scholarly journals Genotypic and phenotypic characterisation of the Klebsiella oxytoca complex

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Frazer McCuaig ◽  
Jody Winter ◽  
Jonathan Thomas ◽  
Gareth McVicker ◽  
Lesley Hoyles
Keyword(s):  
Klebsiella Oxytoca ◽  
Bloodstream Infections ◽  
Rare Condition ◽  
Clinical Isolates ◽  
Whole Genome Sequence ◽  
Beta Lactamases ◽  
Oxford Nanopore ◽  
Phenotypic Characterisation ◽  
Hybrid Genome ◽  
Extended Spectrum Beta Lactamases

Klebsiella spp. are associated with 3 to 7% of nosocomial infections and can be responsible for a range of conditions including pneumonia, bloodstream infections, meningitis, and necrotizing enterocolitis in infants. The role of Klebsiella pneumoniae in causing disease is well-characterised but, to date, the closely related species Klebsiella oxytoca has not received the same attention, despite often encoding extended-spectrum beta-lactamases and carbapenemases in clinical settings. K. oxytoca is the causative agent of Clostridiodes difficile-negative antibiotic-associated haemorrhagic colitis, a rare condition seen in some individuals receiving antibiotics. Whole-genome sequence analyses have shown K. oxytoca to be a complex comprising at least six species (K. oxytoca, K. michiganensis, K. grimontii, K. huaxiensis, ‘K. pasteurii’, ‘K. spallanzanii’). Our study aims to better characterise the K. oxytoca complex using a polyphasic approach. Preliminary investigations into the genomes of three K. michiganensis clinical isolates revealed the presence of a plasmid-borne ccdABlocus. ccdAB is a toxin-antitoxin (TA) system known to maintain plasmids in other pathogenic enterobacteria. We aim to functionally validate this TA system by cloning and conducting toxicity assays on the CcdB toxin, and cloning and assessing the ability of CcdA to function as an antidote. We also aim to sequence and generate Illumina/Oxford Nanopore hybrid genome assemblies of a larger collection of K. oxytoca complex clinical isolates and investigate their plasmids and TA systems in the same manner.

scholarly journals Molecular aspects of high-level resistance to sulbactam-cefoperazone in Klebsiella oxytoca clinical isolates.

1996 ◽  
Vol 40 (9) ◽  
pp. 1988-1994 ◽  
Author(s):  
K Kimura ◽  
Y Arakawa ◽  
S Ohsuka ◽  
H Ito ◽  
K Suzuki ◽  
...  
Keyword(s):  
Klebsiella Oxytoca ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Point Of View ◽  
Clinical Isolates ◽  
Beta Lactamase ◽  
Beta Lactamases ◽  
Molecular Aspects ◽  
High Level ◽  
Level Resistance

Nine Klebsiella oxytoca strains which demonstrated resistance to the combination of sulbactam and cefoperazone were isolated from geographically separate hospitals in Japan in 1995. Among them, K. oxytoca SB23 showed high-level resistance to sulbactam-cefoperazone (MIC > 128 micrograms/ml) and aztreonam (MIC, 128 micrograms/ml). The sulbactam-cefoperazone resistance was not transferred from strain SB23 to Escherichia coli CSH2 by conjugation, beta-Lactamase RbiA, produced by strain SB23, was purified, and the molecular mass was estimated to be 29 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Kinetic parameters for RbiA revealed that cefoperazone and aztreonam were hydrolyzed efficiently by this enzyme. Moreover, ceftazidime and imipenem were also hydrolyzed weakly by RbiA, although strain SB23 did not show any resistance to these agents. Clavulanate, sulbactam, and tazobactam failed to block the hydrolysis of cefoperazone by RbiA. The structural gene of RbiA (blaRBI) was cloned and sequenced, and the deduced amino acid sequence of RbiA demonstrated high-level similarities to those of the beta-lactamases found in K. oxytoca D488, E23004, and plasmid-mediated MEN-1, which have been classified into Bush functional group 2be. Although RbiA demonstrates high-level molecular similarity to the enzymes in group 2be, from an enzymological point of view, this enzyme might be differentiated from the enzymes in that group. Hybridization analysis revealed that beta-lactamase genes highly similar to blaRBI were generally encoded on the chromosome of the sulbactam-cefoperazone-resistant clinical isolates of K. oxytoca tested in the study, despite their different derivations. This observation suggests that sulbactam-cefoperazone-resistant A. oxytoca strains which produce RbiA-type beta-lactamases have been proliferating in many hospitals in Japan.

