圖中為研究者在Pearlsian海灣,，背景為洞穴中方解石的相關信息 (Credit: Copyright Max Wisshak)
近日，國際雜志PLoS One在線刊登了國外研究人員的最新研究成果,，在文章中，來自麥克馬斯特大學和阿克倫大學的研究者在新墨西哥的龍舌蘭洞穴發(fā)現(xiàn)了一種普遍流行的抗生素抗性細菌,，龍舌蘭洞穴是世界上最深最大的洞穴,，人類已經(jīng)有超過四百萬年沒有與該洞穴接觸了。
研究者Wright表示,，抗生素抗藥性和細菌之間的關系已經(jīng)有億萬年了,，但是我們緊緊是在過去的70年里才開始理解它們之間的這種關系。環(huán)境中有很多抗生素可以被找到來應對目前無法治愈的感染性疾病,。研究者從洞穴壁上收集了許多細菌菌株,，然后檢測了這些細菌的耐藥性，研究者發(fā)現(xiàn)沒有一種細菌可以致病,，而且這些細菌也沒有一種暴露于人類所用的抗生素之中,。所有菌株至少對一種抗生素有抗性，而且有些細菌對14種不同的抗生素也有抗性,。
研究者也識別出了一種和能引起炭疽的細菌相關的抗性細菌,，這種抗性原先在診所中出現(xiàn)過。Barton教授表示,，這樣,，我們就可以告訴醫(yī)生，將來需要知道細菌存在的抗性,，這樣當這種細菌出現(xiàn)在診所的時候,，醫(yī)生就可以知道如何應對了,。細菌對抗生素耐藥性的上升對于人類健康來說非常重要，當細菌出現(xiàn),，比如多重耐藥性的金黃色葡萄球菌的出現(xiàn),，以至于任何藥物都不能治療的時候，那么這種細菌是如何獲得耐藥性的,，這就成為我們必須思考的一個問題,。
在個別情況下，這些微生物可以對7種甚至更多藥物產(chǎn)生耐藥性,，而且用傳統(tǒng)的藥物根本無法治療,，這樣一來，醫(yī)生只能通過手術的方法切掉被感染的組織從而來抑制疾病的蔓延,。實際上,，在環(huán)境中發(fā)現(xiàn)的產(chǎn)生耐藥性的菌株對人類是無害的?？股卦臼窃谵r(nóng)業(yè)中使用的,，一般我們很難發(fā)現(xiàn)一種環(huán)境，在這種環(huán)境中抗生素不能施加某種效應,，但是在龍舌蘭洞穴中,，我們發(fā)現(xiàn)了自然界中抗生素抗性存在的庫。龍舌蘭洞穴自從1986年被發(fā)現(xiàn),，每年都限制研究者進入,，這個洞穴被一層不透水的巖石層所環(huán)繞，意味著它可以儲存至少10000年的水以使各種耐抗生素的細菌生存,。（生物谷：T.Shen編譯）
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doi:10.1371/journal.pone.0034953
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Antibiotic Resistance Is Prevalent in an Isolated Cave Microbiome
Kirandeep Bhullar1, Nicholas Waglechner1, Andrew Pawlowski1, Kalinka Koteva1, Eric D. Banks2, Michael D. Johnston2, Hazel A. Barton2, Gerard D. Wright1*
Antibiotic resistance is a global challenge that impacts all pharmaceutically used antibiotics. The origin of the genes associated with this resistance is of significant importance to our understanding of the evolution and dissemination of antibiotic resistance in pathogens. A growing body of evidence implicates environmental organisms as reservoirs of these resistance genes; however, the role of anthropogenic use of antibiotics in the emergence of these genes is controversial. We report a screen of a sample of the culturable microbiome of Lechuguilla Cave, New Mexico, in a region of the cave that has been isolated for over 4 million years. We report that, like surface microbes, these bacteria were highly resistant to antibiotics; some strains were resistant to 14 different commercially available antibiotics. Resistance was detected to a wide range of structurally different antibiotics including daptomycin, an antibiotic of last resort in the treatment of drug resistant Gram-positive pathogens. Enzyme-mediated mechanisms of resistance were also discovered for natural and semi-synthetic macrolide antibiotics via glycosylation and through a kinase-mediated phosphorylation mechanism. Sequencing of the genome of one of the resistant bacteria identified a macrolide kinase encoding gene and characterization of its product revealed it to be related to a known family of kinases circulating in modern drug resistant pathogens. The implications of this study are significant to our understanding of the prevalence of resistance, even in microbiomes isolated from human use of antibiotics. This supports a growing understanding that antibiotic resistance is natural, ancient, and hard wired in the microbial pangenome.
