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Biomedical subjects

A G Taylor

Publications and source records attributed to A G Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1989

The use of monoclonal antibodies against Listeria monocytogenes in a direct immunofluorescence technique for the rapid presumptive identification and direct demonstration of Listeria in food.

Two monoclonal antibodies which recognise serogroup specific cell surface antigens of Listeria monocytogenes are described. The antibodies were specific for Listeria (i.e. did not react with 87 strains of bacteria from 14 other genera). In an indirect immunofluorescent test the antibodies had similar specificities when tested against strains of L. monocytogenes from human infections grown under a number of different growth conditions, and serological reference strains. A direct immunofluorescent antibody test was developed, and similar specificities of the antibodies found with strains of Listeria which had been isolated from food and grown under 2 different growth conditions. This technique is also used to directly demonstrate Listeria in soft cheese.

Animals↗
PubMed1989

Typing of Listeria monocytogenes for epidemiological studies using DNA probes.

We have investigated the possibility of using restriction fragment length polymorphisms (RFLPs) to distinguish different strains of Listeria monocytogenes. Cloned DNA fragments (probes) were selected from a bacteriophage lambda gene library of L. monocytogenes (L1428). DNAs from two lambda clones consisting of a total of approximately 20kb of probe DNA were labelled with biotinylated dUTP for use in these experiments. The criteria for probe selection were the ability both to hybridise with all strains of L. monocytogenes and to reveal RFLPs. Southern blots of restriction endonuclease (Nci I) digested DNAs from test strains of L. monocytogenes were hybridized to the probe. Following washing, biotinylated probe remaining bound to the filters was detected using the Blugene reagents (Gibco/BRL). Under these experimental conditions strain-specific restriction fragments were revealed. We have examined 64 strains of L. monocytogenes belonging to serogroup 1/2 which were not apparently epidemiologically associated and 19 patterns were observed. Epidemiologically related strains gave identical patterns of restriction fragments.

Bacterial Typing Techniques↗
PubMed1988

Identification of species of the genus Legionella using a cloned rRNA gene from Legionella pneumophila.

A cloned EcoRI fragment from Legionella pneumophila, which includes 16S and 23S rRNA genes, was used to identify bacteria belonging to the genus Legionella by hybridization to a series of species specific restriction fragments. Examination of the type strains of 28 species of legionellae gave different band patterns in every case. When further isolates of these species were tested the patterns obtained were usually either identical, or very similar, to those of the respective type strains. Thirty-one coded isolates were examined and of these 29 were allocated to the correct species. The remaining strains (a non-Legionella and a L. pneumophila) could not be identified using this technique. The rRNA gene probe method should be of great value in the identification of legionellae, particularly for those species which are at present very difficult to distinguish serologically.

Cloning, Molecular↗
PubMed1988

Serological diversity within the species Legionella spiritensis.

A strain of Legionella isolated from the environment which could not initially be identified was shown by restriction fragment length polymorphisms to be a Legionella spiritensis. This was confirmed by DNA homology studies, cell wall fatty acid composition and isoprenoid quinone analysis. This strain, which is only the second reported representative of the species, was shown to be serologically distinct from the type strain of L. spiritensis and all other serogroups of Legionella.

Antigenic Variation↗
PubMed1988

Monoclonal antibodies show Listeria monocytogenes in necropsy tissue samples.

Stable mouse monoclonal hybridoma cell lines secreting antibodies against Listeria monocytogenes were produced. Antibodies from two of these cell lines (designated CL2 and CL17) have been partially characterised. The specificities of these antibodies were assessed using indirect immunofluorescence antibody tests and L monocytogenes (166 strains) grown in vitro, other species of Listeria (21 strains), and bacteria from 14 other genera (87 strains). The antibodies were found to be specific for Listeria, and when used in combination, reacted with almost all strains of L monocytogenes. A simple and rapid direct immunofluorescence technique was developed, and the presence of L monocytogenes was shown in necropsy tissue from three patients where listeriosis had been confirmed by isolation of the bacterium. Bacteria were also confirmed using one of these antibodies in necropsy tissue from one further patient in whom listeriosis was suspected, but not confirmed by the cultivation of L monocytogenes.

Adult↗
PubMed1987

Evaluation of sensitivity of two serological tests for diagnosing pneumonia caused by Legionella pneumophila serogroup 1.

The sensitivity of an indirect immunofluorescence antibody test (IFAT) and a rapid microagglutination test (RMAT) for the diagnosis of Legionnaires' disease caused by Legionella pneumophila serogroup 1 was evaluated using serum specimens from 119 patients with bacteriologically confirmed infections. The sensitivity of both assays was found to be about 80%. In addition, antibody titres suggestive of L pneumophila infection were found in 40% of patients in the first week after admission to hospital. These data show that both assays can be used with confidence in the early diagnosis of Legionnaires' disease.

Adolescent↗
PubMed1986

Aspects of the epidemiology of human Listeria monocytogenes infections in Britain 1967-1984; the use of serotyping and phage typing.

Strains of Listeria monocytogenes from 475 cases of human listeriosis collected during 1967-1984, belonged to one of three serogroups (1/2, 3 or 4). They were phage typed with a set of 28 phages to investigate three aspects of the epidemiology of listeriosis. Three patients each had two episodes of listeriosis, 3 months to 2 years apart, with strains of the same serogroup and indistinguishable by phage typing. Ten episodes of possible cross-infection between pairs of neonates in the same hospital occurred; the first baby was ill at or within 1 day of birth, and the second baby became ill 8-12 days after contact with the first. In each pair the L. monocytogenes strains were of the same serogroup and indistinguishable by phage typing. In three clusters of cases there may have been a common source of infection. L. monocytogenes strains from 10 of 11 cases of listeriosis in the Carlisle area in Jul.-Dec. 1981 were of the same serogroup; nine strains were non-phage-typable. The second cluster involved four adults treated at one hospital and the third a pair of neonates who were ill shortly after birth. In each cluster, strains were of the same serogroup, and were indistinguishable by phage typing. These last two clusters occurred during a short period when an unusually high proportion of strains from all cases of human listeriosis in Britain were indistinguishable by phage typing from the cluster strains, suggesting the possibility of common source infection.

Adult↗
PubMed1985

A multi-centre study on the phage typing of Listeria monocytogenes.

The aim of this multicenter study was to determine and to standardize methods in order to have common basis for comparing results of phage typing of Listeria monocytogenes. Using a common set of Listeria strains, a standardized method, including media, bacterial growth conditions, application of viruses and reading of lytic reactions, was established. 29 bacteriophages were selected according to their host range. This phage typing system allowed phagovar determination of 54% of the serogroup 1/2 strains and 77% of the serogroup 4 strains of L. monocytogenes.

Bacteriophage Typing↗