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Özmen P, Erdoğan H, Güngördü A, Pişkin B, Çobankara FK, Sütcü S, Şahin N. Comparison of antimicrobial efficacy of different disinfectants on the biofilm formation in dental unit water systems using dip slide and conventional methods: A pilot study. Microsc Res Tech 2024; 87:1241-1249. [PMID: 38328888 DOI: 10.1002/jemt.24511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 10/07/2023] [Accepted: 01/25/2024] [Indexed: 02/09/2024]
Abstract
OBJECTIVE Biofilm formation in dental waterlines brings opportunistic infections, especially for immunosuppressive patients. This study aimed to determine biofilm-forming microorganisms by various methods and investigate disinfectants' effects on biofilm. MATERIALS & METHODS In the study, samples were obtained from the waterlines of 10-15 aged six dental units, before (0 min.) and after chlorine dioxide (ClO2) and hypochlorous acid (HOCl) treatment (1, 5, 10, 20, and 30 min.), and total colony counts were performed using conventional surface smear method (SSM) and dip slide method (DSM). The Congo red agar and Christensen methods were used to examine the biofilm-forming properties of the isolates. Monitoring of biofilm presence was also visualized by SEM scanning. RESULTS When DSM and SSM are compared in all units where ClO2 and HOCl are applied, DSM can detect bacterial growth even during periods of greater exposure to disinfectant application. Although DSM can achieve a value approaching 3% even at the 10th minute in units treated with HOCl; SSM does not show reproduction at the same disinfectant exposure and duration; It was observed that in the units where ClO2 was applied, the growth was no longer observed at the 10th minute with DSM, and SSM, 50% growth in the first minute of the units treated with ClO2 could not be detected in the 5th minute. CONCLUSIONS It is concluded that it can be advisable to routinely disinfect the dental unit water systems with non-toxic doses of ClO2 application before patient treatments in clinics and also to perform contamination controls at regular intervals with DSM, which is a sensitive and very practical method. RESEARCH HIGHLIGHTS It has been observed that the dip slide method can count bacteria more sensitively than conventional methods in dental water systems without the need for experienced personnel and equipment. The difference between biofilm formation in water systems before and after disinfectant exposure in SEM examinations is remarkable. The effects of ClO2 and HOCl on biofilm were investigated and bacterial growth was inhibited in dental units between 5 and 10 minutes with both disinfectants.
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Affiliation(s)
- Pelin Özmen
- Department of Medical Microbiology, Faculty of Dentistry, Nevşehir Hacı Bektas Veli University, Nevsehir, Turkey
| | - Hilal Erdoğan
- Department of Endodontics, Faculty of Dentistry, Nevsehir Haci Bektas Veli University, Nevsehir, Turkey
| | - Aslıhan Güngördü
- Department of Endodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey
| | - Bülent Pişkin
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cappadocia University, Nevsehir, Turkey
| | - Funda Kont Çobankara
- Department of Endodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey
| | - Serdar Sütcü
- Department of Periodontology, Faculty of Dentistry, Cappadocia University, Nevsehir, Turkey
| | - Nesrin Şahin
- Department of Prosthetic Dentistry, Faculty of Dentistry, Cappadocia University, Nevsehir, Turkey
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Fang Z, Zhou X, Liao H, Xu H. A meta-analysis of Legionella pneumophila contamination in hospital water systems. Am J Infect Control 2023; 51:1250-1262. [PMID: 37054892 DOI: 10.1016/j.ajic.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/31/2023] [Accepted: 04/01/2023] [Indexed: 04/15/2023]
Abstract
BACKGROUND Legionella pneumophila is a common cause of community-acquired pneumonia. We aimed to determine the pooled rates of L pneumophila contamination in the water environment of the hospital. METHODS We searched PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure, WangFang and Science Direct, The Cochrane Library, and Science Finder, for relevant studies published until December 2022. Stata 16.0 software was used to determine pooled contamination rates, publication bias, and subgroup analysis. RESULTS Forty-eight eligible articles with a total of 23,640 samples of water were evaluated, and the prevalence of L pneumophila was 41.6%. The results of the subgroup analysis showed that the pollution rate of L pneumophila in hot water (47.6%) was higher than that in other water bodies. The rates of L pneumophila contamination were higher in developed countries (45.2%), culture methods (42.3%), published between 1985 and 2015 (42.9%), and studies with a sample size of less than 100 (53.0%). CONCLUSIONS L pneumophila contamination in medical institutions is still very serious and should be paid attention to, especially in developed countries and hot water tanks.
