Effects of probiotics on pancreatic inflammation and intestinal integrity in mice with acute pancreatitis.

BACKGROUND: Severe acute pancreatitis is a potentially life-threatening disease. Despite being a common disorder, acute pancreatitis lacks a specific treatment. The present study aimed to examine the effects of probiotics on pancreatic inflammation and intestinal integrity in mice with acute pancreatitis. METHODS: Male ICR mice were randomly divided into 4 groups (n = 6 per group). The control group received two intraperitoneal (i.p.) injections of normal saline as a vehicle control. The acute pancreatitis (AP) group received two i.p. injections of L-arginine 450 mg/100 g body weight. AP plus probiotics groups received L-arginine to induce acute pancreatitis as above. In the single-strain and mixed-strain groups, mice received 1 mL of Lactobacillus plantarum B7 1 × 108 CFU/mL and 1 mL of Lactobacillus rhamnosus L34 1 × 108 CFU/mL and Lactobacillus paracasei B13 1 × 108 CFU/mL by oral gavage, respectively for 6 days starting 3 days prior to the AP induction. All mice were sacrificed 72 h after L-arginine injection. Pancreatic tissue was obtained for histological evaluation and immunohistochemical studies for myeloperoxidase, whereas ileal tissue was used for immunohistochemical studies for occludin, and claudin-1. Blood samples were collected for amylase analysis. RESULTS: Serum amylase levels and pancreatic myeloperoxidase levels in the AP group were significantly higher than in controls and significantly decreased in probiotic groups compared with the AP group. Ileal occludin and claudin-1 levels were significantly lower in the AP group than in controls. Ileal occludin levels significantly increased, whereas ileal claudin-1 levels did not significantly change in both probiotic groups as compared with the AP group. The pancreatic histopathology showed significantly higher degree of inflammation, edema, and fat necrosis in the AP group, and these changes improved in mixed-strained probiotic groups. CONCLUSIONS: Probiotics, particularly the mixed-strain ones, attenuated AP via the reduction of inflammation and the maintenance of intestinal integrity.

Diagnostic performance of the Anyplex MTB/NTM real-time PCR in detection of Mycobacterium tuberculosis complex and nontuberculous mycobacteria from pulmonary and extrapulmonary specimens.

Accurate and rapid diagnosis of mycobacterial infections is significant for appropriate treatment. In this study, we retrospectively evaluated the performance of the Anyplex MTB/NTM real-time detection assay (Anyplex MTB/NTM) compared to mycobacterial culture in detecting Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM) in 9,575 clinical specimens. For MTBC detection, the sensitivity, specificity, PPV, NPV, and percent agreement of the Anyplex MTB/NTM were 79.7%, 94.5%, 64.4%, 97.4%, and 92.9%, respectively. In pediatric patient (age ≤15) specimens, the Anyplex MTB/NTM demonstrated 84.8% sensitivity and 95.8% specificity. For NTM detection, the sensitivity, specificity, PPV, NPV, and percent agreement were 44.9%, 97.7%, 36.7%, 98.4%, and 96.2%, respectively. The sensitivity of the Anyplex MTB/NTM was enhanced in acid-fast bacilli (AFB) smear-positive specimens which was 97.7% and 80% for MTBC and NTM detection, respectively. The Anyplex MTB/NTM is a rapid tool for detection and differentiation of MTBC and NTM in clinical specimens.

Candida Worsens Klebsiella pneumoniae Induced-Sepsis in a Mouse Model with Low Dose Dextran Sulfate Solution through Gut Dysbiosis and Enhanced Inflammation.

Klebsiella pneumoniae is an opportunistic pathogen and a commensal organism that is possibly enhanced in several conditions with gut dysbiosis, and frequently detectable together with Candida overgrowth. Here, K. pneumoniae with or without Candida albicans was daily orally administered for 3 months in 0.8% dextran sulfate solution-induced mucositis mice and also tested in vitro. As such, Candida worsened Klebsiella-DSS-colitis as demonstrated by mortality, leaky gut (FITC-dextran assay, bacteremia, endotoxemia, and serum beta-glucan), gut dysbiosis (increased Deferribacteres from fecal microbiome analysis), liver pathology (histopathology), liver apoptosis (activated caspase 3), and cytokines (in serum and in the internal organs) when compared with Klebsiella-administered DSS mice. The combination of heat-killed Candida plus Klebsiella mildly facilitated inflammation in enterocytes (Caco-2), hepatocytes (HepG2), and THP-1-derived macrophages as indicated by supernatant cytokines or the gene expression. The addition of heat-killed Candida into Klebsiella preparations upregulated TLR-2, reduced Occludin (an intestinal tight junction molecule), and worsened enterocyte integrity (transepithelial electrical resistance) in Caco-2 and enhanced casp8 and casp9 (apoptosis genes) in HepG2 when compared with heat-killed Klebsiella alone. In conclusion, Candida enhanced enterocyte inflammation (partly through TLR-2 upregulation and gut dysbiosis) that induced gut translocation of endotoxin and beta-glucan causing hyper-inflammatory responses, especially in hepatocytes and macrophages.

