Trends in Klebsiella pneumoniae carbapenemase-positive K. pneumoniae in US hospitals: report from the 2007-2009 SENTRY Antimicrobial Surveillance Program

Abstract

We report the prevalence of carbapenemase-positive Klebsiella pneumoniae among clinical isolates collected from US medical centers (n = 42) from 2007-2009 through the SENTRY Antimicrobial Surveillance Program. Isolates with imipenem or meropenem MIC ≥ 2 μg/mL were screened by PCR for various carbapenemase genes. Of 2049 K. pneumoniae isolates, 126 (6.1%) were non-susceptible to imipenem or meropenem. blaKPC was identified in 113 isolates (5.5%). No other carbapenemase genes were identified. For US regions combined, prevalence of K. pneumoniae carbapenemase (KPC)-positive isolates were 5.9% in 2007, 4.9% in 2008, and 5.7% in 2009. Rates were highest in the Mid-Atlantic region (28.6% overall), with fluctuation over time (29%, 23%, and 33% from 2007-2009), followed by the East North Central region (2.4% overall), with a slightly increasing trend (nil, 3.1%, 3.8% from 2007-2009). All KPC-positive organisms were carbapenem non-susceptible according to updated CLSI breakpoints, although all but one was similarly classified according to previous breakpoints.