(A) Rat-bite scar (arrows) on the right thumb 19 days after the bite. (B) Swelling and redness in the right elbow. (C) T2-weighted, fat-saturated magnetic resonance imaging showing increasing effusion (red arrows) within the right elbow joint and high intensity of the surrounding soft tissues (yellow arrows) without osteomyelitis. (D) Gram staining from an anaerobic blood culture bottle (BD Bactec 22F) showing pleomorphic filamentous Gram-negative bacilli (magnification, ×1000).