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At least 487 records · Page 27Linked to original sources
PubMed1984

Evaluation of a typing scheme for group A streptococci based upon bacteriocin-like inhibitor production.

A method of typing (P-typing) streptococci according to their production of inhibitory activity against a set of 9 indicator strains has been evaluated. Modifications to a previously described P-typing procedure have been made which improve the reproducibility of the method and also reduce the proportion of untypable strains. The test conditions, particularly medium composition, incubation temperature and aeration were found to be critical determinants of inhibitor production and must be carefully controlled. The use of certain commercial sources of Blood Agar Base and the presence of human blood in the typing medium are requirements for detection of some inhibitors, particularly for P-type 777 strains. The previously "standardized" conditions for P-typing specify incubation of the test strains aerobically at 32 degrees C. However, in order to increase the proportion of typable strains an additional set of cultures should be incubated anaerobically. Anaerobic incubation was found to be essential for the production of bacteriocin-like inhibitors by M-type 49 strains and markedly increased inhibitor production by M-type 4 and M-type 57 strains. Also associated with anaerobic incubation was an increase in the amount of non-specific, acid-mediated inhibition, but this could be eliminated by buffering the typing medium with 0.5% (w/v) calcium carbonate. The epidemiological validity of P-typing was tested in a survey of group A streptococcus carriage in a school and in 9 family groupings. Inhibitor production appeared to be a stable strain marker and the occurrence of some P-type subdivisions within clusters of strains having identical serotype patterns indicates that combined application of serotyping and P-typing may give improved strain discrimination.

Bacteriocins↗
PubMed1983

[Inhibition of the growth of bacterial populations by suspensions obtained from Pseudomonas aeruginosa pyocinogenic strains].

Suspensions obtained from five Pseudomonas aeruginosa pyocinogenic strains showed inhibitory and variable activity against bacterial strains belonging to the Nocardiaceae, Micrococcaceae, Neisseriaceae, Streptococcaceae, Vibrionaceae, Enterobacteriaceae, and Pseudomonadaceae families. Under special conditions, the same pyocinogenic P. aeruginosa strain can be affected by it own suspensions. These pyocinlike particles could be considered as a regulatory factor acting on the rate and size of the population growth.

Bacteria↗
PubMed1982

[Experimental immunological effectiveness and safety of pyoimmunogen vaccine against Pseudomonas aeruginosa infection].

Pyoimmunogen, a polycomponent vaccine against P. aeruginosa infection, has been obtained in laboratory and semi-industrial conditions. The microbial biomass obtained from the strains belonging to O-serotypes (immunotypes) most frequently occurring in clinical practice has been used for producing protective antigens. The preparations have been found to contain proteins (peptides) and carbohydrates in the ratio 6 : 1 to 8 : 1, as well as traces of 2-keto-3-desoxyoctanate, which is indicative of the low content of endotoxin. The immunogenicity of the preparations has been studied experimentally by the active immunization of mice. In these experiments the animals vaccinated in a single injection were found to be protected from challenge with both homologous and heterologous P. aeruginosa strains. The high level of protection from infection caused by toxigenic strain PA-103 was registered. The preparations have low toxicity: LD50 for mice exceeds 2 mg (in protein content): after the multiple administration (7-10 times) of the preparation to mice and rats the weight of the experimental animals was not significantly different from the weight of the control animals.

Animals↗
PubMedDate not supplied

[A complementary phage-typing scheme for "P. aeruginosa" (author's transl)].

Twenty per cent of Pseudomonas aeruginosa strains isolated in Portugal are non typable with the phage-typing Lindberg system, but most of them may be typed with the aid of a new phage-typing method. This complementary scheme of phage-typing is based on the use of 15 new phages from sewage; 39 phage-types were found among a group of the non-typable strains isolated in several hospitals in Lisbonne. The relations between the serotypes, the pyocinotypes and the new lysotypes are investigated.

Bacteriophage Typing↗
PubMed1993

[Prevalence of serotype 0:12 among strains of P. aeruginosa causing nosocomial infection in Spain (1980-1991)].

BACKGROUND: The aim of the present study was to characterize P. aeruginosa strains causing nosocomial infection in Spain between 1980-1990 with special emphasis on the incidence of serotype 0:12 strains. METHODS: 11,411 strains of P. aeruginosa from hospital-acquired infections were studied and epidemiologically characterized by phage-typing, serotyping and sensitivity to antimicrobial agents. The strains of the 0:12 serotype were analyzed by isoenzyme analysis. RESULTS: Although the major serotypes throughout the period studied were: 0:1, 0:6 and 0:11, the existence of serotype 0:12 strains (6%) were detected which had produced nosocomial outbreaks in surrounding countries. This serotype is homogeneous in that the epidemiologic markers and patterns of sensitivity to antibiotics and the multienzyme analysis demonstrate uniformity in the electrophoretic patterns of all the strains studied. CONCLUSIONS: The 0:12 serotype is in Spain indistinguishable by phage typing and studies of antibiotic sensitivity. It may be considered as being of clonal origin and is probably equal to that existing elsewhere in Europe.

Bacterial Proteins↗