Alteration of the intestinal microbiome: fecal microbiota transplant and probiotics for Clostridium difficile and beyond

Histamine H2-Receptor Antagonists Improve Non-Steroidal Anti-Inflammatory Drug-Induced Intestinal Dysbiosis

Dysbiosis, an imbalance of intestinal flora, can cause serious conditions such as obesity, cancer, and psychoneurological disorders. One cause of dysbiosis is inflammation. Ulcerative enteritis is a side effect of non-steroidal anti-inflammatory drugs (NSAIDs). To counteract this side effect, we proposed the concurrent use of histamine H₂ receptor antagonists (H₂RA), and we examined the effect on the intestinal flora. We generated a murine model of NSAID-induced intestinal mucosal injury, and we administered oral H₂RA to the mice. We collected stool samples, compared the composition of intestinal flora using terminal restriction fragment length polymorphism, and performed organic acid analysis using high-performance liquid chromatography. The intestinal flora analysis revealed that NSAID [indomethacin (IDM)] administration increased Erysipelotrichaceae and decreased Clostridiales but that both had improved with the concurrent administration of H₂RA. Fecal levels of acetic, propionic, and n-butyric acids increased with IDM administration and decreased with the concurrent administration of H₂RA. Although in NSAID-induced gastroenteritis the proportion of intestinal microorganisms changes, leading to the deterioration of the intestinal environment, concurrent administration of H₂RA can normalize the intestinal flora.

Recent advances in the treatment of C. difficile using biotherapeutic agents

Clostridium difficile (C. difficile) is rapidly becoming one of the most prevalent health care–associated bacterial infections in the developed world. The emergence of new, more virulent strains has led to greater morbidity and resistance to standard therapies. The bacterium is readily transmitted between people where it can asymptomatically colonize the gut environment, and clinical manifestations ranging from frequent watery diarrhea to toxic megacolon can arise depending on the age of the individual or their state of gut dysbiosis. Several inexpensive approaches are shown to be effective against virulent C. difficile in research settings such as probiotics, fecal microbiota transfer and immunotherapies. This review aims to highlight the current advantages and limitations of the aforementioned approaches with an emphasis on recent studies.

Does Obesity Influence the Risk of Clostridium difficile Infection Among Patients with Ulcerative Colitis?

BACKGROUND

Patients with ulcerative colitis (UC) are at an increased risk of Clostridium difficile infection (CDI) compared with the general population. Recent data suggest that obesity also increases the risk of CDI.

AIMS

To examine whether obesity influences the risk of CDI among patients with UC.

STUDY

We conducted a retrospective cross-sectional study of UC patients seen in gastroenterology clinic between January 1, 2014, and December 31, 2015. Records were reviewed for patients with the diagnosis of UC prior to 2014, and the first diagnosis of CDI between January 1, 2014, and December 31, 2015. Using body mass index (BMI), patients were classified into underweight (BMI < 18.5), normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). Age-adjusted and multivariate logistic regression was performed including gender, tobacco use, UC disease duration, medication exposure, and vitamin D deficiency.

RESULTS

Of the 636 patients with UC, 114 (18%) were obese, 232 (36%) overweight, 274 (43%) normal weight, and 16 (2.5%) underweight. Nineteen patients (3.0%) developed CDI during the study period. CDI risk was not associated with BMI (OR 0.90, 95% CI 0.79-1.02). Compared to normal weight patients, risk of CDI was not influenced by being obese (multivariate OR 0.63, 95% CI 0.15-2.58), overweight (multivariate OR 0.33, 95% CI 0.08-1.30), or underweight (multivariate OR 2.98, 95% CI 0.45-19.83). CDI was associated with ever use of TNF therapy (multivariate OR 6.09, 95% CI 2.07-17.93) but not vedolizumab (multivariate OR 0.76, 95% CI 0.08-7.36).

CONCLUSIONS

Obesity does not appear to be associated with the risk of C. difficile infection among patients with UC.

