Chapter 13 Collaborative

Question 1

What does normal resident microbiota mean?

Answer 1

Microbes that engage in mutual or commensal associations with humans

Question 2

What is an infection?

Answer 2

A condition in which pathogenic microbes penetrate host defenses, enter tissues, and multiply

Question 3

What is a pathogen?

Answer 3

A microbe acting as an infectious agent

Question 4

What is an infectious disease?

Answer 4

An infection that causes damage or disruption to tissues and organs

Question 5

What are transients?

Answer 5

Microbes that occupy the body for short periods. Influenced by hygiene, they don’t grow but just cling to the surface

Question 6

What are residents?

Answer 6

Microbes that become established, stable, predictable, less influenced by hygiene. Primarily bacteria and yeasts

Question 7

What is microbial antagonism?

Answer 7

When microbiota benefits the host by preventing overgrowth of harmful microbes

Question 8

What are endogenous infections?

Answer 8

They occur when normal flora is introduced to a site that was previously sterile

Question 9

What sites harbor normal resident microbes?

Answer 9

Skin and continguous mucous membranes, upper respiratory tract, gastrointestinal tract, outer opening of urethra, external genitalia, vagina, external ear and canal, external eye

Question 10

What are some sterile (microbe-free) anatomical sites and fluids?

Answer 10

Blood, urine in kidneys, ureters, bladder, CSF, saliva prior to entering oral cavity, semen prior to entering urethra

Question 11

Where are the most diverse and unique flora of the body located?

Answer 11

In the mouth

Question 12

What kind of bacteria grow best in the intestines?

Answer 12

Anaerobic bacteria, such as Bacteroides, Bifidobacterium, Fusobacterium, Clostridium

Question 13

What are probiotics?

Answer 13

Supplements to introduce known microbes back into the body

Question 14

How do resident microbiota work?

Answer 14

They’re generally stable mitrobiota that usually benefit the host by preventing overgrowth of harmful microbes - microbial antagonism

Question 15

How is resident flora first introduced to a person?

Answer 15

Breaking of the fetal membrane just before birth, and subsequent handling and feeding of the newborn

Question 16

Most common residents of the mouth?

Answer 16

Aerobic Streptococcus species. Such as S. sanguis, S. salivarius, and S. mitis

Question 17

How many microbes are found in feces?

Answer 17

More than/equal to 30% of fecal volume

Question 18

How can microbes of the large intestine benefit the host?

Answer 18

Fermentation of waste materials in feces generates vitamins and acids, and bacterial digestive enzymes can convert disaccharides to monosaccharides or promote steroid metabolism

Question 19

What flora are in the nasal entrance to the anterior nasopharynx?

Answer 19

S. aureus

Question 20

What flora are in the mucous membranes of the nasopharynx?

Answer 20

Neisseria

Question 21

What flora are found in the tonsils and lower pharynx?

Answer 21

Haemophilus

Question 22

What sites harbor microflora in the genitals of females and males?

Answer 22

Females - vagina and outer opening of urethra
Males - anterior urethra

Question 23

How are internal reproductive organs kept sterile?

Answer 23

Physical barriers, such as a cervical plug

Question 24

How are the kidney, ureter, bladder, and upper urethra kept sterile?

Answer 24

By urine flow and bladder emptying

Question 25

How do normal flora assist the body?

Answer 25

They create an environment that may prevent infections and enhance host defenses

Question 26

What factors can weaken host defences and increase susceptibility to infection?

Answer 26

Old age and extreme youth, genetic and acquired defects in immunity, surgery and organ transplants, organic disease, chemotherapy/immunosuppressive drugs, physical and mental stress, other infections

Question 27

What are the 2 types of pathogens?

Answer 27

True pathogens and opportunistic pathogens

Question 28

What are true pathogens?

Answer 28

Capable of causing disease in healthy persons with normal immune defenses. Influenza virus, plague bacillus, malarial protozoan

Question 29

What are opportunistic pathogens?

Answer 29

Cause disease when the host's defenses are compromised or when they grow in a part of the body that is not natural to them. Pseudomonas sp. and Candida albicans

Question 30

What is virulence factor?

Answer 30

A characteristic or structure that contributes to the ability of a microbe to cause disease; anything that allows organism to cause disease. Ex: slime layer/capsule, fimbriae in E. coli

Question 31

What are exogenous agents?

Answer 31

Flora originating from a source outside of the body

Question 32

What are endogenous agents?

Answer 32

Flora that already exist in or on the body. Normal flora

Question 33

What is STORCH?

Answer 33

Pathogens that can infect during pregnancy and become dangerous

Question 34

What is an infectious dose?

Answer 34

The minimum number of microbes required for infection to proceed. Inversely related to virulence.

Question 35

How are infectious dose and virulence factor related?

Answer 35

They are inversely related. A microbe with a high infectious dose will have a low virulence factor, meaning it cannot easily cause disease and must have a high number of organisms to do so. Likewise, a microbe with a low infectious dose has a high virulence factor since it can easily cause infection.

Question 36

What is the difference between infection and infectious disease?

Answer 36

Infection is pathogenic microbes penetrating a host's defenses, an infectious disease is an infection that causes damage or disruption

Question 37

What are antiphagocytic factors?

Answer 37

Factors used to avoid phagocytosis (to survive host defenses)

Question 38

What are leukocidins?

Answer 38

Factors toxic to white blood cells, to help survive host defenses

Question 39

What is the slime layer or capsule?

Answer 39

A factor that makes phagocytosis difficult. To help survive host defenses

Question 40

What is a toxin?

Answer 40

A specific chemical product of microbes, plants, and some animals that has poisonous effects on other organs

Question 41

What are toxinoses?

Answer 41

Adverse effects of toxins

Question 42

What is toxemia?

Answer 42

When a toxin is spread by the blood from the site of infection (like tetanus)

Question 43

What is intoxication?

Answer 43

Caused by ingestion of toxins. Like botulism

Question 44

What are the types of bacterial toxins?

Answer 44

Endotoxin and exotoxin

Question 45

What is an endotoxin?

Answer 45

A toxin that is not secreted, but released after the host cell is damaged or killed

Question 46

What is an exotoxin?

Answer 46

A toxin that is secreted by a LIVING bacterial cell into the infected tissue

Question 47

What are the 4 stages of clinical infections?

Answer 47

1. Incubation period 2. Prodromal stage 3. Period of invasion 4. Convalescent period

Question 48

What happens during the incubation period of a clinical infection?

Answer 48

First stage. Time from first contact w/ infectious agent to the appearance of the first symptoms. Microbe is multiplying but no symptoms

Question 49

What happens during the prodromal stage of a clinical infection?

Answer 49

Second stage. Vague feelings of discomfort, nonspecific complaints

Question 50

What happens during the period of invasion in a clinical infection?

Answer 50

Third stage. Microbe multiplies at high levels, become well-established, more specific signs and symptoms

Question 51

What happens during the convalescent period of a clinical infection?

Answer 51

Fourth and final stage. As person begins to respond to the infection, symptoms decline

Question 52

During which stage of a clinical infection can the disease be transmitted?

Answer 52

ANY stage. Also, the number of microbes is directly related to the intensity of the symptoms

Question 53

What is a sign?

Answer 53

Objective evidence of disease noted by an observer

Question 54

What is a symptom?

Answer 54

Subjective evidence of disease sensed by the patient