aDivision of Infectious Diseases, Department of Medicine, University of Kansas Medical Center, Kansas City, Kansas

bDivision of Infectious Diseases, Department of Internal Medicine, University of California Davis Medical Center, Sacramento

cDepartment of Medical Microbiology and Immunology, University of California Davis, Davis, California, USA

Correspondence to George R. Thompson, MD, Department of Internal Medicine Division of Infectious Diseases, and Department of Medical Microbiology and Immunology, 4150 V Street, Suite G500, Sacramento, CA 95817, USA. Tel: +1 916 734 3556; e-mail: [email protected]