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Biomedical subjects

B Rowe

Publications and source records attributed to B Rowe.

At least 235 records · Page 13Linked to original sources
PubMed1989

Properties of adherence factor plasmids of enteropathogenic Escherichia coli and the effect of host strain on expression of adherence to HEp-2 cells.

EPEC adherence factor (EAF) plasmids from three strains of enteropathogenic Escherichia coli (EPEC) - E2347/69 (O127:H6), E20517 (O111:H2) and E24582 (O142:H6) - were examined. The EAF plasmids were all marked with ampicillin resistance by transposition of Tn801 to give pDEP1, pDEP2 and pDEP11, respectively. All three plasmids showed incompatibility with an FIme and an FIV plasmid and had some similarity in restriction enzyme digest patterns. Plasmid pDEP1 differed from pDEP2 and pDEP11 in being autotransferring and fertility-inhibition positive. An EAF probe consisting of a 1 kb BamHI-SalI restriction endonuclease fragment of the prototype EAF-associated plasmid pMAR2 hybridized to similar-sized SalI-BamHI fragments of pDEP1 and pDEP11 but to a different-sized fragment of plasmid pDEP2. Loss of the EAF plasmids from EPEC strains resulted in a marked reduction in the ability of these strains to adhere to HEp-2 cells. The EAF-plasmid-negative variants did not express a 94 kDa outer-membrane protein (OMP). When these EAF plasmids were reintroduced into EAF-plasmid-negative EPEC strains a high level of adherence equivalent to that of the parent EPEC strains was restored and a 94 kDa OMP was usually expressed. However, when EAF plasmids were transferred into E. coli K12 or non-EPEC E. coli the host strains either did not adhere or adhered poorly to the HEp-2 cells. These transconjugants did not express a 94 kDa OMP.

Adhesins, Escherichia coli↗
PubMed1989

Characterization of a putative colonization factor (PCFO166) of enterotoxigenic Escherichia coli of serogroup O166.

Enterotoxigenic Escherichia coli (ETEC) of serogroup O166 gave mannose-resistant haemagglutination (MRHA) with bovine and human erythrocytes. The strains did not react with antisera prepared against the known colonization factors CFA/I, CFA/II, CFA/III, CFA/IV and PCFO159:H4. Strain E7476 of serotype O166:H27, which produced heat-stable enterotoxin (ST), was examined initially. It produced fimbriae about 7 nm in diameter. On SDS-PAGE two possible fimbrial polypeptides of molecular mass 15.5 and 17.0 kDa were seen. When variants of strain E7476 were isolated, loss of ST and MRHA together was associated with loss of a 98 MDa plasmid, while loss of ST alone correlated with plasmid deletion. An absorbed anti-strain E7476 antiserum reacted specifically with the 15.5 and 17.0 kDa polypeptides in Western immunoblotting and bound to the intact fimbriae by immuno-electron microscopy. When this antiserum was used in an ELISA to examine other strains of serogroup O166, a positive reaction was obtained with all the ST- and MRHA-positive strains. One strain of serotype O71:H27 and two strains of serotype O98:H- also reacted with the absorbed anti-strain E7476 antiserum. The antiserum did not react with ETEC carrying known colonization factors. E. coli K12 and a number of E. coli of different serotypes carrying a plasmid coding for ST transferred from strain E7476, all gave MRHA and reacted with the absorbed anti-strain E7476 antiserum. The term putative colonization factor O166 (PCFO166) is proposed to describe the adhesive factor(s) on ETEC of serogroup O166 because of the similarity of properties with those of known colonization factors.

Antibodies, Bacterial↗
PubMed1989

Comparison of Vero-cytotoxin-encoding phages from Escherichia coli of human and bovine origin.

