Staphylococcus aureusand Streptococcus pyogenes(group A streptococci)
are Gram-positive pathogens capable of producing a variety of bacterial exo-toxins known as superantigens. Superantigens interact with antigen-present-ing cells (APCs) and T cells to induce T cell proliferation and massive
cytokine production, which leads to fever, rash, capillary leak and subse-quent hypotension, the major symptoms of toxic shock syndrome.
Confluent Desquamative Erythemas These eruptions consist of diffuse erythema frequently followed by desquamation. The eruptions caused by group A Streptococcus or Staphylococcus aureus are toxin mediated. Scarlet fever (Chap. 130) usually follows pharyngitis; patients have a facial flush, a "strawberry" tongue, and accentuated petechiae in body folds (Pastia's lines). Kawasaki disease (Chaps. 54 and 319) presents in the pediatric population as fissuring of the lips, a strawberry tongue, conjunctivitis, adenopathy, and sometimes cardiac abnormalities.
Pathogenesis of Fever
Pyrogens The term pyrogen is used to describe any substance that causes fever. Exogenous pyrogens are derived from outside the patient; most are microbial products, microbial toxins, or whole microorganisms. The classic example of an exogenous pyrogen is the lipopolysaccharide (endotoxin) produced by all gramnegative bacteria. Pyrogenic products of gram-positive organisms include the enterotoxins of Staphylococcus aureus and the group A and B streptococcal toxins, also called superantigens.
Streptococcal Toxic Shock Syndrome: Treatment
In light of the possible role of pyrogenic exotoxins or other streptococcal toxins in streptococcal TSS, treatment with clindamycin has been advocated by some authorities (Table 130-3), who argue that, through its direct action on protein synthesis, clindamycin is more effective in rapidly terminating toxin production than penicillin—a cell-wall agent. Support for this view comes from studies of an experimental model of streptococcal myositis, in which mice given clindamycin had a higher rate of survival than those given penicillin.
Other Causes of Vaginal Discharge or Vaginitis
In the ulcerative vaginitis associated with staphylococcal toxic shock syndrome, Staphylococcus aureus should be promptly identified in vaginal fluid by Gram's stain and by culture. In desquamative inflammatory vaginitis, smears of vaginal fluid reveal neutrophils, massive vaginal epithelial-cell exfoliation with increased numbers of parabasal cells, and gram-positive cocci; this syndrome may respond to treatment with 2% clindamycin cream.