Bacterial Pathogenesis I Flashcards
HGT: Bacterial trasnformation
release of DNA
HGT: Bacterial transduction
release of Phage
HGT: Bacterial conjugation
Cell to to cell
Three types of horizontal Gene Transfer
transformation
transduction
conjugation
transformation, bacteria that are able to take up DNA are said to be
competent
example of bacteria that trasnformation all the time
bacillussubtilis and streptoccus pneumoniae
most naturally compete bacteria take up _____ DNA but not ______ _____ or ____ DNA
linear, circular plasmids, phage
example of prophage that can carry important fitness and virulenced terminants
diphtheria toxin
cholera toxn
pili
surface-modifying exnzymes
Generalized transducing phage transfer their DNA from one from bacterium to another during
lytic phase
Generalized transducing phage can accidentally package ______ when assembling virus particles
part of bacterial geome
Specialized Transducing phages undergo
both lytic and lysogenic phase during their life cycle
Specialized Transducing phages can move bacterial DNA that flanks phage attachment sites whenthey
excise their genome and exit the lysogenic phase
Plasmid Types
Fertility F-plasmids
Col plasmids
Virulence plasmids
Resistance (R) plasmids
Fertility F-plasmids contain
tra gene for transfer.
fertility F-plasmids are capable of
conjugation and result in the expression of sex pili
Col plasmids contatin
genes that code for bacteriocins. some are toxic to host cells
bacteriocins are
proteins that can kill other bacteria
Virulence plasmids encode
virulence factors, can convert a bacterium into a pathogen
Resistance (R) plasmids contain genes that
provide resistance against antibiotics or poisons
pathogenicity islands are
many virulence genes in compact, distinct genomic islands
pathogenicity islands differ in ___ than rest of bacterial chromosomes
G + C %
pathogenicity islands are made by
horizontal gene transfer
Factors that facilitate bacterial infection and survival with in a host
- attachment to host cell and tissue via adhesins
- evasion of innate and adaptive resonses
- acquisition of limityin nutrients- iron, amino acids
- dissemination with host and transmission to new host
- ability to outcompete commensals at many stages
the two types of bacterial adherence mechanisms
- Pili-dependent adhesions
- Pili-independent adhesion
bacteria that primarily reside in the extracellular milieu possess
virulence factors that prevent uptake and destruction by phagocytes
bacteria that primarily reside within host cells posses factors that
promote survival in the potentially inhospitable location
some bacteria strike a balance between
these locations and stringently regulate virulence factor expression
Survival of extracellular pathogens
- capsules
- mask deposited C3b
- vary antigenic surface exposed antigens
- secretion of molecules that interfere with host defenses (ex toxins and enzymes)
Listeria monocytogenes is gram
positive cultivate anaerobe
Listerial internalins InIA and InIB engage surface receptors and trigger
actin reorganization and signaling cascade activation
Nutritional Immunity limits
the establishment or growth of microbial pathogens within the host by restricting access to essential nutrients
Things that microbes use as a resource
metals/cations ( eg Fe, Mn, Zn, Cu,Mo)
amino acids
carbs
oxygen and alternate electron acceptors
the three bacterial strategies for evading amino acid starvation
- reticulate bodies -> aberrant bodies (go dormant)
- make its own amino acids
- polyUb, uses host protiens?
iron binding protein
enterobactin
what is toxic to host cells that is produced sommensals
H2S
