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Biomedical subjects

B Skalka

Publications and source records attributed to B Skalka.

At least 37 records · Page 2Linked to original sources
PubMed1987

Dynamics of equi-factor antibodies in sera of foals kept on farms with differing histories of Rhodococcus equi pneumonia.

The occurrence of equi-factor antibodies in sera of mares and their foals was studied on two horse breeding farms, one of which (Farm A) had a positive and the other (farm B) a negative history of R. equi infection of foals. The equi-factor neutralization (EFN) and the reverse Elek-Ouchterlony (REO) precipitation were used as assays. On Farm A, 25 mares positive in both tests (EFN+ REO+) and 25 mares negative in both tests (EFN- REO-) was chosen. On Farm B, a group of 25 EFN- REO+ mares and a group of 25 EFN- REO- mares were studied. The first serum samplings in mares were 1 week ante partum and the subsequent samplings in both mares and foals were in the first week after birth and at the end of every month of the foals' age up to 6 months, with further samplings at 8 and 12 months. A higher number of seropositive foals was found on Farm A, but the difference between Farms A and B was not significant. The smallest number, with the lowest titres, was among the foals of EFN- REO+ dams. The number of foals positive in the REO test was higher than in the EFN test. The onset of EFN positivity was found in foals on both farms in the first month of their age, always culminating in the third and fourth months in titres varying between 1:64 and 1:2048, after which time it fell until it disappeared altogether or reached values of 1:4. The results showed the widespread nature of subclinical infection with R. equi on horse farms.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomycetales Infections↗
PubMed1985

Two techniques for detection of antibodies against Corynebacterium (Rhodococcus) equi in horse sera.

Two techniques were developed to detect antibodies against the exosubstance of C. equi called equi-factor. In the first technique serum samples are tested against native equi-factor produced by the growth of C. equi on agar medium. A positive result is manifested by the development of precipitation lines. The second test is based on neutralization of prepurified equi-factor by antibody, resulting in the inhibition of its hemolytic synergism with staphylococcal beta toxin. Sera (125 samples) from horses of different ages, kept in localities with a history of C. equi infections, were examined. The first technique detected 65.6%, and the second 40% of positive cases.

Agglutination Tests↗
PubMed1985

[Hyaluronidase test in the diagnosis of staphylococci].

Using the Streptococcus equi decapsulation test, 879 strains of S. aureus, 212 strains of S. intermedius and 214 coagulase-negative staphylococci were examined for hyaluronidase production; six of the coagulase-negative staphylococci belonged to S. hyicus subsp. hyicus. Positive hyaluronidase production was recorded in all strains of S. aureus and in the strains of S. hyicus subsp. hyicus. No hyaluronidase was produced by 208 coagulase-negative staphylococci and the strains of S. intermedius. The decapsulation test is recommended as a reliable method of the differentiation of S. aureus and S. intermedius.

Hyaluronoglucosaminidase↗
PubMed1985

[Modern scheme for the diagnosis of staphylococci].

A simplified scheme for the subdivision of coagulase-positive staphylococci and another simplified scheme for the diagnostics of coagulase-negative species were worked out. On the basis of the production of staphylokinase, coagulation of human and bovine plasma, acetoin production from glucose, and growth on agar with crystal violet, it is possible to identify S. aureus with its biovars A, B, C1, C2, D, as well as S. intermedius. The coagulase-negative species can be diagnosed according to their sensitivity to novobiocin, nitrate reduction, fermentation of maltose, sucrose, salicin, xylose, trehalose, mannitol and mannose, and haemolytic activity. The proposed diagnostic schemes were verified with success on the collection strains and on the 1305 staphylococci strains isolated largely from the bovine mammary gland, from dogs, man and domestic fowl. In S. aureus strains a close correlation was demonstrated between their biotype characteristics and the host species. A similar correlation was determined for S. intermedius. As to the coagulase-negative species, S. epidermidis, S. hominis and S. haemolyticus were diagnosed most frequently. Both schemes represent a reliable, prompt and technically simple method of the diagnostics of the Staphylococcus microorganisms.

Animals↗
PubMed1983

Selective diagnostic medium for pathogenic Listeria spp.

Pathogenic Listeria serovars produced hemolysis on agars containing 5% rabbit erythrocytes and 10 micrograms of acriflavin, 40 micrograms of nalidixic acid, and 7.5 activity units of equi factor per ml. Apathogenic Listeria innocua was nonhemolytic on this medium.

