- Volume 16, Issue 3, 1983
Volume 16, Issue 3, 1983
- Short Articles
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Gain of ornithine decarboxylase activity by a strain of Shigella flexneri serotype 6 on the introduction of an R plasmid
More LessSUMMARYThe introduction of R plasmid S-a into a strain of Shigella flexneri serotype 6 resulted in the strain gaining the ability to decarboxylate ornithine. The possible reasons for the phenomenon are discussed and the result is compared with that obtained previously when the introduction of R plasmids into a different strain of the same species resulted in enhanced gas production from a range of carbohydrates.
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- Articles
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Interaction between Yersinia pseudotuberculosis and the HeLa cell surface
More LessSUMMARYThe adherence of Yersinia pseudotuberculosis to the surface of HeLa cells at 4°C was studied. This temperature allows adhesion of bacteria but prevents engulfment. Adhesion between the bacteria and the cells was not dependent upon the presence of serum, Ca2+ or Mg2+ in the medium. Maximum adhesion was obtained at pH 6.5–7.9 and pretreatment of the cells with formaldehyde or glutaraldehyde inhibited the attachment of the bacteria. The interaction between the bacteria and the cell surface seems to involve cellular processes that are mostly microvilli. An intimate association between the bacteria and the cellular glycocalyx was found. Three virulent bacterial strains adhered more easily to the cell surface than five avirulent strains. Maximum adherence was obtained with bacteria from late logarithmic and early stationary phases of growth. The bacteria gradually lose their adhesive property when cultivated for several generations at 37°C in nutrient broth but not when cultivated at 20°C. Treatment of the bacteria with protease IV from Streptomyces caespitosus markedly reduced the efficiency of attachment.
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Streptococci isolated from the bloodstream and gingival crevice of man
More LessSUMMARYOne hundred and twenty six strains of streptococci isolated from the bloodstreams of 123 hospital in-patients—55 with endocarditis—and 255 strains isolated from the gingival crevices of 66 volunteers were characterised. Species isolated were Streptococcus mitior, S. sanguis, undifferentiated viridans streptococci, S. salivarius, S. milleri, S. mutans, S. bovis and S. faecalis. There was no significant difference between the distribution of species in blood and in the gingival crevice. S. mitior and S. sanguis were found less frequently in blood than their presence in the gingival crevice would have suggested, whereas S. milleri was found more frequently. This may indicate that S. milleri is more invasive or that it enters the bloodstream from sources other than the gingival crevice.
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Resistance of propionibacteria to antibiotics used in the treatment of acne
More LessSUMMARYStrains of propionibacteria resistant to clindamycin or clindamycin and erythromycin were isolated from four patients with acne, three of whom were receiving clindamycin. Four strains of P. acnes and one of P. granulosum with moderate levels of tetracycline resistance were isolated from 25 patients with acne being treated with tetracycline. A similar increase in tetracycline resistance was achieved by training sensitive strains in vitro. P. acnes was sensitive to sulphonamide and trimethoprim but some strains of P. granulosum were resistant to sulphonamide. Similar reports of clindamycin and erythromycin resistance from the USA suggest resistance may be increasing in isolates from patients with acne.
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Effect of serum concentration and metabolic inhibitors on the attachment of Treponema Pallidum to rabbit cells
More LessSUMMARYThe effect of host-cell metabolism on the attachment of Treponema pallidum to mammalian cells in vitro was studied. The growth of baby rabbit genital organ (BRGO) cells was enhanced by increasing the concentration of serum (“serum shift-up”) in the growth medium. Cells starved for 24 h in serum-free medium showed a burst of DNA synthesis when shifted to fresh medium containing 20% serum. In aerobic conditions, they were much more heavily coated with attached T. pallidum than cells shifted to 20% serum after maintenance at serum concentrations of 2.5%, 5% or 10%. This effect was very pronounced during the first few hours of co-incubation. In microaero-philic conditions, the extent of T. pallidum adherence also paralleled the increase in DNA synthesis by BRGO cells. Cycloheximide and methotrexate greatly inhibited DNA and protein synthesis in BRGO cells, but did not affect the motility of T. pallidum. When BRGO cell metabolism was inhibited by these two drugs, attachment of T. pallidum was significantly decreased. These results indicate that T. pallidum attaches best to actively growing BRGO cells in tissue culture. This may explain the apparently preferential parasitism of actively growing tissues by T. pallidum in syphilis in man.
