Analysis of bacterial outer membrane proteins.
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Bacterial Outer Membrane Proteins↗
Biomedical subjects
H Chart
Publications and source records attributed to H Chart.
Expression of outer membrane proteins by Salmonella enteritidis relating to pH.
The pH of the environment influenced the expression of outer membrane proteins by S. enteritidis PT4 growing in broth. Growth in broth at pH 5 to 7 resulted in variation in expression of outer membrane proteins of 18 to 22 kDa. Bacteria became acid-fixed and non-viable following prolonged incubation in broth with a pH below 5, and expression of flagella was repressed.
Animals↗
Antigenic cross-reactions between fimbriae expressed by Salmonella enteritidis, S. dublin and an 18 kDa outer membrane associated protein expressed by Escherichia coli O126:H27.
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Antigens, Bacterial↗
Subdivision of Salmonella enteritidis PT 4 by pulsed-field gel electrophoresis: potential for epidemiological surveillance.
Using pulsed-field gel electrophoresis (PFGE), nine profile types were identified in XbaI digests of a panel of strains of Salmonella enteritidis phage type 4 (PT 4) isolated in England and Wales between 1967 and 1992. When applied to 39 isolates from humans, chickens, poultry products and feed, strains belonging to pulsed-field profile (PFP) 1 predominated. DNA-DNA hybridization studies demonstrated that a band of approximately 57 kb was associated with the presence of the 38 MDa S. enteritidis 'serovar-specific' plasmid. It is concluded that PFGE provides a method for discriminating strains of S. enteritidis PT 4 suitable for epidemiological investigations.
Animals↗
Isolation of Vero cytotoxin-producing Escherichia coli serotypes O9ab:H- and O101:H-carrying VT2 variant gene sequences from a patient with haemolytic uraemic syndrome.
Vero cytotoxin-producing Escherichia coli (VTEC) were isolated from the faecal specimen of a patient with haemolytic uraemic syndrome. The isolates belonged to two rare VTEC serotypes, O9ab:H- and O101:H-. Polymerase chain reaction gene amplification products were detected with primers specific for the VT2e gene, a variant of VT2. The toxin from both isolates was cytotoxic to Vero cells but not to HeLa cells. An 18 kb EcoRI restriction enzyme fragment of genomic DNA from both strains hybridised with a VT2 polynucleotide DNA probe.
Aged↗
Use of plasmid profile typing for surveillance of Salmonella enteritidis phage type 4 from humans, poultry and eggs.
Plasmids were found in 1022 of 1089 (94%) of drug-sensitive strains of Salmonella enteritidis phage type 4 from humans (sporadic and outbreak cases), poultry (chickens) and eggs in England and Wales in the 5-year period 1988-92 and 25 plasmid profile patterns were identified. Strains characterized by a single plasmid of 38 MDa predominated (= plasmid profile type SE 38), comprising over 90% of isolates from humans, 70% from poultry and 92% from eggs. Eleven profile types were identified in strains from humans, 21 in strains from poultry and 3 in strains from eggs. Eight of the 11 patterns identified in human isolates were found in strains from poultry and 2 in strains from eggs. In contrast 15 patterns seen in poultry were not found in strains from humans. Four percent of strains from humans and 13% from poultry did not carry the 38 MDa plasmid but all strains from eggs were found to carry this plasmid. The second most common profile type in strains isolated between 1981 and 1988 was not identified in strains isolated from 1988-92. It is concluded that plasmid profile typing is a useful method for rapid differentiation within phage type 4 of S. enteritidis but that methods which can discriminate within the predominant profile type, SE 38, are now required.
Animals↗
Prospective study of verocytotoxin-producing, enteroaggregative and diffusely adherent Escherichia coli in different diarrhoeal states.
One hundred and eighty-one stool specimens from patients with various types of diarrhoea (135 patients) or from non-diarrhoeal controls (23 acute medical patients, 23 inflammatory bowel disease in remission) were investigated using a colony-blot DNA hybridization assay for the presence of Verocytotoxin-producing (VTEC), enteroaggregative (EAggEC) and diffusely adherent (DAEC) Escherichia coli. Twelve patients had probe-positive EAggEC in the stool and 8 of these had diarrhoea, 6 following recent travel. Eight patients had DAEC, 7 of whom had travellers' diarrhoea. Six of 10 (60%) travellers with gastroenteritis, but without a recognized enteric pathogen, were positive for EAggEC (4) or DAEC (2). Five of 10 (50%) travellers with gastroenteritis related to a recognized enteric pathogen also had DAEC identified in their stool. Of the 23 acute medical control patients 11 had been abroad, 4 of these were immigrants and had EAggEC. VTEC were not found and, with one exception, immunoassays for antibodies to E. coli O 157 and O 2 lipopolysaccharides were negative.
Adult↗
A rapid immunoblotting procedure for detecting serum antibodies to the lipopolysaccharide of Escherichia coli O157.
An immunoblotting method, which can be completed in one day, is described for the detection of serum antibodies to Escherichia coli O157 lipopolysaccharide.
