Staphylococcus aureus colonization in the pharynx and nasal cavity: why are some people more susceptible?

Staphylococcus aureus is one of the most important pathogenic bacteria in humans. The nose and pharynx constitute two fundamental ecological niches for this bacterium, supporting the asymptomatic carrier state and acting as sources of infection in susceptible organisms. Colonization dynamics depend on the balance between the bacteria's virulence factors, the host's immune response, and the environment. Colonization is favored by attenuated immune responses, with evidence of partial tolerance and low protective antibody titers. Colonization also appears to depend on the microbiome of the colonized site. Genetic, metabolic, lifestyle, and age factors of the host may also contribute to colonization. Global prevalence rates vary widely depending on the geographic, social, and economic context. Recently, emerging strategies such as the use of phages, microbiome modulation, nanoparticles, gene editing technologies, and vaccines have been developed as promising alternatives to prevent colonization and infection by this bacterium. This review summarizes the current evidence on the factors that allow nasal and pharyngeal colonization of S. aureus, as well as therapeutic perspectives to prevent colonization by this bacterium.