Lactobacillus johnsonii ameliorates intestinal, extra-intestinal and systemic pro-inflammatory immune responses following murine Campylobacter jejuni infection

Campylobacter jejuni infections are progressively increasing worldwide. Probiotic treatment might open novel therapeutic or even prophylactic approaches to combat campylobacteriosis. In the present study secondary abiotic mice were generated by broad-spectrum antibiotic treatment and perorally reassociated with a commensal murine Lactobacillus johnsonii strain either 14 days before (i.e. prophylactic regimen) or 7 days after (i.e. therapeutic regimen) peroral C. jejuni strain 81–176 infection. Following peroral reassociation both C. jejuni and L. johnsonii were able to stably colonize the murine intestinal tract. Neither therapeutic nor prophylactic L. johnsonii application, however, could decrease intestinal C. jejuni burdens. Notably, C. jejuni induced colonic apoptosis could be ameliorated by prophylactic L. johnsonii treatment, whereas co-administration of L. johnsonii impacted adaptive (i.e. T and B lymphocytes, regulatory T cells), but not innate (i.e. macrophages and monocytes) immune cell responses in the intestinal tract. Strikingly, C. jejuni induced intestinal, extra-intestinal and systemic secretion of pro-inflammatory mediators (such as IL-6, MCP-1, TNF and nitric oxide) could be alleviated by peroral L. johnsonii challenge. In conclusion, immunomodulatory probiotic species might offer valuable strategies for prophylaxis and/or treatment of C. jejuni induced intestinal, extra- intestinal as well as systemic pro-inflammatory immune responses in vivo

The Probiotic Compound VSL#3 Modulates Mucosal, Peripheral, and Systemic Immunity Following Murine Broad-Spectrum Antibiotic Treatment

There is compelling evidence linking the commensal intestinal microbiota with host health and, in turn, antibiotic induced perturbations of microbiota composition with distinct pathologies. Despite the attractiveness of probiotic therapy as a tool to beneficially alter the intestinal microbiota, its immunological effects are still incompletely understood. The aim of the present study was to assess the efficacy of the probiotic formulation VSL#3 consisting of eight distinct bacterial species (including Streptococcus thermophilus, Bifidobacterium breve, B. longum, B. infantis, Lactobacillus acidophilus, L. plantarum, L. paracasei, and L. delbrueckii subsp. Bulgaricus) in reversing immunological effects of microbiota depletion as compared to reassociation with a complex murine microbiota. To address this, conventional mice were subjected to broad-spectrum antibiotic therapy for 8 weeks and perorally reassociated with either VSL#3 bacteria or a complex murine microbiota. VSL#3 recolonization resulted in restored CD4+ and CD8+ cell numbers in the small and large intestinal lamina propria as well as in B220+ cell numbers in the former, whereas probiotic intervention was not sufficient to reverse the antibiotic induced changes of respective cell populations in the spleen. However, VSL#3 application was as efficient as complex microbiota reassociation to attenuate the frequencies of regulatory T cells, activated dendritic cells and memory/effector T cells in the small intestine, colon, mesenteric lymph nodes, and spleen. Whereas broad-spectrum antibiotic treatment resulted in decreased production of cytokines such as IFN-γ, IL-17, IL-22, and IL-10 by CD4+ cells in respective immunological compartments, VSL#3 recolonization was sufficient to completely recover the expression of the anti-inflammatory cytokine IL-10 without affecting pro-inflammatory mediators. In summary, the probiotic compound VSL#3 has an extensive impact on mucosal, peripheral, and systemic innate as well as adaptive immunity, exerting beneficial anti-inflammatory effects in intestinal as well as systemic compartments. Hence, VSL#3 might be considered a therapeutic immunomodulatory tool following antibiotic therapy

Prevalence and antimicrobial susceptibility of Arcobacter species in human stool samples derived from out- and inpatients: the prospective German Arcobacter prevalence study Arcopath

