DANB - Infection Control Exam; Standard Precautions and Prevention of Disease Transmission

Why is infection control practiced in dental settings?

to deter transmission and disease development at any point/any direction.

What are the modes of transmission for infectious agents?

patient to dental team, dental team to patient, patient to patient, dental team to community, and community to patient.

Main transmission pathway in patient to dental team?

patients mouth, through direct or indirect contact by droplet infection (inhalation, skin break, mucosal contact) or cuts/punctures.

Main transmission pathway in patient to patient/dental team to community?

mouth through indirect contact; main ways through inanimate contact with bodily fluids.

Main transmission pathway in dental team to patient?

mouth by direct contact through lesions/bleeding or indirectly with instruments. droplet infection occurs through inhalation/contact with mucosal tissues.

main transmission pathway community to patient?

direct contact with contaminated municipal water

What is Infection Controls Main Goal

infection control measures should decrease dose of microorganisms that may be transmitted between people/individuals/surfaces.

End result of exposure dependent on what?

3 interrelated factors:

presence of health/disease = (virulence of infectious agent x its dose)/resistance of host.

Considerations to Office Remodeling/Construction

biggest concerns is potential environmental dissemination of microorganisms resulting in nosocomial infections. construction creates favorable environments for certain microorganisms, crucial to keep work areas isolated from patient care and provisional barriers between the two.

Define nosocomial infection

infections acquired while in hospital/other medical facility.

Special Considerations/Steps for Construction work

contractors responsible for work area cleanliness, areas surrounding need to be cleaned more often. extra precautions for employees/patients needed with certain patients needing to be rescheduled (respiratory problems).

Most common construction related infections

fungi - Aspergillus, bacteria - group A Streptococcus or Pseudomonas

How many steps in Infectious Development

6 steps in development

Steps in Development of Infectious Disease

1: source of microorganism

2: escape route from source (coughing, talking, removal or oral instruments, droplets/aerosols)

3: transmission of agent: direct contact, indirect contact, spray, splatter, inhalation, aerosol)

4: entry route: development through inhalation, ingestion, direct/indirect contact.

5: Virulence/infection: determines severity of infectious pathogen and multiplication in the body

6: susceptible host/causation: compromised immune system can negatively impact response to infection, note cause of harmful body damage

Stages in Infectious Disease

1. incubation stage; time between exposure until symptoms evident.

2. prodromal stage; initial symptoms arise and symptom's progress

3. acute stage; following symptoms when individual becomes sick, the most potential for transmission is now and visits should be rescheduled.

4. convalescent/recovery stage; microbe levels decrease and products deactivated. transmission still possible, during any stage patient may appear asymptomatic.

BloodBorne Disease

any diseases transmitted the blood or other bodily fluids (semen, mother's milk, saliva).

What BloodBorne Diseases are of particular interest in dentistry?

viral hepatitis particularly HBV, HIV developing into AIDS.

What viral hepatitis spreads via Fecal - Oral

Hepatitis A virus, Hepatitis E virus; both not posing risk to dental workers. both include acute onset starting 15 days - several months after exposure.

Hepatitis A Virus (HAV)

non - enveloped single - stranded RNA picornavirus, with acute infections almost never resulting in death. Available vaccine and antibody screening tests .

Hepatitis E Virus (HEV)

non - enveloped, single - stranded RNA calcivirus, with no vaccine or tests detecting anti-HEV, antibody to HEV. contraction during pregnancy can prove fatal.

HIV Transmission

bloodborne disease, transmitted through HIV - positive blood, sexual contact, or mother to child, sharing of needles by drug users, and in saliva.

Blood Transfusions and HIV

screening tests for anti - HIV/other characteristic proteins (p24) make likelihood of exposure through blood transfusions practically nonexistent.

Largest source transmission of HIV

unprotected sexual practices with HIV - positive individual

Systemic Diseases having Oral Lesions

Syphilis, Chickenpox, and Infectious mononucleosis

What causes Syphilis?

spirochete Treponema pallidum

Syphilis signs/symptoms

initially showing up as open ulcer on tongue/lip, being a systemic disease if left untreated can result in secondary patches on mucous membrane in oral cavity 2-10 weeks after initial lesion.

What causes Chickenpox (and Shingles)?

herpes virus type-3/vermicelli zoster virus transmitted by droplet infection to respiratory tract, bloodstream and eventually skin/other organs manifesting as oral vesicles.

What causes infectious mononucleosis?

HHV-4/Epstein - Barr Virus, transmitted by contact with saliva and sometimes through blood transfusions.

Infectious Mononucleosis signs/symptoms

generally fever/fatigue with a number of oral manifestations like, sore throat, oral ulcers, red areas in palate (petechiae), whitish tongue lesions (hairy leukoplakia) and number of cancers.

