Welcome, PharmD students, to this MCQ quiz on Acute Bacterial Skin and Skin Structure Infections (ABSSSIs)! These common infections, including cellulitis, erysipelas, and abscesses, frequently require pharmacist intervention for appropriate management and antimicrobial selection. Understanding the common pathogens, clinical presentations, differentiation between purulent and non-purulent infections, the crucial role of incision and drainage for abscesses, and evidence-based antimicrobial choices (especially considering MRSA) is vital. This quiz will test your knowledge on these key principles to help you confidently manage patients with ABSSSIs. Let’s begin!
1. Acute Bacterial Skin and Skin Structure Infections (ABSSSIs) encompass which of the following conditions?
- a) Only minor fungal rashes.
- b) Cellulitis/erysipelas, wound infections, and major cutaneous abscesses.
- c) Viral warts and cold sores.
- d) Only infections requiring surgical intervention.
Answer: b) Cellulitis/erysipelas, wound infections, and major cutaneous abscesses.
2. The most common bacterial pathogens responsible for community-acquired ABSSSIs are:
- a) Pseudomonas aeruginosa and Candida albicans.
- b) Staphylococcus aureus (both MSSA and MRSA) and Streptococcus pyogenes (Group A Streptococcus).
- c) Clostridium difficile and Escherichia coli.
- d) Haemophilus influenzae and Moraxella catarrhalis.
Answer: b) Staphylococcus aureus (both MSSA and MRSA) and Streptococcus pyogenes (Group A Streptococcus).
3. Cellulitis is an infection of the dermis and subcutaneous tissue characterized by:
- a) Sharply demarcated, raised borders and intense itching.
- b) A localized collection of pus within a fluctuant nodule.
- c) Spreading erythema, warmth, swelling, and tenderness with poorly defined borders.
- d) Superficial vesicles that rupture and form honey-colored crusts.
Answer: c) Spreading erythema, warmth, swelling, and tenderness with poorly defined borders.
4. Erysipelas is a superficial form of cellulitis that typically presents with:
- a) Deep-seated nodules and sinus tracts.
- b) A fiery red, indurated plaque with sharply demarcated, raised borders, often involving lymphatic streaking.
- c) Painless, non-erythematous swelling.
- d) Necrotic tissue and gas production.
Answer: b) A fiery red, indurated plaque with sharply demarcated, raised borders, often involving lymphatic streaking.
5. A major cutaneous abscess is best described as:
- a) A diffuse, non-fluctuant area of skin redness.
- b) A collection of pus within the dermis or subcutaneous tissue, often presenting as a painful, tender, fluctuant, and erythematous nodule or pustule.
- c) A superficial fungal infection.
- d) A viral exanthem.
Answer: b) A collection of pus within the dermis or subcutaneous tissue, often presenting as a painful, tender, fluctuant, and erythematous nodule or pustule.
6. The cornerstone of treatment for a sizable, fluctuant cutaneous abscess is:
- a) Oral antibiotic therapy alone.
- b) Topical antibiotic therapy alone.
- c) Incision and drainage (I&D).
- d) Warm compresses only, without drainage.
Answer: c) Incision and drainage (I&D).
7. When deciding on empiric antibiotic therapy for an ABSSSI, a key consideration is whether the infection is purulent or non-purulent because:
- a) Non-purulent infections are always viral.
- b) Purulent infections (like abscesses, furuncles, carbuncles) have a higher likelihood of being caused by Staphylococcus aureus (including MRSA), while non-purulent cellulitis is more often caused by Streptococci.
- c) Only purulent infections require antibiotics.
- d) Antibiotic duration is always shorter for purulent infections.
Answer: b) Purulent infections (like abscesses, furuncles, carbuncles) have a higher likelihood of being caused by Staphylococcus aureus (including MRSA), while non-purulent cellulitis is more often caused by Streptococci.
8. For a patient with non-purulent cellulitis and no risk factors for MRSA, a common empiric oral antibiotic choice would target primarily Streptococci and MSSA. Which of the following is appropriate?
- a) Vancomycin
- b) Dicloxacillin, cephalexin, or clindamycin
- c) Doxycycline
- d) Linezolid
Answer: b) Dicloxacillin, cephalexin, or clindamycin
9. Which of the following oral antibiotics provides reliable coverage against community-associated MRSA (CA-MRSA) and is often used for purulent ABSSSIs?
