Critical role of multidrug efflux pump CmeABC in bile resistance and in vivo colonization of Campylobacter jejuni
Critical role of multidrug efflux pump CmeABC in bile resistance and in vivo colonization of Campylobacter jejuni
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DOI：
10.1128/iai.71.8.4250-4259.2003
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发表时间：
2003-08-01
影响因子：
3.1
通讯作者：
Zhang, OJ
中科院分区：
文献类型：
--
作者：
Lin, J;Sahin, O;Zhang, OJ
CmeABC作为一种多药外排泵，促进了弯曲杆菌对多种抗菌剂的耐药性。在这项研究中，我们研究了CmeABC在胆汁抵抗中的作用及其在空肠弯曲菌在鸡肠道适应中的作用，鸡是弯曲杆菌的自然宿主和主要储存库。CmeABC的失活显著降低了弯曲杆菌对各种胆盐的抵抗力。在培养基中加入2 mM胆汁酸对cmeABC突变体的体外生长有抑制作用，但对野生型菌株的生长没有影响。鸡肠十二指肠、空肠和盲肠的胆汁浓度不同，肠道提取物对弯曲杆菌体外生长的抑制作用与鸡肠各部分的总胆汁浓度密切相关。当接种到鸡体内时，野生型菌株最早在接种后第2天就在禽类体内定植，密度高达10(7)cfu/g粪便。相比之下，cmeABC突变体在整个研究过程中未能在任何接种的鸡身上定植。CmeABC突变体的最小感染剂量至少是野生型的2.6×10(4)倍。将cmeABC突变体与野生型cmeABC等位基因进行反式互补，完全恢复了突变株在含胆汁介质中的体外生长和体内定植，恢复到野生型菌株的水平。免疫印迹分析表明，CmeABC在实验感染空肠弯曲菌的雏鸡中得到了表达和免疫原性。总之，这些发现提供了令人信服的证据，证明CmeABC通过调节肠道对胆盐的抵抗，是成功在鸡中定植空肠弯曲菌所必需的。抑制CmeABC功能不仅可以控制抗生素耐药性，还可以防止病原性弯曲杆菌在体内定植。
CmeABC functions as a multidrug efflux pump contributing to the resistance of Campylobacter to a broad range of antimicrobials. In this study, we examined the role of CmeABC in bile resistance and its contribution to the adaptation of Campylobacter jejuni in the intestinal tract of the chicken, a natural host and a major reservoir for Campylobacter. Inactivation of cmeABC drastically decreased the resistance of Campylobacter to various bile salts. Addition of choleate (2 mM) in culture medium impaired the in vitro growth of the cmeABC mutants but had no effect on the growth of the wild-type strain. Bile concentration varied in the duodenum, jejunum, and cecum of chicken intestine, and the inhibitory effect of the intestinal extracts on the in vitro growth of Campylobacter was well correlated with the total bile concentration in the individual sections of chicken intestine. When inoculated into chickens, the wild-type strain colonized the birds as early as day 2 postinoculation with a density as high as 10(7) CFU/g of feces. In contrast, the cmeABC mutants failed to colonize any of the inoculated chickens throughout the study. The minimum infective dose for the cmeABC mutant was at least 2.6 x 10(4)-fold higher than that of the wild-type strain. Complementation of the cmeABC mutants with a wild-type cmeABC allelle in trans fully restored the in vitro growth in bile-containing media and the in vivo colonization to the levels of the wild-type strain. Immunoblotting analysis indicated that CmeABC is expressed and immunogenic in chickens experimentally infected with C. jejuni. Together, these findings provide compelling evidence that CmeABC, by mediating resistance to bile salts in the intestinal tract, is required for successful colonization of C. jejuni in chickens. Inhibition of CmeABC function may not only control antibiotic resistance but also prevent the in vivo colonization of pathogenic Campylobacter.