How is MRSA cellulitis treated?

Updated: Jun 14, 2019
  • Author: Thomas E Herchline, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

In many communities, MRSA is the most common isolate obtained from abscesses. [71] Antibiotics used to treat cellulitis associated with abscess or purulent drainage should target MRSA until proven otherwise with culture data. In contrast, for outpatients with nonpurulent cellulitis, the IDSA recommends empiric therapy for infection due to beta-hemolytic streptococci, as it is believed that MRSA plays an uncommon role in these scenarios. [67]

Mild cases that require only outpatient therapy may be treated with TMP-SMX or a tetracycline agent such as doxycycline or minocycline. Available data suggest that doxycycline and TMP-SMX are equivalent for the treatment of mild skin and soft-tissue infections (SSTIs). [72] It is important to note that TMP-SMX and tetracyclines may not have adequate streptococcal coverage and should not be the first choice unless purulence is present. [73] Clindamycin may also be a reasonable choice, depending on local sensitivities of MRSA, but the IDSA estimates that up to 50% of MRSA isolates have intrinsic or constitutive resistance to clindamycin in some regions. [2]

In more severe cases that require parenteral antibiotics to cover MRSA, vancomycin, daptomycin, tigecycline, ceftaroline, and linezolid are appropriate choices. Data are more limited for the newer agents, but they have been shown to have similar efficacy to vancomycin in some clinical trials. [74] Daptomycin has been associated with more rapid resolution of signs and symptoms of cellulitis in some trials. [75, 76] However, vancomycin continues to be the drug of choice because of its overall excellent tolerability profile, efficacy, and cost. [74]

If tinea pedis is considered a possible cause of recurrent cellulitis episodes, treatment with a topical antifungal is recommended. Oral antifungals, such as itraconazole or terbinafine, may be considered in cases of refractory chronic changes or if onychomycosis is providing a source for repeated infection.

Table 1, below, provides an overview of empiric antibiotic therapy by etiology and anatomic location.

Table 1. Empiric Antibiotic Therapy for Cellulitis by Etiology and Anatomic Location (Open Table in a new window)

Location

Likely Organisms

Other Organisms

Complication/ Discussion

Antibiotic Regimen -- Oral/ Outpatient

Indication for Hospitalization

Antibiotic Regimen -- Parenteral/ Hospitalized

Uncomplicated cellulitis

Group A streptococci much more likely than Staphylococcus aureus

 

 

Cephalexin or dicloxacillin

or clindamycin

 

Cefazolin or oxacillin

or nafcillin

Cellulitis, concern for methicillin-resistant S aureus is a concern

Group A streptococci and S aureus

 

 

[(Cephalexin or dicloxacillin or clindamycin) plus trimethoprim/ sulfamethoxazole]

or

Clindamycin

 

Vancomycin

Daptomycin

Ceftaroline

Dog bite

Pasteurella species (50% of wounds)

S aureus

Streptococcus pyogenes

Staphylococci, streptococci

Aerobes --Moraxella and Neisseria

Anaerobes --Fusobacterium, Bacteroides, Porphyromonas, and Prevotella

Capnocytophaga canimorsus may cause sepsis in patients with asplenia/hepatic disease.

Avoid first-generation cephalosporins/ erythromycin/ dicloxacillin.

High likelihood of infection –

Prophylactic antibiotics indicated for the following wounds: deep puncture, hands, requiring surgical repair, immunocompromised host, venous or lymphatic compromise, crush injury.

Requires close follow-up care within 24-48 h.

Amoxicillin/ clavulanate

Penicillin allergic:

Moxifloxacin

Deep wounds or severe wounds;

infections not responding to oral antibiotics

Third-generation cephalosporin (ceftriaxone [Rocephin]) plus metronidazole

or

beta-lactam/beta-lactamase inhibitor (eg, ampicillin/sulbactam) or

fluoroquinolone plus metronidazole

or

carbapenem (ertapenem)

Human bite

Eikenella corrodens (gram-negative facultative anaerobe, 29% of wounds)

Aerobic gram-positive cocci, anaerobes

 

Clenched fist lacerations over metacarpophalangeal joints should be considered human bites; anesthetize wounds and irrigate; reevaluate within 24-48 h.

Intercanine distance >3 cm is likely bite from adult; if wound to child, consider abuse.

Amoxicillin/ clavulanate

Penicillin allergic:

Moxifloxacin

or

(Clindamycin or metronidazole) plus (doxycycline or cefuroxime or trimethoprim/ sulfamethoxazole)

 

Third-generation cephalosporin (Rocephin) plus metronidazole

or

beta-lactam/beta-lactamase inhibitor (eg, ampicillin/sulbactam)

or

fluoroquinolone plus metronidazole

or

carbapenem (ertapenem)

Cat bite

Pasteurella multocida and P septica (75% of wounds)

Staphylococci, streptococci, Bacteroides, Peptostreptococcus, Actinomyces, Fusobacterium, Porphyromonas, and Veillonella parvula

Avoid first-generation cephalosporins/ erythromycin/ dicloxacillin

High likelihood of infection -- Prophylactic antibiotics indicated for the following wounds: deep puncture, hands, requiring surgical repair, immunocompromised host, venous or lymphatic compromise.

