31 May, 2006
Implantation of Bacteroides assisted by Methanobrevibacter smithii.
(This was sent to me by Kevin and it could have significant implications for attempts to implant Bacteroides, which normally makes up 30-50% of the bacteria in the bowel and which seems to have a controlling role. It has been shown to be able to displace Clostridium dificile, a major cause of post-antibiotic diarrhoea.)
Please see:http://www.nature.com/news/2006/060522/full/060522-19.htmlA recent study in mice has highlighted the importance of methanogenic bacteria in the intestines for efficient digestion of food. The mouse model system used is rather artificial, but could have implications for obesity.Samuel Buck of Washington University in St Louis, Missouri presented the results at the American Society for Microbiology meeting in Orlando, and will publish them shortly in the Proceedings of the National Academy of Sciences.Paraphrasing from the article:"The researchers took mice that had been grown in a sterile environment, with no microbes in their guts, and injected them with a very common strain of human intestinal bacteria, called Bacteroides thetaiotaomicron. Some of the mice also received a dose of of Methanobrevibacter smithii, which is effectively a waste-removal bug. M. smithii acts by clearing waste products and hydrogen produced by other bacteria, and so helps other gut bacteria digest some of the fibrous components of food that we cannot, and turn them into material that our bodies can use. Without these bugs, waste accumulates and blocks the activity of other gut bacteria.About 100 times more microorganisms took up residence in the colon of mice injected with both B. theta and M. smithii than in those injected with B. theta alone. This suggests that the presence of waste-removing M. smithii was somehow helping other bacteria to thrive. The researchers found that mice with a hefty dose of M. smithii in their guts are fatter than those that don't have the bacteria".
(This was sent to me by Kevin and it could have significant implications for attempts to implant Bacteroides, which normally makes up 30-50% of the bacteria in the bowel and which seems to have a controlling role. It has been shown to be able to displace Clostridium dificile, a major cause of post-antibiotic diarrhoea.)
Please see:http://www.nature.com/news/2006/060522/full/060522-19.htmlA recent study in mice has highlighted the importance of methanogenic bacteria in the intestines for efficient digestion of food. The mouse model system used is rather artificial, but could have implications for obesity.Samuel Buck of Washington University in St Louis, Missouri presented the results at the American Society for Microbiology meeting in Orlando, and will publish them shortly in the Proceedings of the National Academy of Sciences.Paraphrasing from the article:"The researchers took mice that had been grown in a sterile environment, with no microbes in their guts, and injected them with a very common strain of human intestinal bacteria, called Bacteroides thetaiotaomicron. Some of the mice also received a dose of of Methanobrevibacter smithii, which is effectively a waste-removal bug. M. smithii acts by clearing waste products and hydrogen produced by other bacteria, and so helps other gut bacteria digest some of the fibrous components of food that we cannot, and turn them into material that our bodies can use. Without these bugs, waste accumulates and blocks the activity of other gut bacteria.About 100 times more microorganisms took up residence in the colon of mice injected with both B. theta and M. smithii than in those injected with B. theta alone. This suggests that the presence of waste-removing M. smithii was somehow helping other bacteria to thrive. The researchers found that mice with a hefty dose of M. smithii in their guts are fatter than those that don't have the bacteria".
09 May, 2006
Autism can be considered to be an infection.
In Clin Infect Dis. 2002 Sep 1;35(Suppl 1):S6-S16, Finegold et al report the correlation between the presence of intestinal spore-forming bacteria and late-onset autism.
"Some cases of late-onset (regressive) autism may involve abnormal flora because oral vancomycin, which is poorly absorbed, may lead to significant improvement in these children. Fecal flora of children with regressive autism was compared with that of control children, and clostridial counts were higher. The number of clostridial species found in the stools of children with autism was greater than in the stools of control children. Children with autism had 9 species of Clostridium not found in controls, whereas controls yielded only 3 species not found in children with autism. In all, there were 25 different clostridial species found. In gastric and duodenal specimens, the most striking finding was total absence of non-spore-forming anaerobes and microaerophilic bacteria from control children and significant numbers of such bacteria from children with autism. These studies demonstrate significant alterations in the upper and lower intestinal flora of children with late-onset autism and may provide insights into the nature of this disorder."
This theme is further developed in a paper entitled "Real-time PCR quantitation of clostridia in feces of autistic children.Appl Environ Microbiol. 2004 Nov;70(11):6459-65 by Song Y, Liu C and Finegold SM. They conclude the following:-
"Based on the hypothesis that intestinal clostridia play a role in late-onset autism, we have been characterizing clostridia from stools of autistic and control children. We applied the TaqMan real-time PCR procedure to detect and quantitate three Clostridium clusters and one Clostridium species, C. bolteae, in stool specimens. Group- and species-specific primers targeting the 16S rRNA genes were designed, and specificity of the primers was confirmed with DNA from related bacterial strains. In this procedure, a linear relationship exists between the threshold cycle (CT) fluorescence value and the number of bacterial cells (CFU). The assay showed high sensitivity: as few as 2 cells of members of cluster I, 6 cells of cluster XI, 4 cells of cluster XIVab, and 0.6 cell of C. bolteae could be detected per PCR. Analysis of the real-time PCR data indicated that the cell count differences between autistic and control children for C. bolteae and the following Clostridium groups were statistically significant: mean counts of C. bolteae and clusters I and XI in autistic children were 46-fold (P = 0.01), 9.0-fold (P = 0.014), and 3.5-fold (P = 0.004) greater than those in control children, respectively, but not for cluster XIVab (2.6 x 10(8) CFU/g in autistic children and 4.8 x 10(8) CFU/g in controls; respectively). More subjects need to be studied. The assay is a rapid and reliable method, and it should have great potential for quantitation of other bacteria in the intestinal tract."
