scholarly journals ISKpn40-Mediated Mobilization of the Colistin Resistance Gene mcr-3.11 in Escherichia coli

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Yu-Zhang He ◽  
Teng-Fei Long ◽  
Cai-Ping Chen ◽  
Bing He ◽  
Xing-Ping Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Gene ◽  
Wild Type ◽  
Colistin Resistance ◽  
Content Type ◽  
First Report ◽  
E Coli ◽  
Target Sites

ABSTRACT The mobile colistin resistance gene mcr-3 has globally disseminated since it was first reported in 2017 in Escherichia coli. In vitro mobilization assays in this study demonstrate the functionality of the composite transposon structure ISKpn40-mcr-3.11-dgkA-ISKpn40 in wild-type and recA− E. coli strains. These transpositions generated 4-bp duplications at the target sites. This is the first report demonstrating the mobility of the mcr-3.11 gene by transposition.

scholarly journals Emergence of Colistin Resistance Gene mcr-1 in Cronobacter sakazakii Producing NDM-9 and in Escherichia coli from the Same Animal

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Bao-Tao Liu ◽  
Feng-Jing Song ◽  
Ming Zou ◽  
Zhi-Hui Hao ◽  
Hu Shan
Keyword(s):  
Escherichia Coli ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Cronobacter Sakazakii ◽  
Colistin Resistance ◽  
Content Type ◽  
E Coli ◽  
Carbapenem Resistant

ABSTRACT We report the presence of mcr-1 in Escherichia coli and carbapenem-resistant Cronobacter sakazakii from the same diseased chicken. The mcr-1 gene linked with ISApl1 was located on two different IncI2 plasmids, including one multidrug plasmid in E. coli, whereas fosA3-bla NDM-9 was on an IncB/O plasmid in C. sakazakii. The development of the fosA3-bla NDM-9 resistance region was mediated by IS26. The colocation of mcr-1 or bla NDM-9 with other resistance genes will accelerate the dissemination of the two genes.

scholarly journals Activity of Tigecycline or Colistin in Combination with Zidovudine against Escherichia coli Harboring tet(X) and mcr-1

2020 ◽  
Vol 65 (1) ◽  
pp. e01172-20 ◽  
Author(s):  
Yu-Feng Zhou ◽  
Ping Liu ◽  
Shu-He Dai ◽  
Jian Sun ◽  
Ya-Hong Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistant ◽  
Therapeutic Options ◽  
Infection Model ◽  
Synergistic Activity ◽  
Colistin Resistance ◽  
Content Type ◽  
E Coli ◽  
Antiretroviral Drug

ABSTRACTAlternative therapeutic options are urgently needed against multidrug-resistant Escherichia coli infections, especially in situations of preexisting tigecycline and colistin resistance. Here, we investigated synergistic activity of the antiretroviral drug zidovudine in combination with tigecycline or colistin against E. coli harboring tet(X) and mcr-1 in vitro and in a murine thigh infection model. Zidovudine and tigecycline/colistin combinations achieved synergistic killing and significantly decreased bacterial burdens by >2.5-log10 CFU/g in thigh tissues compared to each monotherapy.

scholarly journals Occurrence and Genomic Characterization of Two MCR-1-Producing Escherichia coli Isolates from the Same Mink Farmer

mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Beiwen Zheng ◽  
Hao Xu ◽  
Chen Huang ◽  
Xiao Yu ◽  
Lihua Guo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Gene ◽  
Animal Health ◽  
Molecular Characteristics ◽  
Colistin Resistance ◽  
Public Health Importance ◽  
Content Type ◽  
E Coli ◽  
Human Interface ◽  
Healthy Humans

ABSTRACT The spread of colistin resistance gene mcr-1 at the animal-human interface remains largely unknown. This work aimed to investigate the molecular characteristics of two extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli strains with mcr-1, i.e., strains H8 and H9, isolated from the same mink farmer. In this study, five mcr-positive E. coli strains were isolated from the mink farm. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) identified two genetically unrelated MCR-1 producers (H8 and H9) from the same farmer and two clonally related MCR-1-positive isolates (M5 and M6) from two different mink samples. Additionally, a mcr-1 variant, designated mcr-1.12, was identified in isolate M4. MIC determination revealed that all of the MCR-producing strains exhibited multiresistant phenotypes but showed susceptibility to imipenem, meropenem, amikacin, and tigecycline. Replicon typing showed that mcr-1 was associated with IncHI2 plasmids in 4 cases, while the gene was located on an IncI2 plasmid in 1 case. PacBio sequencing and plasmid analysis confirmed that the mcr-1 gene was located on an ∼204-kb IncHI2 plasmid in H8 and was carried by an ∼61-kb IncI2 plasmid in H9. To our knowledge, this work represents the first report of the occurrence of MCR-producing isolates from mink. Moreover, our report also describes the coexistence of two different MCR-1 producers in the same farmer. It highlights that fur farms can be reservoirs of mcr-1 genes. The identification of mcr-carrying plasmids on a fur farm is of potential public health importance, as it suggests that mcr is widespread in the animal husbandry industry. IMPORTANCE Colistin resistance is a real threat for both human and animal health. The mobile colistin resistance gene mcr has contributed to the persistence and transmission of colistin resistance at the interfaces of animals, humans, and ecosystems. Although mcr genes have usually been recovered from food animals, patients, and healthy humans, transmission of mcr genes at the animal-human interface remains largely unknown. This was the first study to isolate and characterize MCR-producing isolates from mink, as well as to report the coexistence of two different MCR-1 producers in the same farmer. The characterization and analysis of two MCR-1-producing E. coli isolates may have important implications for comprehension of the transmission dynamics of these bacteria. We emphasize the importance of improved multisectorial surveillance of colistin-resistant E. coli in this region.

