Dental units: an environmental study of sources of potentially pathogenic mycobacteria

Schulze-Röbbecke, Roland; Feldmann, Claus; Fischeder, R.; Janning, B.; Exner, M.; Wahl, Gerhard

doi:10.1016/s0962-8479(05)80030-9

Cited by 107 publications

(65 citation statements)

References 19 publications

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“…in ca. 5% of surgeries, a lower detection rate than that reported by a previous study (30). These isolates were not identified, so their pathogenic potential is unknown, although several non-Mycobacterium tuberculosis, non-Mycobacterium avium species of mycobacteria are associated with a variety of infections in humans (18).…”

Section: Discussionmentioning

confidence: 96%

“…and opportunistic and true human pathogens (e.g., Pseudomonas aeruginosa, Legionella pneumophila, Mycobacterium spp., and Staphylococcus spp.) (10,14,16,21,30). Such organisms may originate from incoming local water supplies, although organisms commonly found in the oral cavity have also been recovered (37,38), suggesting that some bacteria may be derived from the patient following back siphonage.…”

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confidence: 99%

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Microbial Biofilm Formation and Contamination of Dental-Unit Water Systems in General Dental Practice

Walker

Bradshaw

Bennett

et al. 2000

Appl Environ Microbiol

198

166

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Dental-unit water systems (DUWS) harbor bacterial biofilms, which may serve as a haven for pathogens. The aim of this study was to investigate the microbial load of water from DUWS in general dental practices and the biofouling of DUWS tubing. Water and tube samples were taken from 55 dental surgeries in southwestern England. Contamination was determined by viable counts on environmentally selective, clinically selective, and pathogen-selective media, and biofouling was determined by using microscopic and image analysis techniques. Microbial loading ranged from 500 to 10 5 CFU ⅐ ml ؊1; in 95% of DUWS water samples, it exceeded European Union drinking water guidelines and in 83% it exceeded American Dental Association DUWS standards. Among visible bacteria, 68% were viable by BacLight staining, but only 5% of this "viable by BacLight" fraction produced colonies on agar plates. Legionella pneumophila, Mycobacterium spp., Candida spp., and Pseudomonas spp. were detected in one, five, two, and nine different surgeries, respectively. Presumptive oral streptococci and Fusobacterium spp. were detected in four and one surgeries, respectively, suggesting back siphonage and failure of antiretraction devices. Hepatitis B virus was never detected. Decontamination strategies (5 of 55 surgeries) significantly reduced biofilm coverage but significantly increased microbial numbers in the water phase (in both cases, P < 0.05). Microbial loads were not significantly different in DUWS fed with soft, hard, deionized, or distilled water or in different DUWS (main, tank, or bottle fed). Microbiologically, no DUWS can be considered "cleaner" than others. DUWS deliver water to patients with microbial levels exceeding those considered safe for drinking water.

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Section: Discussionmentioning

confidence: 96%

mentioning

confidence: 99%

Microbial Biofilm Formation and Contamination of Dental-Unit Water Systems in General Dental Practice

Walker

Bradshaw

Bennett

et al. 2000

Appl Environ Microbiol

198

166

View full text Add to dashboard Cite

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“…Furthermore, non-tuberculosis Mycobacterium species [41,47], Klebsiella pneumoniae [37,57], P. aeruginosa [16,26] and S. marcescens [30,44,57] have also been identified. Despite tight controls to make sure the treatment water is safe, an elderly patient died from legionellosis following dental treatment in which L. pneumophila serogroup I was identified using molecular profiling from isolates taken both from the patient and from the clinical environment of the dental practice where treatment was performed, confirming the source of infection [43].…”

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confidence: 99%

Risk Assessment for the Spread of Serratia marcescens Within Dental-Unit Waterline Systems Using Vermamoeba vermiformis

et al. 2015

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(2015) Risk assessment for the spread of Serratia marcescens within dental unit waterline systems using Vermamoeba vermiformis. Current Microbiology, 71 (4). pp. 434 442.It is advisable to refer to the publisher's version if you intend to cite from the work.http://dx.doi.org/10.1007/s00284-015-0872-0For more information about UCLan's research in this area go to http://www.uclan.ac.uk/researchgroups/ and search for . Conflict of interest disclosure statementAll named authors declare that there is no conflict of interest.2 Title: Risk assessment for the spread of Serratia marcescens within dental-unit waterline systems using Vermamoeba vermiformis Abstract:Vermamoeba vermiformis is associated with the biofilm ecology of dental-unit waterlines (DUWLs). This study investigated whether V. vermiformis is able to act as a vector for potentially pathogenic bacteria and so aid their dispersal within DUWL systems. Clinical dental water was initially examined for Legionella species by inoculating it onto Legionella selective-medium plates. The molecular identity/profile of the glassy colonies obtained indicated none of these isolates were Legionella species. During this work bacterial colonies were identified as a non-pigmented Serratia marcescens. As the water was from a clinical DUWL which had been treated with Alpron™ this prompted the question as to whether S. marcescens had developed resistance to the biocide. Exposure to Alpron™ indicated that this dental biocide was effective, under laboratory conditions, against S. marcescens at up to 1x10 8 colony forming units/millilitre (cfu/ml). V. vermiformis was cultured for eight weeks on cells of S. marcescens and Escherichia coli. Subsequent electron microscopy showed that V.vermiformis grew equally well on S. marcescens and E. coli (p = 0.0001). Failure to detect the presence of S.marcescens within the encysted amoebae suggests that V. vermiformis is unlikely to act as a vector supporting the growth of this newly isolated, nosocomial bacterium.

