[1] Dept Pathol & Lab Med, Calgary, AB T2N 4N1, Canada
[2] Cumming Sch Med, Dept Med, Calgary, AB T2N 4N1, Canada
[3] Calgary Lab Serv, Microbiol Sect, Dept Clin, Calgary, AB T2N 4N1, Canada
[4] Dept Microbiol Immunol & Infect Dis, Calgary, AB T2N 4N1, Canada
[5] Univ Calgary, Dept Community Hlth Sci, Calgary, AB T2N 4N1, Canada