NTM (Nontuberculous Mycobacteria) Testing
What are Nontuberculous Mycobacteria (NTM)?
Nontuberculous Mycobacteria (NTM) are a diverse group of bacteria found naturally in water, soil, and dust. While most people are exposed to them without any ill effects, they are recognised as “opportunistic pathogens.” This means they can cause serious lung infections (NTM-PD) in vulnerable individuals, making their presence in building water systems an emerging and significant public health concern.
Who is at Risk from NTM Infections?
NTM infections are not contagious between people but are acquired from the environment through the inhalation of contaminated water droplets or aerosols.
The risk is significantly higher for individuals with:
Pre-existing Lung Conditions:
Such as bronchiectasis, COPD, or cystic fibrosis.
Weakened Immune Systems:
Including hospital patients, the elderly, or those undergoing certain medical treatments.
For healthcare facilities and care homes, managing the risk of NTM in water systems is a critical part of protecting vulnerable patients.
Where are NTM Found in Water Systems?
NTM are hardy bacteria that are resistant to standard disinfection methods like chlorination.
They are hydrophobic and thrive by forming biofilms—slimy, protective layers on wet surfaces.
This makes them a persistent challenge in complex water systems.
Common risk areas include:
- Showerheads and taps (especially low-flow or aerosolizing outlets)
- Hot tubs and spa pools
- Heater-cooler units used in surgery
- Any area with stagnant water or complex, hard-to-clean pipework
- Ice machines
- Hydrotherapy and other medical equipment
- Aerators and filters
Our Laboratory Process
Step 1: Sample Delivered to Us
A water sample is delivered to our lab from our clients. This sample should be taken from a key risk point using sterile procedures to ensure sample integrity.
Step 2: Culture & Isolation
In our laboratory, the sample is cultured on specialist NTM-specific media, a process which can take several weeks due to the slow growth rate of these organisms.
Step 3: Notification & Reporting
Once growth is observed, a positive notification will be sent out prior to the final report at the end of the 4-week incubation. This provides the crucial data needed for your risk management plan.
Frequently Asked Questions
Q: Why is NTM considered an “emerging” risk?
A: While NTM have always existed, increased awareness and improved diagnostic methods have led to a growing recognition of the number of lung infections they cause, particularly in healthcare settings.
Q: Is NTM testing a legal requirement like Legionella testing?
A: Currently, there is no specific legal mandate for routine NTM testing in the UK in the same way as Legionella. However, for high-risk environments like hospitals, testing is considered best practice as part of a comprehensive Water Safety Plan to protect vulnerable patients.
Q: What happens if NTM is found in our water system?
A: A positive result should be reviewed by your Water Safety Group. It indicates that the conditions for NTM growth exist and that vulnerable individuals may be at risk. Actions may include enhanced flushing, physical cleaning of outlets, or considering point-of-use water filters in high-risk areas.