Microbiology and Infection Control. Chapters 18, 19, 20, 22. Test 1

Question 1

The name of intermittent, or fractional, sterilization.

Answer 1

Tyndallization. Killed both forms: heat-stable and heat-sensitive forms.

Question 2

Resistant, dormant structures formed inside of some bacteria that can withstand adverse conditions.

Answer 2

endospores (the heat-stable form)

Question 3

Infection occurs when bacteria that occur naturally in one part of the body invade another part of the body and become harmful. When this occurs, normal flora is considered…

Answer 3

an opportunistic infection or causing infection. For example, a urinary tract infection called cystitis is caused by contamination with Escherichia coli, a bacterium found in normal flora in the intestine.

Question 4

Bacteria can be seen to have three shapes:

Answer 4

1. spherical (cocci)
2. rod (bacilli)
3. spiral (spirochetes)

Question 5

Cocci (singular, coccus). Characteristics

Answer 5

Cocci reproduce by dividing into two.

Cocci that form chains as they divide are called streptococci (strep throat, tonsilitis, pneumonia, and endocarditis).

Cocci that form irregular groups or clusters are called staphylococci (boils and other skin infections, endocarditis, and pneumonia).

Question 6

Bacilli (singular, bacillus). Characteristics

Answer 6

Bacilli are rod-shaped bacteria. Tuberculosis is a disease that is caused by a bacillus.

Question 7

Spirochetes. Characteristics

Answer 7

Spirochetes are spiral-shaped bacteria that have flexible cell walls and are capable of movement. Lyme disease (from biting by a tick) is caused by a spirochete. Syphilis is also caused by a spirochete.

Question 8

Gram stain characteristics and classification

Answer 8

Four-step staining process that requires the sequential use of a crystal violet dye, iodine solution, alcohol solution, and safranin dye.

Gram positive - Bacteria’s wall cell appear dark purple.
Gram negative - Bacteria’s wall cell appear pink to red.
Gram variable - bacteria that are not consistently stained (for example, Mycobacterium tuberculosis).

Question 9

capable of causing serious disease

Answer 9

virulent. it is a bacteria with a protective coating. Streptococcus mutans, which causative factor in dental caries, forms such a capsule. So they have ability to resist the body’s defense mechanism and antibiotic.

Question 10

Some viruses establish a latent (dormant) state in host cells. The virus becomes integrated into the nucleic acid of the host cell and is known as

Answer 10

a provirus

Question 11

Viral diseases are transmitted by:

Answer 11

1. direct contact
2. insects
3. percutaneous injury
4. blood transfusions
5. contaminated food or water
6. inhalation of droplets expelled by coughing or sneezing.

Question 12

Rickettsiae. Characteristics

Answer 12

Rickettsiae are short, nonmotile (non-movable) rods that normally live in the intestinal tract of insects such as lice, fleas, ticks, and mosquitos. Like viruses, these organisms are very small and require host cells to reproduce.
Disease caused by rickettsia include typhus and Rocky Mountain spotted fever. These diseases are transmitted to humans through the bite of infected insects.

Question 13

Which types of hepatitis are spread by exposure to blood?

Answer 13

hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV).
Note: Hepatitis A virus (HAV) and hepatitis E virus (HEV) are spread by exposure to fecal.

Question 14

A double-stranded DNA virus that causes infection in humans such as herpes, CMV, chickenpox, shingles, mononucleosis, measles, and Kaposi’s sarcoma is

Answer 14

a herpesvirus

Question 15

Four major herpes viruses:

Answer 15

1. Herpes simplex virus (HSV):
   - type 1: oral lesions. Also known as fiver blisters or cold sores. Heal by themselves in 7 to 10 days.
   - type 2: genital lesions. The most common sexually transmitted disease (STDs). Initial symptoms: 2 to 10 days after infection.
2. Herpes zoster virus (HZV). type 3: zoster, shingles, and chickenpox. Chickenpox is the primary infection, and zoster represents reactivation of the illness.
3. Cytomegalovirus (CMV). type 5: normally latent, may become active when the immune system is damaged; highly contagious and is transmitted through most body fluids. Can infect the fetus, in some cases, infants are born deaf or intellectually disabled. The route of transmission of CMV is unclear.
4. Epstein-Barr virus (EBV). type 4: mononucleosis and Burkitt’s lymphoma (a malignancy of the lymph tissues). Primarily ages: 15 and 20 years. Present in the saliva, transmitted by kissing; often called the “kissing disease”.

