Does Copper Silver Ionization (CSI) Kill Mycobacteria and NTM?
Copper-silver ionization (CSI) is a widely used method for controlling microbial growth in water systems, particularly against pathogens such as Legionella. However, its efficacy against Mycobacteria and Non-Tuberculous Mycobacteria (NTM) requires a more nuanced understanding, especially considering the distinct characteristics of these organisms. The first step in controlling these organisms is to have an ASSE 12080 certified consultant perform an independent risk assessment.
NTM, including species like Mycobacterium avium (M. avium), are gram-positive bacteria, which differentiates them from many common pathogens that are gram-negative. This distinction is crucial because the cell wall structures of gram-positive bacteria are different, affecting how they interact with antimicrobial agents. Copper and silver, known for their broad-spectrum antimicrobial properties, have shown varying degrees of effectiveness against both gram-positive and gram-negative organisms. It is believed that they tend to be more rapid and effective against gram-negative bacteria since they have positive charges, with silver, in particular, being somewhat less potent against gram-positive organisms. Despite this, both metals appear to impact gram-positive bacteria, albeit potentially at different rates and with differing efficacies.
The synergistic effect of copper and silver, when used together, can enhance their antimicrobial properties. This synergy has been well-documented in the control of Legionella, a gram-negative bacterium. It’s reasonable to hypothesize that a similar synergistic effect might exist against NTM, although specific data on this are scarce, and the use of CSI for NTM should be considered carefully.
The challenge with NTM is their inherent resilience. Compared to other pathogens, NTMs, including species like M. avium, can show significant resistance to various disinfectants, including conventional oxidants like chlorine, chlorine dioxide, and monochloramine. This resistance is a concern in clinical and public health settings such as hospitals and skilled nursing facilities because NTMs are among the possible opportunistic waterborne pathogens.
A laboratory study that investigated the effect of CSI on NTM may provide some insights. While CSI has been effective against Legionella, it also suggests potential efficacy against NTM. The study indicates that M. avium is susceptible to the bactericidal effects of copper and silver ions. However, it is crucial to note that M. avium shows a higher resistance compared to Legionella, requiring significantly longer exposure times to achieve comparable killing effects. This finding is important as it implies that while CSI might be effective against NTM, the application parameters such as ion concentration and exposure duration might need to be adjusted significantly compared to its use against Legionella.
Therefore, in the context of hospital and healthcare hot water systems, which are critical environments for controlling pathogens, the potential of CSI to control both Legionella and NTM appears to be promising. Although M. avium and other NTM require much longer exposure to copper and silver ions, the data suggest that appropriately managed CSI systems might still mitigate the risk posed by these pathogens. It is a critical part of any water management program to test for NTM and Mycobacteria on a regular basis.
Given this information, copper-silver ionization may hold potential as a strategy against NTM, including M. avium, in water systems. However, its application needs careful consideration of the unique resistance properties of these organisms, particularly the need for extended exposure times compared to other pathogens like Legionella. This understanding underscores the importance of tailored approaches in antimicrobial strategies, especially in healthcare settings where NTM pose a significant risk. Moreover, the use of CSI in this context should be weighed against alternative remediation, mitigation, and prevention strategies. This is yet another reason why it is important to work with a truly independent waterborne pathogen consultant like Legionella Control Systems. Contact us to learn more.
