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Biomedical subjects

F S Fluer

Publications and source records attributed to F S Fluer.

At least 37 records · Page 2Linked to original sources

Highly sensitive determination of Bacillus cereus exo - enterotoxin using the method of aggregate haemagglutination.

The possibility has been demonstrated of using the method of aggregate-haemagglutination for the detection of B. cereus exo-enterotoxin in both food products and culture media. It has been established that 0.004 mug/ml of enterotoxin can be detected by this method. The applied antisera to B. cereus enterotoxin did not yield cross reactions with enterotoxins produced by E. coli, Cl. perfringens, St. aureus, V. cholerae or Sh. dysenteriae.

Animals↗

[Obtaining purified staphylococcal enterotoxin type B].

The authors elaborated a method of purification of staphylococcus enterotoxin, type B, consisting of three stages: the first stage--lyophilization and dialysis of the culture fluid against distilled water for 36 hours, the second stage--precipitation of dialyzed preparation with 2 volumes of ethanol at --15 degrees C, and the third stage--gel-chromatography of the enterotoxin preparation precipitated with alcohol on a column with Sephadex G-100 in a 0.015 M solution of NaCl (pH 7.0). Preparation isolated by the mentioned method possessed enterotoxic activity in a dose of 0.015 mg of protein per 1 kg of cat weight; by antigenic composition it represented a two-component system. In immunization of rabbits with a purified enterotoxin preparation an antiserum with the prevalence of antibodies to enterotoxin, type B, was obtained.

Enterotoxins↗

[Occurrence of Staphylococcus aureus enterotoxigenic strains isolated from pregnant women with pathology].

137 S. aureus strains, isolated from the larynx of pregnant women in cases of pathology, were studied for the formation of staphylococcal enterotoxins of types A and B (SEA and SEB) by the indirect hemagglutination test. The study revealed that SEA was produced by 35.0% and SEB, by 56.6% of the strains under study. The proportion of SEA and SEB producers among staphylococci isolated from mothers and children was, respectively, 18.4% and 20.0%, 89.41% and 67.5%. The number of enterotoxigenic staphylococci in the upper respiratory tract of newborn infants and mothers practically coincided with that in mothers. The occurrence of SEA- and SEB-producing enterotoxigenic strains in the medical personnel was 25.5% and 62.7% respectively.

Adult↗

[Status of interferon in genital infections].

The interferon status test characterizes the interferon (IFN) system function and the functional activity of IFN-producing cytokine cells. In contrast to the routine method, we used fetal calf (FCS) and autologous sera for evaluating the patients' leukocyte capacity to produce IFN-alpha and IFN-gamma. Blood samples from 30 women with genital infections caused by herpes simplex virus, cytomegalovirus, Chlamydia, and Ureaplasma were tested. Autologous sera of 40% patients inhibited and of 6.6% patients stimulated the production of IFN-gamma in comparison with FCS. All the data are statistically reliable. 20.3% autologous sera contained acid-labile IFN-alpha. These results can be used for more effective immunocorrective therapy.

Animals↗

[Enzyme immunoassay system for detection of staphylococcal enterotoxin, type C].

An enzyme immunoassay (EIA) system for detection of staphylococcal enterotoxin, type C, has been developed. The sensitivity of the system is 1 ng/ml. The optimum EIA parameters have been worked out. The absence of false positive results with heterologous toxins confirms the specificity of the assay system. The possibility of the detection of staphylococcal enterotoxin, type C, in staphylococci isolated from different sources has been shown.

Enterotoxins↗

[Isolation rate of enterotoxigenic staphylococci in patients with sepsis, pneumonia and burns].

The occurrence of Staphylococcus aureus strains producing enterotoxins of types SEA and SEB, which isolated from patients of different profile and caused the infectious process accompanied by pronounced intoxication without vomiting and enteric disturbances, was determined by means of the indirect hemagglutination test. The collection included 28 strains isolated in sepsis, 38 strains isolated in pneumonia, 57 strains isolated from patients with burns and 23, from the hands and nasopharynx of the medical staff. Among the staphylococcal strains isolated in sepsis, 75.6% synthesized SEA and 5.4%, SEB. The occurrence of SEA- and SEB-positive strains isolated in pneumonia was, respectively, 42.1% and 2.6%. From patients with burns SEA-positive staphylococci were mainly isolated (92.9%). Only 3% of the cultures isolated in wound infections produced SEA. From the medical staff, 13.4% of SEA-positive strains and 17.3% of SEB-positive strains were isolated. The data obtained from this study indicate the expediency of the determination of the enterotoxigenic properties of S. aureus clinical isolates in medical institutions for prophylactic measures with a view to the prevention of the spread of pathogenic clones.

