Recent research also highlights the wide immune impact of the gut microbiome. One such example is in pneumonia, where studies show that mice with their microbiome removed become sicker and are more likely to die from pneumonia than mice with an intact microbiome ( Brown et al. 2017 ). Similarly, microbiome-disrupting broad-spectrum antibiotics prior to infection also result in worsen later pneumonia ( Robak et al. 2018 ).
In asthma, differences in the newborn gut microbiome predict which infants will later develop asthma. Specifically, lower diversity of the gut microbiome and decreased abundance of specfici genera of bacteria such as Lachnospira, Veillonella, Faecalibacterium, and Rothia were associated with increased disease risk and decreases in microbial metabolites. Intriguingly, when these microbes were transferred to mice without a microbiome, they protected these mice from developing asthma ( Arrieta et al, 2015 ). Recently this same group of researchers have also linked differences in certain intestinal fungi with asthma risk ( Arrieta et al 2018 ).