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Risvanli A, Tanyeri B, Yildirim G, Tatar Y, Gedikpinar M, Kalender H, Safak T, Yuksel B, Karagulle B, Yilmaz O, Kilinc MA. Metrisor: A novel diagnostic method for metritis detection in cattle based on machine learning and sensors. Theriogenology 2024; 223:115-121. [PMID: 38714077 DOI: 10.1016/j.theriogenology.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/25/2024] [Accepted: 05/02/2024] [Indexed: 05/09/2024]
Abstract
The Metrisor device has been developed using gas sensors for rapid, highly accurate and effective diagnosis of metritis. 513 cattle uteri were collected from abattoirs and swabs were taken for microbiological testing. The Metrisor device was used to measure intrauterine gases. The results showed a bacterial growth rate of 75.75 % in uteri with clinical metritis. In uteri positive for clinical metritis, the most commonly isolated and identified bacteria were Trueperella pyogenes, Fusobacterium necrophorum and Escherichia coli. Measurements taken with Metrisor to determine the presence of metritis in the uterus yielded the most successful results in evaluations of relevant machine learning algorithms. The ICO (Iterative Classifier Optimizer) algorithm achieved 71.22 % accuracy, 64.40 % precision and 71.20 % recall. Experiments were conducted to examine bacterial growth in the uterus and the random forest algorithm produced the most successful results with accuracy, precision and recall values of 78.16 %, 75.30 % and 78.20 % respectively. ICO also showed high performance in experiments to determine bacterial growth in metritis-positive uteri, with accuracy, precision and recall values of 78.97 %, 77.20 % and 79.00 %, respectively. In conclusion, the Metrisor device demonstrated high accuracy in detecting metritis and bacterial growth in uteri and could identify bacteria such as E. coli, S. aureus, coagulase-negative staphylococci, T. pyogenes, Bacillus spp., Clostridium spp. and F. necrophorum with rates up to 80 %. It provides a reliable, rapid and effective means of detecting metritis in animals in the field without the need for laboratory facilities.
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Ying X, Xu G, Wang H, Wang Y. An altered uterine microbiota with endometrial hyperplasia. BMC Microbiol 2024; 24:258. [PMID: 38997629 PMCID: PMC11242002 DOI: 10.1186/s12866-024-03379-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 06/17/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND Endometrial hyperplasia (EH) is a precursor to endometrial cancer, and the role of the microbiome in its development is unclear. RESULTS The present study investigated the uterine microbiome in patients with benign uterine conditions and endometrial hyperplasia. A significant structural shift in the uterine microbiome of patients with endometrial hyperplasia compared to those with benign conditions was found. Delftia, Serratia and Stenotrophomonas were significantly enriched in endometrial hyperplasia samples and associated with the presence of endometrial hyperplasia. CONCLUSIONS The novel finding suggested that increased abundance of Delftia, Serratia and Stenotrophomonas is associated with the presence of endometrial hyperplasia. Further investigation is needed to determine the value of these microbes as biomarkers for endometrial hyperplasia.
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Yang B, Wang Y, Yan X, Fen Q, Chi Y. Primer Exchange Reaction (PER)-Based Construction of Scaffold for Low-Speed Centrifugation-Based Isolation and Quantitative Analysis of P. aeruginosa and its application in analyzing uterine secretions with intrauterine adhesion. Appl Biochem Biotechnol 2024; 196:4038-4048. [PMID: 37819459 DOI: 10.1007/s12010-023-04742-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2023] [Indexed: 10/13/2023]
Abstract
Efficient isolation and sensitive quantification of Pseudomonas aeruginosa (P. aeruginosa) are crucial for identifying intrauterine infections and preventing the occurrence of intrauterine adhesion (IUA). However, traditional approaches, such as culture-based approach, are time-consuming. Herein, we constructed a detection scaffold by using primer exchange reaction (PER) that integrated the low-speed centrifugation-based isolation and sensitive quantification of target pathogenic bacteria. The established approach possesses several advantages, including (i) the approach is capable of simultaneous isolation and sensitive quantification of target bacteria; (ii) low-speed centrifugation or even manual equipment could be used to isolate target bacteria; and (iii) a low limit of detection was obtained as 54 cfu/mL. Based on this, the approach is a promising approach in analyzing P. aeruginosa from uterine secretions with IUA.
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Bai S, Xu G, Mo H, Qi T, Fu S, Zhu L, Huang B, Zhang J, Chen H. Investigating into microbiota in the uterine cavity of the unexplained recurrent pregnancy loss patients in early pregnancy. Placenta 2024; 152:1-8. [PMID: 38729066 DOI: 10.1016/j.placenta.2024.05.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/25/2024] [Accepted: 05/06/2024] [Indexed: 05/12/2024]
Abstract
INTRODUCTION The majority of unexplained recurrent pregnancy loss (URPL) cases have been attributed to immune abnormalities. Inappropriate changes in microbiota could lead to immune disorders. However, the specific role of uterine cavity microbiota in URPL remains unclear, and only a limited number of related studies are available for reference. METHODS We utilized double-lumen embryo transfer tubes to collect uterine cavity fluid samples from pregnant women in their first trimester. Subsequently, we conducted 16S rRNA sequencing to analyze the composition and abundance of the microbiota in these samples. RESULTS For this study, we enlisted 10 cases of URPL and 28 cases of induced miscarriages during early pregnancy. Microbial communities were detected in all samples of the URPL group (100 %, n = 10), whereas none were found in the control group (0 %, n = 28). Among the identified microbes, Lactobacillus and Curvibacter were the two most dominant species. The abundance of Curvibacter is correlated with the number of NK cells in peripheral blood (r = -0.759, P = 0.018). DISCUSSION This study revealed that during early pregnancy, Lactobacillus and Curvibacter were the predominant colonizers in the uterine cavity of URPL patients and were associated with URPL. Consequently, alterations in the dominant microbiota may lead to adverse pregnancy outcomes.
