Chapter 9 & 10 Flashcards
Living organisms that are too small to be seen with the naked eye
Microorganisms
Examples of microorganisms
bacteria, viruses, fungi, prions and protozoa
Microorganisms that live on or inside the body without causing infections or diseases are referred to as
Normal flora
They aid in skin preservation and digestion and protect us from harmful organisms that can cause infections or diseases
Normal flora
Microorganisms that cause infections and diseases are called
Pathogens
Very small, single-celled organisms with a cell wall and an atypical nucleus that lacks a membrane
Bacteria
a resistant form of the bacterium that is produced within the cell when environmental conditions are unfavorable
Endospores
Can grow independently and replicate without a host cell
Bacteria
Subcellular organisms and are among the smallest known disease-causing organisms. Because of their small size, they must be viewed with an electron microscope
Viruses
A fully developed viral particle
Virion
Needs a host and can mutate quite rapidly, becoming resistant to drugs that were originally effective against them.
Virus
occur as single-celled yeasts or as long, branched, filament-like structures called molds that are composed of many cells
Fungi
It has been difficult to create antiviral drugs that are not also harmful to the host cell. Only a few antiviral agents exist, and these are useful against only a limited number
Viruses
fungi cause skin infections
athlete’s foot, ringworm
Infections caused by usually nonpathogenic organisms
Opportunistic infections
The smallest and least understood of all pathogens
Prion
Do not have DNA or RNA
Prions
Are complex single-celled animals that generally exist as free-living organisms
Protozoa
What is the correct order for the Cycle of Infection
Pathogenic organisms, reservoir of infection, portal of exit, means of transmission, portal of entry, susceptible host
made up of genetic material, either DNA or RNA which is protected by an outer protein coating called capsid.
Virion
how do molds reproduce?
molds reproduce by spore formation
example of prions
mad cow disease
how protozoa classified as:
motile or nonmotile
distinguish pathogens from nonpathogenic organisms and normal flora
Virulence factors
Microorganisms capable of causing disease are called
pathogenic organisms or pathogens
Examples of bacteria
-whooping cough (droplet)
-Tuberculosis (airborne)
-Cystitis (contact)
-Syphilis (sexual contact)
-Gonorrhea (sexual contact)
-wound infection (contact)
-Infectious diarrhea (vehicle, contact)
-Strept throat (droplet)
Examples of Fungus
-Pneumonia, thrush in infants (droplet)
-Ring worm, athletes foot (contact)
Examples of Virus
-Mumps (droplet)
-poliomyelitis (vehicle, contact)
-Genital herpes (sexual contact)
-chicken pox, shingles (contact, airborne)
-measles (airborne)
-fever blisters (contact)
Examples of protozoa
-Amebic dysentery (vehicle, contact)
-Giardiasis (vehicle, contact)
-Malaria (vectors-mosquitos)
Can be resistant through drugs
Virus
Useful fungi
antibiotic, cheese, penicillin
Destructive fungi
ringworm
place where pathogens can thrive in sufficient numbers to pose a threat
Reservoir of infection
Normal flora can cause infections when they are located outside their usual environment or when the hosts immune system is compromised. such infections are called:
Opportunistic Infections
A reservoir of infection environment must have:
-moisture
-nutrients
-suitable temperature
Most common reservoir of infection
Human body
Other examples of nonhuman reservoirs:
-animals (the reservoir for Salmonella)
-soil(the reservoir for Tetanus)
-food (he reservoir for Botulinum)
-water (the reservoir for typhus and Legionnaires’ disease)
Any route through which blood, body fluids, excretions, or secretions leave the body
Portal of exit
Examples of Portal of Exit
-Gi tract
-open wound
-respiratory tract
-Urinary
-bloodstream
Free living organism, such as a parasite
protozoa
Classic example of a carrier of infection is
“typhoid Mary” who was a “healthy” food handler
What is this an example of:
asymptomatic individual infected with HIV who spreads the disease through sexual intercourse or by sharing contaminated needles with intravenous drug users.
carrier of infection
Because some pathogens live in the bodies of healthy individuals without causing apparent disease, a person may be the reservoir for an infectious organism without realizing it. These individuals are called
Carriers
are patients who have a reduced natural resistance to infection.
Susceptible hosts
Also called HAI
Nosocomial infection
-hospital acquired infections
-healthcare associated infections
Nosocomial infection, also called HAI
In addition to the primary problem that caused their hospitalization, they may develop a
Nosocomial infection
The route by which microorganisms gain access into the susceptible host
Portal of energy
examples of portal of entry:
-respiratory tract
-urinary tract
-gi tract
-open wound or break in skin
-mucous membranes of the eyes, nose, or mouth
-bloodstream
Most direct way to break the cycle of infection is to prevent transmission of the infection organism from the reservoir to the susceptible host
Transmission of disease
Six main routes of transmission:
1) direct contact and indirect routes that involves transport of organisms by way of
2) fomites
3) vectors
4) vehicles
5) droplet contamination and
6) airborne
-Infected person must touch susceptible host
-requires the pathogens to be placed in direct contact with susceptible tissues
Direct contact
Examples of direct contact
-syphilis and HIV infections may be contracted when infectious organisms from the mucous membrane
-Also, skin infections often occur among hospital workers because of the frequent contact with patients who have staphylococcal and streptococcal diseases.
