Week 4 Antimicrobial Resistance Flashcards
According to the O’Neill AMR report, what are the major causes of death and the projected numbers for AMR-deaths? (IMPT)
- AMR (700,000 now, 10 mil by 2050)
- Cancer
- DM
- Diarrheal disease
- RTA
- Measles
- Cholera
- Tetanus
What are the factors affecting population health, that are not due to Abx? (IMPT)
- Clean water, sanitation, hygiene, vaccines
- More work, health, nutrition, wealth
- Less poverty and crowding
- More peace and absence of conflict
How can Abx resistance spread?
- Remain on meat in animals -> consumed and stay in human gut
- Fertiliser or water containing animal feces used to water food crops -> consumed and stay in human gut
- Spread within community
How does AMR come about?
- Antibiotics changes the normal body flora
~ Kills susceptible bacteria and allows resistant bacteria to take over - Overgrowth especially of candida and C difficile
How is AMR a threat to patient safety? (IMPT)
- ^ morbidity and mortality
- ^ LOS
- ^ Delays the appropriate Abx
- Eventually causes untreatable infections
According to the CDC, what germs are considered urgent threats?
- Acinetobacter (Carbapenem-resistant)
- Candida auris
- C difficile
- Enterobacteriaceae (Carbapenem-resistant)
- Neisseria gonorrhea
According to the CDC, what germs are considered serious threats?
- Campylobacter (Drug-resistant)
- Candida (Drug-resistant)
- Enterobacteriaceae (ESBL-producing)
- VRE
- MDR Pseudomonas aeruginosa
- Salmonella (Drug-resistant)
- Shigella (Drug-resistant)
- MRSA
-TB (Drug-resistant) - Strep penumoniae (Drug-resistant)
What is campylobacter associated with?
- Painful, bloody diarrhea
- Raw/undercooked poultry
- Cross-contamination of food
What kind of antibiotics are associated with ^ penicillin resistance?
Beta-lactam antibiotics
What is the empirical therapy for Strep pneumoniae meningitis?
- Ceftriaxone + vancomycin
- Unless lab report says bacteria is susceptible to penicillin
Strep pneumonia RTI vs meningitis Abx
- Penicillins and ceftriaxone more reliable for RTI
- Does not penetrate BBB well so not well used for meningitis
Vaccine for streptococcus pneumoniae?
- Pneumococcal conjugate vaccine (PCV)
According to antibiograms, what drugs are recommended for Gram positive bacteria and what are not? (IMPT)
Recommended:
- Rifampicin
- Vancomycin
- Cotrimoxazole
Not:
- Cloxacillin (unless MSSA bacteria)
According to antibiograms, what drugs are recommended for Gram negative bacteria and what are not? (IMPT)
Recommended:
- Ertapenem
- Meropenem
- Tazobactam
- Amikacin
Not:
- Ciprofloxacin
- Cotrimoxazole
- Cefuroxime
What are some factors affecting choices for empirical therapy?
- Disease
- Type of cause
- Previous therapy
- Community-associated infections (CAI)
~ <48 hrs of admission
~ Bacteria is usually more susceptible
~ Often include px with multiple co-morbidities - Hospital-associated infections (HAI)
~ >48 hrs
~ Bacteria generally more resistant - Drug interactions
- Compliance
- Availability
What bacteria are susceptibility tests not carried out on?
- Legionella pneumophilia
- Chlamydia trachomatis
- Treponema pallidum
What lab tests are done to detect Abx resistance?
- Antimicrobial susceptibility test (AST)
- Minimum inhibitory concentration (MIC)
- Disc diffusion/ Kirby-Bauer method
- E test
How is MIC test done?
- Gold standard testing
- Serial dilution method to find out the lowest concentration with no visible growth
- Cultured overnight
How is E test for Abx resistance carried out?
- Strip with antibiotic gradient is put on a seeded plate to find out MIC
How is automated incubation for MIC done?
- Seeded onto small wells
- Same day results but results are approximated MIC instead
How is disc diffusion method done?
- Apply discs loaded with Abx and measure zones of inhibition where bacteria does not grow
Why may therapy fail despite “sensitive” being shown on the results? (IMPT)
- Presence of abscess or foreign materials
- Inadequate dose or duration
- Development of resistance
- 2nd infection
- Wrong diagnosis due to contamination or mislabeled sample
How to mitigate AMR?
- Infection control and prevention
- Education
- Ward level data
- Antimicrobial stewardship
Antimicrobial stewardship?
- Optimizing the use of antimicrobial agents to improve patient outcomes while minimizing the development of antimicrobial resistance and reducing the overall societal impact of antimicrobial overuse and misuse
- Control availability
- Set guidelines and carry out audits
- Educate
- Improve diagnostics
- Prevent infections (hygiene, vaccination, line care)
What are the common mechanisms of resistance?
- Inactivated antibiotic
- Altered target
- Decreased permeability
- Active efflux
- Bypass of target
- Overproduction of target
What are the major resistance mechanisms of B-lactam Abx (penicillin, cephalosporins, carbapenems)? (IMPT)
- B-lactamase production
~ Enzyme which destroys the antibiotic - Changes in the penicillin-binding proteins
~ Abx do not fit as well
~ Cell wall synthesis continues - Porin loss in cell membrane
~ Abx cannot enter the cell
What can be taken with B-lactams to counter AMR?
- B-lactamase inhibitors
- eg Co-amoxiclav (amoxicillin + clavulanic acid)
