Isolation of Enterobacteriaceae and non-fermenting Gram-negative bacilli (NFGNB) from Dental Unit Water Lines (DUWL) in a tertiary care institutional setup
Background: The quality of dental unit water lines (DUWL) is of considerable importance since patients and dental staff are regularly exposed to water and aerosols generated from dental units which thereby influence the individual patient outcome and health-care associated morbidity. The aim of the present study was to determine the microbiological quality of water used, presence of biofilms and also the potential of isolated bacterial species in producing biofilms within DUWL.
Methods: Thirty DUWL samples were collected from various departments of Manipal College of Dental Sciences, Mangalore. Bacteriological analysis was done for the presence of various bacterial contaminants. Presence of biofilms on DUWLs and potential of bacterial isolates to form biofilm were also determined.
Results: Seven of 30 samples (23.3%), were found to be of unsatisfactory quality (coliform count > 200 CFU/ml), most frequently from air/water syringes. A total of 45 strains were isolated from 14 water samples. Genera isolated were Escherichia spp., Enterobacter spp., Klebsiella spp., Pseudomonas spp. and Acinetobacter spp. Four of 10 samples from DUWL tubing showed presence of biofilms (40%), formed mostly by Acinetobacter spp. and Pseudomonas spp. Out of 45 strains that were isolated, 19 strains displayed ability to form biofilms. Maximum number (10) isolates formed biofilms with 48 hours.
Conclusion: Exposure to contaminated water from DUWL poses threat to the well-being of the patient and the health care personnel as well. Hence, measures should be initiated to ensure the optimum quality of DUWL water.
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