The Identification of Intrinsic Chloramphenicol and Tetracycline Resistance Genes in Members of the Bacillus cereus Group (sensu lato).
The Identification of Intrinsic Chloramphenicol and Tetracycline Resistance Genes in Members of the Bacillus cereus Group (sensu lato).
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DOI：
10.3389/fmicb.2016.02122
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发表时间：
2016
影响因子：
5.2
通讯作者：
Harwood CR
中科院分区：
文献类型：
--
作者：
Glenwright H;Pohl S;Navarro F;Miro E;Jiménez G;Blanch AR;Harwood CR
东洋芽孢杆菌菌株BCT-7112 T（NCIMB 14858 T）已被广泛用作动物营养添加剂超过30年，没有不良致突变作用的报道。然而，该菌株对氯霉素和四环素具有耐药性，一般认为不建议将能够转移到其他细菌菌株的耐药性决定簇引入食物链，从而增加牲畜物种胃肠系统中的此类决定簇库。因此，我们表征了该菌株及其近亲的抗性表型，以确定它们是否是最近起源的，因此可能是可传播的。为此，我们确定了负责氯霉素（catQ）和四环素（tetM）抗性的基因，并证实了在B的其他成员中存在同源物。东洋属分类单位。出乎意料的是，编码这些基因的密切相关的菌株没有表现出氯霉素和四环素耐药表型。为了了解行为上的差异，我们将这些基因及其上游调控区克隆并表达到枯草芽孢杆菌中。数据显示，这些基因编码功能蛋白，但从其天然启动子中表达效率低下。B。toyonensis是蜡状芽孢杆菌组（广义上）的分类单位成员。因此，我们扩展了分析，以确定同源氯霉素和四环素耐药基因在这组内的其他物种中存在的程度。该分析显示，同源基因存在于B内几乎所有代表性物种中。蜡状群（广义）。已知的转座元件的情况下，他们被发现在相同的基因组位置的观察，表明这些氯霉素和四环素抗性基因是古老的起源和固有的这个分类组，而不是最近收购。在这种情况下，我们讨论什么是和不是内在基因的定义，这是一个问题，是一个根本的重要性，监管机构，动物饲料和相关行业。
Bacillus toyonensis strain BCT-7112T (NCIMB 14858T) has been widely used as an additive in animal nutrition for more than 30 years without reports of adverse toxigenic effects. However, this strain is resistant to chloramphenicol and tetracycline and it is generally considered inadvisable to introduce into the food chain resistance determinants capable of being transferred to other bacterial strains, thereby adding to the pool of such determinants in the gastro-enteric systems of livestock species. We therefore characterized the resistance phenotypes of this strain and its close relatives to determine whether they were of recent origin, and therefore likely to be transmissible. To this end we identified the genes responsible for chloramphenicol (catQ) and tetracycline (tetM) resistance and confirmed the presence of homologs in other members of the B. toyonensis taxonomic unit. Unexpectedly, closely related strains encoding these genes did not exhibit chloramphenicol and tetracycline resistance phenotypes. To understand the differences in the behaviors, we cloned and expressed the genes, together with their upstream regulatory regions, into Bacillus subtilis. The data showed that the genes encoded functional proteins, but were expressed inefficiently from their native promoters. B. toyonensis is a taxonomic unit member of the Bacillus cereus group (sensu lato). We therefore extended the analysis to determine the extent to which homologous chloramphenicol and tetracycline resistance genes were present in other species within this group. This analysis revealed that homologous genes were present in nearly all representative species within the B. cereus group (sensu lato). The absence of known transposition elements and the observations that they are found at the same genomic locations, indicates that these chloramphenicol and tetracycline resistance genes are of ancient origin and intrinsic to this taxonomic group, rather than recent acquisitions. In this context we discuss definitions of what are and are not intrinsic genes, an issue that is of fundamental importance to both Regulatory Authorities, and the animal feed and related industries.
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影响因子：
5.2
作者：
Perry JA;Wright GD
通讯作者：
Wright GD
影响因子：
3.2
作者：
BECK, CF;MUTZEL, R;MULLER, W
通讯作者：
MULLER, W
影响因子：
3.2
作者：
Britton, RA;Eichenberger, P;Grossman, AD
通讯作者：
Grossman, AD
影响因子：
3.4
作者：
Böhm ME;Huptas C;Krey VM;Scherer S
通讯作者：
Scherer S
DOI：
10.1099/ijs.0.060301-0
发表时间：
2014-01-01
影响因子：
2.8
作者：
Oren，Aharon;Garrity，George M.
通讯作者：
Garrity，George M.