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Castellano Realpe OJ, Gutiérrez JC, Sierra DA, Pazmiño Martínez LA, Prado Palacios YY, Echeverría G, de Waard JH. Dental Unit Waterlines in Quito and Caracas Contaminated with Nontuberculous Mycobacteria: A Potential Health Risk in Dental Practice. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E2348. [PMID: 32244267 PMCID: PMC7177417 DOI: 10.3390/ijerph17072348] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/16/2020] [Accepted: 02/20/2020] [Indexed: 11/17/2022]
Abstract
Three cases of severe odontogenic infections due to nontuberculous mycobacteria (NTM) in Venezuela that were directly associated with dental procedures and the finding of dental unit waterlines (DUWLs) in dental offices that were colonized with mycobacteria species was the reason for assessing the water quality of DUWLs in dental offices in two capital cities in South America, namely, Quito and Caracas. The main water supplies and the water from 143 DUWLs in both cities were sampled and especially checked for contamination with NTM. To measure the overall bacteriological quality of the water also the presence of heterotrophic bacteria, coliform bacteria, and Pseudomonas was determined. Results showed that respectively 3% and 56% of the DUWLs in Quito and Caracas yielded NTM species (up to 1000 colony-forming units (CFU)/mL). Furthermore, high and unacceptable total viable counts of heterotrophic bacteria and/or coliform bacteria and Pseudomonas were detected in 73% of the samples. We conclude that, in both cities, the water in the majority of DUWLs was contaminated with NTM and other potential pathogens, presenting a risk to human health. The detection of NTM in DUWL water with acceptable heterotrophic bacteria counts shows the need to include NTM in water quality testing. Mycobacteria are more resistant to disinfection procedures than other types of vegetative bacteria, and most testing protocols for DUWLs do not assess mycobacteria and thus do not guarantee risk-free water.
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Affiliation(s)
| | - Johanna C. Gutiérrez
- Facultad de Medicina. Escuela de Bioanálisis, Universidad Central de Venezuela, 1053 Caracas, Venezuela
- Instituto de Biomedicina “Dr. Jacinto Convit”, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | - Deisy A. Sierra
- Facultad de Medicina. Escuela de Bioanálisis, Universidad Central de Venezuela, 1053 Caracas, Venezuela
- Instituto de Biomedicina “Dr. Jacinto Convit”, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | | | - Yrneh Y. Prado Palacios
- Instituto de Biomedicina “Dr. Jacinto Convit”, Universidad Central de Venezuela, 1010 Caracas, Venezuela
| | - Gustavo Echeverría
- Instituto de Investigación en Salud Pública y Zoonosis CIZ, Universidad Central del Ecuador, 170521 Quito, Ecuador
| | - Jacobus H. de Waard
- Instituto de Biomedicina “Dr. Jacinto Convit”, Universidad Central de Venezuela, 1010 Caracas, Venezuela
- One Health Research Group, Facultad de Ciencias de la Salud, Universidad De Las Américas, 170504 Quito, Ecuador
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Yoon HY, Lee SY. Establishing a laboratory model of dental unit waterlines bacterial biofilms using a CDC biofilm reactor. BIOFOULING 2017; 33:917-926. [PMID: 29160100 DOI: 10.1080/08927014.2017.1391950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/06/2017] [Indexed: 06/07/2023]
Abstract
In this study, a laboratory model to reproduce dental unit waterline (DUWL) biofilms was developed using a CDC biofilm reactor (CBR). Bacteria obtained from DUWLs were filtered and cultured in Reasoner's 2A (R2A) for 10 days, and were subsequently stored at -70°C. This stock was cultivated on R2A in batch mode. After culturing for five days, the bacteria were inoculated into the CBR. Biofilms were grown on polyurethane tubing for four days. Biofilm accumulation and thickness was 1.3 × 105 CFU cm-2 and 10-14 μm respectively, after four days. Bacteria in the biofilms included cocci and rods of short and medium lengths. In addition, 38 bacterial genera were detected in biofilms. In this study, the suitability and reproducibility of the CBR model for DUWL biofilm formation were demonstrated. The model provides a foundation for the development of bacterial control methods for DUWLs.