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Ozcan G, Tanyolaç Talay ZG, Paerhati E, Eren OC, Coskun N, Sahin D, Alnajjar I, Albayrak O, Gursoy A, Keskin O, Celik E, Can F. Dysbiosis in pregnant mice induced by transfer of human vaginal microbiota followed by reversal of pathological changes in the uterus and placenta via progesterone treatment. BMC Pregnancy Childbirth 2024; 24:427. [PMID: 38877443 PMCID: PMC11177491 DOI: 10.1186/s12884-024-06595-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 05/20/2024] [Indexed: 06/16/2024] Open
Abstract
OBJECTIVE The vaginal microbiota dysbiosis induces inflammation in the uterus that triggers tissue damage and is associated with preterm birth. Progesterone is used to prevent labor in pregnant women at risk of preterm birth. However, the mechanism of action of progesterone still needs to be clarified. We aimed to show the immunomodulatory effect of progesterone on the inflammation of uterine tissue triggered by dysbiotic vaginal microbiota in a pregnant mouse model. METHODS Healthy (n = 6) and dysbiotic (n = 7) vaginal microbiota samples isolated from pregnant women were transferred to control (n = 10) and dysbiotic (n = 14) pregnant mouse groups. The dysbiotic microbiota transferred group was treated with 1 mg progesterone (n = 7). Flow cytometry and immunohistochemistry analyses were used to evaluate inflammatory processes. Vaginal microbiota samples were analyzed by 16 S rRNA sequencing. RESULTS Vaginal exposure to dysbiotic microbiota resulted in macrophage accumulation in the uterus and cellular damage in the placenta. Even though TNF and IL-6 elevations were not significant after dysbiotic microbiota transplantation, progesterone treatment decreased TNF and IL-6 expressions from 49.085 to 31.274% (p = 0.0313) and 29.279-21.216% (p = 0.0167), respectively. Besides, the macrophage density in the uterus was reduced, and less cellular damage in the placenta was observed. CONCLUSION Analyzing the vaginal microbiota before or during pregnancy may support the decision for initiation of progesterone therapy. Our results also guide the development of new strategies for preventing preterm birth.
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Garzon A, Basbas C, Schlesener C, Silva-del-Rio N, Karle BM, Lima FS, Weimer BC, Pereira RV. WGS of intrauterine E. coli from cows with early postpartum uterine infection reveals a non-uterine specific genotype and virulence factors. mBio 2024; 15:e0102724. [PMID: 38742889 PMCID: PMC11237492 DOI: 10.1128/mbio.01027-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 05/16/2024] Open
Abstract
Escherichia coli has been attributed to playing a major role in a cascade of events that affect the prevalence and severity of uterine disease in cattle. The objectives of this project were to (i) define the association between the prevalence of specific antimicrobial resistance and virulence factor genes in E. coli with the clinical status related to uterine infection, (ii) identify the genetic relationship between E. coli isolates from cows with diarrhea, with mastitis, and with and without metritis, and (iii) determine the association between the phenotypic and genotypic antimicrobial resistance identified on the E. coli isolated from postpartum cattle. Bacterial isolates (n = 148) were obtained from a larger cross-sectional study. Cows were categorized into one of three clinical groups before enrollment: metritis, cows with purulent discharge, and control cows. For genomic comparison, public genomes (n = 130) from cows with diarrhea, mastitis, and metritis were included in a genome-wide association study, to evaluate differences between the drug classes or the virulence factor category among clinical groups. A distinct E. coli genotype associated with metritis could not be identified. Instead, a high genetic diversity among the isolates from uterine sources was present. A virulence factor previously associated with metritis (fimH) using PCR was not associated with metritis. There was moderate accuracy for whole-genome sequencing to predict phenotypic resistance, which varied depending on the antimicrobial tested. Findings from this study contradict the traditional pathotype classification and the unique intrauterine E. coli genotype associated with metritis in dairy cows.IMPORTANCEMetritis is a common infectious disease in dairy cattle and the second most common reason for treating a cow with antimicrobials. The pathophysiology of the disease is complex and is not completely understood. Specific endometrial pathogenic Escherichia coli have been reported to be adapted to the endometrium and sometimes lead to uterine disease. Unfortunately, the specific genomic details of the endometrial-adapted isolates have not been investigated using enough genomes to represent the genomic diversity of this organism to identify specific virulence genes that are consistently associated with disease development and severity. Results from this study provide key microbial ecological advances by elucidating and challenging accepted concepts for the role of Intrauterine E. coli in metritis in dairy cattle, especially contradicting the existence of a unique intrauterine E. coli genotype associated with metritis in dairy cows, which was not found in our study.