Question 16

Major groups of microorganisms:

Answer 16

1. bacteria
2. protozoa
3. fungi
4. viruses

Additional groups:
5) rickettsia
6) algae

Question 17

The most common STD in the United States can cause health problems that includes genital warts and cancer

Answer 17

Human papillomavirus (HPV). Can cause cancer of cervix, vulva, vagina, penis and anus. It can also cause oropharyngeal cancer in the back of the throat, tonsils, and tongue. HPV causes 70% of the oropharyngeal cancers in the United States. To prevent the spread of HPV the vaccination is recommended at the age of 11 or 12.

Question 18

Form of swine influenza virus

Answer 18

H1N1 (swine flu). Infected people may be contagious 1 day before symptoms appear and for to 7 days or longer. Spreads very easily from person to person. Can be spread when a person touches something that is contaminated with the virus (droplets from the cough or sneeze) and then touches the eyes, nose, or mouth before washing hands.

Question 19

rare but deadly virus that causes bleeding inside and outside the body

Answer 19

Ebola. The disease kills up to 90% of people who are infected. It is spread through direct contact (broken skin or mucous membranes) and body fluids (urine, feces, saliva, vomit, and semen). It is not spread from the air, water, or food. A person infected with Ebola is not considered contagious until symptoms appear. Any person within 21 days from West African (Liberia, Sierra Leone, or Guinea) may be at risk.

Question 20

A virus that is spread to people primarily through the bite of an infected Aedes species mosquito,

Answer 20

Zika. The most common symptoms: fever, rash, joint pain and conjunctivitis (red eyes) [kənʤʌŋktɪˈvaɪtɪs]. Can be spread from a pregnant woman to her fetus. Can causes microcephaly - abnormal smallness of the head, a congenital condition associated with incomplete brain development. Also, can cause absent or poorly developed brain structures, defects of the eye, hearing deficits, and impaired growth. There is no vaccine to prevent Zika infection.

Question 21

What tissues are affected by the west Nile virus?

Answer 21

It affects a person’s nervous system, causing inflammation of the brain and spinal cord. Caused by mosquitos

Question 22

Legionnaires disease. Characteristic. Types.

Answer 22

The Legionella pneumophila bacterium. No person-to-person involved. It has been found to thrive in lakes, creeks, hot tubs spas, air conditioning system, and the biofilm in dental unit waterlines.
Two types form:
1. Pontiac fever. A less form flu-like with headache, high fever, dry cough, chills, diarrhea, chest pain, and abdominal pain.
2. Legionnaires disease. Causes very serious pneumonia.

Question 23

Tetanus [ˈtetənəs]. Characteristic.

Answer 23

Also known as lockjaw. This is extremely dangerous and often fatal disease that is caused by a spore-forming bacillus found in soil, dust, or animal or human feces. It is introduced into the body through a wound or a break in the skin. Severe muscle spasms and rigidity. The disease can be prevented by the administration of a vaccine; however, immunity must be kept current through booster doses.

Question 24

Syphilis. Characteristic. Stages.

Answer 24

Caused by Treponema pallidum spirochetes.
Stage: 1. The first stage. When it occurs on the lip, it may resemble herpes but the crusting is darker. Painless ulcerating sore, known as a chancre.
2. Second stage. Signs:
- split papules at the corners of the mouth.
- grayish-white, moist, “mucous patches” on the tongue, roof of the mouth, tonsils, or inner surface of the lips (highly infectious).
- measles-type rash, pox-like pustules , hair falling out of the scalp.
3. The third stage, known as latent syphilis, usually fatal, may occur after the disease has been dormant for 20 years.

Question 25

Methicillin-resistant Staphylococcus aureus. Characteristic.

Answer 25

Referred to as MRSA. Staphylococcus aureus (known as staph) is a common bacterium that is carried on the skin or in the nose of healthy people. This type of S. aureus has evolved through the excessive use of penicillin antibiotics, including methicillin over the years. Can occur on the surface of the skin or may go into the soft tissue and form a boil or abscess.

Question 26

Prions. Characteristic.

Answer 26

Prions are defined as “small proteinaceous infectious particles”.
Composed entirely of proteins that lack nucleic acids (DNA or RNA). Can self-replicate.
Prions convert normal protein molecules into dangerous ones simply by causing the normal ones to change their shape. Potentially caused by eating infected food. Prions attack the nerve cells and produce neurodegenerative brain disease or “mad cow” disease. Prion disease are usually rapidly progressive and always fatal.
Type of human disease is Creutzfeldt-Jacob disease. It is rare chronic brain disease with onset in middle to late (40 to 60 years).
Sterilization instruments: sodium hydroxide for 2 hours, followed by steam sterilization at 121 C.
There is no treatment or vaccine.

