Multiphasic approach reveals genetic diversity of environmental and patient isolates of Mycobacterium mucogenicum and Mycobacterium phocaicum associated with an outbreak of Bacteremias at a texas hospital
Multiphasic approach reveals genetic diversity of environmental and patient isolates of Mycobacterium mucogenicum and Mycobacterium phocaicum associated with an outbreak of Bacteremias at a texas hospital
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DOI：
10.1128/aem.02476-07
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发表时间：
2008-04-01
影响因子：
4.4
通讯作者：
Srinivasan, Arjun
中科院分区：
文献类型：
--
作者：
Cooksey, Robert C.;Jhung, Michael A.;Srinivasan, Arjun
2006年3月至5月间，德克萨斯州一家医院利用荧光高效液相色谱法对霉菌酸进行分析，在住院肿瘤患者中发现了5例黏液原分枝杆菌血液感染。从血液培养中分离的菌株与从与该病房相关的环境场所或水中分离的16株菌株进行了比较。通过hsp65、16S rRNA和rpoB基因测序、hsp65 PCR酶切分析和分子分型方法（包括重复元件PCR、随机扩增多态性DNA PCR和大酶切片段的脉冲场凝胶电泳（PFGE））对这些分离物进行了进一步的鉴定。所有鉴定和分型方法均证实，5株患者分离株中有3株为粘膜原分枝杆菌，属于单一聚类。经rpoB序列分析，其余两株患者分离株为不同的phocaicum分枝杆菌菌株。其中一种与从患者房间的手淋浴拭子中提取的环境分离株相匹配，而临床分离的粘膜原分枝杆菌没有一种与环境菌株相匹配。其余15株环境分离株中，11株为mucogenicum， 4株为phocaicum，经分型分析均无亲缘关系。虽然16S rRNA基因序列与所有14株粘膜原分枝杆菌分离株相匹配，但hsp65和rpoB各有2个序列，7个PCR分型模式和12个PFGE模式。7株phocaicum分离株中有3株16S rRNA序列、2株hsp65序列、2株rpoB序列、6株PCR分型和6株PFGE序列。此次暴发是由phocaicum引起的导管相关性菌血症的第一例，也是美国医院临床分离株的第一例报告。该调查强调了分枝杆菌现有分型方法的重要差异，并证明了这些生物的遗传多样性，即使在狭窄的时间和空间范围内。
Between March and May 2006, a Texas hospital identified five Mycobacterium mucogenicum bloodstream infections among hospitalized oncology patients using fluorescence high-performance liquid chromatography analysis of mycolic acids. Isolates from blood cultures were compared to 16 isolates from environmental sites or water associated with this ward. These isolates were further characterized by hsp65, 16S rRNA, and rpoB gene sequencing, hsp65 PCR restriction analysis, and molecular typing methods, including repetitive element PCR, random amplified polymorphic DNA PCR, and pulsed-field gel electrophoresis (PFGE) of large restriction fragments. Three of five patient isolates were confirmed as M. mucogenicum and were in a single cluster as determined by all identification and typing methods. The remaining two patient isolates were identified as different strains of Mycobacterium phocaicum by rpoB sequence analysis. One of these matched an environmental isolate from a swab of a hand shower in the patient's room, while none of the clinical isolates of M. mucogenicum matched environmental strains. Among the other 15 environmental isolates, 11 were identified as M. mucogenicum and 4 as M. phocaicum strains, all of which were unrelated by typing methods. Although the 16S rRNA gene sequences matched for all 14 M. mucogenicum isolates, there were two each of the hsp65 and rpoB sequevars, seven PCR typing patterns, and 12 PFGE patterns. Among the seven M. phocaicum isolates were three 16S rRNA sequevars, two hsp65 sequevars, two rpoB sequevars, six PCR typing patterns, and six PFGE patterns. This outbreak represents the first case of catheter-associated bacteremia caused by M. phocaicum and the first report of clinical isolates from a U.S. hospital. The investigation highlights important differences in the available typing methods for mycobacteria and demonstrates the genetic diversity of these organisms even within narrow confines of time and space.