著者

NORIKO SHIMASAKI AKIRA OKAUE RITSUKO KIKUNO KATSUAKI SHINOHARA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.23, no.2, pp.61-69, 2018 (Released:2018-06-16)

参考文献数

20

被引用文献数

6 12

---

Exact evaluation of the performance of surgical masks and biohazard protective clothing materials against pathogens is important because it can provide helpful information that healthcare workers can use to select suitable materials to reduce infection risk. Currently, to evaluate the protective performance of nonwoven fabrics used in surgical masks against viral aerosols, a non-standardized test method using phi-X174 phage aerosols is widely performed because actual respiratory viruses pose an infection risk during testing and the phage is a safe virus to humans. This method of using a phage is simply modified from a standard method for evaluation of filter performance against bacterial aerosols using Staphylococcus aureus, which is larger than virus particles. However, it is necessary to perform such evaluations based on the size of the actual pathogen particles. Thus, we developed a new method that can be performed safely using inactivated viral particles and can quantitate the influenza virus in aerosols by antigen-capture ELISA (Shimasaki et al., 2016a) . In this study, we used three different microbial aerosols of phi-X174 phage, influenza virus, and S. aureus and tested the filter efficiency by capturing microbial aerosols for two medical nonwoven fabrics. We compared the filter efficiency against each airborne microbe to analyze the dependency of filter efficiency on the microbial particle size. Our results showed that against the three types of spherical microbe particles, the filter efficiencies against influenza virus particles were the lowest and those against phi-X174 phages were the highest for both types of nonwoven fabrics. The experimental results mostly corresponded with theoretical calculations. We conclude that the filter efficiency test using the phi-X174 phage aerosol may overestimate the protective performance of nonwoven fabrics with filter structure compared to that against real pathogens such as the influenza virus.

著者

TAKESHI SANEKATA TOSHIAKI FUKUDA TAKANORI MIURA HIROFUMI MORINO CHEOLSUNG LEE KEN MAEDA KAZUKO ARAKI TORU OTAKE TAKUYA KAWAHATA TAKASHI SHIBATA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.15, no.2, pp.45-49, 2010 (Released:2010-07-05)

参考文献数

14

被引用文献数

32 65

---

We evaluated the antiviral activity of a chlorine dioxide gas solution (CD) and sodium hypochlorite (SH) against feline calicivirus, human influenza virus, measles virus, canine distemper virus, human herpesvirus, human adenovirus, canine adenovirus and canine parvovirus. CD at concentrations ranging from 1 to 100 ppm produced potent antiviral activity, inactivating ≥ 99.9% of the viruses with a 15 sec treatment for sensitization. The antiviral activity of CD was approximately10 times higher than that of SH.

著者

MASAYUKI ISHIHARA KAORU MURAKAMI KOICHI FUKUDA SHINGO NAKAMURA MASAHIRO KUWABARA HIDEMI HATTORI MASANORI FUJITA TOMOHARU KIYOSAWA HIDETAKA YOKOE

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.22, no.4, pp.223-227, 2017 (Released:2017-12-26)

参考文献数

20

被引用文献数

45 50

---

Hypochlorous acid (HOCl) solution (200 ppm, pH 6) was prepared and evaluated for their stabilities and microbicidal activities. We demonstrated that HOCl is unstable against ultraviolet (UV) light, sunshine, contact with air, and elevated temperature (≧25℃). Furthermore, in the HOCl solution, the presence of excess NH2- or CHO-containing organic compounds such as proteins and carbohydrates, or of inorganic ions such as NO2-, SO3-, PO3-, Fe2+, Cu2+, and CuS, resulted in the rapid consumption of HOCl by oxidation reactions, and significantly decreased the microbicidal activity of the HOCl solution against coliform bacteria and total viable cell count. Thus, production of stable HOCl solution requires formulation in pure water harboring concentrations as low as possible of various compounds and ions, as well as storage in dark and cool conditions (<10℃) to maintain the concentration of HOCl molecules and microbicidal activity.

