Infection Control Flashcards
What precautions are required, according to the CDC, when seeing an antibiotic-susceptible pneumococcal pneumonia patient? Standard Contact Droplet Aerosol More than one of the above
Standard
Pneumococcal pneumonia does not require special precautions beyond standard according to the CDC (it is not readily transmissible), but droplet precautions are used in some institutions.
Contact: private room and gowns –> antibiotic-resistant prganisms, chicken pox, SARS
Droplet: private room and MASK/GOGGLES WITHIN 3FT –> Mycoplasma pneumonia, SARS
Aerosol: NEGATIVE PRESSURE private room, N95 mask, notify CDC –> avian flu, TB, measles, chicken pox, small pox, SARS
A 16-year-old boy is brought to the emergency department after a car accident. He has multiple contusions, broken bones, and burns to the upper torso. What method of decontamination would be best to treat a stethoscope (in normal cases a non-critical piece of equipment) being used on this patient? 70% alcohol Iodophor Chlorhexidine Ethylene oxide Benzalkonium chloride
Ethylene oxide
General Feedback:
The skin is compromised in this patient, necessitating a higher level of decontamination than would normally be the case. By the way, you shouldn’t autoclave a stethoscope if you want to use it again. In practice, this would be a situation for a disposable stethoscope. Did you know that nurses clean their stethoscopes more often than physicians and medical students? Something to think about…
- 70% alcohol: must be 70% replace water in cell and denatures proteins, altered solvation
- Iodophor: semi-critical items should be sterilized with high-level disinfectant, except spores; also includes: alcohol and phenolics
- Chlorhexidine: antiseptic for living human tissue; includes ethanol, povidone-iodine/Betadine, and triclosan
- Benzalkonium chloride: disinfectant - removal of most viable organisms to reduce bacterial load; 4ry ammonium
Which patient might you put in a negative pressure room? A patient with measles A patient with 3rd degree burns A patient with meningococcal meningitis A patient with a kidney transplant
A patient with measles - Aerosol precaution
General Feedback:
Infections that put OTHERS at risk due to aerosols require a negative pressure room (keeps the causative agent from ‘escaping’ into the hospital environment). Measles virus is transmitted through aerosols, and is one of the few organisms requiring aerosol precautions. When the patient needs protection from infections (e.g. b and d), a positive-pressure environment is used (keep pathogens OUT). Meningococcal meningitis requires droplet precautions, which do not include isolation in a negative-pressure room.
A 45-year-old man presents with fever. He had been discharged from hospital the previous day. The fever was found to have been triggered by a bacterial infection. Which of the following is the most appropriate description of this infection? Endogenous Nosocomial Community-acquired Exogenous
Nosocomial
General Feedback:
The timeframe between admission/discharge and emergence of symptoms is used as a rule of thumb in determining whether an infection is considered hospital- or community-acquired. The reason is the incubation time between transmission/acquisition of the pathogen and when symptoms are noted. However, realize that some infections can take weeks or months to present, so these wouldn’t fall into this 48h timeframe. Endogenous and exogenous refer to the source of the infection—there isn’t enough information here to determine this.
- Endogenous: from patient
- Exogenous: from hospital, community, etc
A 45-year-old government virologist has been accidentally exposed to smallpox virus after a breach in a secure level 4 laboratory. Which precaution, not part of the standard precaution protocol, would be applied during the observation and treatment of this patient?
Isolation in a room with reduced pressure
Bathing of the patient in benzalkonium chloride
Bathing of the patient in ethylene oxide
Masks within 3 feet of the patient
Hand sanitizing before and after patient contact
Isolation in a room with reduced pressure
Smallpox requires aerosol precautions. One of these is use of a negative-pressure room for isolation. Any bathing protocol would be more effective in preventing transmission by contact, and bathing in ethylene oxide would NOT be a good idea or particulary easy to do (it’s a highly toxic gas…). Masking within 3 ft. is suffcient for pathogens transmitted by droplet, but not aerosols. Hand sanitizing is part of the standard protocol, so this is ruled out by the question (although you would definitely do it).
An isolate submitted for susceptibility testing is reported to be resistant to erythromycin, gentamycin, and tetracycline. If this isolate is a Gram-negative, oxidase-negative, lactose-fermenting, sorbitol non-fermenting rod, what type of precautions should be taken in a health-care setting? Standard plus contact plus droplet Standard plus contact Standard plus aerosol Standard plus droplet Standard only
Standard plus contact
Antibiotic-resistant organisms require contact precautions, even when the causative agent itself might not. In this case, the causative agent is most likely E. coli, which does not have any particular associated precautions beyond standard. But the fact that it is resistant to antibiotics to which it should be susceptible make it different than “regular” E. coli that is in everyone anyways, and thus preventing transmission becomes more important.
