ABSTRACT
Background Facemasks (FM), due to the Covid-19 pandemic, are extensively used and often worn beyond the recommended time. This has led to questions about the negative impact persistent contamination on FMs might have on public health. The study aims to assess the level of contamination reached in a small cohort of subjects after the recommended use (8 h) of FM. Methods This descriptive study was carried out between January and April 2022 on 17 people: 9 women and 8 men aged between 25-45 years. These two groups were divided into two micro-groups: women were selected according to their skincare habits (no skincare and skincare with cosmetics). In contrast, men were selected according to the length of their beards (thick or short beard). The FM was worn for 8 h in a controlled office setting, to avoid possible uncontrolled variables. Then, the FM was cut, placed in a tube with a recovery medium and centrifuged. The supernatant was removed and the pellet resuspended. Aliquots were plated on Petri plates and incubated for 48 h at 36 °C to count the Colony Forming Units (CFU). The statistical analysis was conducted using Stata software, performing the Wilcoxon matched-pairs and setting a significance level of p < 0.05. Results Women had higher FM contamination than men (= 4960 vs 3130 CFU/ml). Also, we found more colonies (= 18890 vs 3420 CFU/ml) in the FMs of women without skincare (p = 0.06), while among men, more colonies were reported for those with a thicker beard than for those with a shorter one (= 3300 vs 2960 CFU/ml). Conclusions Extensive FM use increases bacterial contamination exponentially. This could lead to changes in the facial microbiome, inducing skin conditions (such as allergic dermatitis and acne). Facial skin conditions are important public health issues for people wearing FMs daily. In addition, responsible handling of this equipment is essential to avoid the spread of SARS-CoV-2 through contact with these items, which can persist for many days. Key messages • Gender and physical characteristics may influence the level of contamination present on FFP2 face masks. • There is a need to increase community awareness on the proper handling of facemasks, prevent health problems for users, and limit the spread of infection to those around them.
ABSTRACT
Background Disinfection of contact surfaces has become common practice since the two-year Covid-19 pandemic. The transmission of microbial agents has long been the focus of public health and hygiene awareness campaigns. Indeed, the development of new disinfection technologies and approaches is attracting considerable interest in the scientific community. Mixed plastic powders with antimicrobial properties and silver ions that compromise the metabolism of microorganisms could reduce the contamination of the contact surfaces. We aimed to evaluate an inorganic antimicrobial agent (IAA) based on Ag ions and zeolite mixed in a resin. Methods This experimental study was carried out at the University of Siena, Italy. Different objects were produced in two versions: i) with an IAA mixed in plastic resin;ii) with a standard plastic mixture. To the eye, the two versions were indistinguishable and were randomly contaminated with the hands of several operators. After the hand contamination, T0, we sampled the objects using RODAC plates at T1 (1h) and T2 (6h), incubating at 36 °C for 48 hours. Comparisons of the biocidal effect were made at T1 and T2. Statistical analysis was carried out with Stata. Results The mean level of contamination of the objects made with standard plastic were, respectively 50 CFU (SD 36.5) at T1 and 20 CFU (SD 13.6) at T2. In comparison, the objects made with IAA resin showed a mean level of contamination of 10 CFU (SD 5.9) at T1 and 6 CFU (SD3.6) at T2. The objects made with IAA resin have shown a mean percentage reduction of contamination of 79.5% at T1 and 78.3% at T2. Conclusions IAA resin reduced contamination on objects that came into contact with hands. Antimicrobial plastic blends, are a valuable aid in counteracting the spread of infection related to contact with surfaces and fomites. The public health system could support and raise awareness for using these innovative materials for everyday applications and in healthcare facilities. Key messages • Inorganic antimicrobial agent based on Ag ions and Zeolite mixed in a resin are efficient in reducing the contamination on different items in a real-life context. • Public health system have to support and sensitize to production with inorganic materials with proven antimicrobial properties.
