Funding: this study was conducted as part of two projects: The Study of the Role of Microbial Communities in Human Oropharynx and Blood in Diphtheria, Pertussis and Other Infectious Inflammatory Diseases (Project ID А16-116021550311-2) and The Development of Molecular-Genetic Methods for Laboratory Diagnosis of Diphtheria and Pertussis (Project ID АААА-А16-116101810127-7) supported by the Sectoral Research Program of the Russian Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Problem-oriented Research in Epidemiological Surveillance of Infectious and Parasitic Diseases in 2016-2020).

Contribution of the authors to this work:Chagina IA — analysis of literature, data collection and interpretation, drafting of a manuscript; Perevarova YuS, Perevarov VV — analysis of literature, data analysis and interpretation, drafting of a manuscript; Chaplin AV — research planning, data analysis and interpretation, drafting of a manuscript; Borisova OYu — research planning, data collection and interpretation, drafting of a manuscript; Kafarskaya LI — data interpretation, drafting of a manuscript; Afanas’ev SS, Aleshkin VA — research planning, drafting of a manuscript. All authors participated in editing of the manuscript.