摘要

类鼻疽伯克霍尔德杆菌Bp1651对通常对治疗类鼻疽病有效的几类抗生素具有抗性，包括四环素类，磺胺类和β-内酰胺类，如青霉素（阿莫西林 - 克拉维酸），头孢菌素类（头孢他啶）和碳青霉烯类（亚胺培南和美罗培南） 。我们对Bp1651基因组进行测序，组装和注释，并使用易感菌株的比较基因组分析，注释的关键词搜索，公开可用的抗微生物药耐药性预测工具和已发表的报告分析了序列。鉴定出Bp1651序列中超过100个基因可能有助于抗微生物药物耐药性。最值得注意的是，我们在penA中发现了三个先前未表征的点突变，它们编码A类β-内酰胺酶，并且之前与β-内酰胺类抗生素的耐药性有关。突变导致氨基酸改变T147A，D240G和V261I。当单独引入到选择药剂排除的类鼻疽Bp82菌株中时，发现D240G有助于头孢他啶耐药性，并且T147A有助于阿莫西林 - 克拉维酸和亚胺培南耐药性。这项研究提供了第一个证据表明，penA突变可能会改变类鼻疽伯乐菌对碳青霉烯类药物的易感性。另一个感兴趣的突变是影响二氢叶酸还原酶基因folA的点突变，这可能解释了该菌株的甲氧苄啶抗性。 Bp1651易受氨基糖苷类药物的影响，这可能是由于amrB基因 - AmrAB-OprA外排泵的转运子亚单位的移码。这些发现扩大了penA的作用，包括对碳青霉烯类药物的耐药性，并可能有助于开发预测抗菌药物耐药性的分子诊断学，并为类鼻疽病的治疗提供指导。

Burkholderia pseudomallei Bp1651 is resistant to several classes of antibiotics that are usually effective for treatment of melioidosis, including tetracyclines, sulfonamides, and β-lactams such as penicillins (amoxicillin-clavulanic acid), cephalosporins (ceftazidime), and carbapenems (imipenem and meropenem). We sequenced, assembled, and annotated the Bp1651 genome and analyzed the sequence using comparative genomic analyses with susceptible strains, keyword searches of the annotation, publicly available antimicrobial resistance prediction tools, and published reports. More than 100 genes in the Bp1651 sequence were identified as potentially contributing to antimicrobial resistance. Most notably, we identified three previously uncharacterized point mutations in penA, which codes for a class A β-lactamase and was previously implicated in resistance to β-lactam antibiotics. The mutations result in amino acid changes T147A, D240G, and V261I. When individually introduced into select agent-excluded B. pseudomallei strain Bp82, D240G was found to contribute to ceftazidime resistance and T147A contributed to amoxicillin-clavulanic acid and imipenem resistance. This study provides the first evidence that mutations in penA may alter susceptibility to carbapenems in B. pseudomallei. Another mutation of interest was a point mutation affecting the dihydrofolate reductase gene folA, which likely explains the trimethoprim resistance of this strain. Bp1651 was susceptible to aminoglycosides likely because of a frameshift in the amrB gene, the transporter subunit of the AmrAB-OprA efflux pump. These findings expand the role of penA to include resistance to carbapenems and may assist in the development of molecular diagnostics that predict antimicrobial resistance and provide guidance for treatment of melioidosis.

http://aac.asm.org/content/61/6/e00010-17.short