Herpes simplex virus-1 qPCR in the diagnosis of lower respiratory tract infections in organ transplant recipients and critically ill patients

Abstract

Objectives: To determine a quantitative herpes simplex virus (HSV) DNA threshold in lower respiratory tract specimens that correlates with positive viral culture and clinical outcomes. Methods: Bronchoalveolar lavage and bronchial wash samples from 53 HSV culture-positive and 61 culture-negative matched controls were tested using HSV-1 and HSV-2 quantitative polymerase chain reaction (qPCR). Results: Median viral culture turnaround time was 21.8 days and 9.9 days for culture-negative and culture-positive specimens, respectively. Using an HSV-1 viral load threshold of 1.62 × 10 3 copies/mL, there was 93% agreement with viral culture. An HSV-1 viral load ≥1.3 × 10 4 copies/mL was associated with worse clinical outcome compared to a viral load <1.3 × 10 4 copies/ mL (hazard ratio [HR] = 4.27, P = .017), and there was a trend of worse outcome compared to patients with undetectable HSV-1 DNA (HR = 1.60, P = .056). Conclusions: qPCR has clinical utility for rapid accurate identification of HSV-1 in lower respiratory tract specimens.