CSI - Javier Ratchett and HAI Flashcards
What type of settings can HAIs occur?
- Acute care hospitals
- Ambulatory surgical centres
- Dialysis facilities
- Outpatient care (GPs/Health Care Clinics)
- Long-term care facilities (nursing homes/rehabilitation facilities)
HAIs can basically occur in all healthcare settings.
It is an issue as patients with HAIs move between different healthcare facilities, leading for opportunities to potentially spread. Outpatient settings may have a limited capacity for infection control
What are the 2 main sources of HAIs?
Preventing HAIs means focussing on 2 sources of HAIs, CLABSI and MRSA.
- CLABSI central line-associated bloodstream infection: an HAI that occurs when bacteria and pathogen enter the blood steam through the central line (a long flexible tube placed in a large vein that empties out near the heart). This type of infections results in thousands of deaths every year
- MRSA methicillin-resistant staphylococcus aureus: a type of bacteria that is resistant to many antibiotics. Depending on the portal of entry, it can cause life-threatening bloodstream infections, pneumonia and surgical site infections
What are some common types of HAIs?
- catheter-associated UTIs
- surgical site infections
- bloodstream infections
- pneumonia
- clostridium difficile
What are the 5 times you should especially wash your hands???
- before touching a patient
- before a clean/aseptic procedure
- after body fluid exposure/risk
- after touching a patient
- after touching a patient’s surroundings
what are types of carriers?
Convalescent carriers recovered from illness but can transmit the pathogens to others
Chronic carriers continue to be able to transmit the illness (Hep B)
Incubatory illness can transmit during incubation period before clinical illnesses begin
Zoonosis infectious disease that is transmissible from animals to humans
What are the impact of HAIs?
- Hospital acquired infections have a massive knock-on effect on multiple people.
- It can mean the wider NHS (other patients, staff), healthcare workers, the patient and their family, as well as other visitors are at risk
- Prevention efforts must then expand across the continuum of care, so resistant infections are best addressed through coordinated action in an area
the mechanism/process of antibiotic resistance
- Antibiotic resistance means the causative agent (bacteria) is resistant and no longer sensitive to the antibiotic
- Using broad-spectrum antibiotics, prescribing too low a dose, prophylaxis, over-prescription, patients not finishing the course are pressures which leads to the development of antibiotic resistance as bacteria develop mechanisms of how to adapt. Due to natural selection, the bacteria that survive are able to confer the genes of antibiotic resistance to their offpsring
- There are 5 pathways/mechanisms
how can bacteria spread genes of resistance? (mobile genetic elements)
- Plamids
- Transposons (moleculear shuttles integrating plasmid into chromosomal DNA)
- Naked DNA (DNA from dead bacteria is released into the environment, so other bacteria can incorporate its DNA)
- Bacteriophages (viruses that attack bacteria and carry DNA
what is the mechanism/process of spreading antibiotic resistant genes?
- Transduction (spreading resistance genes via bacteriophages)
- Conjugation (resistance genes can be transferred when they connect via pilus)
- Transformation (extra cellular resistance genes released from nearby live or dead germs are picked up by another bacteria.
what is meant by antibiotic stewardship?
- Antibiotics are only needed for treating certain infections caused by bacteria, but even some bacterial infections can get better WITHOUT antibiotics
- Antibiotics are not needed for many sinus infections and some ear infections
- Use the shortest effective duration of antibiotic therapy optimise the treatment of the infection while minimising the risks of side effects from antibiotics/antibiotic resistance
- If sepsis is suspected, START ANTIBIOTICS IMMEDIATELY
- If you are asymptomatic, you shouldn’t be given antibiotics in most cases
what are the 5 ways antibiotics can become resistant to bacteria?
- decreased drug accumulation
- restrict antibiotic access
- altered metabolism profile
- inactivating the antibiotic
- altered target site
what is the chain of infection?
How infections are able to spread and cause disease. There are 6 steps in the chain.
- microrganisms
- reservoir
- portal of exit
- modes of transport
- portal of entry
- susceptible host
Gram positive bacteria
STAIN PURPLE due to thick peptidoglycan layer
Gram negative bacteria
Stains PINK due to additional plasma membrane
how does an altered target site lead to AB resistance?
Altered target site - Change in the structure of the site the antibiotic inhibits
- This can arise via acquisition of alternative gene or a gene that encodes a target modifying enzyme altering structural conformation of the protein that the antibiotic targets
how does an inactivating the AB lead to AB resistance?
- Enzymatic degradation or alteration rendering antibiotic ineffective
- Inactivation can also be enzyme independent
how does an altered metabolism profile?
- Bacteria switch to other pathways, reducing the requirements for the target of the antibiotic
- Increased production of enzyme substrate can out-compete the antibiotic inhibitor
how does restricting AB access lead to AB resistance?
- Changing the entryways or limiting the number of entryways (eg, gram-negative bacteria have an outer membrane protecting them from their environment)
how does decreased drug accumlation of the antibiotic affect AB resistance?
- Reduced penetration of antibiotic into bacterial cell/ or increased efflux of antibiotic out of the cell (drug doesn’t reach concentration required to be effective)
- Selectively pumps by recognising and ejecting toxic chemicals
