PURPOSE: Health care associated pneumonia (HCAP) has recently been described as a new and distinct entity. Certain risk factors included in the HCAP definition are associated with multi-drug resistant (MDR) pathogens. Therefore, our objective was to assess the recommended HCAP definition in order to identify MDR pathogens.
METHODS: A retrospective cohort study was conducted at two tertiary teaching hospitals. Data was abstracted on 787 eligible subjects that were admitted with a diagnosis of community acquired pneumonia (CAP) (by ICD-9 codes) between 1/1/1999 and 12/31/2001 and with radiologic confirmation. Subjects were excluded if they were “comfort measures only” or transferred from another acute care hospital. HCAP definition was modified according to IDSA/ATS recommendations (2005). A logistic regression analysis was performed with isolation or potential MDR pathogens (MRSA, Pseudomonas and Acinetobacter spp.) as the dependent measure, and the specific HCAP risk factors (prior antibiotic therapy, nursing home, hemodialysis, and immunosuppression) as the independent variables.
RESULTS: One hundred and eighty four patients had an identifiable microorganism of which 32 (17.4%) had potential MDR pathogens. When comparing pneumonia patients with potential MDR pathogens to those without MDR pathogens, they were more likely to be immunosuppressed (37.5% vs. 13.8%, p=0.002) and received prior to admission antibiotic therapy (28.1% vs. 7.2%, p=0.0002). However, there were no significant differences among groups related to admission from nursing homes (6.3% vs. 2.6%, p=0.3) or receiving hemodialysis (3.1% vs. 2.0%, p=0.7). After adjusting for severity of illness in the regression model, only prior antibiotic therapy (odds ratio [OR] =4.5, 95% confidence interval [CI] 1.6–12.7) and immunosuppression (OR=3.5, 95%CI 1.4–8.6) were associated with potential MDR pathogens. Pneumonia patients with HCAP were more likely to have potential MDR pathogens (OR=5.2, 95%CI 2.1–12.9) compared to CAP patients.
CONCLUSION: Prior antibiotic therapy and immunosuppression are the strongest predictors for potential MDR pathogens in patients with pneumonia.
CLINICAL IMPLICATIONS: Further studies should evaluate the impact of individual risk factors for multidrug resistant organisms for patients with pneumonia.
DISCLOSURE: Marcos Restrepo, No Financial Disclosure Information; No Product/Research Disclosure Information