WEEK 5 - Alternative to Antibiotics Flashcards
List 4 alternatives to antibiotics
- Bioicdes
- Bacteriophage
- Larva Therapy
- Antimicrobial peptides
AIM:
- To inhibit / stop microbial growth
- Prevent infection
Biocides - definition and examples
DEFINITION:
- is the active chemical molecule that controls the growth or kils bacteria / microorganisms (in a biocidal product)
Examples:
- Disinfectants ~ used on inanimate objects
- Antiseptics - applied topically to prevent / treat infections
- e.g. povidone-iodine ~ stains skin, used before making incision
- Preservatives ~ added to products to inhbit micro-organism growth
- prevents contamination
- biocide is present before microorganism
OTHER INFO:
- Usually chemically synthesised
- Do NOT cause toxicity to humans, animals, environment
- AIM is to sterilse
Biocide class examples
- Phenols e.g. m-cresol
- Bis-phenols e.g. triclosan
- Organic / Inorganic acids e.g. propionic or lactic acid
- Biguanides e.g. chlorhexidine
- Aldehydes e.g. formaldehyde
- note e.g. is toxic = can NOT enter room disinfected using this gas unless all gas has been REMOVED - Alcohols e.g. ethanol (hand gels)
- Quaternary ammonium compounds e.g. benzalkonium chloride
How are biocides used in healthcare
8 Uses
- Surface Disinfection
- prevents cross-contamination between patients + HCP
- clean frequently touched surfaces, equipment, walls etc.
- e.g. alcohols, chlorine based compounds, quaternary ammonium - Hand hygiene
- ↓ spread of pathogens from HCP
- inc. hand sanitiser, surgical scrubs
- e.g. ethanol, isopropanol, chlorhexidine - Sterilisation of medical equipment
- remove microorganisms / spores from surgical tools
- e.g. hydrogen peroxide, ethylene oxide - Antiseptics for skin / wound care
- ↓ microbial load on skin
- for pre-operative skincare, wound cleaning
- e.g. povidone-iodine, chlorhexidine, hydrogen peroxide - Water treatments
- ensure clean water supply to prevent waterborne infections
- for drinking + washing water
- e.g. chlorine, UV radiation - Air disinfection
- ↓ no. of airborne pathogens
- for operating rooms, isolation wards
- e.g. UV lights, hydrogen peroxide vapour - Textile disinfection
- ensure hospital linen, bed sheets, staff uniforms are free from pathogens
- e.g. hydrogen peroxide - Antimicrobial coating
- provides long-term microbial resistance to surfaces
- used on hospital bed rails, door handles, high touched surfaces
- e.g. silver nanoparticles, copper ions, quat. ammonium
Explain the MoA for Biocides
Cell membrane disruption (MAJOR MoA)
- leads to inactivation / inhibition or death of microorganism
- NOT ALL bioicdes are membrantrophic
- Biocide disrupts microbial cell membrane or cell wall
- interacts with lipid bilayer (phospholipids) or membrane proteins - Compromises microbial cell membrane permeability
- i.e. structure + function is disrupted - Osmotic imbalance = leakage of cellular content
Bacteriophage - Structre INFO
2 types of bacteriophage
A virus that infects a bacterium / bacterial cell
STRUCTURE of Phage:
- Tail fibers which bind to bacterium surface receptors
- recepotrs are specific = specific phages can infect bacterium
- Injects genome into bacterium via phage central tail tube
- Tail tube and sheath gives specificity
LYTIC Phage:
- Causes LYSIS of bacterium
- Phage infects bacterium by injecting its genetic material into it
- Bacterial genome breaks down + phage genome replicates
- New phage burst bacterial host cell + infect other bacterium
- USED in therapy
LYSOGENIC (temperate) Phage:
- Does NOT cause LYSIS
- Phage injects its genetic material into bacterium
- Phage genome becomes integrated into bacteria genome = is rpelicated as bacterium duplicates
- Will produce bacterium containing phage material
- how resistance + virulence factors can transfer
How are bacteriophage used in healthcare
4 Uses
- Treat Antibioitc Resistant Infections
- MoA: phage infect bacterium, injecting genome + replicating in bacteria until bacterium lyses = new phages released
- Pathogens: MRSA, MDR pathogens, E.coli, Staph. aureus
- Use: wounds, pneumonia, sepsis - Wound care and Infections
- ↓ microbial load in chronic wounds + surgical site infections
- MoA: phages applied topically to selectively target + kill bacteria
- e.g. apply phage-based dressings or gels - Bacteria caused GI Infections
- MoA: orally taken, phage target harmful bacteria in gut (+ preserve beneifcial micrbiota)
- Pathogens: C.diff, salmonella - Antibiotic-resistant Respiratory Infections
- MoA: inhale phage preparation, targets bacterium in lungs
- Pathogens: pneumonia
Explain what ‘personalised phage therapy’ is and what the beneifts are
Personalised phage therapy:
- Targeted therapy personalised to specific bacteria causing patient’s infection
- Phage is selected / engineered to target the specific bacteria
- may need to isolate bacteria to identify correct phage
