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Biomedical subjects

M Cafferkey

Publications and source records attributed to M Cafferkey.

8 recordsLinked to original sources

Evaluation of different solid media used for cultivation of Helicobacter (Campylobacter) pylori.

The ability of nine blood containing media to support the growth of H. pylori was compared. Eighteen strains of H. pylori isolated from antral biopsies were cultivated in two dilutions, for colony counts on the media to be tested. Columbia base chocolate agar without additives was found to be the best medium for growth of H. pylori. However, all other fresh blood containing media also supported the growth of this organism satisfactorily.

Blood

The effect of bile acids on the growth and adherence of Helicobacter pylori.

Bile reflux gastritis occurs in the absence of Helicobacter pylori (H. pylori). The aim of this study was to see if the bile acids cheno or ursodeoxycholic acid affected the growth or adherence of H. pylori in vitro. Twenty-seven strains growth were inhibited by 0.1% chenodeoxycholic acid whereas only 11 out of the 27 were inhibited by 0.1% ursodeoxycholic acid. Growth was totally inhibited by a combination of 0.05% chenodeoxycholic acid +0.05% ursodeoxycholic acid. Chenodeoxycholic acid was a more effective inhibitor of adherence in that the number inhibited and percentage inhibition were greater than with ursodeoxycholic acid. Bile salts might be useful in the treatment of H. pylori infection.

Animals

Infection of Waldeyer's ring: value of pernasal retropharyngeal swabs.

The value of pernasal retropharyngeal swabs in chronic adenoid and tonsillar disease was assessed in a prospective study involving 52 patients. Prior to adenoidectomy (34 patients) or adenotonsillectomy (17 patients), pernasal and tonsillar swabs were taken and the culture compared to the bacteriology profile obtained in the adenoid and tonsil tissue following surgery. The pernasal swab correctly identified 76% of pathogens isolated in the adenoid tissue. In addition, pernasal swabs forecast the presence of pathogens in 64% of core tonsil specimens, compared to an accuracy of 38% when superficial tonsil swabs were compared to the microbes in the deep tonsil. H. influenzae was the predominant organism isolated in all cultures. Our results clearly demonstrate that pernasal swabs give a representative picture of the adenoid bacterial content. Pernasal swabs are also superior to superficial tonsil swabs in indicating the deep tonsillar organisms.

Adenoidectomy

Yersinia enterocolitica aroA mutants as carriers of the B subunit of the Escherichia coli heat-labile enterotoxin to the murine immune system.

Plasmid p5F which directs the expression of the Escherichia coli heat-labile enterotoxin B subunit (LT-B) from the ptac promoter was introduced into the attenuated Yersinia enterocolitica O:8 aroA mutant strain YAM.1. YAM.1 (p5F) expressed high levels of cell-associated and secreted LT-B in a stable fashion when grown on normal laboratory medium. The strain was used as a live oral vaccine in BALB/c mice and vaccinated mice developed high levels of gut-associated and systemic antibodies to both LT-B and the lipopolysaccharide (LPS) of the vaccine strain. Anti-LT-B and anti-LPS responses in the sera were predominantly of the IgG class whereas gut-associated antibodies were predominantly IgA. ELISPOT assays carried out on selected tissues prepared from vaccinated mice showed significant numbers of cells synthesising IgG and IgA antibodies to LT-B. These results show that Y. enterocolitica aroA mutants can be used effectively as carriers of heterologous antigens to the murine immune system.

Animals

Cloning and characterisation of the serC and aroA genes of Yersinia enterocolitica, and construction of an aroA mutant.

A gene library of Yersinia enterocolitica 8081 was constructed in the cosmid vector pHC79. Recombinants containing the aroA gene, encoding 5-enolpyruvylshikimate 3-phosphate synthase, were identified by complementation of the aroA mutation in Escherichia coli K-12 strain AB2829. All six recombinant plasmids which complemented aroA also complemented the serC mutation in E. coli K-12 strain KL282. Tn5 mutagenesis suggested serC encoding 3-phosphoserine aminotransferase was the proximal gene in an operon with aroA. The nucleotide sequence of a 3-kb HindII-EcoRV fragment encoding the two genes was determined. The serC and aroA open reading frames contain 362 and 428 codons, respectively, and the deduced amino acid sequences share 78% and 81% homology, respectively, with the corresponding E. coli genes. Sequence inspection revealed no obvious terminators or promoters in the intergenic region. The cloned Y. enterocolitica aroA gene was inactivated in vitro and reintroduced into the parental Y. enterocolitica 8081 strain using the suicide vector pJM703.1. Stable aroA insertion mutants of Y. enterocolitica were isolated.

3-Phosphoshikimate 1-Carboxyvinyltransferase

Virulence, persistence, and immunogenicity of Yersinia enterocolitica O:8 aroA mutants.

The virulent Yersinia enterocolitica strain 8081 killed BALB/c mice within 5 days of oral infection with a 50% lethal dose of log10 7.1, whereas an aroA mutant of 8081, YAM.1, and the plasmidless variant 8081c failed to kill mice. Unlike 8081, YAM.1 and 8081c did not persist or grow in the Peyer's patches, mesenteric lymph nodes, livers, or spleens of mice. Mice immunized orally with single doses of live YAM.1 were poorly protected against a lethal 8081 challenge, whereas mice immunized with three doses of YAM.1 were moderately well protected.

Administration, Oral

Vancomycin toxicity: a prospective study.

A prospective study of 34 patients treated with 39 courses of intravenous vancomycin, was undertaken in order to assess toxicity. Six patients received vancomycin alone and 27 courses were associated with aminoglycoside administration either concurrently or within two weeks of the first dose of vancomycin. Hearing loss was slight and uncommon; patients were unaware of its occurrence. Tinnitus and dizziness was noted by two patients and resolved on withdrawal of vancomycin. Diminution of renal function was seen both during (7%) and after (9%) vancomycin therapy. A striking feature of these patients with renal deterioration was the severity of their underlying disease. No evidence of synergistic toxicity between vancomycin and aminoglycosides was seen.

Adolescent