Study of synergistic disinfection by UVC and positive/negative air ions for aerosolized
 Escherichia coli
 ,
 Salmonella typhimurium
 , and
 Staphylococcus epidermidis
 in ventilation duct flow

Nunayon, Sunday S.; Zhang, Hui H.; Chan, Vincent; Kong, Richard Yuen Chong; Lai, Alvin C.K.

doi:10.1111/ina.12957

Cited by 12 publications

(8 citation statements)

References 46 publications

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“…alcaligenes had the highest susceptibility among the four tested bacteria for 222 and 254 nm UV wavelengths. This finding was also reported in previous measurements, , and it could be attributed to the thicker cell walls of gram-positive bacteria when compared with gram-negative bacteria. , …”

Section: Resultssupporting

confidence: 89%

“…It was observed that S. epidermidis gave the least susceptibility to UV irradiation, while P. alcaligenes had the highest susceptibility among the four tested bacteria for 222 and 254 nm UV wavelengths. This finding was also reported in previous measurements, 7,38 and it could be attributed to the thicker cell walls of gram-positive bacteria when compared with gram-negative bacteria. 39,40 Furthermore, it can be found that bacteriophage P22 was less susceptible to both 222 and 254 nm UV irradiation than the tested bacteria.…”

Section: Susceptibility Of Airborne Microorganismsmentioning

confidence: 92%

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Evaluation of Single-Pass Disinfection Performance of Far-UVC Light on Airborne Microorganisms in Duct Flows

Zhang

Lai

2022

Environ. Sci. Technol.

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Far-UVC irradiation (222 nm) is considered an emerging and sustainable solution for future infection and pandemic challenges. We examined the disinfection performance of a kryptonchloride lamp, with a quasi-monochromatic UVC peak at 222 nm, for inactivating airborne microorganisms in a full-scale ventilation duct system. Single-pass disinfection efficacy of far-UVC was determined and compared with that of a conventional mercury-type UVC (254 nm) lamp. Four bacteria, Escherichia coli (E. coli), Pseudomonas alcaligenes (P. alcaligenes), Serratia marcescens (S. marcescens), and Staphylococcus epidermidis (S. epidermidis), as well as bacteriophage P22, were tested under UV exposure with different velocities of duct flows. The data revealed that as the air velocity increased from 0.7 to 4 m/s, the far-UVC disinfection efficacies would decrease by 42, 47, 35, 39, and 33% for these five microorganisms, respectively. The inactivation rate constants to far-UVC light were 4.9, 7.5, 3.3, 6.3, and 3.0 cm 2 /mJ for aerosolized E. coli, P. alcaligenes, S. marcescens, S. epidermidis, and bacteriophage P22, respectively. Far-UVC irradiation showed a comparable disinfection ability on airborne microorganisms compared with the 254 nm UV irradiation. This first study of far-UVC in real duct applications provides a better understanding of the disinfection performance of this solution in bioaerosol inactivation. It offers a valuable database in the sizing and design of excimer lamps for novel portable air purifiers or induct disinfection units.

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Section: Resultssupporting

confidence: 89%

Section: Susceptibility Of Airborne Microorganismsmentioning

confidence: 92%

Evaluation of Single-Pass Disinfection Performance of Far-UVC Light on Airborne Microorganisms in Duct Flows

Zhang

Lai

2022

Environ. Sci. Technol.

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“…Negative ions gain hydrogen from surface molecules of pathogens due to electrostatic force. The elimination of hydrogen from or the disruption of the surface molecules of pathogens results in inactivation (Nunayon et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

“…Studies have shown that negative ions could disinfect a wide variety of aerosolized microorganisms, including Salmonella typhimurium (Nunayon et al, 2022), Staphylococcus epidermidis (Kim et al, 2011;Lee et al, 2014;Nunayon et al, 2022), Serratia marcescens , Escherichia coli (Huang et al, 2008;Park et al, 2009;Kim et al, 2011), Bacillus subtilis (Huang et al, 2008), Aspergillus niger, and Aspergillus versicolor (Huang et al, 2008). Escombe et al (2009) found that negative air ionization prevented most airborne Mycobacterium tuberculosis transmission detectable by guinea pig air sampling.…”

Section: Introductionmentioning

confidence: 99%

Aerosol Transmission of the Pandemic SARS-CoV-2 and Influenza A Virus Was Blocked by Negative Ions

Zhang

Chen

et al. 2022

Front. Cell. Infect. Microbiol.

