Identification of fusB-Mediated Fusidic Acid Resistance Islands in Staphylococcus epidermidis Isolates
Identification of fusB-Mediated Fusidic Acid Resistance Islands in Staphylococcus epidermidis Isolates
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DOI：
10.1128/aac.00592-11
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发表时间：
2011-12-01
影响因子：
4.9
通讯作者：
Teng, Lee-Jene
中科院分区：
文献类型：
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作者：
Chen, Hsiao-Jan;Tsai, Jui-Chang;Teng, Lee-Jene
为了解耐夫西地酸表皮葡萄球菌中fusB基因的高流行率，对34株菌株的耐药基因进行了分析。首先，aj1-LP-fusB区域的序列分析表明，至少存在三种类型。ⅰ型含有全长aj1，ⅱ型含有从93 - 421核苷酸位置截断的部分aj1，ⅲ型含有较短的aj1，仅保留最后37 bp。aj1型和aj1型菌株对氟西地酸（8 ~ 32 μ g/ml）的抗性水平略高于aj1型菌株（4 ~ 16 μ g/ml）。随后对4株携带不同类型aj1- lb -fusB区域的分离株的fusB侧翼区域进行测序，发现fusB基因均位于噬菌体相关抗性岛（RIs）上，分别为SeRIfusB-2793、SeRIfusB-704、SeRIfusB-5907和SeRIfusB-7778。其中，三个岛（SeRIfusB-2793、SeRIfusB-704和SeRIfusB-5907）位于groEL下游（基于金黄色葡萄球菌全基因组序列对应于44分钟位置），一个岛（SeRIfusB-7778）位于rpsR下游（对应于8分钟位置）。所有的RIs都被插入到整合酶识别的att位点。在34株分离株中，fusB RIs的插入位点大部分（28/ 34,82%）位于groEL下游，2个位于rpsR下游，但仍有4个未确定。脉冲型分布表明，含fusb的表皮葡萄球菌分离株具有异质性。由此可见，表皮葡萄球菌fusB抗性决定因子与噬菌体相关RIs高度相关。这是表皮葡萄球菌中fusbri的首次报道。
To understand the high prevalence of fusB genes in fusidic acid-resistant Staphylococcus epidermidis, analysis of resistance elements in 34 isolates was performed. First, sequence analysis of the aj1-LP-fusB region indicated that at least three types were present. Type I contained full-length aj1, type II contained a partial aj1 truncated from nucleotide position 93 to 421, and type III contained a more truncated aj1 that retained only the last 37 bp. Isolates with type I or type II aj1 displayed slightly higher levels of resistance to fusidic acid (MICs, 8 to 32 mu g/ml) than did those with type III aj1 (MICs, 4 to 16 mu g/ml). Subsequent sequencing of the flanking regions of fusB from four selected isolates carrying different types of aj1-LP-fusB regions revealed that the fusB genes were all located on phage-related resistance islands (RIs), referred to as SeRIfusB-2793, SeRIfusB-704, SeRIfusB-5907, and SeRIfusB-7778, respectively. Among them, three islands (SeRIfusB-2793, SeRIfusB-704, and SeRIfusB-5907) were located downstream of groEL (corresponding to the 44-min position based on Staphylococcus aureus whole genomic sequences), and one (SeRIfusB-7778) was located downstream of rpsR (corresponding to the 8-min position). All of the RIs were inserted into integrase-recognized att sites. Among 34 isolates, the insertion sites of fusB RIs were mostly (28/34, 82%) located downstream of groEL and two were located downstream of rpsR, but four remained unidentified. The pulsotype distribution indicated that fusB-containing S. epidermidis isolates were heterogeneous. In conclusion, the fusB resistance determinant in S. epidermidis was highly associated with phage-related RIs. This is the first report of fusB RI in S. epidermidis.