Staphylococcus aureus (including MRSA)

• A Gram-positive coccus that is often found colonising on the skin of the anterior nares, axilla, and perineum. 

• The methicillin (flucloxacillin) resistant version (MRSA) is a particular infection control hazard. 

• S. aureus in general, (MRSA or MSSA) is a common agent of nosocomial infections in hospitals.

• Currently, between 40-50% of healthcare-associated S aureus infections are due to MRSA, but <5% of true community S aureus infections.

Main clinical infections:

• Skin and soft tissue infections (impetigo, cellulitis)

• Surgical ward infections

• Venflon infections

• Intravascular catheter infections (often with bacteraemia). 

• Severe systemic infections in deep foci such as endocarditis, osteomyelitis, myositis, and fasciitis.

MSSA: Usually sensitive to:

• Flucloxacillin

• Co-amoxiclav

• 1^st and 2^nd generation cephalosporins

• Gentamicin

• Erythromycin

• Doxycycline

• Fusidic acid

• Rifampicin

• Clindamycin

• Trimethoprim

• Vancomycin

Seek microbiology advice for synergistic drug combinations in severe infections.

MSSA: Usually resistant to:

• Benzylpenicillin

• Amoxicillin

• Ceftazidime  

MRSA: (multiple-resistant organism): Usually sensitive to:

• Vancomycin (1^st line choice for i.v. therapy)

• Doxycycline (1^st choice for p.o. therapy in less severe infections) 

• Teicoplanin

• Gentamicin (Gentamicin resistance in MRSA is thankfully uncommon in Nottingham.)

• Trimethoprim

• Fusidic acid

• Rifampicin

MRSA: Usually resistant to:

• All beta-lactam antibiotics (e.g. penicillins, flucloxacillin, cephalosporins, co-amoxiclav, imipenem),

• Quinolones (e.g. ciprofloxacin and levofloxacin),

• Macrolides (erythromycin, clarithromycin) 

Page last edited: 30/06/2009

Caution; the antibiotic doses recommended on this website are intended for adult patients with normal renal and liver function unless otherwise stated. Dosing advice for patients with renal impairment is available here.

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