Antimicrobial Therapy for Staphylococcal Infectionsa
| Sensitivity/Resistance of Isolate | Drug of Choice | Alternative(s) | Comments |
|---|---|---|---|
| Parenteral Therapy for Serious Infections | |||
| Sensitive to penicillin | Penicillin G (4 mU q4h) | Nafcillin or oxacillin (2 g q4h), cefazolin (2 g q8h), vancomycin (1 g q12hb) | Fewer than 5% of isolates are sensitive to penicillin. The clinical microbiology laboratory must verify that the strain is not a β-lactamase producer. |
| Sensitive to methicillin | Nafcillin or oxacillin (2 g q4h) | Cefazolin (2 g q8h), vancomycin (15-20 mg/kg q8-12hb) | Pts with penicillin allergy can be treated with a cephalosporin if the allergy does not involve an anaphylactic or accelerated reaction; desensitization to β-lactams may be indicated in selected cases of serious infection when maximal bactericidal activity is needed (e.g., prosthetic-valve endocarditisc). Type A β-lactamase may rapidly hydrolyze cefazolin and reduce its efficacy in endocarditis. Vancomycin is a less effective option. |
| Resistant to methicillin | Vancomycin (15-20 mg/kg q8-12hb), daptomycin (6 mg/kg IV q24hb,d) for bacteremia, endocarditis, and complicated skin infections | Linezolid (600 mg q12h PO or IV), ceftaroline (600 mg IV q12h) | Sensitivity testing is necessary before an alternative drug is selected. For some serious infections, higher doses of daptomycin have been used. Quinupristin/dalfopristin is bactericidal against methicillin-resistant isolates unless the strain is resistant to erythromycin or clindamycin. The efficacy of adjunctive therapy is not well established in many settings. Both linezolid and quinupristin/dalfopristin have had in vitro activity against most VISA and VRSA strains. See footnote for treatment of prosthetic-valve endocarditis.c |
| Resistant to methicillin with intermediate or complete resistance to vancomycine | Daptomycin (6 mg/kg q24hb,d) for bacteremia, endocarditis, and complicated skin infections | Same as for methicillin-resistant strains; check antibiotic susceptibilities or Ceftaroline (600 mg IV q12h) Newer agents include tedizolid (200 mg administered once daily either IV or orally) or dalbavancin (two IV doses: 1000 mg followed in 1 week by 500 mg). Both drugs are approved only for the treatment of skin and soft tissue infections. | Same as for methicillin-resistant strains; check antibiotic susceptibilities. Ceftaroline is used either alone or in combination with daptomycin. |
| Not yet known (i.e., empirical therapy) | Vancomycin (15-20 mg/kg q8-12hb), daptomycin (6 mg/kg q24hb,d) for bacteremia, endocarditis, and complicated skin infections | — | Empirical therapy is given when the susceptibility of the isolate is not known. Vancomycin is recommended for suspected community- or hospital-acquired Staphylococcus aureus infections because of the increased frequency of methicillin-resistant strains in the community. |
| Oral Therapy for Skin and Soft Tissue Infections | |||
| Sensitive to methicillin | Dicloxacillin (500 mg qid), cephalexin (500 mg qid) | Minocycline or doxycycline (100 mg q12hb), TMP-SMX (1 or 2 ds tablets bid), clindamycin (300-450 mg/kg tid), linezolid (600 mg PO q12h), tedizolid (200 mg PO q24h) | It is important to know the antibiotic susceptibility of isolates in the specific geographic region. All drainage should be cultured. |
| Resistant to methicillin | Clindamycin (300-450 mg/kg tid), TMP-SMX (1 or 2 ds tablets bid), minocycline or doxycycline (100 mg q12hb), linezolid (600 mg bid), or tedizolid (200 mg once daily) | Same options as under “Drug of Choice” | It is important to know the antibiotic susceptibility of isolates in the specific geographic region. All drainage should be cultured. |
aRecommended dosages are for adults with normal renal and hepatic function.
bThe dosage must be adjusted for pts with reduced creatinine clearance.
cFor the treatment of prosthetic-valve endocarditis, the addition of gentamicin (1 mg/kg q8h) and rifampin (300 mg PO q8h) is recommended, with adjustment of the gentamicin dosage if the creatinine clearance rate is reduced.
dDaptomycin cannot be used for the treatment of pneumonia.
eVancomycin-resistant S. aureus isolates from clinical infections have been reported.
Abbreviations: ds, double-strength; TMP-SMX, trimethoprim-sulfamethoxazole; VISA, vancomycin-intermediate S. aureus; VRSA, vancomycin-resistant S. aureus.
Source: Modified with permission from FD Lowy: N Engl J Med 339:520, 1998 (© 1998 Massachusetts Medical Society. All rights reserved.); C Liu et al: Clin Infect Dis 52:285, 2011; DL Stevens et al: Clin Infect Dis 59:148, 2014; Med Lett Drugs Ther 56:39, 2014.