Micro 106 Exam 5

what is enterotoxigenic

a toxin similar to cholera toxin, disturbs water balance in colon leading to diarrhea

what is the primary rule for vaccines

must provide protection but not cause the diesase

who created the first vaccine

* edward jenner
* variolation
* people were skeptical

how do vaccines work

inducing active immunity response

* antibodies against antigen
* memory cells

how can harless germs be bad?

get into places they do not belong and cause problems

what does it mean that we develope symbiosis with bacteria

* they don’t typically harm us
* immune system ignores
* possible bypass defense
* normal flora compete with more bacteria we may encounter

what is the pattern of infection

1. gain access
2. cause symptoms + potential damage / death

what is the name of something capable of causing disease?

pathogen

what is virulence

how dangerous a pathogen is

* most serious pathogen can for capsule or produce damaging toxins

when does an infection begin

when pathogen is first encountered

what is the study of how diseases are first transmitted in a population

epidemiology

does simple exposure of pathogen cause sickness?

no, pathogen must gain entry through “portal of entry”

what is endogenously

originating internally

are endogenously contracted infections communicable?

no

what is an endogenously contracted infection?

* individual makes self sick
* bacterial of normal flora gets to area it shouldn’t
* environmental exposure

what is an exogenously contracted infection?

* get and pass to others
* direct personal contact
* indirectly via food/drink/droplets in air
* fomite → inanimate object

are exogenously contracted infections communicable?

yes

what is a exogenously contracted infection?

comes from outside source

does an infectoin occur after pathogen makes it to the portal of entry?

no, needs to gain entry to deeper body tissues or hang onto mucous membrane

* must attach!

what are the 2 requirements for the pathogen to adhere?

1. receptor on cell surface
2. adhesion protein on bacterial cell surface

what are the mechanisms of pathogen adhesion?

1. fimbriae
2. capsules
3. spikes
4. hooks or flagella

how can pathogens end up in different parts of the body?

they can catch a ride on phagocytes

where do insects inject pathogens?

directly in blood

what can put pathogens deeper into tissue?

trauma

what is on the pathogen to do list?

* evade immune defense
* multiply
* spread out from initial invasion site

what impacts the first step of infection multiplying?

* depends on conditions of locations and generation time of pathogen

what is the incuabation period

time needed by pathogen to overcome early host defenses

* early on, host is infected but cannot transmit

latent period

subset of incubation period

* time until host becomes infectious, but before symptoms occur

what are intoxications?

food poisoning

what is food poisoning

* ingestion of bacterial toxins
* not considered infection but can be
* effect seen quickly
* not communicable

what is the critical phase?

* pathgoen using every truck to avoid/outpace immune system
* last chance to avoid disease (prior to symptoms)
* IMPORTANT

what are the tricks pathogens use to avoid destruction

* avoid/survive phagocytosis
* secrete leukocidins
* enzymes that degrade CT allowing cell to spread
* enzymes that attack IgA
* production of a capsule

what do symptoms mean?

indicate damage has already occurred

what does hyaluronidase do?

degrades main component of CT

what does collagenase do?

degrades collagen (in ct)

what does coagulase do?

causes fibrin to clot, depleting it

what does fibrinolysin do?

degrades fibrin

what does hemolysin do?

destroys RBCs

what do pathogens secrete?

endotoxins or exotoxins

exotoxins

* primarily produced by G+ bacteria
* protein has highly specific 3D shape
* tempt and pH
* highly antigenic (strong immune response)
* good vaccine candidate
* toxic
* target specific receptors

what is an enterotoxins

* subunit of exotoxins
* specifically target intestinal tract lining
* vomiting, diarrhea, cramping

what does an enterotoxin do?

