BACTERIAL GENETIC&PATHOGENESIS Flashcards
prokaryote is haploid while eukaryote is diploid
chromosomes number bcs it is thru binary fission
genome of bacteria
two chain of nucleotides , double helix and has backbone of deoxyribose and phophates residues arranged strands,hold together by hydrogen bond
components of bacteria
single circular DNA molecule, no intons, histones,
extra chromosomal hv bacteriophage : intracelullar parasites that multiply inside bacteria by making use of host biosynthetic machinery
plasmid : carry gene for antibiotic resistance and enhance pathogenecity, circular DNA molecules found in cytoplasm
transposons : small segments of DNA that inserted within genes of chromosomes
what is mutation ?
change in the sequences of nucleic acid of DNA that can be inherited
3 principle of mutation
sponteneuos
mutagen-induced - induced by UV rays and chemical
transposones - jumping of foreign DNA into the genome
what is mechanism of bacteria acquire drug resistance ?
mutation -modification of target sites
genetic transfer - transformation, transduction,conjugation
several biochemical mechanism -limiting drug uptake, enzymatic inactivation, attaining the alternative pathways
what is normal flora ?
permanent residents of body sites and mucous membrane of healthy host not caused disease
example of commensals microorganism ?
neisseir meningititis
what is primary/true pathogen?
microorganism cause disease in immunocompetent (healthy normal ppl) and immunocompromised that hv virulence factor ex : candida albicans
what is oppurtunistic pathogens ?
microorganism cause disease in immnunocompromised people , it dont hv virulence factor
lactobacillus is used for ?
protect an prevent growth of yeast by producing hydrogen peroxide so increase lactic acid and decrease pH in vagina
streptococcus mutant function in mouth dental plaque?
maintain intracelullar pH
normal flora in skin ?
staphylococcus epidermidis tht prevent colonization by pathogens and possible disease thru bacterial interference
normal flora in colon and intestine
bacteroides fragilis
e.coli
fx of normal flora in GIT
produce polysaccharide A which activate immune response
list virulence factor of structural components
protein A -prevents opsonization and protect from host immune system
M protein
polysaccharide capsule -inhibits phagocytosis by neutrophils
list virulence factor of enzyme
IgA protease-destroys igA and enter the respiratory tract
coagulase -protect from phagocytosis
streptokinase(fibrinolysin) -activate production of plasmin
hyaluronidase -hydrolyse hylauric acid and enters the tissue
list virulence factor of toxin
diptheria toxin
botulinum toxin -blocks Ach
vibrio cholerae -activates adenyl cyclase y ADP-ribosylation
state the stages of microbial pathogenesis
1- entry of pathogen according to MOD 2- attachment 3- multiplication 4- invasion 5- evasion of host defense 6- damage of host tissue
endotoxin is gram + or gram - bacteria ?
gram - bcs it has outer membrane of lipopolysaccharide lipid A
exotoxin can stimulate antibody production and convert to toxoid
yes and it has high toxicity and unstable in temp above 60’c
exotoxin or endotoxin cause fever ?
endotoxin bcs it is low toxicity
exotoxin are made up of ?
polypeptide
which is the true concerning DNA ?
DNA is contained only in nucleus of cell (prokaryote)
movement of DNA from one bacteria to another thru pilus is
conjugation
CONS is from intact skin it is normal flora
staphylococcus aurens is from abcess in skin it is called ?
pathogen
what is carrier ?
person who have the microorganism but dont have symptoms of disease and can spread
characteristic of bacterial capsule ?
important mechanism for protection of bacteria against ingestion by neutrophils , it is from polysaccaharide
organism that causes endogenous infection in an immununocomprommised patient on antibiotic treatment ?
candida albicans bcs it is normal flora and fungus survive in antibiotic, antibiotic shows treatment for ONLY bacteria
what part of LPS responsible for toxic effect
lipid A
