Positive Ziehl-Neelsen sputum stain, with magenta-colored acid-fast bacilli on a blue background. (Courtesy of the Centers for Disease Control and Prevention.) Source: Infectious Disease, Principles and Practice of Hospital Medicine, 2e Citation: McKean SC, Ross JJ, Dressler DD, Scheurer DB. Principles and Practice of Hospital Medicine, 2e; 2017 Available at: http://accessmedicine.mhmedical.com/DownloadImage.aspx?image=/data/books/1872/mckeanhm2_ch200_f004.png&sec=146986005&BookID=1872&ChapterSecID=146948420&imagename= Accessed: October 27, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved