The diagnosis of pertussis: which method to choose?

Abstract

Despite the introduction of routine vaccination against pertussis for more than a half century, leading to a drastic decline in the number of reported cases, pertussis continues to be an important respiratory disease afflicting unvaccinated infants and previously vaccinated children as well as adults in whom immunity has waned. The diagnosis of pertussis is challenging and accurate laboratory identification of Bordetella infections remains problematic. Common laboratory diagnostic methods used for pertussis diagnosis include culture, direct-fluorescent-antibody testing (DFA), serology and polymerase chain reaction (PCR). Culture of Bordetella pertussis is highly specific but fastidious and has limited sensitivity. DFA provides a much more rapid result, but has the disadvantage of poor sensitivity and specificity. Serology is not useful in infants. In older persons, it is hampered by the limitations of paired sera and it provides mainly a retrospective diagnosis. Such limitations of conventional diagnosis testing have led to the development of PCR assays. Notwithstanding its lack of standardization, PCR has been found to be more sensitive and more specific than other methods. In this report, we aimed to review current knowledge about the available diagnostic methods and tests that accurately diagnose pertussis.

Epidemiological Aspects of Pertussis among Adults and Adolescents in a Korean Outpatient Setting: A Multicenter, PCR-Based Study

“…However, the actual incidence of B. pertussis infection may have been underestimated. Additionally, PCR testing has also a risk of false positives (22, 23). …”

Is the current pertussis incidence only the results of testing? A spatial and space-time analysis of pertussis surveillance data using cluster detection methods and geographically weighted regression modelling

“…In fully vaccinated children and adults with waning immunity, the symptoms are often mild and indistinguishable from other respiratory diseases [5]. The clinical diagnosis of pertussis is challenging, not only because symptoms are often unspecific, but also because co-infection with respiratory diseases complicates diagnosis [5,8,9]. Additionally, sensitivity and specificity of the applied laboratory tests are influenced by vaccination coverage, frequency of mild cases within the population, exposure to pertussis and age of the patient so that no single laboratory test can be considered as “gold standard” for confirming pertussis cases [10].…”

Recovery of Bordetella pertussis from PCR-Positive Nasopharyngeal Samples Is Dependent on Bacterial Load

“…Real-time PCR has become the method of choice for detection of Bordetella pertussis in nasopharyngeal (NP) samples, making culture redundant (9). However, isolation of B. pertussis is of importance for epidemiologic purposes.…”