Phages encoding production of Vero cytotoxins VT1 or VT2 were isolated from strains of Escherichia coli of human and bovine origin. Two human strains of serotype O157: H7 produced both VT1 and VT2 and each carried two separate phages encoding either VT1 or VT2. The phages were morphologically similar to each other and to a VT2 phage previously isolated from a strain of serotype O157: H-; all had regular hexagonal heads and short tails. The phages had similar genome sizes and DNA hybridization and restriction enzyme digestion showed that the DNAs were very closely related. This contrasts with another report that one of the strains tested (933) released two clearly distinguishable phages separately encoding VT1 and VT2. The O157 phages differed from a VT1 phage isolated from a bovine E. coli strain belonging to serotype O26: H11 and from the reference VT1 phage isolated previously from a human strain, H19, of serotype O26: H11. The two O26 phages were morphologically similar with elongated heads and long tails. They had similar genome sizes and DNA hybridization indicated a high level of homology between them. Hybridization of an O157 phage DNA probe to DNA of the O26 phages, and vice versa, showed there was some cross-hybridization between the two types of phage. A phage from a bovine strain of serotype O29: H34 had a regular hexagonal head and short tail resembling those of the O157 phages. The DNA was distinguishable from that of all the other phages tested in restriction digest patterns but hybridized significantly to that of an O157 phage. Hybridization of the phage genomes with VT1 and VT2 gene probes showed that sequences encoding these toxins were highly conserved in the different phages from strains belonging to the three serogroups.

Animals↗
PubMed1989

Adhesion and ultrastructural properties of human enterotoxigenic Escherichia coli producing colonization factor antigens III and IV.

Human enterotoxigenic Escherichia coli (ETEC) producing colonization factor antigen III (CFA/III) and coli surface antigens 4, 5, and 6 (CS4, CS5, and CS6) of CFA/IV were examined ultrastructurally and for ability to adhere to human small intestinal enterocytes and to cultured human intestinal mucosa. Strains of serotypes O25:H-, O25:H42, and O167:H5 producing CFA/III plus CS6, CS4 plus CS6, and CS5 plus CS6, respectively, showed good adhesion to human enterocytes (1.8 to 4.2 bacteria per brush border) and cultured human intestinal mucosa, whereas variants lacking these antigens or producing only CS6 were nonadherent (0 to 0.03 bacterium per brush border). By electron microscopy, CFA/III, CS4, and CS5 appeared as morphologically distinct rodlike fimbriae: CFA/III was 7 to 8 nm in diameter, CS4 was 6 to 7 nm in diameter, and CS5 was 5 to 6 nm in diameter. CS5 was unusual in that it appeared to be composed of two fine fibrils arranged in a double-helical structure. CS6 was difficult to characterize morphologically but possibly has a very fine fibrillar structure. By specific fimbrial staining and immunoelectron microscopy. CS4 and CS5 were shown to promote mucosal adhesion of ETEC; a similar adhesion role for the CS6 antigen could not be confirmed. ETEC strains of serotypes O27:H7, O27:H20, O148:H28, and O159:H20 which produced CS6 showed good adhesion to human enterocytes (1.6 to 3.0 bacteria per brush border), whereas variants which lacked CS6 were nonadherent (0 to 0.01 bacterium per brush border). These strains, however, also produced fimbrial or fibrillar surface antigens, in addition to CS6, which probably represent additional coli surface antigens responsible for the observed adhesive properties of these ETEC serotypes.

Antigens, Bacterial↗
PubMed1989

Serum antibodies to Escherichia coli serotype O157:H7 in patients with hemolytic uremic syndrome.

Sera from 13 patients with hemolytic uremic syndrome (HUS) and 8 healthy control subjects were examined for antibodies specific for bacterial antigens of Eschericia coli serotype O157:H7. Bacterial components, including outer membrane proteins (OMPs), lipopolysaccharide (LPS), and flagella, were reacted with sera by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting and by enzyme-linked immunosorbent assay. All 13 serum samples from HUS patients contained high-titered antibodies of the immunoglobulin M class against O157 LPS and some OMPs. These same sera reacted weakly with some of the major OMPs, but not the LPS, of non-O157 strains of E. coli. Sera from patients did not contain antibodies to non-O157 LPS or H7 flagella. The possibility of using E. coli serotype O157 LPS in an enzyme-linked immunosorbent assay for the routine diagnostic testing of sera from HUS patients for evidence of O157:H7 infection is discussed.

Antibodies, Bacterial↗
PubMed1989

Evaluation of a reversed passive latex agglutination test for detection of Escherichia coli heat-labile toxin in culture supernatants.