scholarly journals Antimicrobial Activity Evaluation of Tebipenem (SPR859), an Orally Available Carbapenem, against a Global Set of Enterobacteriaceae Isolates, Including a Challenge Set of Organisms

2019 ◽  
Vol 63 (6) ◽  
Author(s):  
S. J. Ryan Arends ◽  
Paul R. Rhomberg ◽  
Nicole Cotroneo ◽  
Aileen Rubio ◽  
Robert K. Flamm ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Activity ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Broth Microdilution ◽  
Wild Type ◽  
Content Type ◽  
E Coli

ABSTRACT The antimicrobial activity of tebipenem and other carbapenem agents were tested in vitro against a set of recent clinical isolates responsible for urinary tract infection (UTI), as well as against a challenge set. Isolates were tested by reference broth microdilution and included Escherichia coli (101 isolates), Klebsiella pneumoniae (208 isolates), and Proteus mirabilis (103 isolates) species. Within each species tested, tebipenem showed equivalent MIC50/90 values to those of meropenem (E. coli MIC50/90, ≤0.015/0.03 mg/liter; K. pneumoniae MIC50/90, 0.03/0.06 mg/liter; and P. mirabilis MIC50/90, 0.06/0.12 mg/liter) and consistently displayed MIC90 values 8-fold lower than imipenem. Tebipenem and meropenem (MIC50, 0.03 mg/liter) showed equivalent MIC50 results against wild-type, AmpC-, and/or extended-spectrum β-lactamase (ESBL)-producing isolates. Tebipenem also displayed MIC50/90 values 4- to 8-fold lower than imipenem against the challenge set. All carbapenem agents were less active (MIC50, ≥8 mg/liter) against isolates carrying carbapenemase genes. These data confirm the in vitro activity of the orally available agent tebipenem against prevalent UTI Enterobacteriaceae species, including those producing ESBLs and/or plasmid AmpC enzymes.

scholarly journals Various Sequence Types of Escherichia coli Isolates Coharboring blaNDM-5 and mcr-1 Genes from a Commercial Swine Farm in China

2016 ◽  
Vol 61 (3) ◽  
Author(s):  
Ling-Han Kong ◽  
Chang-Wei Lei ◽  
Su-Zhen Ma ◽  
Wei Jiang ◽  
Bi-Hui Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Resistance Gene ◽  
Genome Sequencing ◽  
Carbapenem Resistance ◽  
Whole Genome ◽  
Swine Farm ◽  
Colistin Resistance ◽  
Content Type ◽  
E Coli ◽  
Sequence Types

ABSTRACT Sixteen different sequence types (STs) of Escherichia coli isolates from a commercial swine farm in China were confirmed to coharbor the carbapenem resistance gene bla NDM-5 and the colistin resistance gene mcr-1. Whole-genome sequencing revealed that bla NDM-5 and mcr-1 were located on a 46-kb IncX3 plasmid and a 32-kb IncX4 plasmid, respectively. The two plasmids can transfer together with a low fitness cost, which might explain the presence of various STs of E. coli coharboring bla NDM-5 and mcr-1.

scholarly journals Detection of themcr-1Colistin Resistance Gene in Carbapenem-Resistant Enterobacteriaceae from Different Hospitals in China

2016 ◽  
Vol 60 (8) ◽  
pp. 5033-5035 ◽  
Author(s):  
Hua Yu ◽  
Fen Qu ◽  
Bin Shan ◽  
Bin Huang ◽  
Wei Jia ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Global Health ◽  
Resistance Gene ◽  
Clinical Isolates ◽  
Chromosomal Integration ◽  
Colistin Resistance ◽  
Content Type ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Carbapenem Resistant Enterobacteriaceae

