Background: Salmonella is a common causative agent of food-borne illness in humans. Infection by this pathogen is usually due to ingestion of contaminated insufficiently cooked foods. Despite the fact that several studies of the prevalence and antimicrobial resistance of Salmonella have been conducted in Thailand, there is limited data available concerning the more rural areas of the country. Objectives: This study aimed to investigate the prevalence and antimicrobial resistance profiles of Salmonella in meat and vegetable samples taken from Phatthalung Province, Thailand. Materials and Methods: Pork and chicken meat and fresh vegetable samples were randomly selected from retail markets in Phatthalung Province. Salmonella isolation and identification were performed on the same day of sample collection. Serovar typing was performed by slide agglutination according to The Kauffman and White scheme. Antimicrobial susceptibility testing was performed by disc diffusion method, and antimicrobial susceptibility patterns were analyzed by the WHONET 5 program. Results: The prevalence of Salmonella in retail pork, chicken meat, and fresh vegetables were 82% (34/41), 67.5% (27/40), and 46% (37/80), respectively. The Salmonella isolated from pork, and vegetables were most resistant to tetracycline (77 and 33%) while the Salmonella isolated from chicken meat was most resistant to streptomycin (92%). Thirty-one samples (68%) isolated from pork and thirty-two samples (84%) isolated from chicken meat were of MDR strains. whereas only 7 samples (29%) isolated from vegetables exhibited resistance to two or more antimicrobial drugs. Conclusions: These results show that retail meat and vegetables can serve as a reservoir of multiple antimicrobial resistant Salmonella and can probably be a potential route of transmission of these pathogens into human population. Keywords: Salmonella enterica; Chicken; Pork

Background and Aim: Using antimicrobials as a feed additive in swine production is prohibited because it is a major cause of the emergence of antimicrobial-resistant bacteria. Probiotics such as Lactobacillus spp. are an attractive alternative to reduce antimicrobial resistance and promote swine growth. This study aimed to evaluate the in vitro probiotic properties of Lactobacillus isolated from indigenous swine manure. Materials and Methods: A total of 30 fecal samples from healthy individual indigenous pigs were collected and isolated on de Man, Rogosa, and Sharpe agar. The preliminary screen identified candidates with antibacterial activity against six pathogens and >50% survival and tolerance to acid (pH 3.0) and 1% bile salt. Isolates that passed the initial screen will be tested for other probiotic properties. Results: Of the 314 isolates from 30 pig manure samples, 17 isolates satisfied all initial conditions for probiotic properties. Each isolate has unique, distinctive properties. Isolates B4, B5, B8, B17, B87, and B144 formed thick biofilms, whereas isolates B5, B8, and 27 adhered well to the intestinal wall and exhibited strong autoaggregation properties. Isolate B4 aggregated with Enterohemorrhagic Escherichia coli and Enteropathogenic E. coli. Tests in pH-adjusted cell-free medium indicated that the antibacterial activity resulted from bacterial acidification rather than bacteriocin formation. Sequence analysis (16S rRNA) revealed 16 of the isolates were Lactobacillus plantarum, and only one isolate was Lactobacillus salivarius. Conclusion: We isolated 17 Lactobacillus from swine manure and demonstrated that their probiotic properties might be useful as a probiotic cocktail for swine feed.

Kittiya Khongkool, Malai Taweechotipatr, Sunchai Payungporn, Vorthon Sawaswong, and Monthon Lertworapreecha. J. Microbiol. Biotechnol. 2025;35:1-20. https://doi.org/10.4014/jmb.2503.03028

Background: Heyndrickxia coagulans, recognized for its probiotic attributes and resilience as an endospore-forming bacterium, is increasingly studied for health supplement applications. This study aimed to evaluate the probiotic potential and safety of novel H. coagulans isolated from stingless bee honey, a new source for this bacterium, and to characterize their multifunctional probiotic properties. Results: We isolated two novel H. coagulans, TBRC-18260 and TBRC-18261, and conducted comprehensive in vitro analyses to assess their probiotic traits such as acid and bile salt tolerance, self-aggregation, and pathogen inhibition. Both isolates were also evaluated for safety through antibiotic susceptibility testing and hemolytic activity. Functional properties, including GABA production, antioxidant activity, were examined to establish their potential as probiotics. TBRC-18260 and TBRC-18261 exhibited core probiotic characteristics and showed excellent survivability under acidic conditions and in the presence of bile salts. They displayed strong antimicrobial activity against various pathogens and demonstrated significant GABA production and antioxidant capabilities. The safety assessments confirmed their non-hemolytic nature and susceptibility to a wide range of antibiotics. Conclusion: The novel H. coagulans isolates, TBRC-18260 and TBRC-18261, with their robust probiotic properties, antioxidant activities, and safety profiles, emerged as promising candidates for the development of functional foods and dietary supplements. This study enhances the biodiversity of available probiotics and supports the continuous search for novel strains with unique health-promoting characteristics.

Background and Aim: The pursuit of sustainable alternatives to antibiotic growth promoters has intensified interest in spore-forming probiotics with fiber-degrading capabilities. This study aimed to isolate, characterize, and evaluate the safety and functional properties of Bacillus spp. from native Thai swine, focusing on strains with probiotic potential and enzymatic activity for application in livestock nutrition. Materials and Methods: Spore-forming Bacillus isolates were obtained from fecal samples of backyard-raised native pigs. Isolates were screened for acid and bile tolerance, autoaggregation, hydrophobicity, biofilm formation, adhesion to Caco-2 cells, antimicrobial activity, and co-aggregation with pathogens. Enzyme production (cellulase, xylanase, and pectinase), hemolytic activity, and antibiotic susceptibility were also assessed. The most promising strain, Bacillus amyloliquefaciens NL1.2, was subjected to in vivo safety and efficacy evaluations in a mouse model, including assessments of toxicity, histopathology, secretory immunoglobulin A (IgA) levels, and gut microbiome modulation through full-length 16S ribosomal RNA sequencing. Results: B. amyloliquefaciens NL1.2 exhibited robust probiotic traits including high acid (115.05%) and bile (75.16%) tolerance, strong autoaggregation (65.99%), moderate hydrophobicity (34.13%), and effective adhesion (2.0%) to intestinal epithelial cells. It produced fiber-degrading enzymes (cellulase: 0.015 U/mL; xylanase: 0.522 U/mL; and pectinase: 0.374 U/mL) showed antimicrobial activity against Enterohemorrhagic Escherichia coli, Enteropathogenic E. coli, and Salmonella Typhimurium, and was non-hemolytic and antibiotic-sensitive. In vivo, NL1.2 induced no adverse effects and significantly elevated intestinal secretory IgA levels (p < 0.05). Microbiome analysis revealed enrichment of beneficial taxa (e.g., Bacteroidetes and Barnesiella) and reduction of potentially pathogenic taxa (e.g., Helicobacter and Deferribacteres). Conclusion: B. amyloliquefaciens NL1.2 is a safe, multifunctional probiotic with fiber-degrading, immunomodulatory, and gut microbiota-modulating properties. Its origin from native swine and broad functional attributes highlights its potential as a next-generation feed additive for sustainable animal production. Keywords: Bacillus amyloliquefaciens, fiber-degrading enzymes, gut microbiome modulation, mucosal immunity, native swine feces, probiotics.