16S and 23S rRNA Gene Mutation Independent Multidrug Resistance of Non-Tuberculous Mycobacteria Isolated from South Korean Soil.

Hyun-Eui Park,Woo Bin Park,Han Sang Yoo,Suji Kim,Soojin Shim,Young Bin Im,Hong-Tae Park

doi:10.3390/microorganisms8081114

Hyun-Eui Park, Woo Bin Park + Show 5 more

Open Access

https://doi.org/10.3390/microorganisms8081114

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Abstract

Non-tuberculous mycobacteria (NTM) are ubiquitous microorganisms that have the potential to cause disease in both humans and animals. Recently, NTM infections have rapidly increased in South Korea, especially in urbanized areas. However, the distribution of species and the antibiotic resistance profile of NTM in environmental sources have not yet been investigated. Therefore, we analyzed the distribution of species and the antibiotic resistance profile of NTM in soil within urban areas of South Korea. A total of 132 isolates of NTM were isolated from soil samples from 1 municipal animal shelter and 4 urban area parks. Among the 132 isolates, 105 isolates were identified as slowly growing mycobacteria (SGM) and 27 isolates as rapidly growing mycobacteria (RGM) based on the sequences of the rpoB and hsp65 genes. The antibiotic resistance patterns of NTM isolates differed from species to species. Additionally, a mutation in the rrs gene found in this study was not associated with aminoglycoside resistance. In conclusion, our results showed that NTM isolates from South Korean soil exhibit multidrug resistance to streptomycin, amikacin, azithromycin, ethambutol, isoniazid, and imipenem. These results suggest that NTM may pose a public threat.

Highlights

Non-tuberculous mycobacteria (NTM) are ubiquitous bacteria that are widely distributed in natural environments such as water, soil, and dust [1,2]
A total of 132 isolates of NTM were isolated from 50 soil samples from 5 sites, 105 of which were slowly growing mycobacteria (SGM), and the remaining 27 isolates were rapidly growing mycobacteria (RGM)
Limited in the number of sampling sites, our results suggest the extremely broad spectrum of antibiotic resistance in NTM isolates from the soils of urban areas in South Korea

Summary

Introduction

Non-tuberculous mycobacteria (NTM) are ubiquitous bacteria that are widely distributed in natural environments such as water, soil, and dust [1,2]. NTM infection mostly occurs by exposure to environmental sources of NTM such as soil, water, and dust [3,4,5]. After the ingestion of NTM through the respiratory system, NTM are cleared from the host by the immune system, and infection is not established. Predisposing factors such as repetitive exposure to NTM, an immunosuppressed condition, and the genetic susceptibility of the host lead to chronic infection [6,7,8]

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