Weissella is a genus earlier considered a member of the family Leuconostocaceae, which was reclassified into the family Lactobacillaceae in 1993. Recently, there have been studies emphasizing the probiotic and anti-inflammatory potential of various species of Weissella, of which W. confusa and W. cibaria are the most representative. Other species within this genus include: W. paramesenteroides, W. viridescens, W. halotolerans, W. minor, W. kandleri, W. soli, W. ghanensis, W. hellenica, W. thailandensis, W. fabalis, W. cryptocerci, W. koreensis, W. beninensis, W. fabaria, W. oryzae, W. ceti, W. uvarum, W. bombi, W. sagaensis, W. kimchi, W. muntiaci, W. jogaejeotgali, W. coleopterorum, W. hanii, W. salipiscis, and W. diestrammenae. Weissella confusa, W. paramesenteroides, W. koreensis, and W. cibaria are among the few species that have been isolated from human samples, although the identification of these and other species is possible using metagenomics, as we have shown for inflammatory bowel disease (IBD) and healthy controls. We were able to isolate Weissella in gut-associated bacteria (post 24 h food deprivation and laxatives). Other sources of isolation include fermented food, soil, and skin/gut/saliva of insects/animals. With the potential for hospital and industrial applications, there is a concern about possible infections. Herein, we present the current applications of Weissella on its antimicrobial and anti-inflammatory mechanistic effects, the predisposing factors (e.g., vancomycin) for pathogenicity in humans, and the antimicrobials used in patients. To address the medical concerns, we examined 28 case reports focused on W. confusa and found that 78.5% of infections were bacteremia (of which 7 were fatal; 1 for lack of treatment), 8 were associated with underlying malignancies, and 8 with gastrointestinal procedures/diseases of which 2 were Crohn’s disease patients. In cases of a successful resolution, commonly administered antibiotics included: cephalosporin, ampicillin, piperacillin-tazobactam, and daptomycin. Despite reports of Weissella-related infections, the evolving mechanistic findings suggest that Weissella are clinically treatable bacteria with emerging antimicrobial and probiotic benefits ranging from oral health, skin care, obesity, and inflammatory diseases to cancer.

The ability of probiotics, comprising live microbiota, to modulate the composition of intestinal microbiomes has been connected to modulation of the central nervous system (Gut–Brain axis), neuroendocrine system (Gut–Skin axis), and immune response (Gut–Immune axis). Less information is known regarding the ability of postbiotics (cell wall components and secreted metabolites derived from live organisms) to regulate host immunity. In the present study, we tested postbiotics comprising single strains of bacteria and yeast (Lactobacillus acidophilus 16axg, Lacticaseibacillus rhamnosus 18fx, Saccharomyces cerevisiae var. boulardii 16mxg) as well as combinations of multiple strains for their ability to stimulate cytokine production by human CD14⁺ monocytes. We quantified cytokine gene and protein expression levels in monocytes following stimulation with postbiotics. Both heat-killed L. acidophilus and L. rhamnosus stimulated naïve monocytes without significant differences between them. Heat-killed S. boulardii stimulated less cytokine production compared to postbiotic bacteria at the same concentration. Interestingly, the addition of heat-killed yeast to heat-killed L. acidophilus and L. rhamnosus resulted in an enhancement of immune stimulation. Thus, heat-killed postbiotics have immune-modulating potential, particularly when bacteria and yeast are combined. This approach may hold promise for developing targeted interventions that can be fine-tuned to modulate host immune response with beneficial health impact.

Candida (C.) infections represent a serious health risk for people affected by inflammatory bowel disease. An important fungal virulence factor is the capacity of the fungus to form biofilms on the colonized surface of the host. This research study aimed to determine the effect of a C. tropicalis and C. albicans co-infection on dextran sodium sulfate (DSS)-induced colitis in mice. The colitis severity was evaluated using histology and a colonoscopy. The mice were mono-inoculated with C. albicans or C. tropicalis or co-challenged with both species. The mice were administered 3% DSS to induce acute colitis. The biofilm activity was assessed using (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl] 2H-tetrazoliumhydroxide (XTT) and dry-weight assays. The abundance of C. albicans in the colon tissues was assessed by immunohistochemistry. The co-challenged mice showed a decreased colitis severity compared to the mono-inoculated mice. The dry-weight assay demonstrated a marked decrease in C. albicans biofilm production in a C. albicans culture incubated with C. tropicalis supernatant. Immunohistochemical staining showed that C. albicans was more abundant in the mucosa of C. albicans mono-inoculated mice compared to the co-inoculated group. These data indicate an antagonistic microbial interaction between the two Candida species, where C. tropicalis may produce molecules capable of limiting the ability of C. albicans to adhere to the host intestinal surface, leading to a reduction in biofilm formation.

