[1] Newcastle Univ, Inst Cellular Med, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England
[2] Newcastle Upon Tyne Hosp NHS Fdn Trust, Paediat Resp Unit, Newcastle Upon Tyne, Tyne & Wear, England
[3] Newcastle Upon Tyne Hosp NHS Fdn Trust, Freeman Hosp, Dept Microbiol, Newcastle Upon Tyne, Tyne & Wear, England
[4] Newcastle Univ, Inst Cell & Mol Biosci, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England