scholarly journals Identification and Sequence of a tet(M) Tetracycline Resistance Determinant Homologue in Clinical Isolates of Escherichia coli

2006 ◽  
Vol 188 (20) ◽  
pp. 7151-7164 ◽  
Author(s):  
C. Hal Jones ◽  
Margareta Tuckman ◽  
Ellen Murphy ◽  
Patricia A. Bradford
Keyword(s):  
Escherichia Coli ◽  
Tetracycline Resistance ◽  
Mobile Element ◽  
Clinical Isolates ◽  
Resistance Determinant ◽  
M Gene ◽  
Insertion Element ◽  
E Coli ◽  
Vibrio Salmonicida ◽  
First Time

ABSTRACT The presence of the tetracycline resistance determinant tet(M) in human clinical isolates of Escherichia coli is described for the first time in this report. The homologue was >99% identical to the tet(M) genes reported to occur in Lactobacillus plantarum, Neisseria meningitidis, and Streptococcus agalactiae, and 3% of the residues in its deduced amino acid sequence diverge from tet(M) of Staphylococcus aureus. Sequence analysis of the regions immediately flanking the gene revealed that sequences upstream of tet(M) in E. coli have homology to Tn916; however, a complete IS26 insertion element was present immediately upstream of the promoter element. Downstream from the termination codon is an insertion sequence that was homologous to the ISVs1 element reported to occur in a plasmid from Vibrio salmonicida that has been associated with another tetracycline resistance determinant, tet(E). Results of mating experiments demonstrated that the E. coli tet(M) gene was on a mobile element so that resistance to tetracycline and minocycline could be transferred to a susceptible strain by conjugation. Expression of the cloned tet(M) gene, under the control of its own promoter, provided tetracycline and minocycline resistance to the E. coli host.

scholarly journals Constitutive soxR Mutations Contribute to Multiple-Antibiotic Resistance in Clinical Escherichia coli Isolates

2005 ◽  
Vol 49 (7) ◽  
pp. 2746-2752 ◽  
Author(s):  
Anastasia Koutsolioutsou ◽  
Samuel Peña-Llopis ◽  
Bruce Demple
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Dna Sequences ◽  
Single Point ◽  
Constitutive Expression ◽  
Clinical Isolates ◽  
Multiple Antibiotic Resistance ◽  
E Coli ◽  
First Time

ABSTRACT The soxRS regulon of Escherichia coli and Salmonella enterica is induced by redox-cycling compounds or nitric oxide and provides resistance to superoxide-generating agents, macrophage-generated nitric oxide, antibiotics, and organic solvents. We have previously shown that constitutive expression of soxRS can contribute to quinolone resistance in clinically relevant S. enterica. In this work, we have carried out an analysis of the mechanism of constitutive soxS expression and its role in antibiotic resistance in E. coli clinical isolates. We show that constitutive soxS expression in three out of six strains was caused by single point mutations in the soxR gene. The mutant SoxR proteins contributed to the multiple-antibiotic resistance phenotypes of the clinical strains and were sufficient to confer multiple-antibiotic resistance in a fresh genetic background. In the other three clinical isolates, we observed, for the first time, that elevated soxS expression was not due to mutations in soxR. The mechanism of such increased soxS expression remains unclear. The same E. coli clinical isolates harbored polymorphic soxR and soxS DNA sequences, also seen for the first time.

scholarly journals Regulation of P-Fimbrial Phase Variation Frequencies in Escherichia coli CFT073

2007 ◽  
Vol 75 (7) ◽  
pp. 3325-3334 ◽  
Author(s):  
Nicola Holden ◽  
Makrina Totsika ◽  
Lynn Dixon ◽  
Kirsteen Catherwood ◽  
David L. Gally
Keyword(s):  
Escherichia Coli ◽  
Phase Transition ◽  
Regulatory Region ◽  
Phase Variation ◽  
Culture Conditions ◽  
Host Tissue ◽  
Clinical Isolates ◽  
E Coli ◽  
K 12 ◽  
First Time

ABSTRACT Adherence of uropathogenic Escherichia coli to host tissue is required for infection and is mediated by fimbriae, such as pyelonephritis-associated pili (Pap). Expression of P fimbriae is regulated by phase variation, and to date, phase transition frequencies have been measured only for pap regulatory region constructs integrated into the E. coli K-12 chromosome. The aim of this work was to measure P phase transition frequencies in clinical isolates for the first time, including frequencies for the sequenced strain E. coli CFT073. P fimbriation and associated phase transition frequencies were measured for two E. coli clinical isolates and compared with levels for homologous pap constructs in E. coli K-12. Fimbriation and off-to-on transition frequencies were always higher in the clinical isolate. It was concluded that the regulatory inputs controlling papI expression are likely to be different in E. coli CFT073 and E. coli K-12 as (i) phase variation could be stimulated in E. coli K-12 by induction of papI and (ii) the level of expression of a papI::gfp + fusion was higher in E. coli CFT073 than in E. coli K-12. Furthermore, phase transition frequencies for the two E. coli CFT073 pap clusters were shown to be different depending on the culture conditions, indicating that there is a hierarchy of expression depending on signal inputs.

