Increases in community-acquired infections caused by extended-spectrum-␤-lactamase (ESBL)-producingEnterobacteriaceae have important implications for hospital infection control and empirical antibiotic therapy protocols. We developed and validated a tool for identifying patients harboring these organisms at hospital admission. We retrospectively analyzed chart data for 849 adult inpatients

The increasing prevalence of colistin resistance (ColR) Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (Kp) is a matter of concern because of its unfavourable impact on mortality of KPC-Kp bloodstream infections (BSI) and the shortage of alternative therapeutic options. A matched case-control-control analysis was conducted. The primary study end point was to assess risk factors for ColR KPC-Kp BSI. The secondary end point was to describe mortality and clinical characteristics of these infections. To assess risk factors for ColR, 142 patients with ColR KPC-Kp BSI were compared to two controls groups: 284 controls without infections caused by KPC-Kp (control group A) and 284 controls with colistin-susceptible (ColS) KPC-Kp BSI (control group B). In the first multivariate analysis (cases vs. group A), previous colistin therapy, previous KPC-Kp colonization, ≥3 previous hospitalizations, Charlson score ≥3 and neutropenia were found to be associated with the development of ColR KPC-Kp BSI. In the second multivariate analysis (cases vs. group B), only previous colistin therapy, previous KPC-Kp colonization and Charlson score ≥3 were associated with ColR. Overall, ColR among KPC-Kp blood isolates increased more than threefold during the 4.5-year study period, and 30-day mortality of ColR KPC-Kp BSI was as high as 51%. Strict rules for the use of colistin are mandatory to staunch the dissemination of ColR in KPC-Kp-endemic hospitals.

The production of Klebsiella pneumoniae carbapenemases (KPCs) by Enterobacteriaceae has become a significant problem in recent years. To identify factors that could predict isolation of KPC-producing K. pneumoniae (KPCKP) in clinical samples from hospitalized patients, we conducted a retrospective, matched (1:2) case-control study in five large Italian hospitals. The case cohort consisted of adult inpatients whose hospital stay included at least one documented isolation of a KPCKP strain from a clinical specimen. For each case enrolled, we randomly selected two matched controls with no KPCKP-positive cultures of any type during their hospitalization. Matching involved hospital, ward, and month/year of admission, as well as time at risk for KPCKP isolation. A subgroup analysis was also carried out to identify risk factors specifically associated with true KPCKP infection. Since 2010, Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacteriaceae have caused numerous outbreaks of severe nosocomial infections in the northeastern United States, Israel, Greece, and Italy, and they are now considered endemic in these areas (1-9). Not only do KPC-producing organisms hydrolyze carbapenems, but also, they are often resistant to multiple other antibiotics (7, 9-11). Consequently, they are invariably associated with high treatment failure rates (3, 4, 7).Several relatively small studies have investigated risk factors for infection and/or colonization by carbapenem-resistant isolates of K. pneumoniae and other Gram-negative bacteria (5,8,(12)(13)(14)(15)(16). A recent review of these efforts found that the factors associated with colonization, infection, and mortality caused by these organisms vary considerably with the species and enzymatic profile of the isolate (5). Less attention has been focused specifically on KPCproducing strains of K. pneumoniae (KPCKP), and these studies have also been fairly small (17)(18)(19)(20). The reported rates of mortality related to KPCKP infections vary widely, from 22% to 72% (3,4,7,21). The risk obviously depends on factors like population age and underlying disease/comorbidity profiles, which were highly heterogeneous in the studies cited above. The criteria used to distinguish true KPCKP infections and simple colonization can also influence mortality rates. The term "infection" is frequently applied to cases characterized by isolation of KPCKP from clinical specimens (rather than rectal swabs collected for screening purposes). However, the presence of KPCKP in such samples-especially sputum and urine-can also reflect simple colonization. Therefore, this definition can favor overtreatment and distorts assessments of clinical outcomes.To clarify the inpatient risk factors associated with isolation of a KPCKP strain, we conducted a large, retrospective study in five Italian hospitals, where these organisms are an increasingly frequent cause of serious disease. A subgroup analysis was also carried out to identify risk factors specifically associated with true KPCKP infection. MAT...