Teng Ching-Hao, Wu Pin-Chieh, Tang Sen-Lin, Chen Yi-Chen, Cheng Ming-Fang, Huang Ping-Chih, Ko Wen-Chien, Wang Jiun-Ling
Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan.
Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan.
Microorganisms. 2021 Mar 31;9(4):722. doi: 10.3390/microorganisms9040722.
Colistin is one of the last-line antimicrobial agents against life-threatening infections. The distribution of the colistin resistance gene has been reported worldwide. However, most studies have focused on the distribution of -positive bacteria in humans, animals, food, and sewage; few have focused on their distribution in natural environments.
We conducted a large spatial survey of -positive at 119 sites in 48 rivers, covering the entire island of Taiwan. We investigated the relationship between the livestock or poultry density in the surveyed riverine area and the number of -positive in the river water. We then sequenced and characterized the isolated -positive plasmids.
Seven positive were isolated from 5.9% of the sampling sites. The -positive sites correlated with high chicken and pig stocking densities but not human population density or other river parameters. Four of the -positive strains harbored epidemic IncX4 plasmids, and three of them exhibited identical sequences with a size of 33,309 bp. One of the plasmids contained identical 33,309 bp sequences but carried an additional 5711-bp transposon (Tn3 family). To our knowledge, this is the first demonstration that -carrying IncX4 plasmids can contain an insertion of such transposons. All -positive isolates belonged to phylogenetic group A and harbored few known virulence genes.
This study showed a positive relationship between the number of -positive sites and high livestock and poultry density. The sequencing analyses indicated that the epidemic plasmid in the isolates circulates not only in humans, animals, and food but also in the associated environments or natural habitats in Taiwan, suggesting that the surveillance of antibiotics-resistance genes for livestock or poultry farm quality control should include their associated environments.
黏菌素是治疗危及生命感染的最后一线抗菌药物之一。黏菌素耐药基因的分布已在全球范围内报道。然而，大多数研究集中在人类、动物、食物和污水中阳性细菌的分布；很少有研究关注它们在自然环境中的分布。
我们对台湾全岛48条河流的119个地点进行了大规模的阳性空间调查。我们调查了被调查河流区域的畜禽密度与河水中阳性数量之间的关系。然后对分离出的阳性质粒进行测序和表征。
从5.9%的采样点分离出7株阳性。阳性位点与高鸡和猪存栏密度相关，但与人口密度或其他河流参数无关。4株阳性菌株携带流行的IncX4质粒，其中3株表现出相同的33309 bp序列。其中一个质粒包含相同的33309 bp序列，但携带一个额外的5711 bp转座子（Tn3家族）。据我们所知，这是首次证明携带的IncX4质粒可以包含这种转座子的插入。所有阳性分离株都属于系统发育A组，并且携带很少已知的毒力基因。
本研究表明阳性位点数量与高畜禽密度之间存在正相关。测序分析表明，分离株中的流行质粒不仅在人类、动物和食物中传播，而且在台湾的相关环境或自然栖息地中传播，这表明对畜禽养殖场质量控制的抗生素耐药基因监测应包括其相关环境。
