Viral and bacterial upper respiratory tract infection in hospital health care workers over time and association with symptoms

Raina MacIntyre, C.; Chughtai, Abrar Ahmad; Zhang, Yi; Seale, Holly; Yang, Peng; Chen, Joshua; Pan, Yang; Zhang, Daitao; Wang, Quanyi

Double rayon-tipped, plastic-shafted swabs were used to scratch both tonsilar areas and the posterior pharyngeal wall of participants. These samples were then transported immediately after collection to the Beijing CDPC laboratories, or stored at 4°C for up to 48 h if transport is delayed. Viral DNA/RNA was extracted from each respiratory specimen using the Viral Gene-spinTM Kit (iNtRON Biotechnology, Inc., Seoul, Korea) according to the manufacturer's instructions. Reverse transcription was performed using the RevertAidTM First Strand cDNA Synthesis Kit (Fermentas, ON, Canada) to synthesise cDNA. Multiplex PCR was carried out using the Seeplex® RV12 Detection Kit (Seegen, Inc., Seoul, Korea). A mixture of clones of the 12 viruses tested was used as a positive control template, and sterile deionised water was used as a negative control. Viral isolation by MDCK cell culture was undertaken for some of the influenza samples that are influenza NAT positive. NAT using a multiplex PCR was also done on the same DNA/RNA extract as used for the viral PCR (Seegen, Inc., Seoul, Korea). Specimen processing, DNA/RNA extraction, PCR amplification, and PCR product analyses were conducted in different rooms to avoid cross-contamination.