ABSTRACTThe spread of the plasmid-mediated colistin resistance gene,mcr-1, into carbapenem-resistantEnterobacteriaceae(CRE) clinical isolates poses a significant threat to global health. Here we report the identification of threemcr-1-harboring carbapenem-resistantEscherichia colistrains, collected from three patients in two provinces in China. Our results show thatmcr-1-harboring CRE strains have started to spread in different hospitals in China. In addition, this report presents the first description of chromosomal integration ofmcr-1into a carbapenem-resistantE. colistrain.

scholarly journals Finding Regulators Associated with the Expression of the Long Polar Fimbriae in Enteropathogenic Escherichia coli

2015 ◽  
Vol 197 (23) ◽  
pp. 3658-3665 ◽  
Author(s):  
Jia Hu ◽  
Brittany N. Ross ◽  
Roberto J. Cieza ◽  
Alfredo G. Torres
Keyword(s):  
Escherichia Coli ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Content Type ◽  
E Coli ◽  
Colonization Factor ◽  
Initial Adhesion ◽  
Intestinal Adhesion

ABSTRACTEnteropathogenicEscherichia coli(EPEC) is a human pathogen that requires initial adhesion to the intestine in order to cause disease. Multiple adhesion factors have been identified inE. colistrains, among them the long polar fimbriae (Lpf), a colonization factor associated with intestinal adhesion. The conditions of Lpf expression are well understood in enterohemorrhagicE. coli(EHEC); however, the expression of EPEClpfhas been found to be repressed under anyin vitrocondition tested. Therefore, we decided to identify those factors silencing expression of EPEClpf. Because histone-like nucleoid structuring protein (H-NS) is a known repressor of EHEClpf, we tested it and found that H-NS is a repressor of EPEClpf. We also found that the adhesion of the EPEC Δhnsstrain was significantly enhanced compared to the wild-type strain. Becauselpfexpression was modestly increased in thehnsmutant, transposon mutagenesis was performed to find a strain displaying higherlpfexpression than EPEC Δhns. One Tn5insertion was identified within theyhjXgene, and furtherin vitrocharacterization revealed increasedlpfexpression and adhesion to Caco-2 cells compared with EPEC Δhns. However, in a murine model of intestinal infection, the EPEC Δhnsand EPEC ΔhnsTn5mutants had only a slight change in colonization pattern compared to the wild-type strain. Our data showed that EPEC Lpf is transcribed, but its role in EPEC intestinal colonization requires further analysis.IMPORTANCEData are presented demonstrating that the long polar fimbriae (lpf) operon in enteropathogenicE. coli(EPEC) is highly regulated; however, derepression occurs by mutagenizing two proteins associated with its control. The study demonstrates that the EPEClpfoperon can be expressed and, therefore, participates in the EPEC adherence phenotype.

scholarly journals Structure and Mutational Analyses of Escherichia coli ZapD Reveal Charged Residues Involved in FtsZ Filament Bundling

2016 ◽  
Vol 198 (11) ◽  
pp. 1683-1693 ◽  
Author(s):  
Elyse J. Roach ◽  
Charles Wroblewski ◽  
Laura Seidel ◽  
Alison M. Berezuk ◽  
Dyanne Brewer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Bacterial Cell ◽  
Site Directed Mutagenesis ◽  
Bacterial Cell Division ◽  
Wild Type ◽  
Content Type ◽  
E Coli ◽  
Z Ring

ABSTRACTBacterial cell division is an essential and highly coordinated process. It requires the polymerization of the tubulin homologue FtsZ to form a dynamic ring (Z-ring) at midcell. Z-ring formation relies on a group of FtsZ-associatedproteins (Zap) for stability throughout the process of division. InEscherichia coli, there are currently five Zap proteins (ZapA through ZapE), of which four (ZapA, ZapB, ZapC, and ZapD) are small soluble proteins that act to bind and bundle FtsZ filaments. In particular, ZapD forms a functional dimer and interacts with the C-terminal tail of FtsZ, but little is known about its structure and mechanism of action. Here, we present the crystal structure ofEscherichia coliZapD and show it forms a symmetrical dimer with centrally located α-helices flanked by β-sheet domains. Based on the structure of ZapD and its chemical cross-linking to FtsZ, we targeted nine charged ZapD residues for modification by site-directed mutagenesis. Usingin vitroFtsZ sedimentation assays, we show that residues R56, R221, and R225 are important for bundling FtsZ filaments, while transmission electron microscopy revealed that altering these residues results in different FtsZ bundle morphology compared to those of filaments bundled with wild-type ZapD. ZapD residue R116 also showed altered FtsZ bundle morphology but levels of FtsZ bundling similar to that of wild-type ZapD. Together, these results reveal that ZapD residues R116, R221, and R225 likely participate in forming a positively charged binding pocket that is critical for bundling FtsZ filaments.IMPORTANCEZ-ring assembly underpins the formation of the essential cell division complex known as the divisome and is required for recruitment of downstream cell division proteins. ZapD is one of several proteins inE. colithat associates with the Z-ring to promote FtsZ bundling and aids in the overall fitness of the division process. In the present study, we describe the dimeric structure ofE. coliZapD and identify residues that are critical for FtsZ bundling. Together, these results advance our understanding about the formation and dynamics of the Z-ring prior to bacterial cell division.

