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Molecular and phenotypic characterization of Escherichia coli and Klebsiella pneumoniae producing extended‐spectrum β‐lactamases with focus on CTX‐M in a low‐endemic area in Sweden
Author(s) -
ÖNNBERG ANNA,
MÖLLING PAULA,
ZIMMERMANN JOHANNA,
SÖDERQUIST BO
Publication year - 2011
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1111/j.1600-0463.2011.02730.x
Subject(s) - klebsiella pneumoniae , escherichia coli , microbiology and biotechnology , biology , enterobacteriaceae , plasmid , molecular epidemiology , genotype , klebsiella , dominance (genetics) , gene , genetics
Önnberg A, Mölling P, Zimmermann J, Söderquist B. Molecular and phenotypic characterization of Escherichia coli and Klebsiella pneumoniae producing extended‐spectrum β‐lactamases with focus on CTX‐M in a low‐endemic area in Sweden. APMIS 2011; 119: 287–95. During the last decade increasing prevalence of extended‐spectrum β‐lactamase (ESBL)‐producing Enterobacteriaceae has been detected worldwide, mainly due to dissemination of Escherichia coli and Klebsiella pneumoniae producing CTX‐M‐type ESBLs. CTX‐M‐15 is the most widespread CTX‐M type, and the predominant type in various countries. Dissemination of ESBL‐producing organisms is caused not only by horizontal transfer of plasmids, but also by clonal spread of ESBL‐producing strains. In this study, the molecular epidemiology of class A ESBL (ESBL A )‐producing E. coli and K. pneumoniae isolated in Örebro County, Sweden, was investigated. Out of 200 ESBL A ‐producing E. coli and K. pneumoniae isolates, collected over a 10‐year period, 87% were producing CTX‐M, belonging to subgroup CTX‐M‐1 (64%), CTX‐M‐9 (34%), or CTX‐M‐2 (2%). The remaining isolates were producing variants of SHV and TEM. Sequencing of the bla CTX‐M genes revealed 10 different CTX‐M types, with a dominance of CTX‐M‐15 ( E. coli 54%, K. pneumoniae 50%) followed by CTX‐M‐14 ( E. coli 28%, K. pneumoniae 27%). Phenotypic characterization of the CTX‐M‐producing isolates was performed using the PhenePlate system. Although a few minor clusters of CTX‐M‐15 and CTX‐M‐14 producers were identified, the majority of the isolates did not appear to be clonally related.