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Streptococcus spp.

S. pyogenes

General characteristics

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, haemolytic, 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 is renamed as the genus Enterococcus .

Disease symptoms

Cause septic sore throat and scarlet fever as well as other pyogenic and septicemic infections.

Sore and red throat, pain on swallowing, tonsillitis, 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).

Diagnosis

Culturing of nasal and throat swabs, pus, sputum, blood, suspect food, and environmental samples.

Associated foods

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 non-pasteurised milk.

Prevention

Raw or undercooked foods and cross-contamination, when cooked material comes into contact with raw produce or contaminated materials (cutting boards), are the main causes of infection. Proper cooking and hygienic food handling thus can prevent Streptococcus infections to a large extend.

Risk populations

All individuals are susceptible. No age or race susceptibilities have been found.

Sources:

The bad bug book : http://www.cfsan.fda.gov/~mow/intro.html