Department of Infectious Diseases, Laboratory of Clinical Microbiology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico. Merck & Co., Inc, Kenilworth, NJ, USA. Institute for Clinical Research and Health Policy Studies, Center for Clinical Evidence Synthesis, Tufts Medical Center, 800 Washington St, Boston, MA, 02111, USA. Tufts University School of Medicine, Boston, MA, USA. Institute for Clinical Research and Health Policy Studies, Center for Clinical Evidence Synthesis, Tufts Medical Center, 800 Washington St, Boston, MA, 02111, USA. eavendano@tuftsmedicalcenter.org.