Hospital Acquired Infection Flashcards
HAI
An infection patients get while receiving treatment for medical or surgical conditions which can be prevented
Central line associated blood stream infections
A serious HAI that occurs when germs eg bacteria enter the blood through central line
MRSA
A type of bacteria resistant to many commonly used antibiotics that causes life threatening bloodstream infections,pneumonia and surgical site Infections
5 commmon types of HAI
Catheter associated HAI
Surgical site infections
Bloodstream infection
Pneumonia
Clostridium difficile
Transmission
Transmission occurs when the agent leaves its RESERVOIR or host through a PORTAL OF EXIT and
is conveyed by some MODE OF TRANSMISSION and enters through an appropriate PORTAL OF
ENTRY to infect a SUSCEPTIBLE HOST. This is known as the CHAIN OF INFECTION.
Indirect transmission
Transfer of an infectious agent from a reservoir to host by
Suspended air particles
Inanimate objects
Vectors
Portal of entry
Open wounds
Catheters
Cannulas
Vomit
Diarrhea
Controlling measures
Antibiotic
Bed nets
Masks
Long pants
Vaccination
Prophylactic use of antimalarial drugs
5 moments of hand hygiene
Before touching a patient
Before a clean procedure
After bodily fluid exposure
After touching a patient
After touching a patients surroundings
Gram positive bacteria
Stain purple
Gram positive bacteria
Stain purple
Thick layer of peptidoglycan
Single membrane
Gram negative
Stain red or pink
Thin layer of peptidoglycan
Double layer
Infection test results
High c reactive protein
High wbc
Septic shocked
Hypotension
Tachycardia
Tachypnoea (increased respiratory rate)
Altered target site
Acquired aquisitiom of alternative gene which alters structural conformation of protein
Eg MRSA encodes an alternative penicillin binding protein,this has a lower affinity for b lactams
Strep pneumonia resistance occurs via erm gene which methylates antibiotic target site
Inactivation of antibiotic
Enzyme degradation
Eg beta lactamase and chloramphenicol acetyl transferase
Altered metabolism
Increased production of enzyme substrate can out compete antibiotic inhibitor
Bacteria may switch to other metabolic pathways
Decreases drug accumulation
Reduced penetration of antibiotic or increased efflux
B lactam mechanism
B lactam antibiotics contain a beta lactam ring and works by inhibiting cell wall biosynthesis
Interferes with synthesis of peptidoglycan by mimicking components of cell wall
Enzymes in bacteria mistaken b lactam antibiotic for cell wall precursor and bind it so B lactam bind to active site and deactivate it stopping growth
B lactamases
Enzymes produced by bacteria to provide resistance to B lactam antibiotics
Co amoxiclav
Contains amoxicillin and clavulanic acid
Amoxicillin is a b lactam antibiotic
Clavulanic acid is a b lactamase inhibitor so prevents breakdown of amoxicillin
Clavulanic acid binds to beta lactamases so amoxicillin can bind to serine on d alanyl d amine transpeptidase and prevent peptidoglycan cross link formation
Sources of antibiotic resistance genes
Plasmids-extra chromosomal dna carry multiple resistant genes ,selection for one maintains resistance for all
Transposons-molecular shuttles that integrate plasmids into chromosomal dna allowing transfer of genes from plasmid to chromosome
Naked dna-dna from dead bacteria released into environment so bacteria in close proximity can incorporate into own dna
Bacteriophages-viruses that attack bacteria and can carry dna from germ to germ
Transduction conjugation and transformation
Transformation is uptake of Extracellular dna
Transduction is phage mediated dna transfer
Conjugation is pilus mediated dna transfer