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Affiliation(s)
- Hye Young Yoon
- a Department of Oral Microbiology, College of Dentistry, Research Institute of Oral Science , Gangneung-Wonju National University , Gangneung , Korea
| | - Si Young Lee
- a Department of Oral Microbiology, College of Dentistry, Research Institute of Oral Science , Gangneung-Wonju National University , Gangneung , Korea
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Lal S, Singhrao SK, Achilles-Day UEM, Morton LHG, Pearce M, Crean S. Risk Assessment for the Spread of Serratia marcescens Within Dental-Unit Waterline Systems Using Vermamoeba vermiformis. Curr Microbiol 2015; 71:434-42. [DOI: 10.1007/s00284-015-0872-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/03/2015] [Indexed: 01/21/2023]
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Flores-Moreno K, Celis-Meneses JS, Meneses-Ruiz DM, Castillo-Rodal AI, Orduña P, Montiel BA, López-Vidal Y. Potential cross-reactivity of monoclonal antibodies against clinically relevant mycobacteria. Clin Exp Immunol 2014; 177:454-63. [PMID: 24580144 DOI: 10.1111/cei.12309] [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] [Accepted: 02/21/2014] [Indexed: 12/31/2022] Open
Abstract
Tuberculosis is a disease caused by the Mycobacterium tuberculosis complex (MTb). In 2011, global mortality due to tuberculosis was 1·4 million individuals. The only available vaccine is the attenuated M. bovis [bacillus Calmette-Guérin (BCG)] strain, which confers variable protection against pulmonary tuberculosis. Some widely distributed non-tuberculous mycobacteria (NTM), such as M. avium and M. arupense, are also potential pathogens for humans. This work aimed to produce and characterize monoclonal antibodies against the M. bovis BCG Mexico strain of the MTb, M. avium subs. hominissuis and the M. arupense strain from NTM. Hybridomas were produced from splenocytes of BALB/c female mice immunized with radiation-inactivated mycobacteria, and the immunoglobulin (Ig)G2a antibody-producing clones with the highest antigenic recognition were selected. The selected clones, Mbv 2A10 for M. bovis BCG Mexico, Mav 3H1 for M. avium and Mar 2D10 for M. arupense, were used in further studies. Enzyme-linked immunosorbent assay (ELISA) and immune proteomics analyses characterized the clones as having the highest cross-reactivity with mycobacteria. Using mass spectrometry, a number of proteins recognized by the monoclonal antibody (mAb) clones were identified. These proteins had roles in metabolic processes, hypoxia, cell cycle and dormancy. In addition, a Clustal W and Immune Epitope Database (IEDB) in-silico analysis was performed in protein sequences that result in the conserved regions within probability epitopes that could be recognized for Mbv2A10 and Mav3H1 clones.
