Skin and Soft Tissue Infections Flashcards
Aeromonas hydrophila
Risk factor and comment
Contact w/ recreational water; Contact with medicinal leeches
minor trauma to skin usually leads to inoculation of organism
Vibrio vulnificus, other Vibrio species
Risk factor and comment
Contact w/ salt water or brackish water or raw seafood
Direct inoculation into skin or may be ingested
Hallmark is hemorrhagic bullae in area of cellulitis
Erysipelothrix rhusiopathiae
Risk factor and comment
Contact w/ saltwater marine life (also associated with freshwater fish); contact w/ infected swine and poultry
Usually involves hand or fingers i
Causes erysipeloid disease
Pasteurella multocida
Risk factor and comment
Small aerobic GnR (resist Keflex)
Contact primarily w/cats
Capnocytophaga canimorsus
Risk factor and comment
Contact w/ dogs
Cellulitis; sepsis particularly w/ functional or anatomic asplenia
Bacillus anthracis
Risk factor and comment
Contact w/ infected animals or animal products
Target of bioterrorism
Edematous pruritic lesion with central eschar; spore-forming organism
Francisella tularensis
Risk factor and comment
Contact w/ or bite from infected animal (rabbits, cats) or ticks
Ulceroglandular syndrome: ulcerative lesion with central eschar, localized tender lymphadenopathy;
Constitutional symptoms are often present
Mycobacterium marinum
Risk factor and comment
Contact with water (including fish tanks and swimming pools)
papular become ulcerative; ascending lymphatic spread can be seen (“sporotrichoid” appearance);
systemic toxicity usually absent
Mycobacterium fortuitum
Risk factor and comment
Exposure to freshwater footbaths/pedicures at nail salons;
augmentation mammoplasty and open heart surgery
Multiple boils; razor shaving strongly associated
Types of Nec Fasc and etiology
NF type I - polymycrobial
NF type II - monomycrobial: strep pyogenes, staph, Vibrio vulnificus, strep aggalactiae
NF type III - Clost perfringens
Risk factors for Vibrio Vulnificus
Liver disease
Hemochromatosis
Exposure to estuaries
_____ is a fifth-generation cephalosporin approved for treatment of SSTIs
Ceftaroline
Primary treatment of a cutaneous abscess is
Incision and drainage.
Antibiotics if: I & D is inadequate; in extensive disease; immunodeficiency/comorbidities; for very young or very old patients; areas are challenging to drain.
6 independent lab indicators that are associated with an increased likelihood of necrotizing fasciitis:
C-reactive protein (≥15.0 mg/dL, total leukocyte count (>15,000-25,000/μL, hemoglobin (<11-13.5 g/dL sodium (<135 mEq/L creatinine (>1.6 mg/dL glucose (>180 mg/dL.
Recommended abx for animal bite infections (in gral): nfected wounds require antibiotics.
β-lactam/β-lactamase inhibitor combinations,
carbapenems,
clindamycin or metronidazole and a fluoroquinolone (for allergic to β-lactam)
Diabetic Foot Infections classification
Mild
Moderate infections, the erythema expands more than 2 cm around the ulcer or extends deeper than the skin and subcutaneous tissues. The patient must not meet SIRS criteria.
Severe
Pathogen-directed Tx for TSS
For S. pyogenes: penicillin plus clindamycin.
Methicillin-sensitive S. aureus: nafcillin or oxacillin plus clindamycin;
MRSA: vancomycin plus clindamycin
Adjunctive IVIG ?? Neutralizing antibodies to streptococcal toxins
Management of Animal Bites
Wound care: Image if needed Wound closure: NO Prophylactic antibiotics Vaccines (tetanus and rabies)
6 pathogens that can cause infection
after cat bites?
Pasteurella species
Anaerobic bacteria: e.g., Fusobacteria
Bartonella henselae ( Cat Scratch dis.)
Rabies virus
S.aureus *
Streptococcal species *
Rat bite fever in USA and Tx
Streptobacillus moniliformis (pleomorphic GnR)
Tx: Penicillin or doxycycline
Rat bite fever in Asia
Spirillium minus
Common findings in Streptobacillus moniliformis, rat bite fever
Fever,
extremity rash (Mac./Pap, pustular, petechial, purpuric
Symmetrical polyarthralgia
Eikenella corrodens, associated with:
Susceptibility -
Resistance -
Clenched fist injury
Anaerobic small GnR
Susceptible to: penicillins, FQs, TMP/SMX, Doxy, and ESCs.
Resistant to: Cephalexin, clinda, erythro, and metronidazole
Possible etiology of Folliculitis?
- S. aureus
- P. aeruginosa ( from hot tub; under swimming trunks)
- C. albicans (esp. In obese patient)
- Malassezia furfur lipophilic yeast (formerly Pityrosporum species)
- Idiopathic Eosinophilic pustular folliculitis in AIDS patients
Microbial etiology of Impetigo ?
Bullous impetigo: S.aureus
Non-bullous impetigo: Streptococcus pyogenes, group A
Complications of S.pyogenes, S.
dysgalactiae (Gps C&G) impetigo
- Post-streptococcal glomerulonephritis due to nephritogenic strains
- Rheumatic fever hs “never” occurrs after streptococcal impetigo
With Erysipelas on the face, could be . . .
S. aureus
Erysipelothrix (Gram + rod) treatment?
Treatment: Penicillin, cephalosporins, clindamycin, fluoroquinolone
Erysipelothrix (Gram + rod) Diagnosis?
Culture of deep dermis (aspirate or biopsy)
Diference between S. pyogenes and S. aureus TSS
S. aureus most commonly is NOT invasive in TSS
S.aureus and S.pyogenes toxins:
S.aureus - TSST and exfolliative toxin
S.pyogenes toxins: TSST and pyrogenic exotoxin
Organisms Whose Growth is
Stimulated by Excess Iron
V E L A R Y
Vibrio vulnificus
Escherichia coli
Listeria monocytogenes
Aeromonas hydrophilia
Rhizopus species (Mucor)
Yersinia enterocolitica
Organisms to consider w/water exposure . . .
Aeromonas species
Edwardsiella tarda
Erysipelothrx rhyusiopathiae
Vibrio vulnificus
M. marinum
Parinaud Syndrome
oculoglandular fever
> follicular conjunctivitis,
localized adenopathy (cervical, submandibular, pre auricular) and
fever.
Some bugs:
< Bartonella henselae (Cat Scratch Disease),
< adenovirus and
< tularemia.
