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Community-Associated Methicillin-Resistant Staphylococcus Aureus (CA-MRSA)
From WikEM
Contents
Background
- Two kinds of MRSA:
- Hospital acquired-MRSA (HA-MRSA)
- Multi-drug resistant, most commonly seen in ventilator associated pneumonia, post operative infections, and catheter associated infections
- Community acquired-MRSA (CA-MRSA)
- Tends to be resistant to beta-lactams, most commonly seen in Skin and Soft Tissue Infections and rarely in necrotizing pneumonia
- Hospital acquired-MRSA (HA-MRSA)
Risk Factors
- Multiple skin sites
- Recurrent infection
- Close contact of person with Hx of MRSA
- Infection showing early necrosis
Management
- Antibiotics
- Cephalexin + Bactrim DS
- Estimated 95-100% sensitivity of CA-MRSA
- Clindamycin
- Approximately 50% sensitivity to CA-MRSA
- Inducible resistance by erythromycin in laboratory, unclear significance
- Doxycycline
- Contraindicated in pregnant females and children due to deposition in teeth and bones
- Vancomycin IV if severe infection/sepsis
- Linezolid
- I&D + Bactrim DS if abscess
- Cephalexin + Bactrim DS
Antibiotic Sensitivities[1]
| Category | Antibiotic | CA-MRSA |
| Penicillins | Penicillin G | R |
| Penicillin V | R | |
| Methicillin | R | |
| Nafcillin/Oxacillin | R | |
| Cloxacillin/Diclox. | R | |
| Amino-Penicillins | AMP/Amox | R |
| Amox-Clav | R | |
| AMP-Sulb | R | |
| Anti-Pseudomonal Penicillins | Ticarcillin | R |
| Ticar-Clav | R | |
| Pip-Tazo | R | |
| Piperacillin | R | |
| Carbapenems | Doripenem | R |
| Ertapenem | R | |
| Imipenem | R | |
| Meropenem | R | |
| Aztreonam | R | |
| Fluroquinolones | Ciprofloxacin | I |
| Ofloxacin | X1 | |
| Pefloxacin | X1 | |
| Levofloxacin | I | |
| Moxifloxacin | I | |
| Gemifloxacin | I | |
| Gatifloxacin | I | |
| 1st G Cephalo | Cefazolin | R |
| 2nd G. Cephalo | Cefotetan | R |
| Cefoxitin | R | |
| Cefuroxime | R | |
| 3rd/4th G. Cephalo | Cefotaxime | R |
| Cefizoxime | R | |
| CefTRIAXone | R | |
| Ceftaroline | S | |
| CefTAZidime | R | |
| Cefepime | R | |
| Oral 1st G. Cephalo | Cefadroxil | R |
| Cephalexin | R | |
| Oral 2nd G. Cephalo | Cefaclor/Loracarbef | R |
| Cefproxil | R | |
| Cefuroxime axetil | R | |
| Oral 3rd G. Cephalo | Cefixime | R |
| Ceftibuten | R | |
| Cefpodox/Cefdinir/Cefditoren | R | |
| Aminoglycosides | Gentamicin | X1 |
| Tobramycin | X1 | |
| Amikacin | X1 | |
| Chloramphenicol | X1 | |
| Clindamycin | I | |
| Macrolides | Erythromycin | I |
| Azithromycin | I | |
| Clarithromycin | I | |
| Ketolide | Telithromycin | I |
| Tetracyclines | Doxycycline | S |
| Minocycline | S | |
| Glycylcycline | Tigecycline | S |
| Daptomycin | S | |
| Glyco/Lipoclycopeptides | Vancomycin | S |
| Teicoplanin | S | |
| Telavancin | S | |
| Fusidic Acid | S | |
| Trimethoprim | S | |
| TMP-SMX | S | |
| Urinary Agents | Nitrofurantoin | S |
| Fosfomycin | S | |
| Other | Rifampin | S |
| Metronidazole | R | |
| Quinupristin dalfoppristin | S | |
| Linezolid | S | |
| Colistimethate | R |
Key
- S susceptible/sensitive (usually)
- I intermediate (variably susceptible/resistant)
- R resistant (or not effective clinically)
- S+ synergistic with cell wall antibiotics
- U sensitive for UTI only (non systemic infection)
- X1 no data
- X2 active in vitro, but not used clinically
- X3 active in vitro, but not clinically effective for Group A strep pharyngitis or infections due to E. faecalis
- X4 active in vitro, but not clinically effective for strep pneumonia
Table Overview
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See Also
References
- ↑ Sanford Guide to Antimicrobial Therapy 2014