著者

RITSUKO KUWANA RYUJI YAMAZAWA KIYOSHI ITO HIROMU TAKAMATSU

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.27, no.3, pp.143-151, 2022 (Released:2022-10-08)

参考文献数

27

被引用文献数

1

---

Bacillus cereus is an important foodborne pathogenic bacterium. Although several B. cereus strains have been isolated from the environment, the differences among these strains with respect to spore formation ability and cell morphology need clarification. In this study, a phylogenetic tree was constructed based on the 16S rRNA gene sequences of nine strains of B. cereus. Spore formation and morphology of these nine strains were compared using both phase-contrast and fluorescence microscopy to create an index of the designated sporulation stages. Additionally, to investigate the efficiency of heat-resistant spore formation. Phylogenetic analysis revealed that five strains (ATCC 14579T, NBRC 3457, NBRC 3514, NBRC 3836, and NBRC 13597) clustered together and the remaining four (ATCC 10987, NBRC 3003, NBRC 13494, and NBRC 13690) were genetically distinct from each other. Phase-contrast microscopy revealed significant differences in the sporulation stages among the nine strains. Furthermore, the efficiency of heat-resistant spore formation also differed, even among genetically related strains. In conclusion, a variety of cell morphologies during sporulation were observed among the nine B. cereus strains. We propose a designation of sporulation stages in B. cereus ATCC 14579T, which may be used as an index for evaluating the sporulation progress of B. cereus.

著者

S. HERNÁNDEZ-AQUINO LUIS ALBERTO MIRANDA-ROMERO HIROSHI FUJIKAWA EMA DE JESÚS MALDONADO-SIMÁN BALDOMERO ALARCÓN-ZUÑIGA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.24, no.4, pp.185-192, 2019 (Released:2019-12-26)

参考文献数

55

被引用文献数

16

---

Lactic Acid Bacteria (LAB) are generally recognized as safe. It has been used to increase the shelf-life of fermented products, and its antimicrobial action is based on the metabolites secretions, such as lactic acid, hydrogen peroxide, reuterin, bacteriocins and the like-bacteriocins substances. It has been proven that LAB are able to inhibit deteriorating bacteria of raw meat, but improper handling of live cultures could lead to spoilage. So, the use of their bacteriocins, small antimicrobial peptides, could be an alternative. Besides reducing the number of spoilage bacteria, it seeks to inhibit pathogenic bacteria such as Salmonella, enterohemorrhagic Escherichia coli and Listeria. The food industry uses few bacteriocins and now bacterial resistance has been reported. For that reason, the search of novel bacteriocins produced by LAB is a priority. Moreover, the natural microbiota of meat could be a reservoir of LAB.

著者

EIJI TANESAKA HIRONORI TAKEDA MOTONOBU YOSHIDA

出版者

日本防菌防黴学会

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.18, no.3, pp.143-149, 2013 (Released:2013-09-27)

参考文献数

36

被引用文献数

1

---

This study examined how the addition of a sawdust extract from Castanopsis cuspidata, several aromatic compounds, and copper affected the expression of a phenol-oxidizing enzyme in the white-rot basidiomycete, Lentinula edodes. Compared to liquid media that had not been supplemented with sawdust extract (MYPG), MYPG containing low (MYPG-S100) or high (MYPG-S500) concentrations of sawdust extract had a marked effect on the promotion of mycelial growth. No manganese peroxidase (MnP) production was observed in either MYPG or MYPG-S100 media until 35 days after inoculation. However, MnP production was enhanced by culture in MYPG-S500, with a marked increase observed suddenly at 14 days after inoculation. Northern blot analysis revealed that the transcription of the lemnp2 gene coding extracellular MnP was initially observed at detectable levels at day 10 after the initial inoculation of MYPG-S500, increasing gradually thereafter until days 22-25. However, laccase (Lcc) production was not observed in any of the media until 35 days after inoculation. Addition of 10 mM aromatic compounds - 1,2-benzenediol, 2-methoxyphenol, hydroquinone, and 4-anisidine - into the MYPG-S500 medium completely inhibited MnP production and did not enhance any Lcc production. While the addition of 1 or 2 mM Cu2+ (CuSO4・5H2O) to MYPG-S500 medium completely inhibited MnP production, this Cu2+ addition caused a marked increase in Lcc production at 17 and 6 days after the addition, respectively.