Burns↗

[Detection of the genes of pyrogenic toxins of superantigens in clinical isolates of methicillin resistant Staphylococcus aureus].

The content of methicillin resistant S. aureus (MRSA) genes, coding the synthesis of staphylococcal enterotoxins A, B, C (sea, seb, sec) and the toxin of the toxic shock syndrome (tst-H) which was classified with pyrogenic toxins of superantigens (PTSAgs), was studied with the use of PCR amplification. The study revealed the specific features of the content of genes sea and sec, detected in epidemic strains, identified earlier and found to circulate in Russian hospitals. Among the isolates, genetically related to international epidemic strain EMRSA-1, isolates containing no gene sea were detected, while among the isolates genetically related to strain EMRSA-2, isolates containing not only gene sea, but also gene sec were detected, which was indicative of the tendence of this epidemic strain in the direction of further acquisition of pathogenicity genes. As revealed in further studies, among the cultures obtained in bacteriemia, 88% contained gene sea. Two out of three isolates obtained from patients with the symptoms of toxic shock also contained this gene. The differences in the content of genes PTSAgs (sea, seb, sec and tst-H) could serve as a genetic criterium for the differention of isolates circulating in a hospital, as well as for a more complete characterization of the epidemic strains MRSA. The determination of the given genetic markers in genetic strains in circulating strains will make it possible to prognosticate the structure, severity and outcomes of hospital infections. The conditions of PCR amplification for the determination of genes sea, seb, sec and tst-H, as well as multiplex PCR for the determination of genes sea and seb, were developed.

Anti-Bacterial Agents↗

[Detection rate of enterotoxigenic Staphylococcus aureus isolated from children with intestinal disbacteriosis].

Detection rate of enterotoxigenic Staphylococcus aureus isolated from faeces of 62 children aged from 3 months old to 7 years old with intestinal dysbacteriosis was studied by indirect hemagglutination assay and enzume immunoassay. It was shown that strains of S.aureus producing staphylococcal enterotoxin A (SEA) are prevailed (40.3%) in children with disturbances of intestinal microflora while staphylococcal enterotoxin B (SEB)-producing strains were detected in 20.9% of children. Amount of produced enterotoxin varied for SEA from 125 ng/ml to 2000 ng/ml and for SEB--from 125 ng/ml to 250 ng/ml. Inverse dependence of detection rate of enterotoxin-producing strains in faeces on age of children was established. The most number of enterotoxigenic strains of S.aureus was detected in infants. These data point to expediency of determination of enterotoxin-producing ability of S. aureus strains isolated from children with dysbacteriosis as measure of danger of this microorganism for children's health and indication for adequate actions for its elimination.

Age Factors↗

[Determining the levels of staphylococcal enterotoxins types A and B in food products by the immunoenzyme method].

"Sandwich" variant of ELISA was used to identify staphylococcal enterotoxins (SE), types A and B, in S. aureus filtrates inducing food poisoning, in extracts of the lactic acid product for infants "Biphilin" that caused staphylococcal infection, and in foods contaminated with SE in varying concentrations. It has been shown that ELISA used for SE identification in foods permits revealing SE, types A and B, in liquid products in concentrations of 1-2 ng/ml (that is 1000-fold more sensitive, than the immunodiffusion test, 400-800-fold more sensitive than the passive hemagglutination test, and 10-fold more sensitive than the indirect passive hemagglutination test), and in solid products--in concentrations of 5-10 ng/g (after artificial contamination).

Animals↗

[Production of lecithinase by Bacillus thuringiensis].

The activity of lecithaniase was determined in 24 strains of Bacillus thuringiensis on four growth media. The highest accumulation of lecithinase was found on the Hottinger medium containing 0.5% of glucose and 0.56% of sodium bicarbonate. Lecithinase appears at the logarithmic growth phase, and its activity is maximal after 10 hours of growth (at the beginning of the stationary phase). Biosynthesis and accumulation of lecithinase occur at pH 6.0 to 9.0. Lecithinase was purified by salting out with ammonium sulphate (75% saturation). Lecithinase is a thermolabile protein; it is stable within pH range of 3.0 to 9.0 and is resistant to the action of trypsin and 8M urea.

Bacillus thuringiensis↗