scholarly journals Gene Cluster Conferring Streptomycin, Sulfonamide, and Tetracycline Resistance inEscherichia coliO157:H7 Phage Types 23, 45, and 67

2011 ◽  
Vol 77 (5) ◽  
pp. 1900-1903 ◽  
Author(s):  
K. Ziebell ◽  
R. P. Johnson ◽  
A. M. Kropinski ◽  
R. Reid-Smith ◽  
R. Ahmed ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Gene Cluster ◽  
Tetracycline Resistance ◽  
Phage Types

ABSTRACTMultidrug resistance to streptomycin, sulfonamide, and tetracycline (AMR-SSuT) was identified in 156 of 171 isolates ofEscherichia coliO157:H7 of phage types 23, 45, and 67. In 154 AMR-SSuT isolates, resistance was encoded bystrA,strB,sul2, andtet(B), which in 59 of 63 tested isolates were found clustered together on the chromosome within thecdiAlocus.

scholarly journals Further tests of a recombination model in which chi removes the RecD subunit from the RecBCD enzyme of Escherichia coli.

Genetics ◽  
1990 ◽  
Vol 126 (3) ◽  
pp. 519-533 ◽  
Author(s):  
F W Stahl ◽  
L C Thomason ◽  
I Siddiqi ◽  
M M Stahl
Keyword(s):  
Escherichia Coli ◽  
Dna Sequence ◽  
Dna Packaging ◽  
Lambda Phage ◽  
Recombination Model ◽  
Phage Types ◽  
Point Of Entry ◽  
Reciprocal Recombination ◽  
Recbcd Enzyme ◽  
Lambda Dna

Abstract When one of two infecting lambda phage types in a replication-blocked cross is chi + and DNA packaging is divorced from the RecBCD-chi interaction, complementary chi-stimulated recombinants are recovered equally in mass lysates only if the chi + parent is in excess in the infecting parental mixture. Otherwise, the chi 0 recombinant is recovered in excess. This observation implies that, along with the chi 0 chromosome, two chi + parent chromosomes are involved in the formation of each chi + recombinant. The trimolecular nature of chi +-stimulated recombination is manifest in recombination between lambda and a plasmid. When lambda recombines with a plasmid via the RecBCD pathway, the resulting chromosome has an enhanced probability of undergoing lambda x lambda recombination in the interval into which the plasmid was incorporated. These two observations support a model in which DNA is degraded by Exo V from cos, the sequence that determines the end of packaged lambda DNA and acts as point of entry for RecBCD enzyme, to chi, the DNA sequence that stimulates the RecBCD enzyme to effect recombination. The model supposes that chi acts by ejecting the RecD subunit from the RecBCD enzyme with two consequences. (1) ExoV activity is blocked leaving a highly recombinagenic, frayed duplex end near chi, and (2) as the enzyme stripped of the RecD subunit travels beyond chi it is competent to catalyze reciprocal recombination.

scholarly journals Commensal Escherichia coli Antimicrobial Resistance and Multidrug-Resistance Dynamics during Broiler Growing Period: Commercial vs. Improved Farm Conditions

Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1005
Author(s):  
Laura Montoro-Dasi ◽  
Arantxa Villagra ◽  
Sandra Sevilla-Navarro ◽  
Maria Teresa Pérez-Gracia ◽  
Santiago Vega ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
Horizontal Resistance ◽  
Growing Period ◽  
Broiler Production ◽  
Field Level ◽  
Poultry Houses ◽  
Growing Conditions

