A study published in “Applied and Environmental Microbiology” in January 2016: “Characterization of a highly arginolytic Streptococcus species that potently antagonizes Streptococcus mutans”, outlines how a novel Streptococcus, designated A12, is able to inhibit the growth of Streptococcus mutans, the bacteria responsible for causing tooth decaying cavities.

Streptococcus mutans

A photomicrograph of Streptococcus mutans bacteria using Gram stain technique.
Blood agar plate culture yields coccal-like morphology without chains. The S. mutans organism can cause subacute bacterial endocarditis and dental caries. Courtesy: CDC/ Dr. Richard Facklam

The metabolism by S.mutans of sucrose (the sugar found in food) into lactic acid demineralizes teeth thereby leading to decay. Sucrose is also used by S. mutans to product a sticky polysaccharide that allows the bacteria to create a biofilm that helps S.mutans stick to tooth surfaces. A “biofilm forms when bacteria adhere to surfaces in moist environments by excreting a slimy, glue-like substance.” The plaque on teeth is a biofilm.

The new Streptococcus A12 strain found by Robert Burne, Ph.D., associate dean for research and chair of the UF College of Dentistry’s department of oral biology, and Marcelle Nascimento, D.D.S., Ph.D., an associate professor in the UF College of Dentistry’s department of restorative dental sciences, fights tooth decay four ways:

  1. Metabolizes arginine in the mouth into ammonia and urea (raises pH) thereby neutralizing the acidic effect of lactic acid
  2. Interferes with the growth of S.mutans by producing hydrogen peroxide
  3. Interferes with the growth of S.mutans by producing a protease similar to Challisin (Sgc) of Streptococcus gordonii that was able to block the CSP-ComDE signaling system, which is essential for bacteriocin (antimicrobial peptides or proteins produced by bacteria) production by S. mutans
  4. Reduces S.mutans’ ability to form biofilms

What remains to be done is to understand how the A12 strain might be applied or dosed to prevent tooth decay.

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Fecal microbiota (see here for some background on microbiota) transplantation (FMT) is defined by the Fecal Transplant Foundation (FTF) as ” a procedure in which fecal matter, or stool, is collected from a tested donor, mixed with a saline or other solution, strained, and placed in a patient, by colonoscopy, endoscopy, sigmoidoscopy, or enema.”

The FTF states that the “purpose of fecal transplant is to replace good bacteria that has been killed or suppressed, usually by the use of antibiotics, causing bad bacteria, specifically Clostridium difficile, or C. diff., to over-populate the colon. This infection causes a condition called C. diff. colitis, resulting in often debilitating, sometimes fatal diarrhea.”

photomicrograph of C. difficile

C. difficile, photo courtesy Janice Carr, CDC.

Clostridium Difficile

C. diff. is a very serious infection, and the incidence is on the rise throughout the world.  The FTF states that  C. diff. “…currently causes about 250,000 hospitalizations and 14,000 deaths each year in the U.S. – have become highly resistant to treatment, leading to a 30 percent treatment failure rate in patients infected with those strains.”

The danger from C. diff. is so great that vaccines and other treatments to prevent and treat C. diff. infection are currently in development:

  • Sanofi Pasteur is ahead with a vaccine candidate in phase III.
  • Pfizer disclosed in November 2014 that it decided to halt further  recruitment and vaccination for its ongoing Phase 2 study of PF-06425090, its candidate vaccine, and “is evaluating potential next steps for the C. difficile clinical development program.”
  • Rebiotix has a microbiota suspension delivered by enema currently in a phase II study.

Fecal Transplant Not Approved by FDA

While medical journals continued to proclaim the success of FMT, in July 2013 the FDA produced a Guidance for Industry on FMT in which they stated that “…the efficacy and safety profiles of this intervention have not yet been fully evaluated in controlled clinical trials.” The FDA goes on to state that they ” …intend to exercise enforcement discretion regarding the investigational new drug (IND) requirements for the use of fecal microbiota for transplantation (FMT) to treat Clostridium difficile (C. difficile) infection not responding to standard therapies. FDA intends to exercise this discretion provided that the treating physician obtains adequate informed consent from the patient or his or her legally authorized representative for the use of FMT products. Informed consent should include, at a minimum, a statement that the use of FMT products to treat C. difficile is investigational and a discussion of its potential risks.  FDA intends to exercise this discretion on an interim basis while the agency develops appropriate policies for the study and use of FMT products under IND.”

