Infection Control/Occupational Health and Safety Flashcards
Who introduced the earliest belief that life was “spontaneously generated” from nonliving matter?
Aristotle
Who used a primitive microscope to observe water and tooth scrapings, and viewed “animalcules”?
Antony van Leeuwenhoek
What did John Tyndall explain?
the need for prolonged heating to destroy microbial life in broth
Who discovered that bacteria existed in heat-stable/sensitive forms? What was the solution?
John Tyndall; intermittent heating, called tyndallization
Who described heat-stable forms of bacteria as endospores?
Ferdinand Cohn
Who reduced the risk of airborne infection during surgery by using carbolic acid?
Joseph Lister
Who is Robert Koch?
- developed the two-part (petri) dishes used for growing bacteria
- provided techniques and discipline necessary to guide future microbiologists
Who is the petri dish named after?
Julius Petri, a German bacteriologist
Who disproved Aristotle’s idea of spontaneous generation of life?
Louis Pasteur
What was the purpose of Pasteur’s swan-neck flask experiment?
To show that microorganisms come from the environment, not spontaneous generation. The S-shaped neck trapped dust and kept the broth sterile.
How did Pasteur’s experiment disprove spontaneous generation?
The broth stayed free of microorganisms until the flask’s top was removed, proving that life does not arise spontaneously but comes from existing microbes.
What is Koch’s Postulates?
A set of criteria that establishes whether bacteria is pathogenic
What are all 4 steps of Koch’s Postulates?
- The microbial agent must be found in every case of disease
- The microorganism must be isolated and grown in pure culture
- The microorganism must cause the same disease when inoculated into a susceptible animal
- The same microbial agent must be recovered from the inoculated animal
Who is the father of microbiology?
Louis Pasteur
What did Louis Pasteur do for the French?
Saved the wine industry by understanding acid-producing bacteria in the vats of wine
Who prepared the first rabes vaccine?
Louis Pasteur
What are the five groups of microorganisms?
bacteria
algae
protozoa
fungi
viruses
Which microorganism have been described as “perfect parasites” because they live inside the cells of a host and replicate quickly?
viruses
What is a host cell?
cells in which invading viruses live and replicat
What is the name of the recently discovered infectious particle? Why is it unique?
Prions; They contain abnormal proteins with no DNA or RNA.
What are Prions responsible for?
A group of chronic diseases with long incubation periods.
What temperature do pathogenic bacteria grow best at?
98.6F (37C)
What are harmless, beneficial bacteria called?
flora
How does bacterial infection occur? What is this known as?
when bacteria that are beneficial for one part of the body invade another part and become harmful, this is known as opportunistic flora
What are the three classifications of bacteria?
based on shape:
1. spherical (cocci)
2. rod (bacilli)
3. spiral (spirochetes)
What is Cocci?
spherical shaped bacteria
reproduce by dividing into two
What does Cocci form as they divide?
chains called streptococci
What are Cocci that form irregular groups or clusters called?
staphylococci
What is Bacilli?
rod-shaped bacteria
What bacteria causes tuberculosis?
Bacilli
What are Spirochetes?
spiral-shaped bacteria
flexible cell walls
capable of movement
What bacteria causes lyme disease and syphilis?
Spirochetes
Who is Hans Christian Gram?
Danish bacteriologist that developed a 4-step staining process for separating bacteria into 2 groups
What are aerobes?
a variety of bacteria that require oxygen to grow
What are Anaerobes?
bacteria that grow in the lack of oxygen and die in oxygen
What are Facultative Anaerobes?
organisms that can grow in the presence of the absence of oxygen
What does Streptococcus mutans (SM) have on its cell wall that protects, and shows capability to cause disease?
a capsule
What microorganism can transform into highly resistant spores?
bacteria
What is the most resistant form of life, what can it be used for?
spores; test effectiveness of sterilization techniques
What are Rickettsiae?
short, nonmotile rods that live in the intestines of insects
How do RIckettsiae spread?
require host cells to reproduce
transmitted to humans through animal bites
What is algae?
single cell or multicell organisms that contain chlorophyll
What ae protozoa?
large group of one-celled organisms that do not have a rigid cell wall that eat bacteria, small algae, and protozoa
Why can some protozoa remain viable outside their hosts for long periods?
cysts outside their hosts for long periods because the thick walls of the cysts make them resistant to drying.
