Module 8: SSTI / UTI Flashcards
- Involves any layer (epidermis, dermis), subcutaneous fat, fascia, or muscle
- Can be mild and self-limiting to severe-progressing to complicated infections (septic arthritis, osteomyelitis, bacteremia, endocarditis, etc.)
- Empiric treatment based on severity and site of infection, patient underlying disease, and probable etiology
SSTI (Skin and Soft Tissue Infections)
Factors that predispose to skin and soft tissue infection:
- High concentrations of bacteria (>105)
- Excessive moisture (eg obesity)
- Inadequate blood supply
- Availability of bacterial nutrients
- Damage to corneal layer allowing bacterial penetration
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Cell______
Definition: Acute inflammation and infection of skin and subcutaneous fat. This (which includes erysipelas) manifests as an area of skin erythema, edema, and warmth; it develops as a result of bacterial entry via breaches in the skin barrier.
Cellulitis
Predisposing factors of cell______:
Venous or lymphatic insufficiency, DM (or other immunosupressive states), alcoholism, obesity, breaks in the skin / skin trauma, pre-existing skin infections.
Cellulitis
Examples of presdisposing factors of cell______:
- Skin barrier disruption due to trauma (such as abrasion, penetrating wound, pressure ulcer, venous leg ulcer, insect bite, injection drug use)
- Skin inflammation (such as eczema, radiation therapy)
- Edema due to impaired lymphatic drainage
- Edema due to venous insufficiency
- Obesity
- Immunosuppression (such as diabetes or HIV infection)
- Breaks in the skin between the toes (“toe web intertrigo”); these may be clinically inapparent
- Preexisting skin infection (such as tinea pedis, impetigo, varicella)
Cellulitis
Signs and symptoms of c_________:
- erythema
- edema
- warm to touch
- diffuse tenderness
- indistinct border
- lymphadenopathy
Cellulitis
Common bacterial causes of cellu_____ (otherwise healthy):
Think skin flora (penetrating compromised skin), unless otherwise infectious source:
- Group A Streptococcus (GAS)(β hemolytic strep) - primarily S. Pyogenes
- S aureus (MSSA)
- S aureus (MRSA)
- Haemophilus influenzae (children)
Cellulitis
C_-M___: Causes serious infections in otherwise healthy persons who have not been recently hospitalized.
- Transmission of MRSA (complicated or uncomplicated disease) associated with minor skin trauma, sharing of sports or personal care equipment, sharing of close quarters, recent hospitalization or surgery, + others.
- No obvious risk factors, but associated with dermatological conditions, diabetes and smoking. NOTE treatment variation where CA-MRSA is suspect!
CA-MRSA
Complicated Cellulitis: Involves the immunocompromised, DM, vascular insufficient, use of injectable drugs, etc.
Complicated Cellulitis
Pathogens of complicated cellulitis:
Pathogens:
MSSA, HA-MRSA, CA-MRSA, Enterobacteriaceae, P aeruginosa, anaerobes
Predisposing factors increase risk of poly-microbial disease
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Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Mild cellulitis:
dicloxacillin, cephalexin, clindamycin
CA-MRSA suspected or allergy to PCN clindamycin, smz/tmp, doxycycline
-
Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Mild cellulitis:
dicloxacillin, cephalexin, clindamycin
-
Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Mild cellulitis:
CA-MRSA suspected or allergy to PCN clindamycin, smz/tmp, doxycycline
-
Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Moderate-to-severe cellulitis:
nafcillin, cefazolin, clindamycin
CA-MRSA suspect or allergy to PCN: vanco, linezolid, daptomycin, ceftaroline, televancin
-
Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Moderate-to-severe cellulitis:
nafcillin, cefazolin, clindamycin
-
Treatment of cellulitis in otherwise healthy people: 10 days or 4 to 5 days after clinical improvement.
