"Sulphur granules" are seen in
a. Actinomycosis is an indolent, slowly progressive infection caused by anaerobic or microaerophilic bacteria, primarily of the genus Actinomyces, that colonize the mouth, colon, and vagina.
b. The responsible bacterial and/or host factors have not been identified.
c. Over time, sinus tracts to the skin, adjacent organs, or bone may develop.
d. In rare instances, distant hematogenous seeding may occur. As mentioned above, features of actinomycosis mimic malignancy, with which it is often confused.
e. The diagnosis is most commonly made by microscopic identification of sulfur granules (an in vivo matrix of bacteria, calcium phosphate, and host material) in pus or tissues. Occasionally, these granules are identified grossly from draining sinus tracts or pus
f. Although sulfur granules are a defining characteristic of actinomycosis, granules are also found in mycetoma and botryomycosis (a chronic suppurative bacterial infection of soft tissue or, in rare cases, visceral tissue that produces clumps of bacteria resembling granules).
g. These entities can easily be differentiated from actinomycosis with appropriate histopathologic and microbiologic studies. Microbiologic identification of actinomycetes is often precluded by prior antimicrobial therapy or failure to perform appropriate microbiologic cultures.
h. For optimal yield, the avoidance of even a single dose of antibiotics is mandatory.
i. Primary isolation usually requires 5–7 days but may take as long as 2–4 weeks.