Genomic epidemiology and multilevel genome typing of Bordetella pertussis

Abstract

Bordetella pertussis is responsible for the respiratory infectious disease pertussis (or whooping cough), which causes one of the most severe diseases in infants, although it can be prevented by whole cell and acellular vaccines. The recent resurgence of pertussis is partially due to pathogen adaptation to vaccines as well as resistance to antimicrobials. Surveillance of current circulating and emerging strains is therefore vital to understand the risks they pose to public health. Although there is increased genomics based typing, a genomic nomenclature for this pathogen has not been well established. Here, we implemented the Multilevel Genome Typing (MGT) system for B. pertussis with five levels of resolution, which provide targeted typing of relevant lineages as well as discrimination of closely related strains at the finest scale. The low resolution levels can describe the distribution of alleles of major vaccine antigen genes such as ptxP, fim3, fhaB and prn as well as temporal and spatial trends within the B. pertussis global population. Mid-resolution levels enables typing of antibiotic resistant lineages and Prn deficient lineages within the ptxP3 clade. High resolution levels can capture small-scale epidemiology such as local transmission events and has comparable resolution to existing genomic methods of strain relatedness assessment. The scheme offers stable MGT type assignments aiding harmonisation of typing and communication between laboratories. The scheme is available at www.mgtdb.unsw.edu.au/pertussis/ is regularly updated from global data repositories and accepts public data submissions. The MGT scheme provides a comprehensive, robust, and scalable system for global surveillance of B. pertussis.