Previous studies have shown a higher probability of a fatal outcome in individuals colonized with Staphylococcus aureus. However, a similar trend was observed only in the confirmed case of repeated S. aureus infection. Therefore, although it is generally believed that colonization of the nasopharynx with Staphylococcus aureus increases the risk of developing an infectious disease and death, its role as an independent risk factor for the development of a fatal outcome in patients infected is not yet known.

In a meta-analysis by a team of researchers led by Marin Schweizer (Department of Internal Medicine, University of Iowa, USA), 140 abstracts and 36 full-text articles were analyzed, and data from 8 studies have analyzed the relationship between nasopharyngeal colonization with Staphylococcus aureus and mortality indicators in infected patients. In one of the studies, the population studied consisted of newborns in the intensive care units of the neonatal service.

No association was found between colonization of the nasopharynx S. aureus and the probability of developing a fatal outcome (combined odds ratio (OR)) 1.25, 95% CI 0.43-3 , 66; n = 8; heterogeneity P = 0.002). An interesting conclusion was drawn from a targeted analysis of deaths, which demonstrated the "protective effect" of nasopharyngeal colonization with Staphylococcus aureus, which was expressed in a reduced probability of a fatal outcome (OSH 0.42 , 95% CI 0.10-1.84; n = 3; heterogeneity P = 0.14).

In one of the studies, to which the researchers referred in the process of formulating the conclusions, it was shown that the probability of a fatal outcome in the event of colonization of the nasopharynx by Staphylococcus aureus is much lower than that of general population. According to the researchers, one of the possible explanations for this fact is a more pronounced immunity which existed in this category of patients even before the development of an infectious disease. On the other hand, the possibility of a less invasive capacity of the colonizing strains of Staphylococcus aureus is not excluded.

A significant advantage of this meta-analysis is the inclusion of heterogeneous patient populations.

We know that the severity of immunity varies with age. Therefore, age-related characteristics should be taken into account in relation to any questionable facts obtained during the study which are likely to affect its results. An increased risk of death among carriers of Staphylococcus aureus in the nasopharynx requires further study, as well as the development of means to prevent it.