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

Abstract

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.

Transcriptional Alterations of Virulence-Associated Genes in Extended Spectrum Beta-Lactamase (ESBL)-Producing Uropathogenic Escherichia coli during Morphologic Transitions Induced by Ineffective Antibiotics

“…The ESBL-producing UPEC was originally isolated from a patient at Örebro University hospital, Sweden. The isolate, designated ESBL019 (previously named ESBL7, Demirel et al, 2015), has previously been characterized and determined to be multidrug resistant (CTX-M-15) and resistant to ceftibuten (MIC 7,680 ng/ml) and belongs to the ST131 clone (Onnberg et al, 2011). ESBL019 was grown in Luria broth (Difco Laboratories, Detroit, MI, USA) overnight on shake at 200 rpm 37°C.…”

Comparison of host response mechanisms evoked by extended spectrum beta lactamase (ESBL)- and non-ESBL-producing uropathogenic E. coli

“…The identity of the patients was anonymized and after that further analyses of the strains were performed. Antimicrobial susceptibility testing was performed as recommended by the Swedish Reference Group for Antibiotics (http://www.srga.org) and the isolates were genetically characterized for CTX-M, TEM and SHV type by real time PCR and nucleotide sequencing and stored as previously described [16]. MG1655, a well-characterized and non-pathogenic E. coli K-12 strain and CFT073, a UPEC strain isolated from a patient with pyelonephritis, were used as control strains.…”

Ceftibuten-induced filamentation of extended spectrum beta lactamase (ESBL)-producing uropathogenic Escherichia coli alters host cell responses during an in vitro infection

“…Renal epithelial cells were stimulated with three different ESBL isolates (two known cytokine-inducers (ESBL7 and 8) and one non- Table 1 Characteristics of the bacterial isolates included in the study [16,26] inducer (ESBL5)) [16] to evaluate the ability of the isolates to induce cytokines in the presence of three antibiotics (trimetoprim, ceftibuten and ciprofloxacin) representing three different antibiotic classes. The antimicrobial susceptibility testing showed that the isolates were resistant to all of the included antibiotics.…”

“…Antimicrobial susceptibility testing was performed as recommended by the Swedish Reference Group for Antibiotics (www.srga.org). The included ESBL-producing isolates have been characterized previously [16,26] and were all resistant to trimetoprim, ceftibuten and ciprofloxacin (all from SigmaeAldrich). A reference minimal inhibitory concentration (MIC) of trimetoprim, ceftibuten and ciprofloxacin was determined on two susceptible UPEC isolates.…”

“…The E. coli clone ST131 was detected using two ST131-specific pabB SNP assays by real-time PCR as previously described [31]. The ESBL isolates were genetically characterized for CTX-M, TEM and SHV type by real time PCR and nucleotide sequencing as previously described [26].…”