Search PubMed⌕ Search

Biomedical subjects

H Chart

Publications and source records attributed to H Chart.

At least 73 records · Page 4Linked to original sources
PubMed1993

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↗
PubMed1993

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↗
PubMed1993

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↗
PubMed1993

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↗
PubMed1993

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↗
PubMed1993

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↗
PubMed1993

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↗
PubMed1993

Patients with haemolytic uraemic syndrome caused by Escherichia coli O157: absence of antibodies to Vero cytotoxin 1 (VT1) or VT2.

Serum samples from 30 patients with haemolytic uraemic syndrome (HUS), caused by Escherichia coli O157, and 30 apparently healthy volunteers, were used to examine the immune response of patients to Vero cytotoxins (VT) 1 and VT2. Patients' sera could not be differentiated from control sera using ELISA; and using immunoblotting, none of the sera had antibodies reactive with either the A or B subunits of VT1 or VT2. Examination of sera for antibodies to VT1 and VT2 seems to be of little value in the serodiagnosis of HUS caused by Vero cytotoxin-producing E coli O157.

Antibodies, Bacterial↗
PubMed1993

Structure and antigenic properties of Citrobacter freundii lipopolysaccharides.

Citrobacter freundii strain E69366 was detected in a colony immunoassay with a rabbit antiserum prepared to a strain of Escherichia coli belonging to serogroup O157. Lipopolysaccharide (LPS) was shown to contain the epitope(s) involved in antibody binding. LPS prepared from strain E69366, with hot phenol contained core-LPS that migrated to the water-phase and long-chain LPS that separated into the phenol-phase. A total of 36 strains of Cit. freundii were analysed for their LPS profiles by SDS-PAGE. Sixteen could be allocated into five groups (A(3), B(7), C(2), D(2) and E(2)) based on similarities in LPS profile. The remaining strains either expressed unique SDS-PAGE profiles (18) or did not express long-chain LPS (2). All strains with a profile 'A' reacted with the antiserum prepared to E. coli O157, whereas those with other profiles did not. The two strains of Cit. freundii expressing LPS profiles designated 'E' reacted with an antiserum prepared in rabbits to E. coli O45.

Adult↗
PubMed1992

Vero cytotoxin-producing Escherichia coli O 157 in the United Kingdom.

A total of 226 cultures of Vero cytotoxin-producing Escherichia coli O 157 isolated from humans was received by the PHLS Laboratory of Enteric Pathogens during the six month period January to June 1992. A record monthly total of 122 isolates was received in June. Ten phage types (PT) were identified during this period; PT 2 (45%) and PT 49 (21%) predominated. In addition, 27 human sera with antibodies to E. coli O 157 lipopolysaccharide (LPS) were examined from other cases during this period, making a total of 253 cases of infection associated with E. coli O 157.

Bacterial Toxins↗
PubMed1992

Airborne infection of laying hens with Salmonella enteritidis phage type 4.

Hens were exposed to small-particle aerosols containing different concentrations of Salmonella enteritidis phage type 4. They developed a systemic infection and some birds were still excreting the organism in the faeces when killed 28 days after infection. S enteritidis was present for a similar period in a wide range of alimentary tract issues and in the ovary and oviduct.

Aerosols↗
PubMed1992

Serological diagnosis of infection by Shigella dysenteriae-1 in patients with bacillary dysentery.

A total of 192 samples of serum from 113 Sri Lankan patients with clinical dysentery was examined for antibodies of the IgM class to the lipopolysaccharides (LPSs) of Shigella dysenteriae-1 and Escherichia coli O157:H7. By means of ELISA and immunoblotting, 59 patients were found to have serum antibodies to the LPS of S. dysenteriae-1 only. Four samples from one patient were found to contain serum antibodies to the LPSs of both S. dysenteriae-1 and E. coli O157:H7. Antibodies to the LPS of S. dysenteriae-1 were also detected in 16 samples from 25 children, from Sri Lanka, with no previous history of dysentery; one of these children also had antibodies to the LPS of E. coli O157:H7. Analysis of 16 samples from apparently healthy children in the U.K. showed that only one serum contained antibodies to the LPS of S. dysenteriae-1. This patient had a history of recent travel to Pakistan. The isolation of S. dysenteriae-1 remains the preferred test for the diagnosis of bacillary dysentery. The use of serology as a means of providing evidence of infection with S. dysenteriae-1, however may prove to be a useful adjunct to cultural techniques but needs to be validated in an area where this organism is endemic.

