Norcardia
aerobic, gram-positive, and partially acid-fast filamentous rod
Catalase positive, urease positive
appears beaded or branching; endemic in soil
disease follows inhalation of aerosolized saprophytes OR traumatic inoculation into skin
most common in immunocompromised or elderly patients and affects the brain, soft tissue/skin, and lungs
skin infection usually follow traumatic inoculation (eg, puncture wound while gardening) and presents with fever and purulent crusting lesions or ulcers
Tx
Sulfonamides; Bactrim (TMP-SMX)
Actinomyces israelii
branching gram-positive, filamentous rod;
Non-acid fast
It is not found in the environment, and humans are the only reservoir for the species, causing cervicofacial disease.
Host has a normal immune system; a part of normal mouth flora
The disease occurs by direct invasion of the organism
check history of facial or dental trauma including gingivitis, dental caries, and extraction, which inoculated these organisms into the cervicofacial area
It usually presents as a chronic, slow growing, non-tender mass, which slowly evolves into multiple abscesses, fistulae, and draining sinus tracts with thick yellow or serous discharge.