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Shaukat A, Hanif S, Shaukat I, Rajput SA, Shukat R, Huang SC, H Almutairi M, Shaukat S, Ali M, Hassan M, Kiani FA, Su RW. Up-regulation of inflammatory, oxidative stress, and apoptotic mediators via inflammatory, oxidative stress, and apoptosis-associated pathways in bovine endometritis. Microb Pathog 2024; 191:106660. [PMID: 38657710 DOI: 10.1016/j.micpath.2024.106660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 04/13/2024] [Accepted: 04/19/2024] [Indexed: 04/26/2024]
Abstract
Endometritis is the inflammation of the endothelial lining of the uterine lumen and is multifactorial in etiology. Escherichia (E.) coli is a Gram-negative bacteria, generally considered as a primary causative agent for bovine endometritis. Bovine endometritis is characterized by the activation of Toll-like receptors (TLRs) by E. coli, which in turn triggers inflammation, oxidative stress, and apoptosis. The objective of this study was to investigate the gene expression of inflammatory, oxidative stress, and apoptotic markers related to endometritis in the uteri of cows. Twenty uterine tissues were collected from the abattoir. Histologically, congestion, edema, hyperemia, and hemorrhagic lesions with massive infiltration of neutrophil and cell necrosis were detected markedly (P < 0.05) in infected uterine samples. Additionally, we identify E. coli using the ybbW gene (177 base pairs; E. coli-specific gene) from infected uterine samples. Moreover, qPCR and western blot results indicated that TLR2, TLR4, proinflammatory mediators, and apoptosis-mediated genes upregulated except Bcl-2, which is antiapoptotic, and there were downregulations of oxidative stress-related genes in the infected uterine tissue. The results of our study suggested that different gene expression regimes related to the immune system reflex were activated in infected uteri. This research gives a novel understanding of active immunological response in bovine endometritis.
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Retamar GC, Bustos CP, Guillemi EC, Becú T, Ivanissevich A, Mesplet M, Muñoz AJ. Streptococcus equi subsp. zooepidemicus: High molecular diversity of Argentinian strains isolated from mares with endometritis. Res Vet Sci 2024; 173:105242. [PMID: 38640833 DOI: 10.1016/j.rvsc.2024.105242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/27/2024] [Accepted: 03/24/2024] [Indexed: 04/21/2024]
Abstract
Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is a mucosal commensal of the lower genital tract in horses and is the most isolated bacterium causing endometritis in mares. The aim of this study was to determine the molecular diversity of S. zooepidemicus obtained from endometritis in mares in Buenos Aires province, Argentina. Thirty isolates obtained from the uterus of mares in 2005 and 2017 were studied. The MLST scheme was applied to identify the Argentinian genotypes and the clonal relationships and patterns of evolutionary descent were identified using the eBURST algorithm - goeBURST. Twenty six different Sequence types (STs) were identified, being only 11 of them previously reported in horses and also, from several host species and tissues. The other 15 STs were reported in Argentinian reproductive strains of mares in our study for the first time. The genotypes obtained from uterus in Argentina were not evenly distributed when all the published S. zooepidemicus STs were analysed, thus, it was not possible to establish that the same lineage circulates in our equine population. The fact that the identified genotypes were also reported in other countries, diverse samples and host species suggest that there is not a host, and an anatomical niche adaptation. Finally, the isolation of the same genotype in the vagina/clitoris and the uterus of the same mare highlights the versatility of S. zooepidemicus and its role as an opportunistic pathogen.
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Figueiredo CC, Monteiro HF, Cunha F, Bisinotto DZ, Ruiz AR, Duarte GA, Ge Y, Lima FS, Mohamadzadeh M, Galvão KN, Bisinotto RS. Shifts in uterine microbiome associated with pregnancy outcomes at first insemination and clinical cure in dairy cows with metritis. Sci Rep 2024; 14:11864. [PMID: 38789554 PMCID: PMC11126406 DOI: 10.1038/s41598-024-61704-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Objectives were to assess differences in uterine microbiome associated with clinical cure and pregnancy outcomes in dairy cows treated for metritis. Cows with metritis (reddish-brownish, watery, and fetid vaginal discharge) were paired with cows without metritis based on parity and days postpartum. Uterine contents were collected through transcervical lavage at diagnosis, five days later following antimicrobial therapy (day 5), and at 40 days postpartum. Uterine microbiome was assessed by sequencing the V4 hypervariable region of the 16S rRNA gene. Although alpha-diversity based on Chao1, Shannon, and inverse Simpson indexes at diagnosis did not differ between cows with and without metritis, disease was associated with differences in beta-diversity. Prevalence of Porphyromonas, Bacteroides, and Veillonella was greater in cows with metritis. Streptococcus, Sphingomonas, and Ureaplasma were more prevalent in cows without metritis. Differences in beta-diversity between cows with and without metritis persisted on day 5. Uterine microbiome was not associated with clinical cure. Richness and alpha-diversity, but not beta-diversity, of uterine microbiome 40 days postpartum were associated with metritis and pregnancy. No relationship between uterine microbiome and pregnancy outcomes was observed. Results indicate that factors other than changes in intrauterine bacterial community underlie fertility loss and clinical cure in cows with metritis.
