A patient appeared in the emergency room with a submandibular mass. A smear was made of the drainage and a bewildering variety of bacteria were seen, including branched, Gram-positive rods. The most clinically appropriate action is
The patient has actinomycosis. These laboratory data are not uncommon. There is no reason to work up all the contaminating bacteria. A fluorescent microscopy test for A. israelii is available. If positive, the FA provides a rapid diagnosis. In any event, it may be impossible to recover A. israelii from such a specimen. High-dose penicillin has been used to treat actinomycosis.
Do no further clinical workup
Suggest to the laboratory that low colony counts may reflect infection
Determine if fluorescent microscopy is available for the diagnosis of actinomycosis
Consider vancomycin as an alternative drug
Bacteria