Probiotics and their beneficial effects on alcohol-induced liver injury in a rat model: the role of fecal microbiota.

BACKGROUND: Current therapies for alcohol-induced liver injury are of limited efficacy and associated with significant side effects. With the proposed pathophysiology of alcohol-induced liver injury to be related to deranged gut microbiota, we hypothesized that probiotics would have beneficial effects in attenuating alcohol-induced liver injury. METHODS: Twenty-four male Sprague-Dawley rats were divided into 4 groups: control group, alcohol group, Lactobacillus plantarum group, and mixed-strain probiotics group. After 4 weeks, all rats were sacrificed, and blood samples were analyzed for ALT, lipopolysaccharide level (LPS), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Liver tissues were processed for histopathology, malondialdehyde (MDA) level and immunohistochemistry for toll-like receptors 4 (TLR-4). Stool samples were collected, and 16S rRNA sequencing was used to analyze the fecal microbiota. RESULTS: Liver histopathology showed the presence of significant hepatocyte ballooning in the alcohol group as compared with the control group, and the treatment with L. plantarum or mixed-strain probiotics alleviated these changes. Significant elevation of serum ALT, LPS, IL-6, and TNF-α, hepatic MDA levels, and hepatic TLR-4 expression were observed in alcohol-fed rats as compared with control rats. The administration of L. plantarum or mixed-strain probiotics restored these changes to the levels of control rats. The relative abundance of fecal bacteria at genus level showed a significant reduction in Allobaculum, Romboutsia, Bifidobacterium, and Akkermansia in the alcohol group as compared with the control group. In probiotics-treated rats, significant increases in Allobaculum and Bifidobacterium were observed, while the relative abundance of Romboutsia and Akkermansia was unchanged compared to the alcohol group. A reduction in alpha diversity was observed in alcohol-treated rats, whereas the improvement was noted after probiotic treatment. CONCLUSIONS: The treatment with Lactobacillus, whether as single-, or mixed-strain probiotics, was beneficial in reducing the severity of alcohol-induced liver injury likely through the increase in beneficial bacteria, and the reduction of inflammatory responses, and oxidative stress.

Uremia-Induced Gut Barrier Defect in 5/6 Nephrectomized Mice Is Worsened by Candida Administration through a Synergy of Uremic Toxin, Lipopolysaccharide, and (1➔3)-ß-D-Glucan, but Is Attenuated by Lacticaseibacillus rhamnosus L34.

A chronic kidney disease (CKD) causes uremic toxin accumulation and gut dysbiosis, which further induces gut leakage and worsening CKD. Lipopolysaccharide (LPS) of Gram-negative bacteria and (1➔3)-ß-D-glucan (BG) of fungi are the two most abundant gut microbial molecules. Due to limited data on the impact of intestinal fungi in CKD mouse models, the influences of gut fungi and Lacticaseibacillus rhamnosus L34 (L34) on CKD were investigated using oral C. albicans-administered 5/6 nephrectomy (5/6Nx) mice. At 16 weeks post-5/6Nx, Candida-5/6Nx mice demonstrated an increase in proteinuria, serum BG, serum cytokines (tumor necrotic factor-α; TNF-α and interleukin-6), alanine transaminase (ALT), and level of fecal dysbiosis (Proteobacteria on fecal microbiome) when compared to non-Candida-5/6Nx. However, serum creatinine, renal fibrosis, or gut barrier defect (FITC-dextran assay and endotoxemia) remained comparable between Candida- versus non-Candida-5/6Nx. The probiotics L34 attenuated several parameters in Candida-5/6Nx mice, including fecal dysbiosis (Proteobacteria and Bacteroides), gut leakage (fluorescein isothiocyanate (FITC)-dextran), gut-derived uremic toxin (trimethylamine-N-oxide; TMAO) and indoxyl sulfate; IS), cytokines, and ALT. In vitro, IS combined with LPS with or without BG enhanced the injury on Caco-2 enterocytes (transepithelial electrical resistance and FITC-dextran permeability) and bone marrow-derived macrophages (supernatant cytokines (TNF-α and interleukin-1 ß; IL-1ß) and inflammatory genes (TNF-α, IL-1ß, aryl hydrocarbon receptor, and nuclear factor-κB)), compared with non-IS activation. These injuries were attenuated by the probiotics condition media. In conclusion, Candida administration worsens kidney damage in 5/6Nx mice through systemic inflammation, partly from gut dysbiosis-induced uremic toxins, which were attenuated by the probiotics. The additive effects on cell injury from uremic toxin (IS) and microbial molecules (LPS and BG) on enterocytes and macrophages might be an important underlying mechanism.

