- Volume 29, Issue 1, 1989
Volume 29, Issue 1, 1989
- Articles
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Observations of the Ultrastructure of Infected Kidney Stones
More LessSummaryStruvite stones are formed as the result of urinary tract infection by urease-producing bacteria. Ultrastructural examination of calculi removed from a patient revealed bacteria incorporated throughout the stone matrix. Exopolysaccharide stained by ruthenium red was associated with most of the bacteria, but it represented only a small portion of the organic matrix in the stone. Localised deposits of calcium and phosphorus, components of carbonate-apatite, and magnesium, a struvite component, were detected in close proximity to the cells. Histochemical examinations revealed that several of the gram-negative bacteria within the stone matrix possessed high levels of urease activity. We propose that bacterial slime production, intimately involved in the initiation of stone matrix deposition, is less prominent in mature stones because of the increased incorporation of host-derived mucoproteins and mucopolysaccharides.
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The ability of mononuclear cells to coagulate blood in response to Coxiella burnetii
More LessSummaryEndocarditis is a rather frequent complication of Q fever caused by Coxiella burnetii. We examined the ability of phase I (virulent) or phase II (avirulent) C. burnetii to coagulate blood in the presence of human blood mononuclear cells in vitro. After incubation for 4 h, virulent phase I C. burnetii was an effective stimulant for mononuclear cells. Since this interaction is a potent trigger of blood coagulation through the extrinsic pathway, it could be responsible for the local deposition of fibrin on the surface of infected valves and the development of large vegetations in cases of endocarditis complicating Q fever.
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Bovine platelet aggregation by Fusobacterium necrophorum
M. Kanoe and M. YamanakaSummaryFusobacterium necrophorum aggregated bovine platelets. The aggregation was paralleled by the haemagglutinating ability of the organism. Treatment of the bacterial cells with antiserum to the homologous purified haemagglutinin reduced the degree of platelet aggregation. Scanning elcctronmicroscopy revealed that little lysis of the affected platelets occurred during the 1-h incubation period. Purified haemagglutinin became bound to the surfaces of the platelet cells as shown by immunofluorescence microscopy. These observations suggest that platelet aggregation is mediated by the haemagglutinin and may be related to the pathogenicity of the bacterium.
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Identification of viridans streptococci by pyrolysis-gas chromatography
More LessSummaryAn isothermal method of pyrolysis-gas chromatography (Py-GC) was used for the identification of viridans streptococci. Pyrograms from 104 reference strains were subjected to a discriminant analysis to produce classification coefficients for the identification of 74 test organisms. Five groups representing recognised species were discriminated but Streptococcus milleri strains could not be distinguished from S. sanguis. If S. milleri and S. sanguis are regarded as a single pyrogroup, only three strains out of 74 were incorrectly identified by Py-GC. A multidimensional scaling analysis of the Py-GC data produced a similar species grouping, but this statistical method was less satisfactory for pyrogram data than discriminant analysis. While Py-GC was moderately successful for the identification of viridans streptococci, this study indicated that the technique has limited use in diagnostic medical microbiology because it is time-consuming and lacks flexibility.
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Typing of Aeromonas species by protein fingerprinting: comparison of radiolabelling and silver staining for visualising proteins
More LessSummaryA method for typing Aeromonas species by silver staining of total soluble proteins separated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis is described. There was good agreement with the results obtained by autoradiography of whole-cell proteins for isolates examined by both methods.
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Identification of some antigenically related outermembrane proteins of strains of Vibrio cholerae O1 and non-O1 serovars involved in intestinal adhesion and the protective role of antibodies to them
More LessSummaryOuter-membrane proteins (OMPs) of Vibrio cholerae strains of O1 and non-O1 serovars were studied. Marked similarity was found in the OMP profiles of different V. cholerae O1 strains but the OMP profile of a non-O1 strain was somewhat different. Antigenic relatedness between the OMPs of different V. cholerae strains was established by enzyme-linked immunosorbent assay (ELISA). Immunoblotting experiments demonstrated that at least two OMPs of 36 and 25-26 Kda were immunogenic and common to strains of O1 and non-O1 serovars. Antiserum raised against the outer membrane of a V. cholerae strain, and rendered specific for its OMP by absorption with lipopolysaccharide, inhibited in vitro the intestinal adhesion of the homologous and heterologous strains of V. cholerae irrespective of their biotype, serotype and serovar. Furthermore, antiserum to OMPs induced passive protection against vibrio challenge in rabbit ileal loop experiments. These results suggest that the OMPs may be useful in immunoprophylaxis against cholera.