- Standard: basic hand washing & hand sanitizing
- Contact: when pathogen transmitted by contact (private room, gown and gloves, ex: surgery protocol) - C. difficile, anitiobotic resistant, chicken pox, SARS
- Droplet: transmitted via large droplets - private rooms, surgical mask/goggles w/in 3 feet - Mycoplasma pneumoniae, flu, SARS
- Aerosol: transmitted by droplet nuclei - negative pressure, N-95 mask, notify Infection Control - avian flu, TB, measles, chicken pox, small pox, SARS
A patient in the ICU develops diarrhea after several days of treatment with a broad-spectrum antibiotic for a severe infection. The causative agent is found to be a Gram-positive, strictly anaerobic rod that produces an enterotoxin (called toxin A) that affects a target host cell’s ability to polymerize actin. The organism is related to pathogens producing toxins that inhibit the release of neurotransmitters. Which of the following interventions will help to prevent transmission of this pathogen to others?
HEPA-filtering room air
Treating all surfaces with benzalkonium chloride
Cleaning a toilet with an isopropanol-based cleaner
Autoclaving bed linens
Using hand sanitizer
Autoclaving bed linens
General Feedback:
Referring to Clostridium difficile (Gram + anaerobe related to those producing botulinum and tetanus toxins). Efficient killing of endospores requires either a high-level disinfectant, such as bleach (sodium hypochlorite solution), or sterilization. Transmission is by contact, so filtering air will not be effective in preventing transmission.
•Quaternary ammonium compounds (b) and alcohols (c, e) are low and intermediate-level disinfectants, respectively, so will not be effective against the endospore form of the organism.
A 63-year-old woman is being artificially ventilated after ingestion of botulinum toxin from improperly canned tomatoes. She was healthy prior to this incident. Three days after intubation, the patient develops a respiratory infection. What terminology best describes the type of infection, and what is the most likely causative agent?
Community acquired; Legionella pneumophila
Community acquired; Enterococcus faecalis
Hospital acquired; Legionella pneumophila
Community acquired; Pseudomonas aeruginosa
Hospital acquired, Enterococcus faecalis
Hospital acquired, Pseudomonas aeruginos
Hospital-acquired Pseudomonas aeruginosa
General Feedback:
Be sure to consider the time frame, which tells you it is a nosocomial or hospital-acquired infection, and then the most likely causative agents of nosocomial pneumonias (in the handout notes).
A 58-year-old man is admitted to the ICU after having a stroke. Six days later, it is noted that his urine is cloudy, and he has become febrile. What are the characteristics of Escherichia coli, the most likely causative agent?
Gram-negative, oxidase-negative, lactose-negative, urease-positive rod
Gram-negative, oxidase-negative, coagulase-positive rod
Gram-negative, oxidase-positive diplococcus
Gram-negative, oxidase-negative, lactose-fermenting rod
Gram-positive, catalase-negative cocci in pairs and chains
Gram-negative, oxidase-negative, lactose-fermenting rod
Escherichia coli is the most common cause of UTI, period, whether catheter-associated, otherwise hospital-associated, or acquired in the community. Don’t forget that you need to recognize the basic bacterial characteristics from here on out!
An infection control committee is discussing protocols related to infections caused by a particular virus. The infectious disease fellow points out that this virus is susceptible to many disinfectants, including alcohol and quaternary ammonium compounds. To what family does the virus in question most likely belong? Picornaviridae Papillomaviridae Reoviridae Herpesviridae Adenoviridae
Herpesviridae
These disinfectants affect enveloped viruses (their membranes make them susceptible; how does each type affect lipid bilayers?). Among the families listed, only herpesviruses are enveloped.
NAKED VIRUSES
DNA: CPR
RNA: PAPP + hene
A 30-year-old man presents to his physician with a dry cough, fever and headache. He admitted to having the cough for over a week. Chest X-ray showed infiltrates but no consolidation. The physician suspected infection with a small, wall-less bacterium. What precaution should be taken with this patient?
Dedicated equipment for the patient
Mask within 3 ft of patient
Admit patient to hospital
Sterilizing all equipment used on the patient
Use of N-95 respiratory mask
Mask within 3 ft of patient
Mycoplasma pneumoniae is one of the few bacteria with no cell wall, and causes a pneumonia characterized by dry cough and interstitial infiltrates (you’ll learn more about this in the respiratory 2 module). It is readily transmissible in droplets, and as such droplet precautions are recommended by the CDC.
What is the most correct term for treating a liquid at 135˚C for 2 s? Pasteurization Ultrafiltration Autoclaving Sterilizing Ultrapasteurization
Ultrapasteurization
General Feedback:
Ultrapasteurization is also know as UHT (ultra-high temperature) pasteurization. The higher temperature used permits a much shorter contact time with the product, and is more efficient in reducing bacterial numbers as compared to traditional pasteurization. While they are not sterile, these reduced numbers permit a much longer shelf-life than pasteurization, especially coupled with aseptic (i.e. sterile) packaging processes.
Pasteurization: reduce number of pathogens; apply 72C for 15-20s
Autoclaving: moist heat; 15-20 min of steam @ 15 psi –> end temp of 121C
Sterilizing: complete removal of pathogens via heat, irradiation (large batches of heat-sensitive material - mainly for vaccines b/c antigenic structure maintained using heat), filtration (decontaminating air and sensitive chemicals (antibiotics)), chemical sterilants (eto, plasma gas, and peracetic acid)
