There are massive bacteria in the raw milk, especially the lactic acid bacteria (LABs), which have been considered probiotics in humans and animals for a long time. Novel probiotics are still urgently needed because of the rapid development of the probiotic industry. To obtain new LABs with high probiotic potential, we obtained 26 LAB isolates, named L1 ~ L26, from local Holstein raw milk collected from a farm whose milk had never been used for LAB isolation. We identified them at the species level by biochemical and 16S rDNA sequencing methods. Their antagonistic activities against four target pathogens (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa PAO1, and Salmonella enterica H9812), co-aggregative ability with these target pathogens, survivability in the simulated gastrointestinal tract conditions and phenol, auto-aggregation and hydrophobicity, hemolytic activity, and antibiotic susceptibility, were evaluated in vitro. Five Lactiplantibacillus plantarum isolates (L5, L14, L17, L19, and L20) showed more promising probiotic potential than others. Specifically, these five isolates conglutinated with and inhibited all the target pathogens, and survived in the simulated gastric juice (92.55 ~ 99.69%), intestinal juice (76.18 ~ 83.39%), and 0.4% phenol (76.95 ~ 88.91%); possessed considerable auto-aggregation (83.91 ~ 90.33% at 24 h) and hydrophobicity (79.32 ~ 92.70%); and were non-hemolytic, sensitive to kinds of common antimicrobials. Our findings demonstrated that these five isolates could be preliminarily determined as probiotic candidates because they have better probiotic potential than those previously reported. Again, this study highlighted the potential of raw milk for probiotic isolating and screening and provided the probiotic industry with five new LAB candidates.

The overabundant populations of wildlife have caused many negative impacts, such as human‐wildlife conflicts and ecological degradation. The existing approaches like injectable immunocontraceptive vaccines and lethal methods have limitations in many aspects, which has prompted the advancement of oral immunocontraceptive vaccine. There is growing interest in oral immunocontraceptive vaccines for reasons including high immunization coverage, easier administration, frequent boosting, the ability to induce systemic and mucosal immune responses, and cost‐effectiveness. Delivery systems have been developed to protect oral antigens and enhance the immunogenicity, including live vectors, microparticles and nanoparticles, bacterial ghosts, and mucosal adjuvants. However, currently, no effective oral immunocontraceptive vaccine is available for field trials because of the enormous development challenges, including biological and physicochemical barriers of the gastrointestinal tract, mucosal tolerance, pre‐existing immunity, antigen residence time in the small intestine, species specificity and other safety issues. To overcome these challenges, this article summarizes achievements in delivery systems and contraceptive antigens in oral immunocontraceptive vaccines and explores the potential barriers for future vaccine design and application.

This study evaluated the protective effect of Bacillus subtilis HH2 on beagles orally challenged with enterotoxigenic Escherichia coli (ETEC). We assessed the physiological parameters and the severity of diarrhea, as well as the changes in three serum immunoglobulins (IgG, IgA, and IgM), plasma diamine oxidase (DAO), D-lactate (D-LA), and the fecal microbiome. Feeding B. subtilis HH2 significantly reduced the severity of diarrhea after the ETEC challenge (p < 0.05) and increased serum levels of IgG, IgA, and IgM (p < 0.01). B. subtilis HH2 administration also reduced serum levels of DAO at 48 h after the ETEC challenge (p < 0.05), but no significant changes were observed in D-LA (p > 0.05). Oral ETEC challenge significantly reduced the richness and diversity of gut microbiota in beagles not pre-fed with B. subtilis HH2 (p < 0.05), while B. subtilis HH2 feeding and oral ETEC challenge significantly altered the gut microbiota structure of beagles (p < 0.01). Moreover, 14 days of B. subtilis HH2 feeding reduced the relative abundance of Deinococcus-Thermus in feces. This study reveals that B. subtilis HH2 alleviates diarrhea caused by ETEC, enhances non-specific immunity, reduces ETEC-induced damage to the intestinal mucosa, and regulates gut microbiota composition.

Enterocytozoon bieneusi and Encephalitozoon spp. are microsporidian pathogens with zoonotic potential that pose significant public health concerns. To ascertain the occurrence and genotypes of E. bieneusi and Encephalitozoon spp., we used nested PCR to amplify the internal transcribed spacer (ITS) gene and DNA sequencing to analyze 198 fecal samples from red pandas from 6 zoos in China. The total rate of microsporidial infection was 15.7% (31/198), with 12.1% (24/198), 1.0% (2/198), 2.0% (4/198) and 1.0% (2/198) for infection rate of E. bieneusi, Encephalitozoon cuniculi, Encephalitozoon intestinalis and Encephalitozoon hellem, respectively. One red panda was detected positive for a mixed infection (E. bieneusi and E. intestinalis). Red pandas living in semi-free conditions are more likely to be infected with microsporidia (χ2 = 6.212, df = 1, p < 0.05). Three known (SC02, D, and PL2) and one novel (SCR1) genotypes of E. bieneusi were found. Three genotypes of E. bieneusi (SC02, D, SCR1) were grouped into group 1 with public health importance, while genotype PL2 formed a separate clade associated with group 2. These findings suggest that red pandas may serve as a host reservoir for zoonotic microsporidia, potentially allowing transmission from red pandas to humans and other animals.

Corynebacterium pseudotuberculosis is a zoonotic pathogen that causes lymphadenitis in humans, livestock, and wildlife. In this study, C. pseudotuberculosis biovar equi strains were isolated from three alpacas. Antibiotic susceptibility tests and pathogenicity tests were also conducted. Moreover, one strain was sequenced using DNBSEQ and Oxford Nanopore technology. The three strains exhibited resistance to aztreonam, fosfomycin, and nitrofurantoin. The median lethal doses (LD50) of strains G1, S2 and BA3 in experimentally infected mice was 1.66 × 105 CFU, 3.78 × 105 CFU and 3.78 × 105 CFU, respectively. The sequencing of strain G1 resulted in the assembly of a chromosomal scaffold comprising 2,379,166 bp with a G + C content of 52.06%. Genome analysis of strain G1 revealed the presence of 48 virulence genes and 5 antibiotic resistance genes (ARGs). Comparative genomic analysis demonstrates a high degree of genetic similarity among C. pseudotuberculosis strains, in contrast to other Corynebacterium species, with a clear delineation between strains belonging to the two biovars (ovis and equi). The data of the present study contribute to a better understanding of the properties of C. pseudotuberculosis biovar equi strains and the potential risk they pose to alpacas and other livestock, as well as the necessity of ongoing surveillance and monitoring of infectious diseases in animals.