Severity or extent of infection		Recommended therapy		Comments
Soft tissue infection
Mild (duration of treatment is one to two weeks)		Dicloxacillin 500 mg orally four times per day		Oral agent of choice for MSSA
		Cephalexin (Keflex) 500 mg orally four times per day		For penicillin-allergic patients, except those with immediate hypersensitivity reactions
		Amoxicillin/clavulanate (Augmentin) 875/125 mg orally twice per day		Good option for polymicrobial infection
		Clindamycin (Cleocin) 300 to 450 mg orally three times per day		Potential cross-resistance and emergence of resistance in erythromycin-resistant Staphylococcus aureus; inducible resistance in MRSA
		Doxycycline (Vibramycin) 100 mg orally twice per day or Sulfamethoxazole/trimethoprim (Bactrim) 160/800 mg orally twice per day		Effective for MRSA
Moderate (duration of treatment is two to four weeks, depending on response; administer orally or parenterally followed by orally)
	Risk factors for polymicrobial infection absent*	Nafcillin 1 to 2 g IV every four hours		Parenteral drug of choice for MSSA
		Cefazolin 1 to 2 g IV every eight hours		For penicillin-allergic patients
		Vancomycin 30 mg per kg IV twice per day		Parenteral drug of choice for MRSA
	Risk factors for polymicrobial infection present*	Ampicillin/sulbactam (Unasyn) 3 g IV four times per day		—
		Ceftriaxone (Rocephin) 1 to 2 g IV once per day plus clindamycin 600 to 900 mg IV or orally three times per day or metronidazole (Flagyl) 500 mg IV or orally three times per day		—
			or
		Levofloxacin (Levaquin) 500 mg IV or orally once per day plus clindamycin 600 to 900 mg IV or orally three times per day
		Moxifloxacin (Avelox) 400 mg IV or orally once per day		—
		Ertapenem (Invanz) 1 g IV once per day		—
Severe (duration of treatment is two to four weeks, depending on response; administer parenterally, then switch to orally)		Ciprofloxacin (Cipro) 400 mg IV twice per day plus clindamycin 600 to 900 mg IV three times per day		—
		Piperacillin/tazobactam (Zosyn) 3.375 to 4.500 g IV every six to eight hours		—
		Imipenem/cilastatin (Primaxin) 500 mg IV four times per day		—
		Vancomycin 30 mg per kg IV twice per day plus ciprofloxacin 400 mg IV twice per day plus metronidazole 500 mg IV or orally three times per day		Vancomycin is the parenteral drug of choice for MRSA; linezolid (Zyvox) 600 mg IV or orally twice per day or daptomycin (Cubicin) 4 mg per kg IV once per day can also be used for MRSA Use vancomycin for penicillin-allergic patients
		Tigecycline (Tygacil) 100 mg IV loading dose then 50 mg IV twice per day		Should be used when suspected polymicrobial infection, including MRSA
Bone or joint infection
No residual infected tissue		Use the above parenteral or oral antibiotic regimens for two to five days		—
Residual infected tissue only		Use the above parenteral or oral antibiotic regimens for two to four weeks		—
Residual infected viable bone		Initially use the above parenteral antibiotics followed by oral antibiotics for four to six weeks		—
Residual infected dead bone		Initially use the above parenteral antibiotics followed by oral antibiotics for eight to 12 weeks		—