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Affiliation(s)
- K Flores-Moreno
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
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5
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Lal S, Singhrao SK, Bricknell M, Pearce M, Morton LHG, Ahmed W, Crean SJ. Monitoring Dental-Unit-Water-Line Output Water by Current In-office Test Kits. Curr Microbiol 2014; 69:135-42. [DOI: 10.1007/s00284-014-0569-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
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Garg SK, Mittal S, Kaur P. Dental unit waterline management: historical perspectives and current trends. ACTA ACUST UNITED AC 2012; 3:247-52. [DOI: 10.1111/j.2041-1626.2012.00135.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 02/19/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Shushant K. Garg
- Maharishi Markandeshwar College of Dental Sciences and Research; Mullana-Ambala Haryana India
| | - Sanjeev Mittal
- Maharishi Markandeshwar College of Dental Sciences and Research; Mullana-Ambala Haryana India
| | - Prabhmanik Kaur
- Maharishi Markandeshwar College of Dental Sciences and Research; Mullana-Ambala Haryana India
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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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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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Orrù G, Del Nero S, Tuveri E, Laura Ciusa M, Pilia F, Erriu M, Orrù G, Liciardi M, Piras V, Denotti G. Evaluation of antimicrobial-antibiofilm activity of a hydrogen peroxide decontaminating system used in dental unit water lines. Open Dent J 2010; 4:140-6. [PMID: 21113279 PMCID: PMC2948419 DOI: 10.2174/1874210601004010140] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 02/15/2010] [Accepted: 02/25/2010] [Indexed: 11/22/2022] Open
Abstract
A dental unit water line (DUWL) equipped with a device designed to automatically and continually flush a bacteriostatic solution of hydrogen peroxide (WHE) and a discontinuous disinfecting system (BIOSTER) was evaluated. In the first instance a preliminary sensitivity test on a large number of microorganisms (bacteria and fungi) was tried with a H2O2 range from 100 to 800 ppm. The bacteria frequently reported in DUWL (including Pseudomonas spp, Streptococcus spp., Staphylococcus spp., E. coli) and some periodontal pathogens showed a minimum inhibitory concentration from 100 to 300 H2O2 ppm (also including M. marinum and C. albicans). However, H2O2 did not show any inhibitory effects against: A. actinomycetemcomitans, C. glabrata C. parapsilos, F. nucleatum, M. micros. In a second step, the DUWL was experimentally infected with S. faecalis, E. coli, P. aeruginosa, S. aureus. After disinfection steps with 3% H2O2, the inhibitory effect on planktonic forms and on sessile biofilm was measured. In a third step, the count of 16S rRNA gene copies by real time PCR at different points of the DUWL described an accrue of bacterial slime in “hot spot” regions characterized by irregular/slow water flux (valves, elbows). However these results suggest that hydrogen peroxide is not only able to inhibit bursts of planktonic bacteria inside the DUWL, but that it could also be effective against sessile biofilm containing heterotrophic microorganisms derived from domestic water line contamination. In addition some oral pathogens could be contaminating and surviving in DUWL.
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Affiliation(s)
- Germano Orrù
- OBL (Oral Biotechnology Laboratory), Dipartimento di Chirurgia e Scienze Odontostomatologiche, Universita' degli Studi di Cagliari, Cagliari, Italy
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10
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Nontuberculous Mycobacteria and the Lung: From Suspicion to Treatment. Lung 2010; 188:269-82. [DOI: 10.1007/s00408-010-9240-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 03/19/2010] [Indexed: 10/19/2022]
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Abstract
It has become apparent that Mycobacterium mucogenicum isolates recovered from clinical samples are more diverse than was previously realized and include an increasing number of emerging pathogens, as depicted by multilocus sequence analysis. Most clinically significant cases of those organisms involved catheter-related infections. They are susceptible to most antimicrobial agents, but like other rapidly growing mycobacteria, they are resistant to first-line antituberculous agents. A review of the cases of M. mucogenicum complex infection in the literature is addressed here, as well as two additional cases of the closely related species Mycobacterium aubagnense.
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Affiliation(s)
- T Adékambi
- Division of Infectious Diseases, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA.
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12
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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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Dutil S, Meriaux A, de Latremoille MC, Lazure L, Barbeau J, Duchaine C. Measurement of airborne bacteria and endotoxin generated during dental cleaning. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2009; 6:121-130. [PMID: 19093289 DOI: 10.1080/15459620802633957] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Dynamic dental instruments generate abundant aerosols in the work environment. Dental unit waterlines (DUWL) support a large microbial population and can be a significant source of bioaerosols generated during dental treatments. This study was conducted to characterize bioaerosol generation during dental treatments performed in standardized conditions. Culture-based method (R2A, and blood agar with and without O2) and fluorescence microscopy were used. Dental cleaning procedures were performed in an isolated treatment room with controlled ventilation rate. Andersen microbial samplers were used to collect culturable bioaerosols generated before (baseline), during, and after 2 hr of dental treatments. Inhalable dust samplers were used to measure total bioaerosols content in dental hygienist's and patients' breathing zones. AGI-30 were used for the collection of the endotoxin. The use of fluorescence microscopy in combination with culture demonstrated that dental staff and patients were exposed to up to 1.86 E+05 bacteria/m(3) generated during treatments. Fortunately, bioaerosols returned to baseline within 2 hr after the dental procedures. The small diameter of the aerosols generated (< 1 microm) suggests that the risk of contact between the aerosolized bacteria and the respiratory system of exposed individuals is likely to occur.