Prevalence of tetracycline resistance genes and identification of tet(M) in clinical isolates of Escherichia coli from sick ducks in China

2013 ◽  
Vol 62 (6) ◽  
pp. 851-858 ◽  
Author(s):  
Gong-Zheng Hu ◽  
Yu-Shan Pan ◽  
Hua Wu ◽  
Han Hu ◽  
Rui Xu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Genes ◽  
Promoter Region ◽  
Tetracycline Resistance ◽  
Resistance Rate ◽  
Clinical Isolates ◽  
Animal Origin ◽  
Broth Microdilution ◽  
M Gene ◽  
Tetracycline Resistance Genes

Tetracycline resistance is one of the most frequently encountered resistance properties in bacteria of animal origin. The aim of the present study was to investigate the prevalence and diversity of tetracycline resistance (tet) genes among Escherichia coli clinical isolates from diseased ducks in China and to report the identification and sequencing of the tet(M) gene. The susceptibility of 85 Escherichia coli strains to tetracyclines was determined by broth microdilution, and the presence of tet genes was investigated by multiplex PCR. All of the 85 isolates were fully resistant to both oxytetracycline and tetracycline, and 76.5 % were resistant to doxycycline. Seventy-seven of the isolates (90.6 %) encoded multiple tet genes, with 17.6, 38.8 and 34.1 % encoding two, three and four tet genes, respectively, and only 7.1 % encoded a single tet(A) gene. The MICs of oxytetracycline and tetracycline for all isolates ranged from 16 to ≥128 µg ml−1 with a MIC90 of >128 µg ml−1, regardless of the type or number of tet genes encoded. Isolates containing tet(M) commonly had more than one tet gene per strain. The doxycycline resistance rate in the tet(M)-positive isolates was significantly higher than in the tet(M)-negative isolates (P<0.05). A full-length tet(M) gene, including the promoter region, was obtained by PCR in seven of the 41 tet(M)-positive isolates and was sequenced and cloned. The cloned tet(M) gene conferred resistance to tetracyclines in the recombinant Escherichia coli host strain. These results revealed that, in these isolates, the prevalence of multiple tet genes was strikingly high and that tet(M) played a role in doxycycline resistance.

scholarly journals Emergence of Ertapenem Resistance in an Escherichia coli Clinical Isolate Producing Extended-Spectrum β-Lactamase AmpC

2011 ◽  
Vol 55 (9) ◽  
pp. 4443-4446 ◽  
Author(s):  
Hélène Guillon ◽  
Didier Tande ◽  
Hedi Mammeri
Keyword(s):  
Escherichia Coli ◽  
Bloodstream Infection ◽  
Clinical Isolate ◽  
Biochemical Characterization ◽  
Clinical Isolates ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
First Time

ABSTRACTEscherichia coliisolate MEV, responsible for a bloodstream infection, was resistant to penicillins, cephalosporins, and ertapenem. Molecular and biochemical characterization revealed the production of a novel, chromosome-borne, extended-spectrum AmpC (ESAC) β-lactamase with a Ser-282 duplication and increased carbapenemase activity. This study demonstrates for the first time that chromosome-borne ESAC β-lactamases can contribute to the emergence of ertapenem resistance inE. coliclinical isolates.

scholarly journals Piperacillin/tazobactam resistant, cephalosporin susceptible Escherichia coli bloodstream infections driven by multiple resistance mechanisms across diverse sequence types

2020 ◽  
Author(s):  
Thomas Edwards ◽  
Eva Heinz ◽  
Jon van Aartsen ◽  
Alex Howard ◽  
Paul Roberts ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bloodstream Infections ◽  
Tertiary Hospital ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Multiple Resistance ◽  
E Coli ◽  
Or Gene ◽  
First Time ◽  
Sequence Types

