[1] Parramatta Sexual Hlth Clin, Parramatta, NSW 2150, Australia
[2] Univ Sydney, Westmead Hosp, Ctr Infect Dis & Microbiol, Lab Serv,Inst Clin Pathol & Med Res, Westmead, NSW 2145, Australia
[3] Sydney Hosp, Sydney Sexual Hlth Ctr, Sydney, NSW 2000, Australia
[4] Sexually Transmitted Infect Res Ctr, Westmead, NSW 2145, Australia