What are fungi?
organisms such as mushrooms, yeasts, and molds that lack chlorophyll
What is a common fungi in the mouth?
Candid, a yeast
What is Oral candidiasis?
a yeast infection that is caused by Candida albicans
Who is susceptible to candidiasis?
very young, very old, very ill, HIV infected patients
What is Oral Candidiasis characterized by?
white membranes on oral mucosa, tongue, and oral cavity
Who discovered Prions?
Dr. Stanley Prusiner while researching neurological disease
What are Prions?
small proteinaceous infectious particles
Composed of DNA or RNA
How did the discovery of prions change how disease was thought of?
showed that proteins can transmit disease, prior it was believed that an infectious agent was made of genetic material
How do Prions work?
convert normal proteins into dangerous ones by changing their shape
What do prions cause?
Fatal diseases, that affect the brain, known as spongiform encephalopathy
What does the CDC recommend to inactivate disease caused by Prions?
placing in sodium hydroxide for 2 hrs
steam sterilization at 121C for 1 hr
How do viruses spread?
virus invades a host cell
replicates
destroys the host cell to release
Why do viruses need specificity for particular cell types to replicate? Examples?
Viruses must have specificity (preference) for particular cell types to replicate because they need to attach to specific receptors on the host cells.
HIV, infect CD4 cells,
Hepatitis, infect liver cells.
How does HIV go from mother to infant? What’s the infection rate?
Some viruses can cross the placenta and infect the fetus. One-fourth of HIV-infected mothers pass the infection to their infants.
What is a viral infection during pregnancy that causes intellectual disability, blindness, and impaired hearing?
cytomegalovirus (CMV)
What is a latent virus?
Establishes a dormant state in host cells, meaning it does not cause immediate symptoms but can be reactivated later.
What is a provirus?
A provirus is a virus that becomes integrated into the nucleic acid of the host cell, allowing it to remain dormant and reactivate later.
What is the treatment plan for viral infections?
treated symptomatically
What are the 6 forms of transmission for viruses?
direct contact
insects
percutaneous injury
blood transfusions
contaminated food/water
droplet inhalation
How can viruses be destroyed in the environment?
chemicals like bleach, iodine, phenal, and formaldehyde
What is Hepatitis A? How can it be stopped?
A virus that can affect anyone
fecal-oral transmission
can be prevented by proper hygiene and vaccine
What is the least serious form of viral hepatitis?
Hepatitus A virus (HAV)
What is Hepatitis B?
a very serious disease that may result in prolonged illness, liver cancer, cirrhosis, liver failure, and death
How is HBV spread?
bloodborne disease that can also be transmitted through other body fluids
What is the percentage of viral hepatitis that HBV is responsible for?
34%
How is Hepatitis C virus (HCV) transmitted, and is there a vaccine available?
HCV is primarily transmitted through blood transfusion or percutaneous exposure to blood.
NO VACCINE
Why is HCV often diagnosed late, and how does it affect the liver?
75% of people infected are unaware, allowing liver damage to progress silently
How has HCV treatment improved over the years?
Before 2011, treatment could take up to a year with only a 40-50% cure rate.
Advances have shorter, injection-free treatments with higher cure rates
What is Hepatitis D?
a defective virus that cannot replicate itself with HBV
What is HDV’s relationship with HBV?
HDV must occur simulataneously with HBV
combined, they are more dangerous than HBV alone
How is HEV spread?
fecal-oral route (contaminated food or water)
Where is HEV usually seen?
epidemics in developing countries
What is HIV?
a blood-borne viral disease where the body’s immune system breaks down
What happens during HIV?
the virus infects special T cells and slowly kills them
What virus causes AIDS?
HIV
What is herpescirus?
a double-stranded DNA virus that causes infection in humans such as herpes, CMV, chickenpox, shingles, mononucleosis, measles, and Kaposi’s sarcome
What are the four major herpesviruses?
