Molecular detection of microbial colonization in cervical mucus of women with and without endometriosis

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Reviewed Marked as Reviewed by Atrayees on 2023-8-9
PMID PubMed identifier for scientific articles.
DOI Digital object identifier for electronic documents.
Akiyama K, Nishioka K, Khan KN, Tanaka Y, Mori T, Nakaya T, Kitawaki J
American journal of reproductive immunology (New York, N.Y. : 1989)
cervical mucus, endometriosis, metagenomic analysis, microbiota
PROBLEM: Intrauterine microbial colonization and its association with the pathogenesis of endometriosis via an innate immune cascade have been reported. As a potential source of microbial transmission, information on microbial colonization in cervical mucus is unknown. We investigated pattern of microbiota in the cervical mucus collected from women with and without endometriosis using next-generation sequencing (NGS) technology. METHOD OF STUDY: Cervical mucus samples were collected from women with (n = 30) and without (n = 39) endometriosis. The communities of microbiota in cervical mucus in the endometriosis group and the control group were examined by Gram staining and NGS targeting the V5-V6 region of 16S ribosomal RNA gene. Copy number of some target bacteria was detected by real-time PCR. RESULTS: We confirmed visual presence of bacteria in cervical mucus by Gram staining. NGS analysis showed that distribution of microbiota was similar in cervical mucus of women with and without endometriosis regardless of the phases of the menstrual cycle. In addition to predominant Lactobacilli spp., the populations of Corynebacterium, Enterobacteriaceae, Flavobacterium, Pseudomonas, and Streptococcus were increased in the endometriosis group. Of them, Enterobacteriaceae and Streptococcus were identified as the more significant candidates in the endometriosis group than in controls by real-time PCR (P < 0.05 for each). CONCLUSION: Our NGS analysis of cervical mucus indicated that among a variable microbiota, two candidates (Enterobacteriaceae and Streptococcus) were more frequently detected in women with endometriosis. Further investigation is needed to elucidate a mechanistic link of these bacteria in the pathophysiology of endometriosis.

Experiment 1

Reviewed Marked as Reviewed by Atrayees on 2023-8-9

Curated date: 2021/08/07

Curator: Samara.Khan

Revision editor(s): Samara.Khan, WikiWorks, Peace Sandy


Location of subjects
Host species Species from which microbiome was sampled. Contact us to have more species added.
Homo sapiens
Body site Anatomical site where microbial samples were extracted from according to the Uber Anatomy Ontology
Uterine cervix Canalis cervicis uteri,Caudal segment of uterus,Cervical canal,Cervical canal of uterus,Cervix,Cervix of uterus,Cervix uteri,Neck of uterus,Uterine cervix,uterine cervix
Condition The experimental condition / phenotype studied according to the Experimental Factor Ontology
Endometriosis endometriosis,Endometriosis (clinical),endometriosis (disease),Endometriosis (disorder),Endometriosis (morphologic abnormality),ENDOMETRIOSIS NEC,Endometriosis NOS,Endometriosis NOS (disorder),Endometriosis of other specified sites,Endometriosis, site unspecified,Endometriosis
Group 0 name Corresponds to the control (unexposed) group for case-control studies
Women scheduled for laparoscopic surgery for benign uterine/ ovarian conditions
Group 1 name Corresponds to the case (exposed) group for case-control studies
Stage 3/4 endometriosis patients
Group 1 definition Diagnostic criteria applied to define the specific condition / phenotype represented in the case (exposed) group
Women were diagnosed with endometriosis via laparoscopic surgery and stages were categorized according to the revised American Society for Reproductive Medicine scoring system (r-ASRM).
Group 0 sample size Number of subjects in the control (unexposed) group
Group 1 sample size Number of subjects in the case (exposed) group
Antibiotics exclusion Number of days without antibiotics usage (if applicable) and other antibiotics-related criteria used to exclude participants (if any)
No antibiotics were taken 6 months prior to sample collection

Lab analysis

Sequencing type
16S variable region One or more hypervariable region(s) of the bacterial 16S gene
Sequencing platform Manufacturer and experimental platform used for quantifying microbial abundance
Ion Torrent

Statistical Analysis

Data transformation Data transformation applied to microbial abundance measurements prior to differential abundance testing (if any).
relative abundances
Statistical test
Mann-Whitney (Wilcoxon)
Significance threshold p-value or FDR threshold used for differential abundance testing (if any)
MHT correction Have statistical tests be corrected for multiple hypothesis testing (MHT)?

Alpha Diversity

Shannon Estimator of species richness and species evenness: more weight on species richness
Richness Number of species

Signature 1

Reviewed Marked as Reviewed by Atrayees on 2023-8-9

Curated date: 2021/08/08

Curator: Samara.Khan

Revision editor(s): Samara.Khan

Source: Figure 4

Description: Enterobactericeae and streptococcus were significantly higher in the cervical mucus of the endometriosis group than the control group.

Abundance in Group 1: increased abundance in Stage 3/4 endometriosis patients

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Revision editor(s): Samara.Khan