Background: Arcobacter species, particularly A. butzleri, but also A. cryaerophilus constitute emerging pathogens causing gastroenteritis in humans. However, isolation of Arcobacter may often fail during routine diagnostic procedures due to the lack of standard protocols. Furthermore, defined breakpoints for the interpretation of antimicrobial susceptibilities of Arcobacter are missing. Hence, reliable epidemiological data of human Arcobacter infections are scarce and lacking for Germany. We therefore performed a 13-month prospective Arcobacter prevalence study in German patients. Results: A total of 4636 human stool samples was included and Arcobacter spp. were identified from 0.85% of specimens in 3884 outpatients and from 0.40% of specimens in 752 hospitalized patients. Overall, A. butzleri was the most prevalent species (n = 24; 67%), followed by A. cryaerophilus (n = 10; 28%) and A. lanthieri (n = 2; 6%). Whereas A. butzleri, A. cryaerophilus and A. lanthieri were identified in outpatients, only A. butzleri could be isolated from samples of hospitalized patients. Antimicrobial susceptibility testing of Arcobacter isolates revealed high susceptibilities to ciprofloxacin, whereas bimodal distributions of MICs were observed for azithromycin and ampicillin. Conclusions: In summary, Arcobacter including A. butzleri, A. cryaerophilus and A. lanthieri could be isolated in 0.85% of German outpatients and ciprofloxacin rather than other antibiotics might be appropriate for antibiotic treatment of infections. Further epidemiological studies are needed, however, to provide a sufficient risk assessment of Arcobacter infections in humans

Dissecting the interplay between intestinal microbiota and host immunity in health and disease: Lessons learned from germfree and gnotobiotic animal models

This review elaborates the development of germfree and gnotobiotic animal models and their application in the scientific field to unravel mechanisms underlying host–microbe interactions and distinct diseases. Strictly germfree animals are raised in isolators and not colonized by any organism at all. The germfree state is continuously maintained by birth, raising, housing and breeding under strict sterile conditions. However, isolator raised germfree mice are exposed to a stressful environment and exert an underdeveloped immune system. To circumvent these physiological disadvantages depletion of the bacterial microbiota in conventionally raised and housed mice by antibiotic treatment has become an alternative approach. While fungi and parasites are not affected by antibiosis, the bacterial microbiota in these “secondary abiotic mice” have been shown to be virtually eradicated. Recolonization of isolator raised germfree animals or secondary abiotic mice results in a gnotobiotic state. Both, germfree and gnotobiotic mice have been successfully used to investigate biological functions of the conventional microbiota in health and disease. Particularly for the development of novel clinical applications germfree mice are widely used tools, as summarized in this review further focusing on the modulation of bacterial microbiota in laboratory mice to better mimic conditions in the human host

Peroral low-dose Toxoplasma gondii infection of human microbiota-associated mice — a subacute ileitis model to unravel pathogen–host interactions

Within 1 week following high-dose Toxoplasma gondii infection, mice develop lethal necrotizing ileitis. However, data from a subacute T. gondii-induced ileitis model are scarce. Therefore, mice harboring a human gut microbiota were perorally infected with one cyst of T. gondii. Within 9 days post-infection, the intestinal microbiota composition shifted towards higher loads of commensal enterobacteria and enterococci. Following T. gondii infection, mice were clinically only mildly affected, whereas ≈60% of mice displayed fecal blood and mild-to-moderate ileal histopathological changes. Intestinal inflammation was further characterized by increased apoptotic intestinal epithelial cells, which were accompanied by elevated proliferating gut epithelial cell numbers. As compared to naive controls, infected mice displayed elevated numbers of intestinal T lymphocytes and regulatory T-cells and increased pro-inflammatory mediator secretion. Remarkably, T. gondii-induced apoptotic and pro-inflammatory immune responses were not restricted to the gut, but could also be observed in extra-intestinal compartments including kidney, liver, and lung. Strikingly, low-dose T. gondii infection resulted in increased serum levels of pro- and anti-inflammatory cytokines. In conclusion, the here presented subacute ileitis model following peroral low-dose T. gondii infection of humanized mice allows for detailed investigations of the molecular mechanism underlying the “ménage à trois” of pathogens, human gut microbiota, and immunity

