Infection Control: Chain of Infection Flashcards

1
Q

What are the elements required for an infection to develop?

A
  • An infectious agent (pathogen)
  • A reservoir for pathogen growth
  • A portal of exit from the reservoir
  • A mode of transmission
  • A portal of entry to a host
  • A susceptible host
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What must occur for an infection to develop?

A
  • The chain of infection must remain intact with all elements present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can nurses prevent infections?

A
  • Follow infection prevention and control practices
  • Break the chain of infection by eliminating one or more elements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What types of microorganisms can cause infections?

A
  • Bacteria
  • Viruses
  • Fungi
  • Protozoa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are resident microorganisms?

A
  • Permanent residents on the skin
  • Survive and multiply without causing harm
  • Not easily removed by handwashing with plain soap
  • Example: Staphylococcus aureus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are transient microorganisms?

A
  • Attach to skin from contact with people or objects
  • Loosely attached in dirt, grease, under nails
  • Can be readily transmitted without proper handwashing
  • Example: Escherichia coli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What factors determine a microorganism’s ability to cause disease?

A
  • Sufficient number of organisms
  • Virulence (ability to produce disease)
  • Ability to enter and survive in the host
  • Host susceptibility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a reservoir?

A
  • A place where a pathogen can survive but may or may not multiply
  • Examples: Hepatitis A virus in shellfish, Pseudomonas in nebulizers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the most common reservoir?

A
  • The human body (skin, body cavities, fluids, discharges)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is colonization?

A
  • When a pathogen is present on/in the body but does not cause harm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a carrier?

A
  • A person/animal with pathogens that can be transferred but no symptoms
  • Example: Hepatitis B virus carrier
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Other then the body what other reservoirs exist for pathogens?

A
  • Animals, food, water, insects, inanimate objects
  • Example: Legionella in contaminated water systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What conditions allow pathogens to thrive in a reservoir?

A
  • Food, oxygen/anaerobic, water, proper temperature, pH, minimal light
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do microorganisms require for nourishment?

A
  • Organic matter
  • Undigested food in the bowel
  • Carbon dioxide
  • Inorganic materials like soil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What microorganism thrives on organic matter and causes gas gangrene?

A
  • Clostridium perfringens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What microorganism consumes undigested food in the bowel?

A
  • Escherichia coli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do aerobic bacteria require to survive and cause disease?

A
  • Oxygen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which type of organisms cause more infections, aerobic or anaerobic?

A
  • Aerobic organisms cause more infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Give examples of aerobic organisms.

A
  • Staphylococcus aureus
  • Strains of Streptococcus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where are anaerobic bacteria commonly found colonizing?

A
  • The gastrointestinal tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What conditions allow anaerobic bacteria to cause infections?

A
  • If the bowel is damaged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What types of infections are typically caused by anaerobes?

A
  • Deep infections in the pleural cavity, joints, or sinus tracts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Name some diseases caused by anaerobic bacteria.

A
  • Tetanus
  • Gas gangrene
  • Botulism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do most organisms require for survival?

