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S R Heard

Publications and source records attributed to S R Heard.

At least 19 recordsLinked to original sources
PubMed1994

Assessment of two methods for rapid intrapartum detection of vaginal group B streptococcal colonisation.

AIMS: To compare two methods for the rapid detection of intrapartum vaginal carriage of group B streptococci (Streptococcus agalactiae) with standard culture techniques and to establish their suitability for routine use. METHODS: Vaginal swabs from 266 patients in labour were incubated in glucose broth in an anaerobic atmosphere for four to six hours. The Wellcogen Strep B latex particle agglutination test kit was subsequently used for antigen detection. In the second part of the study swabs from 117 women were assessed for the presence of group B streptococci using the ICON STREP B immuno-concentration assay (Hybritech). Both methods were compared with standard semiquantitative culture on Columbia horse blood agar and Islam's medium. RESULTS: In the first study vaginal carriage of group B streptococci was shown in 38 of 266 (14.3%) patients by culture. Latex particle agglutination with the Wellcogen kit detected 30 of these positive results (sensitivity 78.9%, specificity 100%). In those patients with moderate to heavy colonisation (> 10(4) colony forming units per millilitre) antigen was detected in all (26/26) culture positive patients (sensitivity 100%, specificity 100%). In the second study 16 (13.7%) patients were culture positive. The ICON test detected 11 positive results (sensitivity 68.8%, specificity 100%) and for heavy colonisation (10(5) cfu/ml) detected nine of nine cases (sensitivity 100%, specificity 100%). The ICON test took 10 to 15 minutes to perform. CONCLUSION: These tests are potentially useful for the rapid detection of group B streptococci vaginal colonisation in labour, particularly heavy colonisation. Both tests are insufficiently sensitive to replace standard culture methods.

Agglutination Tests↗
PubMed1993

Characterisation of Clostridium difficile strains by polymerase chain reaction with toxin A- and B-specific primers.

A total of 218 Clostridium difficile strains was examined for production of toxin A by ELISA, production of toxin B by a cytotoxin assay and the presence of toxin A and B gene-associated sequences by the polymerase chain reaction (PCR). After saturation amplification with toxin B-specific primers, the characteristic amplification product (591 bp) was detected in all 184 toxigenic strains examined. PCR with toxin A-specific primers gave positive results with all but one of the toxigenic strains. By contrast, PCR with toxin A- and toxin B-specific primers yielded negative results with all 34 non-toxigenic strains tested. This suggests that PCR detection of either the toxin A or B gene is a good indication of toxin production. PCR did not require DNA extraction or hybridisation and was convenient, sensitive and rapid. Toxigenic C. difficile could be detected in mixed cultures, suggesting a role for PCR in the identification of toxigenic C. difficile in primary culture.

Bacterial Proteins↗
PubMed1993

Immunoblotting of streptococcal antigens in guttate psoriasis.

Guttate psoriasis may be precipitated by acute streptococcal infection, usually of the upper respiratory tract. We have studied the immune response to streptococci in 26 patients presenting with a first or recurrent episode of acute guttate psoriasis (AGP), using immunoblotting. Eighteen of 26 patients studied had a demonstrable response to a wide range of streptococcal antigens using this approach, compared with 14 of 26 patients who demonstrated a response using more conventional antistreptococcal antibody tests. Patients with AGP had a significantly higher antibody detection score using immunoblotting than did control subjects (P < 0.005). We conclude that immunoblotting is a useful technique in studying this condition and may be of benefit in exploring the immunopathogenesis of AGP.

Adult↗
PubMed1993

New phenotypic typing scheme for group B streptococci.

AIMS: To develop a new typing system for group B streptococci based on 35S-methionine-labelled protein profiles of bacterial proteins. METHODS: 377 clinical isolates of group B streptococci were examined by incorporation of 35S-methionine into bacterial proteins under strict anaerobic conditions. After sodium dodecylsulphate-polyacrylamide gel electrophoresis, autoradiography was performed. The patterns produced were visually analysed and categorised into clusters of organisms based on the pattern of band production between 32-46 kilodaltons. RESULTS: 294 of the typed strains classified into seven different groups designated a-g. 32 strains failed to incorporate 35S-methionine sufficiently to be grouped and 11 strains did not fall into one of the seven identified groups. Typability, reproducibility, and discrimination of the system was evident. CONCLUSIONS: This typing system may help to distinguish between colonising and invasive strains of the organism.

Autoradiography↗
PubMed1993

Detection of the C protein gene among group B streptococci using PCR.

AIM: To develop a polymerase chain reaction (PCR) for the specific detection of the C protein gene in strains of group B Streptococcus. METHODS: A single primer pair derived from the nucleotide sequence of the IgA binding beta antigen of the C protein complex permitted the specific amplification of a 592 base pair DNA fragment from the C protein gene. After 35 cycles of amplification this product could be detected by agarose gel electrophoresis. Southern blot hybridisation confirmed that this product was the C protein gene. RESULTS: PCR detected the C protein gene in 75 (63%) of 119 strains of group B streptococci analysed. The product was not detected in other Gram positive organisms, showing that this PCR assay was highly specific. The sensitivity of the assay was satisfactory to a dilution of 1 in 10,000 of extracted DNA. CONCLUSIONS: The C protein of group B streptococci is associated with neonatal sepsis. The specific detection of the C protein gene by PCR may help identify which strains are likely to be associated with infection by the organism.