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Affiliation(s)
- Zisi Fang
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Xiaocong Zhou
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Hui Liao
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Hong Xu
- Department of Environmental Health, Hangzhou Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
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Optenhövel M, Mellmann A, Kuczius T. Occurrence and prevalence of Legionella species in dental chair units in Germany with a focus on risk factors. Eur J Clin Microbiol Infect Dis 2023; 42:1235-1244. [PMID: 37698817 PMCID: PMC10511595 DOI: 10.1007/s10096-023-04659-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/28/2023] [Indexed: 09/13/2023]
Abstract
PURPOSE Water-bearing instruments and treatments in dental units produce aerosols originating from the dental unit waterlines (DUWLs), which are often microbially contaminated. Particularly, the presence of Legionella mainly realized as aerosols leads to a risk of infection in patients and dental staff. METHODS Here, we record the general bacteriological status of DUWLs in Germany and investigated the prevalence of Legionella spp., with a focus on identification and occurrence of distinct species considering the various aspects of dental practice such as dental chair equipment, disinfection methods, and temperatures. RESULTS Out of 3789 water samples of 459 dental practices, collected in the years 2019 and 2020, 36.4% were Legionella positive with predominance of L. anisa (97.89%) identified by MALDI-TOF biotyping. L. pneumophila was detected very rarely. Risk factor analysis revealed that temperatures >20°C are a significant factor for increased Legionella colonization. CONCLUSION In order to minimize the risk of infection, routine monitoring of the water quality in dental chair units is recommended with regard to general microbiological loads and to the presence of Legionella as opportunistic pathogen as well as the regular application of routine disinfection procedures.
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Affiliation(s)
- Marleen Optenhövel
- Institute of Hygiene, University Hospital Münster, Robert Koch-Straße 41, 48149, Münster, Germany
| | - Alexander Mellmann
- Institute of Hygiene, University Hospital Münster, Robert Koch-Straße 41, 48149, Münster, Germany
| | - Thorsten Kuczius
- Institute of Hygiene, University Hospital Münster, Robert Koch-Straße 41, 48149, Münster, Germany.
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Gawish S, Abbass A, Abaza A. Occurrence and biofilm forming ability of Pseudomonas aeruginosa in the water output of dental unit waterlines in a dental center in Alexandria, Egypt. Germs 2019; 9:71-80. [PMID: 31341834 DOI: 10.18683/germs.2019.1160] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/13/2019] [Accepted: 05/23/2019] [Indexed: 11/08/2022]
Abstract
Introduction Dental unit waterlines (DUWLs) are notorious for being contaminated with different bacterial species including the opportunistic pathogen Pseudomonas aeruginosa which poses a risk to patients and professionals. This work aimed at studying the occurrence and biofilm-forming ability (BFA) of P. aeruginosa in the output of DUWLs in a dental center in Egypt. Methods Water samples were collected from the outlets of the high-speed hand piece, the air/water syringe and the cup filler waterlines. Bacteriological analysis included heterotrophic plate count (HPC), isolation and identification of P. aeruginosa and determination of the antimicrobial susceptibility and the BFA of the isolates by tissue culture plate (TCP) method and tube method (TM). Results The average concentration of HPC bacteria in the output of the 3 DUWLs was 2.9×104 CFU/μL where 88.3% of the samples exceeded the Egyptian standards for drinking water (<50 CFU L). P. aeruginosa was isolated from nine cup filler samples (which had a water source different from the other waterlines). The isolates were sensitive to all tested antimicrobials. Of these nine isolates, 6, 5 and 4 were positive for BFA by TCP, modified TCP and TM, respectively. Conclusions More stringent measures are required to ensure safer dental water; as the majority of studied samples exceeded the required HPC bacterial limit and P. aeruginosa isolates were detected. P. aeruginosa isolates from DUWLs may not be as resistant to antibiotics as what is reported in the literature about clinical isolates. Some P. aeruginosa isolates can colonize DUWLs despite their inability to form biofilms in experimental testing.