A
  • Water
  • Moisture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Give an example of where microorganisms thrive due to moisture.
- Moist drainage from a surgical wound
26
What form do some bacteria assume to survive without water?
- Spore form
27
What property allows bacterial spores to live without water?
- Spores remain viable when deprived of water - Spores are resistant to drying
28
Name some spore-forming bacteria that can live without water.
- Bacteria causing anthrax - Bacteria causing botulism - Bacteria causing tetanus
29
What temperature range can most pathogens in humans live in?
- 35°C to 37°C
30
Can some microorganisms survive temperature extremes fatal to humans?
- Yes
31
How do cold temperatures affect bacterial growth and reproduction?
- Cold temperatures tend to prevent growth and reproduction of bacteria
32
What pH range do most microorganisms prefer?
- pH range of 5 to 8
33
In what environment do bacteria particularly thrive?
- Urine with an alkaline pH
34
What environment most organisms cannot survive in?
- The acidic environment of the stomach
35
What medications can cause an overgrowth of gastrointestinal organisms?
- Acid-reducing medications like antacids and histamine 2 blockers
36
What condition can gastrointestinal organism overgrowth contribute to?
- Development of nosocomial (hospital-acquired) pneumonia
37
In what environments do microorganisms thrive?
- Dark environments - Under dressings - Within body cavities
38
What type of light may be effective in killing certain bacteria?
- Ultraviolet light
39
Give an example of a bacteria that ultraviolet light can kill.
- Mycobacterium tuberculosis
40
What is a portal of exit?
- The path by which a pathogen leaves the reservoir/host - Necessary for pathogens to enter another host and cause disease
41
What are some examples of portals of exit in the human body?
- Body openings (mouth, nose, rectum, vagina, urethra) - Artificial openings like ostomies - Breaks in the skin (scrapes, cuts, wounds) - Breaks in mucous membranes
42
How are pathogens carried through portals of exit?
- Blood - Body fluids - Excretions (urine, stool, vomit) - Secretions (saliva, mucus, pus, vaginal discharge, semen)
43
Give an example of a pathogen exiting through the respiratory tract.
- M. tuberculosis exits through coughing, sneezing, talking, breathing - Pathogens exit artificial airways like tracheostomies
44
Give an example of a pathogen exiting through the urinary tract.
- Microorganisms from a urinary tract infection exit during urination - Microorganisms exit through urinary diversions like ileal conduits, urostomies
45
How can microorganisms be transmitted from the reservoir to the host?
- Through various modes of transmission - A microorganism may transmit through multiple modes
46
Give examples of microorganisms that can spread by airborne route.
- Measles virus - Varicella-zoster virus (chickenpox) - Mycobacterium tuberculosis (tuberculosis) - Influenza viruses - Severe acute respiratory syndrome coronavirus (SARS-CoV) - Middle East respiratory syndrome coronavirus (MERS-CoV) - SARS-CoV-2 (COVID-19 virus) - Rubella virus - Adenoviruses - Aspergillus fumigatus fungus - Coccidioides immitis fungus - Certain types of meningitis bacteria like Neisseria meningitidis - Smallpox virus - Anthrax spores
47
Give examples of microorganisms that can spread by direct route.
- Staphylococcus aureus - Clostridium difficile - Norovirus - Hepatitis B virus - Human immunodeficiency virus (HIV)
48
What is a major mode of transmission in healthcare facilities?
- Indirect contact - Healthcare workers' hands can pick up and transmit microbes
49
What objects can be modes of indirect pathogen transmission?
- Any object in the environment like stethoscopes or thermometers - Some organisms like C. difficile can live on surfaces for months
50
What groups must follow practices to minimize infection spread?
- All healthcare workers providing direct care or support services - Each group follows procedures for handling patient equipment/supplies
51
Give an example of how respiratory therapists prevent transmission.
- Perform hand hygiene before working with each patient - Properly dispose of contaminated therapy equipment
52
How do invasive diagnostic procedures increase infection risk?
- Provide avenues for pathogen spread - Example: Cystoscopy to visualize the bladder
53
What must all healthcare workers do to prevent patient infection?
- Be conscientious about infection control practices - Perform proper hand hygiene - Ensure equipment is adequately cleaned/disinfected/sterilized
54
What is contact transmission & provide examples?
- Transfer of microbes by physical touch - Can be direct contact, indirect contact, or droplet - Examples: Clostridioides difficile, Staphylococcus, herpes simplex virus, MRSA, VRE, CPO, Ebola
55
What is direct contact transmission & provide examples?
- Physical skin-to-skin contact between infected/colonized person and susceptible host - Examples: Clostridioides difficile, Staphylococcus, herpes simplex virus, MRSA, VRE, CPO, Ebola
