Iakhiaeva Elena, Howard Susan T, Brown Elliott Barbara A, McNulty Steven, Newman Kristopher L, Falkinham Joseph O, Williams Myra, Kwait Rebecca, Lande Leah, Vasireddy Ravikiran, Turenne Christine, Wallace Richard J
Mycobacteria/Nocardia Research Laboratory, Department of Microbiology, University of Texas Health Science Center at Tyler, Tyler, Texas, USA.
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA.
J Clin Microbiol. 2016 Apr;54(4):891-901. doi: 10.1128/JCM.02409-15. Epub 2016 Jan 6.
"Mycobacterium aviumsubsp.hominissuis" is an important cause of pulmonary disease. It is acquired from environmental sources, but there is no methodology for large population studies. We evaluated the potential of variable-number tandem-repeat (VNTR) analysis. Clinical and household biofilmM. aviumisolates underwent molecular identification. Testing for IS901was done to separateM. aviumsubsp.aviumfromM. aviumsubsp.hominissuis VNTR types were defined using VNTR loci, and subtyping was performed using 3'hsp65and internal transcribed spacer (ITS) sequencing. Forty-nine VNTR types and eight subtypes ofM. aviumsubsp.hominissuis(IS901negative) were identified among 416 isolates ofM. aviumfrom 121 patients and 80 biofilm sites. Of those types, 67% were found only among patient isolates, 11% only among household water isolates, and 23% among both. Of 13 VNTR types that included ≥4 patients, the majority (61.5%) represented geographic clustering (same city). Most VNTR types with multiple patients belonged to the same 3'hsp65sequence code (sequevar). A total of 44 isolates belonging to fourM. aviumsubsp.hominissuisVNTR types (8%), including three with the rare Mav-F ITS sequence and 0/8 subspecies, produced amplicons with IS901PCR primers. By sequencing, all 44 amplicons were not IS901but ISMav6, which was recently observed in Japan but had not been previously described among U.S. isolates. VNTR analysis ofM. aviumsubsp.hominissuisisolates is easier and faster than pulsed-field gel electrophoresis. Seven VNTR loci separated 417 isolates into 49 types. No isolates ofM. aviumsubsp.aviumwere identified. The distributions of the VNTR copy numbers, the allelic diversity, and the low prevalence of ISMav6 differed from the findings for respiratory isolates reported from Japan.
“猪型分支杆菌”是肺部疾病的一个重要病因。它源自环境，但尚无针对大规模人群研究的方法。我们评估了可变数目串联重复序列（VNTR）分析的潜力。对临床和家庭生物膜中的鸟分枝杆菌分离株进行了分子鉴定。通过检测IS901来区分鸟分枝杆菌鸟型亚种和猪型分支杆菌。使用VNTR位点定义VNTR类型，并通过3'hsp65和内转录间隔区（ITS）测序进行亚型分析。在来自121名患者和80个生物膜位点的416株鸟分枝杆菌分离株中，鉴定出49种VNTR类型和8种猪型分支杆菌（IS901阴性）亚型。在这些类型中，67%仅在患者分离株中发现，11%仅在家用水分离株中发现，23%在两者中均有发现。在包括≥4名患者的13种VNTR类型中，大多数（61.5%）呈现地理聚集（同一城市）。大多数有多名患者的VNTR类型属于相同的3'hsp65序列编码（序列变体）。共有44株属于4种猪型分支杆菌VNTR类型（8%）的分离株，包括3株具有罕见的Mav-F ITS序列且0/8亚种的分离株，用IS901 PCR引物产生了扩增子。通过测序，所有44个扩增子均不是IS901而是ISMav6，这是最近在日本观察到的，但此前在美国分离株中未被描述。对猪型分支杆菌分离株进行VNTR分析比脉冲场凝胶电泳更容易、更快。7个VNTR位点将417株分离株分为49种类型。未鉴定出鸟分枝杆菌鸟型亚种的分离株。VNTR拷贝数的分布、等位基因多样性以及ISMav6的低流行率与日本报告的呼吸道分离株的结果不同。
