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At least 19 recordsLinked to original sources
PubMed1975

Pyocin-sensitivity testing as a method of typing Pseudomonas aeruginosa: use of "phage-free" preparations of pyocin.

A method for pyocin-sensitivity typing by means of "phage-free" preparations of pyocin is described. The method was tested on 227 isolates of P. aeruginosa, collected from 34 different foci of infection in hospitals in the British Isles and the results were compared with those for combined serological and phage typing of all strains and pyocin production of 105 of the isolates. It is concluded that pyocin-sensitivity typing is a simple and reliable method giving a high degree of discrimination, comparable to that of combined serological and phage typing, and it is suitable for use in routine hospital laboratories.

Bacteriocins↗
PubMed1991

Pyocin typing of Pseudomonas aeruginosa isolates from children with cystic fibrosis.

Pyocin typing and serotyping of 433 strains of Pseudomonas aeruginosa from children with cystic fibrosis (CF) showed that pyocin type 9 was predominant, particularly in association with polyagglutinating serotype. The common pyocin groups, 1, 5 and 10, made up only 20% of these isolates in contrast to reported rates of up to 89% in other studies using non-CF strains. No strains of pyocin type 3 were found. Polyagglutinating strains made up 72% of strains from patients colonized with P. aeruginosa for more than 12 mths. Pyocin type 9 was associated with 93% of polyagglutinating strains. The parallel between pyocin type 9 and polyagglutinating serotype suggests that these may both be characteristics acquired by P. aeruginosa colonizing patients with CF. Because of confounding between duration of colonization and exposure to cross-infection, this study does not allow definition of the role of cross-infection in determining the characteristics of these strains in most patients. In siblings, however, evidence supports a role for cross-infection either between siblings or from a common source. In 6 pairs of siblings studied, each pair had at least 1 pyocin group in common concurrently, either at entry to the study or after an interval of several months. Identical and unusual pyocin groups were recognized in samples obtained on the same day from pairs of siblings. More studies are needed to compare results of pyocin typing with methods such as genome fingerprinting to characterize these strains and determine whether the observed distribution of pyocin groups in CF isolates is related to cross-infection or whether the combination of pyocin type 9 with polyagglutinating serotype is a characteristic of CF strains.

Adolescent↗
PubMed1975

Preferential inhibition of lipid synthesis by the bacteriocin pyocin S2.

The effects of pyocin S2, a bacteriocin produced by Pseudomonas aeruginosa strain M47, on several processes in susceptible bacterium have been examined. Lipid synthesis, measured in terms of [32P]phosphate, [14C]acetate or [2-3H]glycerol incorporation into lipid fractions, was halted almost completely soon after pyocin S2 addition. When cell suspensions were treated with various amounts of pyocin S2, the extent of inhibition of lipid synthesis was proportional to the ratio of killed bacteria. Protein synthesis was not essential for the inhibition. Degradation of lipid due to pyocin S2 was not detected. Pyocin S2 also affected protein and nucleic acid syntheses, but these inhibitions appeared with a delay of about 10 min after the cessation of lipid synthesis. The effect of trypsin [EC 3.4.21.4] on the viability of cells which had adsorbed pyocin S2 was also investigated: the cells went through a period when the destruction of pyocin S2 by trypsin restored the colony-forming ability of the cells (stage I). Then transition to a second state in which the cells lost viability irrespective of trypsin treatment (stage II) took place. The transition from stage I to stage II depended on the energy metabolism of the cells and followed first-order kinetics with a rate proportional to the number of killing units of adsorbed pyocin S2. The residual capacity for lipid synthesis in cells which had adsorbed pyocin S2 after trypsin treatment at various times indicated that lipid synthesis was inhibited only in the cells at stage II of pyocin S2 action.

Acetates↗
PubMed1979

Biochemical properties of a new flexuous bacteriocin, pyocin F1, produced by Pseudomonas aeruginosa.