Herpes Simplex Virus (HSV 1 and HSV 2)
Herpes/varicella zoster virus (HZV)
Cytomegalovirus (CMV)
epstein-Barr virus (EBV)
What is Herpes Simplex Virus type 1?
a viral infection that causes recurrent sores on the lips also known as fever blisters or cold sores
Where does HSV 1 first appear?
children 1-3 years old that causes pain, increased salivation, halitosis, and swelling
What is the healing duration of HSV 1?
healing begins within 3 days, and lasts 7-14 days
After HSV 1 first appears, what happens? How can it be prevented?
lies dormant and reappears later in life when general resistance is lowered resulting in cold sores, using SPF can reduce sun-induced recurrences
What is the healing process of recurrent herpes sores?
7-10 days no scar
What is HSV 2?
genital herpes, the most common STD in the US
What are the symptoms of HSV 2?
2-10 days after infection symptoms of tingling, iching, and a burning sensation when urinating will appear
When is HSV 2 transmissable?
during the recurrences
If a mother is infected with HSV 2, what is the chance that a newborn is infected too?
50%
If a newborn is infected with HSV 2, what are the chances it will be severely damaged or killed by the virus?
85%
What is HZV?
human herpesvirus type 3 that causes both varicella (chickenpox) and herpes zoster (shingles)
How is HZV transmitted?
through direct contact with skin lesions or through droplet infection from infectious saliva
What portion of HZV causes varicella (chickenpox)?
the primary infection
What portion of HZV causes zoster(shingles)?
the reactivation of the illness
What is CMV?
human herpesvirus type 5 that usually doesn’t cause disease but may infect the fetus causing deafness or intellectual disability
What diseases is EBV responsible for?
infectious mononucleosis
nasopharyngeal cancer
lymphome
oral hairy leukoplakia
What is EBV known as? Why?
Kissing disease: present in saliva
How is herpesvirus transmitted?
through direct contact with lesions or infectious saliva it can spread via saliva or aerosol spray from dental equipment
Is there a vaccine for herpes, and what precautions should be taken?
NO VACCINE
avoiding exposure
wearing protective eyewear
using gloves
What is H1N1, and how is it caused?
a respiratory disease of pigs caused by type A viruses.
How long can an infected person with H1N1 be contagious?
From 1 day before symptoms to 7+ days; longer in children.
How does H1N1 spread from one person to another?
Through droplets or touching contaminated surfaces.
What is Ebola, and how deadly is it?
A rare, not very contagious but deadly virus causing internal and external bleeding, with a fatality rate of up to 90%.
How does Ebola spread?
Through direct contact with infected blood or body fluids like urine, feces, saliva, vomit, and semen.
How is Zika virus transmitted?
Through the bite of an infected Aedes mosquito.
What are common symptoms of Zika? Duration?
Fever, rash, joint pain, and conjunctivitis (red eyes).
up to 7 days
What can Zika cause during pregnancy
birth defects, such as microcephaly
What causes tuberculosis?
The bacterium Mycobacterium tuberculosis.
Why is tuberculosis a high risk for healthcare workers?
It is highly infectious and resistant to disinfectants.
How is tuberculosis used in disinfectant testing?
Its kill time is the benchmark for surface disinfectant effectiveness.
What diseases does Legionella pneumophila cause?
Pontiac fever and Legionnaires’ disease.
Where and how is Legionella pneumophila transmitted?
through aerosolized contaminated water, like lakes, hot tubs, AC,
NOT person-to-person,
What diseases is Legionella pneumophila bacterium responsible for
two acute bacterial diseases:
- Pontiac Fever
- Legionnaires’ Disease
How is Legionella pneumophila bacterium spread?
aerosolization and aspiration of contaminated water
NO PERSON TO PERSON
What is the more and less serious form of Legionella pneumophila bacterium?
Less serious: Pontiac Fever
More serious: Legionnaires’ Disease
What is Tetanus caused by? How does it enter?
a spore-forming bacillus found in soil, dust, or feces
enters through a break in the skin
What is syphilis? Caused by?
an STD caused by Treponema Pallidum Spirochetes
What are the 3 stages of syphilis?
- presence of infectious, ulcerating sore, known as a chancre (resembles herpes, but crust is darker)
- infectious open sore
- latent syphilis, that occurs after 20 years
What is MRSA, and why is it significant?
