Microbial environmental contamination in Italian dental clinics: A multicenter study yielding recommendations for standardized sampling methods and threshold values

• Published in: The Science of the total environment Vol. 420; pp. 289 - 299
• Main Authors: Pasquarella, Cesira, Veronesi, Licia, Napoli, Christian, Castiglia, Paolo, Liguori, Giorgio, Rizzetto, Rolando, Torre, Ida, Righi, Elena, Farruggia, Patrizia, Tesauro, Marina, Torregrossa, Maria V., Montagna, Maria T., Colucci, Maria E., Gallè, Francesca, Masia, Maria D., Strohmenger, Laura, Bergomi, Margherita, Tinteri, Carola, Panico, Manuela, Pennino, Francesca, Cannova, Lucia, Tanzi, Marialuisa
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-03-2012; Elsevier
• Subjects: Air; Air Microbiology; Applied sciences; Atmospheric pollution; Dental clinic; Dental Clinics; Dental Equipment - microbiology; Dental unit water system; dentistry; Environmental Monitoring - standards; Equipment Contamination; Exact sciences and technology; Humans; Indoor pollution and occupational exposure; Italy; Legionella; Microbial contamination; Pollution; Pseudomonas aeruginosa; surface water; Surfaces; tap water; Threshold Limit Values; Water; Water Microbiology; water pollution; work schedules; Italy; Europe; Water; Surfaces; Dental clinic; Air; Dental unit water system; Microbial contamination; Pseudomonadales; Work place; Microbiology; Legionella; Occupational exposure; Pseudomonas; Health and environment; Bioaerosol; Pathogenic; Bacteria; Pseudomonadaceae; Sampling; Biological contamination; Public health; Gram negative bacteria; Legionellaceae; Dentistry; Tap water; Clinic; Health center; Aerosols; Indoor pollution; Water pollution
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2012.01.030

A microbiological environmental investigation was carried out in ten dental clinics in Italy. Microbial contamination of water, air and surfaces was assessed in each clinic during the five working days, for one week per month, for a three-month period. Water and surfaces were sampled before and after clinical activity; air was sampled before, after, and during clinical activity. A wide variation was found in microbial environmental contamination, both within the participating clinics and for the different sampling times. Before clinical activity, microbial water contamination in tap water reached 51,200cfu/mL (colony forming units per milliliter), and that in Dental Unit Water Systems (DUWSs) reached 872,000cfu/mL. After clinical activity, there was a significant decrease in the Total Viable Count (TVC) in tap water and in DUWSs. Pseudomonas aeruginosa was found in 2.38% (7/294) of tap water samples and in 20.06% (59/294) of DUWS samples; Legionella spp. was found in 29.96% (89/297) of tap water samples and 15.82% (47/297) of DUWS samples, with no significant difference between pre- and post-clinical activity. Microbial air contamination was highest during dental treatments, and decreased significantly at the end of the working activity (p<0.05). The microbial buildup on surfaces increased significantly during the working hours. This study provides data for the establishment of standardized sampling methods, and threshold values for contamination monitoring in dentistry. Some very critical situations have been observed which require urgent intervention. Furthermore, the study emphasizes the need for research aimed at defining effective managing strategies for dental clinics.
► We monitored the microbial environmental contamination in ten dental clinics. ► A high variability was found both between the clinics and the different sampling times. ► Air and surface contamination increased significantly during clinical activity. ► Water contamination values appeared particularly worrying. ► Appropriate preventive measures should be developed.