence factors responsible for adherence and virulence factors specialized for iron uptake and exotoxin phospholipase D were revealed in every analyzed genome. Carbohydrate-Active Enzymes were compared, revealing the presence of genetic determinants encoding exo-α-sialidase (GH33) and the CP40 protein in most of the analyzed genomes. Thirty-three Czech strains of C. pseudotuberculosis were identified as the biovar ovis on the basis of comparative genome analysis. All the compared genomes of the biovar ovis strains were highly similar regardless of their country of origin or host, reflecting their clonal behavior.

Gastrointestinal diseases in weaned piglets are a frequent cause of high morbidity and mortality in domestic pigs. The use of antibiotics is problematic due to increasing antibiotic resistance in bacterial populations, for which reason the use of suitable probiotics is highly recommended to maintain animal health and welfare. In this study, 57 strains of biologically safe lactic acid bacteria (LAB) and bifidobacteria originating from the gastrointestinal tract (GIT) of pigs were identified and characterized in terms of their probiotic properties for potential use in weaned piglets. These strains were divided into two sets based on their origin – from the GIT of wild boars (n = 41) and from the GIT of domestic pigs (n = 16). Strains obtained from wild boars exhibited greater taxonomic diversity compared to isolates from domestic pigs. While searching for coding sequences (CDS) encoding bacteriocins and bile salt hydrolases (BSH), no significant difference was detected between the two tested groups. On the other hand, CDS encoding adhesinlike factors were more frequent in the dataset isolated from wild boars than in the dataset obtained from domestic pigs. Moreover, more CDS encoding carbohydrateactive enzymes (CAZymes) were carried in the genomes of strains obtained from wild boars. Utilization of important selected carbohydrate substrates, such as starch, D-raffinose, D-mannose, Dcellobiose and gentiobiose, was confirmed by API testing. Antimicrobial activity against at least one of the five tested pathogens was found in 51% of wild boar strains but in none of the isolates from domestic pigs. This suggests that the intestinal microbiota of wild boars could serve as a promising source of probiotics for domestic pigs.

Probiotics are crucial components for maintaining a healthy gut microbiota in pigs, especially during the weaning period. Lactic acid bacteria (LAB) derived from the gastrointestinal tract of wild boars can serve as an abundant source of beneficial probiotic strains with suitable properties for use in pig husbandry. In this study, we analyzed and characterized 15 strains of Limosilactobacillus mucosae obtained from the gut contents of wild boars to assess their safety and suitability as probiotic candidates. The strains were compared using pan-genomic analysis with 49 L. mucosae strains obtained from the NCBI database. All isolated strains demonstrated their safety by showing an absence of transferrable antimicrobial resistance genes and hemolysin activity. Based on the presence of beneficial genes, five candidates with probiotic properties were selected and subjected to phenotypic profiling. These five selected isolates exhibited the ability to survive conditions mimicking passage through the host’s digestive tract, such as low pH and the presence of bile salts. Furthermore, five selected strains demonstrated the presence of corresponding carbohydrate-active enzymes and the ability to utilize various carbohydrate substrates. These strains can enhance the digestibility of oligosaccharide or polysaccharide substrates found in food or feed, specifically resistant starch, α-galactosides, cellobiose, gentiobiose, and arabinoxylans. Based on the results obtained, the L. mucosae isolates tested in this study appear to be promising candidates for use as probiotics in pigs.

Restrictions on the use of antibiotics in pigs lead to the continuous search for new probiotics serving as an alternative to antibiotics. One of the key parameters for probiotic bacteria selection is the absence of horizontally transmissible resistance genes. The aim of our study was to determine antibiotic susceptibility profiles in 28 Lactobacillus amylovorus isolates derived from the digestive tract of wild boars and farm pigs by means of the broth microdilution method and whole genome sequencing (WGS). We revealed genetic resistance determinants and examined sequences flanking resistance genes in these strains. Our findings indicate that L. amylovorus strains from domestic pigs are predominantly resistant to tetracycline, erythromycin and ampicillin. WGS analysis of horizontally transmissible genes revealed only three genetic determinants (tetW, ermB and aadE) of which all tetW and ermB genes were present only in strains derived from domestic pigs. Sequence analysis of coding sequences (CDS) in the neighborhood of the tetW gene revealed the presence of site-specific recombinase (xerC/D), site-specific DNA recombinase (spoIVCA) or DNA-binding transcriptional regulator (xre), usually directly downstream of the tetW gene. In the case of ermB, CDS for omega transcriptional repressor or mobilization protein were detected upstream of the ermB gene.

Using probiotics represents a?potential solution to?post-weaning diarrheal diseases in?piglets on?commercial farms. The gastrointestinal tract of?wild boars serves as?a?promising reservoir of?novel lactic acid bacteria with suitable probiotic ...