Evaluation of three methods for detecting Blastocystis hominis in HIV/AIDS patients

Abstract

Objective Three methods for detecting Blastocystis hominis in the feces of HIV / AIDS patients were evaluated to provide a basis for epidemiological investigation methods for the infection of B. hominis.

Methods The feces of HIV/AIDS patients treated with antiviral therapy and VCT (Voluntary Counseling and Testing) were collected and then detected by physiological saline method of direct smear, iodine method of direct smear and culture in vitro. The positive results of B. hominis were determined by PCR.

Results A total of 505 fecal samples were tested, the highest positive rate among the three methods was culture in vitro (3.96%, 20/505), followed by iodine method of direct smear (2.77%, 14/505) and physiological saline method of direct smear (2.57%, 13 / 505); 22 positive results(4.36%, 22 / 505) were detected by PCR. There was no significant difference in the positive rates of the four methods ( P>0.05). Using PCR as a reference method, the specificity and the positive predictive value of the three methods were the same, 100.00% (483/483). The sensitivity of 86.36% culture method in vitro was significantly higher than that of 54.55% in physiological saline smear method and 59.09% in iodine method of direct smear. The negative predictive value was 99.38%, the coincidence rate of 99.41% and the yodon index was 0.86 of culture method in vitro, which were slightly higher than that of physiological saline smear method, 97.97%, 98.02%, 0.55, and iodine method of direct smear 98.17%, 98.22%, 0.59, respectively.

Conclusion The method of culture in vitro has the highest sensitivity and is suitable for the epidemiological investigation of infection with B. hominis.

Abstract

摘要： 目的 对 HIV/AIDS 患者粪便中人芽囊原虫的 3 种检测方法进行评价, 为开展大规模人芽囊原虫感染的流行 病学调查提供适合的方法。 方法 采集抗病毒治疗及艾滋病自愿咨询检测 (VCT) 的 HIV/AIDS 患者粪便, 采用生理盐 水涂片法、碘液染色法和体外培养法检测人芽囊原虫, 同时通过对 PCR 产物测序确定人芽囊原虫阳性结果。 结果 共 检测调查对象粪样 505 份, 生理盐水涂片法、碘液染色法和体外培养法阳性率分别为 2.57% (13/505)、2.77%(14/505) 和 3.96% (20/505), PCR 扩增产物测出22份人芽囊原虫序列, 阳性率为4.36%(22/505), 4 种方法阳性率差异无统计学意义 ( P>0.05)。以 PCR 作为参比方法, 3 种方法的特异度和阳性预测值一致, 均为 100.00% (483/483) ；体外培养法的灵敏度 86.36% 明显高于生理盐水涂片法 54.55%和碘液染色法 59.09%, 体外培养法阴性预测值99.38%、符合率 99.41% 和约登 指数 0.86 均略高于生理盐水涂片法 97.97%、98.02%、0.55 及碘液染色法 98.17%、98.22%、0.59。 结论 人芽囊原虫体外 培养法灵敏度最高, 适合基层开展大规模人芽囊原虫感染的流行病学调查。