Lactobacillus rhamnosus L34 attenuates chronic kidney disease progression in a 5/6 nephrectomy mouse model through the excretion of anti-inflammatory molecules.

BACKGROUND: Although pathogenic gut microbiota causes gut leakage, increases translocation of uremic toxins into circulation and accelerates CKD progression, the local strain of Lactobacillus rhamnosus L34 might attenuate gut leakage. We explored the effects of L34 on kidney fibrosis and levels of gut-derived uremic toxins (GDUTs) in 5/6 nephrectomy (5/6Nx) mice. METHODS: At 6 weeks post-5/6Nx in mice, either L34 (1 × 106 CFU) or phosphate buffer solution (as 5/6Nx control) was fed daily for 14 weeks. In vitro, the effects of L34-conditioned media with or without indoxyl sulfate (a representative GDUT) on inflammation and cell integrity (transepithelial electrical resistance; TEER) were assessed in Caco-2 (enterocytes). In parallel, the effects on proinflammatory cytokines and collagen expression were assessed in HK2 proximal tubular cells. RESULTS: At 20 weeks post-5/6Nx, L34-treated mice showed significantly fewer renal injuries, as evaluated by (i) kidney fibrosis area (P < 0.01) with lower serum creatinine and proteinuria, (ii) GDUT including trimethylamine-N-oxide (TMAO) (P = 0.02) and indoxyl sulfate (P < 0.01) and (iii) endotoxin (P = 0.03) and serum TNF-α (P = 0.01) than 5/6Nx controls. Fecal microbiome analysis revealed an increased proportion of Bacteroidetes in 5/6Nx controls. After incubation with indoxyl sulfate, Caco-2 enterocytes had higher interleukin-8 and nuclear factor κB expression and lower TEER values, and HK2 cells demonstrated higher gene expression of TNF-α, IL-6 and collagen (types III and IV). These indoxyl sulfate-activated parameters were attenuated with L34-conditioned media, indicating the protective role of L34 in enterocyte integrity and renal fibrogenesis. CONCLUSION: L34 attenuated uremia-induced systemic inflammation by reducing GDUTs and gut leakage that provided renoprotective effects in CKD.

Lacticaseibacillus casei Strain T21 Attenuates Clostridioides difficile Infection in a Murine Model Through Reduction of Inflammation and Gut Dysbiosis With Decreased Toxin Lethality and Enhanced Mucin Production.

Clostridioides difficile is a major cause of diarrhea in patients with antibiotic administration. Lacticaseibacillus casei T21, isolated from a human gastric biopsy, was tested in a murine C. difficile infection (CDI) model and colonic epithelial cells (Caco-2 and HT-29). Daily administration of L. casei T21 [1 × 108 colony forming units (CFU)/dose] for 4 days starting at 1 day before C. difficile challenge attenuated CDI as demonstrated by a reduction in mortality rate, weight loss, diarrhea, gut leakage, gut dysbiosis, intestinal pathology changes, and levels of pro-inflammatory cytokines [interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, macrophage inflammatory protein 2 (MIP-2), and keratinocyte chemoattractant (KC)] in the intestinal tissue and serum. Conditioned media from L. casei T21 exerted biological activities that fight against C. difficile as demonstrated in colonic epithelial cells by the following: (i) suppression of gene expression and production of IL-8, an important chemokine involved in C. difficile pathogenesis, (ii) reduction in the expression of SLC11A1 (solute carrier family 11 member 1) and HuR (human antigen R), important genes for the lethality of C. difficile toxin B, (iii) augmentation of intestinal integrity, and (iv) up-regulation of MUC2, a mucosal protective gene. These results supported the therapeutic potential of L. casei T21 for CDI and the need for further study on the intervention capabilities of CDI.

Lactobacillus rhamnosus attenuates Thai chili extracts induced gut inflammation and dysbiosis despite capsaicin bactericidal effect against the probiotics, a possible toxicity of high dose capsaicin.

