Dipartimento di Biologia, University Tor Vergata, Roma, Italy.
PLoS One. 2010 Feb 1;5(2):e8989. doi: 10.1371/journal.pone.0008989.
Antibiotic resistance, evolving and spreading among bacterial pathogens, poses a serious threat to human health. Antibiotic use for clinical, veterinary and agricultural practices provides the major selective pressure for emergence and persistence of acquired resistance determinants. However, resistance has also been found in the absence of antibiotic exposure, such as in bacteria from wildlife, raising a question about the mechanisms of emergence and persistence of resistant strains under similar conditions, and the implications for resistance control strategies. Since previous studies yielded some contrasting results, possibly due to differences in the ecological landscapes of the studied wildlife, we further investigated this issue in wildlife from a remote setting of the Galapagos archipelago.
METHODOLOGY/PRINCIPAL FINDINGS: Screening for acquired antibiotic resistance was carried out in commensal enterobacteria from Conolophus pallidus, the terrestrial iguana of Isla Santa Fe, where: i) the abiotic conditions ensure to microbes good survival possibilities in the environment; ii) the animal density and their habits favour microbial circulation between individuals; and iii) there is no history of antibiotic exposure and the impact of humans and introduced animal species is minimal except for restricted areas. Results revealed that acquired antibiotic resistance traits were exceedingly rare among bacteria, occurring only as non-dominant strains from an area of minor human impact.
CONCLUSIONS/SIGNIFICANCE: Where both the exposure to antibiotics and the anthropic pressure are minimal, acquired antibiotic resistance traits are not normally found in bacteria from wildlife, even if the ecological landscape is highly favourable to bacterial circulation among animals. Monitoring antibiotic resistance in wildlife from remote areas could also be a useful tool to evaluate the impact of anthropic pressure.
抗生素耐药性在细菌病原体中不断演变和传播，对人类健康构成严重威胁。抗生素在临床、兽医和农业实践中的使用为获得性耐药决定因素的出现和持续提供了主要的选择性压力。然而，即使在没有抗生素暴露的情况下，如野生动物中的细菌，也发现了耐药性，这就提出了一个问题，即在类似条件下，耐药菌株的出现和持续存在的机制是什么，以及这对耐药控制策略有何影响。由于之前的研究结果存在一些相互矛盾的地方，可能是由于研究野生动物的生态景观存在差异，我们在加拉帕戈斯群岛偏远地区的野生动物中进一步调查了这个问题。
方法/主要发现：在来自 Santa Fe 岛的陆生鬣蜥 Conolophus pallidus 的共生肠杆菌中进行了获得性抗生素耐药性筛选，其中：i）非生物条件确保了微生物在环境中有良好的生存可能性；ii）动物密度和它们的习惯有利于个体之间的微生物循环；iii）没有抗生素暴露的历史，人类和引入的动物物种的影响除了受限制的区域外，是最小的。结果表明，获得性抗生素耐药性特征在细菌中极为罕见，仅在人类影响较小的区域作为非优势菌株出现。
结论/意义：在抗生素暴露和人为压力都最小的情况下，即使生态景观非常有利于动物之间的细菌循环，野生动物中的细菌也通常不会出现获得性抗生素耐药性特征。监测偏远地区野生动物中的抗生素耐药性也可以成为评估人为压力影响的有用工具。