ABSTRACT
Background In this historical period, it has become very important to live in healthy environments. By using everyday objects, cross-contamination is possible because of prolonged microbial persistence on surfaces. UV-C irradiation is an environmentally friendly method to disinfect objects as no harmful chemicals or heat are involved. This study aims to determine the virucidal activity, against SARS-CoV-2, of UV-C irradiation occurring in a designed UV device, ‘Purity Capsule'. Methods An experimental study was performed in September 2020. The ‘Purity capsule’ has an 11 W lamp (3.5W UV-C) positioned in the centre of the device. The lamp has a dome covered with a reflective, protective coating. Three metal carriers were placed at the maximum distance from the UV-C lamp in three different positions and tested at 30 and 60 seconds 3 times. The carriers were inoculated with 100 µL of SARS-CoV-2 viral suspension with a concentration of 106.5 TCID50 /mL. After treatment, laboratory procedures were used to transfer the treated virus from carriers to multiwell plates. The samples were compared with positive controls (not exposed to UV-C light) after incubation, at 37 °C in 5% COÕ · in a humidified atmosphere, for 3 days. The residual viral activity was tested by assessing the 50% infectious dose per tissue culture (TCID50%). Results Tests performed at 30 seconds of UV-C irradiation show an average viral reduction of 4.0 Log10 (99.99%). All three tests performed at 60 seconds reached the maximum measurable log10 viral reduction: 5.0 Log10 (99.999%). Conclusions The study assessed the effectiveness of the device in significantly reducing the viral load on all carriers regardless exposure time and distance from the UV-C light source, with no impact on the level of environmental pollution. Key messages • UV-C light has the property of inactivating viral growth;its physical approach is considered a good compromise between cost and effectiveness. • The device was effective in disinfecting all small everyday objects tested.
ABSTRACT
Background COVID19 outbreak highlighted air disinfection's importance. All bacteria and viruses tested to date (including various coronaviruses) respond to UV-C disinfection. This study aims to assess the effectiveness of an UVC disinfection system for air in a real working context. Methods This descriptive study was carried out in November 2020 in an office of the Department of Molecular and Developmental Medicine at the University of Siena. The disinfecting air system, Cleaning Air T12, produced by Italia Iso Group, has 12 lamps of 6.9 Watt of UVC/each, two inlet grills in its bottom and 2 outlet grills in the superior part. The volume of air that the system treat is of 210m3/h. The experiments were run over several days during the activities of 3-5 subjects working for several hours. Real time microbial air samplings were run during the tests switching the system ON and OFF. To verify microbial time variation, initial samplings (phase 1) had the system OFF, then ON (phase 2) and finally OFF again (phase 3). Petri dishes were incubated at 36 and 22 C°. Statistical analysis was executed with Stata 16. Significance level was set at p < 0.05. Results The longest test highlighted that during phase 2, after 8 minutes from the end of phase 1, the system acted significantly (p = 0.001) on the reduction of environmental contamination up to a mean of 70 (95% C.I. 64 - 77) CFU/500 liters (about 70% at 22 °C) and 50% at 36 °C. In phase 3 the mean values became 171 (144 - 198) CFU/500 liters at 22C° and 259 (228-291) at 36 °C. Conclusions The system was able to significantly reduce the environmental contamination in real time. The experimental tests show how, as soon as the device is turned OFF after at least half an hour of operation, air healthiness drops dramatically within 10 minutes, bringing the levels of microbial contamination (induced by the presence of the operators in the room) to levels even higher than 150%. Key messages In order to convey a correct and truthful message about the disinfection capabilities of an air purification system, testing the device under real operating would be necessary. Testing the device under real operating conditions, with and without the presence of people in controlled environments, would be necessary before the final product is placed on the market.
ABSTRACT
Background Surface sanitation is one of the key points to reduce the risk of transmission both in healthcare and other public spaces. UV-C is already used in hospital and laboratory's disinfection procedure furthermore some recent studies show effectiveness on SARS-CoV-2. UV-C may be generated by Lamps and Light Emitting Diode, but novel sources are emerging. The aim of the study was to test a device having UV chips for inactivating SARS-CoV2. Methods The descriptive study was conducted in the period between June and July 2019, in laboratories of the University of Siena and of the scientific park of Toscana life sciences. The device, shaped in a rectangular box, contained six UV chips (10 mW each, with a peak at 264nm nm ranging from 260 to 350 nm) placed in the bottom. Central and short side long positions were tested expecting different dose levels. Each experiment was conducted in triplicate, with and without the device lid, at 3, 6 and 10 minutes. All repetitions were tested for SARS-CoV-2 having a virus suspension of 10
ABSTRACT
The coronavirus SARS-CoV-2 pandemic has become a global health burden. Surface sanitation is one of the key points to reduce the risk of transmission both in healthcare and other public spaces. UVC light is already used in hospital and laboratory infection control, and some recent studies have shown its effectiveness on SARS-CoV-2. An innovative UV chip technology, described in Part I of this study, has recently appeared able to overcome the limits of old lamps and is proposed as a valid alternative to LEDs. This study was designed to test the virucidal activity on SARS-CoV-2 of a device based on the new UV chip technology. Via an initial concentration of virus suspension of 10<sup>7.2</sup> TCID<sub>50</sub>/mL, the tests revealed a viral charge reduction of more than 99.9% after 3 min;the maximum detectable attenuation value of Log<sub>10</sub> = 5.7 was measured at 10 min of UV exposure.