Bordetella pertussis pneumonia in adults: two case reports and diagnostic challenges

INTRODUCTION: In recent years, the number of pertussis cases has increased remarkably in our country and globally. However, the prevalence of pertussis in adolescents and adults is severely underestimated due to atypical symptoms. Here, we present two cases of pneumonia caused by Bordetella pertussis (B. pertussis) that were successfully treated, with etiologic diagnosis aided by targeted next-generation sequencing (tNGS). CASE STUDY: The first case involves a young man initially misdiagnosed with an acute attack of bronchial asthma and treated with corticosteroids therapy. The second case involves a man with hypoxemia who was co-infected with Streptococcus pneumoniae during treatment. In both cases, routine laboratory examinations for pathogen detection were negative. The bronchoalveolar lavage fluid (BALF) of patients was sent for tNGS, which identified sequence reads of B. pertussis. RESULTS: The diagnosis of the two cases was confirmed by tNGS detecting B. pertussis, and the patients showed positive results after treatment. CONCLUSIONS: Adults with B. pertussis infection serve as an important source of infection and are frequently underdiagnosed or misdiagnosed. Early diagnosis and treatment can be achieved through typical cough symptoms and molecular biology tests.