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Li N, Cai QM, Hu NY, Jiang SL, Chen FQ, Hu QQ, Yang F, He CZ. Pyrosequencing analysis of bacterial community changes in dental unit waterlines after chlorogenic acid treatment. Front Cell Infect Microbiol 2024; 14:1303099. [PMID: 38299116 PMCID: PMC10828043 DOI: 10.3389/fcimb.2024.1303099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024] Open
Abstract
Introduction The contamination of dental unit waterlines (DUWLs) poses a significant risk of cross-infection in dentistry. Although chemical disinfectants have been effective in reducing number of bacteria, they do have limitations. Methods This study aimed to investigate the potential of chlorogenic acid, a natural substance with broadspectrum antibacterial properties, for treating DUWLs. Over a period of three months, we analyzed the microbial communities in 149 DUWLs samples collected from 5 dental units using high-throughput pyrophosphate sequencing. Results The results revealed that chlorogenic acid treatment had a significant impact on the microbial community profile in the DUWLs, with the most significant changes occurring within the first 15 days and stabilization observed in the last 30 days. The predominant genera detected in the samples were Bacteroides, Lactobacillus, Streptococcus, Methylobacterium, and Phreatobacter. Additionally, the relative abundance of certain beneficial bacteria, such as Alloprevotella, Roseburia, and Blautia, increased, while the presence of opportunistic pathogens like Mycobacteria significantly decreased. The functional prediction analysis using the KEGG database indicated a decrease in the pathogenicity of the bacterial community in the DUWLs following chlorogenic acid treatment. Discussion This study introduces a novel approach for the prevention and treatment of infections associated with dental care.
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Affiliation(s)
- Na Li
- Department of Stomatology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Nursing School, Nanchang University, Nanchang, China
| | - Qin-Ming Cai
- The First Affiliated Hospital of Nanchang University, School of Public Health, Nanchang University, Nanchang, China
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Ni-Ya Hu
- The First Affiliated Hospital of Nanchang University, School of Public Health, Nanchang University, Nanchang, China
| | - Shu-ling Jiang
- Department of Stomatology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
- Nursing School, Nanchang University, Nanchang, China
| | - Fu-Qing Chen
- Department of Stomatology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Qiao-Qiao Hu
- Department of Stomatology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Fen Yang
- Department of Stomatology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Chao-Zhu He
- Nursing School, Nanchang University, Nanchang, China
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Lv X, Yan K, Han X, Wang F, Ma Y, Zhang S, Wang X. Effective disinfecting of negative pressure pipelines of DCUs reduces the risk of cross infection in dental care. J Oral Microbiol 2024; 16:2299538. [PMID: 38193138 PMCID: PMC10773641 DOI: 10.1080/20002297.2023.2299538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/14/2023] [Indexed: 01/10/2024] Open
Abstract
Objectives Microbial contamination of various accessory parts of the dental chair units (DCUs) is an essential source of cross infection, while the accessories of the crucial suction function are usually overlooked. In this study, we aim to find an effective disinfectant and a cost-effective method to remove bacterioplankton and bacterial biofilm deposited in the negative pressure suction pipelines to control cross infection during dental treatment. Methods Double-chain quaternary ammonium salt disinfectant (Orotol Plus®), 3% hydrogen peroxide solution plus multi-enzyme cleaning agent and chlorine disinfectant are used to clean and disinfect the negative pressure pipelines of DCUs. Microbiological examinations, air condition detection, corrosion tests and gene sequencing are performed. Results Little bacteria grow in the pipelines disinfected with double-chain quaternary ammonium salt disinfectants, destruction of biofilms in these pipelines appears, and multi-resistant bacteria cannot be detected. Minimal damage to metal sheets and fittings is caused by double-chain quaternary ammonium salt disinfectants. Conclusion Double-chain quaternary ammonium salt disinfectant has excellent bactericidal ability and anti-biofilm effect, and it is less corrosive to the fittings of the pipelines. Thus, the double-chain quaternary ammonium salt disinfectant is a potential novel disinfectant for negative pressure suction pipelines of DCUs to control cross infection during dental treatment. Clinical significance It is essential to add all these data to our dental practice to control cross infection with a broader landscape.
