Staph aureus

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- See: S. epidermidis

- Discussion:
    - is a coagulase positive, gram positive organism;
    - has a strong propensity to invade traumatized tissue;
    - often responsible for toxic shock syndrome and necrotizing fascitis;
           - serious infection that spreads rapidly along fascial planes and is commonly caused by staph or strep pyogenes;
           - anaerobes - especially clostridia and bacteroides can also be the cause;
   - progressive bacterial synergistic infections:
           - may begin as a small lesion that rapidly developes into synergistic gangrene, necessitating amputation;
           - peptostreptococcus and staphylococcus, the 2 organisms most often involved in this disease;
           - organisms act synergistically to produce necrosis and ulceration of both skin and subcutaneous tissues;
   - nasal carriage:
   - antibiotic choices:
           - first generation cephalsporins (cefazolin);
           - penicillinase resistant penecillins
           - second line agents:
                  - vancomycin
                  - erythromycin
                  - clindamycin
                  - IMP

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- Methicillin Resistant Staph Aureus
    - true methicillin resistance involves the production of enzymes which are able to maintain cell-wall integrity during growth and division even when beta lactams
           have inactivated penicillin-binding proteins; 
    - MSRA of are now present in both large and small non-teaching hospitals and in community nursing homes;
           - approximately 15% of all nosocomial staph aureus isolates are methicillin resistant;
           - approximately 75 % of staph. epidermidis strains are resitant and 80% staph haemolyticus strains are resistant; 
    - Panton-Valentine leucocidin: 
           - pore-forming toxin secreted by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) and with the often-lethal necrotizing pneumonia;
           - genes encoding for Panton-Valentine leucocidin may be a primary reason for aggressive prevalance in the community;
           - references:
                   - Necrotizing fasciitis caused by community-associated methicillin-resistant Staphylococcus aureus in Los Angeles. 
                   - Community-acquired methicillin-resistant Staphylococcus aureus carrying Panton-Valentine leukocidin genes: worldwide emergence.
                   - Assoc between S aureus strains carrying gene for Panton-Valentine leukocidin and lethal necrotising pneumonia in immunocompetent patients.
                   - Is Panton-Valentine leukocidin the major virulence determinant in community-associated methicillin-resistant Staphylococcus aureus disease?
                   - Staphylococcus aureus Panton-Valentine Leukocidin Causes Necrotizing Pneumonia

    - treatment:
           - prevention:
                   - the best treatment is prevention:
                   - hospital personel should wash hands after every patient contact; 
                   - ref: The role of MRSA screening in joint-replacement surgery.
           - antibiotic choices:
                   - vancomycin
                   - zyvox 
                          - Linezolid in the Treatment of Implant-related Chronic Osteomyelitis.
                          - Linezolid treatment of prosthetic hip Infections due to methicillin-resistant Staphylococcus aureus (MRSA).
                          - Safety and tolerability of linezolid. 
                   - septra and rifampin (for chronic suppression) 
                   - teicoplanin
                   - daptomycin
                          - Clinical Experience with Daptomycin Treatment of Foot or Ankle Osteomyelitis: A Preliminary Study.
                          - Long-term use of daptomycin for MRSA osteomyelitis and joint infection.
                          - Uncertain efficacy of daptomycin for prosthetic joint infections: a prospective case series.  
                   - bacitracin
                          - Eradication of colonization by methicillin-resistant Staphylococcus aureus by using oral minocycline-rifampin and topical mupirocin. 
                          - Contemporary antimicrobial activity of triple antibiotic ointment: a multiphased study of recent clinical isolates in the United States and Australia.

    - references: 
           - Intramedullary Fixation of Long Bones--Basic Science and Pathology: Orthopedic Experience with MRSA aureus During a Hospital Epidemic.
           - Comparison of levofloxacin, alatrofloxacin, and vancomycin for prophylaxis and treatment of experimental foreign-body-associated infection by MRSA.
           - Teicoplanin alone or combined with rifampin compared with vancomycin for prophylaxis and treatment of experimental foreign body infection by MRSA. 
           - Necrotizing Fasciitis Caused by MRSA Resulting in Death. 
           - Natural history of community-acquired methicillin-resistant Staphylococcus aureus colonization and infection in soldiers.
           - Bactericidal activity of orally available agents against methicillin-resistant Staphylococcus aureus.

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Year Book: Antibiotic Resistance of Biomaterial-Adherent Coagulase-Negative and Coagulase-Positive Staphylococci.

Staphylococcus aureus nasal carriage and infection in patients on hemodialysis. Efficacy of antibiotic prophylaxis.

The efficacy of calcium mupirocin in the eradication of nasal Staphylococcus aureus carriage.

Alteration of staphylococcal flora in cardiac surgery patients receiving antibiotic prophylaxis. 

Impetigo contagiosa III. Comparative efficacy of oral erythromycin and topical mupirocin. 

Alternatives to Vancomycin for the treatment of methicillin-resistant Staphylococcus aureus infections.