Bacterial Diseases transmitted Respiratory/Oral Fluids

Pharyngitis, Scarlet Fever, Pneumonia, middle ear infections, meningitis, sinusitis, conjunctivitis, bronchitis, diphtheria, pertussis, tetanus.

What bacteria causes Pharyngitis and Scarlet Fever?

droplets containing Streptococcus pyogenes

What causes Pneumonia?

bacteria/viruses including streptococcus pneumoniae, staphylococcus aureus and haemophilus influenzae.

What can Pneumonia and its bacteria cause?

latter can cause middle ear infections, meningitis, bronchitis, sinusitis, and conjunctivitis.

What is bacteria is Diphtheria caused by?

Corynebacterium diphtheria

What bacteria can meningitis also be caused by?

Neisseria meningitides.

DTP Vaccine and Bacterial Diseases.

agents causing diphtheria, pertussis, and tetanus generally not a problem being included in this vaccine given to children.

What bacteria causes Tetanus?

Clostridium tetani

What are the viral forms of pneumonia?

influenza virus, adenovirus, and respiratory syncytial virus.

What causes common cold?

number of Rhinoviruses and other viral agents.

what causes influenza, bronchitis, and pneumonia?

number of influenza viruses.

What causes Cytomegalovirus (CMV) and roseola?

herpesvirus types 5, 6, and 7 in saliva.

Measles, Rubella, Mumps MMR Vaccine

viral disease transmitted respiratory/oral fluids with vaccine protecting body from all three.

Infection Control Procedures Regarding Patient - to - Dental Team Transmission

overall measures of hand washing, glove and other PPE use, rubber dams, immunizations. indirect prevented with needle safety/cleanup.

Infection Control Procedures Regarding Dental Team - to - Patient Transmission

hand washing, gloves, immunizations, instrument sterilization, surface disinfection, and masks/face shield.

Infection Control Procedures Regarding Patient - to - Patient Transmission

mainly occurs through indirect contact, sterilization of instruments, disinfection of surfaces, flushing of DUWL, changing of PPE, and use of disposables are important.

Infection Control Procedures Regarding Office - to - Community Transmission

proper handling of contaminated waste and laundry.

Infection Control Procedures Regarding Dental Team - to - Family

immunizations

Infection Control Procedures Regarding Community - to - Patient Transmission

requires good water control procedures

What are the categories of microbes?

bacteria, fungus, viruses, and protozoa.

Bacteria Determination

designated by species within that genus, tiny, single - cell organisms with each having specific characteristic shape and size microscopically, staining pattern, colony growth, metabolic properties, antibodies eliciting immunological responses, and specie - specific genetic potential on DNA/RNA.

What are the different bacterial shapes?

cocci = spherical, bacilli = rod - shaped, and spirilla = spiral.

cocci/bacilli may exist in clusters (staphyl.) or chains (strepto.)

What is the most common staining method if differentiating bacteria and growth?

gram stain, differentiating between gram negative (red) or gram positive (blue/purple) bacteria.

What is unique regarding gram negative bacteria?

the outer membrane containing endotoxin (lip polysaccharide protein - complex) that can be discharged after cell death causing various outward reactions in the host.

Define a Capsule

In some bacteria, containing polysaccharides/water from the cytoplasmic membrane aiding in surface attachment, defense against phagocytosis, and protection against drying.

Define Flagella

threads projecting outwards on some bacteria, aiding in locomotion.

define fimbriae/pili

found on many bacteria, hair like projections aiding in attachment to surfaces and transportation of DNA, making them often more virulent cells.

Define Endospore/Spore Production

found within the cell of some bacteria increasing virulence due to the thick walls and ability to lie dormant being released at later dates, and quite resistant to infection control measures.

What are the components making up Bacterial Cells?

nucleus composed of DNA controlling the cellular activities, equipped with a larger cytoplasm (viscous, containing essential macromolecules, water, oxygen, waste products, and storage granules) surrounding the nucleoid enclosed in the cytoplasmic membrane serving to regulate transportation of nutrients, metabolic functions, waste expulsion, cell wall synthesis, and DNA synthesis during division. Surrounding the cytoplasmic membrane is the rigid cell wall functioning retaining cell shape and protection from mechanical injury.

What are the Different Oxygen Requirement for Bacterial Cells?

vary falling into 4 categories, the obligate aerobes, microaerophiles, facultative anaerobes, and obligate anaerobes

What do bacterial cells with any oxygen requirement possess?

enzymes - superoxide dismutase (SOD) and catalase. SOD breaking down toxic superoxides into molecular energy/hydrogen peroxide and catalase converts hydrogen peroxide into water/molecular oxygen.

Obligate Aerobes

require oxygen to grow/live (about 20% oxygen)

Microaerophiles

grow/live in low levels of oxygen (about 4%).

