Gram stain morphology of
and patient's skin lesion. (A) Gram stain appearance of synovial fluid showing Gram negative bacilli and numerous polymorphs (1000× magnification). (B) Gram stain appearance of Streptobacillus moniliformis after passaging showing filamentous Gram negative bacilli with bulbous swellings arranging into chains and clumps. (C) Rat bite mark (arrow) over base of right thumb 10 days after being bitten.