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Yazlık MO, Müştak İB, Özkan H, Vural SA, Kaya U, Özöner Ö, Mutluer İ, Altınbaş YF, Soylu MS, Vural MR. The presence of virulence factor genes downregulates uterine AQP3 and alters glutathione peroxidase activity and uterine histopathology in canine pyometra. Reprod Domest Anim 2024; 59:e14615. [PMID: 38798181 DOI: 10.1111/rda.14615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/30/2024] [Accepted: 05/09/2024] [Indexed: 05/29/2024]
Abstract
Present study was designed to evaluate the role of virulence factor genes (papG, cnf1 and hylA) in the pathogenesis of canine pyometra. Antimicrobial susceptibility test and detection of virulence genes were performed Escherichia coli (E. coli) detected in uterine swab samples. Animals were divided into two groups based on the presence (VF+, n:14) or absence (VF-, n:7) of the virulence factor genes papG, cnf1 and hylA. Blood and tissue glutathione peroxidase activity, uterine histopathologic analysis and AQP3, ESR1, PGR, OXTR gene expressions were determined in both groups. Statistical analyses were performed using Stata version 15.1. All E. coli isolates were susceptible to amikacin, whereas resistant to ampicillin, amoxicillin/clavulanic acid and lincomycin. None of the isolates were susceptible to cefotaxime. E. coli isolates had at least one virulence gene. The most prevalent gene was fimH (100%), followed by fyuA (95.8%), usp (83.3%), sfa (75%), cnf1 and hlyA (70.8%) genes. Blood GPx activity was greater in VF+ animals. On the other hand, uterine tissue GPx activity was lower in VF+ group compared to the control group. Expression levels of AQP3 were upregulated more than fivefold in VF-dogs compared to the control group. In addition, AQP3 expression levels were found approximately threefold higher in VF (-) than VF (+) group (p < .05). Varying degree of inflammation noted for all animals with pyometra, but the presence of bacteria noted only in VF+ animals. In conclusion, the presence of virulence factor genes does not play a role in the histopathological degree of inflammation, the presence of bacteria was found to vary. Serum GPx activity increased in VF+ animals. While the hormone receptor expressions were similar, AQP expression was upregulated in the absence of virulence factor genes.
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Cai XS, Jiang H, Xiao J, Yan X, Xie P, Yu W, Lv WF, Wang J, Meng X, Chen CZ, Zhang M, Zhang Y, Yuan B, Zhang JB. Changes in bacterial community composition in the uterus of Holstein cow with endometritis before and after treatment with oxytetracycline. Sci Rep 2024; 14:9511. [PMID: 38664449 PMCID: PMC11045718 DOI: 10.1038/s41598-024-59674-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 04/13/2024] [Indexed: 04/28/2024] Open
Abstract
It is important to study the bacteria that cause endometritis to identify effective therapeutic drugs for dairy cows. In this study, 20% oxytetracycline was used to treat Holstein cows (n = 6) with severe endometritis. Additional 10 Holstein cows (5 for healthy cows, 5 for cows with mild endometritis) were also selected. At the same time, changes in bacterial communities were monitored by high-throughput sequencing. The results show that Escherichia coli, Staphylococcus aureus and other common pathogenic bacteria could be detected by traditional methods in cows both with and without endometritis. However, 16S sequencing results show that changes in the abundance of these bacteria were not significant. Endometritis is often caused by mixed infections in the uterus. Oxytetracycline did not completely remove existing bacteria. However, oxytetracycline could effectively inhibit endometritis and had a significant inhibitory effect on the genera Bacteroides, Trueperella, Peptoniphilus, Parvimonas, Porphyromonas, and Fusobacterium but had no significant inhibitory effect on the bacterial genera Marinospirillum, Erysipelothrix, and Enteractinococcus. During oxytetracycline treatment, the cell motility, endocrine system, exogenous system, glycan biosynthesis and metabolism, lipid metabolism, metabolism of terpenoids, polyketides, cofactors and vitamins, signal transduction, and transport and catabolism pathways were affected.
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Gobikrushanth M, Dos Santos SJ, Champika F, Hill JE, Dadarwal D. Uterine microbial profiles in healthy postpartum dairy cows do not vary with sampling techniques or phases of estrous cycle. Theriogenology 2024; 214:298-306. [PMID: 37976796 DOI: 10.1016/j.theriogenology.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/30/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023]
Abstract
In this study, we aimed to compare uterine microbial profiles in postpartum dairy cows, determined by bacteriological culture and next-generation sequencing, using three uterine sampling techniques (swab, cytobrush, and lavage) and induced phases of the estrous cycle (estrus and diestrus). Fifteen healthy postpartum dairy cows at 53 ± 5 days postpartum were enrolled in the study. Uterine samples were collected during a fixed-time artificial insemination protocol. Viable bacteria were aerobically cultured from part of each sample, and bacterial isolates were identified through Sanger sequencing of the 16S rRNA gene. Total genomic DNA was extracted from the remainder of undiluted samples to quantify bacterial load using 16S rRNA qPCR and characterize the microbiome by metagenomic sequencing of the V1-V3 region of the 16S rRNA gene. Microbial profiles and composition were analyzed using the Shannon-Weaver diversity index and principal component analysis, respectively. Out of 87 samples, 88 % (77/87) were culture positive. The proportion of culture-positive uterine samples did not differ between sampling techniques (P = 0.39) or estrous cycle phases (P = 0.99). However, swab, cytobrush, and lavage techniques yielded 1.5, 9 and 9 times greater bacterial loads (P < 0.01), respectively, during diestrus than estrus phase. Moreover, during diestrus phase, the cytobrush method yielded 3 and 6 times more bacteria (P < 0.01) than both the lavage and swab methods. The most abundant bacterial genera identified from both bacteriological culture and metagenomic sequencing were Bacillus and Enterococcus, regardless of sampling technique or phases of the estrous cycle. Bacterial genera in moderate to low abundance through metagenomic sequencing included Streptococcus, Oscillospiraceae, and Lachnospiraceae. Notably, the uterine microbial profiles and composition, determined by metagenomic sequencing, did not differ by sampling techniques (P = 0.55 and P = 0.60, respectively) or estrous cycle phases (P = 0.34 and P = 0.17, respectively). In conclusion, our results suggest that any of the sampling techniques can be reliably used to study the uterine microbiome of healthy cows at random phases of the estrous cycle. However, it is important to consider potential differences in bacterial yield as a confounding factor.
