Investigation of Microbial Contamination in Surfaces and Waterlines of Dental Units in Terms of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Coliforms

Water supply systems and various parts of dentistry unit have the ability to aggregate biofilms and thus the transmission of dangerous diseases to staff and patients. The aim of this study was to determine the bacterial contamination of surfaces and water lines of dental units of health center (Qods 2) in Divandareh city.

This cross-sectional descriptive study was conducted on dental units of the health center (Qods 2) in Divandareh city in 2019. 125 samples were collected from different parts of the units including unit lamp handle, lamp ON/OFF power button, open/close bolt of unit water, setting switch button (before and after disinfecting), and the inlet and outlet water of units. The samples were tested for Staphylococcus aureus, Pseudomonas aeruginosa, Coliforms and Escherichia coli.

The results of this study showed that all samples collected from the studied parts of the units including unit lamp handle, lamp ON/OFF power button, open/close bolt of unit water, and setting switch button were positive as presence of Staphylococcus aureus, Pseudomonas aeruginosa, and coliforms before and after disinfection. Also, the unit lamp handle and setting switch button were positive as Escherichia coli. The inlet and outlet water were also positive for all the studied bacteria. The number of Staphylococcus aureus bacteria in the handle of the unit lamp before disinfection (210±80.5 CFU/ml) and in the ON/OFF button of the lamp after disinfection (300±82.6 CFU/ml) were higher than the permissible amount (200 CFU/ml). Also, the number of Pseudomonas aeruginosa bacteria detected in setting switch button, before disinfection, was higher (200±75.2) than the allowable value.

According to the obtained results, the contamination level of water and surface of the studied dental units was high. Also, identifying of the considerable number of bacteria at the different surfaces of the units, indicating the improper use of the disinfectants and the possibility of biofilms presence in the unit waterlines.