* interfere with how much cells here process solutes
* too much liquid stays behind

what are endotoxins

* integral part of outer membrane of G- tract bacteria
* also called LPS
* stable
* causes fever in low doses

what is mechanical damage

parasite get into tubular systems and cause blockages

* blood vessels
* lymph vessels
* ducts

elephantiasis

what is the last step of the infection cycle?

portal of exit

* escape host and find new host

how does the host recover from the infection

* immune system
* antibiotics
* may be organ damage like meningitis

what is latency

dormant state of infection

what infections are prone to latency

* chicken pox
* hiv
* rabies

what is the natural habitat form pathogens

reservoirs

what are some living reservoirs

* animals
* humans
* arthropods

what are some nonliving reservoirs

* soil
* water
* air

what is the carrier state

* harbors pathogen
* can pass it along without knowing

what is an incubating carrier

when a person has an illness and can spread it

what is an asymptomatic carrier

when host is unaware of disease they carry because there are no symptoms

convalescent carrier

does not feel sick but still contagious

what is a chronic carrier

following recovering from illness

* person is healthy but may transmit

what is epidemiology

study of distribution of diseases and injuries in humans and what influences it

what is the purpose of epidemiology?

1. define distribution and size of disease prob
2. ID contributing factors in pathogens of disease/injury
3. provide basis for developing and evaluating prevention procedures

what information is important in epidemiology

* age
* rave
* gender
* socio-economic status
* marital status
* maternal age
* location
* time period

what are the two types of epidemics?

1. common source
2. propagated/progressive epidemic

what is a common source epidemic

* spikes in cases due to single event
* exposure due to non-communicable agent
* all cases come from that one time event

what is a propagated/progressive epidemic

* communicable agent

is streptococci G+ or G-

G+

what is streptococci

* pairs of chains
* facultative anaerobes

how is streptococci classified?

by looking at patterns on blood agar

what is m protein

very long structure resembling pili or fimbriae

* allows for surface attachment of bacteria

what is LTA (lipoteichoic acid)

virulence factor also aids in attachment

what is the hyaluronic acid-containing capsule

allows cell to avoid phagocytosis

what does strep do?

* produces enzymes and toxins
* digest CT
* degrade DNA and RNA

what is the pathogenic group a strep?

* responsible for a number of disease
* grouped by end result of damage
* overreaction of host defense
* dependent on portal of entry

what happens if the portal of entry is uterus

* puerperal fever

what happens if the portal of entry for s. pyogenes is skin

impetigo (contagious) or cellulitis

what happens if the portal of entry for s. pyogenes is throat

strep throat

what are 2 serious diseases that can be caused by group a strep

* acute glomerulonephritis
* rheumatic fever

what are enteric bacilli?

* G- rods, found in intestinal tracts of humans and animals
* few are true pathogens

what does shigella do?

cause of dysentery

what are the stains of enteric bacilli 3 antigenic markers

* H marker
* O marker
* K marker

what is the H marker

flagella

what is the O marker

cell wall antigen

what is the K marker

capsule

how can salmonella travel

oral-fecal route

* contaminated food / h2o

what are the 3 forms of disease associated with salmonella

1. enteric fevers (typhoid)
2. gastroenteritis (food poisoning)
3. septicemia (blood poisoning by bact)

what is typhoid

* few week incubation
* high fever

what is gastroenteritis

* from contaminated meat/poultry

what is shigella

* spread similarly to salmonella
* few cells need to be ingested
* short incubation

what is e coli.?

* predominant faculatative bact in GI tract
* can be consideredpart of intestinal flora
* 4 groups cause intestinal disease

what are the 4 groups of disease causing E coli.?

1. enteroinvasive
2. enterotoxigenic
3. enteropathogenic
4. enterohemorrhagic

what is enteroinvasive e coli.?

cells invade epithelial lining and cause a disease with symptoms similar to dysentery

what is enteropathogenic e coli.?

cell attachment disrupts normal function of epithelial lining

what is enterohemorrhagic e coli.?

strain produces a toxin similar to shiga toxin, dysentery symptoms

what is neisseria

* G- diplococci
* aerobic metabolism
* difficult to grow in lab

what are the 2 main pathogenic groups of Neisseria

1. Neisseria meningitidis
2. Neisseria gonorrhoeae

what are the hosts for meningitis

humans are the only host, must get it from someone who has it

how do you treat meningitis

penicillin

what is gonococcus

* STI → the clap
* inhibit mucous membrane of UT
* penicillin

what is yersinia

* plague / bubonic plague
* from flea bites

what is Bordetella

* UTR of humans and animals
* causes whooping cough

what is vibrio

* G- rods
* IT of humans
* ingestion of contaminated food
* issues come from fluid loss

what is legionella

* pontiac fever → less severe
* legionellosis → more severe

what is spriochetes

curvy shape