Introduction

The pathogenicity of Blastocystis spp. is still debated. Guidelines for donor feces screening differ in their advice to screen for Blastocystis spp., but when tested, its presence is a common reason for exclusion.¹Blastocystis spp. are correlated to increased bacterial alpha-diversity² and distinct bacterial groups³ and therefore its presence may indicate favorable efficacy of fecal microbiota transplantation (FMT). The latest European consensus report no longer advices to reject feces donors that test positive for Blastocystis spp.⁴ Only one paper has been published on human transmission of Blastocystis spp. via frozen FMT.⁵

Aims & Methods

We aimed to investigate the long-term effects of the application of Blastocystis-positive FMT, prepared with fresh feces.
In a FMT trial on FMT with refractory Irritable Bowel Syndrome (IBS) adolescents (age 16 – 20 years) received two administrations (at baseline and after 6 weeks) of fresh allogeneic FMT via nasoduodenal tube prepared with fecal samples from a Blastocystis spp. positive feces donor (NCT03074227). Blastocystis spp. presence and subtyping were determined using microscopy, PCR and Sanger sequencing.

Results

Three recipients received FMT from one donor colonized with Blastocystis subtype 3 (ST3). Two recipients were negative for Blastocystis spp. and one recipient carried ST2 at baseline prior to FMT. After FMT, the two prior-negative recipients tested positive for identical ST3 as the donor after FMT at 12 weeks, but lost carriership of this subtype at week 24 and week 48. The ST2 colonized recipient remained colonized with ST2 and did not acquire ST3 after FMT. Transient adverse events did occur, but did not differ from patients treated with Blastocystis spp.-negative FMT. No FMT-related serious adverse events occurred.

	Recipient	Baseline	Before FMT 1	Donor FMT 1	Before FMT 2	Donor FMT 2
		Week -2	Week 0	Week 0	Week 6	Week 6	Week 12	Week 24	Week 48
1	Woman, 18 y	negative	negative	ST3	ST 3	+, no seq	ST3	negative	negative
2	Woman, 20 y	negative	negative	ST3	+, no seq	ST3	ST 3	ST3	ST3
3	Woman, 16 y	ST2	ST2	ST3	+, no seq	ST3	ST2	ST2	ST2

Table 1: Sanger PCR sequencing results of frozen feces samples from three adolescents with IBS and one healthy donor. Samples were collected before, during and after the FMT treatment schedule with follow-up unto week 48. Light blue cells indicate a different sequence order of Blastocystis ST3 than the Blastocystis ST3 indicated in the dark blue cells. Grey cells indicate columns representing donor samples.
Abbreviations: FMT; fecal microbiota transplantation, ST; subtype, seq; sequence, y; years.

Conclusion

We present the first long-term results of Blastocystis spp. transmission by fresh FMT in three cases. Transient colonization with Blastocystis spp. did occur without the occurrence of FMT-related serious adverse events.

References

1. Benard MV, de Bruijn CMA, Fenneman AC, Wortelboer K, Zeevenhoven J, Rethans B, et al. Challenges and costs of donor screening for fecal microbiota transplantations. PLoS One. 2022;17(10):e0276323.
2. Tito RY, Chaffron S, Caenepeel C, Lima-Mendez G, Wang J, Vieira-Silva S, et al. Population-level analysis of Blastocystis subtype prevalence and variation in the human gut microbiota. Gut. 2019;68(7):1180-9.
3. Nieves-Ramirez ME, Partida-Rodriguez O, Laforest-Lapointe I, Reynolds LA, Brown EM, Valdez-Salazar A, et al. Asymptomatic Intestinal Colonization with Protist Blastocystis Is Strongly Associated with Distinct Microbiome Ecological Patterns. mSystems. 2018;3(3).
4. Keller JJ, Ooijevaar RE, Hvas CL, Terveer EM, Lieberknecht SC, Hogenauer C, et al. A standardised model for stool banking for faecal microbiota transplantation: a consensus report from a multidisciplinary UEG working group. United European Gastroenterol J. 2021;9(2):229-47.
5. Terveer EM, van Gool T, Ooijevaar RE, Sanders I, Boeije-Koppenol E, Keller JJ, et al. Human Transmission of Blastocystis by Fecal Microbiota Transplantation Without Development of Gastrointestinal Symptoms in Recipients. Clin Infect Dis. 2020;71(10):2630-6.

Disclosure

CYP has received research grants from Gilead and Perspectum, consultancy fee from Chemomab and NGM, and speaker’s fee from Tillotts. The other authors disclose no conflicts.

Introduction

There is an ongoing paradigm shift toward serology-based diagnosis of celiac disease (CeD). It is essential to target potential endoscopies for those most likely to benefit. Anemia is a common symptom of CeD that may warrant further investigations, but the prevalence and clinical relevance of endoscopic findings in anemic CeD patients remain unclear.

Aims & Methods

The aim of this study was to compare the prevalence of upper and lower endoscopic findings between anemic patients and non-CeD controls, and to identify predictors of significant findings in CeD patients. Medical data, including upper and lower endoscopy findings, were collected from 162 CeD patients and 350 controls. Binary logistic regression analysis was used to identify predictors of findings.

Results

CeD patients were younger (median 49 vs 66 years, p<0.001) and had fewer risk factors such as smoking (14% vs 25%, p<0.001), alcohol abuse (4% vs 14%, p<0.001), chronic comorbidities (55% vs 83%, p<0.001), and previous malignancies (1% vs 8%, p=0.002).
In comparison of upper endoscopy findings, CeD patients had fewer significant findings (21% vs 53%, p<0.001), H. Pylori positive gastritis (6% vs 19%, p<0.001), gastric ulcers (0% vs 5%, p=0.006), and atrophic gastritis (3% vs 9%, p=0.005) compared to the controls.
Twenty-four patients and 208 controls had undergone lower endoscopy with celiac patients more frequently demonstrating significant findings (54% vs 28%, p=0.008), non-specific inflammation (21% vs 1%, p<0.001) and colorectal cancer (25% vs 9%, p=0.018).
Predictors of significant upper endoscopy findings in CeD patients were older age (OR 1.03, 95% CI 1.01-1.05), age >50 (2.44, 1.18-5.06), co-existing chronic conditions (3.45, 1.53-7.78), gastrointestinal symptoms (2.31, 1.07-4.98), and use of acetylsalicylic acid (2.38, 1.01-5.06), and of colonoscopy findings older age (1.01, 0.99-1.04), co-existing conditions (3.48, 1.12-10.8), and gastrointestinal symptoms (4.73, 1.34-16.7).

Conclusion

CeD patients had fewer findings on upper endoscopy but, despite being younger and having fewer risk factors, showed more findings on lower endoscopy compared to controls. In older CeD patients presenting with anemia, lower endoscopy should be strongly considered.