Antimicrobial products in the home: the evolving problem of antibiotic resistance Flashcards
What is a biocide?
Synthetic or semi-synthetic molecules that, above certain concentrations and under defined conditions, will kill living cells within specific time intervals
What are sterilants?
Biocides that destroy all forms of microbial life
What are disinfectants?
Biocides that eliminate infectious pathogenic bacteria
What are sanitizers?
Biocides that reduce microbial contaminants
What are fungicides?
Biocides that destroy fungi on inanimate surfaces that are pathogenic to humans and animals
What are examples of mechanical devices used to control microrganisms?
- indoor air
- electronic air cleaners
- ion generators
- mechanical filters
- pleated filters
- activated charcoal impregnated filters
- ozone generators
- UV light
- thermal mechanisms
What are alcohols mechanism of action?
Denaturation of proteins
What do alcohols have less activity against?
- bacterial spores
- some non-enveloped (non-lipophilic) viruses e.g. hepatitis A
- protozoan oocytes
What non-enveloped viruses do alcohol-based hand rubs have activity against?
- rotavirus
- adenovirus
- rhinovirus
- hepatitis A
- poliovirus
What is chlorhexidine’s mechanism of action?
Disruption of cytoplasmic membranes with subsequent precipitation of cellular material
What agents do chlorhexidine have activity against?
- Gram positive
2. Enveloped viruses e.g. HSV, HIV, CMV, influenza, RSV
What agents does chlorhexidine have limited or no activity against?
- Gram negative bacteria
- Fungi
- Mycobacterium tuberculosis
- Spirocetes
- Non-enveloped viruses e.g. rotavrius, adenovirus, and enterovirus
What is triclosan’s mechanism of action?
Enters bacterial cells and affects the cytoplasmic membrane and synthesis of RNA, fatty acids, and proteins
What is triclosan’s activity?
Antimicrobial activity 0.2-2%, bacteriostatic
Gram positive > gram negative bacilli.
Reasonable activity against mycobacterium and Candida
Limited activity against filamentous fungi
What is a quaternary ammonium compounds mechanism of action?
Absorption onto the cytoplasmic membrane, with subsequent leakage of low molecular weight cytoplasmic components
What is the activity of quaternary ammonium compounds?
Mainly bacteriostatic and fungistatic
Gram positive > gram negative bacilli
Active against lipophilic viruses
Less active against mycobacteria and fungi
How effective are antimicrobial products in real life?
No evidence of real life effectiveness
What is dilute bleach recommended for?
Cleaning up significant spillage of bodily fluids
What is alcohol based solutions and gels recommended for?
Hand washing when soap and water are not available
What mechanisms exist for resistance in bacteria?
- Enzymatic inhibition
- Membrane impermeability
- Efflux pumps
- Alteration of the ribosomal target
- Alteration of the cell wall precursor target
- Alteration of target enzymes
- Overproduction of target enzymes
- Auxotrophs that bypass inhibited steps
What is the relationship between biocides and antibiotic resistance?
Potential impact requires further scrutiny as there is no definitive evidence but relationships have been seen with target gene mutations
What is the link between antibacterial products and allergies?
Inidividuals with allergies and eczema are more likely to have a Th1:Th2 imbalance with more Th2 activity. There maybe an association with excessive use of antibacterials in the home and development of allergies and asthma
What are recommendations for skin hygiene?
Mild, plain soaps are sufficient
Waterless hand hygiene gels are an altenrative
What are recommendations to prevent spread of respiratory tract infections?
- Frequent handwashing for 15-20s (may use either soap and water or alcohol based gel sanitizers)
- Not sharing cups, glasses, and utensils
- Cough and sneeze into tissue then immediately discard
- If no tissue is available cover the cough or sneeze and wash hands afterwards