著者

YEON-HEE KIM SI YOUNG LEE

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.25, no.3, pp.173-178, 2020 (Released:2020-09-16)

参考文献数

29

被引用文献数

1 5

---

Viridans group streptococci (VGS) are a common cause of infective endocarditis, and dental plaque is the major source of these bacteria. The present study examined the antibiotic resistance of 635 VGS isolates obtained from dental plaques. Isolates from supragingival plaques were identified using the rapid ID 32 Strep and mini API reader (bioMérieux, France), and minimal inhibitory concentrations (MICs) were determined by a broth microdilution method. High rates of resistance to ampicillin and tetracycline were detected among the isolates. The most resistant species were Streptococcus sanguinis and Streptococcus salivarius. Among the 635 isolates, 9.1% were resistant to erythromycin, and 20.6% to tetracycline. All isolates were sensitive to vancomycin. Resistance to amoxicillin was observed in 0.2% of all isolates. In this study, we showed the incidence of antimicrobial resistance and the susceptibility patterns among 635 VGS isolates from dental plaque.

著者

SATOSHI FUKUZAKI

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.11, no.4, pp.147-157, 2006-12-10 (Released:2011-02-23)

参考文献数

72

被引用文献数

169 397

---

Sodium hypochlorite (NaOCI) is the most widely used disinfectant in the food industry despite the increasing availability of other disinfectants. Sodium hypochlorite fulfills many requirements as the ideal disinfectant and furthermore it has an excellent cleaning action. The effectiveness of sodium hypochlorite in the cleaning and disinfection processes depends on the concentration of available chlorine and the pH of the solution. Hypochlorous acid (HOCI) is a weak acid and dissociates to the hypochlorite ion (-OCI) and proton (H+) depending on the solution pH. It is generally believed that HOCI is the active species in the germicidal action, whereas the concentration of -OCI is a key factor determining the cleaning efficiency. This implies that the optimal pH region of the germicidal activity of sodium hypochlorite differs from that of its cleaning activity. This paper describes the theory and practice of the cleaning and disinfecting operations based on the use of sodium hypochlorite solution.

著者

TOMOKO ONO KOJI YAMASHITA TOMOMI MURAYAMA TOSHIO SATO

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.17, no.3, pp.129-133, 2012 (Released:2012-09-22)

参考文献数

25

被引用文献数

31 41

---

We investigated the microbicidal effect of weak acid hypochlorous solutions of pH 5.0 - 6.0, produced by mixing NaClO and HCl in water, against various bacteria, fungi, and virus in vitro. The weak acid hypochlorous solution had excellent microbicidal effect against a broad microbicidal spectrum of standard strains and clinical isolates in a short time. The microbicidal effects of hypochlorous solutions did not depend on the available chlorine concentration but on the HClO concentration. These results show that the weak acid hypochlorous solution has practical applicability in such places as hospitals and establishments related to the food industry.

著者

ATSUO IWASAWA YOSHIMI NIWANO TAKAYUKI MOKUDAI MASAHIRO KOHNO

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.14, no.3, pp.107-111, 2009 (Released:2010-01-26)

参考文献数

29

被引用文献数

18 29

---

Proanthocyanidin, which consists of (+) catechin, (-) epicatechin and their gallates (15%), (-) epicatechin gallate-dimers, -trimers, and -tetramers (80%), and (-) epicatechin gallate-pentamers, -hexamers, and -heptamers (5%), was evaluated for its antiviral activity against feline calicivirus F9 strain (FCV/F9), which is thought to be a surrogate for noroviruses, and coxsackievirus A7 strain (Cox.A7), which was selected as a representative enteric virus. To achieve a viral inactivation rate of 99% or greater after contact for 10 sec., at least 1 mg/ml and 10 mg/ml of proanthocyanidin were required against FCV/F9 and Cox.A7, respectively. Although the antiviral mechanism of proanthocyanidin is not clear at present, proanthocyanidin may be an effective disinfectant against enteroviruses such as noroviruses.

著者

SHINOBU ODA SEIYA NOMURA MANAMI NAKAGAWA KAZUO SHIN-YA NORITAKA KAGAYA TEPPEI KAWAHARA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.24, no.1, pp.47-56, 2019 (Released:2019-03-18)