The Mammalian Intestinal Microbiome: Composition, Interaction with the Immune System, Significance for Vaccine Efficacy, and Potential for Disease Therapy

The mammalian gut is colonized by a large variety of microbes, collectively termed ‘the microbiome’. The gut microbiome undergoes rapid changes during the first few years of life and is highly variable in adulthood depending on various factors. With the gut being the largest organ of immune responses, the composition of the microbiome of the gut has been found to be correlated with qualitative and quantitative differences of mucosal and systemic immune responses. Animal models have been very useful to unravel the relationship between gut microbiome and immune responses and for the understanding of variations of immune responses to vaccination in different childhood populations. However, the molecular mechanisms underlying optimal immune responses to infection or vaccination are not fully understood. The gut virome and gut bacteria can interact, with bacteria facilitating viral infectivity by different mechanisms. Some gut bacteria, which have a beneficial effect on increasing immune responses or by overgrowing intestinal pathogens, are considered to act as probiotics and can be used for therapeutic purposes (as in the case of fecal microbiome transplantation).

Fecal Microbiota Transplantation

Fecal microbiota transplantation (FMT) is the transfer of stool from a healthy donor into the colon of a patient whose disease is a result of an altered microbiome, with the goal of restoring the normal microbiota and thus curing the disease. The most effective and well-studied indication for FMT is recurrent Clostridium difficile infection. At this time, there is insufficient evidence to recommend FMT for other gastrointestinal diseases, but studies are under way. There is also insufficient evidence to recommend FMT for nongastrointestinal diseases at this time. The field is rapidly emerging.

Changes in Intestinal Microbiota Following Combination Therapy with Fecal Microbial Transplantation and Antibiotics for Ulcerative Colitis

BACKGROUND

Fecal microbiota transplantation (FMT) is a potential therapeutic approach to restore normal intestinal microbiota in patients with ulcerative colitis (UC), which is associated with dysbiosis; however, treatment efficacy remains unclear. Hence, we studied the impact of antibiotic pretreatment with amoxicillin, fosfomycin, and metronidazole (AFM therapy) and FMT versus AFM alone.

METHODS

AFM therapy was administered to patients for 2 weeks until 2 days before FMT. Patients' spouses or relatives were selected as donor candidates. Donor fecal samples were collected on the day of administration and transferred into the patient's colon by colonoscopy within 6 hours. Microbiome analysis was performed by 16S rRNA next-generation sequencing.

RESULTS

Patients with mild-to-severe active UC (combination-therapy group, n = 21; AFM monotherapy group, n = 20) were included. Thirty-six patients completed this assessment (combination-therapy group, n = 17; AFM monotherapy group, n = 19). A higher clinical response was observed after combination therapy compared with AFM monotherapy at 4 weeks after treatment. After the 2-week AFM therapy, the Bacteroidetes composition was nearly abolished. The Bacteroidetes proportion recovered in clinical responders at 4 weeks after FMT was not observed in the AFM monotherapy group. Persistent antimicrobial-associated dysbiosis found in the AFM monotherapy group was reversed by FMT. The recovery rate of Bacteroidetes at 4 weeks after FMT correlated with endoscopic severity.

CONCLUSIONS

FMT following antimicrobial bowel cleansing synergistically contributes to the recovery of the Bacteroidetes composition, which is associated with clinical response and UC severity. Thus, this therapeutic protocol may be useful for managing UC.

A Tetraspecific VHH-Based Neutralizing Antibody Modifies Disease Outcome in Three Animal Models of Clostridium difficile Infection

Clostridium difficile infection (CDI), a leading cause of nosocomial infection, is a serious disease in North America, Europe, and Asia. CDI varies greatly from asymptomatic carriage to life-threatening diarrhea, toxic megacolon, and toxemia. The incidence of community-acquired infection has increased due to the emergence of hypervirulent antibiotic-resistant strains. These new strains contribute to the frequent occurrence of disease relapse, complicating treatment, increasing hospital stays, and increasing morbidity and mortality among patients. Therefore, it is critical to develop new therapeutic approaches that bypass the development of antimicrobial resistance and avoid disruption of gut microflora. Here, we describe the construction of a single heteromultimeric VHH-based neutralizing agent (VNA) that targets the two primary virulence factors of Clostridium difficile, toxins A (TcdA) and B (TcdB). Designated VNA2-Tcd, this agent has subnanomolar toxin neutralization potencies for both C. difficile toxins in cell assays. When given systemically by parenteral administration, VNA2-Tcd protected against CDI in gnotobiotic piglets and mice and to a lesser extent in hamsters. Protection from CDI was also observed in gnotobiotic piglets treated by gene therapy with an adenovirus that promoted the expression of VNA2-Tcd.

