Case 3: Hospital Aquired Infection Flashcards
Describe 5 mechanism of antibiotic resistance?
- Reduce penetration
- Efflux pumps
- Change or destroy antibiotic with enzymes eg. Beta lactamase
- Bypass effect of antibiotic by changing metabolic pathways or by producing more substrate
- Change antibiotic’s target so that drug can no longer fit and do its job eg. enzyme with reduced affinity for beta-lactams
Describe the 5 moments of hand hygiene (when HCPs should wash their hands)
- Before touching patient
- Before aseptic procedure eg. changing catheter
- After body fluid exposure eg. blood samples, changing catheter
- After touching patient
- After touching surroundings eg. bedding
What are the five steps in a chain of infection?
Reservoir, portal of exit, modes of transmission, portal of entry, host
Describe what a reservoir is and give 3 examples
habitat where microorganism lives, grows and multiplies. eg. humans, animals, environment
what are the 3 types of human carriers?
asymptomatic, incubatory (transmit during incubation period), convalescent (chronic, after infection)
What is a portal of exit, give 3 examples
path by which pathogen leaves its host eg. respiratory tract, urine, conjunctivial secretions
Give 2 examples of direct and 3 examples of indirect transmission
Direct - direct contact ( skin-skin contact, kissing), droplet spread (sneezing, coughing)
Indirect - airborne eg. dust, vehicle borne eg. food, water, biological products, vector borne - either mechanical (fleas, ticks) or biological (eg. malaria where the pathogen undergoes maturation in intermediate host)
What is a portal of entry? Give 3 examples
Provides access to tissues where pathogen can multiply or toxin can act eg. respiratory tract, fecal-oral route, mucous membranes
List 5 common types of HAI
Catheter associated UTIs Surgical site infections blood stream infections pneumonia/ventilator induced pneumonia clostridium difficile ventilator site infections
Describe the mechanism of penicillin
The bacterial wall is made of peptidoglycan which forms chains linked through the action of DD-transpeptidase enzyme (penicillin binding protein).
Beta-lactam ring binds to PBP, inhibiting the cross linking activity and preventing new cell wall formation
The bacterial cell is now vulnerable to outside water & molecular pressures
Why does penicillin affect gram positive bacteria more than gram negative?
They have thicker cell walls and more peptidoglycan so more PBP activity. Gram -ve have thin walls with less peptidoglycan, surrounded by a lipopolysaccharide layer preventing antibiotic entry to the cell.
How does co-amoxiclav overcome one mechanism of penicillin resistance?
Clavunate is an irreversible inhibitor of beta lactamases produced by both gram positive and gram negative bacteria.
Prevents hydrolysis of amoxicillin, which allows an extension of the spectrum of amoxicillin to beta-lactamase producing bacteria
What are the best preventative measures to reduce the chances of HAI?
Hand hygiene, antibiotic stewardship, careful insertion maintenance and prompt removal of catheters, careful use of antibiotics
What is transduction?
Resistance genes transferred from one pathogen to another via phages
What is conjugation?
Resistance genes transferred between germs via a connection