Pseudomonas aeruginosa strain P15 produces not only pyocin R1 and phage PS10, but also a substance having a flexuous rod structure, the nature of which is so far unknown. A variant strain (P15--40) was obtained which produced these flexuous particles more effectively than the original strain, and the particles were purified to homogeneity and investigated. Several strains of P. aeruginosa were found to be killed by the particles. It was concluded that the flexuous rod-like particles are not related to pyocin R1 or phage PS10, but represent a new pyocin, which we have designated as pyocin F1. Pyocin F1 showed a different action spectrum and a different pattern on SDS-polyacrylamide gel electrophoresis from either pyocin R1 or phage PS10. The killing activity of pyocin F1 was of single-hit type. The activity was not affected by anti-R1, anti-R1-core or anti-PS10, or by DNase, RNase, pronase or trypsin, but was completely destroyed by treatment at 70 degrees C for 10 min. Some cofactor was required for the adsorption of this pyocin on sensitive bacteria. Another flexuous bacteriocin was also found and named pyocin F2.

Bacteriocins↗
PubMed1989

Relationship of antibiotic resistance phenotype to the R-pyocin susceptibility pattern in clinical isolates of Pseudomonas aeruginosa.

One hundred sixteen clinical isolates of Pseudomonas aeruginosa were collected from 7 hospitals in Athens. All strains were studied for their susceptibility to cefotaxime, ceftazidime, carbenicillin, aztreonam, imipenem, nalidixic acid, ciprofloxacin, gentamicin, and chloramphenicol. In addition, the R-pyocin susceptibility pattern was determined and the strains were O-serotyped and tested for their agglutination in acriflavine. The isolates included 53 strains resistant to both gentamicin and carbenicillin, 13 to carbenicillin only, 20 to gentamicin only, and 30 sensitive to gentamicin and carbenicillin. The multiresistant isolates displayed relatively higher resistance to all other antibiotics except aztreonam and cefotaxime. Remarkably 30 out of 53 multiresistant isolates reacted with one pyocin only, namely pyocin R2. This R-pyocin response was not encountered in any other strains of the other antibiotic resistance phenotypes. These isolates belonged to the 0-12 serogroup. The 0-12 serogroup was represented only in a minority of strains giving other R-pyocin reactions. It is interesting that strains reacting with pyocin R5 only were mostly susceptible to antibiotics. The results clearly indicate lipopolysaccharide-core mutations in multiresistant clinical isolates of P. aeruginosa. Despite the fact that the R-pyocin resistance pattern can not define the precise possible defect, the multiple and high level resistance associated with R2-pyocin reaction seems to be an interesting trait.

Bacteriocins↗
PubMed1978

Mode of action of pyocin R1.

The effects of pyocin Rl on transport systems and syntheses of macromolecules in Pseudomonas aeruginosa strain P14 were studied under two conditions, 0.4 mM and 40 mM Magnesium ions. In the presence of 0.4 mM magnesium ions, the incorporation of [14C]leucine into protein and the uptake of [14C]leucine into the leucine pool were completely inhibited by pyocin. Furthermore, [14C]leucine which had been taken up into the leucine pool was depleted by pyocin. Comparing the concentration of amino acid within cells with that in the medium, it was concluded that the active transport in P14 cells was inhibited completely by pyocin. Such an effect of pyocin Rl on transport systems was not specific to leucine but common to many amino acids and uridine. On the other hand, under the condition of 40 mM magnesium ions, [14C]-leucine once accumulated was not depleted by pyocin, but uptake of [14C]leucine into the leucine pool stopped immediately while incorporation of [14C]leucine into protein continued at a considerably reduced rate; therefore the machinery for protein synthesis was not directly inhibited by pyocin. It is suggested that the loss from the amino acid pool in cells brings about the rapid cessation of protein synthesis under the condition of 0.4 mM magnesium.

Bacterial Proteins↗
PubMed1977

Pyocin sensitivity of Neisseria gonorrhoeae and its feasibility as an epidemiological tool.

