- Volume 5, Issue 4, 1972
Volume 5, Issue 4, 1972
- Articles
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A Study Of Metabolic Factors Involved In The Intracellular Germination Of Clostridium Botulinum Spores After Phagocytosis
J. B. Suzuki and N. GreczSUMMARYThe environment within the metabolically active polymorphonuclear leucocyte during phagocytosis is conducive to the germination of phagocytically ingested spores of Clostridium botulinum type A. Specific metabolic inhibitors of leucocyte function—glyceraldehyde, hydrocortisone, colchicine, methimazole and azide—were used to study metabolic pathways during phagocytosis that may be responsible for inducing spore germination within the leucocyte.
Leakage of 45Ca from labelled Cl. botulinum spores was taken as evidence of spore germination. Release of free 45Ca from phagocytosed spores in sporeleucocyte mixtures in in-vitro systems was normal in the presence of hydrocortisone, methimazole, azide and methimazole+azide. These findings indicate that H2O2 production, iodination and myeloperoxidase activities during phagocytosis are not required for germination. In the presence of glyceraldehyde or colchicine, release of 45Ca from spore-leucocyte mixtures was profoundly inhibited and this indicates that glycolysis and lysosome degranulation are essential for intraleucocytic spore germination.
In leucocytes from patients with a genetic abnormality of phagocytosis, i.e., chronic granulomatous disease of childhood (CGD), germination of spores was significantly depressed. Since normal mechanisms of H2O2 production and possibly of lysosomal degranulation are blocked in CGD leucocytes, the results suggest that H2O2 and lysosomal enzymes are involved in triggering spore germination in this model. Nevertheless, a limited release of 45Ca was observed and this seems to indicate that small amounts of lysosomal enzymes are available for reaction with engulfed spores in CGD leucocytes.
The results of these studies with metabolic inhibitors and genetic blocks lead to the view that germination of spores of Cl. botulinum within leucocytes is triggered by the combined action of lowered pH resulting from glycolysis together with lytic enzymes resulting from degranulation of lysosomes.
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The Isolation Of Red Yeast-Like Fungi In A Diagnostic Laboratory
More LessSUMMARYA recently published scheme of investigation was used to identify all isolates of red yeast-like fungi from clinical specimens over a 29-mth period. In 8062 specimens we found 45 strains of Rhodotorula rubra, seven of R. minuta var. texensis, three of R. aurantiaca, one of R. glutinis var. glutinis, one of R. pilimanae and one of Sporobolomyces salmonicolor. The commonest single source of these fungi was stool, of which 2.6 per cent. of specimens yielded Rhodotorula spp. None of the strains isolated appeared to be the cause of an infection. The routine identification of red yeast-like fungi could be made without difficulty, and techniques employed are recommended to other hospital laboratories wishing to provide this service.
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In-Vitro Studies On The Bactericidal Properties Of Natural And Synthetic Gastric Juices
More LessSUMMARYArtificial gastric juice was prepared and shown to be comparable with natural gastric juice in its bactericidal activity against a stock strain of Shigella sonnei. The acid component of natural gastric juice was the major bactericidal component, but pepsin increased the bactericidal effect significantly. Other components such as lysozyme and amino acids contributed to the lethal properties of the artificial system, whereas sugars and organic acids collectively exerted a protective influence. Peptone or starch added to the gastric juice reduced its bactericidal activity. The artificial gastric juice was most effective in killing Shigella sonnei in tests at pH 1.5-pH 3.0; at values above pH 3 the organism was able to survive in this system.
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The Pathology And Immunology Of Bordetella Pertussis Infection
More LessSUMMARYStrains of Bordetella pertussis, Bord. parapertussis and Bord. bronchiseptica adhered readily to live cultures of human fibroblasts. Sera from animals immunised against Bord. pertussis contain antibodies that specifically prevent the adhesion of Bord. pertussis to the cells. Anti-adhesion antibodies will not detach Bord. pertussis already adherent to fibroblasts. Limited experiments suggest that the same conclusions are true for Bord. pertussis and monkey tracheal epithelium. It is concluded that the adhesion of Bord. pertussis to cells depends on a biochemical mechanism, and is analogous to the adsorption of influenza virus on red cells.
