Detection of genes encoding for virulence and adherence factors in Escherichia coli isolated in slaughtered Sarda breed sheep

ABSTRACTThe molecular epidemiology of 66 NDM-producing isolates from 2 Pakistani hospitals was investigated, with their genetic relatedness determined using repetitive sequence-based PCR (Rep-PCR). PCR-based replicon typing and screening for antibiotic resistance genes encoding carbapenemases, other β-lactamases, and 16S methylases were also performed. Rep-PCR suggested a clonal spread ofEnterobacter cloacaeandEscherichia coli. A number of plasmid replicon types were identified, with the incompatibility A/C group (IncA/C) being the most common (78%). 16S methylase-encoding genes were coharbored in 81% of NDM-producingEnterobacteriaceae.

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Shiga Toxins, and the Genes Encoding Them, in Fecal Samples from Native Idaho Ungulates

Applied and Environmental Microbiology ◽

10.1128/aem.01158-08 ◽

2008 ◽

Vol 75 (3) ◽

pp. 862-865 ◽

Cited By ~ 8

Author(s):

Jeremy J. Gilbreath ◽

Malcolm S. Shields ◽

Rebekah L. Smith ◽

Larry D. Farrell ◽

Peter P. Sheridan ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Wild Ungulates ◽

Fecal Samples ◽

Shiga Toxins ◽

Toxin Genes ◽

Genes Encoding ◽

Shiga Toxin Genes

ABSTRACT Cattle are a known reservoir of Shiga toxin-producing Escherichia coli. The prevalence and stability of Shiga toxin and/or Shiga toxin genes among native wild ungulates in Idaho were investigated. The frequency of both Shiga genes and toxin was similar to that reported for Idaho cattle (∼19%).

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PCR cloning, sequence analysis and expression of the cybC genes encoding soluble cytochrome b-562 from Escherichia coli B strain OP7 and K strain NM522

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/0005-2728(93)90223-3 ◽

1993 ◽

Vol 1143 (1) ◽

pp. 109-111 ◽

Cited By ~ 10

Author(s):

Michael K. Trower

Keyword(s):

Escherichia Coli ◽

Sequence Analysis ◽

Cytochrome B ◽

Pcr Cloning ◽

Genes Encoding ◽

Escherichia Coli B

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Characteristics of Shiga Toxin–Producing Escherichia coli Isolated from Swiss Raw Milk Cheese within a 3-Year Monitoring Program

Journal of Food Protection ◽

10.4315/0362-028x-73.1.88 ◽

2010 ◽

Vol 73 (1) ◽

pp. 88-91 ◽

Cited By ~ 36

Author(s):

C. ZWEIFEL ◽

N. GIEZENDANNER ◽

S. CORTI ◽

G. KRAUSE ◽

L. BEUTIN ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Monitoring Program ◽

Raw Milk ◽

Health Impact ◽

Toxin Gene ◽

Genes Encoding ◽

Raw Milk Cheese ◽

Human Infections ◽

Hard Cheese

Food is an important vehicle for transmission of Shiga toxin–producing Escherichia coli (STEC). To assess the potential public health impact of STEC in Swiss raw milk cheese produced from cow's, goat's, and ewe's milk, 1,422 samples from semihard or hard cheese and 80 samples from soft cheese were examined for STEC, and isolated strains were further characterized. By PCR, STEC was detected after enrichment in 5.7% of the 1,502 raw milk cheese samples collected at the producer level. STEC-positive samples comprised 76 semihard, 8 soft, and 1 hard cheese. By colony hybridization, 29 STEC strains were isolated from 24 semihard and 5 soft cheeses. Thirteen of the 24 strains typeable with O antisera belonged to the serogroups O2, O22, and O91. More than half (58.6%) of the 29 strains belonged to O:H serotypes previously isolated from humans, and STEC O22:H8, O91:H10, O91:H21, and O174:H21 have also been identified as agents of hemolytic uremic syndrome. Typing of Shiga toxin genes showed that stx1 was only found in 2 strains, whereas 27 strains carried genes encoding for the Stx2 group, mainly stx2 and stx2vh-a/b. Production of Stx2 and Stx2vh-a/b subtypes might be an indicator for a severe outcome in patients. Nine strains harbored hlyA (enterohemorrhagic E. coli hemolysin), whereas none tested positive for eae (intimin). Consequently, semihard and hard raw milk cheese may be a potential source of STEC, and a notable proportion of the isolated non-O157 STEC strains belonged to serotypes or harbored Shiga toxin gene variants associated with human infections.