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Auxotyping of Neisseria gonorrhoeae isolated in the United Kingdom
More LessSUMMARYOne hundred and twenty consecutive isolates of Neisseria gonorrhoeae from the County of Avon, UK, were examined by auxotyping and penicillin susceptibility testing. Requirements for proline (Pro), arginine (Arg), hypoxanthine (Hyp), uracil (Ura) and methionine (Met) were determined with a modified Heckels’ medium. Prototrophic strains accounted for 29.9% of isolates and were a heterogeneous group as judged by penicillin susceptibility testing. The group most generally susceptible to penicillin required Arg-Hyp-Ura, and represented 27.5% of isolates. The Pro-Arg°-Ura auxogroup (10% of isolates) had the narrowest range of penicillin susceptibility. Prototrophic strains had a reduced growth rate on arginine-free medium. Investigations of this phenomenon and suitable methods for auxotyping are reported.
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Virological course of herpes zoster in otherwise normal hosts
More LessSUMMARYThe virological course of herpes zoster infection in 42 otherwise normal hosts was studied by virus isolation and antibody titration. Varicella-zoster virus (VZV) was isolated from vesicle fluid from all three patients examined on the first day of the vesicular eruption and from five out of six examined on the second day. The isolation rate fell to one out of six patients on the seventh day of illness and VZV was not isolated from patients at a later stage of the illness. IgG antibodies were detected by IFAMA and ELISA, in sera from all the patients by the end of the first week of illness; IgG antibody titres were highest during the second and the third weeks. IgM antibodies to VZV were detected in sera from six of the 42 patients with herpes zoster after fractionation by ion-exchange chromatography.
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Effect of low intraphagolysosomal pH on antimicrobial activity of antibiotics against ingested staphylococci
C. Lam and G. E. MathisonSUMMARYThe ability of aminoglycoside antibiotics and rifampicin to kill Staphylococcus aureus that had been ingested by blood polymorphonuclear leukocytes (PMNs) in vitro was investigated. Gentamicin and streptomycin failed to kill intracellular staphylococci, possibly because they could not penetrate PMNs or were inactivated by the low intraphagolysosomal pH. Rifampicin accumulated within the leukocytes in a form that killed staphylococci in a cell-free medium, but the bactericidal activity of intracellular rifampicin against ingested staphylococci was much less than that in a cell-free system. Investigations with granules isolated from PMNs, at various pH-values, revealed that the impairment of rifampicin activity was a result of limitation of the staphylococcal growth rate by a low pH. These observations indicate that the inhibition of intraphagocytic bacterial growth by the low intraphagolysosomal pH and other phagolysosomal bacteristatic factors determines the antimicrobial activity of accumulated antibiotics.
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Proteus morgani is less frequently associated with urinary tract infections than Proteus mirabilis—an explanation
More LessSUMMARYThe metabolic activities of faecal and urinary strains of Proteus morgani and P. mirabilis were compared. Regardless of origin, the generation time of P. morgani strains in urine was approximately twice as long as that of the P. mirabilis strains. Urease synthesis was constitutive in P. morgani strains but required induction with urea in the P. mirabilis strains. In the presence of urea, the P. mirabilis strains liberated ammonia more rapidly and produced alkaline conditions more quickly than P. morgani strains, although they synthesized much less urease. These characteristics may place P. morgani strains at a disadvantage in comparison with P. mirabilis strains in their ability to cause urinary tract infections.
