microbio chapter 13 (copy)

equilibrium

equilibrium

the human body exists in a state of dynamic

biofilms

many interaction between human body and microorganisms involve the development of

“give and take”

colonization of the body involves a constant

microbes

provide a protective and stabilization effect on body surfaces; are involved in maturation of host defenses and development; can invade and grow in sterile tissues, causing disease

infection

pathogenic microorganisms penetrate the host defenses, enter the tissues and multiply

disease

the pathologic state that results when something damages or disrupts tissues and organs

infectious disease

the disruption of a tissue or organ caused by microbes or their products

resident biota

the human as a habitat

normal (resident) biota

microbes that engage in mutual or commensal associations with humans

normal (resident) biota

microflora, indigenous flora, microbiota

metagenomics

being used to identify the microbial profile inside and on humans; human microbiome project

host

any organism that harbors another organism

symbiosis

an association between 2 or more species

mutualism

both members of the association living together benefit for the relationship

commensalism

two species live together in a relationship such that one and the other one neither benefits nor is harmed

parasitism

one organism , the parasite benefits from the relationship, whereas the other organism, the host, is harmed

microbe-free

internal organs, tissue, and fluids are

resident microbes

most areas of the body in contact with the outside environment harbor

transients

microbes that occupy the body for only short periods

residents

microbes that become established

health, age, diet, hygiene, hormones, drug therapy

biota can fluctuate with

microbial antagonism

many times bacterial biota benefit the human host by preventing the overgrowth of harmful microorganism

compromised immune systems

hosts with ____ could be infected. by their own biota

endogenous infections

caused by biota that are already present in the body

microbe-free

internal organs and tissues and fluids are

just before birth when mucus plug come out

uterus and contents are normally sterile and remain so until

pathogen

a microbe whose relationship with its host is parasitic and results in infection and disease

pathogenicity

type and severity of infection depend on___of the organism and the condition of the host; an organism’s potential to cause infection

true parthogens

capable of causing disease in healthy persons with normal immune defenses

true pathogens

influenza virus, plague bacillus, malarial protozoan

opportunistic pathogens

cause disease when the host’s defenses are compromised or when they grow in part of the body that is not natural to them

opportunistic pathogens

pseudomonas sp and Candida albicans

skin

largest and most accessible organ

transients

cling to the surface but do not grow there; influenced by hygiene- multiply on top epidermis layer of the skin

residents

stable, predictable, less influenced by hygiene primarily bacteria and yeasts- multiply on the deep layer of the epidermis

dermis layer of the skin

no microbes should be present in the

GI tract

is a long hollow tube, bounded by mucous membranes; receives, moves, digest, and absorbs food and removes waste

oral cavity, esophagus, stomach, small intestine, large intestine, rectum and anus

GI tract includes

variations in flora distribution

due to shifting conditions like pH, oxygen tension and anatomy

cheek epithelium, gingiva, tongue, floor of mouth, tooth enamel

most diverse and unique flora of the body

S. sanguis, S. salivarius, S. mitis

the most common residents are aerobic streptococcus species

teeth eruption

establishes anaerobic habitat in the gingival crevice favoring colonization by anaerobic bacteria

fermentation of waste material in the feces

generates vitamins (B12, K, pyridoxine, riboflavin, and thiamine) and acids( acetic, butyric and propionic)

bacterial digestive enzymes

convert disaccharides to monosaccharides or steroid metabolism

skatole, amines and gases

contribute to intestinal odor

oral streptococci

first organisms to colonize

staphylococcus aureus

nasal entrance, nasal vestibule, anterior nasopharynx

neisseria species

mucous membranes of nasopharynx

assorted streptococci and haemophilus

tonsils ans lower pharynx

vagina and outer opening of uretha

sites that harbor microflora in females

anterior uretha

sites that harbor microflora in males

urine

kidney, urether, bladder and upper uretha kept sterile by

composition of normal flora

changes in physiology influence

normal flora

is essential to the health of humans; create an environment that may prevent infections and can enhance host

antibiotics, dietary changes, disease

may alter flora

probiotics

introducing known microbes back into the body

avoiding phagocytosis

avoiding death inside phagocyte

evading actions of the immune system

surviving host defenses

direct damage

toxins, enzymes, lysis

indirect damage

host response is inappropriate and excessive

virulence of the pathogen

severity of the disease depends on the

virulence factor

characteristic or structure that contributes to the ability of a microbe to cause disease; pathogenicity is dependent on this

portals of entry

characteristic route a microbe follows to enter the tissues of the body

exogenous agents

originate from source outside the body

endogenous agents

already exists on or in the body(normal flora)

portals of entry in skin

nicks, abrasions , punctures, incisions    

portals on entry in GI tract

contaminated food, drink and other ingested materials

portals of entry in respiratory tract

oral and nasal cavities

portals of entry in the urogenital tract

sexual, displaced organisms 

infectious dose(ID)

minimum number of microbes required for infection to proceed

greater virulence

microbes with small IDs have

infection

lack of ID will not result in

adhesion

microbes gain a stable foothold at the portal of entry; dependent on binding between specific molecules on host and pathogen

neisseria gonorrhoeae

gonorrhea; Type IV pili attach to genital epithelium. 

escherichia coli

diarrhea; Well-developed fimbriae adhere to intestinal cells. 

shigella and salmonella

gastroenteritis; Fimbriae attach to intestinal epithelium. 

vibrio cholerae

cholera; Glycocalyx anchors to intestinal epithelium.

infleunza virus

influenza; Viral spikes dock to respiratory receptors.

HIV

AIDS; Viral spikes adhere to white blood cell receptors.

exoenzymes

bacteria produce extracellular enzymes that dissolve and penetrate through or between cells to invade underlying tissues

toxins

secreted by bacteria damage target cells, which die and begin to slough off

blocked phagocytic response

bacteria have a property that enables them to escape phagocytosis and continue to grow and cause further infections

toxin

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

toxinoses

adverse effects of toxins

toxemias

when the toxin is spread by the blood from the site of infection (tetanus, diphtheria)

intoxications

caused by ingestion of toxins (botulism

endotoxins

not secreted, but released after the host cell is damaged- top of outer membrane of gram negative cells (LPS)

exotoxins

secreted by a living bacterial cell into the infected tissue; Strong specificity for a target cell, disrupting its membrane

hemolysis

disrupt membrane of red blood cells

A-B toxins

A-active ,B-binding

physiological effects of exotoxins and endotoxins

fever, malaise, aches, shock- released after cell is damaged, not specific 

toxoid

is an inactivated toxin used in vaccines.

antitoxin

is an antibody that reacts specifically with a toxin.

incubation period

time from initial contact with the infectious agent to the appearance of first symptoms; agent is multiplying but damage is insufficient to cause symptoms; several hours to several years

prodromal stage

vague feelings of discomfort; nonspecific complaints- headaches, muscle aches, stomach aches

period of invasion

multiplies at high levels, becomes well-established; more specific signs and symptoms- greatest toxicity, greater symptoms 

convalescent period

as person begins to respond to the infection, symptoms decline- going back to homeostasis/ normal. Getting better. If someone dies then its called terminal illness 

localized infection

microbes enter the body and  remains confined to a specific tissue- warts 

systemic infection

infection spreads to several sites and tissue fluids usually in the bloodstream- chicken pox, measles, syphillis

focal infection

when infectious agent breaks loose from a local infection and is carried to other tissues- tuberculosis 

mixed infection

several microbes grow simultaneously at the infection site -polymicrobial