Fecal transplantation indications in ulcerative colitis. Preliminary study

BACKGROUND AND AIMS

Fecal microbiota transplantation is used with success in persistent (more than two episodes) Clostridium Difficile Infection; it has also gained importance and started to be used in inflammatory bowel disease. There are theoretical arguments that justify its use in ulcerative colitis or Crohn's disease. Based on our clinical cases we tried to evaluate the indications of fecal microbiota transplantation young patients with ulcerative colitis and multiple relapses, in which biological or immunosuppressive treatment were ineffective.

METHODS

Five patients with moderate-severe ulcerative colitis or Clostridium Difficile infection who ceased to have a therapeutic response to biological therapy, were given fecal microbiota transplant as an alternative to biological therapy and/or immunosuppression. Fecal microbiota transplant was administered via colonoscopy using healthy donors from their family.

RESULTS

The results were favorable and spectacular in all patients and complete remission was achieved for at least 10 months. Clinical remission was achieved in all patients. Endoscopic appearance of ulcers in patients improved. In 2 patients the effect of the fecal microbiota transplant diminished after 10-12 months and the tendency to relapse appeared (3-4 stools/day, blood streaks present sometimes in the stool). Reintroduction of systemic therapy or immunosuppression demonstrated that patients regained the therapeutic response to these treatments, and remission was maintained.

CONCLUSION

Fecal microbiota transplantation can be used as salvage therapy in patients refractory to biological therapy, as elective therapy in clostridium difficile infection or as an alternative therapy in young patients with multiple relapses who have reservations regarding biological or immunosuppressive treatment.

Fecal microbiota transplantation: current clinical efficacy and future prospects

Fecal microbiota transplantation (FMT) has gained mainstream attention with its remarkable efficacy in treating recurrent Clostridium difficile infection (RCDI) when there are no other effective therapies. Methods of selecting donors and routes of administration vary among studies, but there are now randomized controlled trials showing efficacy of FMT in treating RCDI. Ongoing trials of FMT for other disease such as inflammatory bowel disease are underway; this therapy should not be used for these conditions unless there is strong evidence for efficacy. Long-term safety data are sorely needed, as well as clarification of regulatory concerns.

C. difficile Infection: Changing Epidemiology and Management Paradigms

The incidence of Clostridium difficile infection (CDI) has been rising in hospitals, long-term care facilities, and within the community. Cases have been more severe with more complications, deaths, and higher healthcare-associated costs. With the emergence of a hypervirulent strain of C. difficile and the increasing prevalence of community-acquired CDI among healthy patients without traditional risk factors, the epidemiology of C. difficile has been evolving. This changing epidemiology requires a change in management. Taking into account new risk factors for CDI and growing subpopulations of affected individuals, diagnostic, treatment, and prevention approaches need to be adjusted.

Can inflammatory bowel disease be permanently treated with short-term interventions on the microbiome?

Inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis, is a chronic, relapsing and remitting set of conditions characterized by an excessive inflammatory response leading to the destruction of the gastrointestinal tract. While the exact etiology of inflammatory bowel disease remains unclear, increasing evidence suggests that the human gastrointestinal microbiome plays a critical role in disease pathogenesis. Manipulation of the gut microbiome has therefore emerged as an attractive alternative for both prophylactic and therapeutic intervention against inflammation. Despite its growing popularity among patients, review of the current literature suggests that the adult microbiome is a highly stable structure resilient to short-term interventions. In fact, most evidence to date demonstrates that therapeutic agents targeting the microflora trigger rapid changes in the microbiome, which then reverts to its pre-treatment state once the therapy is completed. Based on these findings, our ability to treat inflammatory bowel disease through short-term manipulations of the human microbiome may only have a transient effect. Thus, this review is intended to highlight the use of various therapeutic options, including diet, pre- and probiotics, antibiotics and fecal microbiota transplant, to manipulate the microbiome, with specific attention to the alterations made to the microflora along with the duration of impact.

Association of Clostridium difficile infections with acid suppression medications in children

OBJECTIVE

Multiple studies have confirmed associations between acid suppression medication and Clostridium difficile infections (CDIs) in adults. Therefore, we sought to evaluate an association between acid suppression medications and CDI in children.

