存活在醫院供水系統的水生菌，可經由不同的傳播模式在醫院裡面散佈，引起院內感染的事件發生。目前醫院的院內感控措施，如探病民眾和病人多洗手、病人插管的器械之消毒和醫護人員穿著隔離衣等方法，都無法有效降低院內感染的發生，因為醫護人員與病患與受污染的水接觸是不可避免的，因此，能夠提供安全的用水給院內人員使用，就更顯得重要了。銅銀離子消毒法在歐美地區，廣泛地應用於醫療院所自來水供水系統中退伍軍人菌的消毒，而且有良好的殺菌效果。本研究率先利用銅銀離子消毒法進行綠膿桿菌（Pseudomonas aeruginosa）和嗜麥芽寡食單細菌（Stenotrophomonas maltophilia）之供水管路模型消毒研究，以了解銅銀離子對於這兩株水生菌的消毒效果，可提供醫院發生水生菌引起之院內感染時，作為供水系統消毒的方法之一。本研究結果顯示，銅銀離子在殺菌濃度為0.2/0.02、0.4/0.04 和0.8/0.08 mg/L，對於綠膿桿菌和嗜麥芽寡食單細菌分別作用3、6、12、24、48、72、96和120小時。綠膿桿菌在24小時的消毒期間，銅銀離子可將生物膜中的細菌達到去除99.9%的殺菌效果；對於水中的細菌量也可達到去除99.99%以上的殺菌效果。嗜麥芽寡食單細菌在24小時的消毒期間，銅銀離子可將生物膜中的細菌達到去除99%的殺菌效果；對於在水中的細菌量也可達到去除99.999%以上的殺菌效果。本研究證實銅銀離子消毒法，對綠膿桿菌和嗜麥芽寡食單細菌具有良好的消毒效果，應用銅銀離子消毒法於醫院自來水系統消毒時，不僅能有效控制退伍軍人菌生長，還能同時抑制綠膿桿菌和嗜麥芽寡食單細菌。

Respiratory tract infections caused by Pseudomonas aeruginosa and Stenotrophomonas maltophilia are two of the top 10 leading infections in intensive care units in Taiwan. Prevention of waterborne pathogen-associated nosocomial infections may be achieved by on-site disinfection of the hospital water system. Copper-silver ionization has been validated in peer review journals as one of the best available technology in eradicating Legionella pneumophila from the hospital water system. However, the efficacy of ionization in eradicating P. aeruginosa and S. maltophilia has never been investigated. The objective is to determine the efficacy of ionization in eradicating P. aeruginosa and S. maltophilia in biofilm and planktonic phases. Copper-silver ions concentrations at level of 0.2/0.02, 0.4/0.04 and 0.8/0.08 mg/L achieved significant reduction of both biofilm (>99.9% kill) and planktonic (>99.99%) associated P. aeruginosa within 24 hour of contact. Ions concentration of 0.8/0.08 mg/L can maintain more than 99.9% kill of P. aeruginosa for 120 hr in both phases. Copper-silver ions concentrations at level of 0.2/0.02, 0.4/0.04 and 0.8/0.08 mg/L achieved significant reduction of both biofilm (>99% kill) and planktonic (>99.999%) associated S. maltophilia within the 24 hour of contact. Ionization may have potential to eradicate P. aeruginosa and S. maltophilia in hospital water systems in addition to Legionella. Maintaining ion concentration in water can improve the efficacy of killing P. aeruginosa and S. maltophilia.

