Pseudomonasspp., particularlyPseudomonas aeruginosa, is acommon waterborne pathogen. Using tap water to rinse suction tubing has been associated withoutbreaks ofPseudomonasinfections.
* From theAPIC Text:
"Water bottles improperly filled with tap water and used for rinsing tracheal suction tubing resulted in an outbreak ofP. cepacia... Tubing permanently attached to showers... implicated in a serious outbreak ofP.
aeruginosabloodstream infection."
References:
APIC Text, 4th Edition, Chapter 117 - Waterborne Pathogens

The correct answer is D, "Peracetic acid," as this agent is appropriate for the disinfection of bronchoscopes.
According to the Certification Board of Infection Control and Epidemiology (CBIC) guidelines, bronchoscopes are semi-critical devices that require high-level disinfection (HLD) to eliminate all microorganisms except high levels of bacterial spores, as they come into contact with mucous membranes but not sterile tissues. Peracetic acid is recognized by the Centers for Disease Control and Prevention (CDC) and the Association for the Advancement of Medical Instrumentation (AAMI) as an effective high-level disinfectant for endoscopes, including bronchoscopes, due to its broad-spectrum antimicrobial activity, rapid action, and compatibility with the delicate materials (e.g., optics and channels) of these devices (CBIC Practice Analysis, 2022, Domain III: Infection Prevention and Control, Competency 3.3 - Ensure safe reprocessing of medical equipment). It is commonly used in automated endoscope reprocessors, ensuring thorough disinfection when combined with proper cleaning and rinsing protocols.
Option A (iodophor) is typically used for intermediate-level disinfection and skin antisepsis, but it is not sufficient for high-level disinfection of bronchoscopes unless specifically formulated and validated for this purpose, which is uncommon. Option B (alcohol) is effective against some pathogens but evaporates quickly, fails to penetrate organic material, and is not recommended for HLD of endoscopes due to potential damage to internal components and inadequate sporicidal activity. Option C (phenolic) is suitable for surface disinfection but lacks the efficacy required for high-level disinfection of semi-critical devices like bronchoscopes, as it does not reliably eliminate all microbial threats, including mycobacteria.
The selection of peracetic acid aligns with CBIC's emphasis on evidence-based reprocessing practices to prevent healthcare-associated infections (HAIs) associated with endoscope use (CBIC Practice Analysis,
2022, Domain III: Infection Prevention and Control, Competency 3.4 - Implement environmental cleaning and disinfection protocols). This choice ensures patient safety by adhering to manufacturer and regulatory guidelines, such as those in AAMI ST91 (AAMI ST91:2015, Flexible and semi-rigid endoscope processing in health care facilities).
References: CBIC Practice Analysis, 2022, Domain III: Infection Prevention and Control, Competencies 3.3 - Ensure safe reprocessing of medical equipment, 3.4 - Implement environmental cleaning and disinfection protocols. AAMI ST91:2015, Flexible and semi-rigid endoscope processing in health care facilities. CDC Guidelines for Disinfection and Sterilization in Healthcare Facilities, 2019.

The Certification Study Guide (6th edition) defines the ventilator utilization ratio (VUR) as a device utilization measure used in surveillance to describe the proportion of patient time during which a specific medical device-in this case, mechanical ventilation-is in use. It is calculated by dividing the total number of ventilator days by the total number of patient days for the same location and time period.
Using the first-quarter data provided, the calculation is as follows:
Ventilator Utilization Ratio = Ventilator Days ÷ Patient Days
Ventilator Utilization Ratio = 800 ÷ 1200 = 0.67
This means that ventilators were in use for 67% of all patient days in the ICU during the first quarter. The study guide emphasizes that device utilization ratios are essential for interpreting device-associated infection data, such as VAP rates, because they reflect the level of patient exposure to the device. Higher utilization increases the population at risk and can influence infection rates independently of prevention practices.
The other answer options are incorrect because they do not reflect the correct calculation. A ratio greater than
1.0 (options C and D) would imply more device days than patient days, which is not possible in this context.
Option A underestimates utilization and does not match the provided data.
Understanding and correctly calculating utilization ratios is a core CIC exam competency, as these metrics support accurate surveillance, benchmarking, and performance improvement efforts.
Reference: Certification Study Guide (CBIC/CIC Exam Study Guide), 6th edition, Chapter 4: Surveillance and Epidemiologic Investigation.

The correct answer is D, "Study," as this is the step in the Shewhart/Deming cycle (commonly known as the Plan-Do-Study-Act [PDSA] cycle) where the results of the interventions are compared with the original goal.
According to the Certification Board of Infection Control and Epidemiology (CBIC) guidelines, the PDSA cycle is a systematic approach to quality improvement, widely used in infection control programs to test and refine interventions. The cycle consists of four stages: Plan (designing the intervention and setting goals), Do (implementing the intervention on a small scale), Study (analyzing the data and comparing outcomes against the original goal), and Act (standardizing successful changes or adjusting based on findings) (CBIC Practice Analysis, 2022, Domain IV: Education and Research, Competency 4.2 - Evaluate the effectiveness of educational programs). The Study phase is critical for assessing whether the intervention achieved the intended reduction in infection rates or other performance metrics, providing evidence to guide the next steps.
Option A (Do) involves the execution of the planned intervention, focusing on implementation rather than evaluation, so it does not include comparing results. Option B (Act) is the final step where successful interventions are implemented on a broader scale or adjustments are made, but it follows the comparison made in the Study phase. Option C (Plan) is the initial stage of setting objectives and designing the intervention, which occurs before any results are available for comparison.
The emphasis on the Study phase aligns with CBIC's focus on using data to evaluate the effectiveness of infection prevention strategies, ensuring that performance improvement projects are evidence-based and goal- oriented (CBIC Practice Analysis, 2022, Domain II: Surveillance and Epidemiologic Investigation, Competency 2.4 - Evaluate the effectiveness of infection prevention and control interventions). This step enables the infection preventionist to determine if the original goal-such as reducing healthcare-associated infections-was met, facilitating continuous improvement.
References: CBIC Practice Analysis, 2022, Domain II: Surveillance and Epidemiologic Investigation, Competency 2.4 - Evaluate the effectiveness of infection prevention and control interventions; Domain IV:
Education and Research, Competency 4.2 - Evaluate the effectiveness of educational programs.

The CBIC Certified Infection Control Exam Study Guide (6th edition) identifies inadequate hand hygiene as the most common and significant factor associated with healthcare-associated transmission of methicillin- resistant Staphylococcus aureus (MRSA). MRSA is primarily transmitted via direct contact, most often through the hands of healthcare personnel after contact with colonized or infected patients or contaminated environmental surfaces.
While MRSA-infected or colonized patients serve as reservoirs for the organism, transmission does not occur unless there is a breakdown in infection prevention practices, particularly hand hygiene. Numerous studies and surveillance findings cited in the Study Guide demonstrate that adherence to hand hygiene protocols- before and after patient contact, after contact with bodily fluids, and after contact with the patient environment-is the single most effective measure to reduce MRSA spread within healthcare facilities.
Improper ventilation (Option A) is associated with airborne pathogens, not MRSA, which is not transmitted via the airborne route. MRSA-colonized healthcare workers (Option D) are far less commonly implicated in transmission than transient hand contamination, and routine screening of staff is not recommended except during specific outbreak investigations. Option B describes a reservoir, not the primary mechanism of transmission.
For CIC exam purposes, this question reinforces a foundational principle of infection prevention: failure to perform appropriate hand hygiene is the leading cause of healthcare-associated MRSA transmission, making it the correct and best answer.