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Research Article

Virulence adaption to environment promotes the age-dependent nasal colonization of Staphylococcus aureus

, , , , , , , , & show all
Pages 1402-1415 | Received 04 Feb 2022, Accepted 03 May 2022, Published online: 23 May 2022
 

ABSTRACT

Staphylococcus aureus is an important human commensal bacteria colonizing the human body, especially the nasal cavity. The nasal carriage can be a source of S. aureus bacteremia. However, the bacterial factors contributing to nasal colonization are not completely understood. By analysing S. aureus strains from the nasal cavity of the children, young adults, and seniors, we found that the low activity of the SaeRS two-component system (TCS) is an important determinant for S. aureus to colonize in seniors. The senior group isolates of S. aureus showed a rather distinct sequence type composition as compared with other age group isolates. The senior group isolates showed not only a lower gene carriage of enterotoxins a, c, and q but also lower hemolytic activity against human red blood cells. Of regulators affecting hemolysin production (i.e. agr, saeRS, rot, rsp, and sarS), only the SaeRS TCS showed an age-dependent decrease of activity. The decreased virulence and better colonization ability of the senior group isolates of S. aureus were confirmed in the mouse model. The senior group isolates showed the lowest survival and the best adhesion and colonizing ability. Also, the senior nasal secretions supported S. aureus survival better than the child and young adult nasal secretions. These results indicated that the senior nasal cavity favours colonization of S. aureus with higher adhesion and lower virulence, to which the reduced SaeRS TCS activity contributes. Taken together, our results illustrate an example of bacterial adaptation to the changing host environment.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the National Natural Science Foundation of China (grant 82072235, 81772139), the Shanghai Rising-Star Program (grant number 20QA1405900), the Shanghai Science and Technology Committee (grant number 20ZR1432800) to Q.L. and by NIH (AI143792) and the Indiana Clinical and Translational Sciences Institute to T.B., which is funded, in part by Grant Number UL1TR002529 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical, and Translational Sciences Award.