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Mekibib B, Belachew M, Asrade B, Badada G, Abebe R. Incidence of uterine infections, major bacteria and antimicrobial resistance in postpartum dairy cows in southern Ethiopia. BMC Microbiol 2024; 24:4. [PMID: 38172685 PMCID: PMC10763139 DOI: 10.1186/s12866-023-03160-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Uterine infections, primarily caused by bacterial pathogens, pose a significant problem for dairy farmers worldwide, leading to poor reproductive performance and economic losses. However, the bacteria responsible for uterine infections have not been adequately studied, nor has the antibiotic susceptibility of the causative bacteria been frequently tested in Ethiopia. This study aims to estimate the cumulative incidence of uterine infections in postpartum dairy cows, identify bacterial causes and determine antimicrobial susceptibility profile of the isolated bacteria. METHODS A prospective cohort study was conducted in which 236 cows from 74 dairy farms were monitored biweekly from calving to 90 days postpartum for metritis, endometritis and other disorders. Aseptic uterine swab samples were collected from 40 cows with uterine infections. The samples were cultured, and the isolated bacteria were tested for antimicrobial susceptibility using the disk diffusion method. RESULTS Out of 236 cows monitored during the postpartum phase, 45 (19.1%) were found to have contracted uterine infection. The cumulative incidence of metritis was 11.4% (n = 27), while the cumulative incidence of endometritis was 7.6% (n = 18). Of the 40 cultured swab samples, 29 (72.5%) had one or more bacteria isolated. The most commonly isolated bacteria were Escherichia coli (45%), coagulase-positive staphylococci (30%), and Klebsiella spp. (22.5%). Other bacterial spp, including Arcanobacterium pyogenes (12.5%), Fusobacterium spp. (12.5%), Enterobacter aerogenes (12.5%), coagulase-negative staphylococci (12.5%), Streptococcus spp. (7.5%), Salmonella spp, (5%) Proteus spp (5%) and Pasteurella spp (2.5%) were also isolated. All of the isolated bacteria demonstrated resistance to at least one of the antimicrobials tested. Multidrug resistance was observed in E. coli, Klebsiella spp., A. pyogenes, and Fusobacterium spp. Gentamicin was found to be the most effective antimicrobial against all bacteria tested, while tetracycline was the least effective of all. CONCLUSION The study found that a significant proportion of cows in the population were affected by uterine infections and the isolated bacteria developed resistance to several antimicrobials. The study emphasizes the need for responsible use of antimicrobials to prevent the emergence of antimicrobial resistance. It also highlights the importance of raising awareness among dairy farmers to avoid the indiscriminate use of antibiotics and its consequences.
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Çömlekcioğlu U, Jezierska S, Opsomer G, Pascottini OB. Uterine microbial ecology and disease in cattle: A review. Theriogenology 2024; 213:66-78. [PMID: 37804686 DOI: 10.1016/j.theriogenology.2023.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 10/09/2023]
Abstract
Due to the critical contribution of the uterine-associated microbiota in reproductive health, physiology, and performance, culture-independent methods have been increasingly employed to unravel key aspects of microbial ecology in the uterus of cattle. Nowadays, we know that bacterial diversity is crucial to maintain uterine health, however, there is still no consensus on the exact composition of a healthy uterine microbiota (or eubiosis). Generally, loss of bacterial diversity (or dysbiosis) contributes to the development of uterine infections, associated with increased relative abundances of Bacteroides, Fusobacterium, Trueperella, and Porphyromonas. Uterine infections are highly prevalent and gravely influence the profitability of cattle operations, animal welfare, and public health. Thus, understanding the dynamics of uterine microbial ecology is essential to develop effective strategies focused on preventing and mitigating the adverse effects of uterine dysbiosis as well as assisting in the process of restoring the core, healthy uterine microbiota. The aim of this review is to summarize research conducted in the microbial ecology of bovine uteri. We discuss the origin of the uterine microflora of healthy cows and the factors influencing its composition. In addition, we review the biology of specific pathogens that are known to increase in abundance during the occurrence of uterine disease. Lastly, we provide an overview of the bacterial biofilm in the bovine endometrium, and we briefly summarize the rationale for the use of probiotics to prevent uterine disease in cattle.
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Banchi P, Colitti B, Opsomer G, Rota A, Van Soom A. The dogma of the sterile uterus revisited: does microbial seeding occur during fetal life in humans and animals? Reproduction 2024; 167:e230078. [PMID: 37903182 PMCID: PMC10762539 DOI: 10.1530/rep-23-0078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 10/30/2023] [Indexed: 11/01/2023]
Abstract
In brief Opposing conclusions have been drawn regarding the presence of viable bacteria in the healthy pregnant uterus. Current evidence in humans and animals suggests that fetomaternal tissues present only traces of bacteria whose viability is still to be proven. Abstract The debate about the pioneer colonization of the fetus is still open, being the 'in utero colonization' hypothesis versus the 'sterile womb paradigm' the two opposing sides. The seed in this field of research sprouted in human medicine in the last decade and became a central topic in other mammals as well. We aimed to review the literature on bacterial colonization of the healthy placenta, amniotic fluid, and meconium as representatives of the fetal environment. What emerges is that confirming the colonization of fetomaternal tissues by viable bacteria is challenging in humans as well as in animals. Contamination represents the major risk in this type of research as it can be related to different parts of the study design. Sampling at natural parturition or postpartum introduces risk for colonization by the vaginal microbiome of the mother or from the environment. Culture does not reveal the presence of unculturable microorganisms, and sequencing does not allow confirming bacterial viability, while also introducing the variability associated with the data analysis. Therefore, on the basis of the present review, we provide some guidelines on the best practices when performing this type of studies. What emerges from the current literature in humans and animals is that fetomaternal tissues are characterized by a very low biomass, that the viability of bacteria eventually present is still to be confirmed, while massive colonization happens at birth, priming the individual, regardless of the species.