Table of Contents
謝誌……………………………………………………………………………………I
中文摘要…………………………………………………………………………… II
Abstract……………………………………………………………………………IV
Table of Contents………………………………………………………………VI
1.0 Introduction………………………………………………………………………1
1.1 Background…………………………………………………………………………1
1.2 Hypothesis…………………………………………………………………………3
1.3 Objective………………………………………………………………………… 3
2.0 Literature review………………………………………………………………4
2.1 Waterborne nosocomial infections……………………………………… 4
2.1.1 Nosocomial infection………………………………………………………… 4
2.1.2 Waterborne pathogens………………………………………………………… 5
2.1.3 Planktonic and biofilm phase………………………………………………6
2.2 Pseudomonas aeruginosa……………………………………………………… 7
2.2.1 Microbiology………………………………………………………………………7
2.2.2 Epidemiology and Infection outbreaks of P. aeruginosa……… 7
2.3 Stenotrophomonas maltophilia………………………………………………8
2.3.1 Microbiology………………………………………………………………………8
2.3.2 Epidemiology and infection outbreaks of S. maltophilia………9
2.4 Prevention strategies……………………………………………………… 10
2.4.1 Legionella pneumophila and Legionnaires’disease………………10
2.4.2 Copper-silver ionization……………………………………………………12
3.0 Materials and Methods……………………………………………………… 15
3.1 Plumbing model………………………………………………………………… 15
3.1.1 Optimal operating conditions…………………………………………… 15
3.2 Preparation of experiments……………………………………………… 16
3.2.1 System cleaning……………………………………………………………… 16
3.2.2 Stock of bacterial solution………………………………………………16
3.3 Measurement of copper and silver ions in the model plumbing system……17
3.4 System operation……………………………………………………………17
3.4.1 System monitoring…………………………………………………..17
3.4.1.1 Biofilm Sampling…………………………………………….18
3.4.1.2 Planktonic Sampling…………………………………………18
3.4.1.3 pH and Temperature Determination………………………….18
3.5 Chemicals for the model plumbing system studies…………………………19
3.5.1 Nutrient solution……………………………………………………..19
3.5.2 Inoculum……………………………………………………………..19
3.5.3 Disinfection………………………………………………………….19
4.0 Results……………………………………………………………………………21
4.1 Disinfection efficacy on Pseudomonas aeruginosa………………………...21
4.1.1 Disinfect efficacy on P. aeruginosa – Sub optimal conditions….......26
4.2 Disinfection result of S. maltophilia………………………………………..31
4.2.1 Disinfection efficacy on S. maltophilia- Sub optimal conditions…...36
5.0 Discussion………………………………………………………………………..41
6.0 Conclusion and Recommendation………………………………………………..44
List of Reference……………………………………………………………………..45


List of Figures
Fig.1. Mode of transmission……………………………………………………...……6
Fig.2. Disinfection Mechanism……………………………………………………....13
Fig.3. Model Plumbing System………………………………………………………20
Fig.4. Comparison of in the different copper-silver ions concentration to eradicated planktonic-associated P. aeruginosa…………………………………………………23
Fig.5. Comparison of in the different copper-silver ions concentration to eradicated biofilm-associated P. aeruginosa…………………………………………………….24
Fig.6. Variation of copper and silver ions was with P. aeruginosa………………......25
Fig.7. Comparison of in the different copper-silver ions concentration to eradicated planktonic-associated P. aeruginosa…………………………………………………28
Fig.8. Comparison of in the different copper-silver ions concentration to eradicated biofilm-associated P. aeruginosa…………………………………………………….29
Fig.9 Variation of copper and silver ions was with P. aeruginosa……………….......30
Fig.10. Comparison of in the different copper-silver ions concentration to eradicated planktonic-associated S. maltophilia…………………………………………………33
Fig.11. Comparison of in the different copper-silver ions concentration to eradicated biofilm-associated S. maltophilia…………………………………………………….34
Fig.12.Variation of copper and silver ions was with S. maltophilia……………….....35
Fig.13. Comparison of in the different copper-silver ions concentration to eradicated planktonic-associated S. maltophilia…………………………………………………38
Fig.14. Comparison of in the different copper-silver ions concentration to eradicated biofilm-associated S. maltophilia…………………………………………………….39
Fig.15.Variation of copper and silver ions was with S. maltophilia……………….....40

List of Tables
Table1. Nosocomial infections related to the hospital Tap water and water reservoirs……………………………………………………………………………14

List of Reference

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