Because of a possible impact of capsaicin in the high concentrations on enterocyte injury (cytotoxicity) and bactericidal activity on probiotics, Lactobacillus rhamnosus L34 (L34) and Lactobacillus rhamnosus GG (LGG), the probiotics derived from Thai and Caucasian population, respectively, were tested in the chili-extract administered C57BL/6 mice and in vitro experiments. In comparison with placebo, 2 weeks administration of the extract from Thai chili in mice caused loose feces and induced intestinal permeability defect as indicated by FITC-dextran assay and the reduction in tight junction molecules (occludin and zona occludens-1) using fluorescent staining and gene expression by quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, the chili extracts also induced the translocation of gut pathogen molecules; lipopolysaccharide (LPS) and (1→3)-ß-d-glucan (BG) and fecal dysbiosis (microbiome analysis), including reduced Firmicutes, increased Bacteroides, and enhanced total Gram-negative bacteria in feces. Both L34 and LGG attenuated gut barrier defect (FITC-dextran, the fluorescent staining and gene expression of tight junction molecules) but not improved fecal consistency. Additionally, high concentrations of capsaicin (0.02-2 mM) damage enterocytes (Caco-2 and HT-29) as indicated by cell viability test, supernatant cytokine (IL-8), transepithelial electrical resistance (TEER) and transepithelial FITC-dextran (4.4 kDa) but were attenuated by Lactobacillus condition media (LCM) from both probiotic-strains. The 24 h incubation with 2 mM capsaicin (but not the lower concentrations) reduced the abundance of LGG (but not L34) implying a higher capsaicin tolerance of L34. However, Lactobacillus rhamnosus fecal abundance, using qRT-PCR, of L34 or LGG after 3, 7, and 20 days of the administration in the Thai healthy volunteers demonstrated the similarity between both strains. In conclusion, high dose chili extracts impaired gut permeability and induced gut dysbiosis but were attenuated by probiotics. Despite a better capsaicin tolerance of L34 compared with LGG in vitro, L34 abundance in feces was not different to LGG in the healthy volunteers. More studies on probiotics with a higher intake of chili in human are interesting.

Candida Administration Worsens Uremia-Induced Gut Leakage in Bilateral Nephrectomy Mice, an Impact of Gut Fungi and Organismal Molecules in Uremia.

The impact of gut fungi and (1→3)-ß-d-glucan (BG), a major fungal cell wall component, on uremia was explored by Candida albicans oral administration in bilateral nephrectomy (BiNx) mice because of the prominence of C. albicans in the human intestine but not in mice. As such, BiNx with Candida administration (BiNx-Candida) enhanced intestinal injury (colon cytokines and apoptosis), gut leakage (fluorescein isothiocyanate [FITC]-dextran assay, endotoxemia, serum BG, and bacteremia), systemic inflammation, and liver injury at 48 h postsurgery compared with non-Candida BiNx mice. Interestingly, uremia-induced enterocyte apoptosis was severe enough for gut translocation of viable bacteria, as indicated by culture positivity for bacteria in blood, mesenteric lymph nodes (MLNs), and other organs, which was more severe in BiNx-Candida than in non-Candida BiNx mice. Candida induced alterations in the gut microbiota of BiNx mice as indicated by (i) the higher fungal burdens in the feces of BiNx-Candida mice than in sham-Candida mice by culture methods and (ii) increased Bacteroides with decreased Firmicutes and reduced bacterial diversity in the feces of BiNx-Candida mice compared with non-Candida BiNx mice by fecal microbiome analysis. In addition, lipopolysaccharide plus BG (LPS+BG), compared with each molecule alone, induced high supernatant cytokine levels, which were enhanced by uremic mouse serum in both hepatocytes (HepG2 cells) and macrophages (RAW264.7 cells). Moreover, LPS+BG, but not each molecule alone, reduced the glycolysis capacity and mitochondrial function in HepG2 cells as determined by extracellular flux analysis. Additionally, a probiotic, Lactobacillus rhamnosus L34 (L34), attenuated disease severity only in BiNx-Candida mice but not in non-Candida BiNx mice, as indicated by liver injury and serum cytokines through the attenuation of gut leakage, the fecal abundance of fungi, and fecal bacterial diversity but not fecal Gram-negative bacteria. In conclusion, Candida enhanced BiNx severity through the worsening of gut leakage and microbiota alterations that resulted in bacteremia, endotoxemia, and glucanemia.IMPORTANCE The impact of fungi in the intestine on acute uremia was demonstrated by the oral administration of Candida albicans in mice with the removal of both kidneys. Because fungi in the mouse intestine are less abundant than in humans, a Candida-administered mouse model has more resemblance to patient conditions. Accordingly, acute uremia, without Candida, induced intestinal mucosal injury, which resulted in the translocation of endotoxin, a major molecule of gut bacteria, from the intestine into blood circulation. In acute uremia with Candida, intestinal injury was more severe due to fungi and the alteration in intestinal bacteria (increased Bacteroides with decreased Firmicutes), leading to the gut translocation of both endotoxin from gut bacteria and (1→3)-ß-d-glucan from Candida, which synergistically enhanced systemic inflammation in acute uremia. Both pathogen-associated molecules were delivered to the liver and induced hepatocyte inflammatory responses with a reduced energy production capacity, resulting in acute uremia-induced liver injury. In addition, Lactobacillus rhamnosus attenuated intestinal injury through reduced gut Candida and improved intestinal bacterial conditions.