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Malaluang P, Åkerholm T, Nyman G, Lindahl J, Hansson I, Morrell JM. Bacteria in the healthy equine vagina during the estrous cycle. Theriogenology 2024; 213:11-18. [PMID: 37793220 DOI: 10.1016/j.theriogenology.2023.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 10/06/2023]
Abstract
An understanding of the normal bacterial microbiota of any organ is essential to provide the background to conditions and interventions that might cause the microbiota to change. In the vagina of the mare, a change of bacterial microbiota could be induced by introduction of semen, treatment with antibiotics, discharge from an unhealthy uterus etc. Previous studies on equine vaginal bacteria are not all conducted in the same way and results are not altogether consistent. Therefore, this study was designed to provide a deeper understanding of the bacterial microbiota of the mare vagina, and possible changes throughout the estrous cycle. The cranial portion of the vagina was sampled on day 0 (ovulation), day 3, day 7, and day 14 of the estrous cycle. The vaginal sampling was conducted with double-guarded occluded swabs from the cranial floor of the vagina. Ovulation was determined by rectal palpation and ultrasonic examination, and the day 0 samples were taken within ±24 h of ovulation. Swabs were brought to the laboratory in Amies medium within 2-3 h and were plated out immediately on both selective and non-selective agars. Results were registered as amount of growth (qualitatively), bacterial species and number of isolates. Bacterial growth was highest on day 3 and 7, representing the beginning and middle of diestrus. The dominant bacteria were Escherichia coli and Streptococcus zooepidemicus. Escherichia coli was especially dominant in maiden mares, compared to the mares that had foaled. An increase in bacterial diversity throughout the estrous cycle was observed, being highest on day 14. These results suggest that there are changes in the bacterial microbiota of the mare vagina throughout the normal estrous cycle.
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Murga Valderrama NL, Segura Portocarrero GT, Romani Vasquez AC, Frias Torres H, Flores Durand GJ, Cornejo Villanueva VG, Del Solar JC, Costa Polveiro R, da Silva Vieira D, Bardales Escalante W, Zamora-Huamán SJ, Ordinola-Ramirez CM, Maicelo Quintana JL, Lopez Lapa RM. Exploring the microbiome of two uterine sites in cows. Sci Rep 2023; 13:18768. [PMID: 37907617 PMCID: PMC10618249 DOI: 10.1038/s41598-023-46093-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/27/2023] [Indexed: 11/02/2023] Open
Abstract
Bacterial communities in the mammalian reproductive system can be rich and diverse, differing in structure and quantity depending on location. In addition, its microbiome is associated with the state of health of this tract and reproductive success. This study evaluated the microbiome composition of the uterine body (UB) and uterine horn mucosa (UH) samples using 16S rRNA sequencing of samples extracted from cows in the Amazon region. It was observed that four main phyla were shared between the uterine sites: Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Linear discriminant analysis effect size and heat tree analysis showed that members of Lachnospiraceae (NK3A20 group) and Oscillospiraceae were significantly more abundant in the UB than in UH. In addition, there are more unique genera in the UB than in the UH. A higher bacterial load in UB than in UH is expected because of the exposure to external factors of UB. However, comparing the site's communities through beta diversity did not generate well-defined clustering. Thus, it can be attributed to the closeness of the sites, which would make the niches similar ecologically and microbiologically. Therefore, this research provides knowledge to understand biomarkers in the prior reproduction period.
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Han S, Cicek AF, Tokmak A, Yildirir Ustun T, Ercan Gokay N, Uludag MO, Demirel MA. Effects of Resveratrol on Receptor Expression and Serum Levels of Estrogen and Progesterone in the Rat Endometritis Model. Reprod Sci 2021; 28:2610-2622. [PMID: 33966185 DOI: 10.1007/s43032-021-00586-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 04/15/2021] [Indexed: 11/24/2022]
Abstract
Endometritis is characterized by inflammation of the endometrial lining that leads to reduced reproductive potential. Restoring the impaired hormonal balance is an important component of endometritis treatment. The purpose of the current study was to evaluate the effects of resveratrol on estrogen and progesterone hormone status in endometritis. Mature female Sprague Dawley rats were used, and endometritis was induced by intrauterine infusion of Escherichia coli. Animals were treated with resveratrol alone or combined with marbofloxacin. Compared to the non-treated endometritis group, resveratrol treatment reduced serum oestradiol levels, increased serum progesterone levels, enhanced estrogen receptor (ER) expression in the uterine stroma, decreased ESR1 gene expression, and raised ESR2 gene expression. Resveratrol administration combined with marbofloxacin also increased ER expression in the uterine gland and progesterone receptor expression in the uterine epithelium. The findings of this study suggest that the actions of resveratrol on progesterone levels and estrogen receptor expression might be responsible for its beneficial effect in rats with endometritis.