New measures applied to reduce antimicrobial resistances (AMR) at field level in broiler production are focused on improving animals’ welfare and resilience. However, it is necessary to have better knowledge of AMR epidemiology. Thus, the aim of this study was to evaluate AMR and multidrug resistance (MDR) dynamics during the rearing of broilers under commercial (33 kg/m2 density and max. 20 ppm ammonia) and improved (17 kg/m2 density and max. 10 ppm ammonia) farm conditions. Day-old chicks were housed in two poultry houses (commercial vs. improved), and no antimicrobial agents were administered at any point. Animals were sampled at arrival day, mid-period and at slaughter day. High AMR rates were observed throughout rearing. No statistical differences were observed between groups. Moreover, both groups presented high MDR at slaughter day. These results could be explained by vertical or horizontal resistance acquisition. In conclusion, AMR and MDR are present throughout rearing. Moreover, although a lower level of MDR was observed at mid-period in animals reared under less intensive conditions, no differences were found at the end. In order to reduce the presence of AMR bacteria in poultry, further studies are needed to better understand AMR acquisition and prevalence in differing broiler growing conditions.

scholarly journals Genomic Characterization of New Variant of Hydrogen Sulfide (H2S)-Producing Escherichia coli with Multidrug Resistance Properties Carrying the mcr-1 Gene in China

Antibiotics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 80 ◽  
Author(s):  
Silpak Biswas ◽  
Mohammed Elbediwi ◽  
Guimin Gu ◽  
Min Yue
Keyword(s):  
Escherichia Coli ◽  
Hydrogen Sulfide ◽  
Multidrug Resistance ◽  
Bacterial Infections ◽  
Multidrug Resistant ◽  
Health Concern ◽  
Colistin Resistance ◽  
New Variant ◽  
Genomic Characterization ◽  
Human Infections

Colistin is considered to be a ‘last-resort’ antimicrobial for the treatment of multidrug-resistant Gram-negative bacterial infections. Identification of Enterobacteriaceae, carrying the transferable colistin resistance gene mcr-1, has recently provoked a global health concern. This report presents the first detection of a hydrogen sulfide (H2S)-producing Escherichia coli variant isolated from a human in China, with multidrug resistance (MDR) properties, including colistin resistance by the mcr-1 gene, which could have great implications for the treatment of human infections.

Large-scale production of citrate synthase from a cloned gene

1982 ◽  
Vol 60 (12) ◽  
pp. 1143-1147 ◽  
Author(s):  
Harry W. Duckworth ◽  
Alexander W. Bell
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Citrate Synthase ◽  
Specific Activity ◽  
Tetracycline Resistance ◽  
Scale Production ◽  
Ampicillin Resistance ◽  
Colicin E1 ◽  
Large Scale Production ◽  
Cloned Gene

Starting with a colicin E1 resistance recombinant plasmid which contains gltA, the gene for citrate synthase in Escherichia coli, we have constructed an ampicillin-resistance plasmid containing the gltA region as a 2.9-kilobase-pair insert in the tetracycline-resistance region of pBR322. Escherichia coli HB101 harbouring this plasmid, when grown on rich medium containing ampicillin, contains citrate synthase as about 8% of its soluble protein. The enzyme has been purified from this rich source and is identical to the chromosomal enzyme prepared previously in every property tested, except for specific activity, which is 64 U∙mg−1 as compared with 45–50 U∙mg−1 previously obtained. The N-terminal sequences of both enzymes are reported, and they are identical up to residue 16 at least. The overall yield of pure enzyme, starting with the cells grown in 15 L of medium, is 600–800 mg.

scholarly journals Molecular Characterization of a Multidrug Resistance IncF Plasmid from the Globally Disseminated Escherichia coli ST131 Clone

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0122369 ◽  
Author(s):  
Minh Duy Phan ◽  
Brian M. Forde ◽  
Kate M. Peters ◽  
Sohinee Sarkar ◽  
Steven Hancock ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Multidrug Resistance ◽  
Molecular Characterization ◽  
St131 Clone

scholarly journals Lambda Transducing Phage and Clones Carrying Genes of the cysJIHDC Gene Cluster of Escherichia coli K 12

Microbiology ◽  
1987 ◽  
Vol 133 (10) ◽  
pp. 2707-2717
Author(s):  
C. L. Hunt ◽  
V. Colless ◽  
M. T. Smith ◽  
D. O. Molasky ◽  
M. S. Malo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
K 12
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