Titres of anti-adhesion antibody in blood and saliva show little correlation, and it seems probable that there are two immunity systems in whooping cough: (a) a true prophylactic immunity in which locally produced IgA secretory immunoglobulin prevents the adhesion of the organism to the mucous membrane; and (b) a therapeutic system, involving polymorphs and an opsonin, which after the development of inflammation acts at the surface of the membrane and eliminates the infection.
The current practice of parenteral vaccination would seem to induce the latter type of immunity, the infection itself the former type.
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Physiological Properties Of Mutagen-Induced Variants Of Candida Albicans Resistant To Polyene Antibiotics
More LessSUMMARYMutants resistant to nystatin have been selected from cultures of a strain of Candida albicans isolated from a patient after it had been treated with N-methyl-N'-nitro-N-nitrosoguanidine. The resistance of the mutants to nystatin, amphotericin B and filipin was respectively 12- to 16-fold, 30- to 40-fold and 3- to 7-fold, more than that of the parent strain. Sensitivity to three non-polyene compounds, clotrimazole, 5-fiuorocytosine and pyrrolnitrin, was not altered. The mutants were identifiable as C. albicans by standard laboratory tests; two of them seemed to have a decreased ability to form mycelium. There was some loss of acquired resistance after 46 passages in vitro. The mutants had more homogeneous patterns of resistance than did a resistant isolate of the same parent strain which had been serially subcultured in the presence of increasing concentrations of nystatin. Mutant cells were found to be of greater eccentricity, and of greater total volume and mass, than those of the parent strain. In shaken culture at 37°C the mutants grew more slowly than the parent; decreased growth rates and prolonged lag phases were also noted for the mutants when grown on solid media at four temperatures. The resistant isolates were agglutinated by similar dilutions of an antiserum to C. albicans, and the agglutinins were removed by absorption of the antiserum with the parent strain. Possible taxonomic differences arising from loss of mycelium-forming ability of C. albicans strains are discussed.
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Studies On Staphylokinase
More LessSUMMARYStaphylokinase in the supernatant of cultures of Staphylococcus aureus was concentrated and then purified twice successively by isoelectric focusing. The total activity of staphylokinase was increased about 100 per cent. after the first isoelectric focusing. The cause of this was investigated. It was also shown by means of this separation technique that staphylokinase is a heterogenous protein, with isoelectric points at pH 5.8 (component A), 6.2 (component B) and 6.8 (component C). The degree of purification was calculated.
Some properties of the components were studied. The effects of the following metal ions: Ca++, Mg++, Mn++, Cu++, Pb++, Zn++, Ag+ and Co++; and of EDTA and cysteine, were examined. No significant differences in these respects between the three components were observed. The pH for optimal activity also seemed to be the same for the main components.
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The Effect On Virulence Of Transferring R Factors To Salmonella Typhimurium In Vivo
More LessSUMMARYDifferent R factors were transferred from R+ Escherichia coli to two strains of Salmonella typhimurium in the alimentary tractof chicks. The virulence of the R+ S. typhimurium strains was then compared with the R- strains from which they were derived by giving them orally to groups of 1-day-old chicks.
The mortality rates from infection with the R+ strains were similar to, slightly lower than, or much lower than those from infection with the corresponding R- strains.
Virulence tests on S. typhimurium strains from which R factors had been eliminated, and on strains to which R factors had been transferred at a high rate in vitro, suggested that the very possession of R factors was responsible for the smaller reductions in mortality rate observed with some of the R+ strains; but the other strains with which greatly reduced mortality rates were observed may have been low-virulence variants of the R- parent strain that had subsequently acquired R factors from the R+ E. coli.
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The Prevention Of Experimental Clostridium Novyi Gas Gangrene In High-VelociTy Missile Wounds By Passive Immunisation
More LessSUMMARYSheep that were wounded in the thigh muscle by a high-velocity bullet and simultaneously infected there with spores of Clostridium novyi type A were used to evaluate the prophylactic effectiveness of gas-gangrene antitoxin. Control sheep that had not received antitoxin almost all died of gas gangrene within 48 hr after wounding (survival rate 4.6-13 per cent. within 90 per cent. confidence limits). The survival rate increased when antitoxin was given prophylactically.
