Pseudomonas aeruginosa bacteremia: resistance to antibiotics, risk factors, and patient mortality

The aim of our study was to determine the prevalence of Pseudomonas aeruginosa bacteremia, risk factors, and outcome of patients treated at the Hospital of Kaunas University of Medicine.
Material and methods. All hospitalized patients with blood culture positive for Pseudomonas aeruginosa during the 5-year period were included. A retrospective data analysis was performed to evaluate patients’ risk factors and mortality caused by P. aeruginosa bacteremia.
Results. A total of 47 (58.8%) bacteremia episodes occurred in an intensive care unit (ICU). A primary source of bacteremia was identified in 50 (62.5%) episodes. Overall mortality rate was 58.8%. Univariate risk factors analysis showed the factors, which significantly increased the risk of death: mechanical ventilation (13.67 times, P<0.001), patient hospitalization in the ICU (8.51 times, P<0.001), acute respiratory failure (8.44 times, P<0.001), infection site in the respiratory tract (4.93 times, P=0.003), and central vein catheter (4.44 times, P=0.002). Timely and appropriate treatment and surgery were significant protective factors for 30-day mortality (11.1 and 5.26 times, respectively; P=0.001). Meropenem-resistant Pseudomonas aeruginosa strains caused bacteremia more frequently in patients older than 65 years than meropenem-sensitive strains (57.9%, n=11). All 19 patients with meropenem-resistant Pseudomonas aeruginosa bacteremia received inappropriate empirical antibiotic therapy.
Conclusions. Treatment at the intensive care unit, mechanical ventilation, acute respiratory failure, source of infection in respiratory tract, and central vein catheter are the major risk factors associated with an increased mortality rate in patients with Pseudomonas aeruginosa bacteremia. The patients older than 65 years are at increased risk for bacteremia caused by carbapenemresistant Pseudomonas aeruginosa strains. Carbapenems are not antibiotics of the choice of treatment for Pseudomonas aeruginosa bacteremia at the Hospital of Kaunas University of Medicine.