Another paper by Parracho HM, Bingham MO, Gibson GR, McCartney AL entitled "Differences between the gut microflora of children with autistic spectrum disorders and that of healthy children." has been published in J Med Microbiol. 2005 Oct;54(Pt 10):987-91.
The abstract reads "Children with autistic spectrum disorders (ASDs) tend to suffer from severe gastrointestinal problems. Such symptoms may be due to a disruption of the indigenous gut flora promoting the overgrowth of potentially pathogenic micro-organisms. The faecal flora of patients with ASDs was studied and compared with those of two control groups (healthy siblings and unrelated healthy children). Faecal bacterial populations were assessed through the use of a culture-independent technique, fluorescence in situ hybridization, using oligonucleotide probes targeting predominant components of the gut flora. The faecal flora of ASD patients contained a higher incidence of the Clostridium histolyticum group (Clostridium clusters I and II) of bacteria than that of healthy children. However, the non-autistic sibling group had an intermediate level of the C. histolyticum group, which was not significantly different from either of the other subject groups. Members of the C. histolyticum group are recognized toxin-producers and may contribute towards gut dysfunction, with their metabolic products also exerting systemic effects. Strategies to reduce clostridial population levels harboured by ASD patients or to improve their gut microflora profile through dietary modulation may help to alleviate gut disorders common in such patients."
Read more at http://www.neurotransmitter.net/autismclostridia.html or by putting "clostridia +autism" into Google.
In Clin Infect Dis. 2002 Sep 1;35(Suppl 1):S6-S16, Finegold et al report the correlation between the presence of intestinal spore-forming bacteria and late-onset autism.
"Some cases of late-onset (regressive) autism may involve abnormal flora because oral vancomycin, which is poorly absorbed, may lead to significant improvement in these children. Fecal flora of children with regressive autism was compared with that of control children, and clostridial counts were higher. The number of clostridial species found in the stools of children with autism was greater than in the stools of control children. Children with autism had 9 species of Clostridium not found in controls, whereas controls yielded only 3 species not found in children with autism. In all, there were 25 different clostridial species found. In gastric and duodenal specimens, the most striking finding was total absence of non-spore-forming anaerobes and microaerophilic bacteria from control children and significant numbers of such bacteria from children with autism. These studies demonstrate significant alterations in the upper and lower intestinal flora of children with late-onset autism and may provide insights into the nature of this disorder."
This theme is further developed in a paper entitled "Real-time PCR quantitation of clostridia in feces of autistic children.Appl Environ Microbiol. 2004 Nov;70(11):6459-65 by Song Y, Liu C and Finegold SM. They conclude the following:-
"Based on the hypothesis that intestinal clostridia play a role in late-onset autism, we have been characterizing clostridia from stools of autistic and control children. We applied the TaqMan real-time PCR procedure to detect and quantitate three Clostridium clusters and one Clostridium species, C. bolteae, in stool specimens. Group- and species-specific primers targeting the 16S rRNA genes were designed, and specificity of the primers was confirmed with DNA from related bacterial strains. In this procedure, a linear relationship exists between the threshold cycle (CT) fluorescence value and the number of bacterial cells (CFU). The assay showed high sensitivity: as few as 2 cells of members of cluster I, 6 cells of cluster XI, 4 cells of cluster XIVab, and 0.6 cell of C. bolteae could be detected per PCR. Analysis of the real-time PCR data indicated that the cell count differences between autistic and control children for C. bolteae and the following Clostridium groups were statistically significant: mean counts of C. bolteae and clusters I and XI in autistic children were 46-fold (P = 0.01), 9.0-fold (P = 0.014), and 3.5-fold (P = 0.004) greater than those in control children, respectively, but not for cluster XIVab (2.6 x 10(8) CFU/g in autistic children and 4.8 x 10(8) CFU/g in controls; respectively). More subjects need to be studied. The assay is a rapid and reliable method, and it should have great potential for quantitation of other bacteria in the intestinal tract."
Another paper by Parracho HM, Bingham MO, Gibson GR, McCartney AL entitled "Differences between the gut microflora of children with autistic spectrum disorders and that of healthy children." has been published in J Med Microbiol. 2005 Oct;54(Pt 10):987-91.
The abstract reads "Children with autistic spectrum disorders (ASDs) tend to suffer from severe gastrointestinal problems. Such symptoms may be due to a disruption of the indigenous gut flora promoting the overgrowth of potentially pathogenic micro-organisms. The faecal flora of patients with ASDs was studied and compared with those of two control groups (healthy siblings and unrelated healthy children). Faecal bacterial populations were assessed through the use of a culture-independent technique, fluorescence in situ hybridization, using oligonucleotide probes targeting predominant components of the gut flora. The faecal flora of ASD patients contained a higher incidence of the Clostridium histolyticum group (Clostridium clusters I and II) of bacteria than that of healthy children. However, the non-autistic sibling group had an intermediate level of the C. histolyticum group, which was not significantly different from either of the other subject groups. Members of the C. histolyticum group are recognized toxin-producers and may contribute towards gut dysfunction, with their metabolic products also exerting systemic effects. Strategies to reduce clostridial population levels harboured by ASD patients or to improve their gut microflora profile through dietary modulation may help to alleviate gut disorders common in such patients."
Read more at http://www.neurotransmitter.net/autismclostridia.html or by putting "clostridia +autism" into Google.
