Background: Carbapenem-resistant Enterobacterales (CRE) are common causes of healthcare-associated infections and are often multidrug resistant with limited therapeutic options. Additionally, CRE can spread within and between healthcare facilities, amplifying potential harms.
Objective: To better understand the burden, risk factors, and source of acquisition of carbapenemase genes in clinical Escherichia coli and Klebsiella spp isolates from patients in Washington to guide prevention efforts.
Design: Multicenter prospective surveillance study.
Methods: Escherichia coli and Klebsiella spp isolates meeting the Washington state CRE surveillance case definition were solicited from clinical laboratories and tested at Washington Public Health Laboratories using polymerase chain reaction (PCR) for the 5 most common carbapenemase genes: blaKPC, blaNDM, blaIMP, blaVIM, and blaOXA-48. Case patients positive by PCR were investigated by the public health department.
Results: From October 2012 through December 2017, 363 carbapenem-resistant E. coli and Klebsiella spp isolates were tested. Overall, 45 of 115 carbapenem-resistant K. pneumoniae (39%), 1 of 8 K. oxytoca (12.5%), and 28 of 239 carbapenem-resistant E. coli (11.7%) were carbapenemase positive. Of 74 carbapenemase-positive isolates, blaKPC was most common (47%), followed by blaNDM (30%), blaOXA-48 (22%), and blaIMP (1%). Although all cases had healthcare exposure, blaKPC acquisition was associated with US health care, whereas non-blaKPC acquisition was associated with international health care or travel.
Conclusions: We report that blaKPC, the most prevalent carbapenemase in the United States, accounts for nearly half of carbapenemase cases in Washington state and that most KPC-cases are likely acquired through in-state health care.