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PubMed1984

Revised pyocin typing method for Pseudomonas aeruginosa.

In the Gillies and Govan method of pyocin typing for Pseudomonas aeruginosa a cross-streaking technique was used, and 105 main types and 25 subtypes were identified by the patterns of inhibition observed on 13 indicator strains. Disadvantages of the technique included the need to remove test strain growth before application of the indicator strains, the 48-h period needed to obtain a result, and the inability to reliably type mucoid P. aeruginosa. Recent studies have enabled us to overcome these disadvantages and significantly improve the speed and application of pyocin typing. Our revised technique utilizes the same 13 indicator strains which are already used internationally. Test strains were rapidly applied to the surface of agar plates with a multiple inoculator. After incubation for 6 h and exposure to chloroform, the indicator strains were applied in agar overlays without prior removal of the test strain growth. After 18 h of incubation, the pyocin type was recognized by inhibition of particular indicator strains. Additionally, the activity of particulate (R and F) and nonparticulate (S) pyocins could be distinguished on the basis of inhibition zone size, which thus allowed further discrimination. The revised technique allows typing within 24 h, increases the number of identifiable types, and can be used to type mucoid strains.

Bacteriocins↗

PubMed1986

Improved, computer-generated system for pyocin typing of Pseudomonas aeruginosa.

We applied numerical clustering algorithms to the selection of a new indicator strain set for the pyocin typing of Pseudomonas aeruginosa. The new indicator set is composed of selected indicator strains from the sets described in 1966 by Gillies and Govan (J. Pathol. Bacteriol. 91:339-345) and in 1974 by Jones, Zakanycz, Thomas, and Farmer (Appl. Microbiol. 27:400-406) and is designated the G-F set. This indicator set consists of 14 indicator strains which typed 99.5% of 114 test cultures, has a high degree of discrimination (10 patterns encompass 50% of the test strains), and provides 62.3% reproducibility of the same typing pattern in duplicate tests done on different days. The G-F set of indicator strains provides slightly higher percentages of typable cultures than either of the other two sets, has greater discriminatory capability, and is more reproducible than they are. We recommend that the G-F set of indicator strains be used instead of the two other sets for pyocin typing of P. aeruginosa. We also tested a recently described overlay procedure for pyocin testing of P. aeruginosa and found it to be superior to previous methods in that it is easier to perform, it provides answers in only 24 h instead of 48 h, and it can be used to type mucoid strains (which previous techniques could not readily do). Thus, the application of numerical clustering algorithms and use of a revised typing procedure have produced an improved system for pyocin typing of P. aeruginosa. Similar procedures may be applicable to other typing systems.

Algorithms↗

PubMed1976

Epidemiology of Pseudomonas aeruginosa infections: determination by pyocin typing.

The epidemiology of hospital infections due to Pseudomonas aeruginosa was investigated by pyocin typing. The typing method, which determined the pyocin activity of clinical isolates of P. aeruginosa on 27 indicator strains, was 43.7% reproducible, but elimination of 9 indicator strains doubled the reproducibility and yielded more readable pyocin inhibition zones. Seventy-eight of 1,084 isolates (7.2%) were untypable. In the second part of the study, P. aeruginosa was isolated from 110 patients (5.4% of all admissions) in a 3-month period and typed with the revised method. Twenty pyocin types were identified, 10 of which were obtained from five or more patients. P. aeruginosa was isolated from 45 of 353 environmental samples, including water fountains, ice machines, bar soaps, and germicide solutions for toilet brushes. Twenty percent of the environmental samples were untypable but, among typable strains, the five most common environmental strains were the same as the strains most frequently isolated from patients. The organism was frequently isolated from noses (39%), throats (39%), and stools (29%) of patients with P. aeruginosa infections or colonizations in urine, sputum, surgical wounds, or skin lesions. Six of eight patients had P. aeruginosa in their tracheostomy wounds. Autoinfections by strains already acquired on carrier sites may be significant.

Bacteriocins↗

PubMedDate not supplied

Pyocine typing of Pseudomonas aeruginosa strains isolated in Ahmadu Bello University Teaching Hospital, Zaria.