Antibodies, Bacterial↗
Antibody cross-reactions with lipopolysaccharide from E. coli O157 after cholera vaccination.
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Antibodies, Bacterial↗
Expression of a new porin 'OmpE' by strains of Salmonella enteritidis.
Strains of Salmonella enteritidis expressed a novel porin with a subunit size of 35.5 kDa as shown by SDS-PAGE. This protein was expressed as a major outer membrane protein (MOMP) when grown on nutrient agar, McConkey agar or blood agar, or in Tris-succinate medium; but was only produced in trace amounts when strains were grown in nutrient broth. This OMP was produced by all strains of S. enteritidis examined, regardless of phage type, and expression was not related to the possession of a 38-MDa mouse-virulence plasmid or the ability of strains to make long-chain lipopolysaccharide. This new porin has been tentatively called OmpE.
Bacterial Outer Membrane Proteins↗
Serological detection of verocytotoxin-producing Escherichia coli in patients with haemolytic uraemic syndrome in western Europe.
Sera from 45 patients from The Netherlands, Germany and Belgium who had a clinical diagnosis of haemolytic uraemic syndrome (HUS) were screened for antibodies to the lipopolysaccharide (LPS) of Escherichia coli producing Verocytotoxin (VTEC). Sera from 43 family contacts and 34 control patients were also examined. Using the techniques of EIA and immunoblotting, antibodies to the LPS of Escherichia coli O157 were found in 28 patients, and to the LPS of serogroups O115 and O145 in one patient and one family member respectively. The results of our study suggest that VTEC, and in particular Escherichia coli O157, might be a significant cause of HUS in Western Europe.
Antibodies, Bacterial↗
Heterogeneity in expression of lipopolysaccharides by strains of Escherichia coli O157.
A total of 47 strains of Escherichia coli belonging to serogroup O157 were examined for the expression of long-chain lipopolysaccharide (LPS) by means of SDS-PAGE and silver staining. Strains belonged to 10 different flagellar (H) types or did not express flagella. Nine strains carried genes encoding Vero cytotoxin (VT). Strains of E. coli O157 expressed one of three LPS SDS-PAGE profiles designated A, B and C. Strains expressing profile A belonged to H-types 6 and 19, while those expressing LPS profile B belonged to H-types 2, 16, 20, 39, 42 and 45. Strains of E. coli expressing profile C belonged to H-types 7 and 8; strains producing VT expressed LPS profile C only, although not all strains with H-types 7 and 8 carried genes for VT. Regardless of H-type or the LPS profile expressed, serum antibodies produced by patients infected with strains of E. coli belonging to serogroup O157 would be detected by serological tests.
Antigens, Bacterial↗
Iron restriction and the growth of Salmonella enteritidis.
Strains of Salmonella enteritidis were examined for their ability to remove ferric-ions from the iron chelating agents ovotransferrin, Desferal and EDDA. Growth of S. enteritidis phage type (PT) 4 (SE4) in trypticase soy broth containing ovotransferrin resulted in the expression of iron regulated outer membrane proteins (OMPs) of 74, 78 and 81 kDa, and unexpectedly the repression of expression of OMP C. The 38 MDa 'mouse virulence' plasmid was not required for the expression of the iron-regulated OMPs (IROMPs). SE4 was able to obtain iron bound to the iron chelator Desferal and EDDA without expressing a high-affinity iron uptake system. Strains of S. enteritidis belonging to PTs 7, 8, 13a, 23, 24 and 30 were also able to remove ferric ions from Desferal and EDDA without expressing a high-affinity iron uptake system. We conclude that strains of SE4 possess a high-affinity iron sequestering mechanism that can readily remove iron from ovotransferrin. It is likely that iron limitation, and not iron restriction, is responsible for the bacteriostatic properties of fresh egg whites.
Bacterial Outer Membrane Proteins↗
Vero cytotoxin-producing Escherichia coli, particularly serogroup O 157, associated with human infections in the United Kingdom: 1989-91.
This survey reports the results of investigations performed by the Laboratory of Enteric Pathogens (LEP), to identify evidence of human infection with Vero cytotoxin-producing Escherichia coli (VTEC) in the UK during the period 1989-91. Bacterial isolates, faecal specimens and serum samples were received from patients suffering from diarrhoea, bloody diarrhoea and haemolytic uraemic syndrome. Using serotyping, Vero cytotoxin gene probing and an ELISA for serum antibodies to E. coli O 157, evidence of infection was detected in 232, 428 and 615 individuals in 1989, 1990 and 1991 respectively. Of these individuals, 15% were reported as having HUS. Vero cytotoxin-producing E. coli O 157 was the most frequently encountered serogroup, with isolations from a total of 1092 individuals over the 3-year period. The incidence of VTEC infection increased from 0.41/100,000 in 1989 to 1.07/100,000 in 1991. The area with the highest rate of infection in each year was Scotland, increasing from 1.37/100,000 in 1989 to 3.97/100,000 in 1991.
Adolescent↗
Interrelationships between strains of Salmonella enteritidis.
