Microbial Contamination of Waterline in Dental Units: Bacterial Contamination of Waterline in Dental Clinics by Pseudomonas aeruginosa and Legionella pneuomophila

This is the first study in Jordan to determine the degree of bacterial contamination of water outlets from high-speed drill and air/water syringe waterlines in dental clinics. Total heterotrophic bacterial counts (HPC), in addition to Pseudomonas aeruginosa, and Legionella pneuomophila as opportunistic pathogens were investigated in the source water, high-speed drill and air/water syringe waterlines. Heterotrophic bacterial counts (HPCs) exceeded 500 CFU/ml in 26% of the water sources supplying the units. Pseudomonas aeruginosa was detected in 12% of the source water sample supplying the dental unit in a range of 1-500 CFU/ml. Concentration ranging between 1-100 CFU/ml of Legionella pneuomophila of serogroup 1 was detected in 20% of source water samples. This study has shown that dental unit waterlines were not complying with International Drinking Water standards for heterotrophic mesophilic bacterial count (>500 CFU/ml), nor with the American Dental Association guidelines (>200 CFU/ml). The presence of Pseudomonas aeruginosa and Legionella pneuomophila is an indication of low water quality in dental unit waterlines.