Characterization of Enterococcus Bacteriophages From the Small Intestine of the Rat

Rogers, C. G.; Sarles, W. B.

doi:10.1128/jb.85.6.1378-1385.1963

Cited by 26 publications

(10 citation statements)

References 27 publications

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“…The only other known mechanism of natural gene exchange for enterococci is through infection with bacteriophages (35,173). Enterococcal bacteriophages have been isolated from stool (190) and have a narrow host range rendering them of potential use for strain typing (138). The ability of enterococcal bacteriophages to spread virulence traits or antibiotic resistance determinants is largely unknown.…”

Section: Enterococcal Genetic Exchangementioning

confidence: 99%

Virulence of enterococci

1994

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Enterococci are commensal organisms well suited to survival in intestinal and vaginal tracts and the oral cavity. However, as for most bacteria described as causing human disease, enterococci also possess properties that can be ascribed roles in pathogenesis. The natural ability of enterococci to readily acquire, accumulate, and share extrachromosomal elements encoding virulence traits or antibiotic resistance genes lends advantages to their survival under unusual environmental stresses and in part explains their increasing importance as nosocomial pathogens. This review discusses the current understanding of enterococcal virulence relating to (i) adherence to host tissues, (ii) invasion and abscess formation, (iii) factors potentially relevant to modulation of host inflammatory responses, and (iv) potentially toxic secreted products. Aggregation substance, surface carbohydrates, or fibronectin-binding moieties may facilitate adherence to host tissues. Enterococcus faecalis appears to have the capacity to translocate across intact intestinal mucosa in models of antibiotic-induced superinfection. Extracellular toxins such as cytolysin can induce tissue damage as shown in an endophthalmitis model, increase mortality in combination with aggregation substance in an endocarditis model, and cause systemic toxicity in a murine peritonitis model. Finally, lipoteichoic acid, superoxide production, or pheromones and corresponding peptide inhibitors each may modulate local inflammatory reactions.

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Section: Enterococcal Genetic Exchangementioning

confidence: 99%

Virulence of enterococci

1994

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“…The bacteriophages’ stability was examined in M17 broth supplemented with 20 m m CaCl 2 at pH values ranging from 3 to 10 after 24 h, while thermal resistance was assayed at 30, 40, 50 and 60°C for 1 h in M17 broth and determined according to the methods of Rogers and Sarles (1963). Sensitivity to CHCl 3 was determined by adding 0.5 mL of CHCl 3 to 10 mL of phage suspension, mixing vigorously and assaying the phages after 24 h at 4°C.…”

Section: Methodsmentioning

confidence: 99%

Characterization of four new Lactococcus lactis bacteriophages isolated from dahi whey

Masud

Latif

Hameed

2009

Int J of Dairy Tech

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Four lytic phages of Lactococcus lactis ssp. diacetylactis isolated from indigenous dahi whey were examined for their stability, growth characteristics and morphology. All these phages were partially inactivated by CHCl 3 , remained stable at 40°C and were partially inactivated at pH 3. There was a marked difference among these phages with respect to latent period, rise period and burst size. All phages belonged to Bradley's group B.

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“…It, therefore, belongs in morphological group B (1,9), as do most but not all streptococcal phages reported. Those in group B1 (1,6,9,10,25,39,50,54,66,68,73,76,85) may differ, in terminal tail structures, such as none, single filaments, knobs and single spikes, base plates, or base plates with multiple spikes. Some streptococcal phages with elongated heads, and thus in group e Calculated from Tm (see Materials and Methods).…”

Section: Studies During Competence Induction Inmentioning

confidence: 99%

Characterization of group H streptococcal temperate bacteriophage phi 227

Nugent¹,

Cole²

1977

J Virol

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¢227, a temperate phage from a group H streptococcus (Streptococcus sanguis), was propagated vegetatively in group H strain Wicky 4-EryR, and its characteristics were determined. A procedure dependent on multiplicity of infection, incubation time, and treatment of crude lysates with diatomaceous earth was found to optimize phage yield, resulting in titers of 1 x 1010 to 2 x 1010 PFU/ ml. Without prior treatment with diatomaceous earth, subsequent purification procedures (methanol, ammonium sulfate, polyethylene glycol) gave recoveries of less than 1% of crude lysate titers. Adsorption of k227 to host cells was relatively unaffected by the medium, but calcium (not substituted by magnesium) was required for formation of infectious centers. The phage receptor was present on purified cell walls, resisted trypsin and heat, and was removed by hydrochloric acid, trichloroacetic acid, and hot formamide: however, formamideextracted material failed to inactivate phage, and the nature of the receptor is unknown. Single-step growth experiments showed a latent period of 39 min and a burst size of 100 PFU/infectious center; results were unaffected by omission of supplemental Ca2+, by supplementation with Mg2, addition of glucose, or changes of pH between 6.35 and 8.0; but increased temperature (40 to 430C) shortened the latent period and decreased the burst size. The latent period was prolonged in genetically competent host cells and in chemically defined medium; and in the latter, the burst size was smaller. Phage replication was sensitive to those metabolic inhibitors which inhibited the host streptococcus: these included rifampin, fluorodeoxyuridine, hydroxyurea, dihydrostreptomycin, and 6-P-hydroxyphenylazouracil. The data suggest that 0227 does not code for a rifampinresistant RNA polymerase. However, in a rifampin-resistant host strain, phage replication and lysogen formation were both decreased, suggesting that altered host core polymerase had less affinity for (some) promoters on the k227 template. In transfection, a Ca2+-dependent stabilization step that was inhibited by Mg2+ was demonstrated; transformation was not affected by either Ca2+ or Mg2+, and the site and nature of the stabilization are unknown. More than one molecule of DNA was required for plaque formation. Biophysical characterization showed a type B phage of buoyant density (CsCl) 1.50, containing five proteins and 54.8% DNA. The duplex linear DNA had a molecular weight (calculated from contour length) of 23.2 x 106 and a guanine plus cytosine content (calculated from melting point) of 42.3 mol%. Similar characterizations of streptococcal phages, including biophysical data, have not been previously available. Streptococci designated as "group H" (17) in-(69), as well as naturally occurring lysogeny clude strains subject to DNA-mediated trans-(64), inhibit transformationa phenomenon formation (18, 20, 63, 65), and it is probable that also reported in Bacillus subtilis (70, 92, 93). this mode of genetic exchange can contribute to This inhibition in strepto...

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Characterization of Enterococcus Bacteriophages From the Small Intestine of the Rat

Abstract: ROGERS, C. G. (Univ-ersity of Wisconsin, Madison) AND W. B. SARLES. Characterization of enterococcus bacteriophages from the small intestinie of the rat.

Cited by 26 publications

References 27 publications

Virulence of enterococci

Virulence of enterococci

Characterization of four new Lactococcus lactis bacteriophages isolated from dahi whey

Characterization of group H streptococcal temperate bacteriophage phi 227

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