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Biomedical subjects

A Eley

Publications and source records attributed to A Eley.

At least 37 records · Page 2Linked to original sources
PubMed1994

Toxin production, adherence and protein expression by clinical Aeromonas spp. isolates in broth and human pooled ileostomy fluid.

The physiological behaviour of clinical Aeromonas spp. isolates was compared following culture in a conventional broth and human pooled ileostomy fluid (PIF). Protein expression was markedly affected by the growth medium, with an overall reduction in whole cell proteins in bacteria grown in ileostomy fluid. In addition, novel outer membrane proteins were produced in PIF but not in broth. The majority of A. hydrophila and A. sobria isolates produced toxin in both broth and PIF, whereas no cytotoxin positive A. caviae were found. Toxin titres were at least two doubling dilutions higher in 40% and 21% of A. hydrophila and A. sobria isolates, respectively, following culture in brain heart infusion broth compared with PIF. Bacterial adherence to Vero and A-549 cells was significantly more common in A. hydrophila (53%) and A. sobria (64%) than in A. caviae (15%) (P < 0.01). We observed increased adherence by 6 aeromonas strains previously classified as adherence-positive, but not by 6 non-adherers, in PIF compared with brain heart infusion broth. The influence of growth medium on the expression of potential virulence determinants by Aeromonas spp. provides a rationale for the use of human ileostomy fluid in future in vitro studies, in order to simulate the nutrient conditions found in vivo.

Aeromonas↗
PubMed1994

Assessment of a chemiluminescent universal probe for taxonomical and epidemiological investigations of Aeromonas sp isolates.

AIMS: To assess a chemiluminescent universal probe for taxonomical and epidemiological investigations of Aeromonas sp isolates. METHODS: Total DNA was extracted from 69 well characterised Aeromonas sp strains and digested with the restriction endonucleases Sma I or Pst I. Following electrophoresis, the resulting fragments were transferred to a nylon membrane where they were hybridised to a commercially available universal probe of 16S + 23S rRNA. The banding patterns (ribotypes) were made visible by enhanced chemiluminescence. RESULTS: Both restriction endonucleases produced heterogeneous ribotypes so that no allocation could be made to any of the control genospecies tested. For A hydrophila and A caviae, however, groups of strains (mostly from the same patient) could be identified by indistinguishable banding patterns. A relatively high proportion (36%) of A sobria strains were non-typable. CONCLUSIONS: Although this universal chemiluminescent probe is user friendly, it is unsuitable for taxonomical investigations of Aeromonas sp. It is useful in epidemiological studies of A hydrophila and A caviae, but is of less value for A sobria.

Adult↗
PubMed1993

Fusobacteria: new taxonomy and related diseases.

Fusobacteria are anaerobic gram-negative bacilli. Since the first reports in the late nineteenth century, various names have been applied to these organisms, sometimes with the same name being applied to different species. More recently, not only have there been changes to the nomenclature, but also attempts to differentiate between species which are believed to be either pathogenic or commensal or both. Because of their asaccharolytic nature, and a general paucity of positive results in routine biochemical tests, laboratory identification of the fusobacteria has been difficult. However, the application of novel molecular biological techniques to taxonomy has established a number of new species, together with the subspeciation of Fusobacterium necrophorum and F. nucleatum, and provided new methods for identification. The involvement of fusobacteria in a wide spectrum of human infections causing tissue necrosis and septicaemia has long been recognised, and, more recently, their importance in intra-amniotic infections, premature labour and tropical ulcers has been reported.

Animals↗
PubMed1992

Detection of Chlamydia trachomatis by the polymerase chain reaction in young patients with acute epididymitis.

Specimens from 11 patients presenting with acute epididymitis were tested for the presence of Chlamydia trachomatis by an enzyme immunoassay (EIA), growth in McCoy cells and the polymerase chain reaction (PCR), and for other microorganisms by standard laboratory techniques. Chlamydia trachomatis urethral infection was detected in four patients by tissue culture, in three patients by EIA and in nine patients by PCR. These findings confirm the usually low detection rate of Chlamydia trachomatis by conventional tissue culture and EIA. Detection by PCR indicated both the diagnostic value of this technique and the importance of this organism in epididymitis.

Acute Disease↗
PubMed1992

Characterisation of non-pigmented species of the genus Prevotella by polyacrylamide gel electrophoresis.

Gram-negative anaerobic bacilli previously known as the melaninogenicus-oralis group of Bacteroides have been assigned to a new genus, Prevotella. The non-pigmented members of this genus share several general characteristics and cannot be readily distinguished by routine tests. A polyacrylamide slab gel electrophoresis procedure, with visual analysis of protein patterns, was used to compare cellular protein patterns from clinical isolates with those from collection (reference) strains. Reference strains of P. oralis, P. veroralis, P. buccalis, P. oris, P. buccae, P. zoogleoformans, P. bivia, P. disiens, P. oulora, B. (P.) capillus and B. (P.) pentosaceus, and 91 non-pigmented isolates from patients with adult periodontal disease were examined by conventional biochemical tests, gas-liquid chromatography (GLC) and enzyme tests, and whole-cell protein profiles were obtained by SDS-PAGE. There was close correlation between patterns of results in biochemical and GLC tests and the SDS-PAGE profiles, and the species were readily distinguished in SDS-PAGE. The periodontal isolates were assigned to 10 groups by conventional test reaction patterns and nine groups by SDS-PAGE; the profiles of 79 isolates corresponded to those of seven species reference strains. By SDS-PAGE, clinical isolates of P. buccae (42 isolates) and P. oralis (eight isolates) showed good similarity with reference strains. However, for P. veroralis (15), P. oris (7), P. bivia (4), P. zoogleoformans (2) and P. buccalis (1), clinical isolates showed some minor variations from reference strains. Twelve isolates remained undesignated in SDS-PAGE analysis. Variant SDS-PAGE profiles divided clinical isolates of P. buccae into two subgroups and those of P. veroralis into five subgroups.

