Micro 2 Lecture 13

Front 1

Factors affecting Infection:

Back 1

-Pathogen Adhesion Mechanism
-Virulence Factors
-True Pathogens vs. Opportunistic Pathogens
-Portal of Entry & Exit
-Microflora
-Size of Inoculum

Front 2

Define Infection:

Back 2

When a pathogenic microbe penetrates the host defenses and multiplies in host tissues, causing disease.

Front 3

Type of pathogen that only causes disease in immuno-compromised individuals.

Back 3

Opportunistic pathogen

Front 4

Type of pathogen that causes disease even in healthy individuals.

Back 4

True or primary pathogen

Front 5

Resident flora =

Back 5

microflora

Front 6

Resident flora includes these micro-organisms:

Back 6

-Bacteria
-Fungi (yeasts)
-Arthropods

Front 7

Most of these areas of the body harbor resident flora:

Back 7

Most areas of the body in contact with the outside environment harbor resident microbes.

Front 8

How do resident bacteria benefit host?

Back 8

Bacterial flora benefit host by preventing overgrowth of harmful microbes.

Front 9

all of the natural normal microbes that we expect to find on or in a healthy human:

Back 9

microflora or resident flora

Front 10

Does the INSIDE of the body harbor microflora?

Back 10

NO, only the parts of the body that are exposed to the outside environment, like the G.I. tract of the skin.

Front 11

The part of the body that harbors the most floral organisms is:

Back 11

the Large Intestine

Front 12

Does the stomach harbor flora?

Back 12

yes, which is shocking given the acidity.

Front 13

What are the three main benefits of the microflora?

Back 13

1) Assists in digestion: Helps breakdown a lot of food products that we cannot breakdown on our own.
2) Produces vitamins: vit. K by E. coli,
3) Prevents infection: Floral organisms out compete pathogens & some aggressively attack them, (E. coli attacks salmonella)

Front 14

How much flora is in the typical human body?

Back 14

There are more floral cells than human cells.

Front 15

How long does it take for newborns to be colonized with flora?

Back 15

within 8-12 hours after birth

Front 16

What is the newborns first contact with flora?
-Subsequent contact?

Back 16

through the birth canal, then through feeding and contact with the outside environment.

Front 17

What are the ways that pathogens enter the body?

Back 17

-Inhalation
-Ingestion
-A break in the skin
-STD, sexual contact

Front 18

Describe the portal specificity of pathogens:
Examples?

Back 18

Some pathogens can only set up infection through 1 portal; others can set up an infection through multiple portals.
-For example: Influenza can only infect through the nasal mucosa, so you have to inhale it through the nasal mucosa.
-Dermatophyte: only infects through the skin. If you inhaled a dermatophyte spore, nothing would happen.
-Mycobacterium tuberculosis: can set up infection whether it is inhaled OR ingested.

Front 19

Regarding the size of the inoculum: Infection will proceed only if:

Back 19

A minimum number of microbes are inoculated into the host.

Front 20

Define the Infectious Dose:

Back 20

the quantity of microbes needed to cause disease in the host.

Front 21

Does the Infectious Dose vary widely between organisms?
Examples?

Back 21

yes;
For example: the Infectious Dose for Giardia is 10. If you ingest 9 cysts, you don't get sick. If you ingest 10 cysts you do get sick.

Front 22

What is the Infectious Dose for Neisseria gonorrhoeae?

Back 22

you have to be exposed to 1,000 gonorrhea cells to get gonorrhea.

Front 23

What is the Infectious Dose for Salmonella typhi?

Back 23

You have to ingest 10,000 Salmonella typhi cells.

Front 24

What is the Infectious Dose for Cholera?
How do you get Cholera?

Back 24

You have to ingest 1 million Vibrio cholerae cells.
-By ingesting food or water contaminated with human feces.

Front 25

What is the Infectious Dose for the organism that causes q fever?

Back 25

1 cell

Front 26

Generally the lower the Infectious Dose of an organism, the __________
it is.

