CBIC Multidrug-Resistant Organisms 2 — Questions and Answers
Question 1: When implementing an MDRO prevention bundle, which intervention has the STRONGEST evidence for reducing MRSA transmission?
- Universal gowning and gloving of all staff
- Routine environmental cultures of patient rooms
- Contact precautions combined with hand hygiene compliance (Correct answer)
- Weekly screening of all healthcare workers
Correct answer: Contact precautions combined with hand hygiene compliance
The combination of contact precautions and high hand hygiene compliance has the strongest evidence base for reducing MRSA transmission in healthcare settings.
Question 2: Cohorting MDRO-positive patients is BEST defined as:
- Discharging patients with MDROs to long-term care facilities
- Grouping colonized or infected patients together and assigning dedicated staff (Correct answer)
- Placing patients in negative pressure isolation rooms
- Restricting MDRO-positive patients to their rooms at all times
Correct answer: Grouping colonized or infected patients together and assigning dedicated staff
Cohorting involves grouping patients with the same MDRO together in designated areas and assigning dedicated nursing staff to prevent cross-transmission to MDRO-negative patients.
Question 3: Which of the following is a recognized independent risk factor for acquiring an MDRO in healthcare settings?
- Young age under 18
- Female sex
- Prior exposure to antimicrobial agents (Correct answer)
- Living in a rural area
Correct answer: Prior exposure to antimicrobial agents
Prior antimicrobial exposure is a well-established independent risk factor for MDRO acquisition, as antibiotics can eliminate susceptible flora and allow resistant organisms to proliferate.
Question 4: The vanA gene in VRE confers resistance to vancomycin by:
- Pumping vancomycin out of the bacterial cell
- Modifying the peptidoglycan target to reduce vancomycin binding (Correct answer)
- Producing an enzyme that degrades vancomycin
- Reducing cell membrane permeability to vancomycin
Correct answer: Modifying the peptidoglycan target to reduce vancomycin binding
The vanA operon encodes enzymes that alter the terminal peptidoglycan precursor from D-Ala-D-Ala to D-Ala-D-Lac, dramatically reducing vancomycin's binding affinity.
Question 5: When a patient on contact precautions for MRSA requires transfer to another unit, the infection preventionist should ensure:
- The patient is bathed with chlorhexidine immediately prior to transfer
- The receiving unit is notified before the transfer occurs (Correct answer)
- A negative surveillance culture is obtained before transfer
- The patient wears a gown and mask during transport
Correct answer: The receiving unit is notified before the transfer occurs
Communicating MDRO status to the receiving unit before transfer allows staff to prepare appropriate precautions, preventing a gap in infection control measures.
Question 6: Which disinfectant class is MOST effective against VRE on environmental surfaces?
- Quaternary ammonium compounds (QUATs) alone
- EPA-registered hospital disinfectants including bleach-based products (Correct answer)
- Isopropyl alcohol 70%
- Hydrogen peroxide 3%
Correct answer: EPA-registered hospital disinfectants including bleach-based products
EPA-registered hospital disinfectants, including sodium hypochlorite (bleach)-based products, are effective against VRE; some QUAT formulations have shown reduced efficacy against VRE.
Question 7: A hospital sees a sudden increase in CRE cases. The FIRST step in the infection prevention response should be:
- Close the affected unit immediately
- Conduct a line listing and review epidemiologic data to identify a common source (Correct answer)
- Implement universal contact precautions hospital-wide
- Require all patients to be screened with rectal swabs
Correct answer: Conduct a line listing and review epidemiologic data to identify a common source
The first step in any potential outbreak is to confirm the increase is real, create a line listing, and analyze epidemiologic data to generate hypotheses about the source or mode of transmission.
CBIC Multidrug-Resistant Organisms 2
When implementing an MDRO prevention bundle, which intervention has the STRONGEST evidence for reducing MRSA transmission?