Cellular and Molecular Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran; Department of Microbiology, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
Cellular and Molecular Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran; Department of Microbiology, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
Int J Antimicrob Agents. 2017 Jul;50(1):119-122. doi: 10.1016/j.ijantimicag.2017.03.006. Epub 2017 May 19.
Early detection of Acinetobacter baumannii, an emerging pathogen in hospital settings, is of interest. The bla family had been used as a marker to detect A. baumannii. During an infection outbreak, 14 isolates produced a 1.7-kb PCR band instead of 353 bp for this marker. This work sought the reasons behind the increased marker size. Characterisation of isolates was done by API-20NE, gyrB multiplex PCR and 16S-23S rRNA ITS sequencing. The 1.7-kb band generated and the complete bla variant were sequenced to find the probable integrated element. Susceptibility testing to various antimicrobials was performed by microdilution. bla, metallo-β-lactamases (MBLs), the ISAba1 element and the presence of ISAba1 adjacent to bla were sought. rep-PCR, global clonal (GC) lineage determination and multilocus sequence typing (MLST) were performed to analyse the relationship among isolates. Isolates were characterised as Acinetobacter baumannii-calcoaceticus complex by API-20NE. gyrB multiplex PCR and 16S-23S ITS sequencing verified the isolates as A. baumannii. Sequencing of the 1.7-kb band revealed ISAba19 as the disrupting element. The bla variant was bla, which was elongated to 2.2 kb due to ISAba19. The bla family was found in 67% of isolates. MBL genes were not detected; however, ISAba1-bla was characterised in carbapenem-resistant isolates (53%; 8/15). Isolates were divided into three clusters by rep-PCR. All strains were ST2 and all but one belonged to GC II. Identification of A. baumannii based only on bla is not reliable. Besides bla, multiplex PCR of gyrB and rpoB could provide rapid and cost-effective results.
早期检测鲍曼不动杆菌，一种在医院环境中出现的新兴病原体，是有意义的。bla 家族一直被用作检测鲍曼不动杆菌的标记。在一次感染爆发中，14 株分离株产生了 1.7kb 的 PCR 条带，而不是该标记的 353bp。这项工作旨在寻找标记物大小增加的原因。通过 API-20NE、gyrB 多重 PCR 和 16S-23S rRNA ITS 测序对分离株进行了特征分析。对产生的 1.7kb 条带和完整的 bla 变体进行测序，以寻找可能的整合元件。通过微量稀释法对各种抗菌药物的敏感性进行了测试。寻找 bla、金属-β-内酰胺酶 (MBLs)、ISAba1 元件以及 bla 附近是否存在 ISAba1。通过重复序列 PCR（rep-PCR）、全球克隆（GC）谱系测定和多位点序列分型（MLST）分析分离株之间的关系。API-20NE 鉴定分离株为鲍曼不动杆菌-醋酸钙不动杆菌复合体。gyrB 多重 PCR 和 16S-23S ITS 测序证实分离株为鲍曼不动杆菌。1.7kb 条带的测序显示 ISAba19 为破坏元件。bla 变体为 bla，由于 ISAba19 的存在，延长至 2.2kb。bla 家族在 67%的分离株中被发现。未检测到 MBL 基因；然而，在耐碳青霉烯的分离株中（53%；8/15），ISAba1-bla 被表征。rep-PCR 将分离株分为三个群。所有菌株均为 ST2，除一株外均属于 GC II。仅基于 bla 鉴定鲍曼不动杆菌不可靠。除了 bla 之外，gyrB 和 rpoB 的多重 PCR 可以提供快速且具有成本效益的结果。
