15: Microbial Mechanisms of Pathogenicity Flashcards
the ability to cause disease in a host
pathogenicity
relative degree of pathogenicity
virulence
which is more virulent, neisseria meningitidis or haemophilis influenzae
neisseria meningitidis
the avenue by which a microbe gains access to the body
portal of entry
what is the portal of entry for malaria plasmodia
bites through the skin
what is the portal of entry for aemeobic dysentery
ingestion of cysts
mucous membranes line the surface of the eye
conjunctiva
easiest and most frequently used portal of entry for pathogenic microbes
mucous membranes of the respiratory tract
some microbes can gain access through sweat glands and hair follicles, example
pseudomonas can cause folliculitis
when microbes enter the body by means other than the digestive tract
parenteral route
some microbes cannot cause disease unless they enter the body through their ______
preferred portal of entry
this disease enters the body through a parenteral route and has reverse transcriptase enzyme. what is the disease, and what would you call the syringe
HIV, fomite
the initial number of microbes which gain entry and is often decisive in determining whether active disease will follow
infecting dose of microbes
the attachment between pathogen and host is accomplished by means of surface molecules on the pathogen called _____ that bind specifically to complementary surface ___ on the cells of certain host tissues
adhesins, receptors
the majority of adhesins are what?
glycoproteins or lipoproteins
the host’s cell receptors are typically what?
sugars (mannose)
mats of microbes that represent another method of adherence and are important because they resits disinfectants and antibiotics
biofilms
most important virulence factor for bacterial pathogens
formation of a capsule
capsules interfere with ______ and increase the likelihood of microbial survival
phagocytosis
a host may make these against an encapsulated bacterium to make it more easily destroyed
anticapsular antibodies
components of the ____ may also help a microbe to resist phagocytosis
cell wall
component of cell wall in gram negative bacteria that help microbe resist phagocytosis
lipopolysaccharide
waxy lipid of mycobacterium tuberculosis that combats digestion after phagocytosis
mycolic acid
found on the surface of streptococcus pyogenes that helps to resis phagocytosis
M protein
produced and released by some bacteria that contribute to their virulence
enzymes
bacterial enzymes which clot fluid portion of blood (plasma)
coagulases
what bacteria is very good at producing coagulase
staphylococcus aureus
the ____ produced by coagulase may isolate the bacteria from the host defenses
fibrin clot
enzyme which break down blood clots
bacterial kinases
bacterial enzyme that has been used to help people with heart attack or strokes, what bacteria produces it
streptokinase, streptococcus pyogenes
______ is an enzyme which dissolves the cement like material _____ which holds cells together
hyaluronidase, hyaluronic acid
promotes the spread of the pathogenic microbes
hyaluronidase
_____ is an enzyme which breaks down the protein which forms the framework of muscles and several other tissues ____
collagenase, collagen
gram-positive, endospore-forming bacilli that are very good at producing hyaluronidase, collagenase, and hemolysin
clostridium perfringens (gas gangrene)
protein that lyses blood cells
hemolysin
destroys the protective IgA antibodies on mucous membranes
IgA protease
microbes can avoid the immune response by the host by changing the identifying markers on their surface (antigens). Thus, by the time the body mounts an immune response against a pathogen, the pathogen already altered its antigens and is unaffected by the immune response
antigenic variation
example of antigenic variation
influenza virus has neurominidase (N spikes) and H spikes that are adhesins and antigens
