1. Department of Infectious Disease, Hospital Manuel Gea González, Mexico City, Mexico
2. Department of Infectious diseases. Hospital de Especialidades ‘Dr. Antonio Fraga Mouret’, Centro Médico Nacional La Raza del Instituto Mexicano del Seguro Social, Mexico City, Mexico
3. Department of Infectious Diseases, Hospital General de Zona No. 27, Instituto Mexicano del Seguro Social, Mexico City, Mexico