Identification of dfrA14 in two distinct plasmids conferring trimethoprim resistance in Actinobacillus pleuropneumoniae.
Identification of dfrA14 in two distinct plasmids conferring trimethoprim resistance in Actinobacillus pleuropneumoniae.
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DOI：
10.1093/jac/dkv121
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发表时间：
2015-08
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通讯作者：
BRaDP1T Consortium
中科院分区：
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作者：
Bossé JT;Li Y;Walker S;Atherton T;Fernandez Crespo R;Williamson SM;Rogers J;Chaudhuri RR;Weinert LA;Oshota O;Holden MT;Maskell DJ;Tucker AW;Wren BW;Rycroft AN;Langford PR;BRaDP1T Consortium
本研究的目的是确定在英国猪胸膜肺炎放线杆菌分离株甲氧苄啶耐药的分布和遗传基础。检测了1998年至2011年期间收集的临床分离株对甲氧苄啶和磺胺的耐药性。甲氧苄啶耐药的遗传基础通过鸟枪WGS分析和随后的质粒分离和测序来确定。16个（共106个）A.胸膜肺炎分离株对甲氧苄啶（MIC >32 mg/L）和磺胺异恶唑（MIC ≥256 mg/L）均耐药，另有32株仅对磺胺异恶唑耐药（MIC ≥256 mg/L）。甲氧苄啶耐药分离株的基因组序列数据显示存在dfrA 14二氢叶酸还原酶基因。质粒序列在多个重叠群中的分布表明在不同的分离株中存在两种不同的含dfrA 14的质粒，这通过质粒分离和测序得到证实。这两种质粒编码动员基因，磺胺类药物耐药基因sul 2，以及dfrA 14插入到strA，链霉素耐药相关基因，虽然基因顺序不同的两种质粒。其中一个质粒进一步编码strB链霉素抗性相关基因。这是第一次描述可移动的质粒赋予甲氧苄啶耐药的A。并且据我们所知，dfrA 14在巴斯德菌科的任何成员中的首次报道。对甲氧苄氨嘧啶耐药基因dfrA 14进行了鉴定。胸膜肺炎分离株将有助于PCR筛选对这种重要抗菌剂的耐药性。
The objective of this study was to determine the distribution and genetic basis of trimethoprim resistance in Actinobacillus pleuropneumoniae isolates from pigs in England. Clinical isolates collected between 1998 and 2011 were tested for resistance to trimethoprim and sulphonamide. The genetic basis of trimethoprim resistance was determined by shotgun WGS analysis and the subsequent isolation and sequencing of plasmids. A total of 16 (out of 106) A. pleuropneumoniae isolates were resistant to both trimethoprim (MIC >32 mg/L) and sulfisoxazole (MIC ≥256 mg/L), and a further 32 were resistant only to sulfisoxazole (MIC ≥256 mg/L). Genome sequence data for the trimethoprim-resistant isolates revealed the presence of the dfrA14 dihydrofolate reductase gene. The distribution of plasmid sequences in multiple contigs suggested the presence of two distinct dfrA14-containing plasmids in different isolates, which was confirmed by plasmid isolation and sequencing. Both plasmids encoded mobilization genes, the sulphonamide resistance gene sul2, as well as dfrA14 inserted into strA, a streptomycin-resistance-associated gene, although the gene order differed between the two plasmids. One of the plasmids further encoded the strB streptomycin-resistance-associated gene. This is the first description of mobilizable plasmids conferring trimethoprim resistance in A. pleuropneumoniae and, to our knowledge, the first report of dfrA14 in any member of the Pasteurellaceae. The identification of dfrA14 conferring trimethoprim resistance in A. pleuropneumoniae isolates will facilitate PCR screens for resistance to this important antimicrobial.