An Oral Formulation of the Probiotic, Bacillus subtilis HU58, Was Safe and Well Tolerated in a Pilot Study of Patients with Hepatic Encephalopathy.

BACKGROUND: Hepatic encephalopathy often results in high blood ammonia levels because of inefficient ammonia processing by the liver. Lactulose treatment promotes the growth of urease-producing gut bacteria and a reduced colon pH, thus reducing blood ammonia absorption. It is thought that probiotics as an add-on therapy may be beneficial. Patients and Methods. Bacillus subtilis HU58 was tested for safety and tolerability in patients with hepatic encephalopathy taking lactulose in this double-bind, placebo-controlled, 4-week pilot study. Study participants received one dose of B. subtilis HU58 or placebo (orally) for the first five days and two daily doses thereafter. Participants were monitored for safety and blood ammonia levels. RESULTS: Forty patients participated (placebo, 11; probiotic, 29). Baseline characteristics were generally comparable; the mean baseline blood ammonia level was somewhat higher in the probiotic group. Mild or moderate treatment-emergent adverse events (TEAEs) were reported in 27.3% and 17.2% of patients in the placebo and probiotic groups, respectively; no severe TEAEs were reported. One patient (9.1%) taking placebo and two (6.9%) taking the probiotic experienced serious TEAEs (SAEs); none resulted in study discontinuation and all were considered to have no/unlikely relationship to the study product. There were no significant differences in the mean percent change (MPC) of blood ammonia levels between groups, though the probiotic group exhibited a trend toward a milder increase. Stratification of the probiotic group by baseline blood ammonia level (>60 µg/dL and ≤60 µg/dL) resulted in a significantly reduced MPC in the >60 µg/dL subgroup (MPC (SD); ≤60 µg/dL (n = 14), 35.3% (73.3); >60 µg/dL (n = 14), -26.5% (24.4); p = 0.0087). CONCLUSIONS: Daily treatment with oral B. subtilis HU58 was safe and well tolerated over a 4-week period in patients with hepatic encephalopathy, and a significantly reduced MPC of blood ammonia level was observed in patients with a baseline level >60 µg/dL.

Bacillus subtilis HU58 and Bacillus coagulans SC208 Probiotics Reduced the Effects of Antibiotic-Induced Gut Microbiome Dysbiosis in An M-SHIME® Model.

Benefits associated with probiotic use have been reported; however, the mechanisms behind these benefits are poorly understood. The effects of a probiotic formulation (MegaDuo™) containing Bacillus coagulans SC208 and Bacillus subtilis HU58 on intestinal permeability and immune markers was assessed using a combination of the in vitro gut model, the mucosal simulator of the human intestinal microbial ecosystem (M-SHIME®), and an in vitro inflammatory bowel disease-like Caco-2/THP1 co-culture model in both healthy and antibiotic-induced dysbiosis conditions. Established M-SHIME® proximal colon vessels were treated with/without clindamycin (1 week) and then with/without daily MegaDuo™ treatment (2 weeks). The mucosal and luminal microbial communities were sampled weekly. Suspensions were removed from the proximal colon vessels after 1 and 2 weeks of MegaDuo™ treatment and added to the co-culture system. Transepithelial resistance (membrane barrier function), cytokine/chemokine release, and NFκB activity were then measured. Under conditions of antibiotic-induced dysbiosis, suspensions from MegaDuo™ treated vessels showed reduced gut membrane barrier damage and decreased levels of TNFα and IL-6 compared with suspensions from untreated vessels; no appreciable differences were observed under healthy conditions. MegaDuo™ treatment had no effect on NFκB activity of THP1-Blue™ cells. The potential benefits of MegaDuo™ treatment appeared most evident after 2 weeks of treatment.

Correction: Generation and Improvement of Effector Function of a Novel Broadly Reactive and Protective Monoclonal Antibody against Pneumococcal Surface Protein A of Streptococcus pneumoniae.

[This corrects the article DOI: 10.1371/journal.pone.0154616.].

Generation and Improvement of Effector Function of a Novel Broadly Reactive and Protective Monoclonal Antibody against Pneumococcal Surface Protein A of Streptococcus pneumoniae.

A proof-of-concept study evaluating the potential of Streptococcus pneumoniae Pneumococcal Surface Protein A (PspA) as a passive immunization target was conducted. We describe the generation and isolation of several broadly reactive mouse anti-PspA monoclonal antibodies (mAbs). MAb 140H1 displayed (i) 98% strain coverage, (ii) activity in complement deposition and opsonophagocytic killing (OPK) assays, which are thought to predict the in vivo efficacy of anti-pneumococcal mAbs, (iii) efficacy in mouse sepsis models both alone and in combination with standard-of-care antibiotics, and (iv) therapeutic activity in a mouse pneumonia model. Moreover, we demonstrate that antibody engineering can significantly enhance anti-PspA mAb effector function. We believe that PspA has promising potential as a target for the therapy of invasive pneumococcal disease by mAbs, which could be used alone or in conjunction with standard-of-care antibiotics.