Pyocin inhibition of Neisseria gonorrhoeae and its feasibility as a gonococcal typing scheme were examined. Mitomycin C-induced pyocin lysates of Pseudomonas aeruginosa were able to selectively inhibit the growth of gonococcal strains. The particles associated with the inhibitory activity were non-dialyzable, heat labile, Pronase sensitive, trypsin resistant, and of large molecular weight by membrane and gel filtration techniques. The inhibitory activity was shown to be specific by absorption with sensitive and insensitive strains of N. gonorrhoeae and P. aeruginosa. Partial purification of pyocin lysates by ammonium sulfate precipitation followed by ultracentrifugation revealed phagelike particles consistent with high-molecular-weight R-type pyocines. These particles were associated with increased inhibitory activity and could be seen associated with the gonococcal cell surface. One hundred and six gonococcal strains could be differentiated on the basis of their sensitivity of 23 pyocin extracts. Thirty different patterns of pyocin inhibition were seen. Isolates from different body sites from the same patient could generally be identified as being similar strains. Strains isolated from known consorts had the same patterns. In general, agreement between pyocin typing and available epidemiological information was good.

Bacteriocins↗
PubMed1989

Genetic comparison of bacteriophage PS17 and Pseudomonas aeruginosa R-type pyocin.

PS17 is a bacteriophage of Pseudomonas aeruginosa that is serologically cross-reactive with phage tail-like bacteriocins called R-type pyocins. In addition to having immunological cross-reactivity, certain genes are functionally complementable between PS17 and R-type pyocins. To compare the genetic structures of PS17 and R-type pyocins, a physical map of PS17 genes was constructed by cloning phage DNA fragments on RSF1010-derived vector plasmids. The head and tail gene clusters were tandemly arrayed and together occupied about half of the 41-kilobase-pair PS17 chromosome. With use of these phage clones, the following results were obtained with respect to the genetic relationship between PS17 and R-type pyocins: (i) serological cross-reaction between PS17 and pyocin occurred for the major sheath protein and two components of the fiber, (ii) a certain pyocin mutation was complemented by cloned phage fragments, and (iii) the phage DNA fragment carrying sheath and core tube genes was shown to hybridize to the DNA fragment carrying the pyocin R2 genes.

Bacteriocins↗
PubMed1976

Treatment of Pseudomonas aeruginosa infections with pyocines.

The interactions of a contractile, a filamentous and a small pyocine with a sensitive strain of Pseudomonas aeruginosa (no. P14) were examined in vivo. The purification procedure used yielded high-activity pyocine preparations that were not toxic to mice. The inhibitory activity of such preparations, when injected into mice by various routes, was retained for up to 24 h. However, high molecular-weight pyocines given intraperitoneally in the presence of a lethal dose of strain P14 administered by the same route did not prevent the fatal outcome of infection unless they are given before or together with the bacteria. The small pyocine had no protective effect. In burned mice infected with strain P14, topical application of a filamentous pyocine failed to improve the chances of survival. The results suggest that there is little future for pyocine therapy.

Administration, Topical↗
PubMed1975

Defective pyocin particles produced by some mutant strains of Pseudomonas aeruginosa.

Mutants of Pseudomonas aeruginosa, defective in the production of active R-type pyocins, were isolated from pyocinogenic strains and their products were characterized. Polysheath-like structures were found in induced lysates of 29 out of 42 mutants. Two mutants (strain P15-16 and M189) were found to produce special defective particles, which were characterized in detail. The other 11 mutants did not produce significant amounts of any structure visible under an electron microscope. Serum blocking powers were found in lysates from P15-16 and M189 to significant amounts. Defective particle produced by strain P15-16 lacked the sheath component, whereas M189 had morphological defects at the junction between sheath and baseplate, and also in the architecture of baseplate. Both defective particles could adsorb to the surface of bacteria, that were sensitive to pyocin, at the tip of their fibers without killing cells. All M189 particles attached to the bacteria had the extended sheaths. Therefore, attachment to the bacteria by fibers is not sufficient to kill cells, and contraction of sheath must occur after the initial adsorption by fibers for pyocin to express its biological activity. Defective particles of strain P15-16, which was derived from strain P15 (a pyocin R1 producer), could be converted to active forms by an in vitro complementation reaction with extracts from certain mutants originated from strain PAO (a pyocin R2 producer). This result indicated the exchangeability of components between R-type pyocins belonging to the different groups.

Adsorption↗
PubMed1991

The structural basis for pyocin resistance in Neisseria gonorrhoeae lipooligosaccharides.

