Chapter 23
Staphylococcal Gastroenteritis
The staphylococcal food-poisoning or food-intoxication syndrome was first studied in 1894 by
J. Denys and later in 1914 by M.A. Barber, who produced in himself the signs and symptoms of the
disease by consuming milk that had been contaminated with a culture of Staphylococcus aureus. The
capacity of some strains of S. aureus to produce food poisoning was proved conclusively in 1930
by Dack et al.
28 who showed that the symptoms could be produced by feeding culture filtrates of
S. aureus. Although some authors refer to food-associated illness of this type as food intoxication
rather than food poisoning, the designation gastroenteritis obviates the need to indicate whether the
illness is an intoxication or an infection.
Staphylococcal gastroenteritis is caused by the ingestion of food that contains one or more enterotoxins, which are produced only by some staphylococcal species and strains. Although enterotoxin
production is believed generally to be associated with S. aureus strains that produce coagulase and
thermonuclease (TNase), many species of Staphylococcus that produce neither coagulase nor TNase
are known to produce enterotoxins.
An extensive literature exists on staphylococci and the food-poisoning syndrome, much of which
goes beyond the scope of this chapter.
SPECIES OF CONCERN IN FOODS
The genus Staphylococcus includes over 30 species, and those of real and potential interest in foods
are listed in Table 23–1. Of the 18 species and subspecies noted in the table, only 6 are coagulase
positive, and they generally produce thermostable nuclease (TNase). Ten of the coagulase-negative
species have been shown to produce enterotoxins, and they do not produce nuclease, or those that
do, produce a thermolabile form. The coagulase-negative enterotoxigenic strains are not consistent
in their production of hemolysins or their fermentation of mannitol. The long-standing practice of
examining foods for coagulase-positive staphylococci as the strains of importance has undoubtedly
led to underestimations of the prevalence of enterotoxin producers.
The relationship between TNase and coagulase production in staphylococci is discussed in Chapter
11. It is common to assume that TNase and coagulase-positive strains are the only staphylococci that
warrant further investigations when found in foods, but the existence of both TNase and coagulasenegative enterotoxin-producing strains has been known for some time.
Among coagulase-positive species, S. intermedius is well known as an enterotoxin producer. This
species is found in the nasal passages and on the skin of carnivores and horses, but rarely in humans.
545
Staphylococcal Gastroenteritis
The staphylococcal food-poisoning or food-intoxication syndrome was first studied in 1894 by
J. Denys and later in 1914 by M.A. Barber, who produced in himself the signs and symptoms of the
disease by consuming milk that had been contaminated with a culture of Staphylococcus aureus. The
capacity of some strains of S. aureus to produce food poisoning was proved conclusively in 1930
by Dack et al.
28 who showed that the symptoms could be produced by feeding culture filtrates of
S. aureus. Although some authors refer to food-associated illness of this type as food intoxication
rather than food poisoning, the designation gastroenteritis obviates the need to indicate whether the
illness is an intoxication or an infection.
Staphylococcal gastroenteritis is caused by the ingestion of food that contains one or more enterotoxins, which are produced only by some staphylococcal species and strains. Although enterotoxin
production is believed generally to be associated with S. aureus strains that produce coagulase and
thermonuclease (TNase), many species of Staphylococcus that produce neither coagulase nor TNase
are known to produce enterotoxins.
An extensive literature exists on staphylococci and the food-poisoning syndrome, much of which
goes beyond the scope of this chapter.
SPECIES OF CONCERN IN FOODS
The genus Staphylococcus includes over 30 species, and those of real and potential interest in foods
are listed in Table 23–1. Of the 18 species and subspecies noted in the table, only 6 are coagulase
positive, and they generally produce thermostable nuclease (TNase). Ten of the coagulase-negative
species have been shown to produce enterotoxins, and they do not produce nuclease, or those that
do, produce a thermolabile form. The coagulase-negative enterotoxigenic strains are not consistent
in their production of hemolysins or their fermentation of mannitol. The long-standing practice of
examining foods for coagulase-positive staphylococci as the strains of importance has undoubtedly
led to underestimations of the prevalence of enterotoxin producers.
The relationship between TNase and coagulase production in staphylococci is discussed in Chapter
11. It is common to assume that TNase and coagulase-positive strains are the only staphylococci that
warrant further investigations when found in foods, but the existence of both TNase and coagulasenegative enterotoxin-producing strains has been known for some time.
Among coagulase-positive species, S. intermedius is well known as an enterotoxin producer. This
species is found in the nasal passages and on the skin of carnivores and horses, but rarely in humans.
545