Faecalibacterium prausnitzii, a major butyrate-producing gut commensal with anti-inflammatory activity, is extremely oxygen-sensitive, limiting its use as a probiotic. Dietary prebiotics may enhance its growth and resilience, thereby influencing host immune responses. This study examined how distinct classes of prebiotics including oligosaccharides (fructooligosaccharides, arabinoxylan), nondigestible polysaccharides (inulin, pectin, resistant starch, golden kiwi fiber), and the vitamin riboflavin affect the growth kinetics, bile tolerance, and immunomodulatory properties of F. prausnitzii. Doubling times were quantified in MRS medium supplemented with 0–2% prebiotics, bile tolerance was assessed under 0–0.5% bile salts, and immunomodulatory response was evaluated by measuring TNF-α expression in monocytic THP-1 cells exposed to bacterial supernatants. All prebiotics significantly reduced doubling times compared with controls, with FOSs, inulin, pectin, resistant starch, and riboflavin showing clear dose-dependent stimulation. Prebiotics also mitigated bile-induced growth delays, though with substrate-specific patterns; pectin and FOSs conferred the strongest protection. Culture supernatants significantly altered TNF-α expression, with pectin inducing the greatest response, followed by arabinoxylan, FOSs, and golden kiwi fiber. Overall, prebiotics enhanced F. prausnitzii growth, increased stress resilience, and differentially modulated immune-related metabolites. Pectin emerged as a particularly effective substrate for promoting microbial function and host-relevant immunomodulation.

Candida (C.) infections represent a serious health risk for people affected by inflammatory bowel disease. An important fungal virulence factor is the capacity to form biofilms on the colonized surface of the host. This research study aimed to determine the effect of C. tropicalis and C. albicans co-infection on dextran sodium sulfate (DSS)-induced colitis in mice. Colitis severity was evaluated using histology and colonoscopy. Mice were mono-inoculated with C. albicans, C. tropicalis or co-challenged with both species. Mice were administered 3% DSS to induce acute colitis. Biofilm activity was assessed using (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl] 2H-tetrazoliumhydroxide (XTT) assay. Abundance of C. albicans in the colon tissues was assessed by immunohistochemistry. Co-challenged mice showed decreased colitis severity compared to mono-inoculated mice. The XTT assay demonstrated a marked decrease of C. albicans biofilm production in a C. albicans culture incubated with C. tropicalis supernatant. Immunohistochemical staining showed that C. albicans was more abundant in the mucosa of C. albicans mono-inoculated mice compared to the co-inoculated group. These data indicate an antagonistic microbial interaction between the two Candida species, where C. tropicalis may produce molecules capable of limiting the ability of C. albicans to adhere to the host intestinal surface leading to a reduction in biofilm formation.

Acetyl-CoA and other acyl-CoA thioesters are critical intermediates in the metabolic reactions that cells rely on to produce energy and carry out biosynthesis. Therefore, the analysis of acyl-CoA provides valuable information about the metabolic activity of cells, especially when combined with stable isotope tracing. Acyl-CoA species are routinely monitored by reversed-phase liquid chromatography coupled to tandem mass spectrometry (RPLC-MS/MS). However, drastic differences in the hydrophobicity of short-chain versus long-chain acyl-CoA species have been challenging to accommodate with a single set of RPLC conditions. Here, we describe a convenient method based on hydrophilic interaction liquid chromatography (HILIC-MS/MS) for the concurrent detection of both short-chain and long-chain acyl-CoA and their corresponding acyl-carnitine species. Using this strategy, we tracked the metabolism of isotope-labeled fatty acids in multiple cell lines, which revealed differences in their propensities for fatty acid oxidation and the extent to which isotope incorporation into acyl-CoA mirrored that of acyl-carnitine. We also applied the HILIC-MS/MS workflow to the analysis of NADH and ATP, making it a useful technique for gauging cellular bioenergetics as reflected by the acetyl-CoA/CoA, NADH/NAD ⁺ , and ATP/ADP ratios. Altogether, this HILIC-MS/MS platform enables a streamlined analysis of acyl-CoA species and other key intermediates in cell metabolism.