host-parasite interaction Flashcards
association of two organisms living together; where both (host and organism) benefit from one another may be described as mutualism
symbiosis
relationship where the organism benefits but there is no beneficial or harmful effect to the host
commensalism (ex. proteus mirabilis)
one species (microbe) benefits at the expense of the other (host) (ex. entamoeba histolytica)
parasitism
microorganisms that are commonly found on or in body sites of healthy persons are called…
normal, usual, indigenous flora
microorganisms that colonize an area for months or years represent
resident microbial flora
microorganisms that are present at the site temporarily represent
transient flora (“visit”)
more organisms inhabit moist areas than dry areas; and are dominated by…
diphtheroids
human milk has a high lactose concentration and maintains pH of…
5.0 to 5.5; an environment supportive of bifidobacterium spp.
composition of the flora on the skin depends on the activity of
sebaceous or sweat glands
organisms concentrate the most in areas that are moist
such as armpit, groin, and perineum
this gland secrete substances metabolized by the skin bacteria, releasing odorous amines
apocrine sweat glands
found in moist areas such as axillae and between the toes
aerobic diphtheroids
colonize the deep sebaceous glands
p. acnes
reside in hair follicles and colonize the sebaceous glands because they are resistant to skin lipids and fatty acids
staphylococcus epidermidis, propionibacterium spp.
predominant genus of mouth bacteria
streptococcus
upper respiratory is composed of
mouth
nasopharynx
oropharynx
larynx
lower respiratory composed of
trachea
bronchi
pulmonary parenchyma
mouth, nasopharynx, oropharynx are colonized predominantly with viridans strep
such as streptococcus mitis, strep mutans, strep milleri, strep sanguis, moraxella catarrhalis, neisseria spp., and diptheroids
gastrointestinal tract comprises of
esophagus
stomach
small intestine
colon
microorganism resistant to acid ph of the stomach
spore-forming bacteria
cysts of parasites
helicobacter pylori
microorg present in large intestine
pseudomonas aeroginosa
gram-pos cocci
yeasts
colonized in its outermost segment by organism found on the skin
urethra
before puberty and postmenopausal women, vaginal flora primarily consists of…
yeast
gram-neg bacilli
gram-pos cocci
ability of a microbe to prduce disease in a susceptible individual
pathogenicity
organisms recognized to cause disease in healthy immunocompetent individuals
true pathogens
pathogenic in nearly all situation; and clinical significance is well established
yersinia pestis and bacillus anthracis
colonizes the upper respiratory tract of healthy individuals without causing disease
haemophilus influenzae
organisms under usual conditions do not cause disease but can induce an infectious process in patients with prostetic devices
staphylococcus epidermidis
oppurtunistic pathogens
h. influenzae and S. epidermidis
an infection that occurs as the result of medical treatment or procedures
iatrogenic infection
relative ability of a microorg to cause a disease or the degree of pathogenicity
virulence
virulence encompass functions such as
inhibiting phagocytosis
facilitating adhesion to host cells or tissues
enhancing intracellular survival after phagocytosis
damaging tissue thru the production of toxins and extracellular enzymes
encapsulated strains of… are associated with highly invasive infections and are known to be more virulent than nonencapsulated strains
s.pneumoniae
h. influenzae
another bacterial structure that protects organisms from phagocytosis is
protein A
protein A in the cell wall of staphylococcus aureus helps the organism avoid phagocytosis by
interfering with the binding of the host’s antibodies to the surface of the organism
antibodies bind to antigens via their
Fab or antigen-binding portion
protein A binds to the Fc portion of igG
preventing opsonization and phagocytosis by turning the antibody around on the surface
streptococci prduce… that lyse rbc and induce toxic effects on wbc and macrophage
hemolysin
pathogenic staphylococci release… that cause lysosomal discharge into cell cytoplasm
leukocidins
staphylococcal leukocodins… is lethal to leukocytes and contributes to the invasiveness of the organism
panton-valentine
cell surface structures that mediate attachment are called
adhesins
main adhesins in bacteria are the
fimbriae (pili)
causes traveler’s diarrhea
e.coli
