Frothingham R, Wilson K H
Infectious Disease Section, Durham VA Medical Center, NC 27705.
J Infect Dis. 1994 Feb;169(2):305-12. doi: 10.1093/infdis/169.2.305.
Phylogenetic analysis of nucleotide sequence data is widely used for viral epidemiology. To explore its use in bacterial strain differentiation, the variable 16S-23S rDNA internal transcribed spacer (ITS) in 24 clinical isolates originally identified as Mycobacterium avium complex (MAC) was sequenced. Three isolates had an identical sequence that differed greatly from the rest. They belonged to the recently described Mycobacterium celatum. The 21 MAC clinical isolates gave 6 ITS sequences, each defining a sequevar. Thirteen isolates from 11 AIDS patients with disseminated MAC disease belonged to 2 sequevars, which differed in ITS sequence by 1 nucleotide. In contrast, 7 pulmonary-source MAC isolates were genetically more diverse. They belonged to 4 sequevars, which differed from each other by 6-20 nucleotides and from the disseminated disease-associated sequevars by at least 12 nucleotides. The single urine MAC isolate had the same sequence as 1 of the pulmonary isolates. Because the disseminated disease-associated MAC strains were distinct by ITS sequence analysis, it should be possible to develop a molecular assay to detect them directly in clinical specimens or in environmental samples. Molecular phylogeny at the strain level may be widely useful in studies of bacterial epidemiology and virulence.
核苷酸序列数据的系统发育分析广泛应用于病毒流行病学。为探索其在细菌菌株鉴别中的应用，对最初鉴定为鸟分枝杆菌复合群（MAC）的24株临床分离株的可变16S - 23S rDNA内转录间隔区（ITS）进行了测序。有3株分离株具有相同的序列，与其他分离株差异很大。它们属于最近描述的塞拉分枝杆菌。21株MAC临床分离株产生了6种ITS序列，每种序列定义一个序列变种。来自11例播散性MAC病艾滋病患者的13株分离株属于2个序列变种，其ITS序列相差1个核苷酸。相比之下，7株肺源MAC分离株在基因上更为多样。它们属于4个序列变种，彼此相差6 - 20个核苷酸，与播散性疾病相关的序列变种至少相差12个核苷酸。单一的尿液MAC分离株与1株肺源分离株具有相同的序列。由于通过ITS序列分析，播散性疾病相关的MAC菌株是不同的，因此应该有可能开发一种分子检测方法，直接在临床标本或环境样本中检测它们。菌株水平的分子系统发育在细菌流行病学和毒力研究中可能具有广泛的用途。
