Cigarette
smoke can make MRSA bacterial strains more resistant to antibiotics, new
research from the University of Bath has shown. In addition cigarette smoke
exposure can make some strains of Staphylococcus
aureus -- a microbe present in 30-60% of the global population and
responsible for many diseases, some fatal -- more invasive and persistent,
although the effect is not universal across all strains tested.
The researchers
believe the stress cigarette smoke causes to S. aureus sparks an emergency 'SOS' response, which increases the
rate of mutation in microbial DNA, resulting in hardy and persistent variants
better able to resist antibiotics.
Previous
studies had attributed smokers' increased susceptibility to infection to the
damaging effects of smoke on our immune system, but this study shows that it
may also be changing the DNA and characteristics of pathogenic microbes as
well.
In a
series of lab-based experiments the researchers exposed six reference strains
of the most important 'superbug' Methicillin- Resistant S. aureus (MRSA) clones
to cigarette smoke.
The
study links these changes to the emergence of Small Colony Variants (SCVs) --
hardy sub-populations that are adapted to harsh conditions. SCVs have been
linked to chronic infections in smokers in previous research.
The
scientists are now interested in studying how air pollution, from diesel
exhaust fumes and other sources, might affect the microbes in our nasal
passages as many of the pollution compounds are the same as in cigarette smoke.
See:
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology
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