Blastocystis colonization uncommon in Chinese type 2 diabetes patients, study finds

Blastocystis, a ubiquitous enteric protist whose clinical relevance remains debated, is relatively uncommon in both people with type 2 diabetes mellitus and non-diabetic individuals in a coastal region of eastern China, according to a new case-control study conducted in Zhejiang. The research found no statistically significant difference in colonization rates between the two groups, despite a slightly higher raw prevalence among the diabetes patients.

The study recruited 359 patients with type 2 diabetes and 188 age- and sex-matched non-diabetic controls on a consecutive basis. Researchers detected Blastocystis colonization using PCR targeting the small subunit ribosomal RNA gene, and determined subtypes through Sanger sequencing and phylogenetic analysis. Between-group comparisons relied on Pearson’s chi-square test or Fisher’s exact test.

The overall prevalence of colonization was 4.74 percent (17 of 359) in the type 2 diabetes group and 3.19 percent (6 of 188) in the control group, a difference the authors report as not statistically significant (P = 0.438). These figures indicate that in this setting, diabetes status alone was not associated with a markedly higher likelihood of carrying the protist.

Geography did appear to matter. Across the study population, rural residents had a significantly higher colonization rate than urban residents. The pattern was consistent in both groups: among diabetes patients, colonization was 6.20 percent in rural residents versus 0.99 percent in urban residents (P = 0.037), and among controls it was 4.51 percent versus 0.00 percent (P = 0.174), although the latter comparison did not reach statistical significance.

Within the diabetes group, disease duration emerged as a specific factor associated with colonization. Patients who had lived with type 2 diabetes for ten years or longer showed a colonization prevalence roughly four times higher than those with a shorter duration, at 6.47 percent versus 1.57 percent (P = 0.037). The authors suggest this finding supports targeted surveillance and health education for diabetic patients with long disease duration and rural residence.

Subtype analysis of the 23 positive isolates revealed a narrow distribution. ST3 was the predominant subtype, accounting for 69.57 percent of isolates, followed by ST1 at 30.43 percent. All isolates from the control group were ST3, while ST1 was detected exclusively in the type 2 diabetes group.

Genetic characterization added a further layer of detail. ST1 showed higher genetic diversity than ST3, with three alleles identified compared with two for ST3. The authors note that epidemiological data on Blastocystis colonization in patients with type 2 diabetes remain scarce in eastern China, which motivated the study’s aim to characterize prevalence, subtype distribution, genetic features and associated factors in this population.

The study’s conclusions are deliberately measured. Blastocystis colonization is described as relatively uncommon in both the diabetic and non-diabetic populations of this coastal Chinese region, with no significant intergroup prevalence difference. Rural residence is identified as a shared factor associated with colonization, while longer diabetes duration is a factor specific to the type 2 diabetes group. As a case-control study with a modest number of positive isolates, the findings describe associations within this regional population rather than establishing causal effects, and the authors frame them as supporting targeted surveillance rather than clinical action.

Subject of Research: Blastocystis colonization prevalence and subtypes in type 2 diabetes patients and non-diabetic controls in Zhejiang, China

Article Title: Prevalence, subtype distribution, genetic characteristics and associated factors of Blastocystis colonization in type 2 diabetes mellitus patients and non-diabetic controls in Zhejiang, China

Article References: Wu, S., Guan, Y., Zhu, F., Wen, H., Zhu, J., Yan, C., Zhao, W., Zhu, H., & Ke, J. (2026). Prevalence, subtype distribution, genetic characteristics and associated factors of Blastocystis colonization in type 2 diabetes mellitus patients and non-diabetic controls in Zhejiang, China. BMC Microbiology. https://doi.org/10.1186/s12866-026-05846-3

Image Credits: AI Generated

DOI: 10.1186/s12866-026-05846-3

Keywords: Blastocystis, type 2 diabetes, colonization, ST3, ST1, Zhejiang, case-control study, PCR, rural residence, gut protist, epidemiology, China