Tetracycline Resistance Genes Identified from Distinct Soil Environments in China by Functional Metagenomics

Abstract

Soil microbiota represents one of the ancient evolutionary origins of antibiotic resistance and has been increasingly recognized as a potentially vast unstudied reservoir of resistance genes with possibilities to exchange with pathogens. Tetracycline resistance is one of the most abundant antibiotic resistances that may transfer among clinical and commensal microorganisms. To investigate tetracycline resistance genes from soil bacteria in different habitats, we performed functional analysis of three metagenomic libraries derived from soil samples collected from Yunnan, Sichuan, and Tibet, respectively, in China. We found efflux transporter genes form all the libraries, including 21 major facilitator superfamily efflux pump genes and one multidrug and toxic compound extrusion (MATE) transporter gene. Interestingly, we also identified two tetracycline destructase genes, belonging to a newly described family of tetracycline-inactivating enzymes that scarcely observed in clinical pathogens, from the Tibet library. The inactivation activity of the putative enzyme was confirmed in vitro by biochemical analysis. Our results indicated that efflux pumps distributed predominantly across habitats. Meanwhile, the mechanism of enzymatic inactivation for tetracycline resistance should not be neglected and merits further investigation.

Transcriptional and Functional Analysis of Bifidobacterium animalis subsp. lactis Exposure to Tetracycline

“…However, there were over 800 genes in the B. animalis subsp. lactis genomes, nearly 300 of which were upregulated in the LOG experiments, that were not assigned to a metabolic category, and novel antibiotic resistance genes in bifidobacteria are constantly being identified ( 69 ). Thus, there are many factors yet to be discovered that may also contribute broadly to antibiotic resistance in food and probiotic microorganisms.…”

Tetracycline-Inactivating Enzymes

“…The tetX gene has also been observed in a variety of environmental bacteria, including Myroides odoratimimus ( Ming et al, 2017 ), Sphingobacterium sp. ( Ghosh et al, 2009 , 2014 ), and Flavobacterium psychrophilum ( Duchaud et al, 2018 ), and metagenomic samples including Chinese soil ( Wang et al, 2017 ), human feces ( Ohashi and Fujisawa, 2017 ), and hospital wastewater ( Wang et al, 2018 ). The tetX gene is encountered in a wide range of ecosystems (human gut, soil, hospital wastewater) and is present on mobile genetic elements primed for horizontal gene transfer.…”

Prevalence and proliferation of antibiotic resistance genes in the subtropical mangrove wetland ecosystem of South China Sea

“…This coincided with a point of view that lots of ARGs evolved from natively functional genes of the bacterium (Wright, ). Fluoroquinolone is the most used antibiotic in China and the fluoroquinolone resistant genes were prevalent in China (Xu et al, ; Zhang et al, ; Zhang, Lu, Wang, Pang, & Zhao, ), similar situation was found in several relatively abundant resistance types such as β‐lactam and tetracycline (Wang et al, ; ZHANG et al, , ; Zhu et al, ).…”