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Callan T, Woodcock S, Huston WM. Ascension of Chlamydia is moderated by uterine peristalsis and the neutrophil response to infection. PLoS Comput Biol 2021; 17:e1009365. [PMID: 34492008 PMCID: PMC8448331 DOI: 10.1371/journal.pcbi.1009365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 09/17/2021] [Accepted: 08/19/2021] [Indexed: 11/19/2022] Open
Abstract
Chlamydia trachomatis is a common sexually transmitted infection that is associated with a range of serious reproductive tract sequelae including in women Pelvic Inflammatory Disease (PID), tubal factor infertility, and ectopic pregnancy. Ascension of the pathogen beyond the cervix and into the upper reproductive tract is thought to be necessary for these pathologies. However, Chlamydia trachomatis does not encode a mechanism for movement on its genome, and so the processes that facilitate ascension have not been elucidated. Here, we evaluate the factors that may influence chlamydial ascension in women. We constructed a mathematical model based on a set of stochastic dynamics to elucidate the moderating factors that might influence ascension of infections in the first month of an infection. In the simulations conducted from the stochastic model, 36% of infections ascended, but only 9% had more than 1000 bacteria ascend. The results of the simulations indicated that infectious load and the peristaltic contractions moderate ascension and are inter-related in impact. Smaller initial loads were much more likely to ascend. Ascension was found to be dependent on the neutrophil response. Overall, our results indicate that infectious load, menstrual cycle timing, and the neutrophil response are critical factors in chlamydial ascension in women.
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Bogado Pascottini O, Spricigo JFW, Van Schyndel SJ, Mion B, Rousseau J, Weese JS, LeBlanc SJ. Effects of parity, blood progesterone, and non-steroidal anti-inflammatory treatment on the dynamics of the uterine microbiota of healthy postpartum dairy cows. PLoS One 2021; 16:e0233943. [PMID: 33606706 PMCID: PMC7895344 DOI: 10.1371/journal.pone.0233943] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 01/28/2021] [Indexed: 01/10/2023] Open
Abstract
This study evaluated the effects of treatment with meloxicam (a non-steroidal anti-inflammatory drug), parity, and blood progesterone concentration on the dynamics of the uterine microbiota of 16 clinically healthy postpartum dairy cows. Seven primiparous and 9 multiparous postpartum Holstein cows either received meloxicam (0.5 mg/kg SC, n = 7 cows) once daily for 4 days (10 to 13 days in milk (DIM)) or were untreated (n = 9 cows). Endometrial cytology samples were collected by cytobrush at 10, 21, and 35 DIM, from which the microbiota analysis was conducted using 16S rRNA gene sequence analysis. A radioimmunoassay was used to measure progesterone concentration in blood serum samples at 35 DIM and cows were classified as ˃ 1 ng/mL (n = 10) or ≤ 1 ng/mL (n = 6). Alpha diversity for bacterial genera (Chao1, Shannon-Weiner, and Camargo’s evenness indices) were not affected by DIM, meloxicam treatment, parity, or progesterone category. For beta diversity (genera level), principal coordinate analysis (Bray-Curtis) showed differences in microbiota between parity groups. At the phylum level, the relative abundance of Actinobacteria was greater in primiparous than multiparous cows. At the genus level, there was lesser relative abundance of Bifidobacterium, Lactobacillus, Neisseriaceae, Paracoccus, Staphylococcus, and Streptococcus and greater relative abundance of Bacillus and Fusobacterium in primiparous than multiparous cows. Bray-Curtis dissimilarity did not differ by DIM at sampling, meloxicam treatment, or progesterone category at 35 DIM. In conclusion, uterine bacterial composition was not different at 10, 21, or 35 DIM, and meloxicam treatment or progesterone category did not affect the uterine microbiota in clinically healthy postpartum dairy cows. Primiparous cows presented a different composition of uterine bacteria than multiparous cows. The differences in microbiota associated with parity might be attributable to changes that occur consequent to the first calving, but this hypothesis should be investigated further.
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Ghoneim IM, Al-Ahmad JA, Fayez MM, El-Sabagh IM, Humam NAA, Al-Eknah MM. Characterization of microbes associated with cervico-vaginal adhesion in the reproductive system of camels (Camelus dromedaries). Trop Anim Health Prod 2021; 53:132. [PMID: 33469798 DOI: 10.1007/s11250-020-02538-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 12/17/2020] [Indexed: 11/30/2022]
Abstract
Vaginal and cervical adhesions are severe long-standing reproductive disorder in dromedaries and consequently result in a high culling rate. This study was designed to compare the microbial communities of the vaginae, cervices, and uteri of normal (n = 10) camels versus camels suffering from cervico-vaginal adhesion (n = 23). Vaginal, cervical, and uterine swab samples were collected from control and affected animals. Furthermore, serum samples were obtained for serological testing of Chlamydiosis and Coxiellosis. For bacteriological and fungal examination, swab samples were plated on Columbia and Saboraud's dextrose agar, respectively. Polymerase chain reaction (PCR) assay was applied to samples expressed seropositive for Chlamydiosis. Vaginal swab bacterial cultures showed that the affected animals were significantly infected with Staphylococcus aureus (P = 0.0322, CI: 0.25-0.95) than the control, while mycological cultures showed that both control and affected animals were infected with Cryptococcus and Candida albicans. Corynebacterium spp. (22.7%), Pseudomonas spp. (4.5%), Klebsiella spp. (9.1%), T. pyogenes (18.2%), and anaerobic bacteria (Fusobacterium necrophorum and Clostridium spp.; 34.78%) were also identified in affected animals. Cervical samples from affected animals were distinguished by the existence of S. aureus (27.8%), Klebsiella spp. (5.6%), Corynebacterium spp. (22.2%), Cryptococcus (16.7%), Proteus spp. (11.1% (, T. pyogenes (11.1%), Pseudomonas spp. (5.6%), and Fusobacterium necrophorum (17.4%). Uterine samples from affected animals were characterized by the presence of S. aureus (22.2%), Streptococcus (22.2%), Corynebacterium spp. (11.1%), E. coli (11.1%), and Pseudomonas spp. (11.1%). Anaerobic bacteria were not isolated from control nor affected animals. Enzyme immunoassays revealed that 50% and 34.8% of the control and affected animals were positive for Coxiella burnetii, respectively, Chlamydia was detected in 43.5% of samples from affected animals, only 60% of which were confirmed positive. These results show that microbial communities linked with cervico-vaginal adhesion in dromedary camels are likely to be polymicrobial. The findings of this study are helpful in designing antimicrobial therapies toward reducing the incidence for cervico-vaginal adhesion.