- a) Amoxicillin
- b) Cephalexin
- c) Trimethoprim/sulfamethoxazole or Doxycycline/Minocycline
- d) Penicillin VK
Answer: c) Trimethoprim/sulfamethoxazole or Doxycycline/Minocycline
10. Clindamycin is an option for ABSSSIs with suspected MRSA. However, an important consideration before using clindamycin is:
- a) It has no activity against Streptococci.
- b) The potential for inducible clindamycin resistance in erythromycin-resistant, clindamycin-susceptible S. aureus isolates (D-test).
- c) It only comes in an IV formulation.
- d) It causes severe nephrotoxicity.
Answer: b) The potential for inducible clindamycin resistance in erythromycin-resistant, clindamycin-susceptible S. aureus isolates (D-test).
11. Risk factors for acquiring community-associated MRSA (CA-MRSA) include:
- a) Living in a rural area.
- b) Recent hospitalization or surgery.
- c) History of IV drug use, incarceration, or participation in contact sports.
- d) Being over 65 years of age primarily.
Answer: c) History of IV drug use, incarceration, or participation in contact sports.
12. Which of the following signs and symptoms would suggest a more severe ABSSSI requiring hospitalization or parenteral antibiotics?
- a) Mild localized redness around a small cut.
- b) Systemic signs of infection (e.g., fever >100.4°F/38°C, tachycardia, hypotension), rapid progression of cellulitis, or extensive disease.
- c) A minor abscess that is draining spontaneously.
- d) Itching without significant pain.
Answer: b) Systemic signs of infection (e.g., fever >100.4°F/38°C, tachycardia, hypotension), rapid progression of cellulitis, or extensive disease.
13. For hospitalized patients with severe non-purulent cellulitis, a common empiric IV antibiotic regimen targeting Streptococci and MSSA might include:
- a) Oral doxycycline
- b) IV cefazolin or nafcillin/oxacillin
- c) Oral trimethoprim/sulfamethoxazole
- d) IV metronidazole
Answer: b) IV cefazolin or nafcillin/oxacillin
14. Vancomycin is often a first-line IV agent for ABSSSIs when MRSA is suspected or confirmed, particularly in hospitalized patients. Its mechanism of action is:
- a) Inhibition of bacterial protein synthesis.
- b) Inhibition of bacterial cell wall synthesis by binding to D-Ala-D-Ala precursors.
- c) Disruption of DNA gyrase.
- d) Damage to the bacterial cell membrane.
Answer: b) Inhibition of bacterial cell wall synthesis by binding to D-Ala-D-Ala precursors.
15. Linezolid and tedizolid are oxazolidinone antibiotics with excellent activity against MRSA and other Gram-positive pathogens. They are advantageous because:
- a) They are only available in IV formulation.
- b) They have excellent oral bioavailability, allowing for an IV-to-oral switch.
- c) They have no significant drug interactions.
- d) They primarily target Gram-negative bacteria.
Answer: b) They have excellent oral bioavailability, allowing for an IV-to-oral switch.
16. What is a common duration of antibiotic therapy for uncomplicated cellulitis that is responding well to treatment?
- a) 1-2 days
- b) 3 days
- c) 5-10 days, depending on clinical response.
- d) At least 21 days.
Answer: c) 5-10 days, depending on clinical response.
17. Which non-pharmacological measure is often recommended for patients with cellulitis of an extremity?
- a) Vigorous exercise of the affected limb.
- b) Applying tight compression bandages.
- c) Elevation of the affected limb to reduce swelling and pain.
- d) Keeping the limb dependent (hanging down).
Answer: c) Elevation of the affected limb to reduce swelling and pain.
18. A diabetic foot infection is generally considered a complicated skin and soft tissue infection, often requiring:
- a) No antibiotic therapy.
- b) Broader spectrum antimicrobial coverage (including Gram-negatives and anaerobes depending on severity/chronicity) and meticulous wound care.
- c) Only topical antibiotics.
- d) A short 3-day course of oral antibiotics.
Answer: b) Broader spectrum antimicrobial coverage (including Gram-negatives and anaerobes depending on severity/chronicity) and meticulous wound care.
19. Animal bites (e.g., dog or cat bites) often require empiric antibiotic coverage for:
- a) Only Staphylococcus aureus.
- b) A broad range of organisms including aerobes and anaerobes (e.g., Pasteurella multocida, Staphylococci, Streptococci, anaerobes).
- c) Only viral pathogens.
- d) Fungal pathogens.
Answer: b) A broad range of organisms including aerobes and anaerobes (e.g., Pasteurella multocida, Staphylococci, Streptococci, anaerobes). (Amoxicillin/clavulanate is a common choice).
