BSCI 424 — PATHOGENIC MICROBIOLOGY — Fall 2000

Actinomycetes Summary

  Cell Walls with Mycolic Acids (often referred to as the "CMN group"):

Family Corynebacteriaceae

Corynebacterium

Family Mycobacteriaceae

Mycobacterium

Family Nocardiaceae:

Nocardia
Rhodococcus

  Cell Walls without Mycolic Acids:

Actinomadura

Rothia spp.

Streptomyces

Clinically Significant Anaerobic Actinomycetes:

  Cell Walls without Mycolic Acids:

Actinomyces

Bifidobacterium

Eubacterium

Lactobacillus

Propionibacterium

Rothia spp.

  Gram-positive bacteria that produce fungi-like structures include that include delicate filaments (often called hyphae or mycelia as per the similar structures produced by true fungi) and aerial filaments which may branch, fragment into spores, or become pigmented

  Actinomyces are morphologically similar to Nocardia except that they Actinomyces are not acid-fast, lacking mycolic acids in the cell wall

  Cause three major types of infections:

1. actinomycosis;
2. nocardiosis;
3. actinomycetoma (actinomycotic mycetoma)

  Actinomycosis is a chronic infection, both suppurative and granulomatous; characterized by pus-filled lesions (abscesses) and interconnecting sinus tracts that contain granules of microcolonies imbedded in tissue elements; ultimately with bone involvement

  Nocardiosis can be an acute infection but more often presents as a chronic suppurative infection, primarily a bronchopulmonary disease with predilection for secondary spread through blood to central nervous system or skin; occasionally a primary cutaneous or ocular infection or mycetoma

  Actinomycetoma (actinomycotic mycetoma) is a chronic localized subcutaneous infection characterized by swelling, pus, formation of sinus tracts, with limited granulomas draining into sinuses (not referring to nasal sinuses)

BSCI 424 — Pathogenic Microbiology — BSCI 424 HomePage