[1] Univ Madras, Dept Microbiol, Dr AL Mudaliar Post Grad Inst Basic Med Sci, Madras 600113, Tamil Nadu, India
[2] Univ Texas Hlth Sci Ctr San Antonio, Dept Microbiol & Immunol, San Antonio, TX 78229 USA
[3] Govt Hosp Thorac Med, Chennai, Tamil Nadu, India