Back 26

Generally the lower the Infectious Dose of an organism, the MORE DANGEROUS
it is.

Front 27

What ways can bacteria attach to host tissues?

Back 27

-fimbrae
-glycocalyx: capsule or slime layer
-hooks on flagella

Front 28

Does having fimbrae make a bacteria more pathogenic?

Back 28

yes

Front 29

Do some Euks attach with hooks?

Back 29

yes

Front 30

The ability of a microbe to invade a host and produce substances to damage the host:

Back 30

Virulence

Front 31

The substances that are produced by the microbe that damage the host are called:

Back 31

Virulence Factors

Front 32

What are the Virulence Factors:

Back 32

-Exoenzymes
-Antiphagocytic Factors
-Toxigenicity: endotoxins & exotoxins

Front 33

Are Virulence Factors made to harm us?

Back 33

Not necessarily. They are things made by the microbe in order to help its survival, but cause damage to us.

Front 34

An enzyme made and secreted by a microbe that damages host tissues.

Back 34

Exoenzymes

Front 35

Two important examples of exoenzymes are:

Back 35

Keratinase & Hyaluronidase

Front 36

Keratinase is an exoenzyme made by:

Back 36

the Dermatophytes

Front 37

One of the few pathogens that can infect through the keratin:

Back 37

Dermatophytes

Front 38

What does keratinase do?

Back 38

it breaks down the keratin in our skin, hair, & nails.

Front 39

Hyaluronidase is made by:

Back 39

both Staphylococcus & Streptococcus

Front 40

What does Hyaluronidase do?

Back 40

it breaks down the basement membrane

Front 41

Hyaluronidase aka=

Back 41

Spreading Factor

Front 42

One of the things that the glycocalyx can do to increase virulence is to inhibit __________.

Back 42

One of the things that the glycocalyx can do to increase virulence is to inhibit PHAGOCYTOSIS BY WBCs.

Front 43

What feature on the bacteria is an Antiphagocytic factor?

Back 43

the Glycocalyx: either capsule or slime layer.

Front 44

Are bacteria with a glycocalyx destroyed by the WBC?

Back 44

no

Front 45

What are the 3 types of Antiphagocytic Factors?

Back 45

-the Glycocalyx
-something that kills WBCs: like the protein leukocidin that kills WBCs
-Surviving inside the WBC

Front 46

What bacteria produce Antiphagocytic proteins that kill WBCs?

Back 46

Staphylococcus & Streptococcus produce the protein leukocidin that kills WBCs.

Front 47

Example of a bacteria that can live its entire lifecycle inside the WBC if phagocized?

Back 47

Chlamydia

Front 48

A specific chemical product made by one organism that is poisonous to other organisms.

Back 48

a Toxin

Front 49

Toxins in the blood or tissues:

Back 49

Toxemia

Front 50

The ingestion of toxins:

Back 50

Intoxication

Front 51

What are the two types of bacterial toxins?

Back 51

-Exotoxins &
-Endotoxins

Front 52

Protein toxins that are made and secreted by a bacteria:

Back 52

Exotoxins

Front 53

Which bacteria make exotoxins, Gram + or Gram -?

Back 53

Both

Front 54

Are Exotoxins heat resistant?

Back 54

Yes, since they are proteins, they have to be cooked for a long time to be destroyed.

Front 55

Describe Exotoxins:
-Composition:
-Made by:
-Heat sensitivity:
-How acquired:
-Potency:
-Targets:
-Disease:
-Prognosis:

Back 55

-Composition: Proteins secreted by LIVE bacterial cells into the environment.
-Made by: Gram + AND Gram -
-Heat sensitivity: Heat resistant
-How acquired: By ingesting the toxin itself, (don't need to ingest the actual cell)
-Potency: Very potent in low doses
-Targets: Specific targets (affect: just the G.I. tract, muscular system, heart tissue)
-Disease: Since Exotoxins attack specific organs: NO FEVER
-Prognosis: Quick onset of sickness but quick recovery.

