RT Book, Section
A1 Bravo, Francisco G.
A1 Arenas, Roberto
A1 Sigall, Daniel Asz
A2 Goldsmith, Lowell A.
A2 Katz, Stephen I.
A2 Gilchrest, Barbara A.
A2 Paller, Amy S.
A2 Leffell, David J.
A2 Wolff, Klaus
SR Print(0)
ID 56084611
T1 Chapter 185. Actinomycosis, Nocardiosis, and Actinomycetoma
T2 Fitzpatrick's Dermatology in General Medicine, 8e
YR 2012
FD 2012
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-166904-7
LK accessmedicine.mhmedical.com/content.aspx?aid=56084611
RD 2024/04/19
AB Actinomyces  and  Nocardia  are  a  group  of  filamentous  bacteria  belonging  to  the  same  class,  Actinobacteria,  and  same  order,  Actinomycetales.  They  cause  human  disease  with  prominent  skin  involvement.  Microorganisms  under  this  category  were  wrongly  classified  as  fungi  for  a  long  time,  because  of  their  tendency  to  produce  branching  filaments,  mimicking  radiating  hyphae  (from  the  Greek  actino,  meaning  sun).  Their  taxonomy  is  still  evolving,  resulting  in  continuous  reclassification  of  different  species  in  old  and  new  families.  Anaerobic  endogenous  Actinomyces,  part  of  our  normal  respiratory,  intestinal,  and  genitourinary  flora,  will  cause  localized  suppurative  disease  with  fistula  formation  that  is  analogous  to  the  lumpy  jaw  of  cattle.  Aerobic  environmental  Nocardia  sp.  cause  diseases  ranging  from  cellulitis  to  paronychia  to  abscesses,  with  the  most  striking  presentation  being  a  lymphocutaneous,  sporotrichoid  syndrome.  In  addition,  other  aerobic  environmental  species  of  Nocardia  and  Actinomyces  will  cause  one  of  the  two  known  forms  of  mycetoma,  the  actinomycetoma.