Corrigendum: Candida Administration Worsens Cecal Ligation and Puncture-Induced Sepsis in Obese Mice Through Gut Dysbiosis Enhanced Systemic Inflammation, Impact of Pathogen-Associated Molecules From Gut Translocation and Saturated Fatty Acid.

[This corrects the article DOI: 10.3389/fimmu.2020.561652.].

Evaluation of Anyplex™ II MTB/MDR kit's performance to rapidly detect isoniazid and rifampicin resistant Mycobacterium tuberculosis from various clinical specimens.

To determine the accuracy of multiplex real-time PCR (Anyplex™ II MTB/MDR kit) in detecting Isoniazid (INH)- and Rifampin (RIF)-resistant Mycobacterium tuberculosis strains from various clinical specimens. The performance of Anyplex™ II MTB/MDR kit in detecting INH- and RIF-resistant M. tuberculosis compared to the conventional drug susceptibility tests by Mycobacterial Growth Indicator Tube (MGIT). A total of 430 clinical samples had positive results for M. tuberculosis from both Anyplex™ II MTB/MDR kit assay and mycobacterial cultures by MGIT method. When compared to MGITs, the sensitivity and specificity of Anyplex™ II MTB/MDR kit in detecting INH-resistant TB were 85.71% and 99.75%, respectively. For the detection of MDR-TB, the sensitivity and specificity of the test were 82.35% and 99.76%, respectively. The positive predictive values and negative predictive values to detect INH-resistant TB were 96.77% and 98.75%, respectively. Anyplex™ II MTB/MDR kit can be used to rapidly detect isoniazid and rifampicin resistances. It has a high sensitivity, specificity and PPV in detecting INH-resistant TB and MDR-TB. This test can be used as an alternative test to Xpert MTB/RIF because it can rapidly detect both INH-resistant TB and RIF-resistant TB.

Additional Candida albicans administration enhances the severity of dextran sulfate solution induced colitis mouse model through leaky gut-enhanced systemic inflammation and gut-dysbiosis but attenuated by Lactobacillus rhamnosus L34.

CANDIDA ALBICANS: is abundant in the human gut mycobiota but this species does not colonize the mouse gastrointestinal tract. C. albicans administration in dextran-sulfate solution (DSS) induced-colitis mouse model (DSS+Candida) might resemble more to human condition, therefore, a DSS colitis model with Candida administration was studied; first, to test the influence of fungi in DSS model and second, to test the efficacy of Lactobacillus rhamnosus L34. We demonstrated serum (1→3)-ß-D-glucan (BG) elevation in patients with IBD and endoscopic moderate colitis in clinical remission, supporting the possible influence of gut fungi toward IBD in human. Then, in mouse model, Candida gavage was found to worsen the DSS model indicated by higher mortality rate, more severe colon histology and enhanced gut-leakage (FITC-dextran assay, endotoxemia, serum BG and blood bacterial burdens) but did not affect weight loss and diarrhea. DSS+Candida induced higher pro-inflammatory cytokines both in blood and in intestinal tissue. Worsened systemic pro-inflammatory cytokine responses in DSS+Candida compared with DSS alone was possibly due to the more severe translocation of LPS, BG and bacteria (not fungemia) from gut into systemic circulation. Interestingly, bacteremia from Pseudomonas aeruginosa was more frequently isolated from DSS+Candida than DSS alone. In parallel, P. aeruginosa was also isolated from fecal culture in most of the mice in DSS+Candida group supported by prominent Gammaproteobacteria in fecal microbioata analysis. However, L. rhamnosus L34 attenuated both DSS+Candida and DSS model through the attenuation of gut local inflammation (cytokines and histology), gut-leakage severity, fecal dysbiosis (culture method and microbiome analysis) and systemic inflammation (serum cytokines). In conclusion, gut Candida in DSS model induced fecal bacterial dysbiosis and enhanced leaky-gut induced bacteremia. Probiotic treatment strategy aiming to reduce gut-fungi and fecal dysbiosis could attenuate disease severity. Investigation on gut fungi in patients with IBD is highly interesting.

