Antiseptics and disinfectants are chemical agents used to momentarily eliminate or inhibit the growth of microorganisms. These agents play a critical role in reducing healthcare-associated infections (HAI).
Antiseptics are used on living tissues: intact skin, broken skin, and mucous membranes.
Disinfectants are used on objects and surfaces: reusable medical devices, instruments, equipment, walls, floor, linen, etc.
The choice of antiseptics and disinfectants depends primarily on the type of activities performed in the health facility (i.e. primary care, surgical care, maternity care, etc.). In every facility, the infection prevention and control (IPC) practitioner or team should develop policies, guidance and training on the preparation, use, storage, renewal and disposal of antiseptics and disinfectants.
Adherence to manufacturer’s instructions is also crucial, particularly in relation to the following:
- Indications
- Compatibility with living tissue or objects and surfaces
- Concentration
- Dilution (if required)
- Volume to be applied and recommended contact time
- Safety measures to protect healthcare workers (HCW) during product preparation and handling, in particular, personal protective equipment (PPE) and adequate ventilation
- Recommended disposal method to minimise environmental impact
Inappropriate use of antiseptics and disinfectants can lead to:
- The spread of HAIs and increased use of antibiotics
- Local and systemic adverse effects in patients (skin irritation, tissue toxicity, systemic absorption, delayed wound healing, etc.)
- Short and long-term adverse effects in exposed HCW (skin, eye, airway irritation, etc.)
Effectiveness of antiseptics and disinfectants can be significantly reduced in the presence of dirt (soil, dust, debris, etc.) and organic matter (sputum, vomit, faeces, pus, blood and other body fluids). |
Core list of products
Antiseptics
- Povidone iodine and/or chlorhexidine
- Alcohol, e.g. ethanol (ethyl alcohol), isopropanol (isopropyl alcohol)
Disinfectants
- Detergent-disinfectant for medical devices
- Detergent-disinfectant for surfaces
- Chlorine-based compound, e.g. sodium dichloroisocyanurate
Other disinfectants may be needed according to the type of activities performed in the health facility and the level of disinfection required, e.g. glutaraldehyde (glutaral) for disinfection of endoscopy equipment.
Antiseptics
The most used agents include povidone-iodine, chlorhexidine and alcohol. While all three are effective against a broad spectrum of microorganisms, they differ in their onset and duration of action and in their indications and contraindications. Understanding these differences is essential for selecting the most appropriate antiseptic in each clinical situation.
Some antiseptics have persistent (residual) antimicrobial activity, i.e. they can continue to inhibit microbial growth after application, but the extent and duration of activity are not clearly defined.
Types of antiseptics
Povidone-iodine (iodophor)
Iodophors are formulations containing iodine combined with a solubilizing agent, such
as povidone. The povidone-iodine (PVI) complex provides a sustained release of free active iodine, resulting in persistent antimicrobial activity and reduced risk of systemic iodine absorption.
Despite this, PVI should be used with caution in patients at high risk of systemic iodine absorption, i.e. neonates, pregnant or breastfeeding women and patients with extensive wounds or thyroid dysfunction.
Chlorhexidine
Chlorhexidine (CHX) is an antiseptic with persistent antimicrobial activity. It is mostly found as the soluble salt chlorhexidine gluconate or digluconate.
CHX is available in aqueous or alcohol-based solutions. Alcohol-based solutions combine the rapid onset of action of alcohol and the persistent antimicrobial activity of CHX.
Contact with body cavities, brain, meninges, eye, and middle and inner ear should be avoided due to potential toxicity of CHX to these tissues. CHX alcohol-based solutions should not be used on mucous membranes or broken skin (wounds, burns, etc.).
Alcohol (e.g. ethanol, isopropanol)
The optimal concentration for alcohol antimicrobial activity is between 60 and 80% volume/volume (% v/v).
Alcohol solution or wipe is used on intact skin. It should not be used on mucous membranes or broken skin (wounds, burns, etc.). Due to its rapid onset of action and lack of persistent antimicrobial activity, it is mostly used for skin antisepsis before short procedures, such as injections or venepunctures. Not all products are intended to be used for skin antisepsis: some are specially formulated for surface disinfection or use as laboratory reagents. Always check manufacturer’s instructions for each product.
Alcohol-based handrubs (ABHR) are formulations used for HCW hand antisepsis. They contain alcohol combined with humectants and emollients to reduce skin irritation.
Observe safety instructions for storing, handling and applying any solution containing alcohol, given its flammable properties.