参考文献数

33

被引用文献数

1

---

A useful tool for the screening of fungi producing biologically active secondary metabolites such as antibiotics and cytotoxic substances has been developed. An agar plate-organic solvent interface cultivation (A/S-IFC) system, which comprised a hydrophobic organic solvent (upper phase) , a fungal mat (middle phase) and an agar plate (lower phase) , was constructed. The metabolite profiles were compared among the A/S-IFC, a traditional submerged cultivation (SmC) and an extractive liquid surface immobilization (Ext-LSI) system consisted of a hydrophobic solvent (upper phase) , a fungal cells–ballooned microspheres (middle phase) and a liquid medium (lower phase) , with high-performance liquid chromatography-photodiode array detector (HPLC-PDA) . In the A/S-IFC, many hydrophobic metabolites vastly different from those in the SmC were accumulated in the organic phase as with the Ext-LSI. For example, a valuable azaphilone, sclerotiorin, was remarkably produced into the organic phase in the A/S-IFC. The A/S-IFC was applied to the screening of antibiotic-producing fungi. As a result of paper disk method, it was found that 321 isolated among 811 strains produced antifungal metabolites (hit rate, 39.6%) . Furthermore, 8, 23, and 30 strains also produced cytotoxic metabolites against SKOV-3 (human ovary adenocarcinoma) , MESO-1 (human malignant pleural mesothelioma) , and Jurkat cells (immortalized human T lymphocyte) .

著者

KOICHI NAKANISHI AKINORI KOGURE KEIJI DEUCHI RITSUKO KUWANA HIROMU TAKAMATSU KIYOSHI ITO

出版者

日本防菌防黴学会

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.20, no.4, pp.291-295, 2015 (Released:2015-12-22)

参考文献数

9

被引用文献数

1

---

We previously developed a method for evaluating the heat resistance of microorganisms by measuring the transition temperature at which the coefficient of linear expansion of a cell changes. Here, we performed heat resistance measurements using a scanning probe microscope with a nano thermal analysis system. The microorganisms studied included six strains of the genus Bacillus or related genera, one strain each of the thermophilic obligate anaerobic bacterial genera Thermoanaerobacter and Moorella, two strains of heat-resistant mold, two strains of non-sporulating bacteria, and one strain of yeast. Both vegetative cells and spores were evaluated. The transition temperature at which the coefficient of linear expansion due to heating changed from a positive value to a negative value correlated strongly with the heat resistance of the microorganism as estimated from the D value. The microorganisms with greater heat resistance exhibited higher transition temperatures. There was also a strong negative correlation between the coefficient of linear expansion and heat resistance in bacteria and yeast, such that microorganisms with greater heat resistance showed lower coefficients of linear expansion. These findings suggest that our method could be useful for evaluating the heat resistance of microorganisms.

著者

KAZUHIRO HASHIMOTO HIROYUKI FUJII YUJI KAWAKAMI

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.24, no.2, pp.89-96, 2019 (Released:2019-06-17)

参考文献数

39

被引用文献数

7 9

---

In 2017, 2 household washing machines which were used at a house in Saitama prefecture were tested for fungal flora sampling. The fungi were identified in detail via genetic analysis of the ITS region. The number of fungi which were isolated were 8.7×106~6.1×107 cfu/100cm2 and dematiaceous fungi such as Ochroconis musae, Exophiala, Cyphellophora, Knufia epidermidis were dominant. As for Knufia epidermidis, this is the first report for identification from a Japanese household. The number of isolated Cladosporium, which is common in the environment, was fewer compared with the above 4 genera. The identified fungi were Cladosporium halatolerans, which is recently being recognized as the main species of Cladosporium. In our research, we have cleaned the 2 washing machines with different bleaches. Residual fungi was detected in washing machine A, which was cleaned with an oxygen bleach. On the other hand, no fungi was detected in washing machine B, which was cleaned with a chlorine bleach.

著者

KAZUYUKI SOGAWA MIKA KOBAYASHI JUN SUZUKI AKIHIRO SANDA YOSHIO KODERA MASAFUMI FUKUYAMA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.23, no.2, pp.77-80, 2018 (Released:2018-06-16)

参考文献数

19

被引用文献数

2 4

---

Group A streptococcus is a bacterium that resides in the throat and skin and causes respiratory infection and occasionally glomerulonephritis and rheumatic fever. Streptolysin O (SLO) produced by Streptococcus pyogenes (S. pyogenes) binds to the cell membrane, particularly to that of white and red blood cells, and is toxic to the cells and tissue. In this study, we evaluated the inhibitory activity of water-soluble polyphenols in olives (Olea europaea) against SLO-induced hemolysis. Hydroxytyrosol inhibited SLO-induced hemolytic activity, and the amount required for 50% inhibition of hemolysis was 1.30 µg. These findings suggest that the water-soluble polyphenols contained in olives have inhibitory activity against SLO-induced hemolysis.