AbstractResistance to piperacillin/tazobactam in Escherichia coli is usually mediated by mechanisms providing resistance to 3rd generation cephalosporins, such as extended-spectrum β-lactamases and carbapenemases. Recent reports have identified E. coli strains with resistance to piperacillin/tazobactam but susceptibility to 3rd generation cephalosporins, achieved through hyperproduction of penicillinases, but the genetic diversity of this phenotype and the diversity of resistance mechanisms are unknown. We analysed the genomes of 63 clinical isolates of E. coli with this phenotype, isolated between 2014-2017 at a single tertiary hospital in Liverpool, UK. The phenotype was displayed in a broad range of sequence types which, after comparison with a UK-wide collection, reflected the overall diversity of E. coli clinical isolates. Resistance mechanisms were also diverse, and included predicted hyperproduction of penicillinases, either via strong promoters or gene amplification, carriage of inhibitor resistant β-lactamases, and an S133G blaCTX-M-15 mutation detected for the first time in clinical isolates.

Escherichia coli O157:H7 Cluster Associated With Deer Harvested at a Single Wildlife Hunting Area, Oregon, 2017

2021 ◽  
pp. 003335492110461
Author(s):  
Stephen G. Ladd-Wilson ◽  
Karim Morey ◽  
Lauren Turpen ◽  
Kara DeMarco ◽  
Gary Van Der Veen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Clinical Isolates ◽  
Escherichia Coli O157 ◽  
Nucleotide Polymorphisms ◽  
Additional Hypothesis ◽  
E Coli ◽  
Enteric Diseases ◽  
Lost To Follow Up ◽  
First Time

The Oregon Health Authority routinely investigates clusters of reportable enteric diseases identified by whole-genome sequencing. While investigating 2 cases of Escherichia coli O157:H7 in 2019, in which both patients were exposed to the same home-processed “jerky” and clinical isolates matched within 2 single nucleotide polymorphisms (SNPs), we discovered, by searching the National Library of Medicine’s National Center for Biotechnology Information website, 3 other cases of E coli O157:H7 from 3 Oregon counties—Tillamook, Umatilla, and Douglas—whose clinical isolates were within 9 SNPs of the 2 initial matched cases. We analyzed interview data for 3 case patients and followed up with additional hypothesis-generating questions. Onset of illness for the Tillamook, Umatilla, and Douglas county cases were October 7, 2017, October 27, 2017, and April 30, 2018, respectively. The median age of the 5 case patients was 16 years. Parents of 2 of the 5 case patients, each from a different county, had harvested deer approximately 20 miles from each other in the same Douglas County wildlife hunting unit in late September 2017. The case from Umatilla County was lost to follow-up. Although it is well documented that deer are a viable and substantial reservoir of E coli O157:H7, to our knowledge, this is the first time that venison from a common wildlife hunting unit was found to be associated with a cluster of illnesses. This finding suggests a geographic nidus for E coli O157:H7. We recommend routinely asking about wildlife hunting units when developing exposure hypotheses involving potential venison-associated clusters.

scholarly journals qnrA in CTX-M-Producing Escherichia coli Isolates from France

2006 ◽  
Vol 50 (12) ◽  
pp. 4224-4228 ◽  
Author(s):  
Jean-Philippe Lavigne ◽  
Hélène Marchandin ◽  
Julien Delmas ◽  
Nicole Bouziges ◽  
Evelyne Lecaillon ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Clinical Isolates ◽  
Class 1 Integron ◽  
E Coli ◽  
Extended Spectrum ◽  
Class 1 ◽  
First Time

ABSTRACT By PCR, we screened for qnr genes 112 clinical isolates of extended-spectrum β-lactamase-producing Escherichia coli collected from hospitals in France during 2004. For the first time, 7.7% of CTX-M-producing E. coli isolates presented a plasmid-mediated resistance to quinolones. All strains harbored a qnrA gene located on a sul1-type class 1 integron with similar structure to the In36 integron.

scholarly journals Detection of Carbapenem-Resistant Genes in Escherichia coli Isolated from Drinking Water in Khartoum, Sudan

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Neama Esmat Mahmoud ◽  
Hisham N. Altayb ◽  
Reem Majzoub Gurashi
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Treatment Options ◽  
Tetracycline Resistance ◽  
Carbapenem Resistance ◽  
High Rate ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Resistant Genes ◽  
First Time

