CBIC Multidrug-Resistant Organisms 1 — Questions and Answers
Question 1: Which of the following is the primary route of transmission for Methicillin-resistant Staphylococcus aureus (MRSA) in healthcare settings?
- Airborne droplet nuclei
- Direct and indirect contact (Correct answer)
- Common vehicle (contaminated food/water)
- Vector-borne transmission
Correct answer: Direct and indirect contact
MRSA is primarily transmitted via direct contact with colonized or infected individuals and indirect contact through contaminated surfaces or equipment.
Question 2: Vancomycin-resistant Enterococcus (VRE) can survive on dry environmental surfaces for up to:
- 24 hours
- 1 week
- Several weeks to months (Correct answer)
- Only a few hours
Correct answer: Several weeks to months
VRE is notably hardy and can persist on dry inanimate surfaces for several weeks to months, making environmental cleaning critical for control.
Question 3: Extended-spectrum beta-lactamase (ESBL)-producing organisms are MOST resistant to which class of antibiotics?
- Aminoglycosides
- Fluoroquinolones
- Penicillins and cephalosporins (Correct answer)
- Macrolides
Correct answer: Penicillins and cephalosporins
ESBLs are enzymes that hydrolyze and inactivate most penicillins and cephalosporins, making ESBL-producing organisms resistant to these antibiotic classes.
Question 4: According to CDC/HICPAC guidelines, patients colonized or infected with an MDRO should be placed on which type of precautions?
- Airborne precautions
- Droplet precautions
- Contact precautions (Correct answer)
- Protective environment
Correct answer: Contact precautions
Contact precautions are the standard recommendation for MDROs to prevent transmission via direct or indirect contact with the patient or their environment.
Question 5: Active surveillance cultures (ASC) for MDROs are BEST described as cultures obtained from:
- Patients showing signs of clinical infection only
- All staff members upon hire
- Asymptomatic patients to detect colonization (Correct answer)
- Patients with positive blood cultures
Correct answer: Asymptomatic patients to detect colonization
Active surveillance cultures are obtained from asymptomatic patients to identify colonization before clinical infection develops, enabling earlier implementation of precautions.
Question 6: Carbapenem-resistant Enterobacterales (CRE) are considered particularly dangerous because:
- They spread only via airborne routes
- They produce toxins similar to C. difficile
- Treatment options are extremely limited due to resistance to last-resort antibiotics (Correct answer)
- They form spores that survive standard disinfection
Correct answer: Treatment options are extremely limited due to resistance to last-resort antibiotics
CRE are resistant to carbapenems, which are considered last-resort antibiotics, leaving very few effective treatment options and resulting in high mortality rates.
Question 7: Which anatomical site is MOST commonly used for MRSA decolonization therapy?
- Axilla
- Groin
- Anterior nares (Correct answer)
- Oropharynx
Correct answer: Anterior nares
The anterior nares (nostrils) are the primary reservoir for MRSA colonization, making intranasal mupirocin the standard site for targeted decolonization therapy.
CBIC Multidrug-Resistant Organisms 1
Which of the following is the primary route of transmission for Methicillin-resistant Staphylococcus aureus (MRSA) in healthcare settings?