Infectious Diseases in Critical Care Medicine

becomes surrounded by a wide zone of brawny, erythematous, gelatinous, nonpitting edema.
As the lesion evolves it becomes hemorrhagic, necrotic, and covered by an eschar. Frequently
lymphadenopathy is present, if untreated bacteremic dissemination can occur. Incision and
debridement should be avoided because it increases the likelihood of bacteremia (39). A skin
biopsy after the initiation of antibiotics can be done to confirm the diagnosis by culture,
polymerase chain reaction, or immunohistochemical testing. With the concern that strains may
have been modified to be resistant to penicillin, treatment with ciprofloxacin or doxycycline
has been recommended (40).

BITES
Each year, several million Americans are bitten by animals, resulting in approximately 10,000
hospitalizations. Ninety percent of the bites are from dogs and cats, and 3% to 18% of dog bites
and 28% to 80% of cat bites become infected, with occasional sequelae of meningitis,
endocarditis, septic arthritis, and septic shock. Animal or human bites can cause cellulitis due
to skin flora of the recipient of the bite or the oral flora of the biter. Severe infections develop
after bites as a result of hematogenous spread or undetected penetration of deeper structures.
In a prospective multicenter study of infected dog and cat bites,Pasteurellaspp. was the most
common isolate from both dog bites (50%) and cat bites (75%).Pa. caniswas the most common

Table 2 Antimicrobial Therapy and Pathogens Associated with Specific Risk Factors

Risk factor Pathogen Recommended therapy Optional therapy

Dog and cat bites Pasteurella multocida
and other
Pasteurellaspp.
S. aureus,
Capnocytophaga
canimorsus,

Ampicillin/sulbactam

1.5–3 g IV every 6 hr

Ciprofloxacin 500 mg PO or

400 mg IV every 12 hrþ

clindamycin 600–900 mg IV

every 8 hr

Streptococcus
Neisseria canis,
Haemophilus felis,
Capnocytophaga
canimorsus,
anaerobes
Human bites Ei. corrodens,
anaerobes,
S. aureus,
Streptococcus
viridans

Ampicillin/sulbactam

1.5–3 g IV every 6 hr

Ciprofloxacin 500 mg PO or

400 mg IV every 12 hrþ

clindamycin 600–900 mg IV

every 8 hr

Salt water Vibrio vulnificus Doxycycline 200 mg IV
followed by 100–200 mg
IV every 12 hr

Cefotaxime 1–2 g IV every 6–8 hr
or ciprofloxacin 500 mg PO or
400 mg IV every 12 hr
Freshwater or use
of leeches

Aeromonassp. Ciprofloxacin 400 mg IV

every 12 hr

Imipenem/cilastatin 500 mg–1 g
IV every 6–8 hr
Butcher, fish
handler, or
veterinarian

Erysipelothrix

rhusiopathiae

Penicillin G 2–4 mu IV

every 4–6 hr

Ciprofloxacin or cefotaxime or
imipenem/cilastatin 500 mg–1 g
IV every 6–8 hr
Intravenous drug
users

MRSA,P. aeruginosa Vancomycin 15 mg/kg

every 12 hrþ

ceftazidime 1–2 g IV

every 8 hr or cefepime

1–2 g IV every 8–12 hr

Linezolid 600 mg PO or IV every

12 hr or daptomycin 4–6 mg/kg

IV every 24 hr or trimethoprim/

sulfamethoxazole 320/1600 mg

IV or PO 160/800 mg 1–2 tab

every 12 hr or tigecycline

100 mg IV then 50 mg every

12 hr or telavancin 10 mg/kg/

every 24 hrþtobramycin

5.0/kg/dayaor ciprofloxacin

Dose to be adjusted for azotemia except for ceftriaxone, doxycycline, tigecycline, clindamycin and linezolid.
aBased on once a day dose of 5.0 mg/kg, however can be given as 1.7 mg /kg IV every 8 hours.

Abbreviation: mu, million unit.

Severe Skin and Soft Tissue Infections in Critical Care 301