Risk factors for recurrent carbapenem resistant Klebsiella pneumoniae bloodstream infection: a prospective cohort study.

To assess risk factors for recurrent carbapenem-resistant Klebsiella pneumoniae bloodstream-infection (CR-KP BSI), we performed a prospective observational cohort study of all consecutive adult patients cured of a CR-KP BSI at our hospital over a six-year period (June 2010 to June 2016). Maximum follow-up per patient was 180 days from the index blood cultures (BCs). Recurrent CR-KP BSI was defined as new evidence of positive BCs in patients with documented clinical response after completing a course of anti-CR-KP therapy. Univariate and multivariate cause-specific Cox proportional hazards analysis were performed. During the study period 249 patients were diagnosed with a CR-KP BSI, 193 were deemed as cured within 14 days after index BCs and were analysed. Recurrence occurred in 32/193 patients (16.6%) within a median of 35 (IQR 25-45) days after index BCs. All but one of the recurrences occurred within 60 days after the index BCs. Comparison of recurrent and non-recurrent cases showed significant differences for colistin use (84.4% vs. 62.2%, p = 0.01), meropenem-colistin-tigecycline regimen (43.8% vs. 24.8%, p = 0.03) and length of therapy for the index BSI episode (median 18 vs. 14 days, p = 0.004). All-cause 180-day mortality (34.4% vs. 16.1%, p = 0.02) was higher in recurrent cases. In the multivariate analysis, the only independent variable was source control as a protective factor for recurrence. Recurrence is frequent among patients cured of a CR-KP BSI and is associated with higher long-term mortality. When feasible, source control is mandatory to avoid recurrence. The role of antibiotic treatment should be further investigated in large multicentre studies.