Antimicrobial resistance Flashcards
AMR consequences on animal and public health
Increased patient mortality and morbidity
Risk of zoonotic transmission
AMR Economic consequences
More visits, laboratory test and therapies
Prolonged hospitalization (companion animals)
Reduced weight gain (food animals)
Loss of customers/reputation by veterinarians
Costs for hospital/farm decontamination
Costs for surveillance and intervention program
Microbiological definition AMR
Resistance is the property of bacterial strains to survive at higher antibiotic concentration compared with the wild type population (bacterial population that does not contain any resistance gene or mutation conferring resistance within the species)
The ability of microbes to grow in the presence of a drug that would normally kill them or limit their growth
Clinical definition AMR
Resistance is the bacterial ability to survive antimicrobial therapy and cause therapeutic failure
One health dimension of AMR
Spread between animals
Spread between animals and humans including via food
Spread between humans
Spread in environment, including via contaminated water and fertilizer
Different antimicrobial resistance strategies
To stop the antibiotic from reaching its target at high enough concentration
To modify or bypass the target that the antibiotic inhibits
To stop the antibiotic from reaching target
Efflux pumps
Decrease permeability of the membrane that surrounds the bacterial cell
Destroy the antibiotic: production of bacterial enzymes (B-lactamase)
Modify the antibiotic by adding different chemical groups to antibiotics
To modify/bypass the target
Camouflage the target
Express alternative proteins
Reprogram target: some bacteria can produce a different variant of a structure it needs
-vancomycin-resistant bacteria make a different cell wall compared to susceptible bacteria
Intrinsic resistance
Naturally acquired trait
Species or genus specific
Acquired resistance
By mutation in the existing DNA of the organism
By acquisition of new DNA via transformation, transduction or conjugation
Antibiotic selection
Bacteria that have acquired resistance keep passing it to other bacteria. At the same time, antimicrobials keep killing bacteria that have no resistance, increasing the share of resistant bacteria
Methicillin Resistant- Staphylococcus aureus, MRSA
Gram + skin commensal of many animals and humans (S. aureus)
Acquired resistance gene (mecA) encoding for new penicillin-binding proteins with low affinity to most B-lactams (penicillins and cephalosporins)
Major role in nosocomial infections
-community-acquired MRSA
- Hospital-acquired MRSA
-Livestock-acquired MRSA
Methicillin Resistant- Staphylococcus pseudintermedius, MRSP
Gram + skin commensal of dogs
Acquired resistance gene (mecA), similar to MRSA
Approximately 70% of cases are skin and wound postsurgical infections acquired in the clinic (nosocomial infections)
Some MRSP strains are multi-drug resistant bacteria (MDR) and may be resistant to all antibiotics licensed for veterinary use
Extended Spectrum Beta Lactamase producing enterobacteriaceae, ESBL
Gram - bacteria producing an enzyme that can hydrolyze/inactivate most B-lactams, except Carbapenems
Risk of foodborne transmission is higher for ESBL-producing E coli
-gut commensal
-may transfer from animals to humans via consumption of meat
-Upon ingestion, may colonize the gut and transfer ESBL-encoding plasmids to resident e. coli
Antimicrobial dilemma
Antimicrobials are essential in the cure of infectious diseases in humans and animals
Antibiotic selection leads to reduced efficacy over time
AMR cannot be eradicated but only controlled through rational animicrobial use
Critical questions for implementing rational antimicrobial use in vet practice
Antimicrobial? -reducing overall antimicrobial consumption Culture? -improving use of diagnostic testing Choice of drug -prudent use of second line, critically important antimicrobials Which drug dosage -optimizing dosage regimes
Reduce overall antimicrobial consumption
Disease prevention: hygiene, management, vaccination
Avoid unnecessary, routine prophylaxis
- growth promotion
- clean sterile surgery doesnt always need post-operative prophylaxis
Avoid unnecessary therapy
- viral infections (upper respiratory tract infections)
- self-limiting infections (acute diarrhea)
- disease conditions which require solely topical products (superficial pyoderma and wounds)
Improvising use of diagnostic testing
Maximize use of cytology to guide antimicrobial choice for relevant disease conditions (UTI, otitis externa)
Increase the use of culture and susceptibility testing
Use a good diagnostic laboratory providing following services
-guidance for optimal specimen management (selection, collections, storage)
State of the art methods for identification and susceptibility testing
Implementation of transparent and ongoing quality assurance measures, preferably by accredited laboratories
Availability of skilled microbiologists for case-based report advice and data interpretation
To culture or not to culture
Bacterial culturing is amost never contraindicated Strongly recommended in following: -no response to therapy -previous antibiotic treatment -relapse or re-infection -immunocompromised patients -life-threatening infections -patients at risk of MDR carriage or infection -high prevalence of AMR -long treatment
Criteria for empiric therapy
Use of first choice drugs are defined by national or international animal and disease specific guidelines
Hold disease-specific antibiotics formularies indicating first choice drugs for each disease condition
National guidelines in general better than international ones
-take into account local patterns of antibiotic use
-local AMR trends
-Availability of antimicrobials on market
-National regulations on antimicrobial use
-Cultural differences
Prudent use of second line CIA
Minimize empiric use of CIAs, especially those that have broad-spectrum, are known to select for MDR bacteria and should be preserved for treatment of difficult infections
- 3rd and 4th generation cephalosporins
- Macrolides (limited to livestock and horses)
- Fluoroquinolones
Shoot high
Use the highest possible dose
For concentration-dependent drugs
To enhance therapeutic efficacy
To prevent selection of resistant mutants
Shoot regular
Administer the drug at regular intervals
For time-dependent drugs
To enhance therapeutic efficacy
Inform owner of the importance of compliance
Shoot fast
Treat the earliest and for the shortest time possible
Control of antimicrobial use
Legal interventions -limiting profit of prescriber -penalties for high use -ban and restriction Preventative vet med Antimicrobial stewardship
Control of AMR transmission
Farm biosecurity
Hospital infection control
Improved slaughterhouse hygiene
Education of consumers and owners
Antimicrobial stewardship
Antimicrobial Stewardship Programs are dedicated to improving antibiotic use, to optimize treatment and patient safety, and reduce adverse events associated with AMR
ASPs comprise education, clinical guidelines, pre-prescription approval, post-prescription review and computer-based decision support
Usually underdeveloped in vet clinics
Establishment of ASPs requires coordination by specialist, commitment by clinical staff, and collaboration with microbiology lab
Hospital infection control
Every vet clinic should have a formal infection control program, a written manual, and an infection control practitioner to coordinate program
Routine practices (hand hygiene, PPE, cleaning and disinfection)
Hospital surveillance of pathogens and AMR