Front 56

Describe Endotoxins:
-Composition:
-Made by:
-Heat sensitivity:
-How acquired:
-Potency:
-Targets:
-Disease:
-Prognosis:

Back 56

-Composition: LPS (Lipopolysaccharides) released when cell dies.
-Made by: Only Gram -
-Heat sensitivity: Quite sensitive, cooking destroys it
-How acquired: Have to ingest the entire cell.
-Potency: not as potent as Exotoxin
-Targets: has systemic effects: inflammation, hemorrhaging, GI problems, fever.
-Disease: Difficult to treat as patient can go into Endotoxic shock, they can get worse before they get better.
-Prognosis: Takes longer to get sick, but also longer to recover than Exotoxins.

Front 57

Food poisoning is most commonly caused by:

Back 57

Staphylococcus aureus

Front 58

The classic example of an Exotoxin event is:

Back 58

Food poisoning by Staphylococcus aureus.

Front 59

What is the Hallmark symptom of an Endotoxin event?

Back 59

Fever

Front 60

Does an Exotoxin event produce fever?

Back 60

NO

Front 61

What are the stages of infection?

Back 61

1) Incubation period
2) Prodromal stage
3) Period of Invasion
4) Convalescent period

Front 62

Define the Incubation Period:

Back 62

The time from the initial contact with the pathogen until the first symptoms.

Front 63

Define the Prodromal stage:

Back 63

Stage that lasts a short time with vague symptoms.

Front 64

Define the Period of Invasion:

Back 64

Stage when the microbe is multiplying at high levels in the host tissues and is exhibiting its greatest virulence and worst symptoms.

Front 65

Stages of Clinical Infections:
What are the two possible outcomes for the patient after the Period of Invasion?

Back 65

they die or enter the Convalescents Period

Front 66

Define the Convalescents Period:

Back 66

Stage where the health of the patient is improving & the symptoms are declining.

Front 67

What are the patterns of infection?

Back 67

Focal, Mixed, Localized & Systemic infections.

Front 68

Define the Localized infection:
Example:

Back 68

A type of infection that remains confined to a specific tissue.
Example: a boil; remains confined to skin.

Front 69

Define Systemic infection:
How does it usually spread?
Examples?

Back 69

A type of infection that spreads to several sites; usually spreads through the blood or lymph fluid.
Example = rabies, syphilis

Front 70

Define Focal infection:
Example?

Back 70

A type of infection where the agent breaks loose from a LOCAL infection and is then carried to a specific other site.
Example: tuberculosis starts as a lung infection but pieces of it can break off and travel to the heart causing Scarlett Fever.

Front 71

Define Mixed infection:
Example?

Back 71

A type of infection where several agents infect the same SITE at the same TIME.
Example: a bite wound; mouths can harbor numerous different microbes.

Front 72

Other terms involved with Patterns of Infection:

Back 72

-Chronic infection
-Acute infection
-Asymptomatic infection
-Primary infection
-Secondary infection

Front 73

Describe the Primary infection & Secondary infection:

Back 73

Sometimes you can get an infection that causes a another infection. For example: Chicken pox (primary infection) causes you to scratch so much that you break the skin leading to a Staph infection (secondary infection).

Front 74

How are the Primary and Secondary infections distinguished from the Mixed infection?

Back 74

Mixed infections occur at the same time. In the Primary / Secondary infection relationship, one occurs BEFORE the other.

Front 75

Define Acute infection:

Back 75

Infection that comes on rapidly with severe but short-term effects.

Front 76

Define Chronic infection:

Back 76

An infection that progresses and persists over a long time period.

Front 77

Define Asymptomatic infection:

Back 77

An infection with no noticeable signs and symptoms.
-Most dangerous from a public health perspective.

Front 78

Which infection would someone be LESS likely to seek help and MORE likely to pass it on to others?

Back 78

Asymptomatic infection

Front 79

Define Epidemiology:

Back 79

The study of the frequency and distribution of disease.

Front 80

The history of Epidemiology can be traced back to a man named________ during an outbreak of _________.

