Giannella M, Trecarichi EM, De Rosa FG, et al. - Researchers performed a multicentre prospective matched case-control study of all adult carbapenem-resistant Klebsiella pneumoniae (CR-KP) rectal carriers hospitalized in five tertiary teaching hospitals in Italy over a 2-year period in order to determine the incidence and risk factors for CR-KP bloodstream infection (BSI) among rectal carriers. They compared 143 CR-KP BSIs with 572 controls without a documented infection during their hospitalization. As per the multivariate analysis, independent risk factors for CR-KP BSI development among CR-KP rectal carriers were admission to the Intensive Care Unit, abdominal invasive procedure, chemotherapy/radiation therapy, and number of additional colonization sites. Based on these four independent variables, they developed a CR-KP BSI risk score ranging from 0 to 28. A sensitivity, specificity, positive predictive value and negative predictive value of 93%, 42%, 29%, and 93%, respectively, were noted at a cut-off of ≥ 2 the model. in this large cohort of CR-KP rectal carriers, the strongest predictor of BSI development was colonization at multiple sites with CR-KP.