RT Book, Section A1 Ryan, Kenneth J. SR Print(0) ID 1148674623 T1 Actinomyces and Nocardia T2 Sherris Medical Microbiology, 7e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9781259859809 LK accessbiomedicalscience.mhmedical.com/content.aspx?aid=1148674623 RD 2024/03/29 AB Actinomyces and Nocardia are gram-positive rods characterized by filamentous, tree-like branching growth, which has caused them to be confused with fungi in the past. They are opportunists that can sometimes produce indolent, slowly progressive diseases. A related genus, Streptomyces, is of medical importance as a producer of many antibiotics, but it rarely causes infections. Important differential features of these groups and of the mycobacteria to which they are related are shown in Table 28–1.