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J T Magee

Publications and source records attributed to J T Magee.

54 records · Page 3Linked to original sources
PubMed1992

A pyrolysis mass spectrometry study of the non-pigmented Prevotella species.

Collection strains (21) and non-pigmented clinical isolates (96) provisionally identified as Prevotella spp. were classified numerically on the basis of pyrolysis mass spectrometry (PMS) data and reaction patterns in conventional tests (CTRPs) for volatile and non-volatile fatty acids, pre-formed enzymes and biochemical activity. PMS and CTRP classifications were compared with a previous classification based on visual analysis of SDS-PAGE patterns. Although the order of clusters differed, cross-tabulation of cluster membership revealed strong correlations between classifications. Cluster membership in the PMS classification correlated particularly well with SDS-PAGE results. CTRP clusters corresponded largely to the recognised species of Prevotella, but PMS and SDS-PAGE divided two species into sub-groups: two in P. buccae and five in P. veroralis. The latter subgroups could be discriminated by small but consistent differences in CTRPs. An undesignated, well differentiated cluster of strains appeared closest to the main group of P. buccae strains in PMS and CTRPs. B. (P.) capillus could not be distinguished from P. buccae; these species are regarded as synonymous. Strains of P. zoogleoformans and B. (P.) pentosaceus were well separated from other strains in PMS. A complex comprising clusters of P. disiens, P. oralis, P. veroralis, P. loescheii and a further undesignated group similar to P. melaninogenica was well differentiated from P. buccae and P. oris in PMS; clusters corresponding to P. bivia, P. corporis, P. intermedia and P. denticola formed another complex.

Bacterial Typing Techniques↗
PubMed1991

Typing of Streptococcus pyogenes by pyrolysis mass spectrometry.

Strains of Streptococcus pyogenes from an outbreak in an oncology ward (13) and routine isolates from sporadic cases (6) were examined blind by pyrolysis mass spectrometry (Py-MS), extending previous work on epidemiological typing. This outbreak appeared more complex than one reported previously, but Py-MS and conventional typing results were in complete agreement. The results confirm the potential of Py-MS as a rapid method for identification at strain level in studies of cross infection.

Bacterial Typing Techniques↗
PubMed1990

Micrococcus and Stomatococcus spp. from human infections.

Infections with Micrococcus spp. in six patients and Stomatococcus mucilaginosus in one patient are described. Two of the Micrococcus infections occurred in leukaemic patients with indwelling lines, six episodes occurred in three patients undergoing continuous ambulatory peritoneal dialysis and one occurred in a patient with a ventriculo-peritoneal shunt. Stomatococcus was isolated from fluid draining from a sub-dural haematoma. Colony morphology, oxidase reaction and resistance to nitrofuration were useful in differentiation of micrococci from staphylococci. Incidence and risk factors for micrococcal infections appear similar to those for infections with coagulase-negative staphylococci (CNS), but the literature is confused due to changes in the definitions of these genera.

Adolescent↗
PubMed1990

A three year survey of clinical isolates in the United Kingdom and their antimicrobial susceptibility.

A United Kingdom national survey of clinical isolates and their antimicrobial susceptibility was performed, with 61 participating hospital laboratories, between 1986 and 1989. Each centre used Microbe Base, a commercial suite of micro-computer programs which can record and analyse antimicrobial susceptibility data Informative on 366,853 bacterial isolates and their antimicrobial susceptibility was received from hospital and domiciliary specimens; Candida spp. accounted for a further 9121 isolates. The sites of origin were urine 51%, skin and soft tissue 21%, lower respiratory tract 8%, genital tract 7%, ear, nose and throat 6%, eye 3%, blood 1.5% and faeces 1%. Gram-negative bacteria accounted for 242,307 isolates, the main species were Escherichia coli 48%, Proteus spp. 9%, Pseudomonas spp. 7%, Haemophilus influenzae 6% and Klebsiella spp. 4%. Gram-positive bacteria numbered 124,546 with a predominance of Staphylococcus aureus 42%, beta-haemolytic streptococci 20%, Enterococcus spp. 12%, coagulase negative staphylococci 10% and Streptococcus pneumoniae 5%. All pneumococci were sensitive to penicillin, and methicillin resistant in Staph. aureus was only 2%. Twelve per cent of H. influenzae strains were resistant to ampicillin. There were no significant levels of gentamicin resistance in Gram-negative bacilli.

Drug Resistance, Microbial↗
PubMed1990

A pyrolysis-mass spectrometry study of Corynebacterium spp.