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Affiliation(s)
- Sheref Gawish
- MSc Microbiology, Microbiology Department, High Institute of Public Health, Alexandria University, 165 El Horreya Avenue, Alexandria, Egypt
| | - Aleya Abbass
- PhD, Professor of Microbiology, Microbiology Department, High Institute of Public Health, Alexandria University, 165 El Horreya Avenue, Alexandria, Egypt
| | - Amani Abaza
- PhD, Professor of Microbiology, Microbiology Department, High Institute of Public Health, Alexandria University, 165 El Horreya Avenue, Alexandria, Egypt
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Petti S, Vitali M. Occupational risk for Legionella infection among dental healthcare workers: meta-analysis in occupational epidemiology. BMJ Open 2017; 7:e015374. [PMID: 28710211 PMCID: PMC5734417 DOI: 10.1136/bmjopen-2016-015374] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE The occupational risk for Legionella infection among dental healthcare workers (DHCWs) is conjectured because of the risk of routine inhalation of potentially contaminated aerosols produced by the dental instruments. Nevertheless, occupational epidemiology studies are contrasting. This meta-analysis assessed the level of scientific evidence regarding the relative occupational risk for Legionella infection among DHCWs. METHODS Literature search was performed without time and language restrictions, using broad data banks (PubMed, Scopus, Web of Science, GOOGLE Scholar) and generic keywords ('legionella' AND 'dent*'). Analytical cross-sectional studies comparing prevalence of high serum Legionella antibody levels in DHCWs and occupationally unexposed individuals were considered. The relative occupational risk was assessed through prevalence ratio (PR) with 95% CI. Between-study heterogeneity was assessed (Cochran's Q test) and was used to choose the meta-analytic method. Study quality (modified Newcastle-Ottawa Scale) and publication bias (Begg and Mazumdar's test, Egger and colleagues' test, trim and fill R0 method) were assessed formally and considered for the sensitivity analysis. Sensitivity analysis to study inclusion, subgroup analyses (dental staff categories; publication year, before vs after 1998, ie, 5 years after the release by the Centers for Disease Control and Prevention of the infection control guidelines in dental healthcare setting) were performed. RESULTS Seven studies were included (2232 DHCWs, 1172 occupationally unexposed individuals). No evidence of publication bias was detected. The pooled PR estimate was statistically non-significant at 95% level (1.7; 95% CI 0.8 to 3.2), study-quality adjustment did not change the PR considerably (PR, 1.5; 95% CI 0.5 to 4.1). PR was statistically significant before 1998 and no longer significant after 1998. Subgroup analysis according to DHCW categories was inconclusive. CONCLUSIONS There is no scientific evidence that DHCWs are at high occupational risk. The differences between former and recent studies could be due to different characteristics of municipal water systems and the infection control guideline dissemination.