STUDY DESIGN

A retrospective self-controlled case series was performed utilizing billing records from the TRICARE Management Activity military health system database. Children ages 2-18 years from October 1, 2001 to July 31, 2013, who had an outpatient or inpatient record of CDI diagnosis were included. The relative incidences (RIs) of CDI or recurrent CDI were calculated comparing time periods prescribed and not prescribed proton pump inhibitors (PPIs) or histamine-2 receptor antagonists (H2RAs).

RESULTS

There were 2531 cases of CDI among 2437 patients, and 1190 (48.8%) were prescribed acid suppression medications. CDI were more likely to occur during periods when patients were prescribed a PPI (RI 2.36; 95% CI 2.22-2.52), H2RA (RI 1.95; 95% CI 1.63-2.34), or during periods while prescribed both simultaneously (RI 2.40; 95% CI 1.90-3.04). There were 265 (10.4%) cases that were classified as recurrent among 217 (8.9%) patients. Recurrent CDI also was found to be more likely during prescription periods of PPI (RI 1.74; 95% CI 1.51-2.00) and H2RA (RI 2.63; 95% CI 1.89-3.66).

CONCLUSIONS

Acid suppression medications are associated with an increased risk of CDI and recurrent CDI. Judicious use of acid suppression medication should be considered, especially among those at highest risk for CDI.

Role of stress, depression, and aging in cognitive decline and Alzheimer's disease

Late-onset Alzheimer's disease (AD) is a chronic neurodegenerative disorder and the most common cause of progressive cognitive dysfunction and dementia. Despite considerable progress in elucidating the molecular pathology of this disease, we are not yet close to unraveling its etiopathogenesis. A battery of neurotoxic modifiers may underpin neurocognitive pathology via deleterious heterogeneous pathologic impact in brain regions, including the hippocampus. Three important neurotoxic factors being addressed here include aging, stress, and depression. Unraveling "upstream pathologies" due to these disparate neurotoxic entities, vis-à-vis cognitive impairment involving hippocampal dysfunction, is of paramount importance. Persistent systemic inflammation triggers and sustains neuroinflammation. The latter targets several brain regions including the hippocampus causing upregulation of amyloid beta and neurofibrillary tangles, synaptic and neuronal degeneration, gray matter volume atrophy, and progressive cognitive decline. However, what is the fundamental source of this peripheral inflammation in aging, stress, and depression? This chapter highlights and delineates the inflammatory involvement-i.e., from its inception from gut to systemic inflammation to neuroinflammation. It highlights an upregulated cascade in which gut-microbiota-related dysbiosis generates lipopolysaccharides (LPS), which enhances inflammation and gut's leakiness, and through a Web of interactions, it induces stress and depression. This may increase neuronal dysfunction and apoptosis, promote learning and memory impairment, and enhance vulnerability to cognitive decline.

Potential role of gastrointestinal microbiota composition in prostate cancer risk

Background

Among men in the U.S., prostate cancer is the most common cancer and the second leading cause of cancer death. Despite its prevalence, there are few established risk factors for prostate cancer. Some studies have found that intake of certain foods/nutrients may be associated with prostate cancer risk, but few have accounted for how intake and metabolic factors may interact to influence bioavailable nutrient levels and subsequent disease risk.

Presentation of the hypothesis

The composition of the gastrointestinal (GI) microbiome may influence metabolism of dietary compounds and nutrients (e.g., plant phenols, calcium, choline) that may be relevant to prostate cancer risk. We, therefore, propose the hypothesis that GI microbiota may have a markedly different composition among individuals with higher prostate cancer risk. These individuals could have microbial profiles that are conducive to intestinal inflammation and/or are less favorable for the metabolism and uptake of chemopreventive agents.

Testing the hypothesis

Because very little preliminary data exist on this potential association, a case–control study may provide valuable information on this topic. Such a study could evaluate whether the GI microbial profile is markedly different between three groups of individuals: healthy men, those with latent prostate cancer, and those with invasive prostate cancer. Any findings could then be validated in a larger study, designed to collect a series of specimens over time.

Implications of the hypothesis

Given the plethora of information emerging from the Human Microbiome Project, this is an opportune time to explore associations between the microbiome and complex human diseases. Identification of profiles that alter the host’s risk for disease may clarify inconsistencies in the literature on dietary factors and cancer risk, and could provide valuable targets for novel cancer prevention strategies.