Genetic Environments of the rmtA Gene in Pseudomonas aeruginosa Clinical Isolates
Genetic Environments of the rmtA Gene in Pseudomonas aeruginosa Clinical Isolates
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DOI：
10.1128/aac.48.6.2069-2074.2004
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发表时间：
2004-06
影响因子：
4.9
通讯作者：
Kunikazu Yamane;Y. Doi;K. Yokoyama;T. Yagi;H. Kurokawa;N. Shibata;K. Shibayama;H. Kato;Y. Arakawa
中科院分区：
文献类型：
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作者：
Kunikazu Yamane;Y. Doi;K. Yokoyama;T. Yagi;H. Kurokawa;N. Shibata;K. Shibayama;H. Kato;Y. Arakawa
摘要自1997年以来，从日本5个县的7家医院的临床标本中分离出9株对各种氨基糖苷类抗生素具有高度耐药性的铜绿假单胞菌。这些菌株携带新鉴定的16 S rRNA甲基化酶基因（rmtA）。当rmtA基因探针与用EcoRI消化的9个菌株的基因组DNA杂交时，观察到两种不同的模式。分别对AR-2和AR-11菌株的11.1-kb和15.8-kb的rmtA基因区域进行测序和比较。在AR-2菌株中，一个转座酶基因样序列（序列1）和一个可能的tRNA核糖基转移酶基因（orfA）位于rmtA的上游，和一个Na+/H+反向转运蛋白基因样序列（序列2）被鉴定的rmtA的下游。这个6.2-kbp的插入片段（rmtA基因座）两侧是262-bp的κγ元件。orfQ基因的一部分相邻的反向重复序列被发现以外的rmtA位点。AR-11株中存在rmtA基因和序列2，但orfA基因5′端被截短，替换为IS 6100。在AR-11菌株中，rmtA基因两侧各存在一个orfQ-orfI区域。rmtA基因的G+C含量约为55%，并且由于新鉴定的rmtA基因很可能由一些移动的遗传元件如Tn 5041介导，因此rmtA基因的进一步传播可能在不久的将来成为实际的临床问题。
ABSTRACT Nine Pseudomonas aeruginosa strains showing very high levels of resistance to various aminoglycosides have been isolated from clinical specimens in seven separate Japanese hospitals in five prefectures since 1997. These strains harbor the newly identified 16S rRNA methylase gene (rmtA). When an rmtA gene probe was hybridized with genomic DNAs of the nine strains digested with EcoRI, two distinct patterns were observed. The 11.1- and 15.8-kb regions containing the rmtA genes of strains AR-2 and AR-11, respectively, were sequenced and compared. In strain AR-2, a transposase gene-like sequence (sequence 1) and a probable tRNA ribosyltransferase gene (orfA) were located upstream of rmtA, and a Na+/H+ antiporter gene-like sequence (sequence 2) was identified downstream of rmtA. This 6.2-kbp insert (the rmtA locus) was flanked by 262-bp κγ elements. Part of the orfQ gene adjacent to an inverted repeat was found outside of the rmtA locus. In strain AR-11, the rmtA gene and sequence 2 were found, but the 5′ end of the orfA gene was truncated and replaced with IS6100. An orfQ-orfI region was present on each side of the rmtA gene in strain AR-11. The G+C content of the rmtA gene was about 55%, and since the newly identified rmtA gene may well be mediated by some mobile genetic elements such as Tn5041, further dissemination of the rmtA gene could become an actual clinical problem in the near future.