DHA Infection Control & Prevention 2 — Questions and Answers
Question 1: A patient in the ICU develops fever, purulent discharge from a central venous catheter site, and positive blood cultures 5 days after CVC insertion. What is this complication called and what is the primary prevention strategy?
- Catheter-associated urinary tract infection (CAUTI); use silver-coated catheters
- Central Line-Associated Bloodstream Infection (CLABSI); strict aseptic technique and central line bundle (Correct answer)
- Surgical Site Infection (SSI); prophylactic antibiotics
- Hospital-acquired pneumonia (HAP); head-of-bed elevation
Correct answer: Central Line-Associated Bloodstream Infection (CLABSI); strict aseptic technique and central line bundle
This is a CLABSI (Central Line-Associated Bloodstream Infection). Prevention relies on the 'Central Line Bundle': hand hygiene, chlorhexidine skin antisepsis, maximal barrier precautions during insertion, optimal site selection (subclavian preferred), and daily review of catheter necessity with prompt removal.
CLABSI bundle (IHI): 1) Hand hygiene; 2) Chlorhexidine gluconate (2%) for skin preparation; 3) Maximal sterile barrier precautions (gown, gloves, mask, drape); 4) Optimal catheter site (subclavian > jugular > femoral); 5) Daily assessment of line necessity. CLABSI is a key DHA and JCI quality indicator. Zero-tolerance CLABSI programs in Dubai ICUs have achieved significant rate reductions. When CLABSI occurs: remove catheter, blood cultures x2, appropriate antibiotics.
Question 2: According to WHO guidelines on hand hygiene in healthcare settings, what are the 'Five Moments for Hand Hygiene'?
- Before patient contact; before aseptic procedures; after body fluid exposure; after patient contact; after touching patient surroundings (Correct answer)
- Before entering a room; after leaving a room; before meals; after toileting; before procedures
- When hands are visibly dirty; before surgery; after patient death; at shift change; after PPE removal
- Before and after every procedure; at the start and end of each shift; after eating
Correct answer: Before patient contact; before aseptic procedures; after body fluid exposure; after patient contact; after touching patient surroundings
WHO's Five Moments for Hand Hygiene: (1) Before touching a patient, (2) Before aseptic/clean procedures, (3) After body fluid exposure/risk, (4) After touching a patient, (5) After touching patient surroundings. This framework applies to all healthcare settings.
WHO 5 Moments: Moment 1 (before patient contact) — prevents transmission to patient from healthcare worker; Moment 2 (before aseptic procedure) — protects against endogenous and exogenous microorganisms; Moment 3 (after body fluid exposure) — protects HCW and environment; Moment 4 (after patient contact) — protects HCW and environment; Moment 5 (after contact with patient surroundings) — protects HCW and environment. Alcohol-based hand rub preferred unless hands visibly soiled. DHA audits hand hygiene compliance as a key safety metric.
Question 3: A patient is admitted with confirmed MRSA (methicillin-resistant Staphylococcus aureus) pneumonia. What transmission-based precautions should be implemented?
- Standard precautions only
- Droplet precautions (surgical mask, eye protection)
- Contact precautions (gloves, gown) plus standard precautions (Correct answer)
- Airborne precautions (N95 respirator, negative pressure room)
Correct answer: Contact precautions (gloves, gown) plus standard precautions
MRSA primarily spreads by direct and indirect contact. Contact precautions are required: single room or cohorting, gloves and gown for all room entries, dedicated equipment. Standard precautions are always maintained in addition. Airborne precautions are for aerosolized infections (TB, measles, varicella).
Transmission-based precautions: Contact (MRSA, VRE, C. diff, norovirus, scabies) — gloves + gown + single room/cohort; Droplet (influenza, Group A strep, meningococcal, pertussis) — surgical mask within 1-2m; Airborne (TB, measles, varicella, COVID aerosols) — N95 + negative pressure room. MRSA requires contact precautions. Note: C. difficile requires soap and water handwashing (alcohol gel does NOT kill spores). DHA infection control standards align with CDC/WHO guidelines.
