brucellaGram ⊝, aerobic coccobacillus.
Transmitted via ingestion of contaminated animal products (eg, unpasteurized milk).
Survives in macrophages in the reticuloendothelial system. Can form non- caseating granulomas. Typically presents with undulant fever, night sweats, and arthralgia.
Treatment: doxycycline + rifampin or streptomycin. microbiology HirotoShishido
histopathology of actinomyces(actinomycosis)
Diagnosis is made by identifying the bacteria with unique filamentous, branching patterns and the characteristic sulfur granules, which are formed by calcified mycelial fragments.
Sulfur granules grossly appear yellow; however, hematoxylin and eosin staining gives them an ☆amorphous (rosette -like) basophilic (purple/blue) appearance under light microscopy. microbiologyUWorld HirotoShishido
mecA geneencodes for penicillin binding protein (PBP) 2a
unlike other PBP, PBP 2a has ☆low affinity for beta-lactams and continues to cross link peptidoglycan in the presence of oxacillin, methicillin, ☆cephalosporins, and other beta lactam medications microbiologypharmacologyUWorld HirotoShishido