First Detection of OXA-10 Extended-Spectrum Beta-Lactamases and the Occurrence of mexR and nfxB in Clinical Isolates of Pseudomonas aeruginosa from Nigeria

Chemotherapy ◽  
2015 ◽  
Vol 61 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Bamidele T. Odumosu ◽  
Bola A. Adeniyi ◽  
Ram Chandra
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Clinical Isolates ◽  
Beta Lactamases ◽  
First Report ◽  
Extended Spectrum ◽  
Pcr Rflp ◽  
Extended Spectrum Beta Lactamases ◽  
Regulator Genes

Background: The characterization of β-lactamase production in Pseudomonasaeruginosa is rarely reported in Nigeria. The objective of this study was to investigate the occurrence and characterize the different β-lactamases as well as mechanisms of fluoroquinolones resistance among P. aeruginosa isolated from various clinical sources from Nigeria. Materials and Method: Isolates were investigated using PCR, RFLP and sequencing for the detection of various β-lactamases and efflux pump regulator genes. Result: The prevalence of OXA-10, AmpC, CTX-M and SHV in P. aeruginosa was 80, 70, 5 and 5%, respectively. The coexistence of blaOXA-10 with blaAmpC, blaSHV and blaCTX-M was reported in 40, 5 and 5% of isolates, respectively. The efflux pump regulator genes mexR and nfxB were both amplified in 45% of the OXA-10-positive isolates. Conclusion: This is the first report of the characterization of OXA-10 extended-spectrum β-lactamases and occurrence of mexR and nfxB efflux regulator genes in clinical isolates of P. aeruginosa in Nigeria.

scholarly journals Aminoglycoside-modifying enzymes in clinical isolates harboring extended-spectrum beta-lactamases.

1992 ◽  
Vol 36 (11) ◽  
pp. 2536-2538 ◽  
Author(s):  
A Fernandez-Rodriguez ◽  
R Canton ◽  
J C Perez-Diaz ◽  
J Martinez-Beltran ◽  
J J Picazo ◽  
...  
Keyword(s):  
Clinical Isolates ◽  
Beta Lactamases ◽  
Extended Spectrum ◽  
Extended Spectrum Beta Lactamases

scholarly journals Extended-spectrum beta-lactamases producing Escherichia coli and Klebsiella pneumoniaei: A Multi-centric Study Across Karnataka

2014 ◽  
Vol 6 (01) ◽  
pp. 007-013 ◽  
Author(s):  
Sridhar PN Rao ◽  
Prasad Subba Rama ◽  
Vishwanath Gurushanthappa ◽  
Radhakrishna Manipura ◽  
Krishna Srinivasan
Keyword(s):  
Escherichia Coli ◽  
Clinical Isolates ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Esbl Production ◽  
Beta Lactamases ◽  
E Coli ◽  
Karnataka State ◽  
Extended Spectrum Beta Lactamases ◽  
Esbl Producers