The effectiveness of antitoxin in preventing gas gangrene was found to depend to a large extent on the interval of time between the challenge and administration of antitoxin. If this was 9 hr or less, antitoxin was almost completely effective (survival rate 94-98.5 per cent.). The survival rate decreased as the interval lengthened; when it was 18-21 hr or more, the rate was similar to that observed with challenged controls.
It is concluded that gas-gangrene antitoxin is likely to be of value in the prevention of post-traumatic gas gangrene caused by CI. novyi, provided that it is given as soon as possible and preferably within 9 hr after wounding.
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The Prevention Of Experimental Clostridium Novyi And Cl. Perfringens Gas Gangrene In High-Velocity Missile Wounds By Active Immunisation
More LessSUMMARYSheep were immunised with a mixed vaccine containing the toxoids of Clostridium perfringens, Cl. septicum and Cl. novyi and challenged at different intervals after immunisation. The sheep were wounded and challenged in the thigh muscle by a high-velocity bullet that passed through a piece of battledress impregnated with a suspension of either Cl. novyi spores or Cl. perfringens culture.
Immunisation was almost completely effective in preventing the onset of gas gangrene due to Cl. novyi even 1 yrafter immunisation, the survival rate being 82.5-94.5 percent, within 90 per cent, confidence limits (rate for unvaccinated controls: 2·5-8·5 per cent.). Vaccinated sheep that survived challenge with Cl. novyi werelater challenged with Cl. perfringens and survived this, the rate of survival being 83-94.5 per cent, (rate for unvaccinated controls : 12-50 per cent.). The role that such a vaccine might play in the prevention of gas gangrene in man is discussed.
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Spread Of Pseudomonas Aeruginosa In A Burns Unit
More LessSUMMARYAn epidemiological investigation of the spread of Pseudomonas aeruginosa in a burns unit was conducted by means of a phage-typing technique. During the period of treatment 62 per cent. of the patients were colonised with P. aeruginosa in their burns. The frequency of colonisation was correlated to the extent and depth of the burns. Thirty-three per cent. of the isolates of P. aeruginosa belonged to the same phage type, 1214/109/F8.
Endogenous infection from intestinal flora to burn in the same patient was not commonly observed. In several cases P. aeruginosa was present for a long period of time in the ward environment without colonising patients being treated for open, extensive and recent burns. The reason for this is discussed. No predominant route of infection could be demonstrated.
It was not possible permanently to decontaminate the environment by disinfection of wash-basins and sinks.
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Examination By Electron Microscopy Of The Interaction Between Peritoneal Phagocytes And Corynebacterium Ovis
More LessSUMMARYThe host-parasite interactions between (i) macrophagesand polymorphonuclear neutrophil leucocytes (PMN) of normal and immune mice, rabbits and guinea-pigs, and (ii) thefacultative intracellular parasite, Corynebacterium ovis, were examined with the electron-microscope. Normal mouse cells were incapable of exerting a significant bactericidal effect and quickly succumbed to the necrotising action of the organism. Macrophages from immune mice were individually no more effective in killing C. ovis, but the organisms disappeared from the peritoneal cavities more rapidly in immune than in normal mice. Bacterial clearance appeared to be associated with the reingestion by scavenging macrophages of viable C. ovis within degenerating phagocytes. Suspending C. ovis cells in hyperimmune sheep serum rendered them susceptible to bacteriolysis by normal or immune mouse cells. Rabbit PMN exerted an extremely rapid destructive action on the organism; rabbit macrophages and guinea-pig PMN and macrophages also destroyed C. ovis but less effectively. In studies with all three animal species, viable organisms were found within phagolysosomes which were characterised by a relatively narrow peribacillary space and crenate limiting membrane. An electron-lucent zone always surrounded viable bacteria, and this was assumed to indicate the intact state of the surface lipid layer which was of similar density to the contiguous host enzymic material. Bacteria undergoing degeneration were often found within vacuoles with a wide peribacillary space and smooth limiting membrane; the surface lipid zone was wholly or partly obliterated in these organisms. It appears that C. ovis surface lipid may function as a barrier against the degradative enzymes of mouse phagocytes.
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Prevention Of Swarming Of Clostridium Septicum
More LessSUMMARYA CI. septicum O antiserum, prepared in the rabbit against the two serological groups of Moussa, inhibits the swarming growth of CI. septicum in plate cultures. Advantage may be taken of thisin the separation of other organisms from mixtures with CI. septicum and in performing surface viable counts with CI. septicum.