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The pandemic of respiratory diseases, such as coronavirus disease 2019 (COVID-19) and influenza, has imposed significant public health and economic burdens on the world. Wearing masks is an effective way to cut off the spread of the respiratory virus. However, due to cultural differences and uncomfortable wearing experiences, not everyone is willing to wear masks; there is an urgent need to find alternatives to masks. In this study, we tested the disinfection effect of a portable ionizer on pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (strain V34) and influenza A virus (strain CA04). Negative ions significantly reduced the concentration of particulate matter in the air above and effectively disinfected viruses stuck to the solid plate at the level of both nucleic acid and virus titer. The disinfection efficiency was >99.8% after 1-h exposure. Moreover, negative ions effectively disinfected aerosolized viruses; the disinfection efficiency was more than 87.77% after purification for 10 min. Furthermore, negative ions had a significant protective effect on susceptible animals exposed to viral aerosols. When the negative ionizer was switched from off to on, the inhalation 50% infective dose (ID50) for golden hamsters challenged with SARS-CoV-2 rose from 9.878 median tissue culture infective dose (TCID50) [95% confidence interval (CI), 6.727–14.013 TCID50] to 43.891 TCID50 (95% CI, 29.31–76.983 TCID50), and the inhalation ID50 for guinea pigs challenged with influenza A virus rose from 6.696 TCID50 (95% CI, 3.251–9.601 TCID50) to 28.284 TCID50 (95% CI, 19.705–40.599 TCID50). In the experiment of transmission between susceptible animals, negative ions 100% inhibited the aerosol transmission of SARS-CoV-2 and influenza A virus. Finally, we tested the safety of negative ion exposure. Balb/c mice exposed to negative ions for 4 weeks showed no abnormalities in body weight, blood routine analysis, and lung pathology. Our study demonstrates that air ions can be used as a safe and effective means of blocking respiratory virus transmission and contribute to pandemic prevention and control.

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“…There are stationary strains. Disputes do not form (Nunayon et al, 2022). Escherichia coli is heat-resistant and can survive in the wild for several months (Lim et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Oral Administration of the Antibacterial Peptide MPX on Intestinal Inflammation of Mice in Experimental Infection with Escherichia Coli Strain O157: H7

Zhao

Fotina

Фотіна

et al. 2022

Scientific Horizons

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Escherichia coli is a gram-negative bacterium, an intestinal pathogen that can cause intestinal inflammation. Antimicrobial peptides are a class of small molecule peptides, which has good antibacterial activity against a variety of gram-positive and negative bacteria. In this regard, the authors aimed to study the effect of the antimicrobial peptide MPX, which was administered orally, on the intestinal wall of mice infected with the intestinal barrier function, which were infected with E. coli. Synthesis and purification of the antimicrobial peptide MPX (H-INWKGIAAMAKKLL-NH2) was performed by Jier Sheng Hua (Shanghai, China). Mass spectrometry and liquid chromatography (HPLC) were used for this purpose. Escherichia Coli (O157: H7 ATCC43889) was isolated from human faeces in which haemolytic uremic syndrome was reported. Solid LB agar (Solarbio, China) was used to isolate enterohemorrhagic E. coli. The culture was obtained from the Chinese Institute of Veterinary Drug Control (Beijing, China). The results of necropsy found that using of an orally administered MPX could alleviate the damage of E. coli to the liver, spleen, and the lungs were less affected. According to H&E results in case of an orally administered MPX group considerably relieved duodenum and organs on day 7 and day 28. qRT-PCR results showed orally administered MPX could reduce the inflammation-related factors in the mRNA expression of IL-2 and IL-6 and TNF-α on day 7 and day 28. In addition, orally administered MPX could significantly increase them RNA expression of tight junction proteins Occludin and Zo-1 on day 7 and day 28. The results of immune histochemistry further showed that an orally administered MPX could increase the mRNA expression of MUC2 in jejunum. The above results showed that orally administered MPX could alleviate the attack of E. coli on the intestinal tract of mice, relieve intestinal inflammation, and improve the intestinal barrier function. This study lays a theoretical foundation for adding antimicrobial peptides to food. In orally administered MPX authors can see reducing the mRNA expression of inflammation-related factors, thereby alleviating the intestinal inflammation caused by E. coli infection in mice. Authors can add that orally administered MPX shows an increase in mRNA expression of tight junction protein in intestines and improves the intestinal barrier function. This study lays the foundation for adding antimicrobial peptides to food to relieve inflammation and improve barrier function in clinical practices

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Study of synergistic disinfection by UVC and positive/negative air ions for aerosolized Escherichia coli , Salmonella typhimurium , and Staphylococcus epidermidis in ventilation duct flow

Cited by 12 publications

References 46 publications

Evaluation of Single-Pass Disinfection Performance of Far-UVC Light on Airborne Microorganisms in Duct Flows

Evaluation of Single-Pass Disinfection Performance of Far-UVC Light on Airborne Microorganisms in Duct Flows

Aerosol Transmission of the Pandemic SARS-CoV-2 and Influenza A Virus Was Blocked by Negative Ions

The Effect of Oral Administration of the Antibacterial Peptide MPX on Intestinal Inflammation of Mice in Experimental Infection with Escherichia Coli Strain O157: H7

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