Back 80

John Snow; Cholera

Front 81

What exactly did John Snow do?

Back 81

He surveyed a bunch of London residents and after analyzing his data, discovered that everyone who got cholera, got it from the same well water.

Front 82

Epidemiology relies on:

Back 82

Surveillance

Front 83

Define Surveillance:

Back 83

The collecting, analyzing, & reporting of data on rates of mortality, morbidity, occurrence, and transmission of infections.

Front 84

Who takes care of all of the Epidemiological info in the U.S.?
Worldwide?

Back 84

the CDC
worldwide= WHO

Front 85

Epidemiologists track:

Back 85

-Prevalence of a disease
-Incidence of a disease
-Morbidity rates
-Mortality rates

Front 86

Prevalence of a disease =

Back 86

total # of cases ÷ total # of people

Front 87

Incidence of a disease =

Back 87

# of new cases ÷ susceptible population.

Front 88

Which Epidemiological measure is used to track whether a disease is becoming more common or less common in a defined time period?

Back 88

Incidence of a disease

Front 89

Define Morbidity rate:

Back 89

The number of people afflicted with a disease.

Front 90

Define Mortality rate:

Back 90

The number of people who have died from a disease.

Front 91

What are the patterns of infectious disease occurrence?

Back 91

-Endemic
-Epidemic
-Sporadic
-Pandemic

Front 92

Describe Endemic diseases:

Back 92

Disease is at a relatively steady frequency over a long time period.
(lyme disease)

Front 93

Describe Sporadic diseases:

Back 93

Occasional cases of disease that are seen in random locations and at irregular intervals.

Front 94

Describe an Epidemic:

Back 94

Prevalence of the disease is increasing beyond expected levels; cases of a disease are increasing.

Front 95

What diseases are at epidemic rates in California?

Back 95

Whooping cough and chlamydia

Front 96

Describe a Pandemic:

Back 96

A Pandemic is an Epidemic occurring on multiple continents. (HIV)

Front 97

Determining how a disease is transmitted is accomplished through:

Back 97

Investigation of a patient's background:
-Locations frequented
-Habits
-Food
-Sexual partners
-Possible contacts

Front 98

Define Transmission:

Back 98

The exchange of a pathogen from infected individual to uninfected hosts.

Front 99

What are the two methods of Transmission?

Back 99

-Direct (kissing, sex, large droplets, biological vectors)
-Indirect (airborne droplet nuclei, fomites, food)

Front 100

Direct Transmission is:

Back 100

The direct contact between the portal of EXIT and the portal of ENTRY. (kissing, sex etc.)

Front 101

Indirect Transmission is:

Back 101

When there is NOT DIRECT contact between the portals of exit and entry of hosts.

Front 102

Are large droplets from sneezing or coughing considered Direct or Indirect Transmission?

Back 102

DIRECT!

Front 103

A live animal that transmits the infectious agent between hosts.

Back 103

Biological Vector

Front 104

Is Transmission through Biological vectors considered Direct or Indirect?
What about mechanical vectors?

Back 104

Biological vectors=DIRECT; Mechanical vectors are INDIRECT.

Front 105

An inanimate object that Transmits an infectious agent between hosts.

Back 105

Fomite

Front 106

Tiny droplets that are created from speaking that can hang in the air for hours:

Back 106

Droplet nuclei

Front 107

Is food a Fomite?

Back 107

not in the example; it is a separate vehicle for Indirect Transmission.

Front 108

The primary habitat in the natural world from which a pathogen originates.

Back 108

the Reservoir of Infection

Front 109

Describe the two types of Reservoirs of Infection:

Back 109

-Living: Living reservoirs may or may not have symptoms.
-Nonliving: Nonliving reservoirs-soil, water.

Front 110

Living Reservoirs of Infection could be from a person at any stage of the ________ cycle:

Back 110

Infection cycle:
-Incubation
-Convalescent
-Chronic
-Asymptomatic

Front 111

Someone that had the infection, recovered from the it and continues to shed the microbe.

Classic example?

