[Pasteurella multocida infection of cavitated lung squamous carcinoma].

Pasteurella multocida has rarely been reported to cause lung disease in humans. Infection usually arises from bites or scratches from animal carriers of the pathogen. Cases of pneumonia, lung abscess, airway infection or infection of pre-existing bronchiectasis have been described, usually in individuals who are in direct contact with carrier animals and who have a chronic debilitating disease. It is unusual for P. multocida to be ingested and appear among oropharyngeal flora in humans. We report the first case published (Medline search 1966-2002) of a cavitated lung with squamous carcinoma that became infected by P. multocida in an elderly patient who denied contact with potential carrier animals. We believe that the P. multocida infection in humans is underdiagnosed because clinical suspicion is low and the bacterium is highly susceptible to common antibiotics.