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Affiliation(s)
- Steve Dutil
- Institut Universitaire de Cardiologie et de Pneumologie de l'Universite Laval, Hopital Laval, Quebec City, Quebec, Canada
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Pankhurst CL, Coulter WA. Do contaminated dental unit waterlines pose a risk of infection? J Dent 2007; 35:712-20. [PMID: 17689168 DOI: 10.1016/j.jdent.2007.06.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 06/01/2007] [Accepted: 06/05/2007] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES To review the evidence that the dental unit waterlines are a source of occupational and healthcare acquired infection in the dental surgery. DATA Transmission of infection from contaminated dental unit waterlines (DUWL) is by aerosol droplet inhalation or rarely imbibing or wound contamination in susceptible individuals. Most of the organisms isolated from DUWL are of low pathogenicity. However, data from a small number of studies described infection or colonisation in susceptible hosts with Legionella spp., Pseudomonas spp. and environmental mycobacteria isolated from DUWL. The reported prevalence of legionellae in DUWL varies widely from 0 to 68%. The risk from prolonged occupational exposure to legionellae has been evaluated. Earlier studies measuring surrogate evidence of exposure to legionellae in dental personnel found a significant increase in legionella antibody levels but in recent multicentre studies undertaken in primary dental care legionellae were isolated at very low rate and the corresponding serological titres were not above background levels. Whereas, a case of fatal Legionellosis in a dental surgeon concluded that the DUWL was the likely source of the infection. The dominant species isolated from dental unit waterlines (DUWL) are Gram-negative bacteria, which are a potent source of cell wall endotoxin. A consequence of indoor endotoxin exposure is the triggering or exacerbation of asthma. Data from a single large practice-based cross-sectional study reported a temporal association between occupational exposure to contaminated DUWL with aerobic counts of >200cfu/mL at 37 degrees C and development of asthma in the sub-group of dentists in whom asthma arose following the commencement of dental training. SOURCES Medline 1966 to February 2007 was used to identify studies for this paper. STUDY SELECTION Design criteria included randomised control trials, cohort, and observational studies in English. CONCLUSIONS Although the number of published cases of infection or respiratory symptoms resulting from exposure to water from contaminated DUWL is limited, there is a medico-legal requirement to comply with potable water standards and to conform to public perceptions on water safety.
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Affiliation(s)
- Caroline L Pankhurst
- Department of Oral Medicine, King's College London Dental Institute, Bessemer Road, London, United Kingdom.
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Adékambi T, Foucault C, La Scola B, Drancourt M. Report of two fatal cases of Mycobacterium mucogenicum central nervous system infection in immunocompetent patients. J Clin Microbiol 2006; 44:837-40. [PMID: 16517863 PMCID: PMC1393080 DOI: 10.1128/jcm.44.3.837-840.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neurological infections due to rapidly growing mycobacteria (RGM) have rarely been reported. We recently investigated two unrelated immunocompetent patients, one with community-acquired lymphocytic meningitis and the other with cerebral thrombophlebitis. Mycobacterium mucogenicum was isolated in pure culture and detected by PCR sequencing of cerebrospinal fluid samples. Both patients eventually died. The two isolates exhibited an overlapping antimicrobial susceptibility pattern. They were susceptible in vitro to tetracyclines, macrolides, quinolones, amikacin, imipenem, cefoxitin, and trimethoprim-sulfamethoxazole and resistant to ceftriaxone. They shared 100% 16S rRNA gene sequence similarity with M. mucogenicum ATCC 49650T over 1,482 bp. Their partial rpoB sequences shared 97.8% and 98.1% similarity with M. mucogenicum ATCC 49650T, suggesting that the two isolates were representative of two sequevars of M. mucogenicum species. This case report should make clinicians aware that M. mucogenicum, an RGM frequently isolated from tap water or from respiratory specimens and mostly without clinical significance, can even be encountered in the central nervous system of immunocompetent patients.
