Dataset Information

New Klebsiella oxytoca beta-lactamase genes bla(OXY-3) and bla(OXY-4) and a third genetic group of K oxytoca based on bla(OXY-3).

ABSTRACT: The two genetic groups (oxy-1 and oxy-2) previously identified in the Klebsiella oxytoca taxon are recognizable by four independent molecular markers: (i). ERIC-1R profiles, (ii). 16S ribosomal DNA (rDNA) signature sequences, (iii). singular nucleotides in a defined fragment of the rpoB gene, and (iv) the type of the strain's bla(OXY) gene (i.e., bla(OXY-1) or bla(OXY-2)). K. oxytoca strains SG266 and SG271 could not be classified into these genetic groups based on their ERIC-1R profile and bla(OXY) gene sequence. With regard to the gene identity percentages between the bla(OXY-1) and bla(OXY-2) gene groups (86.8% +/- 0.4%) and within a bla(OXY) gene group (>99%), it was concluded that the bla(OXY) gene of strain SG271 was representative of a new bla(OXY) gene group (bla(OXY-3)), since the mean identity percentages between it and the two bla(OXY) gene groups were 85.5% +/- 0.2% and 84.4% +/- 0.4%, respectively. Since the corresponding percentages were 95.0% +/- 0.4% and 86.2% +/- 0.3% for strain SG266, it was impossible to classify its bla(OXY) gene, which was therefore named bla(OXY-4). The 16S rDNA signature sequences of the two strains could be determined only after cloning experiments. The SG266 clones displayed the same signature sequence as that of the genetic group oxy-1, whereas the SG271 clones displayed three different 16S rDNA signature sequences that also differed from those of the two genetic groups. Singular nucleotides were found within the rpoB sequence of the two strains, allowing for their distinction from the two genetic groups. All of these results, combined with those previously obtained by the ERIC-1R PCR method, indicate that strain SG271 is representative of a new K. oxytoca genetic group (oxy-3), whereas strain SG266 could not be classified.

SUBMITTER: Granier SA

PROVIDER: S-EPMC182611 | biostudies-literature | 2003 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

New Klebsiella oxytoca beta-lactamase genes bla(OXY-3) and bla(OXY-4) and a third genetic group of K oxytoca based on bla(OXY-3).

Granier Sophie A SA Leflon-Guibout Véronique V Goldstein Fred W FW Nicolas-Chanoine Marie-Hélène MH

Antimicrobial agents and chemotherapy 20030901 9

The two genetic groups (oxy-1 and oxy-2) previously identified in the Klebsiella oxytoca taxon are recognizable by four independent molecular markers: (i). ERIC-1R profiles, (ii). 16S ribosomal DNA (rDNA) signature sequences, (iii). singular nucleotides in a defined fragment of the rpoB gene, and (iv) the type of the strain's bla(OXY) gene (i.e., bla(OXY-1) or bla(OXY-2)). K. oxytoca strains SG266 and SG271 could not be classified into these genetic groups based on their ERIC-1R profile and bla( ...[more]

PMID: 12936995

Similar Datasets

Project description:Klebsiella oxytoca complex (KoC) species may overproduce their chromosomal class A OXY β-lactamases, conferring reduced susceptibility to piperacillin-tazobactam, expanded-spectrum cephalosporins and aztreonam. Moreover, since clavulanate maintains its ability to inhibit these enzymes, the resulting resistance phenotype may falsely resemble the production of acquired extended-spectrum β-lactamases (ESBLs). In this work, a collection of 44 KoC strains of human and animal origin was characterized with whole-genome sequencing (WGS) and broth microdilution (BMD) susceptibility testing. Comparison of ESBL producers (n = 11; including CTX-M-15 [n = 6] and CTX-M-1 [n = 5] producers) and hyperproducers of OXYs (n = 21) showed certain phenotypic differences: piperacillin-tazobactam (MIC90s: 16 versus >64 μg/mL), cefotaxime (MIC90s: 64 versus 4 μg/mL), ceftazidime (MIC90s: 32 versus 4 μg/mL), cefepime (MIC90s: 8 versus 4 μg/mL) and associated resistance to non-β-lactams (e.g., trimethoprim-sulfamethoxazole: 90.9% versus 14.3%, respectively). However, a clear phenotype-based distinction between the two groups was difficult. Therefore, we evaluated 10 different inhibitor-based confirmatory tests to allow such categorization. All tests showed a sensitivity of 100%. However, only combination disk tests (CDTs) with cefepime/cefepime-clavulanate and ceftazidime/ceftazidime-clavulanate or the double-disk synergy test (DDST) showed high specificity (100%, 95.5%, and 100%, respectively). All confirmatory tests in BMD or using the MIC gradient strip did not perform well (specificity, ≤87.5%). Of note, ceftazidime/ceftazidime-avibactam tests also exhibited low specificity (CDT, 87.5%; MIC gradient strip, 77.8%). Our results indicate that standard antimicrobial susceptibility profiles can raise some suspicion, but only the use of cefepime/cefepime-clavulanate CDT or DDST can guarantee distinction between ESBL-producing KoC strains and those hyperproducing OXY enzymes.

Dataset Information

New Klebsiella oxytoca beta-lactamase genes bla(OXY-3) and bla(OXY-4) and a third genetic group of K oxytoca based on bla(OXY-3).

Publications

New Klebsiella oxytoca beta-lactamase genes bla(OXY-3) and bla(OXY-4) and a third genetic group of K oxytoca based on bla(OXY-3).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets