a disease entity is characterized by at least two of these criteria:

1.) a recognized etiologic agent

2.) an identifiable group of signs and symptoms

3.) consistant anatomical alterations.

the microbe must:

- be present in every case of the disease.

- be isolated from the diseased host and grown in pure culture.

- be reproduced when a pure culture is introduced into a non-diseased suseptible host

- be recoverable from an experimentally infected host.

Scientific Method

make an observation

develop a hypothesis

test the hypothesis (must have controls!)

data collected, results obtained

results verified, conclusion drawn.

Bacteria

10x

the adult human has this many times MORE microbial cells as mammalian cells.

Indigenous Microbiota

(also referred to as resident, commensal, or normal flora)

Parasite

- a life form that lives on or in another life form (host)

- another orginism that resides on or within another organism in order to find an environment and nutrients required for growth and reproduction.

- may or may no harm the host

an orginism which lives on dead organic matter

Pathogenicity

Virulence

Disease

a compromised host

Normal Flora

microorganisms normally residing on body surfaces or in varoius cavities of the body without invasion or harm to the host. Also known as indigenous, resident, or commensal flora.

Bacteria - majority of species

Fungi

Protozoa

Viruses

a mite: Demodex folliculorum

a positive interaction which produces substances utilized by other species

ex: lactic acid produced by streptococci utilized by Veillonella spp.

a bacterial interaction that inhibits other species

ex: bacteriocins, organic acids, hydrogen peroxide

it prevents colonization by potential pathogens

ex: the release of substances that have metabolic value for the host - vitamins

it makes opportunistic infections more likely by spreading to sterile areas, overgrowth with changes in local environmental conditions and immunosupression.

Direct contact,

indirect contact (aerosols, droplets, formites - contaminated instruments)

fecal-oral route,

Injection, wound or bite

transmission

retention/adhearence

growth/replication

adaptation

evolution

organisms must go through one of these inorder to cause an infection

multiplication

Virulence Factors

intrinsic properties of pathogenic microbes which allow them to overcome the host defencesand establish an infection

- enhance the ability of pathogenic microorganisms to cause disease

- replication that allows establishment

- may replicate at portal of entry and remian localized or may invade underlying tissues.

-produce toxic proteins (exotoxins)

- endotoxin of gram negative cell walls

- cell wall molecules and structures enhance their atachment to sufaces

- have capsules that allow them to avoid phagocytosis

-survive in phagocytic cells

- grow intracellularly

- have ability to invade and spread

-requires a receptor and an adhesion

usually protein

often associated with pili

may be associated with a capsule

the ability of microorganisms to invade human tissues

ex: enzymes and invazins

ex: hyalurondase - breaks down hyaluronic acid and allow bacteria to invade the cell

- bacterial surface coating

- also known as glycocalyx or slime layer

- usually a simple polysaccharide

- convey antiphagocytic properties to the cell

polymer of D-glutamic acid

has a protein capsule instead of a polysaccharide

dental plaque = bacteria + glycocalyx (capsule)

biofilms in dental waterlines

- LPS - cell wall, responsible for the toxicity

- bacteria found withinin gram negatives only

- less potent but stable to heating

- gram positives or gram negatives

- destroyed by heat

- highly toxic

- released extracellularly

-exotoxin that kills cells

- blocks protein synthesis and interferes with cellular functions

- disrupts the cell membranes causing the cell to lyse

-exotoxin that causes intestinal inflammation

- causes a water/ion loss = diarrhea

Neurotoxins

-exotoxin

- ex = colstridium botulinum

- most potent toxin known, supresses the release of acetylcholine

-exotoxin that have the ability to stimulate T cells to release cytokines

ex: Toxic Shock Syndrome

1.) virulence of the microorganism

2.) Dose

3.) Host resistance

Determinants of Infectious Diseases

Increase Resistance

Decrease Dose

the best descriptive term for the resident flora

damage red blood cells

the occourence of Lyme disease mainly in areas where certain species of ticks live would define it as this

exogenous

how microbes enter the body.

generally those that harbor microflora

obligate intracellular parasites

cause Rocky Moutain spotted fever, genitourinary, and ocular infections

-free-living

-lack a cell wall

- sterols in membrane

- cause "walking pneumonia

-eukaryotic cells

- cell walls contain chitin

-unicellular = yeasts

- others grow as filamentous hyphae and form masses known as mycelia

-unicellular, eukaryotic organisms

-usually lack a cell wall

-may be commensal organisms

- some are pathogenic for man

-non-living organisms

-acellular- not prokaryotic or eukaryotic

-contain DNA or RNA as a genome

-have a protein coat (capsid) surrounding nuclic acid

-

anginosus group of oral streptococci found in the oral cavity, URT, and vagina.

- it is often found in purulent (pus) infections.

-Salivarious group of oral streptococci found in the oral cavity, esopogus, tongue and saliva.

- first microorganism to colonize in humans

actinomyces and lactobacillus are both:

gram positive/negative?

rod/cone?