20. Impetigo, a superficial skin infection common in children, is typically caused by Staphylococcus aureus or Streptococcus pyogenes and presents as:
- a) Deep, painful nodules.
- b) Vesicles or pustules that rupture and form characteristic honey-colored crusts.
- c) Sharply demarcated, raised erythematous plaques.
- d) Diffuse, non-blistering redness.
Answer: b) Vesicles or pustules that rupture and form characteristic honey-colored crusts.
21. The decision to obtain wound cultures for an ABSSSI is often based on:
- a) The patient’s preference for the swab type.
- b) Severity of infection, presence of purulence, history of recurrent infections, immunocompromised status, or failure of empiric therapy.
- c) The color of the skin infection.
- d) The time of day.
Answer: b) Severity of infection, presence of purulence, history of recurrent infections, immunocompromised status, or failure of empiric therapy.
22. The “S” in the SBAR communication tool, when reporting an ABSSSI to a physician, would concisely state:
- a) The patient’s entire medical history.
- b) “I am calling about [Patient Name] in [Location], who presents with [chief complaint, e.g., a swollen, red leg].”
- c) Your complete assessment of all body systems.
- d) A detailed list of all recommended treatments.
Answer: b) “I am calling about [Patient Name] in [Location], who presents with [chief complaint, e.g., a swollen, red leg].”
23. Which of the following is NOT a typical sign of systemic infection that might accompany a severe ABSSSI?
- a) Fever or hypothermia
- b) Tachycardia
- c) Leukocytosis or leukopenia
- d) Localized itching without redness or warmth
Answer: d) Localized itching without redness or warmth
24. For mild cutaneous abscesses where I&D is performed, are systemic antibiotics always necessary?
- a) Yes, all abscesses require at least 10 days of antibiotics.
- b) No, for small, simple abscesses in healthy individuals, I&D alone may be sufficient. Antibiotics are considered if there’s significant surrounding cellulitis, systemic signs, or specific patient factors.
- c) Only topical antibiotics are ever needed.
- d) Antibiotics are only needed if the pus is green.
Answer: b) No, for small, simple abscesses in healthy individuals, I&D alone may be sufficient. Antibiotics are considered if there’s significant surrounding cellulitis, systemic signs, or specific patient factors.
25. Recurrent skin abscesses or furunculosis might prompt consideration for:
- a) Lifelong antibiotic therapy.
- b) Screening for S. aureus (including MRSA) nasal colonization and potential decolonization strategies.
- c) Avoiding all skin cleansing.
- d) Daily high-dose vitamin C.
Answer: b) Screening for S. aureus (including MRSA) nasal colonization and potential decolonization strategies.
26. When treating an ABSSSI, it is important to counsel the patient to monitor for:
- a) Improvement in taste sensation.
- b) Signs of worsening infection (e.g., expanding redness, increased pain, fever) or adverse drug effects, and when to seek follow-up.
- c) Changes in hair color.
- d) Their favorite TV shows.
Answer: b) Signs of worsening infection (e.g., expanding redness, increased pain, fever) or adverse drug effects, and when to seek follow-up.
27. The term “folliculitis” refers to inflammation of:
- a) Sweat glands
- b) Hair follicles
- c) Sebaceous glands
- d) Nails
Answer: b) Hair follicles
28. A “carbuncle” is a more extensive and deeper infection than a furuncle, consisting of:
- a) A single inflamed hair follicle.
- b) A cluster of interconnected furuncles (boils) with multiple draining points.
- c) A superficial skin rash.
- d) A fungal infection of the nail.
Answer: b) A cluster of interconnected furuncles (boils) with multiple draining points.
29. Prevention strategies for ABSSSIs include:
- a) Avoiding all handwashing.
- b) Good personal hygiene, proper wound care for minor injuries, and avoiding sharing personal items like towels or razors.
- c) Frequent use of systemic antibiotics for prophylaxis in healthy individuals.
- d) Never exercising.
Answer: b) Good personal hygiene, proper wound care for minor injuries, and avoiding sharing personal items like towels or razors.
30. In the FDA’s definition of ABSSSI for clinical trial purposes, the minimum lesion size for cellulitis/erysipelas is typically:
- a) At least 1 cm²
- b) At least 10 cm²
- c) At least 75 cm² of erythema
- d) Any visible redness
Answer: c) At least 75 cm² of erythema
31. Doxycycline, a tetracycline antibiotic, is an oral option for MRSA ABSSSIs. Its mechanism of action is:
- a) Inhibition of cell wall synthesis.
- b) Inhibition of bacterial protein synthesis by binding to the 30S ribosomal subunit.