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Affiliation(s)
- Xuerong Lv
- Department of Periodontology, Jiangsu Province Key Laboratory of Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Ke Yan
- Department of Periodontology, Jiangsu Province Key Laboratory of Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Xiang Han
- Department of Periodontology, Jiangsu Province Key Laboratory of Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Feiyang Wang
- Department of Periodontology, Jiangsu Province Key Laboratory of Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Yuzhuo Ma
- Department of Periodontology, Jiangsu Province Key Laboratory of Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Shougang Zhang
- Department of Disinfection and Vector Control, Nanjing Center for Disease Control and Prevention, China
| | - Xiaoqian Wang
- Department of Periodontology, Jiangsu Province Key Laboratory of Oral Diseases, Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
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Grealy L, Wilson P, Gillen C, Duffy É, Healy ML, Daly B, Polyzois I, Van Harten M, Dougall A, Brennan GI, Coleman DC, McManus BA. Immersion of debrided diabetic foot ulcer (DFU) tissue in electrochemically generated pH neutral hypochlorous acid significantly reduces the microbial bioburden: whole-genome sequencing of Staphylococcus aureus, the most prevalent species recovered. J Hosp Infect 2023:S0195-6701(23)00179-2. [PMID: 37308064 DOI: 10.1016/j.jhin.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/08/2023] [Accepted: 06/08/2023] [Indexed: 06/14/2023]
Abstract
BACKGROUND Diabetic foot ulcer infections (DFUIs) are the leading cause of lower limb amputations, mediated predominantly by Staphylococcus aureus. pH neutral electrochemically-generated hypochlorous acid (anolyte) is a non-toxic, microbiocidal agent with significant potential for wound disinfection. AIMS To investigate both the effectiveness of anolyte for microbial bioburden reduction in debrided ulcer tissues and the population of resident S. aureus. METHODS Fifty-one debrided tissues from 30 people with type II diabetes were aliquoted by wet weight and immersed in 1 or 10 ml volumes of anolyte (200 parts per million) or saline for three min. Microbial loads recovered were determined in colony forming units/g (CFU/g) of tissue following aerobic, anaerobic and staphylococcal-selective culture. Bacterial species were identified and 50 S. aureus isolates from 30 tissues underwent whole-genome sequencing (WGS). FINDINGS The ulcers were predominantly superficial, lacking signs of infection (39/51, 76.5%). Of the 42/51 saline-treated tissues yielding ≥105 CFU/g, a microbial threshold reported to impede wound-healing, only 4/42 (9.5%) were clinically-diagnosed DFUIs. Microbial loads from anolyte-treated tissues were significantly lower than saline-treated tissues using 1 ml (1065-fold, 2.0 log) and 10 ml (8216-fold, 2.1 log) immersion volumes (p<0.0005). Staphylococcus aureus was the predominant species recovered (44/51, 86.3%) and 50 isolates underwent WGS. All were meticillin-susceptible and comprised 12 sequence types (STs), predominantly ST1, ST5 and ST15. Whole-genome multilocus sequence typing identified three clusters of closely related isolates from 10 patients indicating inter-patient transmission. CONCLUSIONS Short immersions of debrided ulcer tissue in anolyte significantly reduced microbial bioburden: a potential novel DFUI treatment.
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Affiliation(s)
- Liam Grealy
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Pauline Wilson
- Department of Endocrinology & Diabetes, St. James's Hospital, Dublin, Ireland
| | - Corey Gillen
- Department of Endocrinology & Diabetes, St. James's Hospital, Dublin, Ireland
| | - Éilish Duffy
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Marie-Louise Healy
- Department of Endocrinology & Diabetes, St. James's Hospital, Dublin, Ireland
| | - Blánaid Daly
- Division of Public and Child Dental Health, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Ioannis Polyzois
- Division of Restorative Dentistry and Periodontology, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Maria Van Harten
- Division of Public and Child Dental Health, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Alison Dougall
- Division of Public and Child Dental Health, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Gráinne I Brennan
- National MRSA Reference Laboratory, St. James's Hospital, Dublin, Ireland
| | - David C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Brenda A McManus
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, The University of Dublin, Trinity College Dublin, Dublin, Ireland.
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Hussain Akbar J, Behbehani J, Karched M. Biofilm growth and microbial contamination of dental unit waterlines at Kuwait University dental center. FRONTIERS IN ORAL HEALTH 2023; 3:1071018. [PMID: 36698450 PMCID: PMC9868918 DOI: 10.3389/froh.2022.1071018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 12/05/2022] [Indexed: 01/12/2023] Open
Abstract
Biofilm formation in dental unit waterlines and the resulting microbial contamination of the water in the system has become a significant problem. Contaminated water in the dental units is a major concern in dental clinics due to potential risk of causing infections particularly in elderly and immunocompromised patients. The aim of this study was at first to determine microbial contamination of the dental unit waterlines and then to study the efficacy of a comprehensive disinfection protocol on decreasing the microbial load. Water samples were collected before and after disinfection procedure from handpieces and water storage bottles from the dental units, a small 1-cm tubing was cut from each unit and subjected to microbiological culture on different growth media. Identification of the predominant species was achieved by 16S rRNA gene sequencing. Microbial growth was observed in samples collected from all dental units. Upon disinfection procedure, microbial contamination in the water samples and in the tubing surfaces was significantly reduced (P > 0.05). 16S rRNA gene sequencing revealed the presence of several species belonging to the genera Staphylococcus, Corynebacterium and Roseomonas, some of which are implicated in human infections. Aggravation of the biofilm growth on the tubing surfaces and the microbial contamination in the water can be effectively controlled by implementing appropriate and routine disinfection protocols. This may help protect the dental unit staff and the patients being exposed to the risk of infections.