Clinical (66) and collection (38) strains of Corynebacterium spp., including C. jeikeium and CDC group D2, and of Listeria monocytogenes were examined. Conventional characters used in species identification were assessed by a microbiochemical method, and pyrolysis-mass spectrometry (Py-MS) was performed with a Horizon Instruments PYMS 200X. Classification based on Py-MS data yielded clusters that corresponded with species identification and classification groups from conventional data. One small group of clinical strains, homogeneous in conventional tests and Py-MS, comprised isolates from sputum samples from patients undergoing ventilation; they were similar to collection strains of C. renale and C. striatum; the latter species has been implicated in chest infection. Another group, similar to C. minutissimum in both systems, comprised clinical strains isolated from urogenital specimens. L. monocytogenes strains were clearly distinct from Corynebacterium spp. Groups comprising CDC D2 strains and C. jeikeium were resolved, and were similar to other Corynebacterium spp. Two collection strains of C. xerosis were distinct in conventional tests and Py-MS.

Bacterial Typing Techniques↗
PubMed1989

The milk kitchen, Sheffield Children's Hospital, before and after a review.

The milk kitchen at Sheffield Children's Hospital has recently been modernized to update equipment and practices. Microbiological assessments before, during and after this upgrading are described. Limits for viable counts in pasteurized feeds are suggested and the practices adopted to minimize the contamination of feeds are described.

Animals↗
PubMed1989

A pyrolysis mass spectrometry study of fusobacteria.

Strains of fusobacteria (143) were examined by pyrolysis mass spectrometry (Py-MS) with a Horizon Instruments PYMS 200X. Fusobacterium necrogenes, F. necrophorum, F. nucleatum, F. mortiferum, F. varium, F. gonidiaformans, F. naviforme, F. russii and Leptotrichia buccalis were discriminated. Strains of fusobacteria isolated from tropical ulcers, although similar to F. mortiferum in conventional tests, were discriminated from each of these species in Py-MS. Identification of 416 spectra to species level agreed with conventional bacteriological methods in 91.8% of cases, was equivocal in 3.4% and disagreed in 4.8%. Classification based on pyrolysis data resolved groups largely corresponding to the recognised species. However, F. nucleatum strains were divided between two distinct groups. The tropical ulcer strains were resolved as a distinct homogeneous group. Py-MS is a rapid, inexpensive and convenient procedure for characterisation of bacteria, with the capacity for a high throughput of samples, although the initial cost of the apparatus is high.

Fusobacterium↗
PubMed1989

A comparison of Bacteroides ureolyticus isolates from different clinical sources.

Clinical isolates of corroding, gram-negative, anaerobic bacilli (provisionally identified as Bacteroides ureolyticus) from superficial ulcers and soft tissue infections (15), non-gonococcal, non-chlamydial urethritis (12) and adult periodontal disease (14) were compared with reference strains of B. ureolyticus, B. gracilis and Wolinella recta in a series of conventional tests of morphology, biochemical activity, tolerance of dyes and bile salts, and antibiotic sensitivity, gas-liquid chromatographic analysis of metabolic products, and in whole-cell analysis by pyrolysis-mass spectrometry (Py-MS). A numerical taxonomic approach was used with the results of conventional tests and the grouping obtained was compared with that obtained by Py-MS. All the ulcer and soft-tissue isolates and the urethritis isolates were oxidase- and urease-positive and formed a homogeneous set consistent with the reference strain of B. ureolyticus. The dental isolates differed from B. ureolyticus strains and were heterogeneous amongst themselves. None corresponded with the reference strains of B. gracilis or W. recta. The conventional and Py-MS approaches to characterisation produced similar groupings and each distinguished between a single cluster of ulcer-urethritis strains and several clusters of dental strains, although the dendrograms derived from the two approaches differed in the order of the clusters; in the Py-MS dendrogram one subcluster of four dental strains came within the main ulcer-urethritis cluster and a cluster of five ulcer strains was separated as a distinct group.

Bacteroides↗
PubMed1989

Epidemiological typing of Streptococcus pyogenes by pyrolysis mass spectrometry.

Strains of Streptococcus pyogenes from an outbreak of infection on a burns unit (15), a collection of routine isolates from another hospital(12) and isolates from a national survey of throat infections in children in the community(4) were examined blind by pyrolysis-mass spectrometry (Py-MS). The outbreak strains (M22 T12) previously found to give identical typing results in conventional tests, formed a closely similar cluster and were distinct from other hospital and community strains. One hospital and one community strain were loosely associated with this cluster. Another cluster comprised six antibiotic-susceptible strains and two community strains. Six strains did not fall within the clusters; four were antibiotic-resistant strains isolated in hospital, one an antibiotic-resistant strain isolated in the community, and one a susceptible hospital strain. Results show that Py-MS is a potentially valuable method for rapid comparison of strains in studies of infection.

