Microbial contamination of dental unit waterlines in Istanbul, Turkey

Abstract

The water used in dental unit waterlines (DUWLs) acts as a coolant for the high-speed equipment and as an irrigant during dental treatments. There are kind of water tanks. DUWLs provide a favorable environment for microbial biofilm and multiplation primarily due to the high surface in the tubing and the character of fluid dynamics in narrow, smooth-walled waterlines. Biofilms can harbour opportunist pathogens such as Legionella sp., Pseudomonas sp. Several studies have shown that DUWLs have high levels of microbial contamination. Presence of high level of microbial contamination is an important problem for dentists and dental patients who are immunocompromised. We collected water samples from DUWLs of 20 private dental offices. We have determined that only 2 (3.4%) out of 59 dental unit water samples were found to meet the standard (<200 CFU.ml(-1)) for DUWLs water quality by American Dental Association (ADA). Of the 59 water samples examined, 14 (24%) were positive for Pseudomonas sp. and 18 (30.5%) were positive for fungi. The most common 14 bacterial strains and seven fungi were isolated. Of bacterial strains, 57.1% were identified: Majority of the bacterial species isolated from our samples was identified as Pseudomonas fluorescens, Pasteurella haemolytica, Photobacterium damsela, Ochrobacter anthropi, Moraxella sp., Aspergillus flavus, Penicillium expansum. Legionella sp. were not detected in all water samples.

Opportunistic pathogens relative to physicochemical factors in water storage tanks

“…Most of tbe isolates are among the opportunistic pathogens that may pose health risks to immunocompromised individuals. For example, Göksay et al (2008) andVenkatesh et al (2006) found such bacteria to be an important source of crossinfection in hospitals. Some produce toxins which may cause mild inflammation to serious toxic shock (Venkatesh et al 2006).…”

Evaluation of microbial contamination and distribution of sulphate-reducing bacteria in dental units

“…In this study, the highest levels of heterotrophic bacteria counts were found to be 200,200, 366,800 and 97,000 CFU ml −1 in air-water syringes, high-speed drills and the water source, respectively. Many studies have established the microbial contamination of dental units with reports of 10 3 -10 5 CFU ml −1 of bacteria detected in water samples from DUWLs (Göksay et al 2008;Miller 1996;Walker et al 2000;Williams et al 1995;Souza-Gugelmin et al 2003).…”

“…DUWLs support the formation of microbial biofilms since they are directly connected to municipal water, and also have stagnant water and average temperatures. It was reported as early as 1963 that DUWLs can be heavily contaminated with microorganisms (Blake 1963), and this has been confirmed more recently (Göksay et al 2008;Türetgen et al 2009). …”

Minimising microbial contamination in dental unit water systems and microbial control in dental hospitals

“…A range of fungi, yeasts, protozoa and amoebae has also been identifi ed in DUWLs, although these organisms are far less prevalent and signifi cantly less abundant than bacteria (Kelstrup et al ., 1977 ;Porteous et al ., 2003 ;Singh and Coogan, 2005 ;Szyma ń ska, 2005 ;Göksay et al ., 2008 ). Protozoa and amoebae present in natural waters are frequently parasitised by intracellular Legionella bacteria, which are released upon death of the protozoa/amoebae they infect .…”