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S Tabaqchali

Publications and source records attributed to S Tabaqchali.

At least 91 records · Page 5Linked to original sources
PubMed1987

Restriction endonuclease DNA analysis of Clostridium difficile.

HindIII restriction enzyme digests of genomic DNA from nine distinct strains of Clostridium difficile were undertaken, and the results were related to those of a previously established typing method based on [35S]methionine-labeled protein profiles. Each of the typed strains identified by its protein profile could also be distinguished by its unique DNA digestion pattern. Analysis of strains isolated from 10 patients during a hospital outbreak of antibiotic-associated colitis revealed identical DNA profiles, confirming a single strain as the source of cross-infection. Characterization of isolates from worldwide sources revealed similar digestion patterns within the same strain type. Restriction endonuclease DNA analysis provides a sensitive and useful technique for studying the epidemiology of C. difficile.

Clostridium↗
PubMed1987

Isolation of immunodominant antigens from sera of patients with systemic candidiasis and characterization of serological response to Candida albicans.

Candidal antigens were isolated by affinity chromatography from the sera of patients with disseminated Candida albicans infections. The immunodominant 47-kilodalton (kDa) antigen appeared to be a heat-stable breakdown product of several larger heat-labile components (84 to 92, 74 to 79, and 66 to 72 kDa). It was undetectable in normal sera and sera from four patients with systemic C. parapsilosis, C. tropicalis, and C. krusei infections. Serum samples from 92 patients with proven systemic C. albicans infections were examined by the immunoblot technique. Seventy-four patients had detectable antibody, and 92% of these produced antibody to the 47-kDa antigen. All survivors had major serological responses to this antigen, whereas patients who died had no, minor, or fading responses. Fifty-five of the patients were neutropenic following cytotoxic chemotherapy for malignancies, usually lymphoproliferative disorders (hematological patients). The remainder were surgical or medical patients (nonhematological). Hematological patients differed from nonhematological patients in the range of antigens that were commonly recognized by their immune systems, although antibodies to the 47- and 60-kDa antigens were frequently present in both groups. They also differed in that they produced mainly an immunoglobulin M (IgM) response, failing to seroconvent to IgG. This did not reduce survival rates, which were similar in both groups. It may be responsible, however, for the lower antigen titers that were observed in hematological patients when measured by reverse passive latex agglutination.

Antibodies, Fungal↗
PubMed1987

Association between production of toxins A and B and types of Clostridium difficile.

One hundred and seventy two strains of Clostridium difficile isolated from 62 patients with antibiotic associated diarrhoea or pseudomembranous colitis were analysed for the production of toxins A and B and typed using 35S-methionine labelling followed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). There was a correlation between production of toxins A and B and the type of C difficile. One hundred and forty four of 172 strains were either high or low producers of both toxins. Toxins were not detected in 28 of 172 strains. Types A and Y were consistently non-toxin producers; types B and E were high toxin producers. Type X, the epidemic strain, showed variable toxin production. Symptoms of 49 patients with haematological malignant pathology who were part of a documented outbreak of antibiotic associated diarrhoea, were analysed in relation to toxin production and type of the clinical strains isolated. In general, there was a correlation between symptoms of antibiotic associated diarrhoea, the type of C difficile, and its potential for producing toxins.

Anti-Bacterial Agents↗
PubMed1987

Automation in clinical microbiology: a new approach to identifying micro-organisms by automated pattern matching of proteins labelled with 35S-methionine.