Requires close follow-up care within 24-48 h.

Amoxicillin/ clavulanate

Penicillin allergic --

Moxifloxacin

or

(Clindamycin or metronidazole) plus

(doxycycline or cefuroxime or trimethoprim/ sulfamethoxazole)

Deep wounds or severe wounds; infections not responding to oral antibiotics

Third-generation cephalosporin (Rocephin) plus metronidazole

or

beta-lactam/beta-lactamase inhibitor (eg, ampicillin/sulbactam) or

fluoroquinolone plus metronidazole

or

carbapenem (ertapenem)

Preseptal (periorbital) cellulitis

Haemophilus influenzae type b, Streptococcus pneumoniae, S aureus, other streptococcal species, and anaerobes

Nocardia brasiliensis, Bacillus anthracis, Pseudomonas aeruginosa, Neisseria gonorrhoeae, Proteus species, Pasteurella multocida, Mycobacterium tuberculosis

Largest study indicates that H influenzae type b and S pneumoniae not diminished in facial cellulitis as a result of immunizations [25]

Amoxicillin-clavulanate, cefpodoxime, cefdinir

Age < 1 y/ more severe disease require intravenous antibiotic

Third-generation cephalosporin (Rocephin)

Lower extremity --

Complicating saphenous venectomy site after coronary bypass grafting

No pathogen identifiable in most infections, but it is likely to be streptococcal (> staphylococcal)

Non-group A beta-hemolytic streptococci most likely organism; S aureus less common

 

Recurrent episodes common; may be associated with rigors, extreme fatigue, myalgias, and hypotension; some associated with tinea pedis (toe web cultures may be useful in establishing probable pathogen)

Dicloxacillin or cephalexin.

Add trimethoprim/ sulfamethoxazole or tetracycline or clindamycin if concern for methicillin-resistant S aureus

 

First-generation cephalosporin (cefazolin); clindamycin; vancomycin

Breast/arm - - (not mastitis)

Complicating breast cancer surgery/lymph node dissection

No pathogen identifiable in most infections

Group A or Non-group A beta-hemolytic streptococci most likely organisms

 

 

Dicloxacillin, cephalexin. Add trimethoprim/ sulfamethoxazole or tetracycline or clindamycin if concern for methicillin-resistant S aureus

Fever, recent chemotherapy, neutropenia

Multiple regimens, none clearly superior –Piperacillin/tazobactam or ceftazidime plus aminoglycoside;

or

ciprofloxacin plus beta-lactam

or

monotherapy with piperacillin/tazobactam or cefepime

Aquatic environment --

Fresh water/ salt water/ brackish water/ swimming pools/ aquarium

Puncture/ laceration

Aeromonas hydrophila, Pseudomonas and Plesiomonas species, Vibrio species, Erysipelothrix rhusiopathiae, Mycobacterium marinum, and others

 

A hydrophila and Vibrio vulnificus may produce rapidly progressive soft-tissue infection and sepsis

Fluoroquinolone (eg, ciprofloxacin or levofloxacin)

Note: For M marinum infection, use clarithromycin plus either ethambutol or rifampin

 

Third- or fourth-generation cephalosporin (eg, ceftazidime or cefepime) or fluoroquinolone (eg, ciprofloxacin or levofloxacin)

Clenched-fist injury

E corrodens (gram-negative anaerobe, 29 % of wounds); aerobic gram-positive cocci, anaerobes

 

Lacerations over metacarpophalangeal joints should be considered human bites; anesthetize wounds and irrigate; reevaluate within 24-48 h

Lacerations of extensor tendon

Amoxicillin/ clavulanate; penicillin allergic:

Moxifloxacin

or

(clindamycin or metronidazole) plus (doxycycline or cefuroxime or trimethoprim/ sulfamethoxazole)

Failure to respond to oral therapy marked by increasing pain and swelling or purulent drainage

Beta-lactam/beta-lactamase inhibitor (eg, ampicillin/sulbactam)

Odontogenic facial cellulitis

Aerobic and facultative organisms: group A beta-hemolytic streptococci, Neisseria and Eikenella species

Anaerobes: Prevotella and Peptostreptococcus species

 

Require extraction or root canal

Amoxicillin-clavulanate

or

clindamycin

 

Beta-lactam/beta-lactamase inhibitor (eg, ampicillin/sulbactam) or

clindamycin


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