Micro bio test 4

where does normal microbiota present on the human body

skin, gi tract, respiratory tract, oral cavity, urogenital tract

virulence

how harmful a pathogen is

what do you need to consider for a microbial habitat

physicochemical enviroment: ph, amount of oxygen, water activity, stability, and other microbial co inhabitants

do bacteria need us to survive

no

why do bacteria colonize humans

all bacteria need nutrients and most need heat to allow them to multiply and we are “free lunch” for them

we give them a stable environment without hurting them

how do humans benefit from bacterial colonization

most are neutral or beneficial to humans

some neutral bacteria are occupying a spot that would otherwise be occupied by pathogenic bacteria

without our defense systems bacteria may become problematic to humans (immunocompromised pts)

bacteria also produces essential coenzymes

symbiosis

human is the normal habitat

mutualism

beneficial effects for both bacteria and human

parasitism

bacteria is the only one who is being positively impacted

human is being negatively impacted

commensalism

no clear effect

transient

not a specific or long term interaction

commensals

normal microbiota

colonization at birth from mother or from environment soon after birth (obtained through birth canal)

may change during development

what is one of the first microogranisms a baby gets- particularly from breast and milk

lacto bacili

opportunistic pathogens

can cause disease under certain conditions- host being immunocompromised,

pathogens

organisms that cause disease (damage or injury to the host that impairs host function)

pathogenicity

ability to cause disease

virulencey (higher=more ability) (lower=less ability)

infection

microbe is established and growing in a host

whether or not the host is harmed

when does infection turn into disease

after it starts causing harm

can micro flora change

yes as the human body grows, lifestyle, diet

people who live in the same household would have similar microflora

mutualism

best known examples are in intestine (vitamine synthesis, organic acid production, steriod metabolism)

skin

pH 4-6

some oxygen status

low water activity

not stable

which microogranisms live on the skin

resident and transient

why is skin a good barrier

because if a microorganism was living on the skin w ph of 4 and then there is a cut, the inside of the bodys ph is 7 so it is unlikely the organism can live on both ph’s

epidermis habitat

limited water activity

lots of transient organisms

non growing or slowly growing commensals

lots of gram positives

where are aprocrine (sweat) glands found

underarms, genitals, nipples, and umbilicus

when do aprocrine glands become active

at puberty

where is there a low concentration for TEA for anaerobes

apocrine glands

what are odors products of

fermentation

how many species of bacteria is there in the skin

180

what are the four dominant genera

streptococcus

staphylococcus

corynebacterium

Propionibacterium

streptococcus

aerotolerant anaerobe (lactic acid bacteria)

homofermentative

important in food production (yogurt, buttermilk)

streptococcus pathogen

endocarditis- infection of the heart valve tissue

swim through our bloodstream and accumulate on heart valve (filium) and cause pieces of heart valve to break off and become leaky- have to have these wounds for a long time, common to start from gum disease

propionibacterium (actinobacteria)

obligately anaerobic- live in sweat glands

ferment lactic acid and carbs

implicated in acne

used to make swiss cheese- Co2 makes the holes

staphylococcus

facultative anaerobe

skin diseases- MRSA

corynebacterium

obligately aerobic or facultatively anaerobic

cell ends often swollen

diphtheria

gastrointestinal tract

get microorganisms by food, upper respiratory system drainage (post nasal drip)

habitats are relatively stable- hard to shift it permanently

hosts 10 × 14 prokaryotic cells

which tract has the highest variety and number

gi tract

with 1000 species (but not all just in one person)

are there more or less bacterial cells in the gi tract

10x fewer cells than bacterial cells

stomach

acids act as a barrier to colonize by ingested bacteria to colonization

helicobacter pylori is most common, it can cause ulcers, may be associated w stomach and pancreatic cancer; inflammation

small intestine

ph increases 4-5 and bacterial counts increase

mainly enterococci and lactobacilli (organisms we get to breakdown milk related products- yogurt)

large intestine

large surface area with high concentrations of bacteria and archaea

most are strict anaerobes

microbes produce vitamin k, b12 (produced by bacteria and absorbed in intestine)

