A Case for Antibiotic Perturbation of the Microbiota Leading to Allergy Development

Lisa A Reynolds; B Brett Finlay

Disclosures

Expert Rev Clin Immunol. 2013;9(11):1019-1030. 

In This Article

Probiotic Strategies for Allergy Prevention & Treatment

Despite the adverse effects of antibiotics on the microbiota, leading to an increased risk of allergy development, antibiotics will continue to be essential tools for controlling bacterial infections. Many studies have therefore investigated whether the use of probiotics during early life can reduce the occurrence of atopy, a strategy that could potentially mitigate the negative effects of antibiotics.

Human studies have failed to demonstrate a significant reduction in asthma onset following probiotic exposure in utero or in early life,[76] generally consisting of a mixture of Lactobacillus and Bifidobacterium species.[77–80] A more protective effect of probiotic administration, however, has been seen in murine experiments. When pregnant mice are given freeze-dried Acinetobacter lwoffii bacteria, their offspring demonstrate some protection against ovalbumin-driven airway inflammation, with reduced Th2 cell responses compared with untreated mice.[81] Additionally, oral treatment with Lactobacillus rhamnosus,[82,83]Lactobacillus reuteri,[84]Lactobacillus paracasei[85] or Bifidobacterium lactis,[82] intranasal administration of Bifidobacterium longum[86] and intragastric delivery of L. rhamnosus[87] have been associated with protection in murine allergy models. In some cases, this has been demonstrated to be dependent on the administration of live bacteria,[84] and there have been associations with induction of regulatory responses following bacteria administration,[83,85,88,89] but largely the mechanisms of protection remain unclear.

It is likely that the microbiota act co-operatively to achieve immune modulation, thus administering single species of bacteria to patients may not be the optimal strategy. Whole fecal transfers have been effective in the treatment of recurrent Clostridium difficile infections.[90] Approaches that transfer complex functioning communities are likely more stable, and have a greater ability to colonize and have a persistent effect on immune homeostasis,[91,92] in contrast to treating with a single species that needs to be repeatedly administered to confer an effect.

In humans, a number of factors, including host genetics, existing microbiota and environment will determine to what extent administered bacteria will be able to colonize, and modulate immune cell phenotypes. It is possible that the effects of probiotic administration will only be revealed in situations when severe microbial dysbiosis has occurred, and it will be interesting to focus on whether probiotics can reduce the risk of allergy onset in the context of heavy antibiotic use in early life.

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