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Rhinosinusitis is a chronic infection of the nasal and paranasal mucosa whose pathophysiological mechanisms are not fully understood yet. Studies on the role of the microbiota in its onset are being developed.

Although no study has precisely determined the incidence of rhinosinusitis among ENT infections, it is estimated that between 0.5 and 5% of simple rhinopharyngitis become rhinosinusitis1 (2 to 3 bouts of rhinopharyngitis per year for adults, 6 to 8 for children), which makes it a relatively common disease. However, although certain bacteria and viruses have been clearly identified in the onset of rhinopharyngitis, the mechanisms by which rhinosinusitis appears remain poorly understood.

A microbiota still being explored

A study on the bacterial etiology of rhinosinusitis identified several bacterial profiles:

  • Haemophilus influenzae and Streptococcus pneumoniae are the most frequently encountered bacteria in acute and subacute rhinosinusitis.
  • Staphylococcus aureus, Pseudomonas aeruginosa and H. influenzae are dominant in chronic rhinosinusitis2.

Another study analyzed the composition of the sinonasal microbiota in individuals with rhinosinusitis: among the bacteria present, none seemed to clearly dominate compared to the composition in a healthy individual. The authors still identified the following common phyla: Firmicutes, Actinobacteria, and Bacteroidetes3.

The nasopharyngeal microbiota of healthy individuals has been compared to that of individuals with rhinosinusitis using samples from nasal meatus lavage4. Bacterial and fungal analysis was conducted. Qualitatively, among the phyla present, cyanobacteria were the most prevalent; two species of Pseudomonas were also found (including P. aeruginosa). Furthermore, sequencing showed the presence of Corynebacterium as well as Cryptococcus neoformans, described for the first time as a major constituent of the sinus microbiota. Immune defense mechanisms against certain bacteria seem to be the cause of rhinosinusitis.

Currently, treatment is symptomatic (analgesics, antipyretics, and decongestants)—or may involve antibiotics in the most common cases. The exploration of the nasopharyngeal microbiota and its impact on the immune system could lead to more systemic treatment for rhinosinusitis. Studies are ongoing regarding the potential use of probiotics in cases of rhinosinusitis5.


1. Wald ER. Epidemiology, pathophysiology and etiology of sinusitis. Pediatr Infect Dis. 1985;4:S51-4.
2. Fasquele D. et al. Epidémiologie des sinusites : étude de 326 prélèvements réalisés de 1993 à 1996. Médecine et Maladies Infectieuses (Elsevier), 27(8–9) p. 792-799.
3. Anderson M. et al. A systematic review of the sinonasal microbiome in chronic rhinosinusitis. Am J Rhinol Allergy. 2016;30:161-6.
4. Aurora R. et al. Contrasting the microbiomes from healthy volunteers and patients with chronic rhinosinusitis. JAMA Otolaryngol Head Neck Surg. 2013;139:1328-38.
5. Cleland EJ. Et al. Probiotic manipulation of the chronic rhinosinusitis microbiome. Int Forum Allergy Rhinol.  2014 ;4:309-14.


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