著者

HIROFUMI MORINO TOSHIAKI FUKUDA TAKANORI MIURA CHEOLSUNG LEE TAKASHI SHIBATA TAKESHI SANEKATA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.14, no.4, pp.147-153, 2009 (Released:2010-02-23)

参考文献数

33

被引用文献数

22 29

---

The efficacy of gaseous chlorine dioxide (ClO2) against feline calicivirus (FCV), a norovirus surrogate, in the dry and the wet states on a hard surface was evaluated. We demonstrated that low-concentration ClO2 gas (mean 0.08 ppm, 0.22 μg/l) could inactivate FCV in the wet state with 0.5% fetal bovine serum (FBS) within 6 h in 45 to 55% relative humidity (RH) (>3 log10 reductions) and FCV in the dry state with 2% FBS (percentage of FBS in the viral suspension) within 10 h in 75 to 85% RH (>3 log10 reductions) at 20°C, respectively. Furthermore, a <0.3 ppm concentration of ClO2 gas (mean 0.26 ppm, 0.73 μg/l) could inactivate (below the detection limit) FCV in the dry state with 5% FBS within 24 h in 75 to 85% RH at 20°C. In contrast, in 45 to 55% RH at 20°C, ClO2 gas had little effect even when the FCV in the dry state was exposed to high-concentration ClO2 (mean 8 ppm, 22.4 μg/l) for 24 h. These results suggest that humidity plays an important role in the inactivation by ClO2 gas of FCV in the dry state. According to the International Chemical Safety Card, threshold limit values for ClO2 gas are 0.1 ppm as an 8-h time-weighted average and 0.3 ppm as a 15 min short-term exposure limit. From these data, we propose that the treatment of wet areas of human activity such as kitchens, toilets, etc., with low-concentration ClO2 gas would be useful for reducing the risk of infection by noroviruses (NV) without adverse effects. In addition, we believe that the application of a combination of a <0.3 ppm concentration of ClO2 gas and a humidifier in places without human activity may make it possible to inactivate NV in the dry state on any surface within a contaminated room without serious adverse effects.

著者

YOKO SATO MASAYUKI ISHIHARA SHINGO NAKAMURA KOICHI FUKUDA MASAHIRO KUWABARA TOMOHIRO TAKAYAMA SUMIYO HIRUMA KAORU MURAKAMI MASANORI FUJITA HIDETAKA YOKOE

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.24, no.2, pp.103-108, 2019 (Released:2019-06-17)

参考文献数

19

被引用文献数

16 21

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The bactericidal activity of heated bio-shell calcium oxide (BiSCaO) powder suspension (pH 12.4) , hypochlorous acid (HClO; pH 6), sodium hypochlorite (NaClO; pH 8) , povidone-iodine (Isodine solution®) , and chlorhexidine gluconate (Hibiscrub®) under organic matter contaminated environments were compared for tests conducted on wood scraps and pig skin pieces that were incubated with normal bacterial flora (total viable counts and coliform bacteria) . The test results showed that BiSCaO suspension had higher bactericidal activity than HClO and NaClO. Furthermore, more than 10-fold higher concentrations of antiseptics such as povidone-iodine and chlorhexidine gluconate were required to achieve bactericidal activity comparable to that of BiSCaO suspension. Our results demonstrate the possibility of using BiSCaO suspension under organic matter contaminated environments as a disinfectant for environmental and food hygiene applications.

著者

SHINKURO TAKENAKA TAKESHI YOSHIKAWA SHUSAKU KADOWAKI SUGURU OKUNISHI HIROTO MAEDA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.22, no.2, pp.79-87, 2017 (Released:2017-06-27)

参考文献数

28

被引用文献数

3 5

---

A marine raphidophyte Heterosigma akashiwo is a causative agent of harmful microalgal blooms, which often cause the massive mortality of aquacultured finfish. In the present study, the Pacific oyster Crassostrea gigas was reared with H. akashiwo, and effect of the microalga on filter-feeding behavior and microflora of the gastrointestinal tract was investigated. The intake of the raphidophyte cells inhibited the molluscan filter-feeding activities, suggesting the negative physiological effect of the microalgal cell contents. However, the bivalves ingested the H. akashiwo cells to the same extent as the diatom Chaetoceros calcitrans, a non-harmful indicator to estimate the filtration rate, showing a continuation of their non-selective ingestion of the phytoplankton. Microflora of the oyster soft tissue was dominated by bacteria affiliated with the family Rhodobacteraceae, some of which are associated with microalgae. In addition, the Bacteroidetes species, in which algicidal bacteria are included, were also found in the bivalve individuals exposed to H. akashiwo. These results suggested that the ingested phytoplankton affected the microbial flora in the gastrointestinal tracts, some constituents of which helped the mollusc assimilate the ingested red tide phytoplankton. This study will provide beneficial information to clarify mechanisms by which the oyster evades the ichthyotoxicity of harmful microalgae and the participation of the intestinal microorganisms in these processes.

