Diagnostic yield and clinical impact of routine cell culture for respiratory viruses among children with a negative multiplex RT-PCR result

BACKGROUND: Polymerase chain reaction (PCR) is the reference standard for respiratory virus testing. However, cell culture may still have added value in identifying viruses not detected by PCR. OBJECTIVES: We aimed to estimate the yield and clinical impact of routine respiratory virus culture among children with a negative PCR result. STUDY DESIGN: A retrospective cohort study was performed from Jan. 2013 to Sept. 2015. Respiratory samples from hospitalized or immunocompromised patients <18 years old were routinely inoculated on traditional tube cell culture monolayers if they tested negative by a PCR assay for 12 respiratory viruses. We studied patients with a respiratory specimen negative by PCR and positive by culture. Duplicates and samples of sold services were excluded. Data on demographics, clinical history, laboratory findings, and patient management were collected from patients’ charts. Descriptive and multivariate statistics were performed. RESULTS: Overall, 4638 PCR-negative samples were inoculated in cell culture. Of those, 196 (4.2%) were cell culture positive, and 144 met study inclusion criteria. Most subjects (81.9%) were hospitalized. Mean age was 2.4 ± 3.4 years. The viruses most frequently isolated were cytomegalovirus (33.3%) and enteroviruses (19.4%). Cell culture results prompted a change in management in 5 patients (3.5%), all of whom had acyclovir initiated for localized HSV-1 infection. Four of these had skin or mucosal lesions that could be sampled to establish a diagnosis. CONCLUSION: In children, routine viral culture on respiratory specimens that were negative by PCR has low yield and minimal clinical impact.