Use of antiseptics
| Indications | Products |
|---|---|
| Hand hygiene | |
Antiseptic handrubbing Surgical handrubbing (presurgical handrubbing) | Alcohol-based handrub (ABHR) |
| Surgical handscrubbing (presurgical handscrubbing, antiseptic handwashing) |
|
| Surgical skin preparation | |
| Surgical site preparation |
|
| Patient preoperative showering |
|
| Antiseptic cleansing of the surgical site |
|
| Antisepsis of skin and mucous membranes | |
| Antisepsis of intact skin |
|
| Antisepsis of mucous membranes | PVI 10% aqueous solution |
| Antisepsis of broken skin (wounds, burns) |
|
| Antiseptic cleansing of wounds |
|
| Oral antisepsis | CHX 0.2% mouthwash |
| Antisepsis of umbilical cord in neonates | CHX 7.1% dermal gel |
Notes:
- The time required for the antiseptic to achieve optimal antimicrobial activity on intact skin generally ranges from 30 seconds to 1 to 2 minutes, depending on the formulation. In practice, it is important to allow the antiseptic to dry completely on the skin before beginning the procedure. Typically, alcohol-based solutions dry faster than aqueous solutions.
- Not all ABHR can be used for surgical handrubbing. Check if the product is approved for this purpose. The technique of surgical handrubbing is different from that used for antiseptic handrubbing. For more information, refer to the document WHO Guidelines on Hand Hygiene in Health Care: a Summary (2009).
For more information, see antiseptic drug information sheets in the section Drugs for external use and antiseptics.
For skin antisepsis in neonates including surgical site preparation, follow national IPC guidelines or seek specialist advice.
Keep in mind that:
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Preparation of diluted antiseptic solutions
Some concentrated antiseptic solutions require dilution with water before use. Diluted solutions can be contaminated by pathogens during preparation, handling and storage.
To prevent contamination, the following precautions must be taken:
- Use clean water and clean containers for preparing diluted solutions.
- Label the bottle of diluted solutions: name and concentration of the product, date and time of preparation, and name of the operator.
- Prepare fresh solutions daily, in small volumes to avoid wastage or use of expired or contaminated solutions. Do not mix solutions prepared at different times. Discard unused diluted solutions after 24 hours.
- Clean, disinfect, and dry storage bottles thoroughly before refilling them with a fresh solution.
Disinfectants
Disinfectants are classified according to their spectrum of activity:
- Low-level disinfectants: bactericidal, fungicidal and virucidal (enveloped virus)
- Intermediate-level disinfectants: bactericidal, fungicidal, virucidal and mycobactericidal; may have some activity against bacterial spores
- High-level disinfectants: bactericidal, fungicidal, virucidal and mycobactericidal; more effective against bacterial spores
Type of disinfectants
Detergent-disinfectants
Detergent-disinfectants are formulations that combine a detergent (i.e. a cleaning agent) with one or more disinfectants for one-step cleaning and disinfection.
Detergent-disinfectants are low-level disinfectants, available as concentrated solutions that must always be diluted before use, as per manufacturer’s instructions.
Detergent-disinfectants for medical devices combine a detergent and two disinfectants, such as a quaternary ammonium compound (QAC) or laurylamine, and another agent such as CHX, to ensure broader antimicrobial activity. These products are preferred over chlorine-based compounds because they cause less damage to medical devices.
Detergent-disinfectants for surfaces usually combine a detergent and a single disinfectant (QAC or laurylamine). Their repeated use can leave a residue layer that can reduce the disinfectant antimicrobial activity and contribute to biofilm development. Periodic cleaning of surfaces with plain detergent and water is recommended to remove the residue build-up, following the frequency specified in the health facility IPC protocol.
Chlorine-based compounds
Chlorine-based compounds are intermediate-level disinfectants with no detergent properties. Their antimicrobial activity is rapidly reduced in the presence of organic matter. Cleaning of surfaces, medical devices and linen with plain detergent is imperative prior to disinfection with chlorine.
There are several products and formulations. Each one releases a specific amount of active chlorine. The amount of active chlorine released can be expressed in mg/litre, parts per million (ppm), percentage (%) or chlorometric degree (chl.): 10 000 mg/litre = 10 000 ppm = 1%; 1°chl. = approximately 0.3%.
Solid formulations (i.e. tablets, powder, granules) are preferred over liquid formulations (i.e. bleach). It is easier and safer - for a precise dosing - to use a solid formulation. They also have a longer shelf life, better stability and are easier to handle and store. Bleach should be reserved for domestic use only. Solid formulations must always be diluted with clean water, to create a chlorine solution in the concentration required.
Sodium dichloroisocyanurate (NaDCC), 1.67 g effervescent tablets releasing 1 g of active chlorine, is the formulation most used in healthcare facilities, but it can also be found in powder or granules.
Chlorine is corrosive to metal. Good quality stainless steel instruments are more resistant to corrosion. However, to avoid damaging instruments, do not exceed the required contact time and rinse thoroughly afterward.
