MICROBIOLOGY CHAPTER 14

pathology

Scientific Study of disease - concerned with etilogy (cause) and pathogenisus (development)& effects of disease

Name 3 types of symbiotic relationships

Mutualism, commenalism, parasitism

mutualism

both organisms benefit from the relationship

commensalism

one organism benefits from relationship and the other neither benefits or is harmed

parasitism

1 organism benefits and 1 is harmed Eg Salmonella enteric a receives food/warmth from Lrg Int and Human host experiences gastroenteritis

name 2 examples of mutualism

trichonympha in termite intestine and vitamin synthesizing bacteria in colon

name an example of commensalism

staphylococcus sp. on human skin

Define Disease

Any change from a state of heath. A disease may, but not always, result from infection

normal microbiota

organisms that colonize body surfaces w/o causing disease, (ex Streptococcus in mouth)

transient microbiota

present for a few days/week , are easier to get rid of than normal flora (eg microbs picked off door handle)

where are resident microbiota found

on skin, mm of digestive tract, upper respiratory tract, and distal part of urethra and vagina

most resident microbiota are _______

commensal

where are transient microbiota found

on skin, mm of digestive tract, upper respiratory tract, and distal part of urethra and vagina

why cant transient microbiota persist in the body

competition from other microorganism, elimination by body's defenses cells, chemical or physical changes in the body

when does normal microbiota develop

in the birthing process

when is resident microbiota established

first months of life

opportunistic pathogens

normal microbiota or harmless microbes that can cause disease under certain circumstances

name 3 conditions that provide opportunities for pathogens

immune suppression, reduction in microbial antagonism, intro of normal microbiota into unusual site in the body

name an example of normal microbiota in unusual site

ecoli in urethra causing uti

name 4 portals of pathogen entry

skin, mm, placenta and parenteral route

parental route

deposition directly into tissues under the skin or mm

name some ways pathogens enter by parental route

punctures, cuts, deep abrasions and surgery

adhesion

process by which microorganisms attach themselves to cells

is adhesion required to sucessfully est colonies within a host

yes

name adhesion factors

specialized structures, adhesins and attachment proteins

where are adhesion discs found

some protozoans

where are hooks and suckers found

in some helminthes aka worms

where are adhesins found

in bacteria

where are attachment proteins found

viruses

what are ligands

surface lipoproteins and glycoproteins that enable bacteria and viruses to bind to complementary receptors on host cells

avirulent

harmless unable to make adhesins or attachment proteins

what is disease also referred to as

morbidity = any change from a state of good health

asymptomatic infections

lack of symptoms but may still have signs of infection

etiology

study of cause of disease

who developed a set of postulates that must be satisfied to prove a particular pathogen causes a particular disease

robert koch

name 2 difficulties in satisfying kochs postulates

diseases that can be caused by more than one pathogen , pathogens that are ignored as potential causes of disease

name 3 diseases that can be caused by more than one pathogen

pneumonia, meningitis, and hepatitis

virulence

degree of pathogenicity

name 5 virulence factors

adhesion factors, biofilms, extracellular enzymes, toxins, and antiphagocytic factors

what are extracellular enzymes

enzymes secreted by the pathogen that dissolve structural chemicals in the body and help pathogen maintain infection, invade further, and avoid body defenses

hyaluronidase

extracellular enzyme that breaks down hyaluronic acid which holds animal cells together

collagenase

extracellular enzyme that digests collagen

coagulase

extracellular enzyme that causes coagulation to surround bacteria and protect them from body defenses

kinases

extracellular enzyme that breaks up blood clots, enabling bacteria to spread

name 2 types of toxins

exotoxins, and endotoxins

exotoxins

proteins or peptides secreted by microorganisms that destroy host cells or interfere with their metabolism