One hundred strains of Escherichia coli were tested for the production of the heat-labile enterotoxin by the Y1 adrenal cell test and a commercially available reversed passive latex agglutination test. The strains were grown in Casamino Acids-yeast extract broth, and filtered culture supernatants were tested for the presence of heat-labile enterotoxin. There was perfect correlation between the Y1 test and the reversed passive latex agglutination test, and the latter was simple to perform and completed within 48 h.

Bacterial Toxins↗
PubMed1989

Four new provisional serovars of Shigella.

Four bacterial strains are described that possess the biochemical characteristics of Shigella species but do not belong to any of the established Shigella serovars or to any previously described provisional serovar. One strain fermented mannitol, and it is proposed that this be the type strain for a new provisional serovar of Shigella boydii. The remaining strains did not ferment mannitol and belonged to three different serovars. These strains are proposed as type strains for three new provisional serovars of Shigella dysenteriae. All four strains were invasive in a HEp-2 cell tissue culture test, but only one was invasive in the guinea pig eye test and might therefore be expected to cause dysenterylike illness in humans. It is important that the designation of such strains remain provisional until other reference laboratories have had the opportunity to search for additional isolates and the possible pathogenicity of these strains for humans can be further assessed.

Agglutination Tests↗
PubMed1989

Identification of Escherichia coli that produces heat-stable enterotoxin STA by a commercially available enzyme-linked immunoassay and comparison of the assay with infant mouse and DNA probe tests.

By using the infant mouse test and a commercially available competitive enzyme-linked immunosorbent assay (ELISA), 100 strains of Escherichia coli carrying STA1 or STA2 genes were shown to produce the heat-stable enterotoxin STA. An additional 100 strains were negative in both tests. The ELISA was easy to perform, and results were available within 24 h. Testing strains with an enzyme-linked DNA probe kit that incorporated both STA1- and STA2-specific oligonucleotides showed that the 100 strains positive in the mouse test and ELISA also hybridized with the mixed probe. Two strains carrying STA1 genes but negative in the mouse test and ELISA also hybridized with the mixed probe.

Animals↗
PubMed1989

Antibodies to Escherichia coli O157 in patients with haemorrhagic colitis and haemolytic uraemic syndrome.

Twenty four sera from patients with haemolytic uraemic syndrome or haemorrhagic colitis and healthy controls were examined for antibodies to the lipopolysaccharide (LPS) of Escherichia coli O157. Faecal specimens from these patients were also examined for Vero cytotoxin producing E coli (VTEC) by DNA probes, and for faecal Vero cytotoxin. Eight patients with faecal E coli O157:H7 gave a strong antibody response to O157 LPS, shown by immunoblotting and an enzyme linked immunosorbent assay. Six symptomatic patients without evidence of faecal VTEC also gave a strong antibody response to O157 LPS. Sera from the remaining five patients and five healthy controls did not contain antibodies to E coli O157. The results suggest that the testing of sera from patients with haemorrhagic colitis or haemolytic uraemic syndrome by ELISA or immunoblot would prove valuable in addition to the established procedures for detecting VTEC, using DNA probes and testing for faecal Vero cytotoxin.

Antibodies, Bacterial↗
PubMed1989

An epidemic of Vibrio cholerae el tor Inaba resistant to several antibiotics with a conjugative group C plasmid coding for type II dihydrofolate reductase in Thailand.

Between June and October 1982, Vibrio cholerae el tor Inaba phage type Russian 13, resistant to ampicillin (Ap), chloramphenicol (Cm), colistin, neomycin (Nm), kanamycin (Km), gentamicin (Gm), trimethoprim sulfamethoxazole (TMP-SMZ), and tetracycline (Tc), was isolated from 31 children with diarrhea at a hospital in Samutsakorn, Thailand. Thirty of these children were less than 2 years of age and were admitted to a single pediatric ward. Seventeen of the cases, infected with V. cholerae (MARV) resistant to several antibiotics, were admitted to the hospital for non-gastrointestinal illnesses; these children developed diarrhea and positive cultures for MARV 1-greater than 10 days after admission. The majority of cases occurred in September, when the attack rate in the patient population in 1 pediatric ward was 11.5%. During this period, MARV with the same characteristics was isolated from water used for bathing in a reservoir on the pediatric ward where most of the cases occurred. MARV was not isolated from adults with diarrhea at the hospital. No further MARV infections occurred at the hospital after the water reservoir had been drained and disinfected. V. cholerae isolates from children and water contained a conjugative incompatibility group C plasmid of 100 megadaltons (mDa) encoding resistance to Ap, Cm, Nm, Km, Gm, TMP-SMZ, and Tc. This plasmid hybridized with a DNA probe for genes encoding Type II dihydrofolate reductase (DHFR). As far as we know, this is the first report of MARV with V. cholerae that contained genes coding for Type II DHFR.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗
PubMed1988