A new rapid automated method for the identification and classification of microorganisms is described. It is based on the incorporation of 35S-methionine into cellular proteins and subsequent separation of the radiolabelled proteins by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein patterns produced were species specific and reproducible, permitting discrimination between the species. A large number of Gram negative and Gram positive aerobic and anaerobic organisms were successfully tested. Furthermore, there were sufficient differences within species between the protein profiles to permit subdivision of the species. New typing schemes for Clostridium difficile, coagulase negative staphylococci, and Staphylococcus aureus, including the methicillin resistant strains, could thus be introduced; this has provided the basis for useful epidemiological studies. To standardise and automate the procedure an automated electrophoresis system and a two dimensional scanner were developed to scan the dried gels directly. The scanner is operated by a computer which also stores and analyses the scan data. Specific histograms are produced for each bacterial species. Pattern recognition software is used to construct databases and to compare data obtained from different gels: in this way duplicate "unknowns" can be identified. Specific small areas showing differences between various histograms can also be isolated and expanded to maximise the differences, thus providing differentiation between closely related bacterial species and the identification of differences within the species to provide new typing schemes. This system should be widely applied in clinical microbiology laboratories in the near future.

Automation↗
PubMed1986

New method for typing Staphylococcus aureus resistant to methicillin based on sulphur-35 methionine labelled proteins: its application in an outbreak.

Sodium dodecyl sulphate polyacrylamide gel electrophoresis of sulphur-35 methionine labelled cellular proteins of Staphylococcus aureus resistant to methicillin was used as a typing method during an outbreak on a cardiothoracic ward. This showed that the outbreak strain was indistinguishable from the epidemic strain of methicillin resistant S aureus prevalent in London. In contrast, 44 epidemiologically separate strains of S aureus gave individually distinct radiolabelled protein profiles. This method permitted rapid confirmation that an epidemic strain was responsible and indicated the need for urgent control measures.

Bacterial Proteins↗
PubMed1986

Synthesis of histamine by Haemophilus influenzae.

Recent findings suggest that bacteria might contribute to histamine concentrations in the sputum of patients with infective lung disease. Ten isolates of Haemophilus influenzae from patients with acute exacerbation of chronic bronchitis and emphysema, together with two reference strains, were incubated at 37 degrees C for 72 hours. Serial estimations of histamine concentrations by high pressure liquid chromatography showed significant increases at 24 and 48 hours; no increases were evident in the control samples. These findings suggest that H influenzae might contribute to inflammation and limited airflow in infective lung disease by producing histamine.

Bronchitis↗
PubMed1986

Anaerobic bacterial meningitis.

We report a case of anaerobic bacterial meningitis in which a rapid diagnosis was achieved by direct gas-liquid chromatography of cerebrospinal fluid.

Aged↗
PubMed1986

Analysis of the antibody response developing in an infant with Candida albicans meningitis.

A case of meningitis due to Candida albicans in a neonate is described. This is the first report of an immunoblot analysis of both serial samples of serum and cerebrospinal fluid in relation to C. albicans antigens. The western blot technique demonstrated that the mother had IgM antibody against five candidal antigens, including one of molecular weight 47 kDaltons, but only a small amount of IgG antibody against two antigens of molecular weight 104 kDaltons and 60 kDaltons respectively. The baby produced IgM antibody and then IgG antibody against an antigen of 47 kDaltons molecular weight, and this was associated with recovery.

Antibodies, Fungal↗
PubMed1986

Relationship of toxin production to species in the genus Aeromonas.

Ninety-five strains of Aeromonas were divided into three species--A. sobria, A. hydrophila and A. caviae--on the basis of results in 13 biochemical tests. The minimum number of tests necessary to distinguish these species was determined. Culture filtrate of the strains were tested for cytotoxin and cytotonin, haemolysin and protease. One filtrate with high-titre cytotoxin, haemolysin and protease activities was subjected to gel filtration on Sephadex G75 and isoelectric focussing. Of the five cell lines tested, Vero cells were most sensitive to the cytotoxin; no reproducible cytotonic effects were observed. The haemolysin effect appeared to be equivalent to cytotoxin. At least two distinct protease activities were found that might be responsible for the cytotonic effects described. Cytotoxin production was species related; it was present in A. sobria and A. hydrophila but not in A. caviae.

Aeromonas↗
PubMed1986

Toxin production by Aeromonas spp. from different sources.

