Microbiological Quality and Presence of Clinically Relevant Nontuberculous Mycobacteria in Purified Water from Vending Machines in Michoacan, Mexico.

Ricardo Jiovanni Soria-Herrera, Janet Karina Hernández-Ramón, Marco Esteban Álvarez-Pérez, Miriam Alejandra Pérez-Sandoval, Margarita Hernandez-Mixteco, Olga Lidia Valenzuela, Eliud Alfredo Garcia-Montalvo, Paola Castillo-Juárez, Sandra Rivera-Gutiérrez, Gilberto Cornejo-Estudillo, Moises León-Juárez, Addy Cecilia Helguera-Repetto, Victoria Campos-Peña, Ma Guadalupe Zanella-Vargas, Graciela Castro-Escarpulli, Carlos Cortes-Penagos, Jorge Francisco Cerna-Cortés

Journal: Pathogens (Basel, Switzerland) 2025;14(9):

PMID: 41011785

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Abstract

In this study, 104 purified water samples were collected from vending machines in the three main cities of Michoacan, Mexico, to assess microbiological quality and the occurrence of diarrheagenic pathotypes (DEP) and nontuberculous mycobacteria (NTM). Aerobic mesophilic bacteria were detected in all samples, with concentrations ranging from 0.95 to 3.71 log CFU/mL. A total of 62, 34, and 25 samples tested positive for total coliforms, fecal coliforms, and , respectively. Sixty-two samples exceeded Mexico's official guideline. None of the 58 strains isolated from the 25 -positive samples belonged to DEP. NTM species were recovered from 47 samples, including (n = 18), (n = 11), (n = 7), (n = 3), (n = 2), (n = 1), (n = 1), and (n = 1). Three additional isolates could not be identified. All NTM strains produced biofilm and exhibited sliding motility. These findings highlight significant microbiological risks associated with vending machine water and underscore the need for manufacturers to ensure regular maintenance to provide safe and reliable purified water to consumers.

Address: Facultad de Químico Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58240, Mexico.; Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico.; Facultad de Químico Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58240, Mexico.; Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico.; Facultad de Ciencias Químicas, Universidad Veracruzana, Orizaba 94340, Mexico.; Facultad de Ciencias Químicas, Universidad Veracruzana, Orizaba 94340, Mexico.; Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11340, Mexico.; Escuela José Ma. Pastrana, Secretaría de Educación Pública, Yecapixtla 62829, Mexico.; Departamento de Inmunobioquimica, Instituto Nacional de Perinatología Isidro Espinosa de los Reyes, Ciudad de México 11000, Mexico.; Laboratorio Experimental de Enfermedades Neurodegenerativas, Instituto Nacional de Neurología y Neurocirugía, Manuel Velasco Suárez, Ciudad de México 14269, Mexico.; Jurisdicción Sanitaria VI, Secretaria de Salud, Irapuato 36547, Mexico.

DOI: 10.3390/pathogens14090886

MeSH Terms: Mexico, Nontuberculous Mycobacteria, Water Microbiology, Escherichia coli, Humans, Drinking Water