Pyocin resistance in a strain of Neisseria gonorrhoeae has been found to be associated with structural differences in the oligosaccharide moieties of the gonococcal outer membrane lipooligosaccharides (LOS). N. gonorrhoeae strain 1291 had been treated with several pyocins, usually lethal bacteriocins produced by Pseudomonas aeruginosa, and a series of surviving mutants were selected. The LOS of these pyocin-resistant mutants had altered electrophoretic mobilities in sodium dodecyl sulfate-polyacrylamide gels (Dudas, K. C., and Apicella, M. A. (1988) Infect. Immun. 56, 499-504). Structural analyses of the oligosaccharide portions of the wild-type (1291 wt) and five pyocin-resistant strains (1291a-e) by liquid secondary ion mass spectrometry, tandem mass spectrometry, and methylation analysis revealed that four of the mutant strains make oligosaccharides that differ from the wild-type LOS by successive saccharide deletions (1291a,c-e) and, in the oligosaccharide of 1291b, by the addition of a terminal Gal to the 1291c structure. The composition, sequence, and linkages of the terminal tetrasaccharide of the wild-type LOS are the same as the lacto-N-neotetraose terminus of the human paragloboside (Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc-ceramide), and both glycolipids bound the same monoclonal antibodies O6B4/3F11 that recognize this terminal epitope. None of the pyocin-resistant mutants bound this antibody. The 1291b LOS bound a monoclonal antibody that is specific for Gal alpha 1----4Gal beta 1----4Glc-ceramide (Pk glycosphingolipid) and shared a common composition, sequence, and linkages with this latter glycosphingolipid. Organisms that bound the anti-Pk monoclone occurred at the rate of approximately 1/750 among the wild-type parent strain. This structural information supports the conclusion that treatment with pyocin selects for mutants with truncated LOS structures and suggests that the oligosaccharides contained in the LOS of the wild-type strain and 1291b mimic those of human glycosphingolipids.

Carbohydrate Sequence↗
PubMed1990

Purification of the pyocin S2 complex from Pseudomonas aeruginosa PAO1: analysis of DNase activity.

Pyocin S2 purified from mitomycin C-induced lysates of Pseudomonas aeruginosa strain PAO1 has been shown to consist of a complex of two proteins. Further analysis of the purified S2 complex revealed that the 74 kd S2 pyocin demonstrates DNase activity which can be blocked by S2-specific antisera. Chromosomal DNA from pyocin sensitive cells treated with the pyocin S2 complex in vitro did not show any degradation, suggesting that the 10 kd protein inhibits the DNase activity of the S2 protein. These results suggest an alternative mechanism for the toxicity associated with the S2 pyocin.

Antibodies, Monoclonal↗
PubMed1979

Studies on a receptor for pyocin in a R mutant of Salmonella minnesota.

Lipopolysaccharide (LPS) isolated from the pyocin sensitive R form strain of Salmonella minnesota F6 (chemotype Rd1) inhibited the activity of bacteriophage tail-like pyocin P1 whereas no inhibition occurred with LPS prepared from the pyocin resistant S form of S. minnesota. Subunits of lipopolysaccharide obtained by treatment with sodium deoxycholate and the polysaccharide fraction of the lipopolysaccharide obtained by acid hydrolysis were shown to be still active whereas lipid A fraction had no pyocin neutralizing activity. The (KDO)3-hepI-hepII unit, which terminates the lipopolysaccharide of S. minnesota F6 was, therefore, suggested to determine the specificity of the pyocin P1 receptor.

Bacteriocins↗
PubMed1992

[Pyocin typing of Pseudomonas aeruginosa strains isolated from various sources].

In our study, 103 strains of P.aeruginosa from various clinical specimens were typed by pyocin typing method with 13 indicator strains. As a result of pyocin typing, 18 different pyocin type were detected from 81 typable strains (78.6%), 22 of P.aeruginosa strains (21.3%) could not be typed because of the lack of their pyocin activity. On the other hand, 2 of typable P.aeruginosa strains were found to produce inhibition patterns that differed from standard inhibition patterns according to Govan and Gillies Method. Because of this reason, these two strains could not be classified. As a result of our study, it was observed that, strains that belong to pyocin type-1 were in majority. It was detected that, TSA Medium supplemented with 5% sheep blood can be used easily instead of TSA Medium, supplemented with 5% horse blood.

