Microbiology of Musculoskeletal Infections in People Who Inject Drugs at a Rural Tertiary Care Center

Background Complex musculoskeletal (MSK) infections can occur in people who inject drugs (PWID) leading to significant morbidity. The purpose of this study was to update information on the anatomy and microbiology of MSK infections (MSKIs) in PWID, as well as 1-year outcomes at our hospital. Methods We identified adult patients admitted to Penn State Health Milton S. Hershey Medical Center from 2008 to 2018 with infection of the MSK system who self-reported injection drug use. The International Classification of Diseases, Ninth and Tenth Revisions, codes for MSKIs and diagnosis codes related to injection drug use were used to identify the cohort. Age, sex, ethnicity, race, date of admission for infection, location of infection, microbial etiology, method of treatment, comorbidities, and outcome at 1-year were recorded. Results Eighty-six distinct infections were found in 82 patients. Most patients were White, non-Hispanic, male, 50 years or younger. Hepatitis C and tobacco use disorder were common comorbidities. The axial skeleton was the most common site of infection. Staphylococcus aureus was the most frequent organism isolated followed by Pseudomonas aeruginosa. Spinal infections were primarily managed medically whereas septic joints were treated with surgery and antibiotics. Conclusions Infections of the MSK system are increasing in PWID. The axial skeleton is the site most often involved; S. aureus was the most frequently isolated organism with P. aeruginosa the next most common. Treatment may include surgical management, but all received antimicrobials. An unfortunate number had a relapse of infection, were lost to follow-up, or deceased at 1 year.