X-MINING X-TALK Vol.8 【Part 2】 The Enduring Antibacterial Power of Copper That Remains Unchanged for Decades

My research has shown that the excellent antibacterial effects of copper last for a very long time.

For example, the 10-yen coin is one of the copper products most familiar to us. When we conducted antibacterial tests on 10-yen coins manufactured after 1952, each from different years, the results showed that their antibacterial effects were entirely unchanged, regardless of the coin.
Furthermore, when we examined the bactericidal activity (the property of inhibiting bacterial growth) of a copper plate roof that had developed patina (rust formed by the oxidation of copper), we found that it actually had stronger activity than a brand-new one.
Even as years pass and its appearance and color change, its properties do not diminish. This is another exceptional aspect of copper.

Ms. Ueno, how has your awareness changed after conducting experiments with Dr. Sasahara?

Learning about places where bacteria are prevalent has made me more cautious in my daily actions.
I now actively encourage my staff during morning meetings and other times to “Let’s keep it clean throughout the day,” emphasizing the importance of handwashing, among other practices.

No matter how excellent the medical care we provide, there’s always a risk of causing harm to patients through infections.

However, I’ve come to believe that there are infections we can prevent if we are careful, and it’s something we should always consider and strive to achieve.
However, I do feel there are challenges in ensuring continuous efforts among the staff.
When I show them the research data from the doctor, everyone is convinced and willingly adopts infection control measures.
But, especially in a university hospital where there is a high turnover of people, new staff members require fresh training. I believe it’s crucial not to neglect this continuous education.

Ms. Hatano, you are currently the head nurse in the dermatology ward. What initiatives have you undertaken regarding copper?

The skin functions as a barrier when healthy, but many patients who come to the dermatology ward lack this barrier function, creating an environment where infections can easily spread.
Given this background, since 2018, we have installed copper plates not only on door handles and medical PC cart handles but also on the floor of the ointment treatment room.
We have shared all the data from before and after the installation of copper plates with the staff, and the results are clear at a glance. Everyone acknowledges that “copper is indeed amazing,” and like Ms. Ueno, I became a fan of copper in an instant (laughs).

At Kitasato University Hospital, it seems you have also changed your cleaning methods following the introduction of copper products.

In conjunction with the transition to the new hospital, we prepared to establish a cleaning operation system that would facilitate the introduction of copper products.

Given that our hospital receives many outpatient visitors and is a very large facility, it inevitably becomes dirty.
However, we cannot justify moving patients around during their outpatient visits or hospital stays for cleaning purposes.
The challenge was how to maintain a certain level of cleanliness efficiently, quickly, and skillfully without causing inconvenience to both patients and staff on site.

Therefore, after consulting with Dr. Sasahara, we decided to clean using mops made of ultra-microfiber, a material with very fine fibers, and detergents containing hydrogen peroxide, which has a high disinfecting effect.
The dilution concentration of the detergent was determined after various verifications: 64 times for bathrooms and toilets, 128 times for clinical areas, and 256 times for other areas with less patient contact, adjusting meticulously for each location.
Additionally, because remaining moisture could lead to slip accidents within the hospital, we also made adjustments such as distinguishing between areas to be wiped with wet materials and those to be dried.

Now, it has been already 10 years since the new hospital was completed.
Going forward, we aim to tackle cleaning areas that are challenging to address in medical settings, such as the insides of pipes.

In recent years, regarding keywords such as antibacterial and antiviral, it’s unavoidable to mention the presence of the novel coronavirus, which has spread globally.

Since the dawn of humanity on Earth and the establishment of civilizations, contagious disease, or infectious diseases as they are referred to in modern terms, have always had a significant impact on human survival.
On the other hand, the fact that food stored in copper pots and vessels is less likely to spoil was known as far back as the Egyptian civilization, and even earlier in the Mesopotamian era.
There’s also historical evidence that copper was used in the water pipes and aqueducts of Greek and Roman urban civilizations, so it’s undeniable that copper has helped people live alongside infectious diseases.

Among these, the most recent challenge that has caused significant hardship for us Japanese has been the COVID-19 pandemic.

Kitasato University Hospital, as the name suggests, originated from the Kitasato Institute.
The Kitasato Institute was founded on the grand principle of supporting the foundation of people’s lives by creating vaccines and immune serums that prevent infections before they occur.

As an entity that has led preventive medicine in Japan, we have confronted the COVID-19 pandemic with a three-pillared approach of prevention, diagnosis, and treatment. Moving forward, we are considering how we might incorporate the antibacterial and antiviral properties of copper, which has supported human development, into a sustainable method of infection prevention for new forms of infectious diseases.