What do hot tubs and chest infections have in common?
New research suggests that bacteria which hang around in dirty hot tubs can determine how well your body responds to antibiotics for chest infections.
For most people, a chest infection is a temporary nuisance, making you feel rotten for a few days. The effect is unpleasant but quick, usually clearing up several days after the original infection. However, for people with lung disease, a chest infection can linger for much longer, causing incessant coughing and making life miserable for weeks on end.
Different types of disease-causing organisms (pathogens) can cause chest infections. If you have a chest infection, at one time your doctor may have prescribed antibiotics to try and get rid of it. Antibiotics are useful against some serious chest infections caused by bacteria, but there is a growing problem in their use for tackling infection — antibiotic resistance.
Bacteria have the unusual ability to acquire new genetic information from external sources, through a process called horizontal gene transfer. This enables bacteria to get the genes which can help them bypass the effects of antibiotics, which makes it harder to use them to treat infections. This can spread rapidly between bacteria, enabling resistant strains to emerge quickly.
To make matters worse, the last time a new class of antibiotics was discovered was in the 1980s. We have very few antibiotics which can replace the ones that bacteria are becoming resistant to.
Therefore, we have a twofold problem — how do you conserve the precious medicines we already have, whilst developing new treatments which are effective against the infection?
The answer may lie with Pseudomonas aeruginosa, a hardy and unpleasant bacterium which not only causes chest infections, but also septic shock and even “hot tub folliculitis” — a skin condition which you get from staying too long in dirty hot tubs.
Pseudomonas aeruginosa is the most common cause of chest infection in people with chronic lung disease. It is challenging to treat, as it is already resistant to many different types of antibiotics currently used for chest infections. But researchers think that they now know why some people respond better to antibiotic treatment than others.
Professor James Chalmers, GSK/BLF Professor of Respiratory Research at the University of Dundee, explains:
“When you have a lung condition, you become a walking target for pathogens. This is especially true for people with bronchiectasis, a lung disease where the lungs retain the mucus that normally clears these pathogens away, giving them a ready-made environment for these pathogens to spread. People with bronchiectasis and other chronic lung diseases are much more susceptible to the effects of infection.”
“We have an antibiotic called aztreonam which works against chest infections and pneumonia, but what was always a mystery was that the antibiotic would work better in some patients, despite them having infections with the same strain of Pseudomonas and having the same damage to their lungs from bronchiectasis.”
“We designed a randomised trial where we gave some patients with bronchiectasis the antibiotic and some with the placebo, but we also measured the amount of bacteria in their lungs and compared both groups.
“We found that people with much higher amounts of Pseudomonas bacterium in their lungs responded far better to antibiotic treatment than those with lower amounts. ”
So could this be a turning point in the fight against antibiotic resistance? Professor Chalmers adds:
“Although we need to test this result to see if it applies to other types of bacteria and organs in the body, we believe that this is the first described instance of a person’s response to antibiotic being affected by the amount of bacteria present in the body.
“Crucially, it gives us a much clearer view on which patients would benefit the most from antibiotic treatment. Bacterial load within the lung is generally stable over time, so this gives us something that we can test for and use when prescribing antibiotic treatment for patients.
“With more and more antibiotics being diminished by the spread of resistant bacterial strains, targeting antibiotic treatment is more essential than ever before. These results offer hope that we can conserve antibiotics for years to come, whilst we look for new treatments.”
This research was published in the American Journal of Critical Care Medicine.