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Affiliation(s)
- Stefano Petti
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Matteo Vitali
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
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van Heijnsbergen E, Schalk JAC, Euser SM, Brandsema PS, den Boer JW, de Roda Husman AM. Confirmed and Potential Sources of Legionella Reviewed. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4797-815. [PMID: 25774976 DOI: 10.1021/acs.est.5b00142] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Legionella bacteria are ubiquitous in natural matrices and man-made systems. However, it is not always clear if these reservoirs can act as source of infection resulting in cases of Legionnaires' disease. This review provides an overview of reservoirs of Legionella reported in the literature, other than drinking water distribution systems. Levels of evidence were developed to discriminate between potential and confirmed sources of Legionella. A total of 17 systems and matrices could be classified as confirmed sources of Legionella. Many other man-made systems or natural matrices were not classified as a confirmed source, since either no patients were linked to these reservoirs or the supporting evidence was weak. However, these systems or matrices could play an important role in the transmission of infectious Legionella bacteria; they might not yet be considered in source investigations, resulting in an underestimation of their importance. To optimize source investigations it is important to have knowledge about all the (potential) sources of Legionella. Further research is needed to unravel what the contribution is of each confirmed source, and possibly also potential sources, to the LD disease burden.
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Affiliation(s)
- Eri van Heijnsbergen
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Johanna A C Schalk
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Sjoerd M Euser
- ‡Regional Public Health Laboratory Kennemerland, Haarlem, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands
| | - Petra S Brandsema
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Jeroen W den Boer
- ‡Regional Public Health Laboratory Kennemerland, Haarlem, Boerhaavelaan 26, 2035 RC Haarlem, The Netherlands
| | - Ana Maria de Roda Husman
- †National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
- §Institute for Risk Assessment Sciences, Utrecht University, Yalelaan 2, 3584 CM Utrecht, The Netherlands
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Leoni E, Dallolio L, Stagni F, Sanna T, D'Alessandro G, Piana G. Impact of a risk management plan on Legionella contamination of dental unit water. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:2344-58. [PMID: 25711357 PMCID: PMC4377905 DOI: 10.3390/ijerph120302344] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/13/2015] [Indexed: 11/23/2022]
Abstract
The study aimed to assess the prevalence of Legionella spp. in dental unit waterlines of a dental clinic and to verify whether the microbiological parameters used as indicators of water quality were correlated with Legionella contamination. A risk management plan was subsequently implemented in the dental health care setting, in order to verify whether the adopted disinfection protocols were effective in preventing Legionella colonization. The water delivered from syringes and turbines of 63 dental units operating in a dental clinic, was monitored for counts of the heterotrophic bacteria P. aeruginosa and Legionella spp. (22 °C and 37 °C). At baseline, output water from dental units continuously treated with disinfection products was more compliant with the recommended standards than untreated and periodically treated water. However, continuous disinfection was still not able to prevent contamination by Legionella and P. aeruginosa. Legionella was isolated from 36.4%, 24.3% and 53.3% of samples from untreated, periodically and continuously treated waterlines, respectively. The standard microbiological parameters used as indicators of water quality proved to be unreliable as predictors of the presence of Legionella, whose source was identified as the tap water used to supply the dental units. The adoption of control measures, including the use of deionized water in supplying the dental unit waterlines and the application of a combined protocol of continuous and periodic disinfection, with different active products for the different devices, resulted in good control of Legionella contamination. The efficacy of the measures adopted was mainly linked to the strict adherence to the planned protocols, which placed particular stress on staff training and ongoing environmental monitoring.
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Affiliation(s)
- Erica Leoni
- Department of Biomedical and Neuromotor Sciences, Unit of Hygiene, Public Health and Medical Statistics, University of Bologna, via San Giacomo 12, 40126, Bologna, Italy.
| | - Laura Dallolio
- Department of Biomedical and Neuromotor Sciences, Unit of Hygiene, Public Health and Medical Statistics, University of Bologna, via San Giacomo 12, 40126, Bologna, Italy.
| | - Francesca Stagni
- Department of Biomedical and Neuromotor Sciences, Unit of Odontostomatological Sciences, University of Bologna, via San Vitale 59, 40125, Bologna, Italy.
| | - Tiziana Sanna
- Department of Biomedical and Neuromotor Sciences, School of Hygiene and Preventive Medicine, University of Bologna, via San Giacomo 12, 40126, Bologna, Italy.
| | - Giovanni D'Alessandro
- Department of Biomedical and Neuromotor Sciences, Unit of Odontostomatological Sciences, University of Bologna, via San Vitale 59, 40125, Bologna, Italy.
| | - Gabriela Piana
- Department of Biomedical and Neuromotor Sciences, Unit of Odontostomatological Sciences, University of Bologna, via San Vitale 59, 40125, Bologna, Italy.
