Antibacterial activities of Windscreen wiper fluid (WWF) against Legionella pneumophila

Autor: Yu-Ju Horng, 洪于茹
Rok vydání: 2017
Druh dokumentu: 學位論文 ; thesis
Popis: 106
Literature showed that drivers possess greater risk of acquiring legionellosis, and windscreen wiper systems (WWS) of vehicles are considered as the potential contamination source. Windscreen wiper fluid (WWF) is used to clean the windscreen, research showed that some people use commercial screenwash (CS) and some use household detergent (HD). Previous study had suggest that adding WWF may affect the Legionella growth, and adding household detergent may had lower detection rate of Legionella pneumophila of WWS. The aim of this study was to determine the antimicrobial activity of WWF against L. pneumophila, and to assess the influence on the culturable and viable L. pneumophila of several factors, including the type and the concentration of detergent, contact time, water temperature, pH value and hardness. In this study, three experiments were carried out on the experimental group with the addition of WWF and the control group without WWF. First was short-term antibacterial test at 25 ℃; second was short-term test at 37 ℃; third was long-term test at 37 ℃. Culture method and EMA-qPCR analysis were used for analyzing the concentration of culturable and viable L. pneumophila. The pH value and hardness of WWF were measured at 120 minutes for short term and 30 days for long term test. The results showed that TM had significant effect on the culturable and viable L. pneumophila (P-value 1 or 5 CFU/mL；Viable> 620 cells/mL). Above all, results showed the advantages and disadvantages of different WWF. Influence of the water temperature showed that L. pneumophila may be more resistant the antibacterial effect at 37 °C. For commercial screenwash, results showed that pH value above 8 may have impact on the culturable L. pneumophila, but less for the viable L. pneumophila. As for household detergents, when the environment was more alkaline, the culture of L. pneumophila was more likely to get impaired, but there was no significant effect on the viable L. pneumophila. For commercial screenwash, results showed that hardness between 3-12 mg/L may have more impact on the culturable L. pneumophila, but less on viable L. pneumophila. As for household detergents, the hardness of 3-12 mg/L may increase the culture capacity, and hardness between 30-195 mg/L may decline theculturalbility; besides, the higher the hardness, the higher the concentration of viable L. pneumophila. In addition, there were 18.2% (4/22) of WWF could inhibit the culture and viable L. pneumophila, 13.6% (3/22) had lower viable but nonculture (VBNC), 50% (11/22) had high level concentration of VBNC L. pneumophila, and 18.2 % (4/22) had completely inhibition and had VBNC L. pneumophila at 8 days. Above all, this study confirmed that different ingredient of WWF have different effects on the culture and viable L. pneumophila. Different concentration of detergent, contact time and the water temperature may have different the antibacterial effect, which can provide further recommendation of adding WWF in order to reduce the occurrence of community sporadic disease.
Databáze: Networked Digital Library of Theses & Dissertations
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