MRSA (Methicillin-resistant Staphylococcus aureus) is a type of bacteria resistant to some antibiotics, including methicillin.
How has MRSA developed antibiotic resistance?
It evolved due to excessive use of penicillin-type antibiotics.
How common is S. aureus (MSRA) in the general population?
Around 30% of people worldwide carry S. aureus without developing symptoms.
Where are MRSA infections most commonly found on the body?
MRSA infections can occur on the skin’s surface or deeper in the soft tissue, forming a boil or abscess.
What types of places are at higher risk for MRSA infections?
Places with close contact between people, such as schools, dormitories, military barracks, and daycare facilities, are at higher risk.
What are some key prevention tips for avoiding MRSA infections?
Maintain good hand hygiene, avoid squeezing sores, keep wounds covered, and do not share personal items like towels, razors, or clothes.
What are the 6 chain in “The Chain of Infection”
- An infectious agent
- A reservoir
- A portal of exit
- Mode of transmission
- Portal of entry
- A susceptible host
What is bioburden?
organic material such as blood and saliva
What is an infectious agent
a pathogen with sufficient number to cause infection
What is a reservoir? Name Examples
a place where microorganisms normally live and reproduce
humans, animals, water, food, contaminated surfaces, bioburden
How can you minimize the number of reservoirs in the dental setting?
using a dental dam
high-volume evacuation
excellent hand hygiene
thorough cleaning of contaminated surfaces
What is a portal of entry? Name examples.
a means of entering the body
airborne pathogens - mouth and nose
bloodborne pathogens - blood supply
What is a susceptible host?
a person who is unable to resist infection by a particular pathogen
What is an acute infection?
a short-duration infection with severe symptoms
What is a chronic infection?
where a microorganism is present for a long duration, some for life
What is a latent infection?
a persistent infection in which the symptoms “come and go”
What is an opportunistic infection?
normally non pathogenic organisms, occur in individuals whose resistance is decreased or compromised
What is direct transmission?
person-to-person contact
droplets
body fluids
What is indirect transimission
when pathogens are first transmitted to an object or surface then passed on to another person who touches them
What is airborne transmission?
refers to the spread of disease through droplets off moisture that contain pathogens
What is parenteral transmission?
transmission of pathogens through the breaks in the skin
What is blood-borne transmission?
pathogens carried in blood and body fluids of infected individuals can be transmitted
What is naturally acquired immunity? What is it also known as?
when a person has previously contracted disease and has recovered
What are the two forms of naturally acquired immunity?
Active immunity: when the host is involved
Passive immunity: antibodies from an outside source
What is artificially acquired immunity? Examples?
when the body has not been exposed to a disease, it has not developed antibodies and is completely defenseless
Immunization/Vaccination
What are the main routes from patient to dental team
Direct contact: patient’s blood or saliva
Droplet infection: mucosal surfaces
Indirect contact: contaminated surfaces/instruments
How can droplet infection occur in a dental setting?
occurs when a dental team member inhales droplets from the handpiece or air-water syringe
What are some infection control measures to prevent disease transmission in patient to dental team?
wearing gloves
practicing handwashing
using masks
applying rubber dams
using patient mouth rinses
How can team-to-patient disease transmission occur in a dental setting?
While unlikely, it can occur if the member has lesions or cuts while inside the patient’s mouth
What is the primary way patient-to-patient transmission can occur?
occurs when contaminated instruments used on one patient are transferred to another patient
What infection control measures help prevent patient-to-patient transmission?
instrument sterilization
surface barriers
handwashing
gloves
sterile instruments
How does Dental-to-community infection occur?
contaminated impressions sent to labs
contaminated equipment sent for repairs
contaminated members
How does Community-to-dental-to-patient infection occur?
municipal water that colonize the inside of the dental unit waterlines
patient can swallow contaminated water
What should be used, liquid or bar soap?
liquid as bar may transmit transmission
What are the proper steps for hand hygiene when using gloves?
- Wash your hands before putting on gloves.
- Dry your hands thoroughly to prevent bacterial growth.
- Put on gloves, ensuring they are intact.
- After glove use, carefully remove them to avoid contamination.