Central nervous system

vagus nerve

circulatory system

immune system

circulatory system

neurotransmitters

hormones

metabolites

immune signaling

immune system

MAMPS

metabolites

what can altered gi tract microbiota, via interaction with host cells may result in

long term low grade inflammation

can also play a role in a variety of conditions like obesity

what filters in the respiratory tract

cilia

what grabs bacteria on the way down to the lungs

mucous

are the lungs sterile

yes

they are not normally colonized

is the bladder sterile

yes but the urethra epithelial cells may be colonized

how many microbiota species are there in the oral cavity

200

characteristics of mouth microbiota

smooth enamel is difficult to colonize

edge of gingiva is a good habitat bc food gets trapped and tartar attaches to enamel which is a good attachment substrate for bacteria

mixed acid fermentation by lactic acid bacteria produces what

lactic acid which slowly makes the enamel more softer which leads to cavities

importance of sucrose

most caries are caused by Streptococcus mutans. Degradation sucrose produces dextran polymer, a strongly adhesivepolysaccharide that aids in attachment (biofilm formation and strengthening)

plaque is

biofilm- slime layer

how does brushing help the teeth

removes microbial biomass

decreases volume of anaerobic microenvironment for acid formation

hydroxyapatite

major mineral component of tooth enamel

fluoroapatite

converted hydroxyapatite by exposure to fluoride ions in toothpaste and treated water

harder and more stable in acidic conditions

gongivitis

inflammation of gum tissue

can lead to destruction of tissue and bone

anaerobic prophyromonas gingivalis

its LPS (as endotoxin) is a key component of development of gingivitis

what is needed in order for gingivitis to happen

a list of other microorganisms that need to colonize in the mouth (prefanomas gingivialis)

enamal

tooth surface

coccostulates

believe to have a disease so we get a culture of it and put it in a healthy individual to see if they grow the disease

2 levels of human body defenses

non specific- 1st line- always present

specific defenses- produced in response to invasion by specific infectious agent

types of non specific defenses

physical and chemical barriers

phagocytes, unactuated macrophages, and natural killer cells

physical and chemical barriers- 1st line of defense

skin, epithelial cells, mucin, stomach acid, antimicrobial peptides

non specific

universal antimicrobial peptides

lysozyme in tears to help fight inflammation

non specific

specific defenses

antibodies, cytotoxic t cells and activated macrophages

human behavior: handwashing, taking entire prescription of antibiotics

probiotics

live cultures of bacteria that may have a beneficial effort to recolonize with normal microflora after antibiotic treatment

LD 50

a measurement of how virulent

lethal dose 50%

the number of bacteria at which 50% of those infected die

removes outliers

the lower the LD50 amount left the more pathogenic

attenuated

when laboratory growth of virulent strains often result in selection for mutants that lose virulence factors

often used for production of vaccines

toxicity

ability of an organism to cause disease by a preformed toxin

inhibits host cell function or kills host cells

invasiveness

ability of an organism to grow in host tissue in such large numbers that it inhibits host functions

what does some e coli have that allows for adherance

capsule

what does neisseria gonorrhoeae have to help facilitate binding to epithelium

pili

exotoxins

extracellular toxin (usually protein) produced by growth of a pathogen, results in immediate host cell damage

enterotoxins

exotoxins that specifically affect the small intestine

endotoxins

usually lipopolysaccharide (LPS) portion of gram - cell envelope, released on cell lysis (not growth) as a soluble toxin

how toxic is exotoxins

highly toxic sometimes fatal

can be destroyed by heat

how toxic are endotoxins

weakly toxic

cytotoxin

inhibits host cell protein synthesis

calcium influx into host

adherence

chromosomes SPI

salmonella pathogenicity islands

true or false: salmonella are able to invade and survive instead of macrophages

true

instead of being destroyed

examples of exotoxins

vibrio cholerae enterotoxin

staphylococcal alpha toxin

diphtheria toxin from corynebacterium diphtheriae

what is the most toxic toxin

botulinum

found in soil and gets to food sometimes, very potent

LD50 0.03

vibiro cholerae

exotoxin

causes disease by attaching to intestinal epithelial and releasing an enterotoxin

have a lot of salt and water moves there, water from blood stream moves to small intestine—- leading to diarrhea

staphylococcal alpha toxin

cytolytic exotoxin

they oligomerize (make a pore and the inside leaks out for bacteria to enjoy)

lysing

breakdown of cell membrane

diphtheria

protein AB exotoxin

A part attaches to EF2 (elongation factor) effecting translation, stopping it from working: if the cell cannot make proteins than the cell will die

the modified form is nonfunctional: protein synthesis is inhibited

symptom

a change in body function that is felt by a pt as a result of a disease

sign

a change in body that can be measured or observed as a result of a diseases

syndrome

a specific group of signs and symptoms that can accompany a disease

communicable disease

a disease that is spread from one host to another

contagious disease

a disease that is easily spread from one host to another

non communicable disease

a disease that is not transmitted from one host to another

incidence

a fraction of a population that contracts a disease during a specific time

prevalence

fraction of a population having a specific disease at a given time

sporadic disease

disease that occurs occasionally in a population

endemic disease

disease sonstantly present in a population

epidemic disease

disease acquired by many hosts in a given area in a short time

pandemic disease

worldwide epidemic