Gopinath K, Kumar S, Singh S
Division of Clinical Microbiology, Department of Laboratory Medicine, All India Institute of Medical Sciences (AIIMS), Ansari Nagar, New Delhi, India.
Eur J Clin Microbiol Infect Dis. 2008 Jun;27(6):423-31. doi: 10.1007/s10096-007-0450-x. Epub 2008 Jan 10.
The use of automated blood cultures system, such as MB/BacT, has provided a novel opportunity for laboratories to diagnose mycobacteremia in HIV-infected patients. However, no such study has been carried out in India so far. This prospective study was conducted on 52 HIV-positive patients with suspected tuberculosis who were referred to our tertiary care hospital in New Delhi. In these patients, the prevalence of mycobacteremia was evaluated using the MB/BacT automated culture system (bioMérieux, France). Twenty-seven HIV-negative but suspected tuberculosis patients were also included for comparison. Mycobacteria could be isolated from sputa or fecal samples of 20 HIV-positive patients (38.4%), and in nine (45%) of these 20 cases, mycobacteria could also be isolated simultaneously from their blood specimens. In the remaining 32 patients, all relevant non-hematological clinical samples remained negative for mycobacteria, but the pathogen could be detected from the blood samples of seven (21.87%) of these 32 patients. Therefore, only 25 (48%) clinically suspected patients remained negative in both Löwenstein-Jensen (L-J) and MB/BacT culture methods, and 12 of these responded to anti-tubercular treatment, while in the rest either non-tubercular diagnosis was established or they were lost to follow-up. The study revealed that low CD+(4) counts and poor or no reactivity to purified protein derivative (PPD) were the best clinical predictors for the occurrence of mycobacteremia in HIV-positive patients. Of the 16 isolates from blood, 13 were diagnosed as Mycobacterium tuberculosis and one each were identified as M. avium, M. kansasii, and a mixed infection of M. tuberculosis and M. avium complex. The prevalence rate of mycobacteremia was significantly low (11.1%) in HIV-negative patients. In conclusion, this study showed that blood culture could be an important adjunct investigation for confirming the clinical diagnosis of tuberculosis in HIV-positive patients.
使用自动化血培养系统，如MB/BacT，为实验室诊断HIV感染患者的分枝杆菌血症提供了新的契机。然而，迄今为止印度尚未开展此类研究。本前瞻性研究针对52例疑似结核病的HIV阳性患者展开，这些患者被转诊至新德里的我们的三级护理医院。在这些患者中，使用MB/BacT自动化培养系统（法国生物梅里埃公司）评估分枝杆菌血症的患病率。还纳入了27例HIV阴性但疑似结核病的患者作为对照。20例HIV阳性患者（38.4%）的痰液或粪便样本中可分离出分枝杆菌，在这20例中的9例（45%）中，其血液标本中也可同时分离出分枝杆菌。在其余32例患者中，所有相关非血液学临床样本的分枝杆菌检测均为阴性，但在这32例患者中的7例（21.87%）血液样本中可检测到病原体。因此，仅25例（48%）临床疑似患者在罗氏（L-J）和MB/BacT培养方法中均为阴性，其中12例对抗结核治疗有反应，而其余患者要么确诊为非结核性疾病，要么失访。研究表明，CD+(4)细胞计数低以及对纯化蛋白衍生物（PPD）反应差或无反应是HIV阳性患者发生分枝杆菌血症的最佳临床预测指标。从血液中分离出的16株菌株中，13株被诊断为结核分枝杆菌，1株分别被鉴定为鸟分枝杆菌、堪萨斯分枝杆菌，以及1例结核分枝杆菌和鸟分枝杆菌复合群的混合感染。HIV阴性患者的分枝杆菌血症患病率显著较低（11.1%）。总之，本研究表明血培养可能是确诊HIV阳性患者结核病临床诊断的一项重要辅助检查。