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Affiliation(s)
- Toïdi Adékambi
- Unité des Rickettsies, CNRS UMR 6020 IFR 48, Faculté de Médecine, Université de la Méditerranée, 27 Boulevard Jean Moulin, 13385 Marseille Cedex 05, France
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Abstract
There is growing interest in the use of ozone in oral healthcare and the National Institute for Clinical Excellence (NICE) is at present reviewing the evidence for its effectiveness in the management of occlusal and plain surface caries. These are only two of the clinical problems for which ozone can, and has, been used; it has also been employed for a wide variety of other purposes in both dentistry and medicine. This pale blue-coloured gas plays an important role as a natural constituent in the higher layer of the Earth's atmosphere. There is growing evidence that it can be employed as a useful therapeutic agent. This paper reviews its therapeutic uses to date and suggests its possible future clinical applications. Consumer demands for this strong oxidant may increase as the general public becomes increasingly aware of its therapeutic capacity and the non-invasive manner in which it can be administered.
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Affiliation(s)
- Aylin Baysan
- Department of Restorative Dentistry, GKT, King's College London, London SE1 9RT, UK.
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Vaerewijck MJM, Huys G, Palomino JC, Swings J, Portaels F. Mycobacteria in drinking water distribution systems: ecology and significance for human health. FEMS Microbiol Rev 2005; 29:911-34. [PMID: 16219512 DOI: 10.1016/j.femsre.2005.02.001] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2004] [Revised: 11/29/2004] [Accepted: 02/05/2005] [Indexed: 01/04/2023] Open
Abstract
In contrast to the notorious pathogens Mycobacterium tuberculosis and M. leprae, the majority of the mycobacterial species described to date are generally not considered as obligate human pathogens. The natural reservoirs of these non-primary pathogenic mycobacteria include aquatic and terrestrial environments. Under certain circumstances, e.g., skin lesions, pulmonary or immune dysfunctions and chronic diseases, these environmental mycobacteria (EM) may cause disease. EM such as M. avium, M. kansasii, and M. xenopi have frequently been isolated from drinking water and hospital water distribution systems. Biofilm formation, amoeba-associated lifestyle, and resistance to chlorine have been recognized as important factors that contribute to the survival, colonization and persistence of EM in water distribution systems. Although the presence of EM in tap water has been linked to nosocomial infections and pseudo-infections, it remains unclear if these EM provide a health risk for immunocompromised people, in particular AIDS patients. In this regard, control strategies based on maintenance of an effective disinfectant residual and low concentration of nutrients have been proposed to keep EM numbers to a minimum in water distribution systems.
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Affiliation(s)
- Mario J M Vaerewijck
- Laboratory of Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
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18
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Abstract
The molecular aetiology of familial susceptibility to disseminated mycobacterial disease, usually involving weakly pathogenic strains of mycobacteria, has now been elucidated in more than 30 families. Mutations have been identified in five genes in the interleukin-12-dependent interferon-gamma pathway, highlighting the importance of this pathway in human mycobacterial immunity. Knowledge derived from the study of these rare patients contributes to our understanding of the immune response to common mycobacterial pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, which remain major public health problems globally. This knowledge can be applied to the rational development of novel therapies and vaccines for these important mycobacterial diseases.
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Affiliation(s)
- Melanie Newport
- Cambridge Institute for Medical Research, Addenbrookes Hospital, Hills Road, Cambridge, CB2 2XY, UK.
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