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Effect of different disinfection protocols on microbial and biofilm contamination of dental unit waterlines in community dental practices. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:2064-76. [PMID: 24552789 PMCID: PMC3945585 DOI: 10.3390/ijerph110202064] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/20/2014] [Accepted: 01/28/2014] [Indexed: 11/17/2022]
Abstract
Output water from dental unit waterlines (DUWLs) may be a potential source of infection for both dental healthcare staff and patients. This study compared the efficacy of different disinfection methods with regard to the water quality and the presence of biofilm in DUWLs. Five dental units operating in a public dental health care setting were selected. The control dental unit had no disinfection system; two were disinfected intermittently with peracetic acid/hydrogen peroxide 0.26% and two underwent continuous disinfection with hydrogen peroxide/silver ions (0.02%) and stabilized chlorine dioxide (0.22%), respectively. After three months of applying the disinfection protocols, continuous disinfection systems were more effective than intermittent systems in reducing the microbial contamination of the water, allowing compliance with the CDC guidelines and the European Council regulatory thresholds for drinking water. P. aeruginosa, Legionella spp, sulphite-reducing Clostridium spores, S. aureus and β-haemolytic streptococci were also absent from units treated with continuous disinfection. The biofilm covering the DUWLs was more extensive, thicker and more friable in the intermittent disinfection dental units than in those with continuous disinfection. Overall, the findings showed that the products used for continuous disinfection of dental unit waterlines showed statistically better results than the intermittent treatment products under the study conditions.
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Szymańska J, Sitkowska J. Bacterial contamination of dental unit waterlines. ENVIRONMENTAL MONITORING AND ASSESSMENT 2013; 185:3603-3611. [PMID: 22899458 PMCID: PMC3613572 DOI: 10.1007/s10661-012-2812-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 07/25/2012] [Indexed: 06/01/2023]
Abstract
Safety of patients and dental personnel requires the appropriate microbiological water quality in dental units. During treatment, patients and dental workers are exposed both to direct contact with bacteria-contaminated water in the form of splatter and with contaminated water aerosol emitted during work by unit handpieces, including rotating and ultrasonic instruments. The aim of the study was to determine the qualitative and quantitative contamination of water in dental unit reservoirs with aerobic and facultative anaerobic bacteria. The study material included water sampled from 107 dental unit reservoirs located in dental surgeries of public health centres. Conventional microbiological methods were used to identify microorganisms. The study shows that the contamination of water in dental unit reservoirs with aerobic and facultative anaerobic bacteria is commonplace. The mean concentration of mesophile bacteria in dental unit reservoir water exceeded 1.1 × 10(5) cfu/ml. The prevailing species were Gram-negative bacteria of the families Burkholderiaceae, Pseudomonadaceae, Ralstoniaceae and Sphingomonadaceae. The most numerous bacteria were Ralstonia pickettii, constituting 49.33 % of all the identified aerobic and facultative anaerobic bacteria. Among Gram-positive rods, the most numerous were bacteria of the genus Brevibacterium (5.83 %), while the highest percentage shares (13.25 %) of all Gram-positive microorganisms were found for Actinomyces spp. The study confirms the necessity of regular monitoring of microbial contamination of dental unit waterlines (DUWL) and use of various water treatment procedures available to disinfect DWUL.
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Affiliation(s)
- Jolanta Szymańska
- Chair and Department of Paedodontics, Medical University, Karmelicka 7, 20-018 Lublin, Poland.
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