Pseudomonas aeruginosa strains isolated from clinical and environmental sources in Ahmadu Bello University Teaching Hospital, Zaria, were pyocine typed using the indicator strains and the standardized method of Gillies & Govan. Out of 302 clinical isolates 9.6% were untypable and 3.6% were unclassifiable. Among typable isolates fourteen pyocine types were identified, types 1, 3, 11, 5, and 10 being the commonest. Among ninety-six environmental isolates types 1, 3 and 10 were most common, 18.7% were untypable and 3.1% were unclassifiable. Sink traps were environmental sites most frequently contaminated with Ps. aeruginosa. Out of ten pyocine types identified in environmental strains, eight were the same as those isolated from patients. Seven subtypes were found among the most commonly encountered pyocine type 1 isolates. The procedure is a simple and reliable method to study the epidemiology of infections due to Ps. aeruginosa.

Bacteriocins↗

PubMed1989

[Bactericidal spectrum of pyocins on strains collected at Region IX and X hospitals in Chile].

The inhibitory effect of 5 pyocins produced by wildstrains of Ps aeruginosa was tested by qualitative and quantitative techniques. 313 strains of 4 species: E coli, P vulgaris, Ps aeruginosa and St aureus were assayed. It was shown that the most active pyocin was P37, which inhibited 276 out of 313 strains tested. About 80% of E coli and 90% of St aureus strains were inhibited by the pyocins under being tested. It was established that sensitivity to pyocin was not restricted to close-related species but extends to unrelated families also.

Bacteriocins↗

PubMed1985

Characterization of Pseudomonas aeruginosa isolated from drinking water by serogrouping, phage sensitivity and pyocin pattern.

Pseudomonas aeruginosa strains isolated in the years 1977-1981 from drinking water samples fell into a large number of epidemiological units determined on the basis of serogroups, phage sensitivity and pyocin pattern. Strains isolated from water were, as a rule, sensitive to more phages than strains cultured from clinical material. The 427 water isolates fell into 8 serogroups and 31 pyocin patterns; 25.1% were untypable by the pyocin method. The frequency of isolation of different phage patterns varied annually. The most frequent epidemiological unit, comprising 9.1% of the isolates, was (serogroup: phage pattern: pyocin pattern) O1: 2/7/16/21/44/68/73/F7/F8/109/119x/352/1214/M4/C11/C18/C21:12 3567; 73.8% of the strains belonged to epidemiological units each represented by less than 4 strains. The large number of epidemiological units indicated that the distribution system had frequently been polluted with P. aeruginosa at different sites, but the organism was unable to invade the whole water supply system.

Bacteriolysis↗

PubMed1984

[Pyocin typing of Pseudomonas aeruginosa strains].

The possibility of using the typing of P. aeruginosa strains by their pyocins as one of the epidemiological markers in the study of P. aeruginosa hospital infections has been established. As this method of typing is characterized by certain variability, the authors propose that the method of the "cross analysis" of pyocins produced by P. aeruginosa strains be used simultaneously. This method is based on the following phenomenon: if the cultures to be compared are different, the pyocin produced by one strain suppresses the growth of the other one, and if the cultures are identical, no suppression of their growth by pyocins is observed.

Bacteriocins↗

PubMed1981

[Pyocine typing of Pseudomonas aeruginosa strains from nosocomial outbreaks - after the elimination of possible sources of mistakes by heat-treatment (author's transl)].

In 25% of the freshly cultivated Pseudomonas aeruginosa strains (isolated from nosocomial infections) a change of the pyocine type determined according to the method of Gillies and Govan results from passages on selective or non-selective media or from several days' storage at room temperature (Tab. 1 and 2). This inconstancy of the pyocine type can be avoided by exposure of the strains to 56 degrees C for 5-75 min. After this heat treatment the agarose-gel-electrophoresis of the strains shows the loss of all non-conjugative plasmids smaller than 25 kbp (Fig. 2). By typing more than 1,000 strains from nosocomial Pyocyaneus outbreaks we could demonstrate the reliability of the pyocine typing after having cured the strains by heat. Further we propose a binary numbering system for the pyocine types using the results of the 8 indicator strains (Tab. 3).

Bacteriocins↗

PubMed1975

Epidemiology of Pseudomonas aeruginosa infections investigated by pyocin typing.

