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70 Cards in this Set
- Front
- Back
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Pseudomonas characteristics |
Gram negative Rod Non-fermenting Motile with pili and flagella Inhabits soil and water Opportunistic |
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When does P aeruginosa cause disease? |
Local or systemic breach in immune system - corneal abrasions, burns, surgical wounds - puncture wounds - osteomyelitis/cellulitis - chronic cutaneous ulcers in diabetics - Sepsis possible if immunocompromised |
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Pseudomonas Respiratory tract risk factors |
Immunocompromised, NEUTROPENIC Chemo, ventilator associated COPD, CHF Cystic Fibrosis |
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Cardiac system Pseudomonas |
Prosthetic heart valvs IV drug use |
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Central nervous system pseudomonas |
Trauma, surgery |
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Ear pseudomonas |
Diabetes and age Injury, maceration, inflammation Wet or moist conditions |
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Cornea and eye pseudomonas |
Injury extended wear of contacts |
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Bone and Joint pseudomonas |
Puncture/trauma IV drug use |
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Bacteremia/Septicemia |
Immunocompromised status - diabetes - immunodeficiency - neutropenia - burns |
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Urinary tract pseudomonas |
Obstruction, catheterization, surgery |
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GI pseudomonas |
Immunocompromised portal for bacteremia |
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Skin and soft tissue pseudomonas |
Burns, puncture, trauma Contaminated hot tubs |
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ALL patient Pseudomonas |
chemotherapy related
Mild respiratory distress w/ clear lung fields CVC due to IV meds, intact and dry skin without redness Third gen cephalosporin and tobramycin (aminoglycoside) Shock and sepsis, BP meds Delayed next round of chemo to let immune system recover |
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CF pseudomonas |
Chronic cough with yellow green sputum
Crackles heard throughout lung with increased interstitial and peribronchial markings Cystic fibrosis - sweat chloride test - IV ceftazidime and tobramycin for pseudomonas CF is autosomal recessive - affects GI, respiratory, pancreas - high concentrations of electrolytes in sweat - antibiotics down regulate virulence factors of P aeruginosa |
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P aeruginosa in CF patients has a _____________ appearance due to _____________ |
mucoid appearance Alginate capsule - evades host immune response P aeruginosa rarely causes sepsis in CF patients |
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P aeruginosa is ______________, non fermenting, motile gram negative rod |
Aerobic Persist in marginal environments |
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Pseudomonas is oxidase _________ |
positive |
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Pseudomonas energy |
Oxidation of sugars Can use nitrate anaerobically as terminal electron acceptor |
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Nutritional requirements |
Acetate - carbon ammonia - nitrogen Cannot break down polymers into monomers and thus cannot use lactose or sucrose |
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Water soluble pigments |
Pyocyanin - blue pyoverdin - green Fruity, grape like, or corn tortilla like color on plates |
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Pseudomonas pili |
Polar Adherence, twitching motility Biofilm formation and colonization |
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Flagellum |
Polar motility, adherence dissemination and initiation of the innate immune responses |
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Siderophores |
Pyoverdin and pyochelin - Secreted - Scavenge iron - acquisition of iron |
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Pyocyanin |
Generates ROS - blue color - Tissue damage |
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Exotoxin A |
ADP ribosylation of EF-2 Inhibits host cell protein synthesis |
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Exoenzymes |
TYPE III secretion system - interaction with components of host cell cytoplasm - Cytotoxicity, tissue damage, antiphocytosi |
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Elastase |
Proteolysis of proteins - elastin - collagen - immunoglobulins - complement components Tissue damage |
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Proteases |
Proteolysis Tissue damage |
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Phospholipases |
Hydrolysis of phospholipids - tissue damage, obtaining phosphate |
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Rhmanolipid |
BIOSURFACTANT - hemolysin - dispersion of biofilms |
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Alginate polysaccharrides |
Adherence, protection from dehydration, immune evasion Antiphagocytic, biofilm formation |
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Lipopolysaccharide |
Lipid A is EXOtoxic Core interacts with CFTR O antigen protects from complement mediated killing Sepsis, internalization, serum resistance |
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Encounter and entry |
Water, soil, vegetables, sinks, drains, wet surfaces, endotracheal tube, catheters Normal intestinal flora microbiota/skin |
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P aeruginosa ________________ adhere to intact epithelium |
DOES NOT |
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Infection of the hair follicle from hot tubs |
folliculitis - large inocula overwhelm the normal defenses |
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Swimmers infection |
otitis externa - benign or can progress |
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Immunocompromised P aeruginosa |
Lung - pneumonia
GI, catheter related infections - bacteremia GI especially when NEUTROPENIC |
