Department of Parasitology, Medical Research Institute, University of Alexandria, 165 El Horreya Avenue, El Hadara, Alexandria, Egypt.
Department of Medical Laboratory, Faculty of Allied Medical Sciences, Pharos University, Alexandria, Egypt.
Acta Parasitol. 2021 Jun;66(2):346-353. doi: 10.1007/s11686-020-00283-2. Epub 2020 Sep 29.
Microsporidia infection was originally described as an immunocompromised associated pathogen. Limitations to correct microscopic diagnosis of microsporidia include size of the organism presenting a challenge even to a highly competent laboratory expert.
The present study aimed to detect microsporidia infection among leukemic children. The performance of modified trichrome stain and PCR in the diagnosis of microsporidia was evaluated with further speciation.
Stool samples of 100 leukemic children on chemotherapy were examined microscopically for microsporidia. DNA was extracted from all samples. Amplification was performed by conventional and nested PCR. Sequencing of amplified products was performed on unspeciated samples.
Microsporidia were detected in 23% of the children by MTS and 29% by PCR. The 29 positive samples were subjected to PCR for speciation. Enterocytozoon bieneusi was found to predominate in 20 cases, Encephalitozoon intestinalis in three cases, two cases had co-infection, and the remaining four samples were not amplified with either E. bieneusi or E. intestinalis specific primers. By DNA sequencing of the unspeciated samples, three samples shared high homology with Encephalitozoon hellem and one sample with Encephalitozoon cuniculi. Referring to PCR as a gold standard, MTS exhibited 72.4% sensitivity and 97.2% specificity with 90% accuracy. Among a number of studied variables, diarrhea and colic were significantly associated with microsporidia infection when diagnosed by either technique.
The use of sensitive and discriminative molecular tools will contribute to determining the true prevalence of microsporidiosis and possibly their potential transmission source depending on species identification.
微孢子虫感染最初被描述为一种与免疫功能低下相关的病原体。即使是经验丰富的实验室专家，由于该生物体的大小，对微孢子虫的正确显微镜诊断也存在局限性。
本研究旨在检测接受化疗的白血病儿童中的微孢子虫感染。评估改良三色染色和 PCR 在微孢子虫诊断中的性能，并进一步进行种系鉴定。
对 100 名接受化疗的白血病儿童的粪便样本进行微孢子虫检查。从所有样本中提取 DNA。通过常规和巢式 PCR 进行扩增。对未鉴定的样本进行测序。
MTS 检测到 23%的儿童存在微孢子虫，PCR 检测到 29%的儿童存在微孢子虫。对 29 个阳性样本进行 PCR 种系鉴定。发现肠微孢子虫在 20 例中占优势，脑炎微孢子虫在 3 例中占优势，2 例存在混合感染，其余 4 个样本未扩增出肠微孢子虫或脑炎微孢子虫特异性引物。通过未鉴定样本的 DNA 测序，有 3 个样本与脑炎微孢子虫高度同源，1 个样本与兔脑炎微孢子虫同源。以 PCR 为金标准，MTS 的灵敏度为 72.4%，特异性为 97.2%，准确性为 90%。在研究的多个变量中，腹泻和绞痛在两种技术诊断时均与微孢子虫感染显著相关。
使用敏感和有区别的分子工具将有助于确定微孢子虫病的真实流行率，并根据物种鉴定确定其潜在的传播源。
