Enterotoxin B Synthesis by Replicating and Nonreplicating Cells of
            <i>Staphylococcus aureus</i>

Markus, Z.; Silverman, G. J.

doi:10.1128/jb.97.2.506-512.1969

Cited by 42 publications

(25 citation statements)

References 12 publications

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“…Production of the other extracellular proteins measured, however, were similarly depressed for all nine strains. This suggests a possible difference between the synthesis of enterotoxin A and that of both enterotoxins B and C. Other investigators suggested that the mechanism of synthesis of enterotoxins A and B is different (13,14).…”

Section: Discussionmentioning

confidence: 95%

Production of Staphylococcal Enterotoxins A, B, and C Under Conditions of Controlled pH and Aeration

1973

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The production of enterotoxins A, B, and C by nine strains of Staphylococcus aureus has been studied under controlled conditions in a fermenter. The strain to strain differences between staphylococci producing a specific enterotoxin were very marked. Increasing aeration in shake flasks improved both growth and production of all extracellular proteins measured other than that of enterotoxin C, the yield of which was decreased in one strain at high aeration. Silicone antifoam decreased the production of extracellular proteins, although enterotoxin A production from three strains was much less affected than that of enterotoxins B and C. In a detailed study of three strains, production of enterotoxins A and C was considerably greater in a defined amino acid medium than in a casein hydrolysate medium and was optimal for all three enterotoxins between pH 6.5 and 7.3. Changes in the pH or medium used in the fermenter that led to increased enterotoxin production could generally be correlated with a change in growth pattern, showing an extended transition period from exponential to stationary phase. Three out of five enterotoxin-A producing strains produced significantly more enterotoxin at a controlled pH of 6.5 in the fermenter than in shake-flask cultures. The yields with strain 100 were about five times greater than hitherto reported. Since many foods are buffered at pH 6 to 6.5, some strains may, therefore, produce sufficient enterotoxin A to cause food poisoning, although little or none may be produced when grown under normal testing procedures.

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Section: Discussionmentioning

confidence: 95%

Production of Staphylococcal Enterotoxins A, B, and C Under Conditions of Controlled pH and Aeration

1973

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“…The production of staphylococcal enterotoxin is enhanced by vigorously shaking enterotoxigenic strains during growth (9,11,13,14,17,19). Excessive shaking, while promoting growth, can actually decrease enterotoxin B secretion, however (4).…”

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confidence: 99%

Staphylococcal Enterotoxin B and Nuclease Production Under Controlled Dissolved Oxygen Conditions

Carpenter

Silverman

1974

Applied Microbiology

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Enterotoxin B, nuclease, and total exoprotein production by Staphylococcus aureus strain S-6 was studied in a 0.5-liter fermentor system. While these extracellular products were elaborated over a wide range of aeration rates, maximal production occurred within the very narrow range of 125 to 150 cm3 of air per min. The levels attained at the optimal aeration rate were not increased by maintaining a constant pH, although yield of enterotoxin:cell mass was highest at a constant pH of 7.0. During the growth cycle of the cultures, when aeration rate alone or aeration rate and pH were held constant, the dissolved oxygen (DO) levels, initially set at 100% of saturation, decreased to 5 to 10% 4 to 5 h after inoculation. The oxygen demand of the culture then maintained this level for an additional 4 to 6 h. This interval of low DO was characterized by maximal growth and exoprotein production. When the DO was controlled at a constant value throughout growth (by increasing or decreasing the airflow rate as appropriate), the culture demonstrated different optima for maximal growth and exoprotein production. A constant DO of 100% stimulated growth to extremely high densities, but the accumulation of toxin and nuclease was not observed. On the other hand, maintaining constant DO levels at 50 or 10% raised exoprotein levels higher than those achieved in a culture grown at the optimal aeration rate. Compared to the optimal aeration rate culture, the 10% DO culture yielded 20% more nuclease, 25% more toxin, and 40 to 50% more total exoprotein. These results indicate that it is the DO and not the aeration rate, per se, that is influential in controlling growth, toxin, nuclease, and total exoprotein production.

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“…Pivnick et a2. (1968) observed to similar studies reported in the literature in which geldiffusion tests were used (Kato et , 19^6;McLean et al, 1968;Markus and Silverman, I969;Morse et al, 1969). Salmonella Others…”

Section: A Stock Cultures and Isolation Of Unknownssupporting

confidence: 76%

Rapid methods for determining staphylococcal toxins and Salmonellae associated with poultry products

Fung

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descending order were: (1) tellurite polymyxin egg yolk agar, (2) Baird-Parker's egg-tellurite-glyoine-pyruvate-agar, (3) tellurite glycine agar, (4) tellurite egg yolk agar, and (5) staphylococcus medium No. 110. These studies did not give conclusive indications as to the superiority of any one medium. It should be noted that except for tellurite glycine agar, the media used by Jay (1963) and Crisley et aï. (1965) were different. De Waart et al. (I968) compared the efficiency of Baird-Parker's egg-tellurite-glycine-pyruvate-agar and Chapman's agar in the enumeration of S. aureus in foods. They concluded that the former medium was better, A new medium, phenolphthalein diphosphate agar with polymyxin was found to give results comparable to seven other selective media (staphylo coccus medium Mo. 110, tellurite-polymyxin-egg-yolk agar, Baird-Parker medium, Vogel and Johnson agar, egg yolk-sodium azide-agar, Russian milk-salt-agar, and English milk-saltagar) when tested for the Isolation and enumeration of coagulase-positive staphylococci from foods (Hobbs et , I968). Liquid enrichment media have also been used in conjunction with the solid plating media for greater recovery of staphylo cocci especially when small numbers are involved. Wilson et al. (1959) incubated aliquots of food samples (custard, ham, creamed chicken, and milk) in an enrichment broth (3«7^ brain heart infusion broth, 2.0^ mannitol, and 7.5^ NaCl) for 24-48

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Enterotoxin B Synthesis by Replicating and Nonreplicating Cells of Staphylococcus aureus

Cited by 42 publications

References 12 publications

Production of Staphylococcal Enterotoxins A, B, and C Under Conditions of Controlled pH and Aeration

Production of Staphylococcal Enterotoxins A, B, and C Under Conditions of Controlled pH and Aeration

Staphylococcal Enterotoxin B and Nuclease Production Under Controlled Dissolved Oxygen Conditions

Rapid methods for determining staphylococcal toxins and Salmonellae associated with poultry products

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