Final Review - Exam 3 Flashcards
(49 cards)
three main components of extracellular polymeric substances that bacteria produce
proteins, polysaccarides, extracellular DNA
steps in biofilm formation
- protein adsorption
- Bacterial adhesion
- bacterial proliferation
- biofilm maturation
- Detachment and dispersion
biofilm definiton
bacteria adherent to a surface (usually synthetic) that form and become embedded in a network of extracellular polymeric substances
why are biofilms hard to resolve
EPS shields the bacteria, protecting against host immunity cells like macrophages - it also becomes a transport barrier which hinders passage of antibiotics
high surface free energy promotes an ______ biofilm formation
increased -> more protein adsorption means higher biofilm formation
increased roughness promotes ______ biofilm formation
increased -> more surface area for protein adsorption
devices with high infection rate
urinary catheters, bioprostheic joints, cardiovascular devices
reasons for infection (biofilms)
1.breakdown in surgical sterility
2.transmission of bacteria through bloodstream from other site of infection
3. direct contact with adjacent infection (soft tissue, septic arthritis, osteomyelits)
DIAR (debridement, antibiotics, implant retention) process
- sample the local tissue to identify bacteria responsible for the infection
- lavage(clean) soft tissue around joint
- replace any modular prosthesis component that is not anchored to bone
- can implant in absorbable, antibiotic loaded calcium phosphate microparticles
- several weeks of high dose systemic broad-range antibiotics
EU vs US
EU is one stage, US is two stage
acute vs chronic PJI
4 week is cutoff (acute lower, chronic higher), acute is high virtulent bacteria and chronic is low virulent. acute can use DAIR but chronic requires complete replacement of prosthesis
three anti-microbial materials
- release of antiseptics
- silver - damages bacterial cell wall - used in catheters
- release of anti-microbial compounds,
orthopedic application
use PMMA which is loaded with antibiotics
undergoes radical polymerization in situ to provide mechanical fixation
dental application
called periodontitis, use of PLGA microspheres to deliver antibiotics
condensation polymerization
polymerization technique commonly used regarding PLA and PLGA, attaches two alcohols leaving an ester and water as a leaving group
degradation of PLGA
inverse of condensation polymerization
emulsion
explain/draw
does FDA approve biomaterials
no
biocompatiblity definiton
the ability of a material to perform with an appropriate host response in a specific application
3 key characteristics of foreign body response
chronic macrophage presence
formation of multi-nucleated foreign body cells
fibrous encapsulation
prolonged m1 macrophage activity causes
chronic inflammation
prolonged m2 macrophage activity causes
chronic fibrosis
3 functions of macrophages
phagocytosis
mmp production
growth factor production
what type of stimulis is required to differentiate m1 and m2 macrophages
growth factors
