PubMed Health⌕ Search

Biomedical subjects

M S Bergdoll

Publications and source records attributed to M S Bergdoll.

At least 91 records · Page 5Linked to original sources
PubMed1980

Characterization of staphylococci isolated from mastitic cows in Spain.

A total of 57 gram-positive, catalase-positive cocci, considered etiological agents of clinical and subclinical bovine mastitis, were tested for glucose and mannitol fermentation, coagulase and thermonuclease production, sensitivity to lysostaphin, gelatin hydrolysis, lysozyme, phosphatase and egg yolk factor production, hemolytic properties, antibiotic sensitivity, susceptibility to human and bovine phages, and enterotoxin production. All 57 strains were identified as staphylococci. A good correlation was found between 3+ and 4+ coagulase reactions, thermonuclease production, and high sensitivity to lysostaphin. Neither mannitol fermentation nor production of other enzymes appeared to be a specific property of bovine Staphylococcus aureus strains. beta- and delta-hemolysins were more frequently found than alpha-hemolysin. Nearly 40% of the strains were penicillin resistant. Strains were lysed by phage 42E from the human phage set more frequently than by phage 42D, whereas with the bovine set, strains were more sensitive to specific bovine phages. Three strains produced enterotoxin C, and one strain produced enterotoxin D.

Animals↗
PubMed1980

Staphylococcal enterotoxin production in the presence of non-enterotoxigenic staphylococci.

Enterotoxigenic Staphylococcus aureus strains were grown with a non-enterotoxigenic strain in laboratory medium, in milk, and in ham. Differences in pigmentation were used to differentiate the enterotoxigenic strains from the non-enterotoxigenic ones. Enterotoxin was detectable in milk when the colony counts of the non-enterotoxigenic strain were 15 to 20 times greater than those of the enterotoxigenic ones and in ham when the ratio was 60 to 77:1. Enterotoxin was detectable in milk when the enterotoxigenic strains reached counts of 10(7) colony-forming units per ml and in ham when the counts reached 10(8) colony-forming units per ml. It may be necessary in some food poisoning outbreaks to examine many isolates (up to 50 or 60) for enterotoxin production to be able to detect the enterotoxigenic staphylococci.

Animals↗
PubMed1980

Isolation of specific and common antibodies to staphylococcal enterotoxins B, C1, and C2.

Staphylococcal enterotoxins C1 and C2 elicit the production of antibodies in rabbits that give precipitin reactions with both toxins and gel diffusion plates. These enterotoxins also elicit the production of antibodies that are specific for each of the enterotoxins. Enterotoxin B elicits the production of antibodies in some rabbits that react with enterotoxins B, C1, and C2 in gel diffusion plates and in radioimmunoassay. Antibodies specific for enterotoxin B are produced also. Enterotoxin C1 elicits the production of antibodies that cross-react weakly with enterotoxin B, indicating that the antigenic sites involved in the cross-reactions are not identical in the two toxins. The antibodies have been isolated by affinity chromatography.

Animals↗
PubMed1980

Antibodies to staphylococcal enterotoxin in laboratory personnel.

Eighty-five percent of laboratory personnel working with staphylococcal enterotoxin had antibodies to enterotoxin in their sera, whereas only 23% of the control group had antibodies specific for enterotoxin. Two persons who carried enterotoxin B-producing staphylococci in their noses, throats, or both, had antibodies to enterotoxin B in their sera.

Antibodies, Bacterial↗
PubMed1979

Purification and some physicochemical properties of staphylococcal enterotoxin D.

A method was developed for the isolation of staphylococcal enterotoxin D in highly purified form from cultures of Staphylococcus aureus strain 1151m. The method involves removal of the toxin from the culture supernatant fluid with the ion-exchange resin CG-50 followed by chromatography on carboxymethylcellulose (twice) and by gel filtration on Sephadex G-75 (twice). The purified toxin is homogeneous by polyacrylamide gel and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and double gel diffusion tests. It is a simple, colorless, antigenic protein with an isoelectric point of 7.4 as determined by isoelectric focusing. Its molecular weight was determined to be 27 300 +/- 700 by molecular sieve chromatography on Sephadex G-100 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its serological activity is stable over a wide range of pH values (1.2--10.7). The enterotoxin consists of 236 amino acid residues and contains no free sulfhydryl groups. End-group analysis showed serine to be the NH2-terminal amino acid and lysine to be the COOH-terminal amino acid.

Amino Acids↗
PubMed1979

Enterotoxin production by Staphylococcus aureus strains isolated from cases of chronic osteomyelitis.

Of 264 Staphylococcus aureus strains selected at random from 3,978 strains isolated from chronic osteomyelitis patients, 79 were found to produce enterotoxin. A majority of the strains (65%) were nontypable by phages belonging to the international phage set for human strain typing. The significance of these strains and their circulation among the population is discussed, especially from the standpoint of their possible role in the development of osteomyelitis.

Bacteriophage Typing↗
PubMed1978

Detection of staphylococcal enterotoxins A, B, C, D, and E in foods by radioimnunoassay, using staphyloccal cells containing protein A as immunoadsorbent.