Moderate-to-severe cellulitis:
CA-MRSA suspect or allergy to PCN: vanco, linezolid, daptomycin, ceftaroline, televancin
-
Oral ABT agents for treatment of MRSA infection in adults:
- clindamycin
- trimethoprim-sulfamethoxazole
- doxycycline
- minocycline
- linezolid
- tedizolid
- delafloxacin
-
Regarding cell______:
Patient specific factors? Allergies, drug-drug/drug-disease interactions, pregnancy, children, etc…
Recall Examples:
- Avoid penicillins or cephalosporins in patients with history of hypersensitivity (type I) to these classes of medication
- DI with quinolones and mono- and di- valent cations (Ca, Mg, etc), iron
- Avoid “cyclines” (doxycycline, tetracycline) and quinolones in children
- Altered renal, hepatic, biliary functions
Cellulitis
If CA-MRSA is suspected (in cellulitis), clindamycin, SMZ-TMP, or doxycycline must be added to the treatment regimen.
-
Hypersensitivity reactions occur when penicillin is degraded to penicilloic acid and other compounds that combine with proteins in the body to form antigens, which cause antibody formation.
-
If hypersensitive to ABTs like penicillin:
- Use alternative antibiotic
- Skin testing can be done
-
Cross-reactivity between Penicillins and cephalosporins or carbapenems ~ 3-7%
- Use alternative antibiotic in the case of prior anaphylaxsis
-
Er_______s:
More superficial infection w/ very sharp, raised border, systemic sxs
Erysipelas
Necrotizing fasciitis:
- deep subcutaneous infection that causes necrosis of the fascia and subcutaneous fat with rapidly progressive inflammation.
-
Necrotizing fasciitis:
Treatment of necrotizing infection consists of early and aggressive surgical exploration and debridement of necrotic tissue, together with broad spectrum empiric antibiotic therapy and hemodynamic support.
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Animal bites:
Most animal bites are caused by dogs, cats, and humans. The predominant organisms in animal bite wounds are the oral flora of the biting animal as well as human skin flora (such as Staphylococci and Streptococci).
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Animal bites:
Most animal bites are caused by dogs, cats, and humans. The predominant organisms in animal bite wounds are the oral flora of the biting animal as well as human skin flora (such as Staphylococci and Streptococci).
- Pasteurella multocida
- Prophylaxis - Prophylactic antibiotics reduce the rate of infection due to some animal bites, especially cat bites.
-
Primary agent of choice for animal bites:
Amoxicillin-
clavulanate (Augmentin)
- 875/125 mg twice daily
- 20 mg/kg per dose (amoxicillin component) two times daily (maximum 875 mg amoxicillin and 125 mg clavulinic acid per dose)*
-
Alternate empiric regimens include:
One of the following agents with activity against P. multocida:
- Doxycycline (Not recommended in children <8 years of age)
- TMP-SMX
- Penicillin VK
- Cefuroxime
- Moxifloxacin (Use with caution in children <18 years of age)
PLUS
One of the following agents with anaerobic activity:
- Metronidazole
- Clindamycin
Duration is 7 days.
-
Imp_____:
Seen mostly in children, highly communicable, esp. in hot humid weather.
S. Pyogenes (β hemolytic strep), S. aureus
Treatment:
- May resolve on its own with non-pharmacological interventions
- Antistaphylococcal penicillins (eg dicloxacillin)
- 1st gen cephalosporin (eg cephalexin)
If MRSA is suspected or PCN allergy:
- Clindamycin, SMZ/TMP, Doxycycline
NOTE: tetracyclines (including doxycycline) should be avoided in children
Topical: Mupirocin or Bacitracin for nonbullous impetigo.
Impetigo
U__: Presence of microorganisms in the urinary tract that cannot be accounted for by contamination.
UTI
U__s and the Elderly:
- In older adults who are cognitively intact, the diagnosis of symptomatic UTI is relatively straightforward.
UTI