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Affiliation(s)
- Jaber Hussain Akbar
- Department of Restorative Sciences, Faculty of Dentistry, Kuwait University, Kuwait City, Kuwait
| | - Jawad Behbehani
- Department of Restorative Sciences, Faculty of Dentistry, Kuwait University, Kuwait City, Kuwait
| | - Maribasappa Karched
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, Kuwait City, Kuwait,Correspondence: Maribasappa Karched
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Wu M, Shi Z, Yu X, Xu Y, Jin X, Zhang L, Fu B. Disinfection methods of dental unit waterlines contamination: a systematic review. J Med Microbiol 2022; 71. [PMID: 35670283 DOI: 10.1099/jmm.0.001540] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background. Severe contamination of dental unit waterlines was found in healthcare settings. The benefits of decontamination methods are controversial. The aim of this review was to systematically evaluate disinfection methods in contamination control of dental unit waterlines.Methods. The terms 'dental unit waterline(s) or DUWL(s) or dental unit water line(s)' were searched through PubMed, Cochrane Library, Embase, Web of Science and Scopusup to 31 May 2021. The DUWLs' output water was incubated on R2A agar at 20-28 °C for 5-7 days to evaluate heterotrophic mesophilic bacteria. The risk of bias was evaluated by a modified Newcastle-Ottawa quality assessment scale.Results. Eighteen papers from the literature were included. One study indicated that water supply played a crucial role in disinfecting DUWLs. Three studies indicated that flushing decreased bacteria counts but did not meet the American CDC standard (500 c.f.u. ml-1). All chlorine- and peroxide-containing disinfectants except sodium hypochlorite in one of 15 studies as well as three mouthrinses and citrus botanical extract achieved the standard (≤500 c.f.u. ml-1). The included studies were of low (1/18), moderate (6/18) and high (11/18) quality.Conclusion. Independent water reservoirs are recommended for disinfecting DUWLs using distilled water. Flushing DUWLs should be combined with disinfections. Nearly all the chlorine-, chlorhexidine- and peroxide-containing disinfectants, mouthrinses and citrus botanical extract meet the standard for disinfecting DUWLs. Alkaline peroxide would lead to tube blockage in the DUWLs. Regularly changing disinfectants can reduce the risk of occurrence of disinfectant-resistant strains of microbes.
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Affiliation(s)
- Mengting Wu
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, PR China
| | - Zhiwei Shi
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, PR China
| | - Xuefen Yu
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, PR China
| | - Yuedan Xu
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, PR China
| | - Xinyang Jin
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, PR China
| | - Ling Zhang
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, PR China
| | - Baiping Fu
- Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou 310006, PR China
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Son K, Son YT, Jin MU, Lee KB. Satisfaction Factors with a Dental Unit Chair System in South Korea: A Dentist's Perspective. Healthcare (Basel) 2022; 10:healthcare10030437. [PMID: 35326915 PMCID: PMC8950680 DOI: 10.3390/healthcare10030437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/14/2022] [Accepted: 02/23/2022] [Indexed: 12/02/2022] Open
Abstract
This study aimed to survey users’ satisfaction with a dental unit chair in order to highlight the elements affecting the dentist’s satisfaction. The questionnaire items were drawn up with seven components that constitute a dental unit chair, including the light, patient seat, foot controller, water fountain and cuspidor, monitor, bracket table and controller, and dentist chair. With these questionnaire elements, a pilot experiment was conducted to test the reliability, and reliability analysis was conducted. The scale reliability was checked using Cronbach’s alpha coefficient. Bartlett’s test of sphericity, the Kaiser-Meyer-Olkin (KMO) measure, and factor analysis were performed to test whether the items would constitute appropriate questionnaire items for the survey. The survey was conducted with 26 dentists with more than three years of clinical experience. A correlation analysis was conducted using Pearson’s correlation coefficient (PCC) (α = 0.05) to analyze the impact of the factors on the overall satisfaction with the dental unit chair. The items that were strongly correlated with the overall satisfaction score of the dental unit chair were the design and appearance quality of the dental unit chair (PCC = 0.781), its maintenance (PCC = 0.784), and the overall satisfaction with the water fountain and cuspidor (PCC = 0.703) (p < 0.05). Most of the questionnaire items could affect the overall satisfaction with the dental unit chair. Additionally, because the design and appearance quality, maintenance, and overall satisfaction with the water fountain and cuspidor may have the greatest impact on the overall satisfaction with the dental unit chair, the improvement of these elements may bring about the enhancement of the overall satisfaction.
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Affiliation(s)
- Keunbada Son
- Advanced Dental Device Development Institute, Kyungpook National University, Daegu 41940, Korea; (K.S.); (Y.-T.S.)
| | - Young-Tak Son
- Advanced Dental Device Development Institute, Kyungpook National University, Daegu 41940, Korea; (K.S.); (Y.-T.S.)
