Group B streptococcal sacroilitis in an illicit drug abuser

Abstract

Introduction: Group B Streptococcus (GBS) is a usual neonatal pathogen, but the incidence in adult populations has risen recently. Pregnant women are at a higher risk of developing this infection. Invasive GBS is increasingly being recognized as one of the major pathogens in periprosthetic joint infections, but native joint infections are still rare. Serious invasive GBS disease can occur in adults with significant underlying medical conditions such as human immunodeficiency virus and active intravenous illicit drug use, as seen in our patient. Case presentation: We report the case of a 31‐year‐old man who presented with pain and decreased mobility of the right hip joint. He was human immunodeficiency virus positive and was actively abusing illicit drugs via the intravenous route. He was directly injecting into the groin, which contributed to setting up a focus of infection in the immediate vicinity, resulting in the development of bacteraemia and seeding the region by haematogenous spread. Magnetic resonance imaging revealed severe right‐sided sacroilitis and an iliopsoas abscess from direct contiguous spread. Culture of blood and pus from the iliopsoas abscess revealed GBS. The iliopsoas abscess was drained, and the patient was started on penicillin G therapy. The patient’s symptoms improved dramatically after just 2 weeks of therapy. Conclusion: We present this unusual clinical setting and site of infection, to highlight the increasing incidence of GBS native joint infections in susceptible non‐pregnant adults. The focus of GBS infection in this patient was unique and atypical, probably representing a contiguous spread of infection from the site of illicit drug injections. With an increasing incidence of GBS infections in non‐pregnant adults, it must be considered among the differential diagnoses of patients presenting with septic arthritis. Early recognition of GBS septic arthritis and prompt institution of treatment might prevent long‐term and often debilitating sequelae.