In contrast to S. typhimurium [19], S. enteritidis is a serotype which has its primary food-animal reservoir in poultry. To date, phage typing has been of paramount importance in studying the epidemiology of this serotype and in particular, has demonstrated the involvement of both poultry meat and whole shell eggs in the transmission of S. enteritidis PT4 to humans. The findings discussed above describe various aspects of the serotype, particularly in relation to the involvement of both LPS and plasmids in its virulence and phage type identity (Fig. 2). These findings have led to an increased understanding of the biology of this serotype, which is of major importance in human food-poisoning in England and Wales at the present time.
Bacterial Typing Techniques↗
Outer membrane characteristics of Salmonella enteritidis phage type 4 growing in chickens.
Strains of Salmonella enteritidis belonging to phage type 4 (SE4) were grown in the peritoneal cavities of chickens, and without subculture on laboratory media examined for inducible in vivo phenotypic characteristics. These bacteria expressed three major outer membrane proteins (OMPs) of 33, 35 and 36 kilodaltons (kDa), and iron regulated OMPs of 74, 78 and 81 kDa. Bacteria growing in vivo did not express flagella, or fimbriae with a subunit molecular mass of 14 kDa (14 kDa fimbriae). Two OMPs of 55 and 23 kDa, expressed during culture in nutrient broth, were repressed during growth in chickens. Possession of a 38 MDa 'mouse virulence' plasmid did not influence the expression of OMPs, flagella or fimbriae. It was concluded that strains of SE4 growing in chicken tissues, use an enterobactin mediated iron uptake system to obtain ferric ions, do not express flagella or 14 kDa fimbriae and appear not to express novel OMPs involved in survival in vivo.
Animals↗
Interrelationships between strains of Salmonella enteritidis belonging to phage types 4, 7, 7a, 8, 13, 13a, 23, 24 and 30.
Salmonella enteritidis strain P278849 expressed long-chain lipopolysaccharide (LPS, termed 'smooth'), carried plasmids of 38, 34 (pDEP 44, incompatibility group N, R-type AS), 2.0 and 1 MDa, and belonged to phage type (PT) 23. Introduction of pDEP 44 into a smooth strain of Salm. enteritidis PT 4 produced a smooth strain of Salm. enteritidis of PT 24. Transfer of this plasmid into a strain of PT 8 also resulted in formation of a smooth strain of Salm. enteritidis of PT 24. Moving pDEP 44 into strains of Salm. enteritidis of PTs 7 or 7a which did not express LPS (termed 'rough') resulted in rough strains of PT 23. In contrast, transfer of this plasmid into a smooth strain of Salm. enteritidis PT 7a resulted in a smooth strain of PT 23. Introduction of pDEP 44 into strains of Salm. enteritidis of PT 13 or PT 13a did not change the phage type, whereas transferring the plasmid into strains of PT 30 caused strains to become resistant to lysis by the typing phages and therefore untypable. The possibility of strains of Salm. enteritidis of PT 8 being the progenitors of strains of Salm. enteritidis of PT 24 must now be considered when investigating the epidemiology of Salm. enteritidis of PT 24 infections in areas where Salm. enteritidis PT 8 is common.
Animals↗
Concentrations of interleukin 6 and tumour necrosis factor in serum and stools of children with Shigella dysenteriae 1 infection.
Serum interleukin 6 (IL-6) and tumour necrosis factor (TNF) were measured in children with dysentery during an epidemic caused by Shigella dysenteriae 1. IL-6 and TNF were also measured in fresh stool filtrates from children with acute gastroenteritis. The median serum IL-6 concentration was raised significantly in the children with complications (haemolytic uraemic syndrome, leukemoid reaction, thrombocytopenia, thrombocytosis, and severe colitis lasting more than one week) during the first week (n = 18, 9-7728 pg/ml; median 107) and in the second week (n = 13, 5-312 pg/ml; median 77), compared with convalescent sera (n = 10, < 3-85 pg/ml; median 39; p < 0.02 and < 0.05 respectively). The median IL-6 concentration during the first week was significantly higher in the group with complicated disease than in those with no complications (n = 8, < 3-37 pg/ml; median 5; p < 0.001). Although serum TNF concentrations were significantly raised in the complicated group during the first and second weeks of the illness and in the uncomplicated group compared with convalescence, there was no significant difference in the TNF concentrations between the complicated and uncomplicated groups. IL-6 was detectable in stool filtrates from eight of 13 children with S dysenteriae 1 infection and four of eight children with S flexneri infection. It was not detectable in Cryptosporidia, rotavirus, or adenovirus infections, those with pathogen-negative acute diarrhoea or controls. Seven of 13 children with S dysenteriae 1 and three of nine children with S flexneri infections had TNF detectable in stools. None of the children with Salmonella, Cryptosporidia, rotavirus of children with pathogen-negative diarrhoea and controls had detectable TNF in stool filtrates. It is postulated that the local and generalised vasculitis observed in shigellosis may be related to a direct effect of Shiga toxin on endothelial cells or caused by cytokine production stimulated by endotoxin, or both.
Child↗