Novel Pseudomonas fluorescens septic sacroiliitis in a healthy soldier

Septic sacroiliitis is an uncommon infection of immunocompetent patients, typically caused by grampositive bacteria, with fewer gram-negative cases, and only 5% attributed to Pseudomonas species. We present a healthy soldier with the first reported case of Pseudomonas fluorescens septic sacroiliitis and discuss unique diagnostic and management issues. Because of its rare incidence and nonspecific presentation, septic sacroiliitis is often unrecognized, and its diagnosis is often delayed. Increased awareness of septic sacroiliitis as a potential disease process in the differential diagnosis of troops presenting with a combination of fever, low-back pain, and weight-bearing difficulty is important. As the young age and trauma exposure of the military population represent a prime demographic for this often unrecognized infection, delayed diagnosis can negatively impact a soldier's military readiness. P. fluorescens is itself a rare pathogen and often misidentified in the laboratory. Enhanced microbiological diagnostic techniques beyond routine culture and susceptibility testing should also be considered to account for less commonly seen pathogens. Although optimal antimicrobial treatment duration for infectious sacroiliitis is not well established, this case shows the early efficacy of oral antibiotics.