- c) Inhibition of DNA gyrase.
- d) Disruption of the cell membrane.
Answer: b) Inhibition of bacterial protein synthesis by binding to the 30S ribosomal subunit.
32. Which statement is TRUE regarding the treatment of ABSSSIs caused by MSSA (Methicillin-Susceptible Staphylococcus aureus)?
- a) Vancomycin is always the preferred agent.
- b) Anti-staphylococcal penicillins (e.g., dicloxacillin, nafcillin) or first-generation cephalosporins (e.g., cephalexin, cefazolin) are generally effective.
- c) These infections do not require antibiotics.
- d) Only topical therapy is effective.
Answer: b) Anti-staphylococcal penicillins (e.g., dicloxacillin, nafcillin) or first-generation cephalosporins (e.g., cephalexin, cefazolin) are generally effective.
33. A patient presents with a rapidly spreading cellulitis on their leg, with bullae formation and systemic toxicity (high fever, hypotension). This presentation is concerning for:
- a) A mild fungal infection.
- b) A more severe or necrotizing infection that requires urgent medical/surgical evaluation.
- c) Simple erysipelas.
- d) Contact dermatitis.
Answer: b) A more severe or necrotizing infection that requires urgent medical/surgical evaluation.
34. When is empiric coverage for anaerobic bacteria typically considered in an ABSSSI?
- a) For all cases of simple cellulitis.
- b) In infections related to bites (human or animal), diabetic foot ulcers, or infections near mucous membranes (e.g., perirectal abscess).
- c) Only if the patient has a history of penicillin allergy.
- d) Never, as anaerobes do not cause skin infections.
Answer: b) In infections related to bites (human or animal), diabetic foot ulcers, or infections near mucous membranes (e.g., perirectal abscess).
35. For an outpatient with a drained cutaneous abscess and minimal surrounding cellulitis, who is otherwise healthy, current guidelines often suggest:
- a) Always prescribing a 10-day course of vancomycin.
- b) Incision and drainage alone may be sufficient, with antibiotics reserved for specific indications (e.g., extensive cellulitis, systemic signs, comorbidities).
- c) A mandatory 3-week course of IV antibiotics.
- d) Topical steroids only.
Answer: b) Incision and drainage alone may be sufficient, with antibiotics reserved for specific indications (e.g., extensive cellulitis, systemic signs, comorbidities).
36. The “Panton-Valentine Leukocidin (PVL)” is a cytotoxin produced by some strains of Staphylococcus aureus, particularly CA-MRSA, and is associated with:
- a) Decreased virulence.
- b) More severe skin infections, including recurrent abscesses and necrotizing pneumonia.
- c) Enhanced susceptibility to beta-lactam antibiotics.
- d) Protection against streptococcal infections.
Answer: b) More severe skin infections, including recurrent abscesses and necrotizing pneumonia.
37. Marking the borders of cellulitis with a pen can be helpful to:
- a) Ensure the antibiotic is applied correctly.
- b) Monitor the progression (spreading or receding) of the erythema.
- c) Determine the patient’s skin type.
- d) Identify the causative pathogen.
Answer: b) Monitor the progression (spreading or receding) of the erythema.
38. Which of the following is an important counseling point for patients taking trimethoprim/sulfamethoxazole for an ABSSSI?
- a) Take with plenty of water to prevent crystalluria, and be aware of potential sulfa allergy.
- b) Avoid all sun exposure due to guaranteed severe photosensitivity.
- c) This medication only works against viruses.
- d) Expect your urine to turn orange.
Answer: a) Take with plenty of water to prevent crystalluria, and be aware of potential sulfa allergy.
39. The choice between oral and intravenous antibiotics for ABSSSI primarily depends on:
- a) The cost of the medication only.
- b) The severity of the infection, presence of systemic signs, patient comorbidities, and ability to tolerate oral medications.
- c) The pharmacist’s preference.
- d) The time of day the patient presents.
Answer: b) The severity of the infection, presence of systemic signs, patient comorbidities, and ability to tolerate oral medications.
40. Delafloxacin is a newer fluoroquinolone with activity against MRSA. Its use is generally reserved for:
- a) All uncomplicated skin infections as a first-line agent.
- b) Specific situations where its spectrum (including MRSA and Pseudomonas for some) is beneficial, often for more complicated infections, balancing its risks and benefits.
- c) Only viral skin infections.
- d) Only when combined with vancomycin.
Answer: b) Specific situations where its spectrum (including MRSA and Pseudomonas for some) is beneficial, often for more complicated infections, balancing its risks and benefits.
