Dental Unit Waterlines in Quito and Caracas Contaminated with Nontuberculous Mycobacteria: A Potential Health Risk in Dental Practice

Orlando J. Castellano Realpe, Johanna C. Gutiérrez, Deisy A. Sierra, Lourdes A. Pazmiño Martínez, Yrneh Y. Prado Palacios, Gustavo Echeverría and Jacobus H. de Waard
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Orlando J. Castellano Realpe: Facultad de Ciencias Químicas, Universidad Central del Ecuador, 170521 Quito, Ecuador
Johanna C. Gutiérrez: Facultad de Medicina. Escuela de Bioanálisis, Universidad Central de Venezuela, 1053 Caracas, Venezuela
Deisy A. Sierra: Facultad de Medicina. Escuela de Bioanálisis, Universidad Central de Venezuela, 1053 Caracas, Venezuela
Lourdes A. Pazmiño Martínez: Facultad de Ciencias Químicas, Universidad Central del Ecuador, 170521 Quito, Ecuador
Yrneh Y. Prado Palacios: Instituto de Biomedicina “Dr. Jacinto Convit”, Universidad Central de Venezuela, 1010 Caracas, Venezuela
Gustavo Echeverría: Instituto de Investigación en Salud Pública y Zoonosis CIZ, Universidad Central del Ecuador, 170521 Quito, Ecuador
Jacobus H. de Waard: Instituto de Biomedicina “Dr. Jacinto Convit”, Universidad Central de Venezuela, 1010 Caracas, Venezuela

IJERPH, 2020, vol. 17, issue 7, 1-11

Abstract: Three cases of severe odontogenic infections due to nontuberculous mycobacteria (NTM) in Venezuela that were directly associated with dental procedures and the finding of dental unit waterlines (DUWLs) in dental offices that were colonized with mycobacteria species was the reason for assessing the water quality of DUWLs in dental offices in two capital cities in South America, namely, Quito and Caracas. The main water supplies and the water from 143 DUWLs in both cities were sampled and especially checked for contamination with NTM. To measure the overall bacteriological quality of the water also the presence of heterotrophic bacteria, coliform bacteria, and Pseudomonas was determined. Results showed that respectively 3% and 56% of the DUWLs in Quito and Caracas yielded NTM species (up to 1000 colony-forming units (CFU)/mL). Furthermore, high and unacceptable total viable counts of heterotrophic bacteria and/or coliform bacteria and Pseudomonas were detected in 73% of the samples. We conclude that, in both cities, the water in the majority of DUWLs was contaminated with NTM and other potential pathogens, presenting a risk to human health. The detection of NTM in DUWL water with acceptable heterotrophic bacteria counts shows the need to include NTM in water quality testing. Mycobacteria are more resistant to disinfection procedures than other types of vegetative bacteria, and most testing protocols for DUWLs do not assess mycobacteria and thus do not guarantee risk-free water.

Keywords: dental unit waterline (DUWL); biofilm; dental infection control; heterotrophic plate count (HPC); coliform bacteria; Pseudomonas aeruginosa; nontuberculous mycobacteria (NTM) (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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