Question 27

What microorganism causes oral candidiasis?

Answer 27

It is caused by the yeast Candida albicans.

Question 28

What microorganisms is used as the benchmark for the effectiveness of a surface disinfectant?

Answer 28

bacterium M. tuberculosis

Question 29

The links in the chain of infection are…

Answer 29

1. an infection agent (pathogen)
2. reservoir
3. a portal of exit
4. a mode of transmission
5. a portal of entry
6. susceptible host

Question 30

Parenteral means…

Answer 30

through the skin, as with cuts or punctures (needle stick injuries and so on).

Question 31

Immunity types:

Answer 31

present at birth - inherited immunity.
during a person’s life - acquired immunity.

Naturally acquired immunity:
- Active immunity: through disease and recover.
- Passive immunity: during pregnancy, the fetus receives antibodies from the mother’s placenta, and also from the mother’s breastfeeds.

Artificially acquired:
- immunization
- vaccination

Question 32

Infection control measures that prevent disease transmission from the patient to the dental team member

Answer 32

1. gloves
2. handwashing
3. masks
4. face shield and goggles
5. hair covering
6. dental dams
7. high-volume evacuation
8. air filters

Question 33

Infection control measures that prevent disease transmission from the dental team to a patient

Answer 33

1. masks
2. gloves
3. face shields and goggles
4. handwashing
5. immunization

Question 34

Infection control measures that prevent disease from patient-to-patient

Answer 34

1. instrument sterilization
2. surface barriers
3. handwashing
4. gloves
5. use of sterile instruments

Question 35

Infection control measures that help prevent organism leaving the dental office.

Answer 35

1. handwashing
2. removal of protective clothing
3. wearing hair covering
4. disinfecting impressions and contaminated equipment before such items leave the office.

Question 36

Utility gloves are worn:

Answer 36

1. When the treatment room is cleaned and disinfected between patients.
2. while contaminated instruments are being cleaned or handled.
3. for surface cleaning and disinfecting.

Question 37

Three common types of allergic reaction to latex:

Answer 37

1. Irritant dermatitis is a nonimmunologic process (does not involve the body’s immune system). It is caused by contact with a substance that produces a chemical irritation to the skin. The skin becomes reddened, dry, irritated, and, in severe cases, cracked.
2. Type IV allergic reaction, the most common type. It may take 48 to 72 hours for red, itchy rash to appear. Reactions are limited to the area of contact and do not involve the entire body. The chemicals used to process the latex in these gloves cause an immune response; the proteins in the latex DO NOT cause it.
3. Type I allergic reaction is the most serious type of latex allergy and can result in death. In response to the proteins in the gloves. A severe immunologic response occurs, usually 2 to 3 minutes after latex allergic contact the skin or mucous membranes.
   Anaphylaxis is the most severe form if immediate allergic reaction. Death results from closure of the airway caused by swelling.

Question 38

Order of putting on/removing PPE

Answer 38

Putting on PPE:
1. Gown
2. Mask
3. Goggles/Face shield
4. Gloves

Removing PPE:
1. Gloves
2. Goggles/Face shield
3. Mask
4. Gown

Question 39

Organization for Safety, Asepsis, and Prevention (OSAP) recommend that clinical surfaces should be classified and maintained under three categories:

Answer 39

1. Touch surfaces are directly touched and contaminated during treatment procedures (dental light handles, chair switches, drawer handles, pens, containers of dental materials and so on).
2. Transfer surfaces may not be directly touched but are in contact with contaminated items and instruments. Transfer surface include instrument trays, and handpiece, air/water syringe and suction receptors, and radiograph equipment.
3. Splash, spatter, and droplet surfaces would be considered housekeeping surfaces,, that are not actually in contact with members of the dental team or contaminated instruments or supplies (Floors, walls, and sink are examples). Should be cleaned at least once day.

Question 40

Blood, saliva, and other body fluids is..

Answer 40

bioburden

Question 41

Which regulation requires the use of surface disinfection?

Answer 41

Occupational Safety and Health Administration (OSHA)

Question 42

Definitions of disinfectant, antiseptic and sterilization. Some concepts

Answer 42

Disinfectant is chemical used to reduce or lower the numbers of microorganisms on inanimate objects. Spores are not killed during disinfecting procedures.

