Pathogen

Relevant exposure

Clinical presentation

Beta-hemolytic streptococci

– Disruption to skin barrier

– Known toe web space abnormalities can result in reservoirs for beta-hemolytic streptococci

– Poorly demarcated erythematous rash ± regional lymphadenopathy

Staphylococcus aureus

– Penetrating trauma

– Nasal, perianal, skin colonization

– Existing dermatologic conditions (eg, atopic dermatitis)

– Poorly demarcated erythematous rash ± regional lymphadenopathy

– May have purulent drainage and/or surrounding furuncle, carbuncle, folliculitis, or abscess

Pseudomonas aeruginosa

– Moist environments, hot tubs, hospitalized patients, puncture/wet wounds, nail trauma, injection drug use

– Burn wound infections

– Patients with diabetes and chronic open ulcers

– Cellulitis post penetrating injury/puncture wound

– Cellulitis in patients with neutropenia

– Ecthyma gangrenosum in immunocompromised host

Clostridium spp

– Soil contact

– GI surgery, GI malignancy

– Cellulitis with evidence of crepitus and dark, thin, foul-smelling drainage (patients are often systemically well)

– Clostridial myonecrosis (rapidly spreading, severe infection with muscle involvement)

Aeromonas hydrophila

– Typically associated with traumatic aquatic injury in warm freshwater lakes, streams, rivers (brackish water)

– Contact with medicinal leeches

Cellulitis is nonspecific in appearance and can vary in severity

Vibrio vulnificus

– Contact with salt water or brackish water

– Contact with drippings from raw seafood

– Hemorrhagic bullae in area of cellulitis, often associated with bacteremia

– More severe disease associated with underlying liver disease, diabetes, or hemochromatosis

Erysipelothrix rhusiopathiae

– Contact with saltwater marine life (also associated with freshwater fish); often acquired occupationally

– Contact with infected animals (eg, swine, poultry)

– Subacute cellulitis typically involving hand or fingers that handled fish/shellfish

– Typically occurs in summer

– Causes erysipeloid disease (clearly defined, advancing bright red to purple lesions with shiny, smooth surfaces and central clearing)

Pasteurella multocida

Cat bites (common), occasionally dog bites

Rapidly developing cellulitis (usually within 24 h) ± purulent drainage

Capnocytophaga canimorsus

Dog bites

Cellulitis with septic shock in patients with functional/anatomic asplenia, cirrhosis, alcohol abuse, immunocompromise

Bacillus anthracis

– Contact with infected animals/animal products

– Target of bioterrorism

– Rare in developed world; sporadically occurs in farmers in Africa, Middle East, Caribbean

– Edematous pruritic lesion with subsequent ulceration and swelling

– Ulcer develops necrotic eschar

Francisella tularensis

Contact with or bite from infected animals (especially cats), arthropod bites (particularly ticks)

– Ulceroglandular syndrome (ulcered lesion with central eschar at site of inoculation and localized, tender lymphadenopathy)

– Associated systemic symptoms

Mycobacterium marinum

– Contact with freshwater or salt water, fish tanks, swimming pools

– Usually acquired via traumatic injury

– Often called “fish tank granuloma”

– Typically involving upper extremity and slow growing

– Papular lesion that becomes ulcerative at site of inoculation; ascending lymphatic spread can be seen

– “Sporotrichoid appearance”

– Systemic toxicity usually absent

Mycobacterium fortuitum

– Exposure to freshwater footbaths/pedicures/nail salons

– Razor shaving strongly associated

– Post augmentation mammoplasty and open-heart surgery

– Usually 3-4 weeks after inoculation; initial papule that becomes a boil, then ulcerates and forms multiple boils rapidly (<7 days)

– Can cause granulomas on skin surface