Child, Preschool↗
PubMed1992

Improved detection of infection by Escherichia coli O157 in patients with haemolytic uraemic syndrome by means of IgA antibodies to lipopolysaccharide.

Samples of serum from 125 patients with haemolytic uraemic syndrome, were screened for antibodies of the IgA and IgM classes to the lipopolysaccharide (LPS) of Escherichia coli O157:H7. By means of the techniques of ELISA and immunoblotting, 48 samples were shown to contain antibodies of the IgM class to E. coli O157 LPS, while 42 samples contained IgA antibodies to this O-antigen. Thirteen patients produced IgM but not IgA antibodies to the LPS of E. coli O157:H7. Of 42 patients with IgA antibodies to the E. coli O157 LPS, seven did not produce antibodies of the IgM class. From this study, screening patients' serum for antibodies to E. coli O157 LPS of the IgA class, in addition to those of the IgM class, a total of 55 patients were shown to be seropositive. This constituted an increase is in the sensitivity of obtaining evidence of infection by this organism by 12%.

Antibodies, Bacterial↗
PubMed1992

The serological relationship between Escherichia coli O157 and Yersinia enterocolitica O9 using sera from patients with brucellosis.

Sera from ten patients with positive brucella serology were used to investigate antibody cross-reactions between the O-antigens of Escherichia coli O157 and Yersinia enterocolitica O9. SDS-PAGE profiles of lipopolysaccharide (LPS), purified from strains of E. coli O157 and Y. enterocolitica O9, were reacted with sera by immunoblotting. All ten sera contained antibodies which bound to the LPS of E. coli O157, and five of these sera also contained antibodies which bound to the LPS of Y. enterocolitica O9. Absorption studies using these five cross-reacting sera indicated the existence of at least three epitopes exposed on the O-antigens of E. coli O157 and Y. enterocolitica O9. One antigen binding site appeared to be exposed on the LPS of both organisms, while one epitope was exposed on the LPS of E. coli O157 only, and another on the LPS of Y. enterocolitica O9 only.

Absorption↗
PubMed1992

Serological responses of chickens experimentally infected with Salmonella enteritidis PT4 by different routes.

Commercially reared chickens were challenged with Salmonella enteritidis phage-type (PT) 4 by aerosol, or via the conjunctiva. Inhalation of 2.9 x 10(2) or 4.2 x 10(3) S. enteritidis resulted in the production of IgG antibodies to the lipopolysaccharide (LPS) of S. enteritidis PT4. When the aerosol inoculum was increased to 2.4 x 10(5) bacteria per bird the antibody produced were predominantly of the IgM-class. Chickens challenged with 10(3) S. enteritidis PT4 via the conjunctiva mounted only a poor immune response. Increasing the challenge dose to 10(8) S. enteritidis resulted in the production of high-titre serum antibodies of both the IgG and IgM classes. Results from this study suggest that aerosols containing small numbers of S. enteritidis PT4 might be responsible for intraflock infection of poultry.

Animals↗
PubMed1991

Antibodies to lipopolysaccharide and outer membrane proteins of Salmonella enteritidis PT4 are not involved in protection from experimental infection.

BALB/c and Schofield mice were inoculated with formalin-killed bacteria prepared from strains of Salmonella enteritidis belonging to phage type (PT) 4 and carrying a 38 MDa plasmid and expressing long-chain lipopolysaccharide, or strains without a 38 MDa plasmid or lacking the ability to express lipopolysaccharide. Vaccinated mice were challenged with viable bacteria belonging to a virulent strain of S. enteritidis (PT4). Mice surviving this viable challenge were examined for a humoral antibody response to membrane antigens of S. enteritidis (PT4) that might relate to the possession of a given virulence property. BALB/c mice immunized with any of the test antigens were found to be immune to S. enteritidis (PT4), and this immunity was protective. Serum antibodies, of the IgG class, were detected to OmpA and a minor outer membrane protein (OMP) of 31 kDa. Schofield mice also raised IgG antibodies to these outer membrane proteins; however, non-immunized mice of this strain were resistant to infection. The virulence of S. enteritidis (PT4) was also tested using mice belonging to strains B10D2 (new), Biozzi (high), Biozzi (low), C3HeJ, B10ITYR and C57/L.

Animals↗