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Bacteria and Allergy

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1: J Allergy Clin Immunol. 2001 Oct;108(4):516-20.
Allergy development and the intestinal microflora during the first year of life. Björkstén B, Sepp E, Julge K, Voor T, Mikelsaar M.

Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden.

BACKGROUND: The intestinal microflora is a likely source for the induction of immune deviation in infancy. OBJECTIVE: The purpose of this study was to prospectively relate the intestinal microflora to allergy development in 2 countries differing with respect to the prevalence of atopic diseases. METHODS: Newborn infants were followed prospectively through the first 2 years of life in Estonia (n = 24) and Sweden (n = 20). By that age, 9 Estonian and 9 Swedish infants had developed atopic dermatitis and/or positive skin prick test results. Stool samples were obtained at 5 to 6 days and at 1, 3, 6, and 12 months, and 13 groups of aerobic and anaerobic microorganisms were cultivated through use of standard methods. RESULTS: In comparison with healthy infants, babies who developed allergy were less often colonized with enterococci during the first month of life (72% vs 96%; P <.05) and with bifidobacteria during the first year of life (17% to 39% vs 42% to 69%; P <.05). Furthermore, allergic infants had higher counts of clostridia at 3 months (median value, 10.3 vs 7.2 log(10); P <.05). The prevalence of colonization with Staphylococcus aureus was also higher at 6 months (61% vs 23%; P <.05), whereas the counts of Bacteroides were lower at 12 months (9.9 vs 10.6 log(10); P <.05). CONCLUSION: Differences in the composition of the gut flora between infants who will and infants who will not develop allergy are demonstrable before the development of any clinical manifestations of atopy. Because the observations were made in 2 countries with different standards of living, we believe that our findings could indicate a role for the intestinal microflora in the development of and protection from allergy.

PMID: 11590374 [PubMed - indexed for MEDLINE]


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1: Clin Exp Allergy. 2000 Nov;30(11):1590-6.
Microflora-associated characteristics in faeces from allergic and nonallergic infants.

Böttcher MF, Nordin EK, Sandin A, Midtvedt T, Björkstén B.

Department of Health and Environment, Division of Paediatrics, Faculty of Health Sciences, Linköping University, Linköping, Sweden.

BACKGROUND: The prevalence of allergic diseases has increased particularly over the past 30-40 years. A reduced microbial stimulation during infancy may result in a development of a disturbed balance between Th1- and Th2-like immunity. The gut flora is, quantitatively, the most important source for such stimulation. OBJECTIVE: The aim of the study was to compare the gut microbial flora in 25 allergic and 47 nonallergic 13-month-old infants (range 11-18), through analysing microflora-associated biochemical markers in faeces. METHODS: Microflora associated characteristics (MACs) were assessed by determining the concentrations of eight different short chain fatty acids and the conversion of cholesterol to coprostanol by gas chromatography. Faecal tryptic activity was analysed spectrophotometrically. RESULTS: The allergic infants had lower levels of propionic, i-butyric, butyric, i-valeric and valeric acid. In contrast, they had higher levels of the rarely detected i-caproic acid, which has been associated with the presence of Clostridium difficile. Furthermore, the allergic infants had higher relative distribution of acetic and i-caproic acid. None of the other parameters differed between the groups. CONCLUSION: The results demonstrate differences in the MACs between allergic and nonallergic infants, indicating differences in the composition of the gut flora that may disturb the development of a normal Th1-/Th2-balance in allergic children.

PMID: 11069568 [PubMed - indexed for MEDLINE


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1: Clin Exp Allergy. 2005 Dec;35(12):1511-20.
The 'microflora hypothesis' of allergic diseases. Noverr MC, Huffnagle GB.

Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109-0642, USA.

Increasingly, epidemiologic and clinical data support the hypothesis that perturbations in the gastrointestinal (GI) microbiota because of antibiotic use and dietary differences in 'industrialized' countries have disrupted the normal microbiota-mediated mechanisms of immunological tolerance in the mucosa, leading to an increase in the incidence of allergic airway disease. The data supporting this 'microflora hypothesis' includes correlations between allergic airway disease and (1) antibiotic use early in life, (2) altered fecal microbiota and (3) dietary changes over the past two decades. Our laboratory has recently demonstrated that mice can develop allergic airway responses to allergens if their endogenous microbiota is altered at the time of first allergen exposure. These experimental and clinical observations are consistent with other studies demonstrating that the endogenous microbiota plays a significant role in shaping the development of the immune system. Data are beginning to accumulate that a 'balanced' microbiota plays a positive role in maintaining mucosal immunologic tolerance long after post-natal development. Other studies have demonstrated that even small volumes delivered to the nasopharynx largely end up in the GI tract, suggesting that airway tolerance and oral tolerance may operate simultaneously. The mechanism of microbiota modulation of host immunity is not known; however, host and microbial oxylipins are one potential set of immunomodulatory molecules that may control mucosal tolerance. The cumulative data are beginning to support the notion that probiotic and prebiotic strategies be considered for patients coming off of antibiotic therapy.

PMID: 16393316 [PubMed - indexed for MEDLINE


Andrew Levin also has an interesting article about allergies and flora on his website.