Department of Clinical Oncology, Pomeranian Medical University, Szczecin, Poland.
Department of Biology and Medical Parasitology, Pomeranian Medical University, Szczecin, Poland.
Parasit Vectors. 2021 Apr 14;14(1):200. doi: 10.1186/s13071-021-04681-x.
Blastocystis sp. is a common intestinal protozoan found worldwide. Based on gene analysis, 17 subtypes (STs, ST1-ST17) have been identified, 9 of which have been isolated from humans. Differences in clinical consequences may depend on differences among the STs. Here, we evaluated the prevalence of Blastocystis sp. in patients with colorectal cancer (CRC) compared to a control group and assessed the relationships between Blastocystis sp. infection and sex; age; and CRC grade, stage, and location.
The study included 107 CRC patients (41 women and 66 men, median age 65 years); 124 subjects without colorectal cancer or a history of oncological disease comprised the control group (55 women and 69 men, median age 63). Stool samples were collected from patients before oncological treatment and examined using light microscopy (iodine-stained smear). Additionally, PCR-based identification of Blastocystis sp. was performed in 95 stool samples from CRC patients and 76 stool samples from the control group.
Light microscopy showed that the prevalence of Blastocystis sp. was significantly higher in CRC patients than in the control group (12.15% and 2.42%, respectively; p = 0.0041). Multivariate analysis showed that the odds of Blastocystis sp. infection were fivefold higher in the CRC group than in the control group. PCR-based molecular examinations demonstrated that the proportion of patients infected with Blastocystis sp. was significantly higher in the CRC group than in the control group (12.63% and 2.63%, respectively; p = 0.023). The predominant ST in the CRC group was ST3, detected in nine patients (75%), followed by ST1 (2 patients, 16.7%) and ST2 (1 patient, 8.3%). No association was found between Blastocystis sp. infection and age, sex, or CRC stage, grade, or location.
The results showed that CRC was associated with an increased risk of opportunistic Blastocystis sp. infection, even before oncological treatment. To the best of our knowledge, this is the first report estimating the prevalence of Blastocystis sp. infection in CRC patients before oncological treatment in Europe.
芽囊原虫是一种常见的肠道原生动物，分布于世界各地。根据基因分析，已确定 17 种亚型（ST，ST1-ST17），其中 9 种已从人类中分离出来。临床后果的差异可能取决于 ST 之间的差异。在这里，我们评估了芽囊原虫在结直肠癌（CRC）患者中的流行率与对照组相比，并评估了芽囊原虫感染与性别、年龄以及 CRC 分级、分期和部位之间的关系。
该研究包括 107 例 CRC 患者（41 名女性和 66 名男性，中位年龄 65 岁）；124 名无结直肠癌或肿瘤病史的受试者为对照组（55 名女性和 69 名男性，中位年龄 63 岁）。在肿瘤治疗前采集患者的粪便样本，并用碘染色的涂片进行光镜检查。此外，对 95 例 CRC 患者和 76 例对照组的粪便样本进行基于 PCR 的芽囊原虫鉴定。
光镜检查显示，CRC 患者中芽囊原虫的流行率明显高于对照组（分别为 12.15%和 2.42%；p=0.0041）。多变量分析显示，CRC 组芽囊原虫感染的几率是对照组的五倍。基于 PCR 的分子检查显示，CRC 组感染芽囊原虫的患者比例明显高于对照组（分别为 12.63%和 2.63%；p=0.023）。CRC 组中主要的 ST 是 ST3，在 9 例患者（75%）中检测到，其次是 ST1（2 例，16.7%）和 ST2（1 例，8.3%）。芽囊原虫感染与年龄、性别或 CRC 分期、分级或部位无关。
结果表明，CRC 与机会性芽囊原虫感染的风险增加有关，甚至在肿瘤治疗之前。据我们所知，这是在欧洲首次报告估计 CRC 患者在肿瘤治疗前芽囊原虫感染的流行率。