All strains of Pseudomonas aeruginosa isolated in a large Canadian hospital over a 3-year period were typed by their pyocin production. Smaller collections of P. aeruginosa from other hospitals were also typed. Almost 3000 strains were examined. The typing method did not require use of complex reagents and was successful in subdividing P. aeruginosa into numerous types. No single type was restricted to infections of one particular kind. Infections of all kinds were associated with a wide variety of pyocin types. Extensive crossinfection with one particular pyocin type was observed only in urinary infection of patients with urologic disorders. The four pyocin types that were most frequent in our entire series have been reported as the commonest types causing infections in many other parts of the world.

Cross Infection↗

PubMed1975

[Typing of pseudomonas aeruginosa by pyocine production. Experiments with a simplified method using four indicator strains (author's transl)].

A further differentiation of strains of Pseudomonas aeruginosa which have been isolated from clinical material is desirable because of the increasing frequency of hospital infections caused by this species. Only by such a procedure cross infections which require hygienic measures can be distinguished from autoinfections. Pyocine typing with a set of only four indicator strains was tried by repeated typing of 542 strains. Because of its simplicity and the small amount of material and working time required the method was found to be suitable for routine application. Reproducibility was satisfactory. The strains tested could be grouped into nine different pyocine types. Similar to the results of other typing procedures, 74 per cent of the strains belonged to three groups. The method is suitable for detection of sources of hospital infections caused by the more rare pyocine types. By a comparison of the antibiotic resistance patterns with pyocine types in strains which had been isolated from patients with chronic infections it was demonstrated that antibiotic resistance patterns could not be used as criteria for epidemiological investigations.

Bacteriocins↗

PubMed1976

[Comparative pyocine typing of Pseudomonas aeruginosa with different indicator sets (author's transl)].

In a comparative study, 336 strains of Ps. aeruginosa were typed by their pyocine production with the indicator-sets of Gillies and Govan, Govan and Gillies, and with the author's set. The results obtained by either of the three sets of indicators showed a high degree of correlation with the results obtained by means of other sets. These correlations allow a subdivision of strains of Pseudomonas aeruginosa into four major subgroups. The possible reasons for the existence of such subgroups and for the correlations between pyocine types and serological groups, which have been demonstrated by other authors, are discussed. For practical purposes and epidemiological investigations the advantages of combined pyocine typing with different sets of indicators are discussed, and a combination of the indicators of Govan and Gillies with the author's set is recommended, giving the most even distribution of epidemiologically unrelated strains of Ps. aeruginosa among different pyocine types with the smallest possible number of indicators.

Bacteriocins↗

PubMed1988

Purification and characterization of pyocins R from Pseudomonas aeruginosa.

Five types of pyocins were found in Pseudomonas aeruginosa strain 112. Production of these types was induced by UV irradiation. The pyocin activity was found to be resistant to trypsin treatment. Their molar mass was found to be 282, 251, 112, 89.1 and 54.9 kg/mol, respectively. The pyocins obtained were different from any known type (such as R, S, F) in their chemical and physical properties.

Bacteriocins↗

PubMed1983

Chemical and immunochemical studies on lipopolysaccharides from pyocin 103-sensitive and -resistant Neisseria gonorrhoeae.

The chemical and immunochemical properties of lipopolysaccharides (LPS) isolated from pyocin 103-sensitive and -resistant Neisseria gonorrheae were investigated. Marked differences were found in immunochemical behavior of LPS from pyocin-sensitive gonococcal strain JW31 and its isogenic pyocin-resistant variant JW31R. JW31 LPS readily precipitated wheat-germ agglutinin, soybean lectin, and rabbit anti-Streptococcus faecalis or horse anti-type 14 pneumococcal antibody. In contrast, JW31R LPS precipitated only soybean lectin. The combining-site specificity of anti-S. faecalis cross-precipitated by JW31 LPS, or type 14 pneumococcal capsular polysaccharide, was examined by hapten inhibition, and lactose found to be the most potent inhibitor. Horse anti-pneumococcal type 14 antibodies, cross-precipitated by JW31 LPS and streptococcal lactose polymer, exhibited heterogeneity with respect to combining site specificity. Gel filtration of LPS-derived core oligosaccharide showed both strain JW31 and JW31 R to possess R-type lipopolysaccharide with cores having a Mr approximately 1800. JW31R LPS contains more galactose but less hexosamine than JW31 LPS. Both JW31 and JW31R core oligosaccharides possess D-glucosamine and D-galactosamine, probably N-acetylated, as the only nonreducing end-groups, and (1 leads to 4)-linked D-glucose residues. Chemical data support immunochemical findings which indicate that lactose units occur as a structural feature of JW31 gonococcal LPS.

