Lecture 13

Question 1

Resident microbiota

Answer 1

Includes bacteria, fungi (yeasts), and Protozoa that are on most areas of the body that are in contact with the outside environment like the skin, upper respiratory tract, GI tract, urogenital tract

Question 2

Benefit of resident microbiota

Answer 2

Prevent overgrowth of pathogenic microbes

Question 3

Resident microbiota examples

Answer 3

Lactobacillus in the vagina keep pH low by fermenting glycogen preventing the overgrown of candida, E. coli in the large intestines secrete bacteriocins that prevent the overgrowth of bacteria like salmonella and shigella

Question 4

Resident microbiota examples

Answer 4

Lactobacillus in the vagina keep pH low by fermenting glycogen preventing the overgrown of candida, E. coli in the large intestines secrete bacteriocins that prevent the overgrowth of bacteria like salmonella and shigella

Question 5

Resident microbiota found

Answer 5

Skin, respiratory tract, gastrointestinal tract, external genitalia, vagina, external ear and canal, eye lids and lashes

Question 6

Sterile sites and fluids

Answer 6

Organs including bones, brain, bladder, blood, urine, cerebrospinal fluid

Question 7

Portal of entry

Answer 7

Characteristic routes that infectious microbes enter the body through, every microbe has a specific one

Question 8

Exogenous

Answer 8

Infectious agent originates from source outside the body

Question 9

Endogenous

Answer 9

Infectious agent already exists on or in the body

Question 10

What have most pathogens adapted to

Answer 10

A specific portal of entry

Question 11

Some pathogens

Answer 11

Can enter by more than one portal of entry to cause different infections

Question 12

Infectious dose

Answer 12

The minimum number of microbes to be inoculated into the host for infection to proceed, varies for each organism

Question 13

Ghonnorea

Answer 13

1000 Neisseria ghonnorea cells, through sexual contact

Question 14

Measles

Answer 14

1 measles virus, through respiratory

Question 15

Typhoid fever

Answer 15

10,000 salmonella typhi, through ingestion of fecal contaminated food or water

Question 16

Cholera

Answer 16

1 million vibrio cholera, through ingestion of fecal contaminated water

Question 17

Adhesion

Answer 17

The process by which microbes gain a stronger foothold at the portal of entry

Question 18

Fimbriae

Answer 18

Short hair-like structures used in adhesion

Question 19

Capsules

Answer 19

Extracellular slime or stocky layer used in adhesion

Question 20

Viral spires

Answer 20

Attach to host receptors1 adhesion structure

Question 21

Hooks or flagella

Answer 21

Used for attachment/adhesion

Question 22

Virulence

Answer 22

Ability of microbes to invade a host, produce substances to evade host defenses, and bring damage to the host

Question 23

Virulence factors

Answer 23

Substances that improve the microbe’s ability to establish an infection and promote their invasiveness

Question 24

Virulence factors include

Answer 24

Physical structures, exoenzymes, antiphagolytic factors, and endo and exo toxins

Question 25

Exoenzymes

Answer 25

Used to get deeper into the host, enzymes made and secreted by microbes that disrupt the structure of the hosttissue

Question 26

Keratinase

Answer 26

Exoenzyme secreted by dermatophytes to digest the principal component of hair and nails

Question 27

Mucinase

Answer 27

Exoenzyme, factor in amoebic dysentery, digests principal component of mucus membranes

Question 28

Hyaluronidase

Answer 28

Secreted by staphylococcus and streptococcus to digest hyaluronic acid which is the ground substance cementing animal cells together

Question 29

Antiphagocytic factors

Answer 29

Leukocidins, glycocalyx, and intracellular survival

Question 30

Leukocidins

Answer 30

Toxic Substances Secreted by virulent strains of staphylococcus and streptococcus that kill WBCs Punch holes causing cells to lyse

Question 31

Glycocalyx

Answer 31

Extra cellular surface layers make it physically difficult for phagocytes to engulf them ( strep. pneumoniae, Neisseria meningitidis, Cryptococcus)

Question 32

Intracellular survival

Answer 32

Some bacteria are well adapted to survive inside phagocytes like chlamydia, mycobacterium, listeria, etc

Question 33

Toxins

Answer 33

Chemical products of an organism that have poisonous effects on other organisms

Question 34

Exotoxins

Answer 34

Secreted by a living bacteria cell into the infected tissue ( usually targets specific tissue)

Question 35

Endotoxins

Answer 35

Not secreted, released after the cell is damaged or lysed Usually found in cell wall and released upon death causing fever, shock, watery eyes etc

Question 36

Exotoxin properties

Answer 36

Made of small proteins, produced by gram neg and pos, released by live cells, toxic in small amounts, can be destroyed by heating, ingesting toxin or toxin secreted into tissues, specific to a cell type, quick illness variable recovery Food poisoning, diarrhea, paralysis, tissue damage

Question 37

Endotoxin properties

Answer 37

LPS and techoic acids, lipid/sugar based, LPS gram neg and TA gram plus, released from cell wall during lysis, toxic in higher doses, stable at higher temps, systemic Inflammation, bleeding, GI problems, shock Long incubation and recovery

Question 38

Incubation period

Answer 38

Time from initial contact with the pathogen to the appearance of the first symptom Majority of infections range 2-30 days

Question 39

Prodromal stage

Answer 39

Short period 1-2 days when the earliest notable symptoms appear Fatigue, head and muscle aches, upset stomach

Question 40

Period of invasion

Answer 40

Pathogen multipliesat high levels, exhibits greatest toxicity, becomes well established in target tissue

Question 41

Convalescent period

Answer 41

If patient doesn't die, respond to infection and symptoms decline, can be dramatic or slow recovery

Question 42

Localized infection

Answer 42

Pathogen confined to specific tissue Examples: boils, warts, fungal skin infection

Question 43

Systemic infection

Answer 43

Infection spreads to several sites through blood and lymph fluid Examples: viral diseases like measles and chickenpox, secondary syphillis, cryptococcosis in hiv/aids

Question 44

Focal infection

Answer 44

Infectious agent breaks loose from local infection and is seeded or disseminated into other specific tissues Examples: mycobacterium tuberculosis, Streptococcus pyrogenes,

Question 45

Mixed infection

Answer 45

Same site infected with several microbes at the same time Examples: animal or human bite infections, wound infections