García-Elorriaga Guadalupe, Degollado-Estrada Edgar, Villagómez-Ruiz Alfredo, Cortés-Torres Nancy, Arreguín-Reséndiz Lilián, Del Rey-Pineda Guillermo, González-Bonilla César
Unidad de Investigación Médica en Inmunología e Infectología, Hospital de Infectología, Centro Médico Nacional La Raza, Instituto Mexicano del Seguro Social, Ciudad de México, México.
Rev Med Inst Mex Seguro Soc. 2016 Mar-Apr;54(2):170-5.
The aim of this study is to differentially identify MAC by PCR in patients with AIDS and disseminated mycobacteriosis.
A cross sectional study was conducted in Mexico to identify MAC by Molecular Biology. Two sets of primers were synthesized: MAV and MIN, for M. avium and M. intracellulare, respectively. Whole-cell DNAs obtained from 29 clinical isolates and clinical serum specimens from other 24 patients with AIDS and disseminated mycobacterial infection were extracted and amplified by PCR with the MAV and MIN primers. The MAV and MIN primers each amplified one highly specific 1.3-kb segment of the homologous DNA, respectively.
Twenty-nine DNAs from MAC clinical isolates identified by Gen-Probe AccuProbes were amplified with the MAV primers. Of the 24 clinical samples, 3 were positive for M. avium and 6 for M. tuberculosis.
Our results demonstrated that PCR technique could be applied for the differentiation of M. avium and M. intracellulare by specific 16S rRNA primers. In patients with advanced stage AIDS and in whom disseminated mycobacteriosis is suspected, the presence of anemia (even with negative cultures), elevated alkaline phosphatase and a median CD4 count of 15.9/mL, the diagnosis of infection by MAC should be strongly considered; we suggest that in accordance with our findings, a more precise stratification of patients in terms of their CD4 T cell counts is warranted.
本研究旨在通过聚合酶链反应（PCR）对艾滋病患者和播散性分枝杆菌病患者中的鸟分枝杆菌复合体（MAC）进行鉴别诊断。
在墨西哥开展了一项横断面研究，采用分子生物学方法鉴定MAC。合成了两组引物：MAV和MIN，分别用于扩增鸟分枝杆菌和胞内分枝杆菌。从29株临床分离株以及另外24例艾滋病合并播散性分枝杆菌感染患者的临床血清标本中提取全细胞DNA，并用MAV和MIN引物进行PCR扩增。MAV和MIN引物分别扩增出一段高度特异的1.3 kb同源DNA片段。
用Gen-Probe AccuProbes鉴定的29份MAC临床分离株的DNA能用MAV引物扩增。在24份临床样本中，3份鸟分枝杆菌阳性，6份结核分枝杆菌阳性。
我们的结果表明，PCR技术可通过特异性16S rRNA引物用于鉴别鸟分枝杆菌和胞内分枝杆菌。对于晚期艾滋病且怀疑有播散性分枝杆菌病的患者，若存在贫血（即使培养结果为阴性）、碱性磷酸酶升高且CD4细胞计数中位数为15.9/mL，则应高度考虑MAC感染的诊断；我们建议，根据我们的研究结果，有必要根据CD4 T细胞计数对患者进行更精确的分层。
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