- Department of Dental Science, Graduate School, Kyungpook National University, Daegu 41940, Korea
| | - Myoung-Uk Jin
- Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
- Correspondence: (M.-U.J.); (K.-B.L.); Tel.: +82-053-600-7674 (K.-B.L.)
| | - Kyu-Bok Lee
- Advanced Dental Device Development Institute, Kyungpook National University, Daegu 41940, Korea; (K.S.); (Y.-T.S.)
- Department of Prosthodontics, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
- Correspondence: (M.-U.J.); (K.-B.L.); Tel.: +82-053-600-7674 (K.-B.L.)
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Ji XY, Fei CN, Zhang Y, Zhang W, Liu J, Dong J. Evaluation of bacterial contamination of dental unit waterlines and use of a newly designed measurement device to assess retraction of a dental chair unit. Int Dent J 2016; 66:208-14. [PMID: 27000421 DOI: 10.1111/idj.12225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION Dental unit waterline (DUWL) output water is delivered through instruments of a dental chair unit (DCU) to irrigate and cool teeth. However, these waterlines can be heavily contaminated with bacteria. AIM The purpose of the present study was to assess retraction and investigate the contamination level and prevalence of bacteria in DUWL output water. METHODS Fifty-eight DCUs were randomly selected from 30 hospitals in 10 districts of Tianjin, one of the four special municipalities of China. A unique sampling connector was used in place of the dental handpiece to collect water samples. Evaluation of retraction was accomplished using a retraction measurement device designed in accordance with the International Standard ISO 7494-2:2015(E). RESULTS A total of 263 water samples were collected, and the highest concentration of bacteria [1.8 × 10(6) colony-forming units (CFU)/mL] was found in the handpiece group. Thirty (51.72%) water samples in the handpiece group and 21 (36.21%) in the air/water syringe groups were cultured, yielding colony counts of > 500 CFU/mL. Potential infectious agents, such as Bacillus cereus, Kocuria kristinae and Pseudomonas fluorescens, were isolated from the water samples. Thirty (51.72%) DCUs failed the retraction evaluation. There was a significant, positive correlation (P < 0.05) between the concentration of bacteria in the water sample and the retracted volume. CONCLUSION It is of paramount importance to increase compliance with the standards for controlling DUWL contamination. Routine microbial monitoring and evaluation of retraction are necessary to provide high-quality water for use in dental treatment.
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Affiliation(s)
- Xue-Yue Ji
- Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Chun-Nan Fei
- Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Ying Zhang
- Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Wei Zhang
- Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Jun Liu
- Tianjin Centers for Disease Control and Prevention, Tianjin, China
| | - Jie Dong
- Tianjin Centers for Disease Control and Prevention, Tianjin, China
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Yun KO, Kim HY. A Study Regarding Bacterial Contamination of Surfaces in Dental Offices. KOREAN JOURNAL OF CLINICAL LABORATORY SCIENCE 2015. [DOI: 10.15324/kjcls.2015.47.4.279] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Boyle MA, O'Donnell MJ, Russell RJ, Galvin N, Swan J, Coleman DC. Overcoming the problem of residual microbial contamination in dental suction units left by conventional disinfection using novel single component suction handpieces in combination with automated flood disinfection. J Dent 2015; 43:1268-79. [PMID: 26248229 DOI: 10.1016/j.jdent.2015.07.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVES Decontaminating dental chair unit (DCU) suction systems in a convenient, safe and effective manner is problematic. This study aimed to identify and quantify the extent of the problems using 25 DCUs, methodically eliminate these problems and develop an efficient approach for reliable, effective, automated disinfection. METHODS DCU suction system residual contamination by environmental and human-derived bacteria was evaluated by microbiological culture following standard aspiration disinfection with a quaternary ammonium disinfectant or alternatively, a novel flooding approach to disinfection. Disinfection of multicomponent suction handpieces, assembled and disassembled, was also studied. A prototype manual and a novel automated Suction Tube Cleaning System (STCS) were developed and tested, as were novel single component suction handpieces. RESULTS Standard aspiration disinfection consistently failed to decontaminate DCU suction systems effectively. Semi-confluent bacterial growth (101-500 colony forming units (CFU) per culture plate) was recovered from up to 60% of suction filter housings and from up to 19% of high and 37% of low volume suction hoses. Manual and automated flood disinfection of DCU suction systems reduced this dramatically (ranges for filter cage and high and low volume hoses of 0-22, 0-16 and 0-14CFU/plate, respectively) (P<0.0001). Multicomponent suction handpieces could not be adequately disinfected without prior removal and disassembly. Novel single component handpieces, allowed their effective disinfection in situ using the STCS, which virtually eliminated contamination from the entire suction system. CONCLUSION Flood disinfection of DCU suction systems and single component handpieces radically improves disinfection efficacy and considerably reduces potential cross-infection and cross-contamination risks. CLINICAL SIGNIFICANCE DCU suction systems become heavily contaminated during use. Conventional disinfection does not adequately control this. Furthermore, multicomponent suction handpieces cannot be adequately disinfected without disassembly, which is costly in time, staff and resources. The automated STCS DCU suction disinfection system used with single component handpieces provides an effective solution.