ADVANTAGES:
- High specificity
- phage target specific bacteria without harming commensal microbiota
- Low resistance development
- bacteria develope resistance to phages slower than to antibioitcs
- Penetrate + disrupt bacterial biofilm
- Are biodegradable = environmentally friendly (break down easily)
What are the challenges with phage therapy
- Not widely approved = frameworks still evolving
- Host immune response may clear phage before they fully eradicate infection
- More research required for their production and stability
- Economic problem (companies may not see much profit in developing them)
Larval Therapy (MRSA) - INFO
a.k.a. Maggot therapy
Use of live, disinfected larvae / maggots to clean + promote healing in chronic wounds
- larvae is produced in sterile environment
Larvae is highly selective i.e. only eat necrotic tissue not live, healthy tissue
USE:
- For antibiotic resistant bacteria found in chronic wounds
Necrotic - dead / infected tissue
What is the MoA of Larval therapy
inc. antimicrobial and healing actions
- Larvae are applied directly to wound
- Larvae feed on dead tissue
- secrete enzymes that break down infected tissue into a form they can inject
- i.e. biosurgical debridement - Removal of dead tissue speeds up healing process
- i.e. wound cleaning process
Antimicrobial Action
- Larvae degrade + disrupt bacterial biofilm
- Larvae produce secretions that are antimicrobial
- secretions fight infection
- secretions have broad-spectrum antibacterial properties
- ↓ need for systemic antibiotics
Promote Healing
- Larvae secretions contain growth promoting factors
- stimulates wound healing
- encourages granulation / new tissue
- Larvae movement in wound stimulates blood circulation
- ↑ tissue O2 = accelrates healing
What is biofilm
Biofilm - produced by bacteria to protect it against antibiotics + immune system
Can be BROKEN BY:
- Bacteriphages
- Larvae therapy
Break down allows immune system + other tretaments to eliminate bacteria
- They are typically resistant to antibiotics
- Form in: chronic wounds
How is larval therapy used in healthcare
Used to treat wounds difficult to heal, infected or dead tissue
Examples:
- Chronic ulcers
- e.g. diabetic ulcers, pressure sores
- Necrotic wounds
- Post-surgical wounds
- Burns
- Amputation sites
What are the benefits of larval therapy
5 benefits
- Selective debridement
- only consume dead, infected tissue
- clean wounds without harming healthy tissue
- Have antimicrobial action
- Reduce the need for systemic antibiotics
- Promote healing
- Minimally invasive
- therapy doesn’t require surgery
- non-invasive
What are the challeneges and contraindications related to larval therapy
CHALLENGES:
- Patient perception and acceptance
- some patients may be uncomfortable with the idea of live maggots
- Cost
- cheaper than surgery but can still be expensive
- Wound care expertise
- larvae therapy has to be administered by specialist in wound care
- requires monitoring + management
CONTRAINDICATIONS:
May not be appropriate for:
- patients with allergies to larvae, componets of their secretions etc.
- patients with very sensitive skin
- wounds healing well with other methods
Antimicrobial Peptides (AMPs) - INFO
Inc. definition, challenges
Chains of naturally occuring amino acids that have broad-spectrum antimicrobial properties
- Have activity agianst bacteria, viruses, fungi and parasites
- Always have AMPs present in and on our bodies
CHALLENGES:
- Ensuring stability
- Minimise toxicity
- Avoid resistance development
How is antimicropbial peptides used in healathcare
9 Uses
- Topical wound treatments
- inc. AMP dressings and gels
- promotes healing + prevents infection
- Medical device coating
- ↓ infection risk, prevent bacterial adhesion + biofilm fomration
- apply to cathers + impants
- Systemic antimicrobial therapy
- AMPs used to treat systemic infections, esp. MDR bacteria
- Anticancer therapy
- some AMPs target cancer cells
- Dental and oral health
- help prevent dental caries + oral infections
- Antiviral therapies
- effective against viruses like influenza, HIV, coronaviruses
- Immunomodulation
- can control inflammation + enhance immune responses
- useful in autoimmune diseases + sepsis
- Biofilm disruption
- AMPs prevent / break down biofilms
- Synergistic use with antibiotics
- can enhance effectiveness of antibiotics against resistant bacteria
What is the pharmacists’ role in antibiotic alternatives
- Educate + counsel patients on non-antibiotic treatment options
- Promote vaccines
- Prescribe / recommend alternative therapies
- Antimicrobial stewardship
- Create personalised alternative therapies
- Contribute to development of new antimicrobial agents
- Resistance monitoring (promote alternatives + adjust treatments as needed)
- Advocate for changes to use non-antibiotic approaches