Question 4: In the context of sterilization and disinfection, which method achieves the highest level of microbial kill, including all bacterial spores?
- High-level disinfection with glutaraldehyde
- Pasteurization
- Sterilization (steam autoclave or ethylene oxide) (Correct answer)
- Low-level disinfection with quaternary ammonium compounds
Correct answer: Sterilization (steam autoclave or ethylene oxide)
Sterilization is the complete elimination of all microorganisms including bacterial spores. Methods include steam autoclave (121°C/15 psi for 15 minutes or 134°C for 3 min), ethylene oxide gas, hydrogen peroxide plasma, and dry heat. High-level disinfection kills all organisms except some spores.
Spaulding Classification: Critical items (enter sterile tissue/blood) → sterilization required (surgical instruments, implants); Semi-critical (contact mucous membranes) → high-level disinfection minimum (endoscopes, laryngoscopes); Non-critical (contact intact skin) → low/intermediate-level disinfection (stethoscopes, BP cuffs). Sterilization methods: Autoclave (most common, heat/moisture), EtO gas (heat-sensitive items), H2O2 plasma (STERRAD), dry heat (oils/powders). DHA requires adherence to Spaulding classification in all healthcare facilities.
Question 5: An outbreak of gastroenteritis affecting 15 patients in a ward is suspected to be caused by Clostridioides difficile (C. diff). Which measure is critical to stop transmission that differs from standard contact precautions?
- Use of alcohol-based hand sanitizer instead of soap and water
- Use of N95 respirators
- Handwashing with soap and water (not alcohol gel) is mandatory (Correct answer)
- Negative pressure room for all patients
Correct answer: Handwashing with soap and water (not alcohol gel) is mandatory
Clostridioides difficile (C. diff) spores are NOT killed by alcohol-based hand rub. Soap and water handwashing is mandatory for all care of C. diff patients because physical removal and soap can eliminate spores. This is a critical distinction from other contact precautions.
C. diff key facts: spore-forming anaerobe — spores resist alcohol. Soap and water handwashing physically removes spores. Additional measures: contact precautions (gown + gloves), dedicated equipment, sporicidal disinfectant (10% bleach/sodium hypochlorite or EPA-registered sporicidal agents) for environmental cleaning. Avoid proton pump inhibitors and unnecessary antibiotics (risk factors). Antimicrobial stewardship reduces C. diff incidence. Treatment: oral vancomycin or fidaxomicin (metronidazole now third-line).
Question 6: Healthcare workers in Dubai who sustain a needlestick injury from a patient of unknown HIV status should follow which protocol?
- No action needed unless the patient is known HIV-positive
- Immediately start 28-day post-exposure prophylaxis (PEP) in all cases
- Assess source patient risk, report immediately, and start PEP within 72 hours if indicated (Correct answer)
- Wait for HIV test result before deciding on PEP
Correct answer: Assess source patient risk, report immediately, and start PEP within 72 hours if indicated
Needlestick protocol: immediately wash wound, report to occupational health, assess source patient HIV risk (consent for testing if possible), and start PEP within 72 hours if source is HIV+ or high-risk unknown. PEP is most effective when started as early as possible, ideally within 1–2 hours.
Needlestick management (DHA and international guidelines): 1) Immediate first aid — wash with soap and water, do not squeeze; 2) Report immediately to occupational health/supervisor; 3) Source patient assessment — HIV status, hepatitis B/C; 4) PEP decision — if source HIV+ or unknown high-risk: start PEP within 2 hours (max 72 hours), 28-day course (tenofovir + emtricitabine + integrase inhibitor); 5) Baseline and follow-up testing. HBV: check vaccinated HCW immunity; if not immune, give HBIg + vaccine. HCV: no PEP, monitor and treat if seroconversion.
DHA Infection Control & Prevention 2
A patient in the ICU develops fever, purulent discharge from a central venous catheter site, and positive blood cultures 5 days after CVC insertion.
What is this complication called and what is the primary prevention strategy?