Search results for "Escher"
showing 10 items of 728 documents
In vivo effects of intravascularly applied Escherichia coli hemolysin: dissociation between induction of granulocytopenia and lethality in monkeys.
1993
The effects of intravascular application of endotoxin-depleted Escherichia coli hemolysin (HlyA) was studied in rabbits and monkeys. In rabbits, bolus application of HlyA calculated to effect final blood levels of approximately 2-3 HU/ml (200-300 ng/ml) caused an acute fall of polymorphonuclear blood leukocytes to less than 20% of starting levels within 5 min. Additionally, platelet counts dropped to approximately 30% of starting levels, whereas lymphocyte counts varied considerably and seldom fell to less than 50%. Nine out ten animals that received 2-4 HU/ml toxin died within 90 min post application. These animals presented with signs of acute respiratory failure and post mortem inspectio…
Sepsis due to Erysipelothrix rhusiopathiae in a Patient with Chronic Lymphocytic Leukemia Associated with Bronchopneumonia due to PSeudomonas aerugin…
2015
Erysipelothrix rhusiopathiae infections can typically be attributed to exposure to animal products; thus, these infections are more common among farmers, butchers and veterinarians, among others. This article describes a case involving a 54-year-old man who had relative neutropenia subsequent to treatment for chronic lymphocytic leukemia. The patient developed E rhusiopathiae bacteremia with concomitant pneumonia. The author of this article suggests a likely route of infection, which is atypical considering the patient did not report exposure to animal products.
Specific DNA probes to detect Escherichia coli strains producing cytotoxic necrotising factor type 1 or type 2
1994
Cytotoxic necrotising factors type 1 (CNF1) and type 2 (CNF2) are produced by many Escherichia coli strains isolated from man and animals with intestinal or extra-intestinal colibacillosis. In most laboratories, CNF-producing strains are detected by a cell cytotoxicity assay and confirmed with a neutralisation assay or a mouse footpad assay. In this study, we sought to determine whether DNA probes could detect clinical isolates of E. coli producing CNF2 or CNF1, or both, without the need for cell cultures or animal assays. Two internal fragments of the gene encoding CNF2 were used as DNA probes: a 875-bp XhoI-PstI DNA fragment and an adjacent 335-bp PstI-ClaI fragment. A positive response w…
Sensing by the membrane-bound sensor kinase DcuS: exogenous versus endogenous sensing of C(4)-dicarboxylates in bacteria.
2010
Bacteria are able to grow at the expense of both common (succinate, L-malate, fumarate and aspartate) and uncommon (L-tartrate and D-malate) C4-dicarboxylates, which are components of central metabolism. Two types of sensors/regulators responding to the C4-dicarboxylates function in Escherichia coli, Bacillus, Lactobacillus and related bacteria. The first type represents membrane-integral two-component systems, while the second includes cytoplasmic LysR-type transcriptional regulators. The difference in location and substrate specificity allows the exogenous induction of metabolic genes by common C4-dicarboxylates, and endogenous induction by uncommon C4-dicarboxylates. The two-component s…
Quantification of denitrifying bacteria in soils by nirK gene targeted real-time PCR.
2004
Abstract Denitrification, the reduction of nitrate to nitrous oxide or dinitrogen, is the major biological mechanism by which fixed nitrogen returns to the atmosphere from soil and water. Microorganisms capable of denitrification are widely distributed in the environment but little is known about their abundance since quantification is performed using fastidious and time-consuming MPN-based approaches. We used real-time PCR to quantify the denitrifying nitrite reductase gene (nirK), a key enzyme of the denitrifying pathway catalyzing the reduction of soluble nitrogen oxide to gaseous form. The real-time PCR assay was linear over 7 orders of magnitude and sensitive down to 102 copies by assa…
Bactericidal activity of human milk: stability during storage
2016
Human milk provides infants with defensive factors against many illnesses. This study aims to analyse global bactericidal activity in fresh human milk and evaluate its stability in relation to milk manipulation and its possible alteration following refrigeration. Nineteen milk samples (mature milk) from 19 healthy women are analysed. Viability testing involving a strain of Escherichia coli NCTC 9111, serovar O111:K58(B4):H- was used to determine the bactericidal effect of human milk. Degree of bacteriolysis is calculated as the difference between E. coli counts in controls and in milk samples, expressed as a percentage of the control sample counts. An evaluation of the effect of refrigerati…
Outbreak of colonizations by extended-spectrum β-lactamase-producing Escherichia coli sequence type 131 in a neonatal intensive care unit, Italy
2013
Abstract Background Extended spectrum β-lactamases (ESBLs) often associated with resistance to aminoglycosides and fluoroquinolones have recently emerged in community-associated Escherichia coli. The worldwide clonal dissemination of E. coli sequence type (ST)131 is playing a prominent role. We describe an outbreak of colonizations by ESBL-producing E. coli (ESBL-E. coli) in the neonatal intensive care unit (NICU) of the University Hospital, Palermo, Italy. Methods An epidemiological investigation was conducted with the support of molecular typing. All children admitted to the NICU and colonized by ESBL-E. coli between January and June 2012, were included in the study. Cases were defined as…
Conversion of the Sensor Kinase DcuS to the Fumarate Sensitive State by Interaction of the Bifunctional Transporter DctA at the TM2/PAS
2021
The membrane-bound C4-dicarboxylate (C4DC) sensor kinase DcuS of Escherichia coli typically forms a protein complex with the C4DC transporter DctA. The DctA × DcuS complex is able to respond to C4DCs, whereas DcuS without DctA is in the permanent ON state. In DctA, the C-terminal helix 8b (H8b) serves as the site for interaction with DcuS. Here the interaction site in DcuS and the related structural and functional adaptation in DcuS were determined. The Linker connecting transmembrane helix 2 (TM2) and the cytosolic PASC (Per-ARNT-SIM) domain of DcuS, was identified as the major site for interaction with DctA-H8b by in vivo interaction studies. The Linker is known to convert the piston-type…
Major histocompatibility complex class II binding site for streptococcal pyrogenic (erythrogenic) toxin A.
1994
Streptococcal pyrogenic exotoxin A (SPEA) is an important pathogenicity factor of group A streptococci. It is a member of the family of „superantigens” produced by Staphylococcus aureus and Streptococcus pyogenes and its T lymphocyte stimulating activity is involved into the pathogenesis of certain diseases caused by pyogenic streptococci. In this study we have produced and characterized recombinant SPEA molecules in Escherichia coli. These molecules are indistinguishable from natural SPEA in both T cell stimulatory and HLA class II binding activities. Human class II molecules are more efficient than mouse class II molecules in presenting SPEA to T cells. In binding tests to major histocomp…
Characteristics of Escherichia coli strains belonging to enteropathogenic E. coli serogroups isolated in Italy from children with diarrhea.
1996
Fifty-five Escherichia coli strains belonging to enteropathogenic E. coli (EPEC) serogroups were examined for phenotypic and genetic factors associated with virulence. The strains were isolated in Italy from children with diarrhea and identified as EPEC by clinical laboratories using commercially available antisera. O:H serotyping showed that 35 strains (27 of O26, O111, and O128 serogroups) belonged to 11 serotypes considered to be classical EPEC O:H serotypes. The other 20 isolates were classified as 15 nonclassical EPEC O:H serotypes. All the potential EPEC virulence factors associated with bacterial adhesion (localized adherence, fluorescentactin staining test positivity, presence of th…