Facultative Anaerobes

can grow/live with or without oxygen.

Obligate Anaerobes

cannot grow/live in presence of oxygen, does not have SOD/catalase.

Bacterial Growth/Manifestation

bacterial cells divide by binary fission producing two daughter cells, under the right conditions this occurs rapidly.

How is Bacterial growth and manifestation influenced?

influenced by the temperature of the environment, its acidity, available nutrients, oxygen requirements met or not, and presence of water.

What are the temperature ranges for bacterium?

thermophiles (45-70c), mesophiles (22-45c), psychrophiles (1-22c)

What is the optimal temperature range to most bacteria in the human body?

mesophiles (22-45c)

What pH does bacteria grow best in?

neutral pH7 or in slightly acidic/alkaline range of 5.5 - 8.5

Define aciduric

bacteria enduring and growing in lower pH

Define acidogenic

bacteria producing acid during growth contributing to decay

Define catabolism

breakdown of nutrients into utilizable form usually before anabolism providing energy needed.

Define anabolism

synthesis of the broken down new molecules, generating the needed proteins, nucleic acids, lipids, polysaccharides, and vitamins within cell.

How is bacteria cultured?

2 ways; liquid broth or semi - solid agar medium.

Liquid Broth Culture Bacterial Identification technique

sterile techniques, bacteria inoculated into broth cultures observing for turbidity/opaqueness indicating growth

Semi - Solid Agar Medium Bacterial Identification Technique

sterile techniques, bacteria streaked onto agar medium petri dish plates, separating cells into groups called colony - forming units (CFUs).

- further plates can be streaked with individual CFU obtaining pure clones/colonies.

How are the bacterial culture methods useful?

specific bacteria have characteristic growth media (set nutrients/incubated under certain conditions) in which they thrive/proliferate aiding in identification.

Bacteriostatic

agents/states inhibiting bacterial growth but not killing them.

What measures reach bacteriostatic?

freezing, refrigeration, regulating oxygen levels, or use of extreme pH.

define Bactericidal

agent/state that kills bacteria.

What measures reach Bactericidal?

exposure to extremely high temperatures (steam, dry heat, or chemical - vapor sterilizers). chemicals are made killing bacteria on inert objects.

Define Virucidal

agent/state capable of killing viruses.

Define fungicidal

agent/state capable of killing fungus.

How is bacteria treated in body system?

antibiotic use can inhibit or kill bacterial cells.

What 3 features are needed for dental decay?

acidogenic bacteria present in environments of susceptible hosts, and sugars are in the diet.

define plaque

soft, sticky, biofilm of bacteria trenched in intercellular matrix of other molecules particularly glycoproteins from saliva coating the tooth called the pellicle.

The Normal Oral Microbiota

newborns will acquire microorganisms through mother in birth canal but most will not remain, during childhood exposure to environments introduces microorganisms to oral surfaces multiplying becoming part of their oral microbiota. by early teens, normal oral flors established as mixture of 40 types of bacteria (often candida albicans)

What bacteria seen in the oral flora are likely to cause caries?

mutans streptococci, lactobacillus, and actinomyces naeslundii.

How does Streptococci cause dental caries?

acidogenic cells breaking down sucrose sugars binding to cells encouraging plaque formation.

how does Lactobacillus cause dental caries?

acidogenic cells with difficult ways of attachment to tooth surfaces.

How does Actinomyces naeslundii cause dental caries?

if present increase plaque formation and development of root caries.

What is Pulpitis?

inflammation of the pulp when caries spreads to this portion with possibility of spreading further to apex/periapical/adjacent facial tissues causing inflammation and cellulitis.

How is Pulpitis treated?

generally endodontically, with root canal procedures removing dead pulp tissue, killing/pulling out bacteria and adding inert materials to canals. antibiotics also may be given.

Define transient bacterium

normal oral flora entering bloodstream due to oral bleeding can be a problem.

Virus Characteristics

very small consisting of central nucleic acid core (DNA/RNA) and protein coat the capsid. cannot replicate unless existence is in a susceptible host like the body.

Explain a viruses lifecycle

initiated by absorption/attachment to host cell, followed by penetration of the host cell and uncoating the capsid for replication and assembly of new viral particle that is then release upon lyse of cell. continues being replicated in the same way then lying dormant until reactivated at later events causing chronic or slow persistent infections.

How do viruses result in Tumors?

when penetration of host cell and replication is performed, virus in turn transforms host cell instead of lyse.

Can viruses be killed inside the body?

they can be treated on surfaces the same as bacteria, but is not killed inside the body.

What is Rickettsiae

tiny parasitic microorganisms living/multiplying in various hosts, transmitted to humans most times via flea/tick or some cases a rodent.

In Dentistry, what is the biggest concern of Rickettsiae?

those spread by head lice, causing pediculosis.