Background Bacteria-producing extended spectrum β-lactamase (ESBL) enzymes are resistant to commonly used antimicrobials. In 2008, routine monitoring revealed a clonal hospital outbreak of ESBL-producing Klebsiella pneumoniae (ESBL-KP).

Methods At a 510-bed Danish university hospital, a multidisciplinary change project inspired by Kotter's Eight Steps of Change was designed. In addition to revision of antimicrobial guidelines and restriction of selected antimicrobials, the complex, managed, multi-faceted intervention comprised training and education, enhanced isolation precautions, and a series of actions to improve the infection control measures and standardise procedures across the hospital. A prospective interrupted time series design was used to analyse data collected at hospital level from January 2008 through December 2011.

Results Though overall antimicrobial consumption remained unaffected, the intervention led to intended, immediate and sustained reduction in the use of cefuroxime, and an increase in the use of ertapenem, piperacillin/tazobactam and β-lactamase sensitive penicillin. Moreover, a postintervention reduction in the rate of ESBL-KP in diagnostic samples and in the incidence of ESBL-KP infections was observed. The intervention may also have reduced the need for isolation precautions and may have shortened each isolation period.

Conclusions The results indicate that an immediate and sustained change in the antimicrobial consumption and a decreasing rate of ESBL-KP are achievable through the application of a managed, multi-faceted intervention that does not require ongoing antibiotic stewardship.