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Affiliation(s)
- M A Boyle
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland
| | - M J O'Donnell
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland
| | - R J Russell
- Department of Microbiology, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland
| | - N Galvin
- Moyderwell Dental Clinic, Tralee, County Kerry, Ireland
| | - J Swan
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland
| | - D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland.
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Repeated detection of microbes in beverages dispensed from soda fountain machines and the effect of flushing on microbial density. Int J Food Microbiol 2013; 163:218-22. [DOI: 10.1016/j.ijfoodmicro.2013.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 01/31/2013] [Accepted: 03/09/2013] [Indexed: 11/22/2022]
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Barbot V, Robert A, Rodier MH, Imbert C. Update on infectious risks associated with dental unit waterlines. ACTA ACUST UNITED AC 2012; 65:196-204. [PMID: 22469485 DOI: 10.1111/j.1574-695x.2012.00971.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 02/08/2012] [Accepted: 03/22/2012] [Indexed: 11/28/2022]
Abstract
Modern dental chair units consist of a network of interconnected narrow-bore plastic tubes called dental unit waterlines (DUWLs). The water delivered by these DUWLs acts as both a coolant for a range of instruments and an irrigant during dental treatments. The quality of water is of considerable importance because both patients and dental team are regularly exposed to water and aerosols generated by dental equipment. Studies have demonstrated that DUWLs provide a favourable environment for microbial proliferation and biofilm formation, and that water is consequently often contaminated with high densities of various microorganisms (bacteria, fungi, protozoa, viruses). The presence of high levels of microbial contamination may be a health problem for dentists and patients, especially those who are immunocompromised. The current status of knowledge on microbial contamination of DUWLs is presented, with an emphasis on the infectious risk associated with DUWLs and on the various approaches for disinfecting and protecting DUWLs.
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Affiliation(s)
- Vanessa Barbot
- Laboratoire de Chimie et Microbiologie de l'Eau, Université de Poitiers, Poitiers, France.
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Bristela M, Skolka A, Schmid-Schwap M, Piehslinger E, Indra A, Wewalka G, Stauffer F. Testing for aerobic heterotrophic bacteria allows no prediction of contamination with potentially pathogenic bacteria in the output water of dental chair units. GMS KRANKENHAUSHYGIENE INTERDISZIPLINAR 2012; 7:Doc12. [PMID: 22558046 PMCID: PMC3334951 DOI: 10.3205/dgkh000196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background: Currently, to our knowledge, quality of output water of dental chair units is not covered by specific regulations in the European Union, and national recommendations are heterogeneous. In Germany, water used in dental chair units must follow drinking water quality. In the United States of America, testing for aerobic heterotrophic bacteria is recommended. The present study was performed to evaluate whether the counts of aerobic heterotrophic bacteria correlate with the presence of potentially pathogenic bacteria such as Legionella spp. or Pseudomonas aeruginosa. Methods: 71 samples were collected from 26 dental chair units with integrated disinfection device and 31 samples from 15 outlets of the water distribution pipework within the department were examined. Samples were tested for aerobic heterotrophic bacteria at 35°C and 22°C using different culture media and for Legionella spp. and for Pseudomonas aeruginosa. Additionally, strains of Legionella pneumophila serogroup 1 were typed with monoclonal antibodies and representative samples of Legionella pneumophila serogroup 1 were typed by sequence based typing. Results: Our results showed a correlation between different agars for aerobic heterotrophic bacteria but no correlation for the count of aerobic heterotrophic bacteria and the presence of Legionella spp. or Pseudomonas aeruginosa. Conclusion: Testing for aerobic heterotrophic bacteria in output water or water distribution pipework within the departments alone is without any value for predicting whether the water is contaminated with potentially pathogenic bacteria like Legionella spp. or Pseudomonas aeruginosa.
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Affiliation(s)
- Margit Bristela
- Bernhard Gottlieb University Clinic of Dentistry, Department of Fixed and Removable Prosthodontics, Medical University Vienna, Austria
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Control of bacterial contamination of washbasin taps and output water using Ecasol: a one-year study. J Hosp Infect 2012; 80:288-92. [DOI: 10.1016/j.jhin.2012.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/25/2012] [Indexed: 11/21/2022]
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Su J, Deng XH, Sun Z. A 10-year survey of compliance with recommended procedures for infection control by dentists in Beijing. Int Dent J 2012; 62:148-53. [PMID: 22568740 DOI: 10.1111/j.1875-595x.2011.00107.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVES This study aimed to survey changes in practices of infection control (IC) procedures by dentists in Beijing between 2000 and 2010. METHODS Data were based on the feedback of 592 and 769 dentists surveyed in 2000 and 2010, respectively. Statistical analysis was conducted using Pearson's chi-squared test. RESULTS Response rates of 95% (2000) and 94% (2010) were achieved. The percentages of dentists who had received training in IC were 62.96% (2000) and 76.21% (2010). Improvements in practices in 2010 over those in 2000 included increases in: the percentage of vaccination for hepatitis B virus from 32.66% to 68.14%; the routine use of gloves from 73.31% to 99.73%; the use of face shields or eyewear as protection against splatter during dental treatment from 13.94% to 95.45%; the use of protective gowns from 14.51% to 54.23%; the use of high-volume suction from 11.19% to 74.34%; routine changing of gloves between patients from 63.25% to 99.22%; pressured steam sterilisation of dental handpieces between patients from 41.24% to 96.10%, and the flushing of dental unit waterlines after each treatment from 42.01% to 73.49%. CONCLUSIONS Although compliance with recommended IC practices by dentists in Beijing improved between 2000 and 2010, not all dentists are properly familiar with IC procedures. Education in IC in dental schools and in continuing training in hospitals, and mandatory regulations are needed to improve IC practices in dental health care settings.
