Photo Credit: Dr Microbe

The following is a summary of “Trends in commercial laboratory testing and positivity for Bordetella species in the United States, 2019 through 2023,” published in the March 2025 issue of Journal of Infectious Diseases by Isenhour et al. 

Culture, polymerase chain reaction (PCR), and serology have been used to diagnose Bordetella infections.  

Researchers conducted a retrospective study to evaluate recent trends in provider testing practices and positivity rates for B. pertussis and B. parapertussis as pertussis epidemiology evolved in the United States.  

They analyzed deidentified data from a large U.S. commercial laboratory, identifying Bordetella tests from 2019 to 2023. Monthly trends in test orders were described for culture, PCR [including non-panel B. pertussis and B. parapertussis tests and respiratory panel tests], and serology. Percent positivity was assessed for serology and PCR. Test orders and positivity rates were further analyzed by age group and geographic region of the ordering provider.  

The results showed that among 5,27,206 tests, PCR accounted for 3,16,428 (60.1%), serologic tests for 204,480 (38.8%), and cultures for 5,840 (1.1%). Most PCR tests were part of a respiratory panel (83.5%), with only 215 (0.08%) positive for B. pertussis. Non-panel PCR positivity for B. pertussis varied between 3% and 16%, B. parapertussis positivity on non-panel PCR tests increased notably in early 2023.  

Investigators concluded that while PCR and serology were favored for Bordetella diagnosis, B. pertussis positivity in respiratory panels remained low, highlighting the value of commercial laboratory data in tracking pertussis diagnostic patterns. 

Source: academic.oup.com/jid/advance-article-abstract/doi/10.1093/infdis/jiaf141/8090059