[Clinical aspects of streptococcal and staphylococcal toxinic diseases]

Staphylococcus aureus and Streptococcus pyogenes produce a lot of toxins, some of them responsible for specific diseases. Staphylococcal food poisoning is due to ingestion of enterotoxin containing food. Seven toxins have been isolated so far. Generalized exfoliative syndrome is related to exfoliatin. Young children are particularly affected. The disease consists in a cutaneous exfoliation usually limited with a favourable outcome. The mucus membranes are not involved. The nose or pharynx are the most usual portal of entry. Staphylococcus aureus is not grown from the bullae. Severe extensive forms have been observed particularly in neonates (Ritter's disease). Bullous impetigo is also due to exfoliatin. It consists in the presence of a restricted number of cloudy bullae, from which staphylococcus can be grown. It is a mild disease with a favourable outcome within a few days. Scarlet fever is related to the streptococcal erythrogenic toxins. The classic form of the disease is presently rare. This disease may be related to staphylococcus as a complication of arthritis, osteomyelitis or wound super-infection. Bacteremia is usual. Staphylococcal scarlet fever is not related to exfoliatin as previously believed, but to enterotoxins or TSST-1, so it seems to be an abortive form of toxic shock syndrome. Toxic shock syndrome is defined as a multi organ failure syndrome with a rapid onset, fever, rash followed by desquamation, vomiting and diarrhea, hypotension, conjunctivitis and strawberry tongue. The disease is related to an infection or colonisation with a toxin (TSST-1) producing strain of Staphylococcus aureus. Enterotoxins (mainly C) may be involved. The disease may occur in childhood, sometimes after superinfection of varicella. The mortality is low (5%) and mainly due to ARDS or cardiac problems. Erythrogenic toxins produced by Streptococcus pyogenes are involved in a streptococcal form of toxic shock syndrome with a quite similar presentation. In most cases however, a cutaneous or soft tissue infection is at the origin. Necrotizing fasciitis complicating varicella is a classic cause in children. Bacteremia is often observed. The mortality rate is as high as 60%. The streptococcal strains involved in north america use to produce the toxin erythrogenic A, the european cases seem to be more related to strains secreting the B toxin with a dysregulation of the mechanisms which control the secretion of the toxin. Staphylococcus strains producing the Panton and Valentine leucocidin are responsible for chronic or relapsing furonculosis and above all for a very severe necrotizing pneumonia observed in children and young adults presenting as an acute respiratory distress syndrome with leucopenia, hemoptysis and shock carrying a heavy mortality rate. Besides these specific diseases, staphylococcal and streptococcal toxins may be involved in some syndromes of unknown origin, in which the intervention of superantigens seems very likely. Kawasaki syndrome is among them as strains producing staphylococcal and streptococcal toxins have been grown from patients with Kawasaki syndrome. In the same way, the intervention of toxins is suspected in the determination of sudden infant death syndrome and atopic eczema.