56
What is indirect contact transmission & provide examples?
- Contact between susceptible host and contaminated object - Examples: Clostridioides difficile, Staphylococcus, RSV, Pseudomonas, MRSA, VRE, CPO
57
What is droplet transmission & provide examples?
- Large respiratory droplets propelled up to 2m, deposited on susceptible host - Examples: Influenza virus, rubella virus, RSV, coronavirus, Neisseria meningitidis
58
What is airborne transmission & provide examples?
- Small airborne droplet nuclei remain suspended in air, transmitted long distances - Examples: M. tuberculosis, varicella-zoster virus, coronavirus, measles virus
59
What is vehicle transmission & provide examples?
- Single contaminated source transmits to multiple hosts, can cause outbreaks - Examples: Pseudomonas (water, meds), E. coli (food, water), Enterobacter (IV fluids), Salmonella (food)
60
What is vectorborne transmission & provide examples?
- Insects or pests transmit microbes to humans - Examples: Vibrio cholerae, P. falciparum (malaria), West Nile virus, Lyme disease
61
What are some portals of entry for organisms into the body?
- Body openings (mouth, nose, rectum, vagina, urethra) - Breaks in the skin (cuts, scrapes, wounds) - Breaks in mucous membranes
62
Give an example of how organisms can enter through the skin.
- When a needle pierces the skin - As long as the device remains, more organisms can enter
63
How can organisms enter through a urinary catheter?
- Any obstruction to urine flow allows organisms to travel up the urethra
64
What factors enhance the chances of pathogens entering the body?
- Factors that reduce the body's defenses - Breaks in the skin or mucous membrane barriers (cuts, wounds, invasive procedures) - Compromised immune system (due to conditions like HIV/AIDS, cancer treatment, aging) - Presence of indwelling medical devices (catheters, IV lines) - Poor hygiene practices (lack of handwashing, improper wound care) - Exposure to contaminated surfaces, food, or water - Lack of vaccinations against preventable infectious diseases - Crowded living conditions or high-risk environments (healthcare facilities) - Certain lifestyle factors (smoking, poor nutrition, excessive stress)
65
What determines whether a person acquires an infection?
- Pathogen factors: Virulence, infectious dose, ability to adhere and invade host cells - Host factors: Immune status, age, underlying medical conditions, genetic factors - Environmental factors: Exposure to contaminated sources, hygiene practices, crowding - Route of transmission: Airborne, droplet, contact, vector-borne - Integrity of host defenses: Intact skin/mucous membranes, normal microbiome
66
Why doesn't everyone develop an infection despite constant microorganism exposure?
- An infection only develops when an individual becomes susceptible - To the strength and numbers of microorganisms capable of causing infection
67
How does organism virulence affect susceptibility?
- The more virulent an organism, the greater the likelihood of susceptibility
68
Why are antibiotic-resistant organisms becoming more common?
- Believed to be associated with frequent and inappropriate antibiotic use
69
How can a person's resistance to an infectious agent be enhanced?
- By receiving an appropriate vaccine - By actually contracting the disease
70
How can nurses intervene to prevent infections?
- Understand the chain of infection - Observe for signs and symptoms of infection - Take appropriate actions to prevent spread
71
What factors determine the severity of a patient's illness from infection?
- Pathogen virulence - Infectious dose - Route of infection - Host immune system - Age - Underlying conditions - Timeliness of treatment - Extent of the infection - Pathogenicity of the microorganism - Susceptibility of the host/patient
72
What is a localized infection?
- Restricted to a limited area (e.g. wound infection) - Proper care controls spread and minimizes illness - May cause localized symptoms like pain, tenderness
73
What is a systemic infection?
- Affects the entire body instead of just one area - Can be fatal
74
How does the course of infection influence nursing care?
- Nurses administer and monitor antibiotics - Provide supportive therapy like nutrition and rest - Complexity depends on body systems affected
75
How can nurses minimize infection spread?
- Use proper technique (e.g. dressing changes) - Control transmission if they have breaks in skin
76
What are some mechanisms that protect the body against infection?
- Normal body flora inside and outside the body - Defense mechanisms of each organ system - Immune response that neutralizes pathogens and repairs cells
77
What composes the immune system?
- Cells and molecules that help resist disease - Some responses are nonspecific (normal flora, body defenses, inflammation) - Others are specific defenses against particular pathogens
78
What happens if the body's defenses fail?
- An infection can quickly progress to a serious health problem