Cessation from smoking improves innate host defense and clearance of experimentally inoculated nasal S. aureus

• Published in: The Journal of immunology (1950) 2018-05, Vol.200 (1_Supplement), p.166-166.9
• Main Authors: Cole, Alexander M., Schmidt-Owens, Mary, Beavis, Ashley C., Chong, Christine, Tarwater, Patrick M., Schaus, James, Deichen, Michael G., Cole, Amy Liese
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.200.Supp.166.9

Staphylococcus aureus (SA) nasal carriage is transient in most humans and usually benign, but dissemination of SA to extranasal sites causes the majority of clinical infections, and SA is a major cause of serious infections in the U.S. A better understanding of innate nasal decolonization mechanisms is urgently needed, as are relevant models for studying SA clearance. Here, we screened a population of healthy smokers for nasal SA carriage, and compared participants’ abilities to clear experimentally applied nasal SA before and after completion of a smoking cessation program. We determined that cigarette smoking increases mean nasal SA load (2.6×104 CFU/swab) compared to healthy non-smokers (1.7×103 CFU/swab) and might increase the rate of SA nasal carriage in otherwise healthy adults: 22 of 99 smokers carried SA at the screening visit, while only 4 of 30 non-smokers screened positive during the same time period. Only 6 of 19 experimental inoculation studies in active smokers resulted in SA clearance within the month of follow-up, while in the cessation group, 6 of 9 subjects cleared nasal SA and carriage duration averaged 21±4 days. Smoking cessation associated with enhanced expression of SA-associated IL-1β and G-CSF in nasal fluids. Participants who failed to clear SA exhibited higher nasal SA load and elevated nasal interleukin-1 receptor antagonist (IL-1RA) expression at the pre-experiment study visits. We conclude that smokers exhibit higher SA load than non-smokers, and that innate immune pathways including G-CSF expression and signaling through the IL-1 axis are important mediators of nasal SA clearance.