Presence in Dental Unit Waterlines: A Cultural and Molecular Investigation in the West Bank, Palestine.

A bacterium is ubiquitous in water distribution systems, including dental unit waterlines (DUWLs). Legionellosis is atypical pneumonia, including Legionnaires' disease (LD) and the less acute form of Pontiac fever. Legionellosis occurs as a result of inhalation/aspiration of aerosolized -contaminated water by susceptible patients, health workers, and dentists. In this study, we undertook to determine the prevalence of in water and biofilm samples from Tap and DUWLs collected from five sites of dental clinics and faculties across the West Bank. Water samples were tested for physical and chemical parameters. The study samples included 185 samples, 89 (48%) water samples, and 96 (52%) biofilm swabs, which were analyzed by cultivation-dependent analysis (CDA) and by the cultivation-independent technique (CIA). Also, partial sequencing of the 16S rRNA gene for fifteen isolates was performed for quality assurance and identification. was isolated from 28 (15%) of 185 samples using CDA and was detected in 142 (77%) of 185 samples using CIA. The abundance of culturable was low in DUWL of the sampling sites (range: 27-115 CFU/Liter). PCR was 5× more sensitive than the culture technique. Sg 1 was detected in (75%) of the isolates, while (25%) isolates were Sg 2-14. All fifteen sequenced isolates were identified as ≥ 94.5%. The analysis of phylogenetic tree showed that branch clearly identified and distinguished from other branches. These results show that DUWLs of the examined dental clinics and faculties are contaminated with . This finding reveals a serious potential health risk for infection of immunocompromised patients and dentists' post-exposure.