Administration of Candida Albicans to Dextran Sulfate Solution Treated Mice Causes Intestinal Dysbiosis, Emergence and Dissemination of Intestinal Pseudomonas Aeruginosa and Lethal Sepsis.

The influence of gut fungi in chronic colitis was investigated by repeated oral administration of Candida albicans in a 3% dextran sulfate solution (DSS) induced-colitis mouse model. Candida administration in the DSS (DSS+Candida) model enhanced the mortality rate and induced bacteremia (without candidemia) resulting from a gut perm-selectivity defect despite similar diarrheal severity in mice treated with DSS alone. The dominant fecal bacteria in DSS+Candida and DSS alone mice were Pseudomonas spp. and Enterobacter spp., respectively, implying that Candida induced gut dysbiosis. Interestingly, chloramphenicol-resistant bacterial colonies, predominantly Pseudomonas spp., appeared in the feces and blood of DSS+Candida mice (not the DSS alone group) during fungal culture. These antibiotic-resistant bacteria were also isolated, ex vivo, by incubating mouse feces with DSS and heat-killed Candida or (1→3)-ß-D-glucan, suggesting bacterial fermentation on fungi. Administration of Pseudomonas aeruginosa isolated from chloramphenicol-resistant bacteria in the DSS+Candida model enhanced the severity of disease, and increased growth of isolated P aeruginosa in blood agar containing heat-killed Candida was demonstrated. These data suggested the selection of a highly virulent bacterial strain following fecal Candida presentation in the gut. Additionally, reduction of fecal fungi with fluconazole decreased the burden of chloramphenicol-resistant bacteria, attenuating the severity of DSS+Candida. In conclusion, gut Candida induced bacteremia in the DSS model through an inflammation-induced gut perm-selectivity defect and facilitated the growth of some gut bacteria. Treatment strategies aimed at reducing gut fungi could attenuate disease severity. Further investigation of gut fungi in inflammatory bowel disease is warranted.

Oral Candida administration in a Clostridium difficile mouse model worsens disease severity but is attenuated by Bifidobacterium.

Gut fungi may influence the course of Clostridium difficile infection either positively or negatively for the host. Fungi are not prominent in the mouse gut, and C. albicans, the major human gastrointestinal commensal yeast, is in low abundance or absent in mice. Bifidobacterium is one of the probiotics that may attenuate the severity of C. difficile infection. Inflammatory synergy between C. albicans and C. difficile, in gut, may provide a state that more closely resembles human infection and be more suitable for testing probiotic effects. We performed fecal mycobiota analysis and administered C. albicans at 1 day prior to C. difficile dosing. Fecal eukaryotic 18S rDNA analysis demonstrated the presence of Ascomycota, specifically, Candida spp., after oral antibiotics, despite negative fecal fungal culture. C. albicans administration enhanced the severity of the C. difficile infection model as determined by mortality rate, weight loss, gut leakage (FITC-dextran assay), and serum and intestinal tissue cytokines. This occurred without increased fecal C. difficile or bacteremia, in comparison with C. difficile gavage alone. Candida lysate with C. difficile increased IL-8 production from HT-29 and Caco-2 human intestinal epithelial cell-lines. Bifidobacterium attenuated the disease severity of the C. difficile plus Candida model. The reduced severity was associated with decreased Candida burdens in feces. In conclusion, gut C. albicans worsened C. difficile infection, possibly through exacerbation of inflammation. Hence, a mouse model of Clostridium difficile infection with C. albicans present in the gut may better model the human patient condition. Gut fungal mycobiome investigation in patients with C. difficile is warranted and may suggest therapeutic targets.

Helicobacter pylori Infection Increased Anti-dsDNA and Enhanced Lupus Severity in Symptomatic FcγRIIb-Deficient Lupus Mice.

The defect on Fc gamma receptor IIb (FcγRIIb), the only inhibitory FcγR, has been identified as one of the genetic factors increasing susceptibility to lupus. The prevalence of Helicobacter pylori (HP) and FcγRIIb dysfunction-polymorphisms are high among Asians, and their co-existence is possible. Unfortunately, the influence of HP against lupus progression in patients with lupus is still controversial. In this study, the interactions between these conditions were tested with HP infection in 24-week-old FcγRIIb-/- mice (symptomatic lupus). HP induced failure to thrive, increased stomach bacterial burdens and stomach injury (histology and cytokines) in both wild-type and FcγRIIb-/- mice. While the severity of HP infection, as determined by these parameters, was not different between both strains, antibodies production (anti-HP, anti-dsDNA and serum gammaglobulin) were higher in FcγRIIb-/- mice compared to wild-type. Accordingly, HP infection also accelerated the severity of lupus as determined by proteinuria, serum creatinine, serum cytokines, renal histology, and renal immune complex deposition. Although HP increased serum cytokines in both wild-type and FcγRIIb-/- mice, the levels were higher in FcγRIIb-/- mice. As such, HP also increased spleen weight and induced several splenic immune cells responsible for antibody productions (activated B cell, plasma cell and follicular helper T cell) in FcγRIIb-/- mice, but not in wild-type. These data describe the different systemic responses against localized HP infection from diverse host genetic background. In conclusion, the mutual interactions between HP and lupus manifestations of FcγRIIb-/-mice were demonstrated in this study. With the prominent immune responses from the loss of inhibitory signaling in FcγRIIb-/- mice, HP infection in these mice induced intense chronic inflammation, increased antibody production, and enhanced lupus severity. Thus, the increased systemic inflammatory responses due to localized HP inducing gastritis in some patients with lupus may enhance lupus progression. More studies are needed.