著者

AKIHIRO SUZUKI AKIRA EMOTO AKIHIRO SHIRAI KENTARO NAGAMATSU

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.27, no.1, pp.1-7, 2022 (Released:2022-03-20)

参考文献数

30

被引用文献数

5

---

A kind of citrus fruit with special flavor, Citrus sudachi harvested in Japan, are exported to various countries. However, the Citrus sudachi needs to be sterilized using aqueous solution of sodium hypochlorite because there is a possibility of the adhesion of citrus bacterial canker (CBC) which is not found in Europe. Due to the sterilization with time-consuming work, a more effective decontamination technique is required. A decontamination method using ultraviolet (UV) light irradiation is thus anticipated. Especially, the use of light emitting diodes (LEDs) wi UV light has many advantages in terms of energy consumption, lifetime, and compactness; although an appropriate method is yet to be established. In this study, we evaluate the fundamental effectiveness of UV-LED decontamination on the basis of the bactericidal ability on CBC in petri dishes, using six kinds of UV-LEDs (265, 280, 285, 300, 310, and 365 nm) . For each irradiation, the resultant bactericidal abilities (BAs) were evaluated precisely taking into account the differences in their optical absorptions. In addition, BAs per unit photon number were also estimated, as a fundamental wavelength-dependence of BA. As a result, the effectiveness of UV-LED irradiation with relatively short wavelengths was demonstrated clearly.

著者

AKIKO EDAGAWA NORIHIRO MATSUDA TORU OGURA KENICHI UEZONO SHINJI IZUMIYAMA AKIRA FUJII

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.26, no.4, pp.187-192, 2021 (Released:2022-01-08)

参考文献数

15

---

Microbiological contamination inside rubber ducks floating in the bathtub at a "duck bath" of a bathing facility was analyzed by examining bacterial and amoebic counts. The results of microbial tests, such as standard plate count, heterotrophic plate count and Legionella-LAMP (Loopmediated isothermal amplification) , showed that microbial contamination increased in the rubber ducks over time. When the ducks were washed with sodium hypochlorite, those microbial contaminations were not detected; but when the ducks were washed with an electrolyzed water, the standard plate counts and the heterotrophic plate counts were detected in the amount of 103 per duck in the wipe samples. Without proper washing of rubber ducks, bacteria and free-living amoeba can grow and colonize biofilms, and can thereby cause infection in humans. Also, microbial contamination inside ducks may reduce chlorination of the entire bathtub and cause bacterial infection such as Legionellosis from the bathtub water.

著者

MASASHI UEMA KENZO YONEMITSU YOSHIKA MOMOSE YOSHIKAZU ISHII KAZUHIRO TATEDA TAKAO INOUE HIROSHI ASAKURA

出版者

The Society for Antibacterial and Antifungal Agents, Japan

雑誌

Biocontrol Science (ISSN:13424815)

巻号頁・発行日

vol.26, no.2, pp.119-125, 2021 (Released:2021-06-04)

参考文献数

19

被引用文献数

8

---

There is a worldwide attempt to develop prevention strategies against SARS-CoV-2 transmission. Here we examined the effectiveness of tungsten trioxide (WO3)-based visible light-responsive photocatalyst on the inactivation of SARS-CoV-2 under different temperatures and exposure durations. The viral titer on the photocatalyst-coated glass slides decreased from 5.93 ± 0.38 logTCID50 /mL to 3.05 ±. 25 logTCID50/mL after exposure to 3,000 lux of the visible light irradiation for 6h at 20℃. On the other hand, lighting without the photocatalyst, or the photocatalyst-coat without lighting retained viral stability. Immunoblotting and electron microscopic analyses showed the reduced amounts of spike protein on the viral surface after the photocatalyst treatment. Our data suggest a possible implication of the photocatalyst on the decontamination of SARS-CoV-2 in indoor environments, thereby preventing indirect viral spread.