Toxic shock syndrome caused by staphylococcus is due to
Correct Answer: Super antigens
Description: Staphylococcal infections Staphylococci are usually found colonising the anterior nares and skin. Some staphylococci produce coagulase, an enzyme that conves fibrinogen to fibrin in rabbit plasma, causing it to clot. Staph. aureus is coagulase-positive, and most other species are coagulase-negative. In modern laboratory practice, however, the identification of Staph. aureus rarely involves the coagulase test. Staph. aureus is the main cause of staphylococcal infections. Staph. intermedius is another coagulase-positive staphylococcus, which causes infection following dog bites. Among coagulase- negative organisms, Staph. epidermidis is the predominant commensal organism of the skin, and can cause severe infections in those with central venous catheters or implanted prosthetic materials. Staph. saprophyticus is pa of the normal vaginal flora and causes urinary tract infections in sexually active young women. Others implicated in human infections include Staph. lugdunensis, Staph. schleiferi, Staph. haemolyticus and Staph. caprae. Coagulase-negative staphylococci are not usually identified to species level. Staphylococci are paicularly dangerous if they gain access to the blood stream, having the potential to disseminate widely . In any patient with staphylococcal bacteraemia, especially injection drug-users, the possibility of endocarditis must be considered . Growth of Staph. aureus in blood cultures should not be dismissed as a 'contaminant' unless all possible underlying sources have been excluded and repeated blood culture is negative. Any evidence of spreading cellulitis indicates the urgent need for an antistaphylococcal antibiotic, such as flucloxacillin (unless there is a likely risk of MRSA). This is paicularly true for mid-facial cellulitis, which can result in cavernous sinus thrombophlebitis. In addition, Staph. aureus can cause severe systemic disease due to the effects of toxin produced at superficial sites in the absence of tissue invasion by bacteria. Skin infections Staphylococcal infections cause ecthyma, folliculitis, furuncles, carbuncles, bullous impetigo and the scalded skin syndrome . They may also be involved in necrotising infections of the skin and subcutaneous tissues . Wound infections Many wound infections are caused by staphylococci, which may significantly prolong post-operative hospital stays Prevention involves careful attention to hand hygiene, skin preparation and aseptic technique, and the use of topical and systemic antibiotic prophylaxis. Treatment is by drainage of any abscesses plus adequate dosage of antistaphylococcal antibiotics, done early, paicularly if prosthetic implants have been inseed. Cannula-related infection Staphylococcal infection associated with cannula sepsis and thrombophlebitis is an impoant and common reason for morbidity following hospital admission. The Visual Infusion Phlebitis (VIP) score aids cannula evaluation . Ref Harrison20th edition pg 1077
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