Lactobacillus rhamnosus L34 Attenuates Gut Translocation-Induced Bacterial Sepsis in Murine Models of Leaky Gut.

Gastrointestinal (GI) bacterial translocation in sepsis is well known, but the role of Lactobacillus species probiotics is still controversial. We evaluated the therapeutic effects of Lactobacillus rhamnosus L34 in a new sepsis model of oral administration of pathogenic bacteria with GI leakage induced by either an antibiotic cocktail (ATB) and/or dextran sulfate sodium (DSS). GI leakage with ATB, DSS, and DSS plus ATB (DSS+ATB) was demonstrated by fluorescein isothiocyanate (FITC)-dextran translocation to the circulation. The administration of pathogenic bacteria, either Klebsiella pneumoniae or Salmonella enterica serovar Typhimurium, enhanced translocation. Bacteremia was demonstrated within 24 h in 50 to 88% of mice with GI leakage plus the administration of pathogenic bacteria but not with GI leakage induction alone or bacterial gavage alone. Salmonella bacteremia was found in only 16 to 29% and 0% of mice with Salmonella and Klebsiella administrations, respectively. Klebsiella bacteremia was demonstrated in 25 to 33% and 10 to 16% of mice with Klebsiella and Salmonella administrations, respectively. Lactobacillus rhamnosus L34 attenuated GI leakage in these models, as shown by the reductions of FITC-dextran gut translocation, serum interleukin-6 (IL-6) levels, bacteremia, and sepsis mortality. The reduction in the amount of fecal Salmonella bacteria with Lactobacillus treatment was demonstrated. In addition, an anti-inflammatory effect of the conditioned medium from Lactobacillus rhamnosus L34 was also demonstrated by the attenuation of cytokine production in colonic epithelial cells in vitro In conclusion, Lactobacillus rhamnosus L34 attenuated the severity of symptoms in a murine sepsis model induced by GI leakage and the administration of pathogenic bacteria.

Gastrointestinal Colonization of Candida Albicans Increases Serum (1→3)-ß-D-Glucan, without Candidemia, and Worsens Cecal Ligation and Puncture Sepsis in Murine Model.

The role of intestinal Candida albicans in bacterial sepsis, in the absence of candidemia, was investigated in murine models. Live C albicans or normal saline solution (NSS) was administered orally once, followed by 5 days of daily oral antibiotic-mixtures (ATB). Cecal ligation and puncture (CLP) was then performed to induce sepsis.Fecal Candida was detected by culture only in models with Candida administration. Oral Candida administration with/without ATB enhanced gut-pathogenic bacteria as determined by microbiome analysis. Despite negative candidemia, serum (1→3)-ß-D-glucan (BG) was higher in CLP with Candida preconditioning models than in CLP-controls (NSS-preconditioning) at 6 and/or 18 h post-CLP. Blood bacterial burdens were not increased with Candida administration.Additionally, CLP with high-dose Candida (10 colony forming units) induced higher levels of fecal Candida, serum BG, serum IL-6, and mortality than the lowest dose (100 colony forming units). Interestingly, fluconazole attenuated fecal Candida and improved survival in mice with live-Candida administration, but not in the CLP-controls. Heat-killed Candida preparations or their supernatants reduced bone marrow-derived macrophage killing activity in vitro but enhanced cytokine production.In conclusion, intestinal abundance of fungi and/or fungal-molecules was associated with increased bacterial sepsis severity, perhaps through cytokine storm induction and/or decreased macrophage killing activity. These observations suggest that further investigation of the potential role of intestinal fungal burdens in sepsis is warranted.

Oral administration of live- or heat-killed Candida albicans worsened cecal ligation and puncture sepsis in a murine model possibly due to an increased serum (1→3)-ß-D-glucan.