- Immediately wash your hands again after removing gloves
How should you choose the type of PPE to wear? What materials?
the anticipated exposure to infectious materials
fluid-resistant material
What is a mask worn for?
worn over the nose and mouth to protect from inhaling infectious organisms spread by aerosol of dental tools
What type of mask should be worn when splash or spatter is likeyl?
a mask with 95% filtration efficiency for particle 3-5 micrometers
What are the two most common types of masks?
dome-shaped and flat
Why is protective eyewear worn?
to protect the eyes against damage from aerosolized pathogens and flying debris that could cause blindness
If you wear prescription glasses or lenses what must be added to protective eyewear?
protective side and bottom shields
If you leave the chairside for any reason what should be used in addition to gloves?
overgloves
What are the most common gloves used in patient care?
latex/vinyl examination/procedure gloves
What are overgloves also known as, and what are they made of?
food handler gloves
lightweight, cheap, clear plastic
When are sterile gloves worn?
hospital operating rooms: when invasive procedures, like cutting of bone or significant amounts of blood/saliva are present
When are utility gloves worn?
- When the treatment room is cleaned and disinfected
- While contaminated instruments are being cleaned
- Surface cleaning and disinfection
How can you eliminate cross-contamination when using gloves?
anticipate tools needed during each procedure
use tongs/forceps to open cabinets or drawers
What are the 3 common types of allergies to latex?
Irritant Dermatitis = Surface
Type I and IV = Immune
What is irritant dermatitis, and what causes it?
a nonimmunologic skin reaction caused by contact with substances that produce chemical irritation
What factors contribute to irritant dermatitis?
Frequent hand washing
incomplete rinsing of soaps
cornstarch in gloves
excessive perspiration
failure to dry hands properly
What is the most common latex allergy
Type IV
What is Type IV latex allergy, what causes it?
a delayed contact reaction that involves the immune system, caused by the chemical used to process the latex
NOT PROTEINS
Why should latex gloves never be worn when handling chemicals
chemicals can pass through latex and cause irritation that may be mistakenly identified as allergic reaction
What is the most serious latex allergy that may cause death?
Type I
What causes Type I latex allergy?
A response to the proteins found in latex
What 3 groups should waste be separated into?
general waste
hazardous waste
Infectious waste
What is hazardous waste?
items that are a threat to humans and the environment
What is infectious waste?
items that are capable of transmitting an infectious disease
What are the three types of infectious waste?
blood and blood-soaked
pathologic
sharps
What CDC Guideline divided environmental surfaces into housekeeping and clinical contact surfaces?
CDC Guidelines for Infection Control in Dental Healthcare Settings - 2003
What are housekeeping surfaces?
floors, walls, and sinks
What are clinical contact surfaces?
areas directly contaminated during dental procedures or by the dental team’s gloved hands
What should clinical contact surfaces be divided into?
- touch
- transfer
- splash, spatter, and droplet
What are “touch” clinical contact surfaces?
directly touched and contaminated
handles, pens
barrier protected or cleaned between patients
What are “transfer” clinical contact surfaces?
not directly touched, but are touched by contaminated instruments
barrier protected or cleaned between patients
When should “splash, spatter, and droplet” clinical contact surfaces be cleaned?
daily
When and how should the HVE be cleaned?
What should NEVER be used?
at the end of the day
by flushing a detergent or water-base-detergent-disinfectant
NEVER USE BLEACH (sodium hypchlorite)
What are clinical instruments?
items that are used to penetrate soft tissue or bone
How should critical instruments be sterilized?
since they have the greatest risk of transmission, heat should be used to sterilize
What are semi-critical instruments?
instruments that touch the mucous membrane or non-intact skin
How should you sterilize semi-critical instruments?
using heat or high-level disinfection
What are noncritical instruments?
Only contact intact skin
How should noncritical instruments be cleaned?
using an EPA-registered intermediate-level or low level after each patient
Where should the instrument-processing/sterilization be located in the dental office?
centrally, to allow easy access from all patient care areas
What does the ideal instrument processing area look like?
- dedicated to instrument processing
- should be physically separated from the operatories and dental lab
- should not be part of a common walkway
What are the 3 ways an instrument may be cleaned?
handscrubbing, ultrasonic cleaning, or instrument washing machines