Lactobacillus johnsonii ameliorates intestinal, extra-intestinal and systemic pro-inflammatory immune responses following murine Campylobacter jejuni infection

AbstractCampylobacter jejuni infections are progressively increasing worldwide. Probiotic treatment might open novel therapeutic or even prophylactic approaches to combat campylobacteriosis. In the present study secondary abiotic mice were generated by broad-spectrum antibiotic treatment and perorally reassociated with a commensal murine Lactobacillus johnsonii strain either 14 days before (i.e. prophylactic regimen) or 7 days after (i.e. therapeutic regimen) peroral C. jejuni strain 81–176 infection. Following peroral reassociation both C. jejuni and L. johnsonii were able to stably colonize the murine intestinal tract. Neither therapeutic nor prophylactic L. johnsonii application, however, could decrease intestinal C. jejuni burdens. Notably, C. jejuni induced colonic apoptosis could be ameliorated by prophylactic L. johnsonii treatment, whereas co-administration of L. johnsonii impacted adaptive (i.e. T and B lymphocytes, regulatory T cells), but not innate (i.e. macrophages and monocytes) immune cell responses in the intestinal tract. Strikingly, C. jejuni induced intestinal, extra-intestinal and systemic secretion of pro-inflammatory mediators (such as IL-6, MCP-1, TNF and nitric oxide) could be alleviated by peroral L. johnsonii challenge. In conclusion, immunomodulatory probiotic species might offer valuable strategies for prophylaxis and/or treatment of C. jejuni induced intestinal, extra-intestinal as well as systemic pro-inflammatory immune responses in vivo.</jats:p

Amelioration of intestinal and systemic sequelae of murine Campylobacter jejuni infection by probiotic VSL#3 treatment

Abstract Background The incidence of human Campylobacter jejuni infections is progressively increasing worldwide. Probiotic compounds might open up valuable tools to decrease pathogen burden and subsequent pro-inflammatory immune responses, but in vivo data are scarce. Methods and results Secondary abiotic mice generated by broad-spectrum antibiotic treatment were perorally challenged with the commercial probiotic compound VSL#3 consisting of Streptococcus thermophilus, Bifidobacterium breve, Bifidobacterium longum, Bifidobacterium infantis, Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus paracasei, and Lactobacillus delbrueckii ssp. bulgaricus) either 5 days before (i.e. prophylactic regimen) or after (i.e. therapeutic regimen) peroral C. jejuni strain 81–176 infection, and analyzed 3 weeks following the initial bacterial re-association. Upon challenge, mice were colonized with the probiotic bacteria and/or C. jejuni at comparable intestinal loads, but co-colonization did not result in reduction of the pathogen burden. Remarkably, prophylactic as well as therapeutic VSL#3 treatment of C. jejuni infected mice ameliorated intestinal apoptosis and pro-inflammatory immune responses as indicated by lower numbers of innate and adaptive immune cell populations in the murine colon upon probiotic prophylaxis or treatment and reduced colonic concentrations of pro-inflammatory mediators including IL-6 and MCP-1. Importantly, concentrations of anti-inflammatory mediators such as IL-10 were significantly elevated in the colon of probiotics treated mice as compared to untreated controls. Strikingly, prophylactic VSL#3 treatment attenuated C. jejuni induced systemic pro-inflammatory responses as indicated by less TNF and IL-12p70 secretion in the spleen of VSL#3 pre-treated as compared to non-treated mice. Conclusion Administration of probiotic formulations such as VSL#3 might open up valuable strategies for prophylaxis and/or treatment of C. jejuni induced intestinal and systemic sequelae in vivo by the suppression of pro-inflammatory and induction of anti-inflammatory responses