Candida albicans is the most common fungus in the human intestinal microbiota but not in mice. To make a murine sepsis model more closely resemble human sepsis and to explore the role of intestinal C. albicans, in the absence of candidemia, in bacterial sepsis, live- or heat-killed C. albicans was orally administered to mice at 3h prior to cecal ligation and puncture (CLP). A higher mortality rate of CLP was demonstrated with Candida-administration (live- or heat-killed) prior to CLP. Fecal Candida presented only in experiments with live-Candida administration. Despite the absence of candidemia, serum (1→3)-ß-D-glucan (BG) was higher in CLP with Candida-administration than CLP-controls (normal saline administration) at 6h and/or 18h post-CLP. Interestingly, fluconazole attenuated the fecal Candida burden and improved survival in mice with live-Candida administration, but not CLP-control. Microbiota analysis revealed increased Bacteroides spp. and reduced Lactobacillus spp. in feces after Candida administration. Additionally, synergy in the elicitation of cytokine production from bone marrow-derived macrophages, in vitro, was demonstrated by co-exposure to heat-killed E. coli and BG. In conclusion, intestinal abundance of fungi and/or fungal-molecules was associated with increased bacterial sepsis-severity, perhaps through enhanced cytokine elicitation induced by synergistic responses to molecules from gut-derived bacteria and fungi. Conversely, reducing intestinal fungal burdens decreased serum BG and attenuated sepsis in our model.

Characterization of Lactobacillus salivarius strains B37 and B60 capable of inhibiting IL-8 production in Helicobacter pylori-stimulated gastric epithelial cells.

BACKGROUND: Interleukin (IL)-8 is the key agent for initiating an inflammatory response to infection with Helicobacter pylori. Some strains of Lactobacillus spp. are known to colonize the stomach and suppress inflammation caused by H. pylori. In this study, we characterized two gastric-derived lactobacilli, Lactobacillus salivarius (LS) strains B37 and B60, capable of inhibiting H. pylori-induced IL-8 production by gastric epithelial cells. RESULTS: Conditioned media from LS-B37 and LS-B60 suppressed H. pylori-induced IL-8 production and mRNA expression from AGS cells without inhibiting H. pylori growth. These conditioned media suppressed the activation of NF-κB but did not suppress c-Jun activation. IL-8 inhibitory substances in conditioned media of LS-B37 and LS-B60 are heat-stable and larger than 100 kDa in size. The inhibitory activity of LS-B37 was abolished when the conditioned medium was treated with α-amylase but still remained when treated with either proteinase K, trypsin, lipase or lysozyme. The activity of LS-B60 was abolished when the conditioned medium was treated with either amylase or proteinase K but still remained when treated with lysozyme. Treatment with lipase and trypsin also significantly affected the inhibitory activity of LS-B60 although the conditioned medium retained IL-8 suppression statistically different from media control. CONCLUSIONS: These results suggest that L. salivarius strains B37 and B60 produce different immunomodulatory factors capable of suppressing H. pylori-induced IL-8 production from gastric epithelial cells. Our results suggest that the large, heat-stable immunomodulatory substance(s) present in the LCM of LS-B37 is a polysaccharide, while the one(s) of LS-B60 is either complex consisting of components of polysaccharide, lipid and protein or includes multiple components such as glycoprotein and lipoprotein.

Evaluation of gastrointestinal leakage using serum (1→3)-ß-D-glucan in a Clostridium difficile murine model.

Gastrointestinal (GI) leakage in Clostridium difficile-associated diarrhea (CDAD) is well known but is not routinely assessed in clinical practice. Serum (1→3)-ß-D-glucan (BG), a fungal cell wall component used as a biomarker for invasive fungal disease, was tested in a CDAD mouse model with and without probiotics. Higher serum fluorescein isothiocyanate-dextran (FITC-dextran) and spontaneous gram-negative bacteremia, GI leakage indicators, were frequently found in CDAD mice, which died compared with those which survived. BG, serum macrophage inflammatory protein-2 and FITC-dextran but not quantitative blood bacterial count differentiated the clinical severity. Interestingly, a specific dose of Lactobacillus rhamnosus L34 attenuated CDAD and decreased serum BG and FITC-dextran, but not other parameters. BG also showed a higher area under the receiver operating characteristic curve for 7-day mortality than FITC-dextran. Fifty-five percent of CDAD mice with BG ≥ 60 pg/ml (the human negative cut-off value for invasive fungal disease) at 1 day after C. difficile gavage died within 7 days. In conclusion, S: erum BG was elevated in mice with severe CDAD, an established model of GI leakage with a strong association with mortality rate. BG monitoring in patients with CDAD is of interest as both a potential prognostic tool and a therapeutic efficacy indicator.