(586) Prevalence of Patient-Specific Risk Factors for Pseudomonas aeruginosa Infection in ICU Patients

Introduction: Pseudomonas aeruginosa (PSA) is a gram-negative bacterium that is a common cause of nosocomial infections. Per guidelines, empiric anti-PSA therapy should be informed by several factors including likely source of infection, severity of illness, and patient-specific risk factors (RFs) for PSA infection. Failure to use anti-PSA agents for empirical treatment of PSA infection can cause adverse outcomes; however, studies have identified antimicrobial resistance of PSA due to the overuse of anti-PSA agents. The purpose of this study is to identify the prevalence of RFs for PSA infection to aid in clinical decision-making regarding the use of anti-PSA agents.

Methods: This retrospective study included adult patients admitted directly to an ICU or transferred to an ICU after a non-ICU admission in 2023 who had a positive PSA culture. A random sample of patients were evaluated for demographics, PSA infection RFs, infectious diagnoses, type and duration of anti-PSA agents, and mortality. Basic descriptive statistics were used to describe aggregate data.

Results: Ninety-four patients were included in this analysis, including 52 admitted and 42 transferred to an ICU. One hundred five cultures were positive for PSA with the most common sites being respiratory (39), urine (27), wound (26), and blood (11). The RFs for PSA with highest prevalence included: culture collected after 48 hours of hospitalization (52%), hospitalization within 90 days (52%), and IV antibiotics within 90 days (49%). At least one of these three RFs was present in 81% of patients. Additional RFs included: COPD (26%), CKD (23%), prior PSA culture within one year (14%), and active cancer (14%). At least one of these seven RFs was present in 90% of patients. Sepsis and septic shock were present in 68% and 33% of patients, respectively. Death occurred in 23% of patients.

Conclusions: In ICU patients with positive microbial cultures for PSA, there was a high prevalence of RFs associated with PSA. Clinicians should utilize a composite of multiple RFs in their clinical decision-making to increase their ability to identify patients at highest risk for PSA. Patients in this study also had high prevalence of sepsis, septic shock, and mortality, further emphasizing the need for recognition of those at high risk for PSA infection.