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Modes of motility |
Flagella mediated motility Twitching motility - extension and retraction of polar pili Swarming ability - pili and flagella |
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Besides motility, flagella and pili regulate _____________ via interactions with ______________ |
Adherence Asialo- GM1 Flagella interact w/ TLR-5 to initiate inflammatory response |
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Type __________ pili are important in biofilm formation |
type IV |
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biofilm structure |
Held together by polysaccharides and proteins that are responsibe for adherence to surfaces, protection from dehydration, increased antibiotic resistance |
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_______________ can act as an adhesion that offers protection from immune response seen most in CF patients |
Alginate polysaccharide |
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Lipid A portion of LPS |
Interacts with host TLR4 to initiate host immune response - host inflammatory production of acute phase proteins, fever, hypotension Generally less inflammatory than other Lipid A of gram negs |
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Core polysaccharide of LPS |
Interacts with CFTR on epithelial cells that leads to bacterial internalization and initiation of innate immune resistance to pathogen |
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O antigen of LPS |
Resistance to normal human serum, detergents and some antibiotics Pseudomonas lacking O antigen can be killed by human serum |
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P aeruginosa are ______________ pathogens |
extracellular - ability to grow based on resistance to phagocytosis by NEUTROPHILS |
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Ulcerative colitis |
ExoU/T are virulence factors Flagella/pili are adherence factors |
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Virtually all iron in serum is bound to _______________ |
Transferrin |
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Pseudomonas produces _____________ that compete with transferrin for iron |
Iron binding siderophores - Pyoverdin - Pyochelin |
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Iron limitation in pseudomonas causes production of _______________ |
siderophores exotoxin A proteases biosurfactant Rhamnolipid Damage tissues to make iron more available |
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When phosphate is limited, _____________ is produced |
phospholipase C |
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____________ are involved in preventing bacteremia and sepsis |
Neutrophils |
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CF theories for P aeruginosa |
Ion transport across the respiratory epithelium is abnormal because of a defective CFTR. Persistence of organism may be due to dehydration of respiratory secretions resulting in impaired mucociliary escalator P aeruginosa binds to asialo-GM1 which is increased on epithelial cells of CF patients P aeruginosa can activate and be internalized by CFTR expressing cells, which is defective in CF Alginate production is increased resulting in mucoid appearance - altered LPS with modified Lipid A and defective O antigen - fewer proteases and non-motile |
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Exotoxin A activity |
ADP ribosylation of elongation factor 2 required for protein synthesis |
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Elastase degrades |
elastin - zinc metalloprotease that degrades many other proteins |
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LasA |
serine protease that acts synergistically with elastase to degrade elastin |
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P aeruginosa has a type _______________ secretion system |
Type III - takes specific proteins from the cytosol of the bacteria and injects them into cytosol of host cell - avoids immune detection - host cell contact or low calcium |
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ExoS/T/U/Y are controlled by the transcription activator __________________ |
ExsA |
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ExoS and ExoT |
Similar to Lipid A - ADP ribosylates target proteins |
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ExoS causes ____________ of cells |
ROUNDING |
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ExoT interferes with ______________ of pseudomonas by epithelial cells and macrophages |
Internalization |
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ExoY has ____________ activity |
adenyl cyclase activity ExoY has "Yl" of adenyl |
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ExoU is a ______________________ |
Phospholipase causing lysis of host cells - more severe strains |
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P aeruginosa's ability to sense other bacteria in the environment |
quorum-sensing activity via the production of autoinducers - Two are derivatives of homoserine lactone - One is similar to quinolones |
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Quorom sensing activity |
W/ increasing cell density, autoinducers accumulate inside the bacteria - bind to transcription regulators and activate transcription of genes - allows p aeruginosa to accumulate in the host before immune response occurs - |
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P aeruginosa antibiotic resistance |
Limited permeability of outer membrane multi-drug resistance efflux pumps Acquire antibiotic resistant genes via transformation, transduction, and conjugation |
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P aeruginosa diagnosis |
Cultured and identified by clinical micro lab |
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Pseudomonas Tx |
Severity of infections depends on - state of host defenses - promptness and efficacy of treatment |
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High grade bacteremia in a neutropenic patient |
50-70% mortality rate |
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Effective antibiotics |
Combo treatments - extended spectrum B lactams - carbapenems - aminoglycosides - fluoroquinolones |
