Department of Microbiology, Queen's Hospital, Barking, Havering and Redbridge Trust, Romford, Essex, UK.
Int J Infect Dis. 2010 Aug;14(8):e717-22. doi: 10.1016/j.ijid.2010.02.2247. Epub 2010 Jun 12.
To determine the utility of 'risk assessment' in selecting Mycobacterium tuberculosis isolates for rifampin resistance or rpoB genotyping compared to 'non-selectively' genotyping all isolates. Secondly, we examined the association between past treatment and drug resistance.
From January 2003 to December 2006, demographic, clinical, and laboratory data were prospectively collected on patients with laboratory-confirmed tuberculosis (TB). On the basis of past treatment for active TB infection or known exposure to drug-resistant TB, selected samples were sent to a mycobacterial reference laboratory for rpoB genotyping. A multivariable logistic regression model was developed to examine the association between past treatment and drug resistance, adjusted for other factors. Sensitivity, specificity, and negative and positive predictive values of past treatment as a predictor for drug resistance were determined.
There were 392 patient episodes of culture-proven TB. Thirty-three drug-resistant isolates were cultured from 30 patients: 29 (87.9%) were isoniazid-resistant, three (9.1%) were multidrug-resistant (MDR), and one (3.0%) was rifampin mono-resistant. One patient with isoniazid resistance developed recurrent disease, and two isolates, initially isoniazid-resistant, mutated and became MDR TB. Based on risk assessment, rpoB genotyping was performed on 19 samples, and two (10.5%) had mutations that predicted multiple drug resistance. Although for MDR TB, a past history of treatment predicted two out of three patients with acquired resistance, adjusted analysis did not demonstrate a significant association between previous treatment of active TB and drug resistance (odds ratio 1.5, 95% confidence interval (CI) 0.4-5.6). The positive predictive value of past treatment as a predictor for drug resistance was 12.0% (95% CI 2.6-31.2%).
Although numbers of MDR TB were too small to draw meaningful conclusions, past treatment may be useful in selecting samples for rpoB genotyping. Overall, previous treatment had a low positive predictive value for drug resistance in an area bordering East London.
确定“风险评估”在选择结核分枝杆菌分离物进行利福平耐药或 rpoB 基因分型方面的效用，与“非选择性”对所有分离物进行基因分型相比。其次，我们检查了既往治疗与耐药性之间的关联。
从 2003 年 1 月至 2006 年 12 月，前瞻性收集了实验室确诊的肺结核（TB）患者的人口统计学、临床和实验室数据。根据过去治疗活动性 TB 感染或已知接触耐药性 TB，选择一些样本送到分枝杆菌参考实验室进行 rpoB 基因分型。建立多变量逻辑回归模型，以检验既往治疗与耐药性之间的关联，并对其他因素进行调整。确定既往治疗作为耐药预测因子的敏感性、特异性、阴性和阳性预测值。
有 392 例培养阳性的 TB 患者。从 30 名患者中培养出 33 株耐药分离株：29 株（87.9%）为异烟肼耐药，3 株（9.1%）为耐多药（MDR），1 株（3.0%）为利福平单耐药。1 例异烟肼耐药患者发生复发性疾病，2 株异烟肼耐药的分离株发生突变，成为 MDR-TB。根据风险评估，对 19 个样本进行 rpoB 基因分型，其中 2 个（10.5%）有预测多种药物耐药的突变。虽然对于 MDR-TB，既往治疗史预测了 3 例获得性耐药中的 2 例，但调整分析并未显示既往治疗活动性 TB 与耐药性之间存在显著关联（比值比 1.5，95%置信区间[CI]0.4-5.6）。既往治疗作为耐药预测因子的阳性预测值为 12.0%（95%CI 2.6-31.2%）。
尽管 MDR-TB 的数量太少，无法得出有意义的结论，但既往治疗可能有助于选择 rpoB 基因分型的样本。总体而言，在与东伦敦接壤的地区，既往治疗对耐药性的阳性预测值较低。
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