Pseudomonas infections Flashcards
exam 4
gram negative, highly motile, rod-shaped bacterium
Pseudomonas aeruginosa
P. aerugionosa, adheres tightly to
lung epithelium
P. aerugionosa, produces
extracellular polysaccharide (mucoidy)
P. aerugionosa, is the primary cause of death in
CF patients
enlargement of the airway space due to continuous damage
Bronchiectasis
Gram negative envelope contains in the periplasmic space [3]
- hydrolytic enzymes
- chemoreceptors
- Transport proteins
a phospholipid inner leaflet provides a
barrier to hydrophilic compounds
LPS in outer leaflet [2]
- negative charged surface
2. resistant to detergents and other hydrophobic molecules
allow entry of small nutrient molecules through outer membrane
Pores
Pores in outer membrane allow ____________ but not _____________ to enter the periplasm
Pores in outer membrane allow small (,700 MW) hydrophilic compounds to but not larger molecules like antibiotics to enter the periplasm
known as an endotoxin or O-Ag is a very potent antigen
LPS
LPS causes a strong innate immune response: ___________ and _________
cytokine production and septic schock
LPS causes a strong adaptive immune response: _______
serotyping of strains
found on microbial cell surfaces sand bind to sugars or proteins on the host cell surface
adhesins
adhesins can be ____________; some bind only to a single type of epithelial cel in a single animal species
remarkable specific
in some areas, including the human mouth, cell receptors and _____________ that bind them vary from one tiny area to another
adhesins
potentially adhesive structures of bacteria [3]
- Pili- fimbriae
- flagella
- capsules
H7
flagellum
O157
serotype
most common agent of motility
flagellum
allows bacteria to penetrate mucous layer
motility
movement towards food or away from poisons. Specific receptors on bacterial cell surface direct motility
chemotaxis
has a single, polar flagellum
P. aeruginosa
can be polar or all over cell
peritrichous
How does a bacterium know when and where
it should swim?
Bacterial chemotaxis and motility are controlled
by signal-sensing,“two-component”
regulatory systems
loose network of polymers surrounding cell and be either polysaccharide or protein or both
capsules
alginate of Pseudomonas
Mannuronate-guluronate co-polymer
role of capsules [4]
- resists drying
- promote adherence
- protects against phagocytosis
- protects against some environmental stresses
often capable of causing septicemia and meningitis
encapsulated bacteria
a polysaccharide excreted by P.aeruginosa
alginate
bacteria that produce large amounts of alginate are said to be
mucoid
alginate coats the bacterial cells forming a
capsule-like structure
protects P.aeruginosa against host defense sand antibiotics
alginate capsule
sigma factor for toxin gene transcription
TcdR
alginate production depends on _________ for transcription of alginate genes
AlgU
AlgU
alternative sigma factor
AlgU normally held in an inactive state by interaction with
MucA
When cells sense cell wall stress, ______ is degraded by a protease in the periplasm
MucA
When MucA is degraded, ____________ is freed and then can direct transcription of the alginate genes
AlgU
The lungs of CF patients accumulate mutant strains of P. aeruginosa that produce a truncated
inactive MucA
When the MucA is inactivated what happens to AlgU?
it is always active leading to high levels of alginate are produced= mucoidy
Why aren’t antibiotics effective in eliminating P. aeruginosa? [3]
- airway mucous is viscous
- mucoidy
- biofilm formation
Pod of bacteria
biofilm
Biofilm formation in nature,
Step 1
attachment- Fla+ and Pil+
Biofilm formation in nature,
Step 2
stable binding growth- Fla- and Pil-
Biofilm formation in nature,
Step 3
capsule synthesis- Alg+
Biofilm formation in nature,
Step 4
readying for release- Fla+ and Pil+
Biofilm formation in nature,
Step 5
planktonic bacteria- Fla+ and Pil+
over-production or under-production of alginate in CF?
over-production
intercellular signaling occurs [2]
- within a species or across species lines
2. withing populations of dispersed cells or in communities of cells
acylated homoserine lactones
gram-negatives
peptides
gram-positive
what happens in the absence of phosphorylated response regulator?
unstable recognition of promoter–> no transcription
Bacteria have __________ and ____________ capabilities that enable them to coordinate growth, movement and biochemical activities. These capabilities affect growth in many environments as well as _____________
Bacteria have communication and decision-making capabilities that enable them to coordinate growth, movement and biochemical activities. These capabilities affect growth in many environments as well as
pathogenesis
Communication and coordination are _________ and not limited to a few specialized groups of bacteria.
Communication and coordination are widespread and not limited to a few specialized groups of bacteria.
Bacterial populations derive adaptive benefits from ______________
multi-cellular cooperation.
In the presence of ______________, binds of regulator to DNA just upstream of RNA polymerase and stabilizes RNA polymerase binding to the promoter.
In the presence of phosphorylated response regulator binds of regulator to DNA just upstream of RNA polymerase and stabilizes RNA polymerase binding to the promoter.
bacteria sense if we have quorum to do something
quorum sensing
acylated homoserine lactones and peptides are
quorum sensing
histidine kinase
sensor receptor