Adult↗
PubMed1992

Restriction endonuclease analysis and ribotyping differentiate genital and nongenital strains of Bacteroides ureolyticus.

Thirty-three clinical isolates from male nongonococcal urethritis and 28 isolates from soft tissue infections and ulcers were identified as Bacteroides ureolyticus by conventional bacteriological tests and were compared with five reference strains of the species. Whole-cell proteins from these clinical isolates and the reference strains were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The majority of the strains from the two sources could be divided into five different groups, named phenons I to V; phenons I to IV have been described previously by others, while phenon V has been described recently by us. Digestion of chromosomal DNA from 16 of the clinical isolates (including strains representative of each of the five SDS-PAGE phenons) and the five reference strains was attempted with restriction endonucleases EcoRI, PstI, SmaI, and HindIII. After electrophoresis in agarose gels, good digestion was observed with HindIII only, and 12 different banding patterns (restriction endonuclease analysis [REA] profiles) were obtained for the 19 strains digested; one nongonococcal urethritis isolate and one reference strain did not show any digestion. From the agarose gels, HindIII-digested fragments of DNA were transferred to nylon membranes by use of vacuum blotting and subjected to hybridization with 32P-labelled 16S-23S rRNA from Escherichia coli. The resultant pattern of bands (ribotypes), which depends on the restriction fragment length polymorphisms in the rRNA genes, was used as a measure of genomic variation within the species. In total, 13 different ribotypes were obtained for the 19 strains. For some strains, good correlation was achieved among the SDS-PAGE phenons, REA profiles, and ribotypes. However, for others, REA analysis and ribotyping were able to discriminate between strains which shared the same SDS-PAGE phenon. Interestingly, these two techniques of DNA characterization were able to differentiate between isolates from the genital tract and those associated with soft tissue infections and ulcers.

Bacterial Proteins↗
PubMed1992

Aeromonas spp as a potential cause of diarrhoea in children.

AIMS: To determine the prevalence of Aeromonas spp in the faeces of children and the association with symptoms of gastroenteritis. METHODS: Faecal specimens (n = 1026) were cultured for Aeromonas spp using three selective media and an enrichment broth at both 30 degrees C and 37 degrees C. The isolation of Aeromonas spp was correlated with symptoms of gastroenteritis, previous antibiotic use, and environmental temperature. RESULTS: Aeromonas spp (n = 28) from 26 (2.5%) patients were recovered. Bile salt, Irgasan, and brilliant green agar was the most efficient selective culture medium. Eleven of the patients had symptoms of gastroenteritis, usually mild diarrhoea of two to three days' duration, in the absence of other recognised enteropathogens. A caviae was a particularly frequent isolate (nine out of 11 cases) in symptomatic individuals. Only one out of seven Aeromonas spp recovered by enrichment culture alone was possibly associated with symptoms of gastroenteritis. There was a close correlation between the environmental temperature and isolation of Aeromonas spp. CONCLUSIONS: Aeromonas spp and particularly A caviae may cause gastroenteritis in children, most often during warmer months of the year. Culture for these potential enteropathogens could be confined to summer and autumn months. Bile salt, Irgasan, and brilliant green selective agar, but not alkaline peptone water enrichment, is an efficient culture medium for recovering possibly clinically important isolates.

Aeromonas↗
PubMed1992

Phenotypic methods for speciating clinical Aeromonas isolates.

AIMS: To establish the suitability of currently available phenotypic methods for speciation of clinical Aeromonas isolates in diagnostic microbiology laboratories. METHODS: Using 62 Aeromonas spp, three schemes based on biochemical reactions were compared: a series of conventional tests; a system based on the suicide phenomenon, comprising two tubes in total; and a commercially available test, API 20 NE, augmented with a plate assay for beta haemolysin production. The whole cell and outer membrane protein (OMP) profiles of strains were examined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS PAGE), according to the results of the above schemes, to determine the intra-species homogeneity. RESULTS: Ninety per cent of strains were identified satisfactorily according to conventional criteria. For these strains, agreement was obtained using the suicide phenomenon and API schemes in 93% and 88% of cases, respectively. The three schemes concurred for 82% of strains. Whole cell protein profiles were unsuitable for comparing strains within a species. However, OMP patterns were similar for 89% of A caviae and 63% of A hydrophila. CONCLUSION: Phenospeciation of clinical Aeromonas isolates by the scheme based on the suicide phenomenon is simple to perform and accurate, and suitable for use in the diagnostic laboratory. OMP profiles are potentially useful for confirming the identity of A caviae and most A hydrophila, but not A sobria.

Aeromonas↗