Isolation of sulfate reducing bacteria from dental unit waterlines

Abstract number: R2416

Dogruoz N., Ilhan-sungur E., Goksay D., Türetgen I., Cotuk A.

Objectives: Dental Unit Waterlines (DUWLs) include a high number of long pipes with small diameter. Direct contact with municipal water, stagnant water, average temperature in DUWLs support the formation of microbial biofilms. Thus dental units might be contaminated by high levels of microorganisms. Aerobic, opportunist microorganisms such as Legionella pneumophila and also anaerobic sulphate reducing bacteria (SRB) may be present in biofilm. SRB reduce sulfur compounds to hydrogen sulfide (H2S) that is toxic and acidic product. H2S can cause corrosion, which leads to industrial loss, on metallic surfaces such as galvanised steel, stainless steel. In addition, H2S causes ulcerative colitis in human and, SRB trigger liver abscess and septicaemia. There is not any worldwide standard that have been devote to number of anaerobic SRB in DUWLs.

Methods: The aim of the present study was to determine the SRB distributions within different DUWLs. Water samples were taken from air-water syringe, high-speed drill and water source in 41 DUWLs. Most probable number technique and Posgate B medium were used for isolation and count of SRB.

Results: SRB were not determined in 21 (51%) inlet water source samples. However, SRB were recovered from all outlets of the DUWLs. While the highest determinable number of SRB in air-water syringe was 103 cells/ml, the lowest detectable count was 5 cells/ml. Also maximum concentration value of SRB in high-speed drill was established as106 cells/ml, minimum viable counts were 5 cells/ml.

Conclusion: We think that the presence of SRB in DUWLs may be undesirable since they can cause corrosion on metalic apparatus used in dentistry and also health problems in human gastrointestinal system.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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