Bacterial Proteins↗
PubMed1992

Use of the ASI titanium stent in the management of bladder outflow obstruction due to benign prostatic hyperplasia.

An expandable titanium intraprostatic stent was inserted into 30 patients with infravesical obstruction due to benign prostatic hyperplasia (BPH). All of the men were considered unsuitable for transurethral resection of the prostate as a result of comorbid conditions. In 25 patients effective micturition was reestablished with this technique. In 21 of these men, who have been followed for longer than 1 year, the mean maximum flow rate at 1 year was 10.8 ml. per second and the mean residual urine was 56 ml. Although urinary tract infections occurred subsequent to stent insertion in 10 individuals, these resolved after appropriate antibiotic treatment and no stents have had to be removed for this reason. Followup cystoscopy or examination by electron microscopy of those stents that have been removed has shown partial epithelialization of the stent surface in a proportion of patients, and a minor degree of incrustation occurred in 1 case. We conclude that an expandable intraprostatic titanium stent is an acceptable alternative to transurethral resection of the prostate or long-term catheterization in this particular group of high risk patients.

Aged↗
PubMed1992

Pneumococcal endocarditis and disseminated infection.

A 61 year old woman presented with back pain and clinical signs of meningitis. Pleocytosis in the cerebrospinal fluid was found, but although Streptococcus pneumoniae was cultured from her blood it failed to grow from the cerebrospinal fluid. An echocardiogram detected vegetations on the mitral valve and a lesion at S1/S2 was demonstrated on a bone scan. Treatment for one month with benzylpenicillin (1200 mg four hourly) was successful for both the cardiac and neurological components of her infection, but her back pain only resolved after treatment was changed to clindamycin. The clinical presentation and metastatic spread of the S pneumoniae infection is much more commonly seen in the context of S aureus endocarditis. It is rare for the pneumococcus to be associated with endocarditis and when it is mortality is usually high. This case shows the metastatic potential of the organism and the requirement for appropriate antibiotics with regard not only to the sensitivity of the organism, but also for the site of infection.

Bacteremia↗
PubMed1988

Tuberculosis presenting as laryngeal stridor in a child.

A three and a half-year-old boy developed stridor after insertion of grommets for bilateral secretory otitis media. Despite treatment with steroids systemically and locally, antibiotics and an antihistamine, the stridor worsened. Microlaryngotracheobronchoscopy (MLB) demonstrated laryngeal granulations, in which, by auramine and Ziehl-Neelsen staining, acid-fast bacilli were seen, and from which subsequently Mycobacterium tuberculosis grew in culture. Following the MLB the child became comatosed and a clinical diagnosis of tuberculosis involving the central nervous system was made. Despite quadruple antituberculous chemotherapy he died 8 days later. A Mantoux test was negative and a chest radiograph was normal. Acid-fast bacilli were not demonstrated on repeated examinations of cerebrospinal fluid, nor were they grown ante mortem or post mortem from samples of cerebrospinal fluid.

Child, Preschool↗
PubMed1988

Clostridium difficile infection in patients with haematological malignant disease. Risk factors, faecal toxins and pathogenic strains.

Two hundred and forty-eight patients from shared oncology and general medical wards were prospectively studied over a 6-month period for carriage of Clostridium difficile during an outbreak of clinical disease with an epidemic strain of the organism. Risk factors for infection were assessed. Acute leukaemia and/or its treatment were identified as significantly increasing the risk of infection. The relationship between the type of C. difficile isolated (as defined by a typing system based on the incorporation of [35S]methionine into bacterial proteins followed by gel electrophoresis), the presence of faecal toxins A and B and clinical symptoms were analysed. Carriage of the epidemic strain, type X, had a significant association with symptoms amongst oncology patients, with two thirds of these patients having detectable faecal toxin A and one third detectable faecal toxin B. During an outbreak of C. difficile-associated disease, typing the organism and assaying for both faecal toxins in symptomatic patients may be of benefit in determining which patients require specific, urgent treatment.

Adolescent↗
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

Teaching medical ethics symposium. A student-led approach to teaching.

It is increasingly agreed that ethics has a place in undergraduate medical education. There is, however, debate about how it should be taught, and by whom. We present our experience of teaching ethics in a general practice module over six years. During this period there has been a shift from a teacher-centred to a student-centred approach in which students choose ethical issues to explore within a framework provided. The issues raised are discussed with examples, and the future directions of our ethics teaching outlined.

Bioethical Issues↗
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↗
PubMed1985

Gastrointestinal colonization and septicaemia with Pseudomonas aeruginosa due to contaminated thymol mouthwash in immunocompromised patients.

An outbreak of septicaemia with Pseudomonas aeruginosa amongst adult men with haematological malignancy involved eight patients on the same ward during a period of 5 weeks. The strains isolated from blood cultures from seven patients were indistinguishable by conventional typing methods. Thymol mouthwash which had been made up and distributed in communal jugs was found to be contaminated with the epidemic strain and was the likely source for this outbreak. A high rate of gastrointestinal colonization with the epidemic strain was found in the patients receiving the contaminated mouthwash. Only those patients with prolonged severe leucopenia developed septicaemia. Communal medications are an unnecessary hazard, particularly in oncology wards.

Adolescent↗