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Silverstein RB, Mysorekar IU. Group therapy on in utero colonization: seeking common truths and a way forward. MICROBIOME 2021; 9:7. [PMID: 33436100 PMCID: PMC7805186 DOI: 10.1186/s40168-020-00968-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/06/2020] [Indexed: 05/04/2023]
Abstract
The human microbiome refers to the genetic composition of microorganisms in a particular location in the human body. Emerging evidence over the past many years suggests that the microbiome constitute drivers of human fate almost at par with our genome and epigenome. It is now well accepted after decades of disbelief that a broad understanding of human development, health, physiology, and disease requires understanding of the microbiome along with the genome and epigenome. We are learning daily of the interdependent relationships between microbiome/microbiota and immune responses, mood, cancer progression, response to therapies, aging, obesity, antibiotic usage, and overusage and much more. The next frontier in microbiome field is understanding when does this influence begin? Does the human microbiome initiate at the time of birth or are developing human fetuses already primed with microbes and their products in utero. In this commentary, we reflect on evidence gathered thus far on this question and identify the unknown common truths. We present a way forward to continue understanding our microbial colleagues and our interwoven fates.
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Blaser MJ, Devkota S, McCoy KD, Relman DA, Yassour M, Young VB. Lessons learned from the prenatal microbiome controversy. MICROBIOME 2021; 9:8. [PMID: 33436098 PMCID: PMC7805060 DOI: 10.1186/s40168-020-00946-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/16/2020] [Indexed: 05/24/2023]
Abstract
For more than a century, the prenatal environment was considered sterile. Over the last few years, findings obtained with next-generation sequencing approaches from samples of the placenta, the amniotic fluid, meconium, and even fetal tissues have challenged the dogma of a sterile womb, and additional reports have emerged that used culture, microscopy, and quantitative PCR to support the presence of a low-biomass microbial community at prenatal sites. Given the substantial implications of prenatal exposure to microbes for the development and health of the host, the findings have gathered substantial interest from academics, high impact journals, the public press, and funding agencies. However, an increasing number of studies have challenged the prenatal microbiome identifying contamination as a major issue, and scientists that remained skeptical have pointed to inconsistencies with in utero colonization, the impact of c-sections on early microbiome assembly, and the ability to generate germ-free mammals. A lively academic controversy has emerged on the existence of the wider importance of prenatal microbial communities. Microbiome has asked experts to discuss these issues and provide their thoughts on the implications. To allow for a broader perspective of this discussion, we have specifically selected scientists, who have a long-standing expertise in microbiome sciences but who have not directly been involved in the debate so far.
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Walter J, Hornef MW. A philosophical perspective on the prenatal in utero microbiome debate. MICROBIOME 2021; 9:5. [PMID: 33436093 PMCID: PMC7805158 DOI: 10.1186/s40168-020-00979-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 11/17/2020] [Indexed: 05/16/2023]
Abstract
Within the last 6 years, a research field has emerged that focuses on the characterization of microbial communities in the prenatal intrauterine environment of humans and their putative role in human health. However, there is considerable controversy around the existence of such microbial populations. The often contentious debate is primarily focused on technical aspects of the research, such as difficulties to assure aseptic sampling and to differentiate legitimate signals in the data from contamination. Although such discussions are clearly important, we feel that the problems with the prenatal microbiome field go deeper. In this commentary, we apply a philosophical framework to evaluate the foundations, experimental approaches, and interpretations used by scientists on both sides of the debate. We argue that the evidence for a "sterile womb" is based on a scientific approach that aligns well with important principles of the philosophy of science as genuine tests of the hypothesis and multiple angles of explanatory considerations were applied. In contrast, research in support of the "in utero colonization hypothesis" is solely based on descriptive verifications that do not provide explanatory insight, which weakens the evidence for a prenatal intrauterine microbiome. We propose that a reflection on philosophical principles can inform not only the debate on the prenatal intrauterine microbiome but also other disciplines that attempt to study low-biomass microbial communities.
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Fricke WF, Ravel J. Microbiome or no microbiome: are we looking at the prenatal environment through the right lens? MICROBIOME 2021; 9:9. [PMID: 33436081 PMCID: PMC7805159 DOI: 10.1186/s40168-020-00947-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 11/16/2020] [Indexed: 05/23/2023]
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