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Affiliation(s)
- Jing Su
- Department of Nosocomial Infection Control, Capital Medical University School of Stomatology, Beijing, China
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15
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Abstract
Stenotrophomonas maltophilia is an emerging multidrug-resistant global opportunistic pathogen. The increasing incidence of nosocomial and community-acquired S. maltophilia infections is of particular concern for immunocompromised individuals, as this bacterial pathogen is associated with a significant fatality/case ratio. S. maltophilia is an environmental bacterium found in aqueous habitats, including plant rhizospheres, animals, foods, and water sources. Infections of S. maltophilia can occur in a range of organs and tissues; the organism is commonly found in respiratory tract infections. This review summarizes the current literature and presents S. maltophilia as an organism with various molecular mechanisms used for colonization and infection. S. maltophilia can be recovered from polymicrobial infections, most notably from the respiratory tract of cystic fibrosis patients, as a cocolonizer with Pseudomonas aeruginosa. Recent evidence of cell-cell communication between these pathogens has implications for the development of novel pharmacological therapies. Animal models of S. maltophilia infection have provided useful information about the type of host immune response induced by this opportunistic pathogen. Current and emerging treatments for patients infected with S. maltophilia are discussed.
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Affiliation(s)
- Joanna S Brooke
- Department of Biological Sciences, DePaul University, Chicago, Illinois, USA.
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O’Donnell MJ, Boyle MA, Russell RJ, Coleman DC. Management of dental unit waterline biofilms in the 21st century. Future Microbiol 2011; 6:1209-26. [DOI: 10.2217/fmb.11.104] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Dental chair units (DCUs) use water to cool and irrigate DCU-supplied instruments and tooth surfaces, and provide rinsewater during dental treatment. A complex network of interconnected plastic dental unit waterlines (DUWLs) supply water to these instruments. DUWLs are universally prone to microbial biofilm contamination seeded predominantly from microorganisms in supply water. Consequently, DUWL output water invariably becomes contaminated by high densities of microorganisms, principally Gram-negative environmental bacteria including Pseudomonas aeruginosa and Legionella species, but sometimes contain human-derived pathogens such as Staphylococcus aureus. Patients and staff are exposed to microorganisms from DUWL output water and to contaminated aerosols generated by DCU instruments. A wide variety of approaches, many unsuccessful, have been proposed to control DUWL biofilm. More recently, advances in biofilm science, chemical DUWL biofilm treatment agents, DCU design, supply water treatment and development of automated DUWL biofilm control systems have provided effective long-term solutions to DUWL biofilm control.
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Affiliation(s)
- Mary J O’Donnell
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin 2, Republic of Ireland
| | - Maria A Boyle
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin 2, Republic of Ireland
| | - Ronnie J Russell
- The Department of Microbiology, The Moyne Institute of Preventive Medicine, University of Dublin, Trinity College Dublin, Dublin 2, Republic of Ireland
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Boyle M, O’Donnell M, Russell R, Coleman D. Lack of cytotoxicity by Trustwater Ecasol™ used to maintain good quality dental unit waterline output water in keratinocyte monolayer and reconstituted human oral epithelial tissue models. J Dent 2010; 38:930-40. [DOI: 10.1016/j.jdent.2010.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 08/05/2010] [Accepted: 08/06/2010] [Indexed: 11/16/2022] Open
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Coleman DC, O'Donnell MJ, Boyle M, Russell R. Microbial biofilm control within the dental clinic: reducing multiple risks. J Infect Prev 2010. [DOI: 10.1177/1757177410376845] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This short review focuses on biofilms in the dental clinic environment. Microbial biofilms are potentially a significant source of cross-contamination and cross-infection in the dental clinic. Biofilms in dental chair unit waterlines (DUWLs), suction hoses and fittings pose the most significant risk as these may come into contact with the patient during treatment. These can be managed effectively by regular disinfection using chemical disinfectants and procedures that have proven efficacy. As dental chair units (DCUs) are classified as medical devices, there is a requirement for DCU manufacturers to provide detailed guidance for their decontamination. Planned routine preventive maintenance of the dental clinic water network and good quality water will considerably minimise infection risks from microorganisms in tap water and has benefits for the operation of other clinic equipment. Regular and effective cleaning and disinfection of taps, sinks and splash-backs will help to minimise reservoirs and disseminators of potentially pathogenic bacteria from these areas.