Low-level disinfection - only for housekeeping purposes.
Intermediate-level disinfection - less-resistant organisms such as Hepatitis B virus and HIV.
High-level disinfection - M. tuberculosis.

Antiseptic is a substance for killing microorganisms on the skin.
Disinfectants ad antiseptics should never be used interchangeably because tissue toxicity and damage to equipment can result.

Sterilization - is process that kills all microorganisms.

Question 43

Sporicidal, virucidal, fungicidal, and tuberculocidal

Answer 43

Sporicidal is a product that capable of killing spores.
Virucidal is a product that is capable of killing some viruses.

And so on..

In dentistry, only those products that are registered with the EPA as hospital disinfectants with tuberculocidal claims should be used to disinfect dental treatment area.

If a disinfectant has residual activity, its action continues long after initial application.

Question 44

Disinfectants-intermediate level: Iodophors, Synthetic phenol compounds, sodium hypochlorite

Answer 44

Iodophors are EPA-registered intermediate-level hospital disinfectants with tuberculocidal action. Should be mixed with soft or distilled water. Usually effective within 5 to 10 minutes.

Synthetic phenol compounds are EPA-registered intermediate-level hospital disinfectants with broad-spectrum activity. Can be used on metal, glass, rubbers, or plastic. However, phenols leave a residual film on treated surfaces.

Sodium hypochlorite. Intermediate-level. Fast-acting, economical, and broad-spectrum disinfectant. CDC guidelines no longer recommends this product for use in dental settings as a disinfectants.

Question 45

Disinfectants-Immersion disinfectants, high-level: Glutaraldehyde, Chlorine dioxide, and Ortho-Phthalaldehyde

Answer 45

Immersion disinfectants that ca be used for sterilization. Used for immersion (soaking) of heat-sensitive instruments. The time for sterilization can range from 6 to 30 hours. Inactivate all microorganisms except endospores.

Glutaraldehyde - high-level disinfectant. Times for disinfection range from 10 to 90 minutes. For plastics and other item that cannot withstand heat sterilization (so this disinfectant is liquid sterilant). Treated instruments after this disinfectant should never be used on patient without thorough rinsing with water.

Chlorine dioxide - high-level disinfectant. Can be used as effective rapid-acting, environmental surface disinfectants (3 minutes), chemical sterilants (6 hours). It doesn’t readily penetrate organic debris and must be used with a separate cleaner. So, first clean the surface with a separate cleaner to remove the organic material.

Ortho-Phthalaldehyde - high-level disinfectant. Disinfection within 12 minutes at room temperature. It has very little odor and does not require activation or mixing. Disadvantage: may stain skin and fabrics, the cost, plastics turn a blue-green color when proteins have not been removed.

Question 46

What is the primary role of the EPA in dentistry?

Answer 46

The U.S. Environmental Protection Agency (EPA) is a regulatory agency. The EPA is associated with dentistry in ensuring the safety and effectiveness of disinfectants. Also, it regulates waste materials, such as chemicals and medical waste after they are sent from the dental office to a final disposal site.

Question 47

What is the primary role of the NIH?

Answer 47

The National Institutes of Health (NIH) is part of the Department of Health and Human Services (DHHS). It is the primary federal agency for conducting and supporting medical research.

Question 48

What is the primary role of NIDCR?

Answer 48

The National Institute of Dental and Craniofacial Research (NIDCR) is responsible for carrying out research work for improving the oral, dental, and craniofacial health of the public.

Question 49

What is the responsibility of the PHAC?

Answer 49

Public Health Agency of Canada (PHAC) is the main Canadian federal agency responsible for public health.

Question 50

What is the primary role of the FDA in dentistry?

Answer 50

The U.S. Food and Drug Administration (FDA) is regulates the manufacturing and labeling (gloves, masks, dental unit lights, ultrasonic cleaners, antimicrobial handwashing, mouth rinses, and so on).

Question 51

What is the primary role of the CDC in dentistry?

Answer 51

The Center for Disease Control and Prevention (CDC) is not a regulatory agency (although it is an agency of the U.S. DHHS). It makes recommendations for public health on scientific data of the highest quality. It issued recommendations for the dental profession to prevent the transmission of blood-borne disease. Also, CDC has published guidelines on preventing the transmission of tuberculosis in healthcare settings, including dental offices.