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David Tompkins

Publications and source records attributed to David Tompkins.

5 recordsLinked to original sources
PubMed2006

Investigating vomiting and/or bloody diarrhoea in Campylobacter jejuni infection.

Campylobacter jejuni infection frequently presents as acute enteritis with diarrhoea, malaise, fever and abdominal pain. Vomiting and bloody diarrhoea are reported less frequently. To investigate potential host, micro-organism or environmental factors that might explain the different clinical presentations, the features of laboratory-confirmed Campylobacter jejuni cases presenting with vomiting and/or bloody diarrhoea were compared with cases who did not report either clinical manifestation. Single variable analysis and logistic regression were employed. Explanatory variables included food, water and environmental risks. Cases who reported vomiting and/or bloody diarrhoea tended to suffer a longer illness and were more likely to require hospital admission. Independent risks identified were being a child, female gender, consumption of poultry other than chicken, pre-packed sandwiches and sausages, and reported engineering work or problems with drinking-water supply. A dose-response relationship with vomiting and/or bloody diarrhoea and increasing daily consumption of unboiled tap water was observed also. Vomiting and/or bloody diarrhoea characterized the more severe end of the disease spectrum and might relate to host susceptibility and/or infective dose. The role of unboiled tap water as a potential source of C. jejuni infection in England and Wales requires further investigation.

Adolescent↗
PubMed2006

Detection of enteroaggregative Escherichia coli in faecal samples from patients in the community with diarrhoea.

The aim of this study was to assess the usefulness of a multiplex PCR assay targeting the aat, aaiA and astA genes for the detection of typical and atypical enteroaggregative Escherichia coli (EAEC) in bacterial cultures from faecal samples from patients with community-acquired diarrhoea. The isolates harbouring these genes were also tested using the HEp-2 cell-adhesion assay to clarify their EAEC status. aat, aai or astA was found in E. coli faecal isolates from 39 (7.8 %) of 500 patients, and 20 of these strains adhered to HEp-2 cells in a pattern characteristic of EAEC. Eight isolates carrying the aai or astA gene but not the aat gene were shown to be HEp-2 cell test positive, although 12 strains with this genotype were HEp-2 cell test negative. Using the HEp-2 adhesion assay as the gold standard, the addition of primers detecting aaiA and astA to the aat PCR increased the number of EAEC isolates detected, but identified strains of E. coli that were not EAEC. The variety of genotypes exhibiting aggregative adherence highlights the problems associated with developing a molecular diagnostic test for EAEC. This PCR assay detects a variety of strains exhibiting characteristics of the EAEC group, making it a useful tool for identifying both typical and atypical EAEC.

Adhesins, Escherichia coli↗
PubMed2004

Analysis of geospecific markers for Helicobacter pylori variants in patients from Japan and Nigeria by triple-locus nucleotide sequence typing.

Human migrations and geographical separation over long periods may have resulted in ecologically distinct populations of Helicobacter pylori infecting individuals in different continents. This study used nucleotide sequence analysis with the aim of defining population-specific genomic motifs in isolates from East Asian and African dyspeptic patients. Sequences of internal fragments (542-627 bp) of three housekeeping genes (ureI, ahpC and atpA) were analysed for 85 isolates from individuals in Japan and China (30 isolates), Nigeria and South Africa (14 isolates), the United Kingdom (32 isolates), and nine miscellaneous reference strains. Phylogenetic analyses showed a high degree of intra-set relatedness amongst sequences from the Japanese and Nigerian isolates, with each robustly segregated as distinct lineages irrespective of cagA presence and vacA allelic type. All strains had unique combined sequence types except for identical paired (antrum/corpus) isolates. Population-specific polymorphisms were identified within each gene which were combined to provide unique motifs defining the Japanese and Nigerian regional populations. The alleles were present at variable frequencies in UK and South African isolates. The findings provide unique evidence of positive selection for conserved nucleotide sites linked to the geographical separation in Japan of a strain subpopulation for which we propose the designation H. pylori geovar 'orientalis'.

Adult↗
PubMed2002

Helicobacter pylori susceptibility testing by disc diffusion.

The bacterium Helicobacter pylori is found in c. 40% of the population and is responsible for the development of duodenal disease. Triple treatment with a proton-pump inhibitor or bismuth salt plus two antibiotics is now commonplace in all patients diagnosed. As antibiotic resistance reduces treatment efficacy, it is time to consider routine susceptibility testing to guide individual patient treatment and surveillance of antibiotic resistance. There are no published nationally agreed standards for disc diffusion testing of H. pylori. After reviewing the literature, we recommend the following method for disc diffusion tests. A suspension of cultures < or = 4 days old equivalent to McFarland Standard no. 4 (10(8) cfu/mL) should be used on Mueller-Hinton or Columbia agar base with 5-10% blood, using a metronidazole disc strength of 5 Ig and a clarithromycin disc strength of 2 microg. Anaerobic pre-incubation of plates is unnecessary. A H. pylori control susceptible to metronidazole (e.g. NCTC 12822) should be used. Zone sizes with the Mueller-Hinton agar base for metronidazole testing are <16 mm resistant, 16-21 mm intermediate and >21 mm susceptible. We suggest that isolates in the intermediate zone should be re-tested by Etest. Zone sizes with the Columbia agar base for metronidazole testing are <10 mm resistant and > or = 10 mm susceptible. Co-infection with two strains, which may be a mixture of isolates susceptible and resistant to metronidazole leading to conflicting susceptibility results, occurs in 5-10% of patients. Zone sizes with Mueller-Hinton agar and Columbia blood agar for clarithromycin testing are resistant no zone and susceptible any zone.

Anaerobiosis↗