Background and Importance Carbapenem-resistant Enterobacteriaceae are a critical public health threat, and carbapenem use contributes to their spread. In 2012, an outbreak of carbapenemase KPC-producing Klebsiella pneumoniae (KPC-Kp) was reported in a tertiary-care hospital, causing a high mortality rate. To combat this problem, an antimicrobial stewardship programme (ASP) was implemented in 2014, which achieved a substantial reduction in carbapenem consumption and the incidence density (ID) of KPC-kp isolates two years after starting the programme .

Aim and Objectives To assess whether this reduction in KPC-kp isolates was indeed associated with a decrease in KPC-kp infections and associated mortality.

Material and Methods A quasi-experimental study was conducted in a tertiary-care hospital one year before (January 2013-January 2014) and two years after (February 2014-February 2016) the implementation of an ASP aimed at hospitalised adult patients treated with carbapenems. We assessed monthly ID of KPC-kp infections and 30-day crude death rate associated per 1000 occupied-bed days. The clinical category was classified according to the EUCAST breakpoints. Joinpoint regression analysis was used to model trends over time and identify the estimated location of any significant change in the slope of a trend line (Joinpoint Regression Program, version 4.9.1.0). A two-sided p-value of <0.05 was considered significant. Infection control indicator trends remained steady during study period.

Results A substantial reduction in KPC-kp infections was observed during post-intervention period, with a monthly change in slope of −2.9% (95% CI,−4.5 −1.3,p=0.01).The crude death rate of KPC-kp infections also showed a significant reduction after the intervention, with a monthly change in slope of −5.1% (95% CI,−8.5 −1.7,p=0.005).

Conclusion and Relevance Although most ASPs have reduced antibiotic consumption, recent systematic reviews have found no strong evidence of clinical and ecological impact of these interventions due to the small number of studies evaluating this relationship, as well as a large heterogeneity in study designs. Indeed, most ASPs have only shown the absence of deleterious effects of this reduction on mortality rates. This work provided new evidence, showing that the implementation of this ASP contributed to decreasing KPC-kp infections and the associated mortality, which was very high in our centre, probably due to the lower incidence of these infections associated with reduced use of carbapenems.

Conflict of Interest No conflict of interest