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Genetic Control In Methicillin-Resistant Strains Of Staphylococcus Aureus
More LessSUMMARYSix methicillin-resistant strains of Staphylococcus aureus isolated in Britain were examined for loss of resistance after storage for 30 mth at room temperature. Resistance to methicillin was lost from five out of six, to tetracycline from four out of six, to erythromycin from two out of four, and penicillinase from all five that were producers of it. The methicillin-sensitive segregants resembled the wild strains in bacteriophage-typing pattern, haemolysin production, Tween 80 reaction, pigmentation, and resistance to lysostaphin and to other antibiotics.
Methicillin resistance was transduced from lysates of three of the strains. Although the effect of ultraviolet light was characteristic for a plasmid gene in strain no. 11164, transduction occurred at low frequency (10−9 – 10−10) from this and from the other strains, and to a narrow range of recipients. Methicillin resistance was not transferred to recipients in mixed culture.
In contrast, plasmid genes determining lactamase production, or resistance to tetracycline or erythromycin, were transduced from lysates and transferred in mixed cultures from these strains at frequencies from 10−5 – 10−8. These results may account for the confinement of methicillin resistance to few types of staphylococci whilst other resistance genes have become much more widespread.
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The Effect Of The Medium And Source Of Growth Factors On The Satellitism Test For Haemo-Philus Species
More LessSUMMARYThree types of nutrient agar were examined for their suitability in determining the X and V requirements of Haemophilus influenzae and H. parainfluenzae. The 80 strains tested were either from type culture collections or freshly isolated. Twenty-six strains required V factor only and 54 both X and V factors when proteose peptone agar was employed with blood asa source of X. On a nutrient agar prepared from Oxoid Nutrient Broth no. 2, when haemin was used as the source ofXfactor the distribution was almost exactly reversed; 51strains appeared to be V-dependent and only 27 X- and V-dependent. When tests were carried out on proteose peptoneagar with added sodium oleate and thiamin (a medium providing essential growth requirements for Haemophilus with the exception of X and V factors), 43 strains were X and V dependent and 37 dependent on V only.The use of this last medium for satellitism tests is suggested.
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Photodynamic Inactivation Of Rubella Virus
J. C. Booth and H. SternSUMMARYRubella virus possesses inherent photosensitivity and slowly loses infectivity when exposed to light. Sensitisation with proflavine markedly increases the rate of photoinactivation, and loss of infectivity, without loss of haemagglutinin activity, is most readily achieved at pH 9.0. Photodynamically inactivated rubella virus stimulates HI antibody formation in monkeys.
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Linked Extrachromosomal Resistance To Streptomycin And Kanamycin In Staphylococcus Aureus
More LessSUMMARYTwo strains of Staphylococcus aureus that have linked and unstable resistance to kanamycin andstreptomycin have been isolated. It was shown that in oneof these strains (1) resistance to kanamycin and streptomycin was co-ordinately lost at highfrequency during nineserial screenings of resistant variants, (2) resistance toboth antibiotics could beco-transduced, and (3) in the transductants, resistance to these antibiotics was both linked and unstable,as in the donor strain. In both strains resistance tostreptomycin and kanamycin appears to be controlled by the same extrachromosomal element.
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Isolation Of Salmonella From Sewage By Anaerobic Methods
More LessSUMMARYSalmonellae present in or artificially inoculated into sewage were readily isolated by plating selenite F enrichment cultures on deoxycholate citrate agar provided the plates were incubated anaerobically in the presence of about 10 per cent. (v/v) carbon dioxide. Under these conditions, salmonellae gave distinctive jet-black colonies, pseudomonads were suppressed and the growth of Proteus was markedly inhibited. A modified procedure was required for satisfactory recovery of Salmonella typhi, notably the use of double-strength selenite medium and the omission of lactose from the deoxycholate citrate agar.
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Volumes and issues
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Volume 73 (2024)
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Volume 72 (2023 - 2024)
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Volume 71 (2022)
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Volume 70 (2021)
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Volume 69 (2020)
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Volume 68 (2019)
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Volume 67 (2018)
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Volume 65 (2016)
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Volume 64 (2015)
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