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Affiliation(s)
- David C Coleman
- Dublin Dental School and Hospital, Trinity College Dublin, Lincoln Place, Dublin, Ireland,
| | - Mary J O'Donnell
- Dublin Dental School and Hospital, Trinity College Dublin, Lincoln Place, Dublin, Ireland
| | - Maria Boyle
- Dublin Dental School and Hospital, Trinity College Dublin, Lincoln Place, Dublin, Ireland
| | - Ronnie Russell
- Department of Microbiology, Trinity College Dublin, Dublin, Ireland
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O’Donnell M, Boyle M, Swan J, Russell R, Coleman D. A centralised, automated dental hospital water quality and biofilm management system using neutral Ecasol™ maintains dental unit waterline output at better than potable quality: A 2-year longitudinal study. J Dent 2009; 37:748-62. [DOI: 10.1016/j.jdent.2009.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 06/02/2009] [Accepted: 06/03/2009] [Indexed: 10/20/2022] Open
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Coleman DC, O'Donnell MJ, Shore AC, Russell RJ. Biofilm problems in dental unit water systems and its practical control. J Appl Microbiol 2009; 106:1424-37. [PMID: 19187140 DOI: 10.1111/j.1365-2672.2008.04100.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland.
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21
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Sacchetti R, De Luca G, Zanetti F. Control of Pseudomonas aeruginosa and Stenotrophomonas maltophilia contamination of microfiltered water dispensers with peracetic acid and hydrogen peroxide. Int J Food Microbiol 2009; 132:162-6. [PMID: 19439386 DOI: 10.1016/j.ijfoodmicro.2009.04.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 04/20/2009] [Accepted: 04/21/2009] [Indexed: 11/16/2022]
Abstract
The abilities of peracetic acid and hydrogen peroxide to remove or reduce Pseudomonas aeruginosa and Stenotrophomonas maltophilia in output water from microfiltered water dispensers (MWDs) were investigated. Two MWDs were inoculated with strains of P. aeruginosa and S. maltophilia isolated from water. Dispensers A and B were disinfected with 10% (v/v) peracetic acid (PAA) and 3% (v/v) hydrogen peroxide (HP) respectively. Each dispenser was disinfected three times at monthly intervals with contact times of 10, 30 and 40 min. Water dispensed by the MWDs was collected immediately before and after each treatment and then twice weekly for the remaining period. Once a week a sample of the tap water entering the dispensers was tested. P. aeruginosa and S. maltophilia were enumerated in the 90 samples collected during 6 months. In the output water from the dispensers before the first treatment, the number of the bacteria was 3 to 4 log cfu/100 mL. Treatment with PAA greatly reduced the numbers of P. aeruginosa and S. maltophilia in the dispensed water initially. However, by 2 days after treatment, the numbers increased and remained high. In the case of disinfection with HP for 40 min, P. aeruginosa was not detected in most of the samples (73.7%). Numbers of S. maltophilia decreased with increasing time after treatment.
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Affiliation(s)
- Rossella Sacchetti
- Department of Medicine and Public Health, Division of Hygiene, University of Bologna, Via S. Giacomo, 12-40126 Bologna, Italy.
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Zanetti F, De Luca G, Sacchetti R. Control of bacterial contamination in microfiltered water dispensers (MWDs) by disinfection. Int J Food Microbiol 2009; 128:446-52. [DOI: 10.1016/j.ijfoodmicro.2008.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 09/18/2008] [Accepted: 10/04/2008] [Indexed: 11/26/2022]
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Coleman DC, O'Donnell MJ, Shore AC, Swan J, Russell RJ. The role of manufacturers in reducing biofilms in dental chair waterlines. J Dent 2007; 35:701-11. [PMID: 17576035 DOI: 10.1016/j.jdent.2007.05.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 05/03/2007] [Accepted: 05/08/2007] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVES This paper reviews how dental chair unit (DCU) manufacturers can contribute practically to resolving the problem of biofilm formation in dental unit waterlines (DUWs). STUDY SELECTION The review concentrates on how novel developments and changes in a range of specific areas have, and might contribute to DUW biofilm control. These include (i) DCU engineering and design changes; (ii) improvements to DCU supply water quality; (iii) development of automated DUW treatment procedures that are effective at controlling biofilm in the long-term, safe for patients and dental staff, environmentally friendly and which do not exhibit adverse effects on DCU components after prolonged use. SOURCES The majority of the material contained in this review is based on, or supported by the peer-reviewed literature. DATA The current consensus from the literature reveals that the emphasis on DUW biofilm and its control has focused on describing the problem and its control using a range of periodic and residual DUW treatment agents. Unfortunately, until recently, DCU manufacturers have provided very little specific guidance in this regard. Indeed, ensuring that DCUs provide good quality output water has generally been regarded to be the responsibility of dental practitioners. Some recent studies have shown that novel DCUs with integral semi-automated or automated DUW cleaning systems can effectively control DUW biofilm in the long-term. However, there are other potential DCU engineering and design changes that DCU manufacturers could undertake to further improve DUW biofilm control. CONCLUSIONS DCU manufacturers can significantly contribute to controlling the problem of DUW biofilm.
