sábado, 9 de noviembre de 2013

CTX-M β-Lactamase–producing Klebsiella pneumoniae in Suburban New York City, New York, USA - Vol. 19 No. 11 - November 2013 - Emerging Infectious Disease journal - CDC

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CTX-M β-Lactamase–producing Klebsiella pneumoniae in Suburban New York City, New York, USA - Vol. 19 No. 11 - November 2013 - Emerging Infectious Disease journal - CDC

Attributed to the Sappho Painter Odysseus Escaping from the Cave of Polyphemos (detail) (c. 2500 years ago) Attic black-figured column-krater, ceramic. Courtesy of the Michael C. Carlos Museum of Emory University, Atlanta, Georgia, USA. Photo by Bruce M. White, 2004

Volume 19, Number 11—November 2013

Research

CTX-M β-Lactamase–producing Klebsiella pneumoniae in Suburban New York City, New York, USA

Guiqing WangComments to Author , Tiangui Huang, Pavan Kumar Makam Surendraiah, Kemeng Wang, Rashida Komal, Jian Zhuge, Chian-Ru Chern, Alexander A. Kryszuk, Cassidy King, and Gary P. Wormser
Author affiliations: New York Medical College, Valhalla, New York, USA
Suggested citation for this article

Abstract

CTX-M extended-spectrum β-lactamase (ESBL)–producing Klebsiella pneumoniae isolates are infrequently reported in the United States. In this study, we analyzed nonduplicate ESBL-producing K. pneumoniae and Escherichia coli clinical isolates collected during 2005–2012 at a tertiary care medical center in suburban New York City, USA, for the presence of blaCTX-M, blaSHV, blaTEM, and blaKPC genes. Despite a high prevalence of blaCTX-M genes in ESBL-producing E. coli since 2005, blaCTX-M genes were not detected in K. pneumoniae until 2009. The prevalence of CTX-M–producing K. pneumoniae increased significantly over time from 1.7% during 2005–2009 to 26.4% during 2010–2012 (p< 0.0001). CTX-M-15 was the dominant CTX-M genotype. Pulsed-field gel electrophoresis and multilocus sequence typing revealed high genetic heterogeneities in CTX-M–producing K. pneumoniae isolates. This study demonstrates the recent emergence and polyclonal spread of multidrug resistant CTX-M–producing K. pneumoniae isolates among patients in a hospital setting in the United States.
CTX-M enzymes are a group of class A extended-spectrum β-lactamases (ESBLs) that are rapidly spreading among Enterobacteriaceae worldwide (1). Since the initial isolation of CTX-M-1 from a European patient in the late 1980s (2), > 130 CTX-M allelic variants have been described (http://www.lahey.org/Studies/other.asp#table1External Web Site Icon). These CTX-M variants have been divided into 5 major phylogenetic groups, CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9, or CTX-M-25 on the basis of their amino acid sequences (1,2).
During the past decade, CTX-M enzymes have become the most prevalent ESBL enzymes in clinical Enterobacteriaceae isolates, especially in ESBL-producing Escherichia coli in Europe, Asia, and South America (1,3). By contrast, SHV- and TEM-type ESBL enzymes are primarily found in ESBL-producing K. pneumoniae and E. coli clinical isolates in North America (3). In the United States, CTX-M–like ESBL-producing Enterobacteriaceae was first reported in 2003, when CTX-M enzymes were detected in 9 E. coli clinical isolates from 5 US states (4). The spread of CTX-M type ESBL in Enterobacteriaceae, however, was not appreciated until 2007 when a Texas study showed a high prevalence of CTX-M ESBL in E. coli clinical isolates recovered during 2000–2005 (5). Since then, CTX-M–producing E. coli isolates have been documented in dispersed US geographic regions (3,6,7). CTX-M enzymes are now the predominant ESBL type in E. coli clinical isolates in Texas (5), Pennsylvania (6), Illinois (8), and New York (9,10).

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