Delivering FMT

If traditional antibiotic therapy is not working for patients with C. diff. infections,  FMT may be delivered via various methods.

tubes with FMT suspension

FMT Tubes, Photo via WikiMedia Commons

The most traditional is a suspension that must be delivered via endoscopy or by colonoscopy, sigmoidoscopy, or enema. All of these methods are relatively expensive and have their own inherent risks and must be performed in a clinic or hospital setting.

To reduce cost, risk, and patient discomfort, oral preparations in the form of a capsule have been developed. One such approach was reported in JAMA :”Stool samples were gathered from healthy adult volunteers who had been comprehensively screened for infectious diseases and avoided eating common allergens for several days before donating.  The samples were filtered, diluted, screened, placed into capsules and frozen for four weeks to enable retesting of donors for important viral infections.  On two consecutive days each participant received 15 FMT capsules, which most of them ingested within a few minutes. ” They reported that the therapy  provided “…an overall success rate of 90 percent for the study group.”


The vaccine in development from Sanofi should be able to prevent many C. diff infections when available providing those at risk are immunized. Should C. diff infection not respond to antibiotic therapy, the use of FMT seems appropriate given the generally positive success rate and few reports of adverse events.

Additional Reading

  • “How does Fecal Microbiota Transplantation work?”, OpenBiome.com; available at: http://www.openbiome.org/about-fmt/
  • “Guidance for Industry: Enforcement Policy Regarding Investigational New Drug Requirements for Use of Fecal Microbiota for Transplantation to Treat Clostridium difficile Infection Not Responsive to Standard Therapies”, July 2013; available at: here
  • Centers for Disease Control and Prevention. Investigating Clostridium difficile Infections Across the U.S.; available at: http://www.cdc.gov/features/AntibioticResistanceThreats/index.html
  • Youngster I, Russell GH, Pindar C, Ziv-Baran T, Sauk J, Hohmann EL. Oral, Capsulized, Frozen Fecal Microbiota Transplantation for Relapsing Clostridium difficile Infection. JAMA. 2014;312(17):1772-1778. doi:10.1001/jama.2014.13875.; abstract available at: http://jama.jamanetwork.com/article.aspx?articleid=1916296
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Not to get too personal on this, but those who believe vaccines cause autism need to take a step back and review their position.

“An evidence-based meta-analysis of case-control and cohort studies”,  a report from Australia published in Vaccines on May 9, 2014, that based upon a review of 10 international studies involving more than one million children, provides additional information that vaccines are not associated with autism.

Autism and its many variants are truly significant health issues but placing the blame on vaccines is evidently not the solution to preventing autism. Given the proven health outcome benefits of vaccines, the message that vaccines are not related to autism has to be spoken and reinforced by the very same people and organizations that promulgated the opposite, but now evidently,  the incorrect position.

The abstract of the article from the Vaccine website:

“We performed a meta-analysis to summarise available evidence from case-control and cohort studies on this topic (MEDLINE, PubMed, EMBASE, Google Scholar up to April, 2014). Eligible studies assessed the relationship between vaccine administration and the subsequent development of autism or autism spectrum disorders (ASD). Two reviewers extracted data on study characteristics, methods, and outcomes. Disagreement was resolved by consensus with another author.

  • Five cohort studies involving 1,256,407 children, and five case-control studies involving 9920 children were included in this analysis.
  • The cohort data revealed no relationship between vaccination and autism (OR: 0.99; 95% CI: 0.92 to 1.06) or ASD (OR: 0.91; 95% CI: 0.68 to 1.20), or MMR (OR: 0.84; 95% CI: 0.70 to 1.01), or thimerosal (OR: 1.00; 95% CI: 0.77 to 1.31), or mercury (Hg) (OR: 1.00; 95% CI: 0.93 to 1.07).
  • Similarly the case-control data found no evidence for increased risk of developing autism or ASD following MMR, Hg, or thimerosal exposure when grouped by condition (OR: 0.90, 95% CI: 0.83 to 0.98; p = 0.02) or grouped by exposure type (OR: 0.85, 95% CI: 0.76 to 0.95; p = 0.01).

Findings of this meta-analysis suggest that vaccinations are not associated with the development of autism or autism spectrum disorder. Furthermore, the components of the vaccines (thimerosal or mercury) or multiple vaccines (MMR) are not associated with the development of autism or autism spectrum disorder.”

Children are indeed society’s most precious assets and it does not serve their, their parents’, nor society’s best interests to delay or abandon critical vaccinations any longer. It would be a cruel outcome should polio or other preventable diseases of childhood  routinely included in immunizations begin to reappear (some reports are indicating such is happening), leaving behind paralyzed, ill, or dead children in the futile belief that denying immunizations prevents autism.  Focusing on immunizations does not serve the needs of those with autism or help in preventing future cases.


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