Molecular detection of respiratory pathogens: Towards clinical interpretation

In up to 40 percent of the acute respiratory tract infections no pathogen is identified. In chapter 2 we describe the validation of a newly multiplex PCR for respiratory viruses. Analytical and clinical validation showed high concordance for viruses tested. Chapter 3, longitudinal sampling, showed that viral clearance was associated with clinical improvement after 3 days. However in some cases virus persisted after resolution of symptoms. This suggests that the detection of a viral RNA/DNA may not always reflect acute disease. Hence we performed a prospective case control study in asymptomatic and symptomatic young children in chapter 4. In 72 % of the cases and 28% of the controls at least one virus was identified. For rhinovirus, influenza a virus & coronavirus viral loads were significant higher in patients compared to controls. In chapter 5 we retrospectively studies analyzed fifty-four adenoids from non-clinically ill children. When testing for fourteen viruses, eighty percent of the adenoids, tested positive for one or more viruses. In chapter 6 immuncompromised adults were studied. The percentage of viruses found, was similar between patients with and without fever. In chapter 7 we addressed bacterial and viral detection. Bacterial pathogens, especially pneumococci, were found significantly more frequently in the presence of RSV. In chapter 8 the results of above studies are summarized and future perspectives are discussed addressing recent literature.