After growing research in intestinal, vaginal, pulmonary, skin, oral microbiota, it is time now to highlight the upper respiratory tract (URT) microbiota. The results of a recent clinical trial have shown that we harbor bacteria in the nose which may protect us from respiratory diseases.
The nose has its own microbiota
This is shown by the results of a study published in the famous scientific journal Cell. The initial hypothesis was taken from the life experience of the author, Pr. Sarah Lebber. Indeed, no treatment relieved her mother from headaches and chronic sinusitis; she was thus operated on. Being disappointed that no one was interested in bacteria as a therapeutic approach, Prof. Lebber conducted her own clinical trial.
The scientists compared the bacteria in the nose of 100 healthy people to those of 225 patients with chronic rhinosinusitis. Results: nearly 30 bacterial families are present in the nose. One bacterial genus seems to stand out in healthy people: Lactobacilli. They are up to 10 times more abundant in certain parts of the nose in healthy people compared to sick patients! A specific species is particularly abundant: Lactobacillus casei. Indeed, this bacterium is absent in the upper respiratory tract in nearly 40% of sick patients.
Lactobacilli, a bacterial family capable of adapting to the environment of the nose
Lactobacilli are beneficial bacteria: they are able to produce lactic acid to inhibit pathogens. Despite they are usually considered as strict anaerobic bacteria, meaning they thrive in environments free of oxygen (this is the complete opposite of the nose!), they are also aerotolerant bacteria, that have adapted to the nasal environment (more specifically L. casei). Genomic sequencing has shown the existence of genes to deal with oxidative stress, and accept oxygen. During microscopic analysis, L. casei also contains fimbriae in order to be able to adhere to the nasal mucosa and prevent its rapid elimination by the mucus.
Towards the development of a probiotic nasal spray?
The researchers wanted to study a nasal spray containing L. casei for preventing respiratory diseases caused in particular by Staphylococcus aureus, Haemophilus influenzae or Moraxella catarrhalis.
It was administered twice a day to 20 healthy volunteers for 2 weeks. The bacteria in the spray quickly colonized the nose. Although no adverse effects have been detected, the effects of the spray have not been yet scientifically measured. Future studies are to be carried out to show the effectiveness of the product. We remain alert to keep you informed of the latest news…
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