Culture Media↗
PubMed1978

Isolation, purification and characterization of a pyocin.

Seventeen strains of P. aeruginosa were tested for pyocin production using the broth method. Mitomycin C was used for the induction of pyocin in TSB shaked cultures incubated at 32 degrees. The highest pyocin activity was produced by strain 14. TSB shaked cultures in fluting flasks were found to be superior to Erlenmeyer flasks for pyocin production. Pyocin 14 was purified by chemical and chromatographic methods. It was found to be protein in nature and free from carbohydrates. It is stable between pH 5 and 9 and is partially inactivated when kept for one month at 4 degrees. Freezing and thawing, lyophilization and heating at 65 degrees for 5 min completely destroyed its activity. The addition of 4 mg/ml bovine albumin or 2 mg/ml gelatin caused about 60% increase in activity. However, treatment with 10 mM EDTA caused a 98% drop in its activity.

Bacteriocins↗
PubMed1979

Pseudomonas aeruginosa bacteremia: relationship of bacterial enzyme production and pyocine types with clinical prognosis in 100 patients.

Strains of Pseudomonas aeruginosa were studied from 100 patients with bacteremia. In vitro quantitation of extracellular enzymes (lecithinase, protease, and elastase) and pyocine typing of these isolates were performed. No significant difference was found in the quantity of the enzymes produced or in the pyocine types by isolates obtained from patients dying from bacteremia or surviving this serious infection. Quantitation of the extracellular enzymes and pyocine types of blood isolates were contrasted with similar data obtained from sputum, urine, and skin isolates. One third of all strains produced minimal or no extracellular enzymes regardless of their source. However, the highest enzyme-producing strains were observed in the blood isolates. Although a greater variability of pyocine types was found in blood culture isolates, there was no significant difference between the pyocine types found in blood, urine, sputum, or skin isolates. The lack of correlation between the in vitro quantity of lecithinase, protease, and elastase produced by P. aeruginosa strains isolated from bacteremic patients and the prognosis of these patients supports the possible local rather than systemic significance of these extracellular enzymes in the pathogenesis of P. aeruginosa bacteremia.

Extracellular Space↗
PubMed1977

A fluorescent probe response to the interaction of pyocin R1 with sensitive cells.

Additon of pyocin R1, a bacteriocin of Pseudomonas aeruginosa, to sensitive cells caused a fluorescence increase of 8-anilino-1-naphthalenesulfonate (ANS) in the cell suspension. The reaction was rapid, starting with a short time lag after adsorption of pyocin onto the cells and finishing within several minutes. The fluorescence response was attributed to the interaction of the cell body and ANS, not to that of the medium outside the cells and ANS. The maximal amplitude of fluorescence after pyocin addition was dependent on temperature, and the relation appeared to be biphasic. Similarly, Arrhenius plots of the initial rate of fluorescence change were biphasic. The transition of slopes in both cases occurred in the temperature range between 18 and 19 degrees. These results suggest that ANS interacts with lipids in the cell envelope and that pyocin causes a structural change of the cell envelope leading to increased fluorescence of ANS.

1-Naphthylamine↗
PubMed1978

Effect of pyocin R1 on the glucose metabolism of sensitive cells of Pseudomonas aeruginosa.

The effect of pyocin R1 on the glucose metabolism of sensitive Pseudomonas cells was investigated. Upon treatment with pyocin R1, although the rate of O2 uptake of the sensitive cells for glucose or gluconate was not very much affected at first, the final level of O2 uptake was greatly reduced. When 2-oxogluconate was used as a substrate, O2 uptake was immediately halted by pyocin. By determining the amounts of glucose, gluconate, and 2-oxogluconate before and after the reaction and the amount of O2 consumed, it was concluded that glucose was exclusively metabolized via the following pathway with quantitative accumulation of 2-oxogluconate after pyocin treatment. (Formula: see text). The possible mechanism of this change is discussed.

Bacteriocins↗