Bacterial Typing Techniques↗
PubMed1988

Pyrolysis mass spectrometry as a method for inter-strain discrimination of Candida albicans.

A claim that Candida albicans strains NCPF 3153 and B311 were identical was investigated. Authentic strains were shown to be distinct (P less than 0.1%) by pyrolysis mass spectrometry (PyMS). Of twelve strains, provided as clones of NCPF 3153, seven were authenticated, one yielded an equivocal result and four were distinct from both NCPF 3153 and B311. Of eight B311 clones, six were authenticated and two yielded equivocal results. Although five non-C. albicans yeast strains were identified as distinct from B311 and NCPF 3153, Torulopsis glabrata NCPF 3240 was identified as B311, and one clinical isolate of C. albicans as NCPF 3153. This could be explained by the specificity of the mathematical analysis for discrimination between the authentic strains.

Candida albicans↗
PubMed1983

Identification of staphylococci by pyrolysis gas-liquid chromatography.

The identification of bacteria by pyrolysis gas-liquid chromatography (PGLC) was evaluated with the genus Staphylococcus. A matrix containing the characteristics of seven species of Staphylococcus was constructed from the results obtained with 42 named strains identified by biochemical methods. An identification program based upon this database was evaluated in tests with 100 isolates of catalase-positive oxidase-negative gram-positive cocci identified by biochemical and PGLC systems. Agreement between the two systems was 90%. Pure cultures of unknown isolates were identified within 30 min by PGLC using a microcomputer data acquisition and analysis program. A taxonomic analysis of the data is presented, and methods for quality control of PGLC, prolongation of column life, and data analysis are described and discussed.

Analysis of Variance↗
PubMed1980

An enzyme-labelled immunosorbent assay for Brucella abortus antibodies.

An enzyme-linked immunosorbent assay (ELISA) for Brucella abortus antibody was compared with direct agglutination, complement fixation and Coombs tests in studies of 112 sera. Of these, 15 gave positive results by ELISA tests which included the 13 sera that gave positive results in the other tests. The assay aided recognition of four groups: (i) sera with very high levels of specific IgG and significant levels of IgM and IgA from patients with acute brucellosis; (ii) sera with high levels of IgG only from patients with chronic brucellosis; (iii) sera with low levels of IgG only, representing residual antibody; (iv) sera with little or no brucella-specific antibody. ELISA was antibody-class specific, and the results were more readily interpreted than conventional seological data. Moreover, ELISA was more sensitive, more rapid and simpler than the battery of agglutination, Coombs and complement-fixation tests commonly used.

Antibodies, Bacterial↗
PubMedDate not supplied

Pyrolysis mass spectrometry characterisation and numerical taxonomy of Aeromonas spp.

Reference strains (2) and 29 isolates of Aeromonas spp. from clinical material and environmental specimens were characterised in traditional biochemical tests, and in pyrolysis mass spectrometry, which gives data reflecting whole-cell composition. Numerical taxonomic analyses of the data sets were compared with conventional identification at species level, and pathogenic potential, as inferred from the origin of the isolates. Clustering with conventional test reaction patterns showed, for each of the species represented, a clearly defined core group of 'typical' isolates, surrounded by a halo of aberrant strains. One further cluster comprised strains intermediate between A. caviae and A. hydrophila, and one strain was grossly atypical in both analyses. Clustering from pyrolysis data corresponded less well with species identification. Broadly, the biochemical division between core and halo strains was supported in pyrolysis for A. caviae and A. sobria, but the main group of A. hydrophila in pyrolysis comprised strains clustering in the core and halo groups of this species, and three strains intermediate between A. hydrophila and A. caviae in biochemical tests. Two further pyrolysis clusters comprised core and halo strains of A. hydrophila. However, pyrolysis clustering correlated well with inferred pathogenicity, showing four clusters of probable pathogens, six clusters of probable non-pathogens, and one two member cluster of doubtful status. Most strains that clustered in the species haloes, or in species-intermediate groups in biochemical tests, were non-human isolates, or were isolated in the absence of symptomatic infection. The correlation of inferred pathogenicity with biochemical clustering was poorer than that with pyrolysis clustering.

Aeromonas↗