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Adaptive resistance to aminoglycoside antibiotics in Pseudomonas aeruginosa
More LessSummaryAminoglycoside-resistant variants of Pseudomonas aeruginosa strain PAO1 were readily selected by culturing the organism in medium containing increasing concentrations of gentamicin, tobramycin or amikacin until the strains were growing in a concentration of drug 128-fold greater than the minimal inhibitory concentration for the sensitive parent strain. These resistant strains exhibited characteristics previously associated with the impermeability type of resistance mechanism, i.e., they grew more slowly than the parent strain, the resistance was unstable in the absence of the antibiotic, and adaptation to one of the antibiotics conferred cross-resistance to other aminoglycosides. The adapted strains grew, with minimal morphological alterations, in concentrations of the various aminoglycosides that normally produced cell envelope damage, misshapen and filamentous cell formation, and cell lysis in the sensitive strain. Neither protein H1 nor phospholipid alterations appear to play a significant role in adaptive resistance to aminoglycoside antibiotics in this model system. The acquisition of adaptive resistance to the aminoglycoside antibiotics did not confer resistance to polymyxin B, another cationic antibiotic which is thought to share binding sites within the outer membrane with the aminoglycosides.
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Candida species and C. albicans biotypes in women attending clinics in genitourinary medicine
More LessSummaryYeasts were isolated from two or more anatomical sites in 198 women attending genitourinary clinics on at least two occasions. The yeast biotypes isolated concurrently from the vagina and urethra were the same in 138 (99%) of 140 instances, and 94% of 124 concurrent genital and anal isolates were of matching types, whereas only 75% of concurrent genital and oral isolates were of the same type. Mixtures of Candida spp. or C. albicans biotypes were encountered only five times among 545 yeast-positive samples. In instances where Candida spp. were isolated at successive times from the same site in a patient, the same yeast type was encountered on 97 (87%) of 112 occasions when the interval between samples was less than 15 weeks, and on 19 (66%) of 29 occasions when the interval was 15 weeks or more. These data indicate a tendency to carriage of phenotypically consistent types of Candida among most women attending genitourinary clinics.
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Use of the mouse for the isolation and investigation of stomach-associated, spiral-helical shaped bacteria from man and other animals
More LessSummarySpiral-helical shaped bacteria other than Campylobacter pylori have been shown to infect the human stomach. The characteristic helical morphology of these bacteria appears to be similar to that of bacteria found in the stomachs of many other animal species. Early reports on gastric bacteria suggested that rodents may be useful for investigation and isolation of stomach-associated bacteria. Therefore, anaesthetised mice were given, through a stomach tube, a heavy suspension of a spiral-helical bacterium from a cat, scrapings of gastric mucus from primates, or a homogenised whole-antral biopsy from a human patient. At intervals after inoculation, gastric biopsies were examined by lightmicroscopy and electronmicroscopy for the presence of spiral-helical bacteria. Significant colonisation was observed in 40% of mice 1 week, and in 80% of mice 11 weeks, after inoculation with suspensions of the cat isolate. Mice were also successfully colonised by spiral bacteria present in homogenised human biopsy material and by other spiral bacteria from a monkey. These observations suggest that mice may prove to be useful animals for the study of gastric bacteria that are, as yet, non-cultivable and for analysis of some of the attributes commonly thought to be involved in colonisation.
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A Comparison of Bacteroides ureolyticus isolates from different clinical sources
More LessSummaryClinical 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.
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