An object that has been in contact with pathogenic organisms is called
Fomite
Examples of fomite:
-contaminated urinary catheter
-contaminated gloves
-xray table
-positioning sponges
is anthropoid in whose body an infections organisms develops or multiplies before becoming infectious to a new host.
-transmission occurs when an infected inset bites host.
Vectors
Examples of vectors
mosquitos- malaria
ticks - lyme disease
is any medium that transport microorganisms
vehicle
examples of vehicles:
contaminated food, water, drugs, or blood
Often occurs when an infections individual coughs, sneezes, speaks or sings in the vicinity of a susceptible host
Droplet contamination
Involves contact of the mucous membranes of the eyes, nose, or mouth of a host with large droplets (greater than 5 micrometers) that contain microorganisms
Droplet contamination
how far do droplets travel
not far - 3 feet or less
most common nosocomial infections
UTI
Examples of droplet contamination:
-influenza
-meningitis
-diphtheria
-pertussis
-streptococcal pneumonia
Occurs from dust that contains spores or droplet nuclei
Airborne Transmission
Are defined as particles of evaporated droplets containing microorganisms and measures 5 micrometers or smaller in diameter
Droplet nucleis
examples of airborne infections:
-tuberculosis
-rubeola
-varicella viruses (also transmitted via direct contact)
The human body is protected from the invasion of microorganisms in three ways:
-natural resistance and defenses
-acquired resistance (also known as active immunity)
-short term passive immunity
provided by mechanical barriers of intact skin and mucous membranes
Natural Resistance
Occurs when an individual develops antibodies to a particular organisms as a result of either infection or immunization
Acquired Immunity (long term)
Occurs following an injection of performed antibodies to a particular infection
passive immunity
Inflammation increases blood flow to the site and permits the passage of fluids and white blood cells into the tissues to engulf and destroy the invading pathogens. This process is called
phagocytosis.
for natural resistance what is the first level of defence?
Skin
Further information from textbook:
The mucous membranes of the respiratory, urinary, gastrointestinal, and reproductive systems secrete mucus, which traps foreign particles. Additionally, the respiratory tract is lined with cilia that transport mucus-containing dust and microorganisms out of the body.
Chemicals, such as lysozyme in human tears and acids produced by the stomach, vagina, and skin, also help destroy invading microorganisms.
This state of being resistant to a specific infection is called
acquired immunity
Acquired immunity occurs because the body is able to distinguish itself from foreign protein substances that enter the body. These substances are called
antigens
are protein substances formed in response to specific antigens.
antibodies
Short term or longer term:
Acquired
Passive
Acquired- long term
passive - short term
example of passive immunity
Newborns are temporarily immune to infections because of the antibodies that are passed from mother to fetus in utero. Infants will continue to receive this passive immunity if breastfed after birth. Because the body does not produce these antibodies, passive immunity is short term.
Difference between active and passive immunity
Active or acquired immunity occurs when individuals develop their own antibodies to a specific antigen as a result of having the disease or being immunized against it. This resistance is long term. Passive immunity occurs when individuals receive antibodies produced outside their bodies, such as those from the mother that exist in the newborn, or those produced in a laboratory for emergency immunization. This resistance is short term.