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Ferric uptake regulator (Fur) reversibly binds a [2Fe-2S] cluster to sense intracellular iron homeostasis in Escherichia coli

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.014814 ◽

2020 ◽

Vol 295 (46) ◽

pp. 15454-15463 ◽

Cited By ~ 1

Author(s):

Chelsey R. Fontenot ◽

Homyra Tasnim ◽

Kathryn A. Valdes ◽

Codrina V. Popescu ◽

Huangen Ding

Keyword(s):

Escherichia Coli ◽

Iron Content ◽

Iron Homeostasis ◽

Ferric Uptake Regulator ◽

Intracellular Iron ◽

Free Iron ◽

E Coli ◽

Genes Encoding ◽

Fur Protein ◽

Mutant Cells

The ferric uptake regulator (Fur) is a global transcription factor that regulates intracellular iron homeostasis in bacteria. The current hypothesis states that when the intracellular “free” iron concentration is elevated, Fur binds ferrous iron, and the iron-bound Fur represses the genes encoding for iron uptake systems and stimulates the genes encoding for iron storage proteins. However, the “iron-bound” Fur has never been isolated from any bacteria. Here we report that the Escherichia coli Fur has a bright red color when expressed in E. coli mutant cells containing an elevated intracellular free iron content because of deletion of the iron–sulfur cluster assembly proteins IscA and SufA. The acid-labile iron and sulfide content analyses in conjunction with the EPR and Mössbauer spectroscopy measurements and the site-directed mutagenesis studies show that the red Fur protein binds a [2Fe-2S] cluster via conserved cysteine residues. The occupancy of the [2Fe-2S] cluster in Fur protein is ∼31% in the E. coli iscA/sufA mutant cells and is decreased to ∼4% in WT E. coli cells. Depletion of the intracellular free iron content using the membrane-permeable iron chelator 2,2´-dipyridyl effectively removes the [2Fe-2S] cluster from Fur in E. coli cells, suggesting that Fur senses the intracellular free iron content via reversible binding of a [2Fe-2S] cluster. The binding of the [2Fe-2S] cluster in Fur appears to be highly conserved, because the Fur homolog from Hemophilus influenzae expressed in E. coli cells also reversibly binds a [2Fe-2S] cluster to sense intracellular iron homeostasis.

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Selective cloning of genes encoding RNase H from Salmonella typhimurium, Saccharomyces cerevisiae and Escherichia coli rnh mutant

MGG Molecular & General Genetics ◽

10.1007/bf00273935 ◽

1991 ◽

Vol 227 (3) ◽

pp. 438-445 ◽

Cited By ~ 40

Author(s):

Mitsuhiro Itaya ◽

Dorothy McKelvin ◽

Sunil K. Chatterjie ◽

Robert J. Crouch

Keyword(s):

Escherichia Coli ◽

Saccharomyces Cerevisiae ◽

Salmonella Typhimurium ◽

Rnase H ◽

Genes Encoding

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Detection and Quantification of Superoxide Formed within the Periplasm of Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.00554-06 ◽

2006 ◽

Vol 188 (17) ◽

pp. 6326-6334 ◽

Cited By ~ 111

Author(s):

Sergei Korshunov ◽

James A. Imlay

Keyword(s):

Escherichia Coli ◽

Pathogenic Bacteria ◽

Phagocytic Cells ◽

Free Living ◽

E Coli ◽

Superoxide Formation ◽

Genes Encoding ◽

Copper Zinc ◽

Primary Substrate

ABSTRACT Many gram-negative bacteria harbor a copper/zinc-containing superoxide dismutase (CuZnSOD) in their periplasms. In pathogenic bacteria, one role of this enzyme may be to protect periplasmic biomolecules from superoxide that is released by host phagocytic cells. However, the enzyme is also present in many nonpathogens and/or free-living bacteria, including Escherichia coli. In this study we were able to detect superoxide being released into the medium from growing cultures of E. coli. Exponential-phase cells do not normally synthesize CuZnSOD, which is specifically induced in stationary phase. However, the engineered expression of CuZnSOD in growing cells eliminated superoxide release, confirming that this superoxide was formed within the periplasm. The rate of periplasmic superoxide production was surprisingly high and approximated the estimated rate of cytoplasmic superoxide formation when both were normalized to the volume of the compartment. The rate increased in proportion to oxygen concentration, suggesting that the superoxide is generated by the adventitious oxidation of an electron carrier. Mutations that eliminated menaquinone synthesis eradicated the superoxide formation, while mutations in genes encoding respiratory complexes affected it only insofar as they are likely to affect the redox state of menaquinone. We infer that the adventitious autoxidation of dihydromenaquinone in the cytoplasmic membrane releases a steady flux of superoxide into the periplasm of E. coli. This endogenous superoxide may create oxidative stress in that compartment and be a primary substrate of CuZnSOD.

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