Back 111

Chronic Reservoir;

Classic example: Typhoid Mary. Mary Malone who was a short order cook and kept spreading the disease.

Front 112

An infection indigenous to animals but transmissible to humans.
Does it hurt the animal as well?

Back 112

Zoonosis

Does it hurt the animal as well? Sometimes yes, sometimes no. Rabies hurts animals and humans. Salmonella is a normal part of some animals GI tract but it will hurt us.

Front 113

What are the two types of vectors?

Back 113

-Biological Vectors: Participates in the pathogen's lifecycle.
-Mechanical Vectors: Transport the pathogen but don't participate in it's lifecycle.

Front 114

A live animal that Transmits an infectious agent between hosts.

Back 114

a Vector

Front 115

Would a mechanical vector be considered Direct Transmission or Indirect Transmission?

Back 115

Indirect Transmission

Front 116

Diseases that are acquired during a hospital stay.

Back 116

Nosocomial Infections

Front 117

The Nosocomial Infection rates in the U.S. range from:
The U.S. avg. is:

Back 117

0.1% - 20% of admitted patients
The U.S. avg. is: 5%

Front 118

Nosocomial Infections cause ____ deaths each year.

Back 118

90,000 deaths.

Front 119

Why is the hospital such a breeding ground for infections?

Back 119

-Immunocompromised hosts
-large population of pathogens
-its likely that many of the pathogens are antibiotic resistant.

Front 120

Most Nosocomial Infections are:

Back 120

Urinary tract infections (40%)

Front 121

Joseph Lister proved that microbes caused disease, Robert Koch wanted to find out:

Back 121

which microbe causes which disease.

Front 122

Robert Koch est. Koch's Postulates as a way to show:

Back 122

that a specific microorganism is responsible for a particular disease.

Front 123

What did Robert Koch develop?

Back 123

pure culture methods

Front 124

Robert Koch identified the cause of which diseases?

Back 124

Anthrax, TB, & Cholera

Front 125

An example of a pure culture technique developed by Robert Koch:

Back 125

streak-plating

Front 126

Koch's Postulates are used for:

Back 126

determining the causative agent for a disease.

Front 127

Koch's Postulates:

Back 127

1) Correlate every case of disease with the presence of a certain microbe.
2) Isolate that microbe from an infected subject, cultivate it in pure culture in the lab & identify it.
3) Inoculate a healthy susceptible subject with the laboratory isolate and observe the same resultant disease.
4) Reisolate the agent from this subject in pure culture and prove it's the same microbe that you inoculated into the animal.

Front 128

Koch's Postulates are the "gold standard" but:
For example:

Back 128

they don't work for all situations and all disease causing organisms.
For example:
-don't work for viral infections. (can't grow a virus in pure culture)
-don't work for diseases that have multiple causative agents. (pneumonia is can be caused by bacteria, viruses, fungi) so step #1 can't be proven.

Front 129

What are some examples of when Koch's Postulates won't work?

Back 129

-When a disease has multiple causative agents (pneumonia) violates step 1.
-Viruses (because they can't be grown in a pure culture)
-Microbes that cause multiple diseases: (Streptococcus pyogenes) can cause strep throat in the throat, scarlet fever in the heart, necrotizing fasciitis in the skin. violates step 1.

Front 130

What are other disciplines are using Koch's Postulates?

Back 130

environmental microbiology.

Front 131

What is the goal in applying the information from epidemiological studies?

Back 131

Determine recommendations for: -individuals
-public health policy

Front 132

What are some examples of recommendations for individuals:

Back 132

wash hands, don't touch face during flu season, get vaccines, don't eat this food at this time.

Front 133

What are some examples of recommendations for public health policy:

Back 133

-stockpile specific medication
-encourage companies to produce vaccines or tests
-institute no fly zone

Front 134

What is the goal of epidemiology?

Back 134

to predict the future of the disease

Front 135

What are the advantages to predicting the future of a disease?

Back 135

-this allows for more efficient use of resources
-allows for suggestions on how to slow/stop the spread of disease