1. Infectious Diseases Service, Hospital Universitario “Dr. José E. González” and Medical School, Universidad Autónoma de Nuevo León, Madero y Gonzalitos S/N, 64460 Monterrey, NL, Mexico
2. Department of Internal Medicine, Hospital Universitario “Dr. José E. González” and Medical School, Universidad Autónoma de Nuevo León, Madero y Gonzalitos S/N, 64460 Monterrey, NL, Mexico