NSF, Branching, Aerobic Actinomycetes

• Nocardia

  • resembles fungi but are true bacteria
  • partially acid fast
• Nocardia

  Virulence Factors: None have been identified

  Clinical infections:

  1. Pulmonary infections - Confluent bronchopneumonia
  2. Cutaneous Infection - Nocardia brasiliensis is the most frequent cause of this form of nocardiosis and actinomycotic mycetomas.

  • Pus: pigmented and has sulfur granules
  • Granules: yellow or orange
• Nocardia

  Laboratory diagnosis: Cultural characteristics

  • Modified Thayer-Martin agar
  • Buffered charcoal-yeast extract agar
  • A chalky, matte, velvety, or powdery appearance and may be white, yellow, pink, orange, peach, tan, or gray pigmented
  • Dry, crumbly appearance similar to breadcrumbs
• Actinomadura madurae and A. pelletieri

  1. causes mycetomas that is identical to those caused by Nocardia spp.
  2. madurae is cellobiose and xylose positive, whereas Nocardia spp. do not produce acid from these two carbohydrates
• Streptomyces

  • Primarily saprophytes found as soil inhabitants and resemble other aerobic actinomycetes with regard to morphology and the diseases they cause
• Gordonia

  • Grow with mycelial forms that fragment into rod- shaped or coccoid elements – hence the term, nocardioform
  • They differ from rapidly growing mycobacteria by their weak acid fastness and the absence of arylsulfatase
• Rhodococcus equi

  • Found in soil and causes respiratory tract infections in animals
  • Human infection is rare
  • Demonstrate filaments, some with branching
  • Partially acid fast or acid fast
• Tropheryma whipplei

  • Agent of Whipple disease - rare bacterial infection; disease that often affects joints and the digestive system
  • Facultative intracellular pathogen - first identified during the 1991 with the use of PCR from duodenal biopsy specimen
  • Detected in human feces, saliva, and gastric secretions and is apparently ubiquitous in the environment