The impact of bacteremia on the outcome of bone infections

We have used a medical database to analyze our activity since 2005. We observed a frequent association between bone and joint infection (BI) and bacteremia. Our aim was to characterize patients with BI and bacteremia, and focus on the outcome.

Our database includes the prospective recording of 28 characteristics of all hospitalized patients, including diagnosis, comorbid conditions, microbiological data, therapy, and outcome. We selected patients presenting with BI in this database, from July 2005 to December 2012. Fever before blood culture was retrospectively documented from the patient's chart. Chronic BI was defined as a disease lasting more than 1 month. An unfavorable outcome was defined by the need for intensive care or death.

Six hundred and thirty-two patients presented with BI and 125 with bacteremia (19.8%). We used a stepwise logistic regression analysis and determined that bacteremia was associated with vertebral osteomyelitis, OR, 3.97, P<0.001; alcohol abuse, OR, 2.51, P=0.010; fever, OR, 2.43, P<0.001; neurological and/or psychiatric diseases, OR, 2.41, P ≤ 0.001; and Staphylococcus aureus infection, OR, 2.32, P<0.001. The outcome was unfavorable in 23 cases (3.6%), associated with bacteremia, OR, 8.00, P<0.001, age> 60 years, OR, 4.78, P=0.018, and S. aureus infection, OR, 3.96, P=0.010. No single comorbid condition was significantly associated with an unfavorable outcome.

Bacteremia occurred in nearly 20% of the patients presenting with BI, and was associated with identifiable comorbid conditions; it was the main risk factor for an unfavorable outcome.