- Discussion: (see MSSA)
- 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 (ie resistant to penicillins and cephalosporins);
- 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;
- osteomyelitis:
- Comparative Severity of Pediatric Osteomyelitis Attributable to Methicillin-Resistant Versus Methicillin-Sensitive Staphylococcus aureus
- 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.
- Association between Staphyloccocus 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
- septra and rifampin (for chronic suppression)
- The bactericidal effects of anti-MRSA agents with rifampicin and sulfamethoxazole-trimethoprim against intracellular phagocytized MRSA
- clindamycin
- inducible resistance (appears sensitive on petri dish but is not)
- D-test: an erythromycin disk is placed near a clindamycin disk on a Kirby-Bauer plate;
- w/ inducible resistance, zone of inhibition around clinda will be flattened in direction of erythromycin disc and will resemble letter D;
- minocycline
- rifampin
- Rifampicin as an adjunct to vancomycin therapy in MRSA septicaemia in burns.
- teicoplanin
- daptomycin
- bacitracin (topical)
- 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 methicillin-resistant Staphylococcus aureus during a Hospital Epidemic.
- Comparison of levofloxacin, alatrofloxacin, and vancomycin for prophylaxis and treatment of experimental foreign-body-associated infection by methicillin-resistant Staphylococcus aureus.
- Teicoplanin alone or combined with rifampin compared with vancomycin for prophylaxis and treatment of experimental foreign body infection by methicillin-resistant Staphylococcus aureaus.
- Necrotizing Fasciitis Caused by methicillin-resistant Staphylococcus aureus Resulting in Death. A report of three cases.
- 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.
No mercy for MRSA: treatment alternatives to vancomycin and linezolid