Corynebacterium↗
PubMed1983

Further observations of Corynebacterium renale as an indicator organism in the detection of the exfoliation-positive strains of Staphylococcus aureus.

Exfoliatin-positive S. aureus strains of known phenotypes were examined for bacteriocin production using S. aureus 209P, C. pseudodiphtheriticum, or C. renale as indicator strains. Strains of the phenotype Bac+ Tox+ had a positive result when the simultaneous method was used, and produced a wide inhibition of the indicator strains, especially of C. renale, if the deferred method was used. The strains of the phenotype Bac- Tox+ were negative upon examination by the simultaneous method, but they caused narrow inhibition zones of the indicator strains to appear with the deferred method, especially with C. renale. S. aureus strains of diverse origin used as controls were in both methods negative with regard to inhibition of indicator strains. C. renale was found to be very suitable for the detection of bacteriocins of the exfoliatin-positive staphylococci, particularly when using the deferred method.

Bacterial Toxins↗
PubMed1983

Hemolytic phenomenons under the cultivation of Listeria innocua.

It was proved that Listeria innocua is able to hemolyze rabbit erythrocytes in blood agars when Oxoid or Difco nutrient agars are used as basic substrate. After 48 h incubation at 37 degrees C and a further 24 h at 4 degrees C the hemolytic effect was clearly expressed. The hot-cold incubation was inevitable. Unlike the hemolytic effect of L. monocytogenes, the hemolytic phenomenon of L. innocua was not enhanced by the equi-factor.

Agar↗
PubMed1983

New possibilities of staphylococcin detection in the exfoliatin-producing strains of staphylococcus aureus.

C. renale was found to be highly sensitive to the effect of bacteriocin produced by the exfoliatin-positive strains of S. aureus. The sensitivity of other indicator organisms used was determined through descending series of C. pseudodiphtheriticum, C. diphtheriae, S. aureus strains Oxford 209P, UT 0017, and Wood 46. Strains of C. pyogenes only produced contradictory results which made any satisfactory interpretation impossible. A modification of the simultaneous bacteriocin-detection method of exfoliatin-positive S. aureus strains, which use suspension of an indicator strain in nutrient agar to obtain lawn homogeneity, has been employed. The use of the modified method together with C. renale to serve as the indicator strain represents a rapid and reliable test suitable for routine diagnostics.

Agar↗
PubMed1982

Routine test for in vitro differentiation of pathogenic and apathogenic Listeria monocytogenes strains.

The exosubstance of Rhodococcus equi in a prepurified form strongly enhanced the hemolytic effect of certain strains of Listeria monocytogenes. The strains which produced positive synergic hemolysis with this exosubstance were also pathogenic for guinea pigs and white mice. The other strains, which remained nonhemolytic in the presence of the R. equi. exosubstance, were apathogenic for those animals. A routine test was devised for the in vitro determination of the pathogenicity of L. monocytogenes strains.

Animals↗
PubMed1982

Hemolytic properties of exosubstance of serovar 5 Listeria monocytogenes compared with beta toxin of Staphylococcus aureus.

Hemolytic exosubstance of serovar 5 Listeria monocytogenes, tested in native and pre-purified forms, produced identical interactions with exosubstances of certain bacterial species to those of Staphylococcus aureus beta toxin on agars with ovine, rabbit, human and equine erythrocytes. In the same way like the staphylococcal beta toxin, it enhanced hemolysis of other L. monocytogenes serovars, though only slightly and after a longer time of incubation. With the hemolysin of Corynebacterium pyogenes it produced a characteristic sickle-shape hemolysis on sheep blood agars. The listerial exosubstance observed had a direct hemolytic effect on sheep, rabbit, human and horse erythrocytes in both agar and tube tests. In addition to the direct hemolysis in tube tests it produced the hot-cold type hemolysis in titres considerably exceeding those of direct action on sheep erythrocytes. The staphylococcal beta toxin macroscopically altered only sheep erythrocytes, with which it produced hot-cold hemolysis in tube tests, and gave no visible reaction with other erythrocytes used either in agar or tube tests. A comparison of both exosubstances showed that their hemolytic activity was strongly enhanced by the exosubstance of Rhodococcus equi on sheep, rabbit and human blood agars, though only the hemolysin of serovar 5 L. monocytogenes had its hemolysis enhanced on horse erythrocytes also.

Animals↗