New molecular techniques have identifi ed a wide range
of bacteria that cannot be identifi ed with standard culture
and these are likely to revolutionise our understanding of
the role of micro-organisms in the pathogenesis of
diseases such as COPD. Results from studies have shown
that the lower respiratory tract is colonised by a
microbiome even in healthy individuals. One study98
reported that COPD is not associated with an alteration
of the respiratory microbiome, whereas others99,100 have
reported changes in relative abundance of specifi c
microbial phyla and in microbial diversity, and inhaled
corticosteroid use alters the microbiome in patients with
COPD.101 These fi ndings might be relevant to the eff ects
of inhaled corticosteroid on exacerbations and
pneumonia, and future studies are likely to yield further
insights into the eff ects of inhaled corticosteroids on the
respiratory microbiome.102