Waterborne Escherichia coli are a major reservoir of antimicrobial resistance (AMR). Carbapenem-resistance, especially when mediated by transferable carbapenemase-encoding genes, is spreading worldwide and causing dramatically limiting treatment options. In our country, studies for the detection of carbapenem resistance in drinking water do not exist; therefore, this work was carried out to determine the prevalence of carbapenem-resistant genes “blaKPC, blaIMP, blaNDM, blaSPM, blaVIM, and blaOXA-48” among Escherichia coli isolated from drinking water in Khartoum, Sudan. A total of forty-five E. coli bacteria were isolated from different sources of drinking water. Antimicrobial susceptibility testing was performed using imipenem (10 mg/disc), gentamicin (10 mg/disc), ceftriaxone (30 mg/disc), ciprofloxacin (5 mg/disc), chloramphenicol (30 mg/disc), and tetracycline (30 mg/disc). “Sensitive” or “resistant” patterns of E. coli were judged using antibiotic minimum inhibitory concentration (MIC). Bacterial genomic DNA was extracted by the boiling method, and then multiplex polymerase chain reaction was performed to detect the carbapenemase genes (blaKPC, blaIMP, blaNDM, blaSPM, blaVIM, and blaOXA-48). Multiplex PCR assays confirmed the presence of carbapenemase genes in 28% of all water isolates. OXA-48 gene was the most predominant gene, detected in 15.5% of the isolates. The blaKPC and blaSPM genes were also detected in 4.4% and 8.8% of the isolates, respectively. However, the isolates were negative for blaNDM, blaVIM, and blaIMP genes. The isolates showed a high rate of tetracycline resistance (97.7%), followed by gentamicin (57.7%), ciprofloxacin (46.6%), ceftriaxone (35.5%), and chloramphenicol (31.1%). In conclusion, this study confirmed for the first time the presence of E. coli carried carbapenem-resistant genes in the drinking water of Khartoum state, Sudan. These isolates commonly carried OXA-48 (7/45), followed by SPM (4/45) and KPC (2/45).

Molecular Characterisation of ESBL producer E. coli

2018 ◽  
Vol 1 (2) ◽  
pp. 40-57
Author(s):  
Abdulghani Alsamarai ◽  
Shler Khorshed ◽  
Imad Weli
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Female Student ◽  
Clinical Problem ◽  
Clinical Isolates ◽  
Molecular Characterisation ◽  
M Gene ◽  
Esbl Producer ◽  
E Coli

Background: Antibiotic resistance emerged as clinical problem challenge the effective treatment of infections. Virulence factor may play an important role in the influence of antimicrobial resistance. Objective: To determine the frequency of resistance gene in E. coli clinical isolates from women with urinary tract infection. Materials and Methods: Fifteen E.coli clinical isolates were tested by PCR to determine their molecular characterization. Results: The bla CTX –M gene was not detected in 6.7% out of the tested 15 E. coli clinical isolates from women with urinary tract infection. However, bla OXA gene was detected in all E. coli tested clinical isolates from pregnant women, female student and diabetic women with urinary tract infection. While bla TEM gene and bla SHV gene were not detected in 33.3% and 40% out of the tested E. coli clinical isolates respectively. Conclusions: Four types of ESBL genes were detected, and shows new trend of distribution, which indicated the predominance of OXA and CTX-M genes.

scholarly journals Mechanistic insights into synergy between nalidixic acid and tetracycline against clinical isolates of Acinetobacter baumannii and Escherichia coli

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Amit Gaurav ◽  
Varsha Gupta ◽  
Sandeep K. Shrivastava ◽  
Ranjana Pathania
Keyword(s):  
Escherichia Coli ◽  
Acinetobacter Baumannii ◽  
Nalidixic Acid ◽  
Bacterial Infections ◽  
Clinical Isolates ◽  
Hospital Environment ◽  
Infection Model ◽  
Drug Resistant ◽  
E Coli

AbstractThe increasing prevalence of antimicrobial resistance has become a global health problem. Acinetobacter baumannii is an important nosocomial pathogen due to its capacity to persist in the hospital environment. It has a high mortality rate and few treatment options. Antibiotic combinations can help to fight multi-drug resistant (MDR) bacterial infections, but they are rarely used in the clinics and mostly unexplored. The interaction between bacteriostatic and bactericidal antibiotics are mostly reported as antagonism based on the results obtained in the susceptible model laboratory strain Escherichia coli. However, in the present study, we report a synergistic interaction between nalidixic acid and tetracycline against clinical multi-drug resistant A. baumannii and E. coli. Here we provide mechanistic insight into this dichotomy. The synergistic combination was studied by checkerboard assay and time-kill curve analysis. We also elucidate the mechanism behind this synergy using several techniques such as fluorescence spectroscopy, flow cytometry, fluorescence microscopy, morphometric analysis, and real-time polymerase chain reaction. Nalidixic acid and tetracycline combination displayed synergy against most of the MDR clinical isolates of A. baumannii and E. coli but not against susceptible isolates. Finally, we demonstrate that this combination is also effective in vivo in an A. baumannii/Caenorhabditis elegans infection model (p < 0.001)

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