The epidemic of erythromycin-resistant Bordetella pertussis with limited genome variation associated with pertussis resurgence in China

The resurgence of Bordetella pertussis infections leading to whooping cough is a concern in many parts of the world. The number of pertussis cases in China has increased significantly since 2013. In this study, whole-genome sequencing analysis was performed for 388 B. pertussis strains isolated in China from the 1970s to 2018, combining 594 published strains from around the world. This study revealed that lineage V diverged about 50 years ago in China, while lineage IV is dominant in the other countries. It also revealed that the erythromycin-resistant sub-lineages Va, Vb, and Vc with limited genomic variation emerged 11 ~ 12 years ago. These three sub-lineages were identified after the co-purified acellular vaccines (cp-ACVs) completely replaced the previous whole cell vaccines (WCVs) after the national immunization program of 2012. It suggests that the cp-ACVs cannot induce immunity that is potent enough to restrict the spread of the lineage V, antibiotic abuse further favors the spread of this lineage in China. These findings demand a reassessment of the immunization strategy and development of new vaccines in China to stop the resurgence and drug resistance of B. pertussis.