A sensitive radioimmunoassay utilizing Staphylococcus aureus cells containing protein A as a coprecipitant was developed for the detection and quantitation of staphylococcal enterotoxins A, B, C, D, and E in a variety of foods. The enterotoxins were extracted from the foods by a simple and rapid procedure. The sensitivity of the assay is 1.0 ng or less of enterotoxin per g of food.

Bacterial Toxins↗
PubMed1978

Molar growth yields and enterotoxin B production of Staphylococcus aureus S-6 with amino acids as energy sources.

Staphylococcus aureus S-6 was able to utilize glutamate, proline, histidine, aspartate, alanine, threonine, serine, or glycine as a major energy source, when these were added singly at a concentration of 2.5 g/liter to a base medium containing salts, vitamins, and 30 mg of each of 18 amino acids per liter. Molar growth yields (Y) for each of the eight amino acids were determined in aerobic batch cultures. Except with aspartate and serine, all molar growth yields decreased with increasing concentration of the energy source, whether or not it was present in excess. The average molar growth yields for both aspartate and serine were Y = 35 g/mol. The highest Y values obtained with the other amino acids were 79, 78, 56, 46, 58, and 21 g/mol for glutamate, proline, histidine, alanine, threonine, and glycine, respectively. Histidine was not utilized as an energy source at concentrations of less than 2 mM. Enterotoxin yields (mg of toxin per g [dry wt] of cells) higher than in the basal medium were obtained when proline, histidine, alanine, serine, and glycine were the major energy sources. When proline and alanine were the major energy sources, enterotoxin yields were not affected by the concentration, whereas toxin yields were reduced at high concentrations of the other six amino acids. The highest cell yields and Y values were obtained with glutamate, but its utilization as an energy source markedly reduced enterotoxin yields.

Amino Acids↗
PubMed1978

Effect of minerals on staphylococcal enterotoxin B production.

Raising the magnesium level from 0.4 to 1.5 mM in a medium containing only amino acids (2.08%), salts, and vitamins increased enterotoxin B production by Staphylococcus aureus S-6 by about 80%. The level of phosphates in the medium was lowered to one-tenth (to 2.87 mM) the original amount without adversely affecting growth and enterotoxin production. The optimum level of potassium was between 15 and 45 mM. Ammonium salts were not essential in the amino acid medium. Sufficient quantities of trace metals were already present. Revising the salt mixture according to the information obtained resulted in a doubling of the enterotoxin B production.

Enterotoxins↗
PubMed1978

Isolation of specific and common antibodies to staphylococcal enterotoxins A and E by affinity chromatography.

Specific and common antibodies to staphylococcal enterotoxins A and E (SEA and SEE) were isolated from anti-SEA and anti-SEE antisera by affinity chromatography. Anti-SEA and anti-SEE antisera were passed through a column with the cross-reacting enterotoxin coupled to a CNBr-activated Sepharose 4B matrix. Specifically bound common antibodies were eluted with NaSCN. The isolated specific antibodies reacted only with the homologous enterotoxin, whereas the common antibodies gave a reaction of identify with both enterotoxins in double gel diffusion plates. The common antibodies had a higher titer against SEE than against SEA. The significance of the isolation of antibodies common to two separate protein molecules is discussed.

Animals↗
PubMed1974

Detection of staphylococcal enterotoxin in foods.

A short procedure for the extraction of staphylococcal enterotoxins from food materials has been developed. The procedure involves extraction of the food at pH 4.5, centrifugation, extraction of the supernatant with CHCl(3) (pH 7.5), extraction of the enterotoxin from the water layer with CG-50 ion exchange resin (pH 5.4 to 5.9), and treatment of the eluate with agar and concentration with Carbowax 20-M. The concentrate was extracted with CHCl(3), and the water layer was lyophilized. The dried material was dissolved in a 1% trypsin solution and placed on microslides, which were incubated 24 h at 37 C. The time required for enterotoxin analysis was 3 days with microslides and 1 day with the reversed passive hemagglutination technique.

Chemical Precipitation↗
PubMed1974

Staphylococcal enterotoxin synthesis during the exponential, transitional, and stationary growth phases.

Small inocula (1 to 10 colony-forming units per ml of broth) of Staphylococcus aureus strains S-6, S-6R, and FRI-100 were employed to study growth and enterotoxin synthesis in 4% protein hydrolysate powder broths. For each strain, the exponential growth phase ended once the population approached 10(9) to 2 x 10(9) colony-forming units per ml. By that time, the concentrations of enterotoxins A and B reached the minimal level (1 to 2 mug/ml) at which the single gel diffusion tube method becomes applicable. By microslides and reverse passive hemagglutination, enterotoxins A and B were found to be synthesized during the exponential growth phase, but at different exponential rates.

Culture Media↗
PubMed1974

Scanning density gradient isoelectric focusing of Staphylococcus aureus enterotoxins B and C.

Purified Staphylococcus aureus enterotoxins B and C(1), the causative agents of staphylococcal food poisoning, were resolved into several components by scanning isoelectric focusing in sucrose density gradients in the absence and presence of 6 M urea and 5 mM dithiothreitol. The observed heterogeneity persisted in the denaturing medium, which suggests that the primary structure of protein enterotoxins B and C(1) may be partly responsible for the isoelectric point differences of the various forms. To our knowledge, the scanning isoelectric focusing patterns of staphylococcal enterotoxins B and C(1) are reported for the first time.

Centrifugation, Density Gradient↗