Contents lists available at ScienceDirect International Journal of Food Microbiology journal homepage: www.elsevier.com/locate/ijfoodmicro Short communication Bacteriological quality of bottled water obtained from Mexico City small water purification plants: Incidence and identification of potentially pathogenic nontuberculous mycobacteria species Jorge Francisco Cerna-Cortes a,1 , Ana Laura Cortes-Cueto a,1 , Daniel Villegas-Martínez a , Nancy Leon-Montes a , Laura P. Salas-Rangel a , Sandra Rivera-Gutierrez a , Daniel Lopez-Hernandez b , Addy Cecilia Helguera-Repetto c , Elizabeth Fernandez-Rendon a , Jorge Alberto Gonzalez-y-Merchand a, ⁎ a Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas, Instituto Politecnico Nacional, Prolongacion Carpio y Plan de Ayala S/N, Col. Casco de Santo Tomas, Ciudad de Mexico 11340, Mexico b Centro de Investigacion y de Educacion Continua, S.C. Oyameles # 30, Col. La Perla, Ciudad Nezahualcoyotl, Estado de Mexico 57820, Mexico c Departamento de Inmunobioquimica, Instituto Nacional de Perinatologia Isidro Espinosa de los Reyes, Montes Urales # 800, Col. Lomas Virreyes, Ciudad de Mexico 11000, Mexico ARTICLE INFO Keywords: Purified water Microbiological quality Mycobacteria ABSTRACT The aim of this study was to determine the bacteriological quality of bottled water samples obtained from small purification plants located in Mexico City and to identify potentially pathogenic nontuberculous mycobacteria (NTM) species found in these samples. All 111 samples analyzed were positive for aerobic mesophilic bacteria (AMB) and 46 (41.4%) did not comply with Mexico's Official Guidelines. Sixty-nine (62.1%) and 23 (20.7%) water samples were positive for total coliforms (TC) and fecal coliforms (FC), respectively. A total of 81 (72.9%) of the water samples exceeded the maximum allowed limit stipulated in the guideline. Thirty-three (29.7%) of the purified water samples were positive for NTM, being recovered a total of 40 isolates. These NTM isolates were identified using three molecular markers (hsp65, rrs and rpoB genes) which corresponded to the fast- growing mycobacteria M. chelonae (n = 12), M. porcinum (n = 8), M. senegalense (n = 5), M. abscessus (n = 4), M. septicum (n = 4), M. wolinskyi (n = 3), M. mucogenicum (n = 2), M. fortuitum (n = 1) and M. sp. (n = 1). In seven purified water samples, two different NTM species were isolated simultaneously. Overall, these results showed that most of the purified bottled water samples analyzed in this study had unsatisfactory microbiological quality and some harbored NTM associated with illness. Our data could hasten health authorities to intensify efforts in the routine monitoring of activities in the purified bottled water industry in order to supply safe and healthy water to the public. 1. Introduction Since the September 1985 earthquake, the population of Mexico has increasingly consumed bottled water because at that moment, it was not safe to consume water directly from the distribution system (PAHO, 1985). Moreover, the seventh cholera pandemic that occurred during the 1990s also exerted an influence on the high consumption of bottled water in Mexico. This pandemic resulted in 45,977 cases of cholera between 1991 and 2002, with a fatality rate of 1.2% (Sepulveda et al., 2006). In Mexico, consumption of purified bottled water continues to in- crease steadily because of public concerns about the possibility of finding microbial and chemical contaminants in tap water. The per- centage of households that buy bottled water increased by five per- centage points in recent years, moving up from 70.8% in 2015 to 76.3% in 2017 (INEGI Mexico, 2018). Because of this demand, the water bottling industry has been booming throughout the country. In Mexico City alone, the fifth most populated city of the world (World Population Review, 2019a), the number of small water purification plants that sell purified bottled water in 20 L jugs increased by 85%, from 1232 in 2012 https://doi.org/10.1016/j.ijfoodmicro.2019.108260 Received 26 March 2019; Received in revised form 1 July 2019; Accepted 3 July 2019 ⁎ Corresponding author. E-mail address: jgonzal1212@yahoo.com.mx (J.A. Gonzalez-y-Merchand). 1 Contributed equally. International Journal of Food Microbiology 306 (2019) 108260 Available online 05 July 2019 0168-1605/ © 2019 Elsevier B.V. All rights reserved. T