Klebsiella to Salmonella gene transfer within rumen protozoa:: Implications for antibiotic resistance and rumen defaunation
Klebsiella to Salmonella gene transfer within rumen protozoa:: Implications for antibiotic resistance and rumen defaunation
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DOI：
10.1016/j.vetmic.2005.12.004
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发表时间：
2006-05-31
影响因子：
3.3
通讯作者：
Franklin, S. K.
中科院分区：
文献类型：
--
作者：
McCuddin, Z. P.;Carlson, S. A.;Franklin, S. K.
长期以来，瘤胃被认为是微生物基因转移的场所。瘤胃原生动物（RPz）是细菌的活跃捕食者，可以携带抗生素抗性基因。在这项研究中，RPZ被评估为两种细菌物种，沙门氏菌和克雷伯氏菌之间的基因转移位点。一个克雷伯菌分离株携带携带bla（CMY-2）的质粒，编码一种赋予头孢曲松耐药性的超广谱β-内酰胺酶，而沙门氏菌对头孢曲松敏感，但能够在原生动物中繁殖。体外研究表明，在沙门氏菌和克雷伯氏菌与从成年牛和山羊获得的RPz共孵育后，可以分离出头孢曲松耐药沙门氏菌。头孢曲松耐药沙门氏菌没有恢复在原生动物吞噬抑制剂的存在下，或当一个原生动物敏感沙门氏菌是共孵育的一部分。这种转移事件还观察到在体外的原生动物独立的压力，虽然在一个显着较低的频率。基因转移事件与细菌接合有关，因为接合抑制剂萘啶酸扰乱了这种现象。从用头孢曲松耐药克雷伯菌和头孢曲松敏感沙门氏菌共同攻毒的小牛、绵羊和山羊中回收头孢曲松耐药沙门氏菌。然而，在联合攻毒前除菌的小牛和绵羊中未观察到转移事件。此外，沙门氏菌transconjugants分离从单独的牛体内研究，涉及携带质粒赋予大肠杆菌素活性的克雷伯氏菌供体，而没有这样的transconjugants从defaunated小牛获得。这些结果为评价和预防反刍动物中存在的病原体的抗生素抗性和其他选择性优势的传播提供了重要依据。由爱思唯尔公司出版
The rumen has long been thought to be a site of gene transfer for microorganisms. Rumen protozoa (RPz) are active predators of bacteria that can harbor antibiotic resistance genes. In this study, RPZ were assessed as sites of gene transfer between two bacterial species, Salmonella and Klebsiella. One Klebsiella isolate carried a plasmid bearing bla(CMY-2), encoding an extended-spectrum beta-lactamase conferring ceftriaxone resistance, while the Salmonella was susceptible to ceftriaxone yet capable of thriving within protozoa. In vitro studies revealed that ceftriaxone-resistant Salmonella could be isolated following coincubation of Salmonella and Klebsiella with RPz obtained from adult cattle and goats. Ceftriaxone-resistant Salmonella were not recovered in the presence of an inhibitor of protozoa engulfment or when a protozoa-sensitive Salmonella was part of the coincubation. This transfer event was additionally observed in vitro for protozoa-independent stressors although at a significantly lower frequency. The gene transfer event was related to bacterial conjugation since a conjugation inhibitor, nalidixic acid, perturbed the phenomenon. Ceftriaxone-resistant Salmonella were recovered from calves, sheep, and goats co-challenged with ceftriaxone-resistant Klebsiella and ceftriaxone-sensitive Salmonella. However, the transfer event was not observed in calves and sheep that were defaunated prior to the co-challenge. Moreover, Salmonella transconjugants were isolated from separate bovine in vivo studies involving a Klebsiella donor carrying a plasmid conferring colicin activity while no such transconjugants were obtained from defaunated calves. These results provide an important basis for evaluating and preventing the spread of antibiotic resistance and other selective advantages for pathogens present in ruminants. Published by Elsevier B.V.