A truck driver was involved in a serious accident and received second and third degree burns over his body. He was placed in the burn unit and, on his twelfth day of his admission, developed a wound infection with a bluish-green exudate. Treatment with chloramphenicol and tetracycline was unsuccessful. A gram-negative, motile organism was isolated that was oxidase-positive, did not ferment lactose, sucrose, or glucose, but grew on MacConkey's agar and produced a fruity aroma on that medium. Which of the following organisms was most likely isolated?