ABSTRACT Background: There are sporadic reports on detection of extended-spectrum beta-lactamases (ESBL) producers from Karnataka; hence, this is a first multicentric study across Karnataka state to determine the prevalence of ESBL production among clinical isolates of Escherichia coli and Klebsiella pneumoniaei. Aims and objectives: To determine the prevalence of ESBL producing clinical isolates of E. coli and K. pneumoniae from five geographically distributed centers across Karnataka, to study the susceptibility of ESBL producing isolates to other beta-lactam and beta-lactam-beta-lactamase inhibitors and to demonstrate transferability of plasmids coding for ESBL phenotype. Materials and Methods: Two hundred isolates of E. coli and K. pneumoniae each were collected from each of the five centers (Bellary, Dharwad, Davangere, Kolar and Mangalore). They were screened for resistance to screening agents (ceftazidime, cefotaxime, ceftriaxone, aztreonam) and positive isolates were confirmed for ESBL production by test described by Clinical and Laboratory Standards Institute . Co-production of ESBL and AmpC beta-lactamase was identified by using amino-phenylboronic acid disk method. Susceptibility of ESBL producers to beta-lactam antibiotics and beta-lactamase inhibitors was performed. Transferability of plasmids was performed by conjugation experiment. Results: Overall prevalence of ESBL production among E. coli and K. pneumoniae across five centers of the state was 57.5%. ESBL production was found to be 61.4% among E. coli and 46.2% among K. pneumoniae. ESBL production was significantly more among E. coli than K. pneumoniae. Significant variations in distribution of ESBL across the state was observed among E. coli isolates, but not among K. pneumoniae isolates. All ESBL producers demonstrated minimum inhibitory concentration levels ≥2 μg/ml towards cefotaxime, ceftazidime and ceftriaxone. Conclusion: Overall prevalence of ESBL production among clinical isolates of E. coli and K. pneumoniae across Karnataka state was high. The prevalence of ESBL production was significantly higher with E. coli than K. pneumoniae isolates. Higher rates of resistance to ceftriaxone and cefotaxime than to ceftazidime suggests the possibility of presence of CTX-M type ESBLs. Of all the beta-lactam/beta-lactamase inhibitor combinations tested, cefepime-tazobactam demonstrated highest in-vitro activity against ESBL producers. There was no statistical difference in the transferability of plasmids among E. coli and K. pneumoniae.

High Prevalence ofEscherichia coli-Producing CTX-M-15 Extended-Spectrum Beta-Lactamases in Poultry and Human Clinical Isolates in Romania

2015 ◽  
Vol 21 (6) ◽  
pp. 651-662 ◽  
Author(s):  
Iuliana E. Maciuca ◽  
Nicola J. Williams ◽  
Cristina Tuchilus ◽  
Olivia Dorneanu ◽  
Eleonora Guguianu ◽  
...  
Keyword(s):  
Ofescherichia Coli ◽  
Clinical Isolates ◽  
Beta Lactamases ◽  
Extended Spectrum ◽  
High Prevalence ◽  
Extended Spectrum Beta Lactamases

scholarly journals Molecular characterization of extended-spectrum beta-lactamases in Enterobacteriaceae from patients of two hospitals in Saxony, Germany

2007 ◽  
Vol 56 (2) ◽  
pp. 241-249 ◽  
Author(s):  
Joachim Schmitt ◽  
Enno Jacobs ◽  
Herbert Schmidt
Keyword(s):  
Plasmid Dna ◽  
Klebsiella Oxytoca ◽  
Rflp Analysis ◽  
Beta Lactamase ◽  
M Gene ◽  
Beta Lactamases ◽  
Extended Spectrum Beta Lactamase ◽  
Extended Spectrum ◽  
Genes Encoding ◽  
Extended Spectrum Beta Lactamases

Between January and September 2003, 39 isolates of the family Enterobacteriaceae with phenotypically positive Vitek 1 extended-spectrum beta-lactamase (ESBL) test results were collected, originating from patients of two hospitals in Saxony, Germany. Plasmid DNA was isolated and screened by PCR for the presence of genes encoding beta-lactamases of SHV, TEM and CTX-M types. To differentiate ESBL and non-ESBL among SHV and TEM genes, detailed analysis of PCR products was performed. Twenty-four strains carried SHV-2, SHV-5 or SHV-12 genes. In a further 11 strains a CTX-M gene was detected. The CTX-M genes could be affiliated to the CTX-M-1 and CTX-M-9 cluster by RFLP analysis. In the case of four Klebsiella oxytoca isolates, hyperproduction of the chromosomal beta-lactamase K1 was inferred, because genes of the above-mentioned types were not detected. The strains contained plasmid DNA between 45 and 160 kb in size. Common plasmid restriction patterns among SHV-5 producers provided evidence of horizontal spread. Twenty strains had a MIC for cefotaxime of ⩽4 mg l−1, 18 strains had the same MIC for ceftazidime, and nine strains had this MIC of >4 mg l−1 for both antibiotics. The ESBL phenotypes often coincided with ciprofloxacin or gentamicin resistance.

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