Psoas Abscess Precipitated by an Uncommon Pathogen: Pasteurella multocida.

A psoas abscess is a rare infection; it is an accumulation of purulent material within the psoas muscle. Common pathogens include Staphylococcus aureus, streptococci, Escherichia coli, and other enteric Gram-negative bacilli and anaerobes. These abscesses are thought to occur by either hematogenous spread, contiguous spread from adjacent organs, trauma, or local inoculation. Pasteurella multocida is a pathogen that usually infects a patient via a bite or scratch from dogs or cats and causes cellulitis at the site of the injury. Pasteurella multocida may also cause infection by the colonization of human respiratory and gastrointestinal (GI) tracts with spontaneous bacteremia seeding remote organs by the bacterial translocation process. Pasteurella multocida is highly susceptible to penicillins, cephalosporins, and other antibiotics. However, psoas abscesses usually require a drainage procedure as well as an extended course of antibiotics. We present a patient presenting with a psoas abscess due to P. multocida, an uncommon presentation of infection by this bacterium.