Identification of Nontuberculous Mycobacteria in Drinking Water in Cali, Colombia

Andrés F Dávalos,Carolina Montoya-Pachongo,Beatriz E Ferro,Andrea Rengifo,Lorena Díaz-Ordoñez,Daniela Guerrero,Gustavo Díaz,Pamela K Garcia

doi:10.3390/ijerph18168451

Abstract

Nontuberculous mycobacteria (NTM) are ubiquitous microorganisms naturally resistant to antibiotics and disinfectants that can colonize drinking water supply systems. Information regarding the spread of NTM in specifically South America and Colombia is limited. We aimed to identify and characterize NTM present in tap water samples from Cali, Colombia. Drinking water samples and faucet biofilm swabs were collected in 18 places, including the city’s three main water treatment plants (WTPs). Filter-trapped material and eluates (0.45 μm) from swab washes were plated in 7H11 agar plates. Suspected colonies were evaluated microscopically, and NTM species were identified based on the rpoB gene. Antibiotic susceptibility testing was also performed. Fifty percent (9/18) of sampling points were positive for NTM (including two WTPs), from which 16 different isolates were identified: Mycobacterium mucogenicum (8/16), M. phocaicum (3/16), M. chelonae (2/16), M. mageritense (2/16), and M. fortuitum (1/16), all rapidly growing mycobacteria. A susceptibility profile was obtained from 68.75% (11/16) of the isolates. M. chelonae was the most resistant species. All NTM isolated are potentially responsible for human diseases; our findings might provide a baseline for exploring NTM transmission dynamics and clinical characterization, as well as potential associations between NTM species found in drinking water and isolates from patients.

Highlights

There are few reports describing the distribution of Nontuberculous mycobacteria (NTM) in South America, Zweijpfenning et al reported that the species most frequently found in this part of the world are those of the Mycobacterium avium complex (MAC) complex, with a frequency of 34%, followed by M. kansasii with 17%, M. gordonae with 15%, and M
Few studies have been reported on the presence of NTM in drinking water in Latin America
This work represents a contribution to improve the knowledge regarding the presence of NTM in drinking water in the city of Cali, Colombia

Summary

Introduction

Nontuberculous mycobacteria (NTM) are aerobic, nonmotile, and ubiquitous organisms found in water and soil. Their cell wall composition, biofilm formation ability, resistance to high temperature, and low pH allow these bacteria to be naturally resistant to antibiotics and disinfectants, as well as colonize different moist environments, including drinking water supply systems [1,2,3]. NTM species have been isolated from both patients and environmental sources; more than 200 species of NTM have been characterized by molecular biology techniques [4,5]. The most common NTM associated with human infection include Mycobacterium avium complex (MAC), M. kansasii, M. xenopi, and

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