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Relative susceptibility of airway organisms to antimicrobial effects of nitric oxide
Author(s) -
Workman Alan D.,
Carey Ryan M.,
Kohanski Michael A.,
Kennedy David W.,
Palmer James N.,
Adappa Nithin D.,
Cohen Noam A.
Publication year - 2017
Publication title -
international forum of allergy and rhinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.503
H-Index - 46
eISSN - 2042-6984
pISSN - 2042-6976
DOI - 10.1002/alr.21966
Subject(s) - microbiology and biotechnology , staphylococcus aureus , pseudomonas aeruginosa , candida albicans , nitric oxide , innate immune system , antimicrobial , bacteria , immune system , medicine , pathogenic bacteria , klebsiella pneumoniae , immunology , biology , escherichia coli , biochemistry , genetics , gene , endocrinology
Background Nitric oxide (NO) is released in the airway as a critical component of innate immune defense against invading pathogenic organisms. It is well documented that bacteriostatic and bactericidal effects of NO are concentration‐dependent. However, few data exist comparing relative susceptibility of common pathogens to NO at physiologic concentrations. In this study we evaluated the effects of NO on 4 common airway bacteria and 1 fungus, and examined the potential implications of discrepancies in sensitivity. Methods Staphylococcus epidermis , Staphylococcus aureus , Klebsiella pneumoniae , Pseudomonas aeruginosa , and Candida albicans cultures were adjusted to a uniform optical density (OD) and grown in log phase at 37°C with varying concentrations of NO formed by DETA NONOate. Both OD readings and colony forming units (CFUs) were measured at varying time‐points to evaluate for inhibitory effects of NO. Results P aeruginosa and C albicans were significantly more sensitive to NO at physiologic concentrations typical of the human airway. S aureus was attenuated by NO to a lesser degree, and K pneumoniae and S epidermis were more resistant to NO at all concentrations tested. Air surface liquid from cultured human sinonasal epithelial cells had an additive effect in bacterial killing of P aeruginosa , but not in S aureus . Conclusion Common airway pathogens have varying levels of susceptibility to NO at physiologic concentrations of innate immune defense. Relative sensitivity of P aeruginosa and relative resistance of S epidermis may help explain the composition of the healthy microbiome, as well as opportunistic infection in the absence of induced NO release.