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Affiliation(s)
- D C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland.
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Walker JT, Marsh PD. Microbial biofilm formation in DUWS and their control using disinfectants. J Dent 2007; 35:721-30. [PMID: 17714847 DOI: 10.1016/j.jdent.2007.07.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 07/03/2007] [Accepted: 07/03/2007] [Indexed: 01/10/2023] Open
Abstract
OBJECTIVES Due to the presence of extended narrow bore tubing and long periods of stagnation, dental unit water systems (DUWs) can be prone to relatively high levels of microbial contamination, including the formation of biofilm and the presence of opportunistic pathogens, irrespective of the source and quality of the inflowing water. Whilst the European Union (EU) has yet to set a definitive microbiological guideline, the American Dental Association (ADA) has set a maximum of <200 colony forming units (cfu)/ml for DUWs water in the USA. The objective of this review is to discuss why microbial contamination and biofilms are so prevalent in DUWs, as well as the role of disinfectants and their potential for achieving microbial water quality levels recommended by the ADA. STUDY SELECTION The review outlines the principal factors responsible for biofilm formation in DUWs and a number of mechanisms used for microbial control. SOURCES The source material contained in this review is taken from the peer-reviewed literature. DATA A variety of disinfectants are available for use, but controlled laboratory and clinical studies have shown that they can vary markedly in their efficacy and suitability for use. Some products have been shown to successfully remove biofilm and consistently reduce the microbial load of out-flowing water to <200 cfu/ml. CONCLUSIONS The effective delivery of approved disinfectants can control the level of microorganisms in DUWs at acceptable levels.
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Affiliation(s)
- J T Walker
- Centre for Emergency Preparedness and Response, HPA Porton Down, Salisbury, United Kingdom
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25
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O'Donnell MJ, Shore AC, Russell RJ, Coleman DC. Optimisation of the long-term efficacy of dental chair waterline disinfection by the identification and rectification of factors associated with waterline disinfection failure. J Dent 2007; 35:438-51. [PMID: 17303302 DOI: 10.1016/j.jdent.2007.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 12/22/2006] [Accepted: 01/03/2007] [Indexed: 11/18/2022] Open
Abstract
UNLABELLED Although many studies have highlighted the problem of biofilm growth in dental chair unit waterlines (DUWs), no long-term studies on the efficacy of DUW disinfection using a large number of dental chair units (DCUs) have been reported. OBJECTIVES To investigate the long-term (21 months) efficacy of the Planmeca Waterline Cleaning System (WCS) to maintain the quality of DUW output water below the American Dental Association (ADA) recommended standard of < or =200cfu/mL of aerobic heterotrophic bacteria using once weekly disinfection with the hydrogen peroxide-and silver ion-containing disinfectant Planosil. METHODS Microbiological quality of DUW output water was monitored by culture on R2A agar for 10 DCUs fitted with the WCS. The presence of biofilm in DUWs was examined by electron microscopy. RESULTS During the first 9 months a high prevalence (28/300 disinfection cycles; 9.3%) of intermittent DUW disinfection failure occurred in 8/10 DCUs due to operator omission to disinfect all DUWs (10/28 failed cycles), incorrect compressed air pressure failing to distribute the disinfectant properly (4/28 failed cycles) and physical blockage of disinfectant intake valves due to corrosion effects of Planosil (14/28 failed cycles). On rectification of these faults through engineering redesign and procedural changes, no further cases of intermittent DUW disinfection failure were observed. Independently of these factors, a rapid and consistent decline in efficacy of DUW disinfection occurred in 4/10 DCUs following the initial 9 months of once weekly disinfection. There was a highly significant difference (P<0.0001) in the prevalence of strongly catalase-positive Novosphingobium and Sphingomonas bacterial species (mean average prevalence of 37.1%) in DUW output water from these 4 DCUs compared to the other 6 DCUs and DCU supply water (prevalence <1%), which correlated with biofilm presence in the DUWs and indicated selective pressure for maintenance of these species by prolonged disinfectant usage. Planosil was reformulated to a more concentrated form (Planosil Forte) and when used once weekly was found to maintain bacterial density in output water below the ADA standard for all 10 DCUs. CONCLUSIONS A variety of factors can contribute to failure of DUW disinfection in the long-term, including human error, disinfectant corrosion of equipment and natural selection of naturally disinfectant-tolerant bacterial species.
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Affiliation(s)
- M J O'Donnell
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Lincoln Place, Dublin 2, Ireland
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