Innovative Cleaning Strategies: Lessons from Italy's Subway System
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Understanding the Challenge
In mid-2021, as we began to see progress in managing the COVID-19 pandemic, with vaccines getting approval from the U.S. Food and Drug Administration (FDA) by late August, efforts to maintain cleanliness in public transport systems continued. In Italy, for instance, health officials took proactive measures by disinfecting subway cars with chemical solutions aimed at eliminating bacteria and viruses to ensure passenger safety.
This situation sparked an intriguing research idea: instead of merely eradicating bacteria, what if we introduced beneficial ones? Could the introduction of specific bacteria enhance subway cleanliness?
This concept may seem unconventional, yet it mirrors practices in other domains, such as maintaining a healthy lawn to suppress weeds or fostering a robust gut microbiome to prevent harmful bacteria like Salmonella and Listeria from thriving.
Research Experiment in Milan
In Milan, researchers embarked on this exploratory journey by developing a probiotic blend capable of thriving in the subway environment. They aimed to see if this added bacteria could help prevent the resurgence of harmful pathogens.
Choosing the Right Probiotic
To establish a protective barrier on subway cars, the scientists selected a specific genus of bacteria known as Bacillus. This choice was strategic, as Bacillus can form resilient spores that endure harsh conditions, such as cleaning agents. When conditions improve, these spores can reactivate and proliferate.
Bacillus is also known for producing powerful antibiotic substances that can inhibit competing bacteria. Additionally, this genus can break down biofilms, the slimy layers that bacteria often form on surfaces.
The researchers conducted a comparative analysis on two subway trains:
- The first underwent standard chemical cleaning with agents like ethanol, ammonium, and chlorine.
- The second train received partial chemical treatment, substituting chlorine with the application of Bacillus spores.
Bacterial Levels and Findings
Throughout the study, samples were collected biweekly, including swabs from floors, seats, handrails, doors, and air filters.
The findings revealed that subway trains harbor significant bacterial populations, albeit unevenly distributed. The floors and air contained the highest bacterial concentrations, while doors and handles exhibited lower levels, potentially due to their material composition.
Key Insight: Wearing a mask while on the subway is more beneficial than obsessively sanitizing hands after touching handrails or doors.
Next, consider the data presented in Figure 3 from their study:
The graphs demonstrate that both trains started with high bacterial counts. Over time, the chemically cleaned train (CTR) saw a slight decline in bacterial levels, whereas the probiotic-treated train (PCHS) experienced a substantial reduction.
Were these bacteria replaced by the introduced probiotics?
Figure 4 suggests a positive correlation, as levels of Bacillus consistently increased on surfaces. Air samples showed variability, likely due to the transient nature of bacteria in the air.
Impact on COVID-19 Detection
The researchers conducted this study amid the COVID pandemic, which facilitated funding and heightened public health interest in subway sanitation. They identified 21 samples that tested positive for COVID, with a higher incidence in the chemically cleaned train (13 samples) compared to the probiotic-treated train (5 samples). While this difference is noteworthy, the small sample sizes limit definitive conclusions regarding the probiotic's role in mitigating COVID spread.
Future of Probiotics in Cleaning
Implementing probiotics as a cleaning solution requires diligence. Since these live organisms cannot be stored indefinitely and need frequent application, they present unique challenges. Moreover, ensuring that the introduced bacteria are safe for public environments is crucial.
However, studies indicate that probiotics can effectively lower harmful bacteria levels in both hospital and subway settings, which is promising for public spaces that frequently welcome new visitors.
Interested in promoting this innovative approach? Consider discussing it with your local city council to advocate for cleaner, healthier public spaces.
This video, titled "What Doctors Learned from Swabbing Subways in Different Countries," provides insights into the research and findings related to subway cleanliness and public health.