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The purification, structure and synthesis of proticine 3
More LessSUMMARYThe ability of Proteus mirabilis to produce the bacteriocin, proticine 3, is found almost exclusively in strains that cause severe infections of the upper urinary tract. Proticine 3 was purified from lysates of mitomycin C-induced cultures. Biological activity was associated with structures resembling bacteriophage tails which, when first produced, were in the form of “nails” with one pointed end and a base plate with appendages at the other end. This form was unstable and changed to a “rocket” form in which the outer sheath contracted and thickened to reveal a protruding, hollow core that often became detached from the sheath. Purified proticine 3 comprises two major and nine minor proteins. Fluorography showed that during production of the proticine, a 58 000 mol. wt protein was synthesized late in the induction process and became the most intensely labelled protein in the culture. Synthesis of this protein coincided with the appearance and increase in titre of biologically-active proticine within the cell and with the appearance of “nail” forms. The protein is believed to be shed when an active “nail” is converted to an inactive “rocket” and to be either the component of proticine 3 associated with its lethal activity, or the protein required for the correct assembly of the constituent components into a biologically-active particle. The role of proticine 3 as a virulence factor is discussed.
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Role of DNA and bacteriophage in campylobacter auto-agglutination
More LessSUMMARYAuto-agglutinated and non-agglutinated cells of Campylobacter jejuni and C. coli were examined by transmission electronmicros-copy in phosphotungstate negative stain. Agglutination was induced by three factors (1) extracellular DNA, (2) an aggregated protein, probably a bacteriophage precursor, and (3) free phage-tail sheaths. Auto-agglutinated cells were often “leaky,” with a mantle of adhering DNA. About 80% of the auto-agglutinated cells could be resuspended after treatment with DNAase. Flagella were loosely embedded in protein aggregates, especially in phage-infected cultures. They were clumped in a side-by-side arrangement by free phage-tail sheaths. These findings suggest that auto-agglutination could be minimised in suspensions of organisms intended for use in agglutination tests by harvesting early logarithmic-phase cells containing no more than a low phage population. The most common C. jejuni phage had a contractile tail, a head diameter of 60-70 nm, and an overall length of 180-210 nm. A phage isolated from C. jejuni strain 1590 was morphologically identical with C. coli phage.
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Effect of four antibiotics on haemolysin production and adherence to human uroepithelial cells by Escherichia coli
More LessSUMMARYThe effect of subinhibitory concentrations of chloramphenicol, gentamicin, netilmicin and streptomycin in artificial culture media on growth, haemolysin production and adherence to uroepithe-lial cells by Escherichia coli was examined. Only streptomycin inhibited haemolysin production without inhibiting growth of the bacteria. In contrast, the inhibition of haemolysin production by chloramphenicol, gentamicin or netilmicin was directly proportional to the degree of inhibition of growth. Bacterial adherence to human uroepithelial cells, measured microscopically, was affected by all four antibiotics but to different extents. There was no correlation between inhibition of haemolysin biosynthesis and the ability of the bacteria to adhere to uroepithelial cells after growth in the presence of the antibiotics.
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The response of Pseudomonas aeruginosa to azlocillin, ticarcillin and cefsulodin
More LessSUMMARYThe morphological response of Pseudomonas aeruginosa to azlocillin, ticarcillin and cefsulodin was investigated by electron microscopy. Each antibiotic initially caused the formation of filaments. On further incubation in the presence of azlocillin, deposits of dense intracellular material were observed; these were absent from cells exposed to the other two antibiotics. On continued incubation, lysis of the filaments occurred, but the mode of lysis differed between the antibiotics: azlocillin caused breakage at a restricted number of sites in the cell wall, ticarcillin produced breakage at many points and cefsulodin caused extensive cell-wall damage. In addition, ticarcillin and cefsulodin appeared to cause more lysis and spheroplast formation than did azlocillin.
The morphological changes correlated with turbidimetric measurements of bacterial response to the three antibiotics, which showed ticarcillin and cefsulodin to act more rapidly than azlocillin.