Salmonella enteritidis phage type 4 infection: association with hen's eggs.

Epidemiological and microbiological investigation of the four outbreaks of Salmonella enteritidis phage type (PT) 4 that occurred in Wales in 1988 implicated foods containing shell eggs from hens as the vehicle of infection. In a case-control study of sporadic cases there was a significant association between infection and egg consumption in the 3 days before illness. These findings provide data to support the warnings from the Departments of Health in the United Kingdom about risks of infection from eating raw or undercooked hens' eggs.

Adult↗
PubMed1988

Microalbuminuria in diabetic subjects with chronic peripheral neuropathy.

Fifty-five patients with chronic peripheral neuropathy, 31 with and 24 without retinopathy, had albumin excretion rates determined on 2-h supine urine collections on three occasions by a radioimmunoassay method. Four patients with retinopathy had albustix-positive proteinuria and were excluded from subsequent analysis. Microalbuminuria was found in 20 of the 27 patients with retinopathy compared with 10 of the 24 patients with neuropathy alone. The mean albumin excretion rate (AER) was higher in neuropathic patients with retinopathy than in those patients with neuropathy alone (41.2 +/- 40.3 vs 18.8 +/- 33.2 micrograms/min, P less than 0.01). Multivariate analysis of the data was performed and this revealed a correlation coefficient of R2 = 0.33 (P less than 0.01) for AER as the dependent variable with respect to the independent variables HbA1, systolic blood pressure and known duration of diabetes. There was, however, no significant contribution separately of these individual variables to the regression equation. Microalbuminuria was significantly associated with retinopathy although almost half of the patients with neuropathy alone had microalbuminuria. The association between microalbuminuria and neuropathy even in the absence of retinopathy provides support for a microvascular element in the pathogenesis of diabetic neuropathy.

Albuminuria↗
PubMed1988

Epidemic multiresistant Escherichia coli infection in West Lambeth Health District.

A year-long outbreak of multiresistant Escherichia coli K52 H1, predominantly serogroup O15, is reported from south east London. Most patients had urinary tract infections, some with septicaemia; but some cases of septicaemia were associated with pneumonia, meningitis, and endocarditis--unusual infections for E coli. 3 of these patients died. The organism was acquired in the community, and its source is still being investigated.

Adolescent↗
PubMed1988

The use of sorbitol-MacConkey agar in conjunction with a specific antiserum for the detection of Vero cytotoxin-producing strains of Escherichia coli O 157.

Using DNA probes specific for the genes encoding Vero cytotoxins 1 and 2 in hybridization experiments on faecal samples, Vero cytotoxin-producing Escherichia coli (VTEC) of serogroup O 157 were detected in 21 of 63 cases of haemorrhagic colitis, 9 of 31 cases of non-bloody diarrhoea and 14 of 68 cases of haemolytic uraemic syndrome. Compared with these results sorbitol-MacConkey agar in conjunction with a specific O 157 antiserum gave a sensitivity of 62% in haemorrhagic colitis, 56% in non-bloody diarrhoea and 57% in haemolytic uraemic syndrome. The specificity of this method was 100% in all three groups. This demonstrates that sorbitol-MacConkey agar is a useful screening method for the detection of VTEC of serogroup O 157 when used in conjunction with a specific homologous antiserum. However, this method does not detect VTEC belonging to other serogroups and such strains were found, particularly in cases of haemolytic uraemic syndrome.

Adolescent↗