An infectious disease or condition that affects many people at the same time in the same geographic area
Epidemic
Monitors and studies the types of infections occurring in the nation, compiles statistical data about these infections, and publishes this information in both a weekly report and an annual surveillance summary report
Centers for Disease Control (CDC)
Studies, collects, and compiles infection data from every country in the world and makes this information available worldwide
The World Health Organization (WHO)
The most complete source of information about infectious diseases in the United States
CDC
Emerging diseases are:
-new diseases appearing in the population
-existing ones that are rapidly increasing in incidence or geographic range
-resurgent or recurrent old diseases caused by an old or mutated pathogen
Disease emergence is precipitated by many factors:
- Increased human exposure to vectors in nature
- Population growth and migration to crowded cities
- Rapid international travel and transportation of goods
- Contact with new strains of dangerous pathogens
- Pathogen mutation caused by overutilization of antimicrobial agents
- Breakdowns in public health measures
- Climate change
- Bioterrorism
Infectous disease examples are
-Emerging disease
-Healthcare-associated infectious
-Bloodborne pathogens
-Tuberculosis
Widespread epidemic
Pandemic
Hospital-acquired infections are also known as
Nosocomial infections
are defined as those that occur more than 48 hours after being admitted to the hospital
Nosocomial infections
The newer term for nosocomial infection
healthcare-associated infections (HAI)
Typical source of infections of HAIs
- Contaminated hands of health care providers
- Contaminated instruments
- Urinary catheters, ventilators, central lines, and surgical sites, which can allow microbes to gain easy entrance into the body
HAIs that greatly concern health care providers because they are multidrug-resistant
-Methicillin-resistant Staphylococcus aureus (MRSA)
-Vancomycin-resistant enterococci (VRE)
Another type of HAI that is very common in the hospital environment
Clostridium difficile colitis
A gastrointestinal infection that causes diarrhea
-caused by a gram-positive bacillus
-difficult to control because it cannot be eliminated by routine asepsis methods
-patients on antibiotics most susceptible
Clostridium difficile colitis
Bloodborne pathogens include:
-HIV
-AIDS
-Hepatitis
Are the most common cause of transmission from patients to healthcare workers
Needle-stick
Is the bloodborne virus that causes AIDS
HIV
HIV is transmitted by means of:
-Sexual contact
-Contaminaated blood or needles
-Fluids containing blood
-Placental communication from mother to fetus
-Mothers’ milk
Hepatitis a and E are transmitted through
Food and water contaminated with feces
Hepatitis B, C, and D are
bloodborne
There is no vaccine for what type of hepatitis
Hepatitis C
There are vacciones for only which type of hepatitis
Hepatitis A and B
A contagious, airborne
lung disease caused by M.
tuberculosis
Most patients are
homeless, recent
immigrants, or
immunocompromised.
Pre-employment screening
required for healthcare
workers and after known
exposure
Tuberculosis
involving drugs that decrease the body’s normal immune response
immunosuppressant
Diseases for which quarantine is currently authorized
-Cholera
-Diphtheria
-Smallpox
-TB
-Plague
-Yellow fever
-SARS
-Covid -19
refers to an infection control system designed to reduce the risk of transmission of infections from unrecognized sources of bloodborne diseases and from other pathogens in health care institutions.
Universal Precautions “standard precautions”
Expanded protection to all mosit body secretions
Body Substances precautions
Standard Precautions apply to:
- Blood
- All body fluids
- Secretions and excretions (except sweat), regardless of whether they contain visible blood
- Nonintact skin
- Mucous membranes
Current infection-control system
Standard precautions
Standard precautions includes transmission-based precautions for
-Airborne
Published by OSHA in 1991
Occupational Exposure to Bloodborne Pathogens
OSHA Bloodborne Pathogens Standard requires employers to
develop an exposure-control plan for the work site that describes
employee protection measures.
include engineering and work-practice controls to ensure the use of
personal protective clothing and equipment.
provide signs and labels to identify biohazard materials.
provide annual bloodborne pathogen training, hepatitis B
vaccinations, and medical care in the event of occupational exposure.
Involves reducing the probability of infectious organisms being
transmitted to a susceptible individual
Medical Asepsis
The process of reducing the number of organisms
Microbial dilution
Involves the destruction of pathogens by using chemical materials
Disinfection
This involves treating items with heat, gas, or chemicals to make them germ free
Sterilization
Microbial dilution includes
-hand hygiene and other cleanliness measures
-Disinfection
-Sterlization (surgical asepsis)
Washing for 30–60 seconds with soap and water
Alcohol-based rubs
More effective at killing some HAI organisms,
such as C. difficile
More convenient than accessing sinks
Hand Hygiene (sing happy birthday twice)
Cleaning reduces the incidence of airborne infections and the
transfer of pathogens by fomites.
Always clean from the least contaminated area toward the more
contaminated area and from the top down.
Avoid raising dust.
Do not contaminate yourself or clean areas.
After each use, clean all equipment that comes in contact with
patients. Use a cloth moistened with disinfectant.
CDC recommends sodium hypochlorite bleach (Clorox) as an
inexpensive, effective disinfectant for preventing the spread of HIV
Cleaning Techniques
Mix bleach in a 1:10 is
1 part bleach 10 cups of water
Replace linens after each patient.
To dispose of contaminated linens
fold edges to the middle without shaking or flapping.
place loosely balled linens in designated hamper.
Sharps container is proper disposal for needles.
Blood-contaminated items (gauze, bandages) also have
designated “Biohazard” disposal containers.
Handling and Disposal Of Contaminated Items and Waste
Requires two technologists
One has all patient contact.
Other has no patient contact—only handles equipment.
Reduces contamination of equipment, which is difficult to
disinfect completely
When patient is in the department, use sheets to cover table,
wheelchair, etc.
Wear appropriate protective apparel.
Radiography of Isolation Patient
are designed to prevent the spread of infections to compromised patients
Protective precautions
Includes neonates, organ transplants, burn victims, and those
receiving chemotherapy
Older terminology—protective isolation or reverse isolation
May require a modified surgical aseptic technique.
Two radiographers are recommended for imaging procedures.
Precautions for Compromised Patients