The transcriptional regulator Nrg1p controls Candida albicans biofilm formation and dispersion.

The ability of Candida albicans to reversibly switch morphologies is important for biofilm formation and dispersion. In this pathogen, Nrg1p functions as a key negative regulator of the yeast-to-hypha morphogenetic transition. We have previously described a genetically engineered C. albicans tet-NRG1 strain in which NRG1 expression levels can be manipulated by the presence or absence of doxycycline (DOX). Here, we have used this strain to ascertain the role of Nrg1p in regulating the different stages of the C. albicans biofilm developmental cycle. In an in vitro model of biofilm formation, the C. albicans tet-NRG1 strain was able to form mature biofilms only when DOX was present in the medium, but not in the absence of DOX, when high levels of NRG1 expression blocked the yeast-to-hypha transition. However, in a biofilm cell retention assay in which biofilms were developed with mixtures of C. albicans tet-NRG1 and SC5314 strains, tet-NRG1 yeast cells were still incorporated into the mixed biofilms, in which an intricate network of hyphae of the wild-type strain provided for biofilm structural integrity and adhesive interactions. Also, utilizing an in vitro biofilm model under conditions of flow, we demonstrated that C. albicans Nrg1p exerts an exquisite control of the dispersal process, as overexpression of NRG1 leads to increases in dispersion of yeast cells from the biofilms. Our results demonstrate that manipulation of NRG1 gene expression has a profound influence on biofilm formation and biofilm dispersal, thus identifying Nrg1p as a key regulator of the C. albicans biofilm life cycle.

YopH inhibits early pro-inflammatory cytokine responses during plague pneumonia.

BACKGROUND: Yersinia pestis is the causative agent of pneumonic plague; recently, we and others reported that during the first 24-36 hours after pulmonary infection with Y. pestis pro-inflammatory cytokine expression is undetectable in lung tissues. RESULTS: Here, we report that, intranasal infection of mice with CO92 delta yopH mutant results in an early pro-inflammatory response in the lungs characterized by an increase in the pro-inflammatory cytokines Tumor Necrosis Factor-alpha and Interleukin one-beta 24 hours post-infection. CO92 delta yopH colonizes the lung but does not disseminate to the liver or spleen and is cleared from the host within 72 hours post-infection. This is different from what is observed in a wild-type CO92 infection, where pro-inflammatory cytokine expression and immune cell infiltration into the lungs is not detectable until 36-48 h post-infection. CO92 rapidly disseminates to the liver and spleen resulting in high bacterial burdens in these tissues ultimately cumulating in death 72-94 h post-infection. Mice deficient in TNF-alpha are more susceptible to CO92 delta yopH infection with 40% of the mice succumbing to infection. CONCLUSIONS: Altogether, our results suggest that YopH can inhibit an early pro-inflammatory response in the lungs of mice and that this is an important step in the pathogenesis of infection.

Yersinia pestis CO92 delta yopH is a potent live, attenuated plague vaccine.

An in-frame deletion of the yopH gene in Yersinia pestis CO92 attenuates virulence in both bubonic and pneumonic plague models. When it is used as a live, attenuated vaccine, CO92 delta yopH provides a high degree of protection from parental and respiratory challenge with Y. pestis CO92.

Delayed inflammatory response to primary pneumonic plague occurs in both outbred and inbred mice.

Yersinia pestis is the causative agent of plague, a disease that can manifest as either bubonic or pneumonic plague. An interesting feature of plague is that it is a rapidly progressive disease, suggesting that Y. pestis either evades and/or suppresses the innate immune response to infection. Therefore, the early host response during the course of primary pneumonic plague was investigated in two mouse strains, the outbred strain CD1 and the inbred strain C57BL/6. A comparative analysis of the course of disease in these two strains of mice indicated that they are susceptible to intranasal Y. pestis CO92 infection and have similar 50% lethal doses and kinetics of infection with respect to colonization of the lung, liver, and spleen. Significantly, in both strains of mice, robust neutrophil recruitment to the lungs was not observed until 48 h after infection, suggesting that there was a delay in inflammatory cell recruitment to the site of infection. In addition, proinflammatory cytokines (interleukin-6 [IL-6], tumor necrosis factor alpha, gamma interferon, IL-12p70, monocyte chemoattractant protein 1) and chemokines (KC, MIP-2) in the bronchoalveolar lavage fluids were not readily detected until 48 h after infection, which coincided with the increase in polymorphonuclear leukocyte (PMN) recruitment to the lungs. In comparison, CD1 mice with gram-negative pneumonia caused by Klebsiella pneumoniae exhibited strong inflammatory responses early in infection, with PMNs comprising the majority of the cells in the bronchoalveolar lavage fluid 24 h postinfection, indicating that PMN recruitment to the lungs could occur earlier in this infection than in Y. pestis infection. Together, our results indicate that there is a delay in the recruitment of neutrophils to the lungs in the mouse model of primary plague pneumonia that correlates with delayed expression of proinflammatory cytokines and chemokines in both outbred and inbred mice.