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The role of iron deficiency in experimentally-induced oral candidosis in the rat
More LessSUMMARYIn comparison with normal rats, those with iron deficiency anaemia showed no significant difference in susceptibility to experimental infection with Candida albicans although anaemic rats had a significantly greater incidence of persistent infection. These findings support the suggestion that patients with chronic candidosis should be investigated for iron deficiency.
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Haemagglutinins and adhesion of Salmonella typhimurium to HEp2 and HeLa cells
More LessSUMMARYWhen fimbriate (Fim +) strains of Salmonella typhimurium were grown in static broth, many bacteria were in the fimbriate phase and bore fimbrial mannose-sensitive haemagglutinin (MSHA) that enabled them to adhere to guinea-pig and other erythrocytes and to agglutinate them in rocked tile and static settling tests. When either Fim+ or Fim-strains were grown on phosphate-buffered nutrient agar, the bacteria formed a diffusible, mannose-resistant haemagglutinin (MRHA) that gave dispersed sediments with sheep and pig erythrocytes in static settling tests, but without evidence of bacterial adhesion to the erythrocytes. On exposure, from above or from below, to cultured HEp2 and HeLa cells for 30 or 90 min at 37°C, motile MSHA-rich, MRHA-negative broth-grown bacteria adhered to the cells in large numbers (e.g., 20-100/cell), but motile MSHA-negative, MRHA-negative broth-grown bacteria and non-motile MSHA-negative, MRHA-rich agar-grown bacteria adhered in only small numbers (usually < 1/cell). Thus, strong adhesiveness of bacteria for cultured cells in vitro appears to depend upon the presence of MSHA, not MRHA, and as Fim-(MSHA-negative) strains of S. typhimurium are known to be highly infective in animals, a strong reaction in the in-vitro model does not reflect a property of the bacteria essential for infectivity in vivo.
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- Books Received
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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 66 (2017)
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Volume 65 (2016)
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Volume 64 (2015)
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Volume 63 (2014)
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Volume 62 (2013)
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Volume 61 (2012)
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Volume 60 (2011)
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Volume 59 (2010)
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Volume 58 (2009)
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Volume 57 (2008)
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Volume 56 (2007)
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Volume 55 (2006)
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Volume 54 (2005)
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Volume 53 (2004)
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Volume 52 (2003)
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Volume 51 (2002)
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Volume 50 (2001)
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Volume 49 (2000)
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Volume 48 (1999)
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Volume 47 (1998)
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Volume 46 (1997)
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Volume 45 (1996)
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Volume 44 (1996)
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Volume 43 (1995)
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Volume 42 (1995)
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Volume 41 (1994)
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Volume 40 (1994)
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Volume 39 (1993)
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Volume 38 (1993)
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Volume 37 (1992)
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Volume 36 (1992)
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Volume 35 (1991)
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Volume 34 (1991)
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Volume 33 (1990)
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Volume 32 (1990)
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Volume 31 (1990)
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Volume 30 (1989)
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Volume 29 (1989)
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Volume 28 (1989)
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Volume 27 (1988)
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Volume 26 (1988)
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Volume 25 (1988)
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Volume 24 (1987)
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Volume 23 (1987)
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Volume 22 (1986)
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Volume 21 (1986)
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Volume 20 (1985)
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Volume 19 (1985)
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Volume 18 (1984)
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Volume 17 (1984)
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Volume 16 (1983)
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Volume 15 (1982)
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Volume 14 (1981)
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Volume 13 (1980)
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Volume 12 (1979)
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Volume 11 (1978)
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Volume 10 (1977)
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Volume 9 (1976)
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Volume 8 (1975)
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Volume 7 (1974)
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Volume 6 (1973)
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Volume 5 (1972)
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Volume 4 (1971)
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Volume 3 (1970)
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Volume 2 (1969)
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Volume 1 (1968)