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Biomedical subjects

G Młynarczyk

Publications and source records attributed to G Młynarczyk.

At least 37 records · Page 2Linked to original sources
PubMed1993

Phage-related conversion of enterotoxin A, staphylokinase and beta-toxin in Staphylococcus aureus.

The conversion of enterotoxin A, staphylokinase and beta-toxin in Staphylococcus aureus is related with lysogeny stage. Bacteriophages able to convert enterotoxin A were used for lysogenization of the standard NCTC 8325-4 strain. Lysogenic, enterotoxigenic derivatives of this strain were characterized. The conversion of enterotoxin A was obtained in 7 examined derivatives, the conversion of enterotoxin A and staphylokinase at the same time was obtained in one case and the loss of beta hemolysin production ability was observed in all of 8 examined derivatives of the NCTC 8325-4 standard strain.

Bacterial Toxins↗
PubMed1993

[Evaluation of drug sensitivity and biochemical properties of coagulase-negative S. aureus strains isolated from clinical specimens].

20-25% of strains isolated in our hospital in 1991 from clinical specimens and identified as S. aureus were coagulase-negative. These strains were characterized in respect of biochemical properties and resistance to antibacterial drugs. It was shown that the investigated group of strains displayed high drug resistance and particularly high percent of strains were resistant to methicillin (60%). 100% strains were resistant to penicillin and tetracyclines and most of them were resistant to aminocyclitol antibiotics. Coagulase-negative strains, in comparison with coagulase-positive, less frequently produced hemolysins and more frequently staphylokinase.

Coagulase↗
PubMed1993

[Bacteriophages of serologic group A converting synthesis of staphylokinase and beta toxin in S. aureus].

The properties of the eight S. aureus bacteriophages of the serogroup A converting staphylokinase production were investigated. Three of them were able to a double conversion: production of the staphylokinase and inhibition of beta toxin synthesis. All of the investigated bacteriophages were classified as the I morphological group of the Styloviridae on the basis of the electron microscope analysis. The size of capsids of the examined bacteriophages was 77 +/- 2.8 nm x 43.1 +/- 1.9 nm and the tail length was 272.7 +/- 12.7 nm. Most of them (6 bacteriophages) had the tail terminated in the basal plate. The lytic properties of the investigated bacteriophages were not identical. Seven of them showed features of the III and one of the V (miscellaneous) lytic group.

Bacterial Toxins↗
PubMed1993

[Increase of pathogenicity of Staphylococcus aureus strains caused by lysogenic conversion by phages of serologic group F].

The substantial influence of presence of the double converting prophages of the serological group F on the decrease of intensity of human leukocytes stimulation with lysogenic cells of S. aureus was determined. The end values of chemiluminescence in the six experimental systems containing lysogenic bacteria were only from 15.4 to 37.2% of the value in the control sample. The end values of the intercellular killing of the two lysogenic variants were twofold lower than in controls. Third of the investigated variants was completely resistant to intracellular killing in the applied system, and revealed 27% of growth stimulation.

Lysogeny↗
PubMed1993

[Production of staphylokinase and hemolysin by coagulase-negative staphylococcus].

The ability to staphylokinase production by the representative of the six of fifteen investigated species of staphylococci was detected: S. epidermidis, S. lentus, S. sciuri, S. lugdunensis, S. xylosus and S. hominis. The frequency of occurrence of this feature was different among the investigated species. Relatively, the least frequently this feature was observed with S. epidermis (2.3%) and S. xylosus (8.3%) strains. This property most frequently occurred among S. lentus--all the examined strains of this species produced staphylokinase. The hemolysins synthesis was shown among 13 of 15 investigated coagulase-negative species of staphylococci. The only two species of the examined representatives did not produce any hemolysin: S. hyicus and S. schleiferi. Complete correlation between staphylokinase synthesis and the absence of beta-hemolysin production was observed among strains: S. lugdunensis and S. lentus as with the lysogenic S. aureus strains with the double converting phages.

Coagulase↗
PubMed1989

[Bacteriophage conversion as a factor modifying the intensity of phagocytosis of Staphylococcus aureus by human leukocytes].

Staphylococcus aureus NCTC 8325-4 and its eight variants lysogenized with phages responsible for the synthesis of staphylococcal staphylokinase were used for the study. Influence of phage conversion of S. aureus on its interaction with human leucocytes and influence of prophage on strain susceptibility to intracellular killing by human granulocytes without opsonins were evaluated. It was found that lysogenization of the strain with the bacteriophages decreased in each case reactivity of human leucocytes for staphylococcal strain what was expressed by lower bioluminescence values and by lower percentage of intracellular killing of bacterial cells carrying prophage.

Culture Media↗
PubMed1987

Location of the coagulase gene in Staphylococcus aureus.

The localization of the coagulase gene in Staphylococcus aureus JM 750 strain was investigated. S. aureus JM 750 strain in contrast to other S. aureus strains shows instability of coagulase production. This strain contains the 23.5 kb penicillinase plasmid, determining beta-lactamase synthesis and resistance to heavy metal salts, and a larger plasmid greater than 100 kb in size, which was detectable only in coagulase positive variants. The results suggest the unparalleled, extrachromosomal localization of the coagulase gene in S. aureus JM 750 strain.

Cloning, Molecular↗
PubMed1987

The role of plasmids in opsonin-independent Staphylococcus aureus-leukocyte interactions.

The opsonin-independent phagocytic and bactericidal activity of human polymorphonuclear leukocytes stimulated by two Staphylococcus aureus strains and their variants with differing plasmid patterns was investigated. Interactions between staphylococci and phagocytes were evaluated by chemiluminescence and intracellular killing tests. The results obtained indicate that the presence or absence of certain plasmids can modify staphylococcal phagocytosis and their susceptibility to intracellular killing. Pretreatment of the strains investigated with subinhibitory concentrations of mezlocillin and ofloxacin (10% MIC) influenced these parameters, too.

Humans↗
PubMed1986

Translocation of the chloramphenicol-resistance determinant in Staphylococcus aureus.

pC658: a plasmid determining resistance to chloramphenicol in the hospital strain of Staphylococcus aureus JM658 was transduced after irradiation of phage lysate with high doses of UV. The localization of determinants causing resistance to chloramphenicol in the obtained transductants was investigated by modified Arber's method and variants resistant to chloramphenicol, but suspected of absence of chloramphenicolase plasmid were selected. Additionally the absence of plasmid DNA was demonstrated in the selected strains. The possibility of plasmid and chromosomal localization of the same gene indicates its translocable nature. The obtained results suggests transposomal character of the genes determining resistance to chloramphenicol in the pC658 plasmid, occurring in the hospital strain of S. aureus.

Chloramphenicol↗
PubMed1985

Chromosomal localization of resistance to fosfomycin and aminocyclitol antibiotics in hospital strains of Staphylococcus aureus.

The chromosomal localization of fosfomycin resistance genes in three hospital Staphylococcus aureus strains and in the standard strain NCTC 8507 was shown. Moreover, the chromosomal locus of the gene determining resistance to three aminocyclitol antibiotics: gentamycin, kanamycin and tobramycin in the one of hospital strains was determined. The possibility of transducing this resistance and the absence of plasmid DNA in the obtained transductants, suggest transposomal nature of the gene determining gentamycin, kanamycin and tobramycin resistance in the investigated strain.

Anti-Bacterial Agents↗