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Abstract

Introduction: Based upon ATS/IDSA guideline recommendations for the management of adults with healthcare-associated pneumonia, patients with early-onset infection (within 4 days of admission) without risk factors for multidrug-resistant (MDR) pathogens should receive empiric monotherapy. However, more recent data suggests that this early- and late-onset classification should be abandoned as similar pathogens and mortality have been identified in the two subgroups of patients. Hypothesis: We hypothesize that there is no difference in the incidence of MDR pathogens between episodes of early-onset and late-onset pneumonia within our institution. Methods: We conducted a retrospective chart review of respiratory cultures (endotracheal aspirates and bronchoalveolar lavages) obtained at our institution between June 2008 and December 2011. Results: Five hundred eighty four cultures were reviewed to include 150 patients. Thirty-nine of 65 (60%) patients with early-onset pneumonia had infection with MDR organisms versus 63 of 85 (74%) patients with late-onset pneumonia (p=0.07). In patients with early-onset pneumonia with and without risk factors, MDR organisms accounted for 24 of 33 (73%) and 15 of 32 (47%) infections, respectively (p=0.04). Compared to the 47% incidence of MDR pathogens in patients without risk factors, MDR organisms were identified in 74% (87 of 118) of all patients with expected risk of MDR pathogens (late onset/other risk factors) (p=0.005). No difference was observed in mechanical ventilator-free days, intensive care unit length of stay, or mortality between the latter two groups described. Conclusions: We observed a similar incidence of infection with MDR pathogens in patients with early- and late-onset pneumonia; however, more MDR pathogens were observed in patients with risk factors for MDR pathogens regardless of timing of onset. While this study confirms the high incidence of pneumonia associated with MDR organisms in patients with risk factors, half of patients with early-onset pneumonia without identified risk factors experienced infection with MDR organisms. Consideration should be given to broad-spectrum empiric antibiotic regimens in patients with early-onset pneumonia in our hospital.