Internal medicine journal
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Internal medicine journal · Dec 2005
ReviewEpidemiology, clinical features and management of infections due to community methicillin-resistant Staphylococcus aureus (cMRSA).
Methicillin-resistant Staphylococcus aureus (MRSA) was initially confined to hospitals, but in the late 1970s appeared in the community in the USA, primarily among intravenous drug users. In the 1990s, community MRSA (cMRSA) strains appeared in multiple areas of the world, and spread extensively. Initially, there were problems with the definition of 'community-acquired', which was exacerbated by the fact that if a time-based definition was used without stratification for risk factors, patients with healthcare-associated MRSA would be counted. ⋯ While cMRSA strains are usually susceptible to most non-beta-lactam antimicrobials, there is a lack of clinical trial data indicating which drugs have superior clinical efficacy. DNA fingerprinting methods have become more sophisticated over the last decade, and have determined that cMRSA strains have probably arisen from virulent methicillin-susceptible strains, most likely by horizontal transfer of methicillin-resistance genes from coagulase negative staphylococci to S. aureus on a limited number of occasions, and these clones have spread extensively throughout the world by person-to-person transmission. In Australia, the dominant cMRSA clones are the Western Australia, Oceania and Queensland strains.
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Internal medicine journal · Dec 2005
ReviewRecognition and management of Staphylococcus aureus toxin-mediated disease.
The ubiquitous human pathogen Staphylococcus aureus is capable of producing a formidable range of extracellular toxins that can have significant deleterious effects on the host. Toxic shock syndrome (TSS) results from infection or colonization with a strain of S. aureus that produces staphylococcal enterotoxin(s). The key features of TSS are widespread erythroderma occurring in association with profound hypotension and multiple organ dysfunction. ⋯ Staphylococcal scalded skin syndrome (SSSS) results from colonization or infection with a strain of S. aureus that produces epidermolytic toxin(s). SSSS ranges in severity from trivial focal skin blistering to extensive, life-threatening exfoliation. This review discusses the epidemiology, pathogenesis, diagnosis, and management of TSS, SFD and SSSS.
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Internal medicine journal · Dec 2005
ReviewDiagnosis and management of Staphylococcus aureus bacteraemia.
Staphylococcus aureus bacteraemia (SAB) is common. Around 8000 cases occur per year in Australia, of which 60% are hospital- or healthcare-associated. Risk factors for SAB include injectable drug use, haemodialysis, indwelling vascular catheters and immunosuppression. ⋯ However, vancomycin remains the therapy of choice for SAB due to methicillin-resistant strains. Combination therapy with gentamicin may be useful for the first few days of treatment in selected patients, but otherwise there are few data to support the use of combination regimens in SAB. Newer agents such as linezolid and quinupristin/dalfopristin may have a role in selected patients, especially in SAB due to S. aureus strains with reduced susceptibility to vancomycin.
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Internal medicine journal · Dec 2005
ReviewAntibiotics currently used in the treatment of infections caused by Staphylococcus aureus.
Staphylococcal infections are a common and significant clinical problem in medical practice. Most strains of Staphylococcus aureus are now resistant to penicillin, and methicillin-resistant strains of S. aureus (MRSA) are common in hospitals and are emerging in the community. Penicillinase-resistant penicillins (flucloxacillin, dicloxacillin) remain the antibiotics of choice for the management of serious methicillin-susceptible S. aureus (MSSA) infections, but first generation cephalosporins (cefazolin, cephalothin and cephalexin), clindamycin, lincomycin and erythromycin have important therapeutic roles in less serious MSSA infections such as skin and soft tissue infections or in patients with penicillin hypersensitivity, although cephalosporins are contra-indicated in patients with immediate penicillin hypersensitivity (urticaria, angioedema, bronchospasm or anaphylaxis). ⋯ Nosocomial strains of MRSA are typically multi-resistant (mrMRSA), and mrMRSA strains must always be treated with a combination of two oral antimicrobials, typically rifampicin and fusidic acid, because resistance develops rapidly if they are used as single agents. Most community-acquired strains of MRSA in Australia and New Zealand are non multiresistant (nmMRSA), and lincosamides (clindamycin, lincomycin) or cotrimoxazole are the antibiotics of choice for less serious nmMRSA infections such as skin and soft tissue infections. New antibiotics such as linezolid and quinupristin/dalfopristin have good antistaphylococcal activity but are very expensive and should be reserved for patients who fail on or are intolerant of conventional therapy or who have highly resistant strains such as hVISA (heterogenous vancomycin-intermediate S aureus).