[1] Newcastle Univ, Sch Med, Inst Cellular Med, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England
[2] Newcastle Univ, Sch Med, Inst Cell & Mol Biosci, Newcastle Upon Tyne NE2 4HH, Tyne & Wear, England
[3] Newcastle Upon Tyne Hosp NHS Fdn Trust, Freeman Hosp, Dept Microbiol, Newcastle Upon Tyne NE7 7DN, Tyne & Wear, England
[4] Royal Victoria Infirm, Adult Cyst Fibrosis Ctr, Newcastle Upon Tyne NE1 4LP, Tyne & Wear, England
[5] Royal Victoria Infirm, Northern Oesophago Gastr Unit, Newcastle Upon Tyne NE1 4LP, Tyne & Wear, England