http://www.digitaljournal.com/life/health/antibiotics-administered-early-in-life-can-affect-immunity/article/401759

Antibiotics administered early in life can affect immunity

Posted Sep 7, 2014 by Tim Sandle
Different antibiotics, taken early in life, can adversely affect the bacteria that play a positive role in promoting a healthy immune system, according to a new study.
Resistance to drugs emerges through changes in a bacterium's genetic code -- altering the targe...
Resistance to drugs emerges through changes in a bacterium's genetic code -- altering the target on its surface to which antibiotics would normally bind, making the germ impenetrable or allowing it to destroy or "spit out" the antibiotic
Jorge Dirkx, BELGA/AFP/File
Most bacteria living in the gut appear to play a positive role in promoting a healthy immune system (as recent research into the human microbiome has discovered). However, few antibiotic treatments can discriminate between beneficial bacteria and bacteria that can cause harm (the very pathogens than an antibiotic is intended to treat). For adults, in most cases, the body is sufficiently robust to deal with a loss of some 'good bacteria'. However, scientists are concerned that an over-use of antibiotics administered to new born child could lead to a loss of beneficial bacteria which, in turn, could affect how effective the child’s immune system becomes in later life.
To look at this further, an experiment was designed. For the study, the researchers tested the impact of two common antibiotics: vancomycin and streptomycin, on new-born mice. They found that streptomycin increased susceptibility in the mice to a disease known as hypersensitivity pneumonitis later in life. However, the other antibioitc - vancomycin - had no effect. The difference in each antibiotic’s long-term effects can be attributed to how they changed the bacterial ecosystem in the gut. Hypersensitivity pneumonitis is an allergic disease found in people who engage in occupations such as farming, sausage-making, and cleaning hot tubs. The experimental inference is that different antibiotics affect different gut bacteria in different way.
Despite the differences seen, the researchers stress that infants should be treated with antibiotics when needed. At the same time, the scientists hope that the results will help pinpoint which bacteria make people less susceptible to disease and the finding opens up further research opportunities to look at different antibiotics.
Moreover, developing the research could open up the possibility of boosting helpful bacteria through the use of probiotics. With this, in theory, once a doctor understands which bacteria prevent disease, it might be possible to design cultures so that children get inoculated with these types of bacteria.
The findings have been published in the Journal of Allergy and Clinical Immunology. The study is titled “Perinatal antibiotic-induced shifts in gut microbiota have differential effects on inflammatory lung diseases”.
In related research, a different research group have explored how beta-lactamase enzymes can be given orally as drugs, to protect the beneficial gut bacteria from systemic antibiotics.