Department of Internal Medicine, Iran University of Medical Sciences, Tehran, Iran.
Antimicrobial Resistance Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.
BMC Infect Dis. 2024 Nov 27;24(1):1355. doi: 10.1186/s12879-024-10235-0.
Parasitic infections, especially opportunistic infections, are important issues for immunocompromised patients, including cancer patients. In this study, the prevalence of intestinal protozoan infections was investigated in Iranian cancer patients and a control group using microscopic and molecular methods.
This cross-sectional study was conducted on a group of 158 individuals with gastrointestinal and non-gastrointestinal cancers from hospitals affiliated with the Iran University of Medical Sciences, alongside 158 healthy individuals included in the control group. Stool samples were collected and examined using direct and concentration methods. The modified acid-fast staining method was used to detect coccidian parasite infections. DNA was extracted from the patients' samples, and PCR and sequencing were performed.
The overall prevalence of protozoan infections was higher in the cancer patients (31.6%) than in the control group (12.0%), with the difference between the two groups being statistically significant (P = 0.0001). The study identified Blastocystis hominis as the most common protozoan, with a prevalence of 22.8%, followed by Giardia lamblia, Entamoeba coli, Dientamoeba fragilis, and Chilomastix mesnili, with rates of 2.5%, 1.3%, 1.3%, and 0.6%, respectively, in the cancer patients. Cystoisospora belli and Cryptosporidium sp. were found as opportunistic infections in 2.5% and 0.6% of the cancer patients, respectively. Blastocystis hominis, with a prevalence of 9.5%, followed by Giardia lamblia at 1.3%, were the most common parasitic infections in the control group. A statistical difference was found for Cystoisospora belli (P = 0.044) and Blastocystis hominis (P = 0.0013) between the cancer patients and the control group. Cryptosporidium sp. was confirmed as Cryptosporidium parvum, and Cystoisospora belli was confirmed by PCR sequencing.
Chemotherapy, aside from corticosteroids, increases susceptibility to intestinal Protozoan infections in patients with hematological malignancies, particularly those with lymphoma and leukemia. The results indicated a higher risk of intestinal Protozoan infections, including opportunistic infections, in the cancer patients than in the control group. Cystoisospora belli and Cryptosporidium parvum were found to cause diarrhea in hematological malignancy patients undergoing chemotherapy.
寄生虫感染，尤其是机会性感染，是包括癌症患者在内的免疫功能低下患者的重要问题。本研究采用显微镜和分子方法调查了伊朗癌症患者和对照组人群中肠道原虫感染的流行情况。
本横断面研究纳入了来自伊朗医科大学附属医院的 158 例胃肠道和非胃肠道癌症患者（病例组），以及 158 例健康个体（对照组）。采集粪便样本，分别采用直接镜检和浓缩法进行检查。采用改良抗酸染色法检测球虫寄生虫感染。从患者样本中提取 DNA，进行 PCR 和测序。
癌症患者中原虫感染的总患病率（31.6%）高于对照组（12.0%），两组间差异具有统计学意义（P=0.0001）。研究发现，肠内原虫中最常见的是溶组织内阿米巴，感染率为 22.8%，其次是蓝氏贾第鞭毛虫、结肠内阿米巴、脆弱双核阿米巴和齿龈内阿米巴，分别为 2.5%、1.3%、1.3%和 0.6%。在癌症患者中，还发现 2.5%的机会性感染为隐孢子虫和 0.6%的感染为弓形体。在对照组中，溶组织内阿米巴感染率为 9.5%，其次是蓝氏贾第鞭毛虫感染率为 1.3%。癌症患者和对照组之间，在隐孢子虫（P=0.044）和溶组织内阿米巴（P=0.0013）方面存在统计学差异。通过 PCR 测序，证实隐孢子虫为微小隐孢子虫，弓形体为贝氏等孢球虫。
除了皮质类固醇外，化疗会增加血液恶性肿瘤患者（尤其是淋巴瘤和白血病患者）肠道原虫感染的易感性。结果表明，癌症患者肠道原虫感染，包括机会性感染的风险高于对照组。化疗可导致血液恶性肿瘤患者出现腹泻，其中隐孢子虫和微小隐孢子虫可引起腹泻。