-gram-positive rod that may have a role in carie development because it produces lactic acid, but its still uncertain, but they are associated with deep dentinal caries

-gram-negative cocci that is anaerobic, takes lactic acid in the body and converts it into acedic acid and propionic acid

- 5-10% culitivable organisms on tongue and in saliva

-about 25% of the normal flora in a healty mouth

-proportions may double with gingivitis and PPD

-most infections involoving them are mixed infections

-gram negative rods that are among the major cause of PPD

-abscesses, pulmonary and ear infections, would infections, chronic sinusitis, peritonitis 

- anaerobic

- commonly associated with PPD

- present in half of adults with "clean healthy mouths"

- its numbers increase with PPD

- virus that is a persistent, latent infection

- once you're infected, your always infected 

-asymptomatic

-mostly asymptomatic but can cause infection

- there are a number of them that cause persistant infections

-predominant once the teeth erupt and stays as long as a person has teeth

-attaches to the teeth

-most abundant of the streptococc

- major component of PPD

-frequently found in children under 3 years with a primary dentition

- most strongly associated with pubertal periodontitis

-but there is also a high incidenc ein children under 3 years

-often are associated with pilli

- have a specific interaction with a receptor

- usually are protein

- are protein

- released extracellularly 

- are highly toxic

The bacterial structure which is a major component of biofilms such as dental plaque is the:

- capsule

- cell wall

- flagella

- lipopolysaccharide

Which of the following represents potential transmission via INDIRECT CONTACT?

- contact with a patient's saliva duw to a hole in a glove

- dental aerosols

- improperly sterilized dental instruments

- both B and C

- all of the above

__________________ bacteria are associated with the development of dental caries whereas _________ bacteria are associated with the development of periodontal disease and are more often ____________

-g(+)/g(-)/aerobic

-g(+)/g(-)/anaerobic

-g(-)/g(+)/aerobic

-g(-)/g(+)/anaerobic

THe microorganism most responsible fot the initiation of dental caries in the crowns of teeth is:

- actinobacillus actinomycetemcomitans

-actinomyces viscosus

- lactobacilus casei

- streptococcus mutans

- streptococcus sanguinus

Oral streptococci produce lactic acid that can be utilized by Veillonella spp. This interaction is referred to as:

-antagonism

- commensalism

- synergism

- symbiosis

Enterotoxins are a type of _______ and often result in ___________

- andotoxin /hospitalization

- neurotoxin /death

- exotoxin/diarrhea

- endotoxin/diarrhea

- exotoxin/paralysis

The most common outcome of a microbial infection is:

- asymptomatic infection

- mild disease

- classic disease

- death

Lipopolysaccharide is also referred to as:

-endotoxin

-enterotoxin

-exotoxin

-none of the above

The microorganisms associated with dental caries and periodontal disease are best described as:

- commensals

- frank pathogens

- opportunists

- principal pathogens

- symbiotic

The first step in colonization of a host by a microorganism is:

- attachment

- invasion

- multiplication

- phagocytosis

- toxin production

Glycocalyx and slime layer are terms which may be used to designate the bacterial:

-cell wall

-capsule

-envelope

-none of the above

The patient with a healthy mouth would have which of the following in greatest numbers?

- gram positive cocci

- gram positive rods

- gram negative cocci

- gram negative rods

The most abundant genus of bacteria found in a healthy mouth is:

-actinobacillus

- lactobacillus

- prevotella

- staphylococcus

- streptococcus

Streptococci produce bacteriocins which inhibit other bacteria. This interaction is referred to as:

- antagonism

- commensalism

- symbiosis

- synergism

Which of the following is NOT necessary for an infectious microorganism to be sucessful?

- attachment

- cause damage

- evasion of immune defenses

- replication

- shedding

Which of the following characterizes bacterial adhesins?

- often associated with pili

- specific interaction with receptor

- usually protein

- Both A and B only

- A, B, and C

Which of the following bacterial genera is most common on human skin and in the nasopharynx?

-Haemophilus

- Neisseria

- Propionibacterium

- Stachlococcus

- Streptococcus

The first microorganism to be consistently found in the oral cavity of a newborn is:

- Lactobacillus acidophilus

- Streptococcus mutans

- Streptococcus oralis

- Streptococcus sanguinus

- Streptococcus salivarius

At what age do individuals first harbor those bacteria which may later cause periodontal disease?

- neonatal period

- early childhood

- 8-13 years

- teenage years

- adulthood

Which of the following organisms are primarily associated with periodontal disease in man?

- Actinobacillus actinomycetemcomitans and Streptococcus Sobrinus

- A. actinomycetemcomitans and Actinomyces viscosus

- A actinomycetemocomitans and Porphyromonas gingivalis

The spread of an epidemic across continents initially results in a/an:

- endemic disease

- pandemic diseae

- Either A or B

- neither A nor B

Normal flora may cause opportunistic infections if:

- they spread (or are spread) into normally sterile areas

- the patient becomes immunosupressed

- the local environment changes (patient taking antibiotics)

- A and C only

- A, B, and C

A fomite is:

- an arthopod which acts as a vector of disease

- a vertebrae animal which can transmit microorganisms to humans

- a nonliving object which can transfer disease causing microorganisms

A primary distinction between prokaryotic and eukaryotic cells is the absence of _____________ in the former (prokaryotic cells)

- a cell wall

- DNA

- internal membranes

- ribosomes

the flora of the nasopharynx are primarily:

- aerobic

- anaerobic

A cytolytic toxin:

- disrupts cell membranes

- causes lysis of the cell

- both A and B

- Neither A nor b

The majority of species making up the normal flora of man are:

- atrhropods

- bacteria

- fungi

- protozoa

- viruses

An organism that lives on dead organic matter is a:

- commensal

- opportunist

- parasite

- saprophyte

- symbiotic organism

The yeast Candida:

- is part of the normal flora

- may cause opportunistic infections

- both A and B

- Neither A nor B

-predominant mo. once the teeth erupt.

-says in the oral cavity as long as a person has teeth

(which would make it the most predominant mo in an adult mouth)