For routine disinfection of healthcare facilities, a 0.1% chlorine solution is usually recommended. For use of chlorine during epidemics, refer to specialised guidelines (e.g. Management of a cholera epidemic, MSF).
Use of disinfectants
The level and frequency of disinfection of reusable medical devices and surfaces are based on the risk of pathogen transmission associated with their use.
Medical devices are classified into three categories:
- Non-critical: in contact with intact skin only and requiring low-level disinfection
- Semi-critical: in contact with mucous membranes or broken skin and requiring high-level disinfection
- Critical: in contact with sterile body parts and requiring sterilisation
This section of the guide only addresses the disinfection of non-critical devices (i.e. devices carrying low risk of infection compared to semi-critical and critical medical devices), which can be achieved with a detergent-disinfectant or, after cleaning, with a chlorine solution.
For surfaces, the risk of pathogen transmission depends on how often they are touched. High-touch surfaces (bedrails, doorknobs, taps, etc.) and floors require more frequent disinfection than low-touch surfaces (walls, etc.).
| Use | Product(s)/Method |
|---|---|
Reusable non-critical medical devices Trays, basins, kidney dishes, stethoscopes, blood pressure | Detergent-disinfectant solution Immerse the devices immediately after use in the solution to prevent organic matter from drying. Ensure a contact time of 15 minutes for full disinfection. Rinse with water and allow to dry. If the device cannot be immersed, use a cloth soaked with enough solution to ensure a contact time of 15 minutes for full disinfection. Rinse with a cloth soaked in water and allow to dry. OR 0.1% chlorine solution (one 1.67 g NaDCC tab/litre) Clean devices with a plain detergent. Rinse with water. Then immerse devices in 0.1% chlorine solution. Ensure a contact time of 15 minutes for full disinfection. Rinse with water, drain and dry with a clean, dry, lint free clot. |
Surfaces Walls, floors, benches, | Detergent-disinfectant solution Apply the solution without rinsing. Ensure a contact time OR 0.1% chlorine solution (one 1.67 g NaDCC tab/litre) Clean surfaces with a plain detergent. Rinse with water and allow to dry. Then apply the 0.1% chlorine solution without rinsing. For stainless steel surfaces, rinse with water after 15 minutes to prevent corrosion. |
Linen Bed sheets, blankets, towels, personal clothing, gowns, surgical drapes, etc. | 0.1% chlorine solution (one 1.67 g NaDCC tab/litre) Hand or machine wash with water and a laundry detergent and rinse. Then, immerse the linen in 0.1% chlorine solution. Ensure a contact time of 5 minutes. Rinse 3 times thoroughly to remove all chlorine. |
Notes:
- In case of spills of blood and/or other body fluids:
- Confine the spill and immediately wipe it up with disposable paper towels. Clean with plain detergent and water, then disinfect with an intermediate-level disinfectant (e.g. chlorine solution). Do not use a detergent-disinfectant in these cases.
- If there is a risk of sharp injury during cleaning/disinfection, the surface should first be decontaminated with chlorine solution, then cleaned and disinfected as above. Do not use chlorine directly on urine spills due to the risk of toxic chlorine gas release.
- Because of its rapid onset of action, alcohol alone or combined with CHX, is also used as
a disinfectant for vial stoppers of injectable drugs (except vaccine vials) and for some non-critical reusable medical devices that are not soiled by blood or other body fluids. Critical reusable medical devices (surgical instruments, etc.) cannot, under any circumstances, be “sterilised” by alcohol (whether by flaming, soaking or wiping).
Storage, preparation and handling of disinfectants
- Store disinfectants in airtight containers, protected from light, heat and humidity, in a well-ventilated room.
- Do not store NaDCC tablets near drugs and especially oral tablets, to prevent dispensing errors.
- Avoid inhaling vapours and dust when opening packaging. Wear PPE when preparing and handling disinfectants: gown, apron, gloves with long cuffs, goggles and splash resistant mask.
- Handle disinfectants with caution. Do not shake or expose them to high temperatures or flames.
- Use clean water and clean containers for preparing diluted solutions. Use only cool water for chlorine solutions.
- Use opaque plastic containers for preparation and storage of chlorine solutions.
- Ensure solid chlorine-based formulations are dissolved prior to use.
- Label the containers of diluted solutions: name and concentration of the product, date and time of preparation, and name of the operator.
- Prepare fresh solutions just before use or daily. Do not mix solutions prepared at different times. Discard solutions after use or after 24 hours if unused.
- Do not add any product to disinfectants solutions: chemical reactions may occur (inactivation of the disinfectant, release of toxic gas, etc.).
Clean and dry containers before refilling them with a fresh solution.