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“…The glycopeptidolipids present in the outermost layer of the cell walls of mycobacteria play an important role in surface colonization and biofilm formation (3,7,10). The biofilms represent an important risk of contamination for water distribution systems (8,9,12,13). Lately, a nosocomial outbreak of vertebral osteomyelitis due to Mycobacterium xenopi (5) has been reported by a French surgical center (2).…”

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confidence: 99%

Mycobacterium xenopi and Drinking Water Biofilms

Dailloux

Albert

Laurain

et al. 2003

Appl Environ Microbiol

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The ability of Mycobacterium xenopi to colonize an experimental drinking water distribution system (a Propella reactor) was investigated. M. xenopi was present in the biofilm within an hour following its introduction. After 9 weeks, it was always present in the outlet water (1 to 10 CFU 100 ml ؊1 ) and inside the biofilm (10 2 to 10 3 CFU cm ؊2 ). Biofilms may be considered reservoirs for the survival of M. xenopi.Mycobacteria have no usual adherence factors such as pili, fimbriae, and slime, but the hydrophobic properties of the cell wall appear to contribute to the adherence process. The glycopeptidolipids present in the outermost layer of the cell walls of mycobacteria play an important role in surface colonization and biofilm formation (3,7,10). The biofilms represent an important risk of contamination for water distribution systems (8,9,12,13). Lately, a nosocomial outbreak of vertebral osteomyelitis due to Mycobacterium xenopi (5) has been reported by a French surgical center (2). These infections were associated with invasive medical procedures and related to the presence of M. xenopi in the tap water distribution network. However, the role of M. xenopi in the biofilm formation process has not yet been investigated. The aim of this study was to evaluate the ability of M. xenopi to colonize an experimental water supply system.A model biofilm reactor, the Propella reactor (with a distribution pipe 90 mm in diameter and 500 mm long), was used to simulate a drinking water distribution system (1). The inner surface of the pipe was covered with high-density polyethylene (HDPE), which is commonly used in drinking water pipes. The reactor had a volume of 2,080 ml and an HDPE pipe surface of 1,413 cm 2 . It was continuously supplied with tap water (from a local drinking water network) at a flow rate of 83.5 ml h Ϫ1 . The water velocity (0.2 m s Ϫ1 ) was controlled with a marine propeller, which pulsed the water through an inner pipe, giving a flux parallel to the pipe wall. The formation of a biofilm on the pipe wall and the concentration of embedded bacterial cells could be studied by using 20 coupons (1.7 cm 2 ) inserted into the inner surface of the pipe. A special device allowed the removal of the coupons without any flow interruption.M. xenopi (CIP 104035) was subcultured on LowensteinJensen medium at 40°C (optimal growth temperature). A suspension was prepared in sterile distilled water and centrifuged (4,300 ϫ g for 30 min at 20°C). The pellet was washed twice in sterile distilled water to limit carbon contamination from culture media and suspended in sterile distilled water. The suspension was calibrated to a density equivalent to a McFarland standard of 1 and serially diluted (10 Ϫ1 to 10 Ϫ9 ) in sterile distilled water; for the enumeration of mycobacteria, 0.2 ml of each dilution was plated on Lowenstein-Jensen medium (catalog no. 55246; Bio-Rad). Media were incubated at 40°C. Five weeks later, the colonies were counted.The investigation was performed in duplicate with two similar Propella reactors (A an...

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Dental units: an environmental study of sources of potentially pathogenic mycobacteria

Cited by 107 publications

References 19 publications

Microbial Biofilm Formation and Contamination of Dental-Unit Water Systems in General Dental Practice

Microbial Biofilm Formation and Contamination of Dental-Unit Water Systems in General Dental Practice

Risk Assessment for the Spread of Serratia marcescens Within Dental-Unit Waterline Systems Using Vermamoeba vermiformis

Mycobacterium xenopi and Drinking Water Biofilms

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