scholarly journals A Rhodobacter sphaeroides Protein Mechanistically Similar to Escherichia coli DksA Regulates Photosynthetic Growth

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Christopher W. Lennon ◽  
Kimberly C. Lemmer ◽  
Jessica L. Irons ◽  
Max I. Sellman ◽  
Timothy J. Donohue ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Structure Function ◽  
Rhodobacter Sphaeroides ◽  
Fatty Acid Content ◽  
Regulatory Protein ◽  
Growth Conditions ◽  
Globular Domain ◽  
Content Type ◽  
E Coli

ABSTRACTDksA is a global regulatory protein that, together with the alarmone ppGpp, is required for the “stringent response” to nutrient starvation in the gammaproteobacteriumEscherichia coliand for more moderate shifts between growth conditions. DksA modulates the expression of hundreds of genes, directly or indirectly. Mutants lacking a DksA homolog exhibit pleiotropic phenotypes in other gammaproteobacteria as well. Here we analyzed the DksA homolog RSP2654 in the more distantly relatedRhodobacter sphaeroides, an alphaproteobacterium. RSP2654 is 42% identical and similar in length toE. coliDksA but lacks the Zn finger motif of theE. coliDksA globular domain. Deletion of the RSP2654 gene results in defects in photosynthetic growth, impaired utilization of amino acids, and an increase in fatty acid content. RSP2654 complements the growth and regulatory defects of anE. colistrain lacking thedksAgene and modulates transcriptionin vitrowithE. coliRNA polymerase (RNAP) similarly toE. coliDksA. RSP2654 reduces RNAP-promoter complex stabilityin vitrowith RNAPs fromE. coliorR. sphaeroides, alone and synergistically with ppGpp, suggesting that even though it has limited sequence identity toE. coliDksA (DksAEc), it functions in a mechanistically similar manner. We therefore designate the RSP2654 protein DksARsp. Our work suggests that DksARsphas distinct and important physiological roles in alphaproteobacteria and will be useful for understanding structure-function relationships in DksA and the mechanism of synergy between DksA and ppGpp.IMPORTANCEThe role of DksA has been analyzed primarily in the gammaproteobacteria, in which it is best understood for its role in control of the synthesis of the translation apparatus and amino acid biosynthesis. Our work suggests that DksA plays distinct and important physiological roles in alphaproteobacteria, including the control of photosynthesis inRhodobacter sphaeroides. The study of DksARsp, should be useful for understanding structure-function relationships in the protein, including those that play a role in the little-understood synergy between DksA and ppGpp.

scholarly journals Enhancement of the Efficiency of Secretion of Heterologous Lipase in Escherichia coli by Directed Evolution of the ABC Transporter System

2005 ◽  
Vol 71 (7) ◽  
pp. 3468-3474 ◽  
Author(s):  
Gyeong Tae Eom ◽  
Jae Kwang Song ◽  
Jung Hoon Ahn ◽  
Yeon Soo Seo ◽  
Joon Shick Rhee
Keyword(s):  
Escherichia Coli ◽  
Directed Evolution ◽  
Abc Transporter ◽  
Microtiter Plate ◽  
Single Amino Acid ◽  
Wild Type ◽  
E Coli ◽  
Single Amino Acid Change ◽  
Secretion Efficiency

ABSTRACT The ABC transporter (TliDEF) from Pseudomonas fluorescens SIK W1, which mediated the secretion of a thermostable lipase (TliA) into the extracellular space in Escherichia coli, was engineered using directed evolution (error-prone PCR) to improve its secretion efficiency. TliD mutants with increased secretion efficiency were identified by coexpressing the mutated tliD library with the wild-type tliA lipase in E. coli and by screening the library with a tributyrin-emulsified indicator plate assay and a microtiter plate-based assay. Four selected mutants from one round of error-prone PCR mutagenesis, T6, T8, T24, and T35, showed 3.2-, 2.6-, 2.9-, and 3.0-fold increases in the level of secretion of TliA lipase, respectively, but had almost the same level of expression of TliD in the membrane as the strain with the wild-type TliDEF transporter. These results indicated that the improved secretion of TliA lipase was mediated by the transporter mutations. Each mutant had a single amino acid change in the predicted cytoplasmic regions in the membrane domain of TliD, implying that the corresponding region of TliD was important for the improved and successful secretion of the target protein. We therefore concluded that the efficiency of secretion of a heterologous protein in E. coli can be enhanced by in vitro engineering of the ABC transporter.

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