Effects of nasopharyngeal microbiota in respiratory infections and allergies

Abstract

The human microbiome, which consists of a collective cluster of commensal, symbiotic, and pathogenic microorganisms living in the human body, plays a key role in host health and immunity. The human nasal cavity harbors commensal bacteria that suppress the colonization of opportunistic pathogens. However, dysbiosis of the nasal microbial community is associated with many diseases, such as acute respiratory infections including otitis media, sinusitis and bronchitis and allergic respiratory diseases including asthma. The nasopharyngeal acquisition of pneumococcus, which exists as a pathobiont in the nasal cavity, is the initial step in virtually all pneumococcal diseases. Although the factors influencing nasal colonization and elimination are not fully understood, the adhesion of opportunistic pathogens to nasopharyngeal mucosa receptors and the eliciting of immune responses in the host are implicated in addition to bacterial microbiota properties and colonization resistance dynamics. Probiotics or synbiotic interventions may show promising and effective roles in the adjunctive treatment of dysbiosis; however, more studies are needed to characterize how these interventions can be applied in clinical practice in the future.

Keywords: Microbiota; Nasopharynx; Opportunistic infections; Pneumococcus; Respiratory tract infections.

Fig. 1.

Diversity of the microbiome in symbiosis and dysbiosis. Delivery type, environmental conditions, socioeconomic conditions, and genetic background are factors that shape the nasopharyngeal microbiome of children. However, diseases such as allergic rhinitis, environmental hazards, and antibiotic usage can lead to dysbiosis, resulting in pathogen overgrowth, which may lead to recurrent infections.