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Prevention of microbial contamination of ultrasonic humidifier

Research Project

Project/Area Number 02670246
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 公衆衛生学
Research InstitutionNara Medical University

Principal Investigator

KATSUI Noriaki  Nara Medical University, School of Medicine, Research Assistant, 医学部, 助手 (70161073)

Project Period (FY) 1990 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
KeywordsUltrasonic humidifier / Microbial contamination / Wash-out method
Research Abstract

Ultrasonic humidifiers contaminated by microbes have been found to cause humidifier lung (humidifier fever) or infectious diseases. To prevent microbial contamination, I devised a wash-out method. By reducing volume of a transducer chamber of a humidifier below a certain level, a dilution rate surpasses a growth rate of microbes in the water of the chamber, and under such environment microbes cannot develop.
First I analyzed the idea of wash-out method theoretically and calculated the desirable volume of a transducer chamber. Then, a humidifier with the transducer chamber of a little volume was constructed. Moreover, I contrived a mechanism that keep empty in a transducer chamber while the humidifier is not in operation. The improved humidifier was operated daily 8 hour period for 6 weeks. The number of bacteria in the water of the chamber was almost below detectable levels throughout the experimental period. In control experiments, viable counts of bacteria increased with time, and reached a level of 10^5 CFU/ml during the second week. In a load test, initial bacterial concentration in water of the transducer chamber which was 3.3X10^5 CFU/ml decreased with time, and reached 70 CFU/ml in 8 hour of operation. Since the residual water in the chamber was removed while the humidifier is not in operation, viable counts were hardly detected after the following day. Because of the results above, the effectiveness of the wash-out method was fully demonstrated. This method demands no change in the mechanism of a humidifier, no additional expense in manufacture and operation, and causes no safety problem.

Report

(3 results)
  • 1991 Annual Research Report   Final Research Report Summary
  • 1990 Annual Research Report
  • Research Products

    (18 results)

All Other

All Publications (18 results)

  • [Publications] 勝井 則明: "Washーout法による超音波加湿器の微生物汚染の防止" 日本防菌防黴学会誌. 18. 485-488 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 勝井 則明: "加湿器の微生物汚染による健康障害" 日本防菌防黴学会誌. 19. 79-87 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 勝井 則明: "低栄養培地を用いた超音波加湿器の微生物汚染調査" 日本防菌防黴学会誌. 19. 619-624 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 勝井 則明: "Washーout法に基づく超音波加湿器の微生物汚染の防止" 空気調和・衛生工学会学術講演会講演論文集. 1149-1152 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Noriaki Katsui: "Decontamination of ultrasonic humidifier by wash-out method" Journal of Applied Bacteriology.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 勝井 則明: "WashーOut法による超音波加湿器の微生物汚染の防止(第2報)ー改良型加湿器の汚染防止効果ー" 日本防菌防黴学会誌.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N. Katsui, S. Asada, E. Kita, M. Emoto, F. Nishikawa and S. Kashiba: "Prevention of microbial contamination of ultrasonic humidifier by wash-out method" J. Antibact. Antifung. Agents. 18. 485-488 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N. Katsui: "Health damage by microbial contamination of humidifier" J. Antibact. Antifung. Agents. 19. 79-87 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N. Katsui, S. Asada, E. Kita and S. Kashiba: "Survey of microbial contamination of ultrasonic humidifiers through the use of a diluted medium" J. Antibact. Antifung. Agents. 19. 619-624 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N. Katsui, E. Kita, H. Nakata, S. Asada and N. Kato: "Prevention of microbial contamination of ultrasonic humidifier based on wash-out method Treatises on the lecture meeting of the Society of Heating" Air-Conditioning and Sanitary Engineers of Japan. 1149-1152 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N. Katsui, E. Kita, S. Asada, N. Kato and S. Kashiba: "Decontamination of ultrasonic humidifier by wash-out method" J. Appl. Bacteriol.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N. Katsui, N. Kato, S. Asada, F. Nishikawa, E. Kita and S. Kashiba: "Prevention of microbial contamination of ultrasonic humidifier by wash-out method --- II. Effectiveness of improved humidifier ---" J. Antibact. Antifung. Agents.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 勝井 則明: "低栄養培地を用いた超音波加湿器の微生物汚染調査" 日本防菌防黴学会誌. 19. 619-624 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] 勝井 則明: "Washーout法に基づく超音波加湿器の微生物汚染防止" 空気調和・衛生工学会学術講演会講演論文集. 1149-1152 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] Noriaki Katsui: "Decontamination of ultrasonic humidifier by washーout method" Journal of Applied Bacteriology.

    • Related Report
      1991 Annual Research Report
  • [Publications] 勝井 則明: "Washーout法による超音波加湿器の微生物汚染の防止" 日本防菌防黴学会誌. 18. 485-488 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] 勝井 則明: "加湿器の微生物汚染による健康障害" 日本防菌防黴学会誌. 19. 79-87 (1991)

    • Related Report
      1990 Annual Research Report
  • [Publications] Noriaki Katsui: "Prevention of microbial contamination of ultrasonic humidifier by washーout method"

    • Related Report
      1990 Annual Research Report

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Published: 1991-04-01   Modified: 2016-04-21  

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