Methicillin Resistant Staphylococcus aureus
resistant to all ß-lactam agents, including cephalosporins and carbapenems, although they may be susceptible to the newest class of MRSA-active cephalosporins (e.g, ceftaroline.
mecA gene encoded
Produce Altered Penicillin binding protein (PBP 2a)
Could cause : Hospital acquired or Community acquired infections;
• Strains of MRSA causing healthcare-associated infections are often resistant to other commonly used antimicrobial agents; including erythromycin, clindamycin and fluoroquinolones
• MRSA strains causing community-associated infections are often resistant only to ß-lactam agents, erythromycin and occasionally to fluoroquinolones.
Treatment;
DOC : Vancomycin 15-20mg/Kg body weight
Alternative parenteral agents:
• Teicoplanin
• Daptomycin
• Linezolid
• Quinupristin-dalfopristin
Oral agents:
DOC = Clindamycin
Alternative oral agents:
• Cotrimoxazole,
• Doxycycline,
• Linezolid
VRSA: Vancomycin Resistant Staphylococcus aureus
van A gene mediated
VISA: Vancomycin Intermediate Staphylococcus aureus
increase cell wall thickness can lead to intermediate susceptibility
[ VRSA: MIC for vancomycin: ≥16µg/ml
VISA: MIC for vancomycin: 4-8µg/ml ]
Treatment of VRSA:
• Ceftarolin
• Daptomycin
• Linezolid
• Quinpristin-dalfopristin