name 2 types of exotoxins

cytotoxins, and neurotoxins

cytotoxins

kill host cells or impair their ability to function

neurotoxins

adversely affect nerve cell function

name 2 pathogens that secrete neurotoxins

clostridium tetani, and clostridium botulinum

enterotoxins

adversely affect cells lining the gi tract

name 2 pathogens that secrete enterotoxins

staphylococcus aureus and escherichia coli

endotoxins

lipid portion of lipopolysaccharide of outer membrane of gram - bacteria released when cells die

antitoxins

antibodies that bind to toxins and neutralize them

name two factors that prevent phagocytosis by the host's phagocytic cells

bacterial capsule and antiphagocytic chemicals

how does a bacterial capsule stop phagocytosis

made up of chemicals found in the body so it is not recognized as foreign also it is slippery

how do antiphagocytic chemicals stop phagocytosis

prevent fusion of lysosomeand phagocytic vesicles to block digestion of microbe

what helps streptococcus pyogenes resist phagocytosis

m protein on cell walls and fimbriae

what are the five stages of infectious disease

incubation period, prodromal period, illness, decline, and convalescence

incubation period

time between infection and appearance of first symptoms or signs of disease

prodromal period

short time with only mild symptoms before illness

illness

time of most severe symptom and signs host immune response not at its maximum

decline

time when immune response peaks and or medical treatment overcomes pathogen

convalescence

time when host recovers tissues repaired and body begins to return to normal

is the host usually infectious during all stages of disease

yes

how does a pathogen leave the host

by portals of exit many of the same portals of entry

what are reservoirs of infection

sites where pathogens are maintained as a source of infection

name 3 types of reservoirs

animal reservoirs, human carriers, and nonliving reservoirs

zoonoses

diseases that are naturally spread from their animal host to human host

name 3 ways to acquire zoonoses

direct contact with animal or its waste, eating animals. bloodsucking arthropods

infectious disease transmission

transmission form either a reservoir or from hosts portal of exit

name 3 groups of infectious disease transmission

contact transmission, vehicle transmission, vector transmission

name 3 catergories of contact transmission

direct, indirect, and droplet transmission

what is direct contact transmission

person to person or animal reservoir to human

what is indirect contact transmission

pathogens spread from host to host by fomites

what are fomites

contaminated inanimate objects

what is droplet contact transmission

pathogens carried within respiratory droplets that exit the body by sneezing, coughing, and exhaling

how far do droplet transmissions travel

less than one meter

name 3 types of vehicle transmission

airborne, water-borne, and food-borne transmission

airborne transmission

spread of pathogen to respiratory mucous membranes via aerosols.

name some airborne transmission pathogens

staphylococcus, streptococcus and mycobacterium tuberculosis

water-borne transmission

spread of pathogen via contaminated water

name some water-borne gastrointestinal diseases

cholera, giardiasis, amebic dysentery

food-borne transmission

spread of pathogens in or on food

name 2 vector transmissions

biological and mechanical vectors

what are biological vectors

those that serve as a host for multiplication fo the pathogen, as well transmitting it

name some examples of biological vectors

ticks, blood sucking flies, mites, lice, fleas

mechanical vectors

those that transmit pathogens passively by carrying them on their body parts

name some examples of mechanical vectors

houseflies and cockroaches

what can houseflies and cockroaches carry

salmonella and shigella

name four methods of infectious disease classification

body system they affect, taxonomic groups of causative agent, longevity and severity, and how they are spread to a host

acute disease

one that develops rapidly and lasts a short time ex. common cold

chronic disease

one that develops slowly and last a long time ex. hep c, tuberculosis, leprosy and mono

subacute disease

one with a duration and severity between that of acute and chronic disease ex subacute bacterial endocarditis

latent disease

one that appears a long time after infection due to the inactivity of the pathogen ex herpes infection

communicable disease

one transmitted from an infected host directly or indirectly to another example influenza, herpes

noncommunicable disease

one not spread from host to host. ex tetanus, botulism, acne, and tooth decay

primary infection

initial infection within the host

secondary infection

one that follows primary infection, and may be caused by an opportunisitic pathogen

epidemiology

study of where and when diseases occur and thow they are transmitted within populations