Bacteriocins↗

PubMed1975

Subunit arrangement in the extended sheath of pyocin R.

An optical diffraction study has been made of electron micrographs of extended sheaths of pyocin R. It has been demonstrated that the extended sheath consists of annuli of six subunits, which are arranged in a helix of 3.57 annuli per one turn. The annulus repeat in the helix direction is 35A. The dimensions and probably the helical parameters of pyocin R sheath are different from those of T4 phage tail, but a structural correlation appears to exist between the extended sheath of pyocin R and that of the phage tail.

Bacteriocins↗

PubMed1979

Sulfhydryl groups of pyocin R1. Morphology and activity modified with sulfhydryl reagents.

Electron microscopic observation of pyocin R1 with the negative staining technique demonstrated that pyocin R1 retained its phage tail-like shape of an extended sheath even when it was inactivated by treatment with p-chloromercuribenzoic acid (PCMB) or 4-(p-sulfophenylazo)-2-mercuriphenol (SAMP). Thus it was shown that the contraction and extension of the sheath does not occur reversibly on the modification of sulfhydryl groups accompanying the change of activity. The activity lost under these conditions was restored to the original level by treatment with 2-mercaptoethanol (2-ME). Numbers of sulfhydryl groups in the pyocin R1 particle were determined to be 208 mol and 152 mol per mol (11.8 x 10(6) daltons) by spectrophotometric titration with SAMP and by membrane-filter assay with radioactive PCMB, respectively. Most of these cysteine residues appeared to be localized in the substructure other than the sheath and core. It was also shown that all of these sulfhydryl groups were not necessary for expression of its activity but a part of them were essential for adsorption to the sensitive cells.

Bacteriocins↗

PubMedDate not supplied

Inhibition of active transport and macromolecular synthesis by pyocin 103 in Neisseria gonorrhoeae.

The mechanism of inhibition of Neisseria gonorrhoeae by pyocin 103 was examined. Pyocin 103 decreases the viability of N. gonorrhoeae immediately after its addition to logarithmically growing cells by single-hit kinetics. This inhibition was paralleled by an immediate cessation of protein synthesis, RNA synthesis, and active transport. From the data presented, it is likely that pyocin kills N. gonorrhoeae in the same manner that it kills Pseudomonas aeruginosa, i.e., by interfering with energy metabolism.

Bacterial Proteins↗

PubMed1980

Pyocin inhibition of Neisseria gonorrhoeae: mechanism of action.

Purified R-type pyocins (611 131) from Pseudomonas aeruginosa PA103 exhibited bactericidal activity against Neisseria gonorrhoeae. Killing of gonococci was a single-hit process requiring as few as 1 pyocin per colony-forming unit. Deoxyriboinucleic acid, ribonucleic acid, protein, and lipid syntheses were rapidly and completely inhibited. Oxygen uptake was also inhibited, but occurred after the inhibition of macromolecular synthesis. The cell lysis which occurred after pyocin inhibition of gonococcal growth was the result of endogenous gonococcal autolysin activity.

Adenine↗

PubMed1999

Uptake of pyocin S3 occurs through the outer membrane ferripyoverdine type II receptor of Pseudomonas aeruginosa.

Pyocin S3 was found to kill exclusively Pseudomonas aeruginosa isolates producing type II pyoverdine (exemplified by strain ATCC 27853). Killing was specifically inhibited by addition of type II ferripyoverdine. All Tn5 mutants resistant to pyocin S3 were defective for pyoverdine-mediated iron uptake and failed to produce an 85-kDa iron-repressed outer membrane protein. We conclude that this protein is probably the type II ferripyoverdine receptor that is used by pyocin S3 to gain entry into the cell.

Bacterial Outer Membrane Proteins↗