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Center for Food Safety & Applied Nutrition Foodborne Pathogenic Microorganisms and Natural Toxins Handbook |
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1. Name of the Organism: Streptococcus spp. |
The genus Streptococcus is comprised of
Gram-positive,
microaerophilic cocci (round), which are not motile and
occur in chains or pairs. The genus is defined by a
combination of antigenic, hemolytic, and physiological
characteristics into Groups A, B, C, D, F, and G. Groups A
and D can be transmitted to humans via food.
Group A: one species with 40 antigenic types (S. pyogenes). Group D: five species (S. faecalis, S. faecium, S. durans, S. avium, and S. bovis). |
| 2. Name of Acute Disease: |
Group A: Cause septic sore throat and
scarlet fever as well
as other pyogenic and septicemic infections.
Group D: May produce a clinical syndrome similar to staphylococcal intoxication. |
| 3. Nature of Illness/Disease: |
Group A: Sore and red throat, pain on swallowing,
tonsilitis, high fever, headache, nausea, vomiting, malaise,
rhinorrhea; occasionally a rash occurs, onset 1-3 days; the
infectious dose is probably quite low (less than 1,000
organisms).
Group D: Diarrhea, abdominal cramps, nausea, vomiting, fever, chills, dizziness in 2-36 hours. Following ingestion of suspect food, the infectious dose is probably high (greater than 107 organisms). |
| 4. Diagnosis of Human Disease: |
Group A: Culturing of nasal and throat swabs, pus, sputum,
blood, suspect food, environmental samples.
Group D: Culturing of stool samples, blood, and suspect food. |
| 5. Associated Foods: |
Group A: Food sources include milk, ice cream, eggs, steamed
lobster, ground ham, potato salad, egg salad, custard, rice
pudding, and shrimp salad. In almost all cases, the
foodstuffs were allowed to stand at room temperature for
several hours between preparation and consumption. Entrance
into the food is the result of poor hygiene, ill food
handlers, or the use of unpasteurized milk.
Group D: Food sources include sausage, evaporated milk, cheese, meat croquettes, meat pie, pudding, raw milk, and pasteurized milk. Entrance into the food chain is due to underprocessing and/or poor and unsanitary food preparation. |
| 6. Relative Frequency of Infection: | Group A infections are low and may occur in any season, whereas Group D infections are variable. |
| 7. Usual Course of Disease and Complications: |
Group A: Streptococcal sore throat is very common,
especially in children. Usually it is successfully treated
with antibiotics. Complications are rare and the fatality
rate is low.
Group D: Diarrheal illness is poorly characterized, but is acute and self-limiting. |
| 8. Target Population: | All individuals are susceptible. No age or race susceptibilities have been found. |
| 9. Analysis of Foods: | Suspect food is examined microbiologically by selective enumeration techniques which can take up to 7 days. Group specificities are determined by Lancefield group-specific antisera. |
| 10. Selected Outbreaks: |
Group A: Outbreaks of septic sore throat and scarlet fever
were numerous before the advent of milk pasteurization.
Salad bars have been suggested as possible sources
of infection. Most current outbreaks have involved complex
foods (i.e., salads) which were infected by a food handler
with septic sore throat. One ill food handler may
subsequently infect hundreds of individuals.
Group D: Outbreaks are not common and are usually the result of preparing, storing, or handling food in an unsanitary manner. |
| For more information on recent outbreaks see the Morbidity and Mortality Weekly Reports from CDC. |
mow@cfsan.fda.gov
January 1992 with periodic updates
