Chapter 24
Food Poisoning Caused
by Gram-Positive
Sporeforming Bacteria
At least three Gram-positive sporeforming rods are known to cause bacterial food poisoning:
Clostridium perfringens (welchii), C. botulinum, and Bacillus cereus. The incidence of food poisoning caused by each of these organisms is related to certain specific foods, as is food poisoning in
general.
CLOSTRIDIUM PERFRINGENS FOOD POISONING
The causative organism of this syndrome is a Gram-positive, anaerobic, spore-forming rod, widely
distributed in nature. Based on their ability to produce certain exotoxins, five types are recognized:
types A, B, C, D, and E. The food-poisoning strains belong to type A, as do the classic gas gangrene
strains, but unlike the latter, the food-poisoning strains are generally heat resistant and produce only
traces of alpha toxin. Some type C strains produce enterotoxin and may cause a food-poisoning
syndrome. The classic food-poisoning strains differ from type C strains in not producing beta toxin.
The latter, which have been recovered from enteritis necroticans, are compared to type A heat-sensitive
and heat-resistant strains in Table 24–1. Type A heat-resistant strains produce theta toxin, which is
perfringolysin O (PLO), a thiol-activated hemolysin similar to listeriolysin O (LLO), produced by
Listeria monocytogenes (discussed in Chapter 25). Like LLO, PLO has a molecular weight of 60 kDa,
and it has been sequenced and cloned.
Although C. perfringens has been associated with gastroenteritis since 1895, the first clearcut
demonstration of its etiological status in food poisoning was made by McClung,
79 who investigated
four outbreaks in which chicken was incriminated. The first detailed report of the characteristics of this
food-poisoning syndrome was that of Hobbs et al.
50 in Great Britain. Although the British workers
were more aware of this organism as a cause of food poisoning during the 1940s and 1950s, few
incidents were recorded in the United States prior to 1960. It is clear now that C. perfringens food
poisoning is widespread in the United States and many other countries.
567
Food Poisoning Caused
by Gram-Positive
Sporeforming Bacteria
At least three Gram-positive sporeforming rods are known to cause bacterial food poisoning:
Clostridium perfringens (welchii), C. botulinum, and Bacillus cereus. The incidence of food poisoning caused by each of these organisms is related to certain specific foods, as is food poisoning in
general.
CLOSTRIDIUM PERFRINGENS FOOD POISONING
The causative organism of this syndrome is a Gram-positive, anaerobic, spore-forming rod, widely
distributed in nature. Based on their ability to produce certain exotoxins, five types are recognized:
types A, B, C, D, and E. The food-poisoning strains belong to type A, as do the classic gas gangrene
strains, but unlike the latter, the food-poisoning strains are generally heat resistant and produce only
traces of alpha toxin. Some type C strains produce enterotoxin and may cause a food-poisoning
syndrome. The classic food-poisoning strains differ from type C strains in not producing beta toxin.
The latter, which have been recovered from enteritis necroticans, are compared to type A heat-sensitive
and heat-resistant strains in Table 24–1. Type A heat-resistant strains produce theta toxin, which is
perfringolysin O (PLO), a thiol-activated hemolysin similar to listeriolysin O (LLO), produced by
Listeria monocytogenes (discussed in Chapter 25). Like LLO, PLO has a molecular weight of 60 kDa,
and it has been sequenced and cloned.
Although C. perfringens has been associated with gastroenteritis since 1895, the first clearcut
demonstration of its etiological status in food poisoning was made by McClung,
79 who investigated
four outbreaks in which chicken was incriminated. The first detailed report of the characteristics of this
food-poisoning syndrome was that of Hobbs et al.
50 in Great Britain. Although the British workers
were more aware of this organism as a cause of food poisoning during the 1940s and 1950s, few
incidents were recorded in the United States prior to 1960. It is clear now that C. perfringens food
poisoning is widespread in the United States and many other countries.
567