[1] Univ Leicester, Dept Resp Sci, Leicester, England
[2] Univ Hosp Leicester NHS Trust, Dept Resp Med, Leicester, England
[3] Univ Hosp Leicester NHS Trust, Dept Clin Microbiol, Leicester, England
[4] Univ Leicester, Sch Comp & Math Sci, Leicester, England
[5] Univ Leicester, Dev Ctr Populat Hlth, Leicester, England