Successful containment of carbapenem-resistant Enterobacteriaceae by strict contact precautions without active surveillance.

Background: Carbapenem-resistant Enterobacteriaceae (CRE) are a growing problem worldwide. Guidelines focus on carbapenemase-producing organisms, and little is known about whether strict adherence to infection control measures is effective for CRE without carbapenemase. During 2009, CRE increased markedly in a tertiary hospital, and enhanced infection control measures without active surveillance were adopted.

Methods: Beginning in April 2010, enhanced antimicrobial stewardship, strict contact precautions, and cohort isolation were adopted. After September 2010, hand hygiene performance was prospectively monitored by active surveillance, and results were monthly fed back to medical personnel. Available carbapenem-resistant Escherichia coli (ECO) and carbapenem-resistant Klebsiella pneumoniae (KPN) isolated during 2008-2010 were characterized. Imipenem and meropenem minimal inhibitory concentrations were confirmed by E-test (AB biodisk, Solna, Sweden). Phenotypic screening assays and polymerase chain reaction (PCR) amplification of known β-lactamase and carbapenemase genes were performed.

Results: From 3,511 ECO and 2,279 KPN, 44 (0.76%) were CRE (3 ECO, 41 KPN). CRE incidence rates rose from 1.61 in 2008 to 5.49 in 2009; they rose further to 9.81 per 100,000 patient days in early 2010. After adoption of strict infection control measures, CRE frequency fell back in 2011 and remained at baseline afterward. Phenotypic screening and PCR showed AmpC β-lactamase and extended spectrum β-lactamases with or without loss of porins; carbapenemases were not detected.

Conclusion: Enhanced infection control measures, even without active surveillance, seem effective to prevent further spread of CRE in a low-prevalence setting with mainly carbapenemase-nonproducing CRE.