41. If a patient with cellulitis is not improving after 48-72 hours of appropriate oral antibiotic therapy, what is the next step?
- a) Continue the same antibiotic for another week.
- b) Double the dose of the current antibiotic.
- c) Re-evaluate the patient, consider alternative diagnoses, assess for resistance, and consider a change in therapy or referral/hospitalization.
- d) Discontinue all antibiotics.
Answer: c) Re-evaluate the patient, consider alternative diagnoses, assess for resistance, and consider a change in therapy or referral/hospitalization.
42. Which skin layer is primarily affected in erysipelas, leading to its characteristically sharp demarcation?
- a) Epidermis only
- b) Dermis (more superficially than typical cellulitis) and superficial lymphatics
- c) Subcutaneous tissue
- d) Muscle fascia
Answer: b) Dermis (more superficially than typical cellulitis) and superficial lymphatics
43. Factors that might predispose a patient to developing ABSSSIs include:
- a) Excellent skin hygiene.
- b) Breaks in the skin (cuts, abrasions, insect bites), lymphedema, peripheral vascular disease, and immunosuppression.
- c) Regular use of moisturizers.
- d) A diet high in vitamin C.
Answer: b) Breaks in the skin (cuts, abrasions, insect bites), lymphedema, peripheral vascular disease, and immunosuppression.
44. A patient presents with a localized, painful, red, and swollen area on their arm after an insect bite a few days ago. There is no fluctuance or drainage. This is most likely:
- a) A simple insect bite reaction.
- b) Cellulitis secondary to the insect bite.
- c) A fully formed abscess requiring immediate I&D.
- d) Erysipelas.
Answer: b) Cellulitis secondary to the insect bite.
45. The primary goal of surgical prophylaxis, as discussed in the context of preventing wound infections (a type of ABSSSI), is to:
- a) Treat an established infection.
- b) Reduce the burden of microorganisms at the surgical site at the time of incision to prevent postoperative infection.
- c) Sterilize the patient’s entire body.
- d) Eliminate the need for sterile surgical technique.
Answer: b) Reduce the burden of microorganisms at the surgical site at the time of incision to prevent postoperative infection.
46. For most ABSSSIs, obtaining a Gram stain and culture from needle aspiration of intact cellulitis (without abscess or open wound) is:
- a) Always mandatory and highly sensitive.
- b) Generally low yield and not routinely recommended unless specific circumstances warrant it.
- c) The primary method for diagnosis.
- d) Used to determine the patient’s blood type.
Answer: b) Generally low yield and not routinely recommended unless specific circumstances warrant it.
47. Which of the following newer lipoglycopeptides offers the advantage of single-dose or once-weekly dosing for ABSSSIs due to its very long half-life?
- a) Vancomycin
- b) Linezolid
- c) Dalbavancin or Oritavancin
- d) Daptomycin
Answer: c) Dalbavancin or Oritavancin
48. Patients with recurrent ABSSSIs, especially those caused by MRSA, might benefit from counseling on:
- a) Avoiding all future contact with other people.
- b) Decolonization measures (e.g., mupirocin nasal ointment, chlorhexidine washes) if recommended by a physician, and environmental hygiene.
- c) Taking prophylactic antibiotics indefinitely without medical supervision.
- d) Applying potent topical steroids to all skin lesions.
Answer: b) Decolonization measures (e.g., mupirocin nasal ointment, chlorhexidine washes) if recommended by a physician, and environmental hygiene.
49. The “A” component of an SBAR communication when a pharmacist is concerned about an antibiotic choice for an ABSSSI might be:
- a) “The patient is Mrs. Smith in room 101.”
- b) “Mrs. Smith has a history of penicillin allergy and renal insufficiency.”
- c) “Based on her allergy and renal function, I believe the current antibiotic order for [Drug X] is inappropriate and may pose a risk.”
- d) “I recommend changing to [Drug Y] at an adjusted dose.”
Answer: c) “Based on her allergy and renal function, I believe the current antibiotic order for [Drug X] is inappropriate and may pose a risk.”
50. The pharmacist’s role in managing ABSSSIs includes all of the following EXCEPT:
- a) Counseling on appropriate antibiotic use, adherence, and potential side effects.
- b) Identifying patients who are candidates for self-care versus those needing referral.
- c) Performing surgical incision and drainage of large abscesses in the community pharmacy.
- d) Recommending appropriate non-pharmacological measures like wound care and elevation.
Answer: c) Performing surgical incision and drainage of large abscesses in the community pharmacy.