One hundred and eleven isolates of Aeromonas from water and from human sources were identified to species level and tested for the production of cytotoxin. These results were correlated with the source of each isolate and, for those from human faeces, with the clinical history of diarrhoea. A. caviae predominated in water, comprising 16 of 32 isolates; only one isolate from water was A. sobria. In human faecal samples 21 of 76 isolates were A. sobria; this was a significant difference. Cytotoxin producing strains were significantly more common in patients with no known cause for their gut symptoms. It is concluded that gastro-enteritis caused by Aeromonas is related to species and to production of cytotoxin.

Aeromonas↗
PubMed1986

Megaloblastic anaemia due to vitamin B12 deficiency caused by small intestinal bacterial overgrowth: possible role of vitamin B12 analogues.

Megaloblastic anaemia due to bacterial overgrowth of the small intestine is due to vitamin B12 malabsorption. This report describes a patient with bacterial overgrowth of the small intestine who had megaloblastic anaemia and malabsorption of vitamin B12, but persistently normal levels of serum vitamin B12 and normal serum and red cell folate levels. However, there was evidence of vitamin B12 deficiency as shown by an abnormal deoxyuridine suppression test and by the response to treatment with physiological doses of vitamin B12. A relative increase in biologically inactive vitamin B12 analogues may be the explanation for the normal vitamin B12 level in this patient.

Aged↗
PubMed1986

Method for the typing of Clostridium difficile based on polyacrylamide gel electrophoresis of [35S]methionine-labeled proteins.

A typing method for Clostridium difficile based on the incorporation of [35S]methionine into cellular proteins, their separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their visualization by autoradiography is described. On analysis of the radiolabeled-protein profiles, nine distinct groups were observed (A to E and W to Z). The method, which is simple, reproducible, and readily expandable, has been applied in epidemiological studies to demonstrate cross-infection and hospital acquisition of C. difficile.

Adult↗
PubMed1986

Immunoblot analysis of the serological response in invasive Trichosporon beigelii and Blastoschizomyces capitatus infections.

The serological response to Trichosporon sp. was examined by the immunoblot technique. Antibodies to a range of antigens (200 to 16 kilodaltons) were detectable in three patients with invasive Trichosporon beigelii or Blastoschizomyces capitatus infections and 10 uninfected controls. High levels of preexisting antibodies may contribute to the rarity of systemic infections.

Antibodies, Fungal↗
PubMed1986

Immunoblotting to demonstrate antigenic and immunogenic differences among nine standard strains of Clostridium difficile.

The epidemiology of Clostridium difficile-associated disease is being elucidated with the development of typing schemes for the organism. We recently described a new typing scheme based on the incorporation of [35S]methionine into bacterial proteins followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. Nine standard strains were identified. We report here some observations on the antigenic differences among these nine strains when studied by immunoblotting. Type-specific rabbit antiserum was raised against each of the nine standard strains. Immunoblotting of the strains with these antisera demonstrated, in addition to the presence of shared, common proteins, a type-specific response with homologous antisera. When [35S]methionine-labeled C. difficile proteins were immunoblotted with homologous and heterologous antisera, both the immunoblots and the autoradiographs demonstrated the same strain-specific response. These strain-specific proteins, which have been so useful for epidemiological and typing purposes, were also immunogenic.

Animals↗
PubMed1986

Immunoblot analysis of serological response to Pseudomonas aeruginosa septicaemia in man.

The occurrence of an outbreak of Pseudomonas aeruginosa septicaemias on an oncology ward permitted an analysis of antibody responses in patients who were all orally exposed to the same source of infection. Seven patients became septicaemic. Serial serum samples were immunoblotted against the homologous strain. Responses were compared with those of 16 other patients with septicaemias caused by other strains and 10 healthy controls. All 18 survivors produced increasing IgG or IgA antibody, or both, against a 35,000 dalton band, whereas these antibodies were usually absent or fell in titre in the five fatal cases. These antibodies were also lacking in sera taken just before a patient became septicaemic. This band had the electrophoretic characteristics of the outer membrane porin protein F.

Adolescent↗