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- Fransson, Emma, PhD, 1973-, et al.
(författare)
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Cohort profile : the Swedish Maternal Microbiome project (SweMaMi) - assessing the dynamic associations between the microbiome and maternal and neonatal adverse events
- 2022
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Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The Swedish Maternal Microbiome (SweMaMi) project was initiated to better understand the dynamics of the microbiome in pregnancy, with longitudinal microbiome sampling, shotgun metagenomics, extensive questionnaires and health registry linkage. Participants Pregnant women were recruited before the 20th gestational week during 2017-2021 in Sweden. In total, 5439 pregnancies (5193 unique women) were included. For 3973 pregnancies (73%), samples were provided at baseline, and for 3141 (58%) at all three timepoints (second and third trimester and postpartum). In total, 38 591 maternal microbiome samples (vaginal, faecal and saliva) and 3109 infant faecal samples were collected. Questionnaires were used to collect information on general, reproductive and mental health, diet and lifestyle, complemented by linkage to the nationwide health registries, also used to follow up the health of the offspring (up to age 10). Findings to date The cohort is fairly representative for the total Swedish pregnant population (data from 2019), with 41% first-time mothers. Women with university level education, born in Sweden, with normal body mass index, not using tobacco-products and aged 30-34 years were slightly over-represented. Future plans The sample and data collection were finalised in November 2021. The next steps are the characterisation of the microbial DNA and linkage to the health and demographic information from the questionnaires and registries. The role of the microbiome on maternal and neonatal outcomes and early-childhood diseases will be explored (including preterm birth, miscarriage) and the role and interaction of other risk factors and confounders (including endometriosis, polycystic ovarian syndrome, diet, drug use). This is currently among the largest pregnancy cohorts in the world with longitudinal design and detailed and standardised microbiome sampling enabling follow-up of both mothers and children. The findings are expected to contribute greatly to the field of reproductive health focusing on pregnancy and neonatal outcomes.
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| 2. |
- Paulander, Wilhelm, et al.
(författare)
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Caenorhabditis elegans as a model to determine fitness of antibiotic-resistant Salmonella enterica serovar typhimurium
- 2007
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 51:2, s. 766-769
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Tidskriftsartikel (refereegranskat)abstract
- We used the ability of Salmonella enterica serovar Typhimurium to colonize the gut of Caenorhabditis elegans to measure the fitness costs imposed by antibiotic resistance mutations. The fitness costs determined in the nematode were similar to those measured in mice, validating its use as a simple host model to evaluate bacterial fitness.
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| 3. |
- Sandegren, Linus, et al.
(författare)
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Genomic Stability over 9 Years of an Isoniazid Resistant Mycobacterium tuberculosis Outbreak Strain in Sweden
- 2011
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:1, s. e16647-
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Tidskriftsartikel (refereegranskat)abstract
- In molecular epidemiological studies of drug resistant Mycobacterium tuberculosis (TB) in Sweden a large outbreak of an isoniazid resistant strain was identified, involving 115 patients, mainly from the Horn of Africa. During the outbreak period, the genomic pattern of the outbreak strain has stayed virtually unchanged with regard to drug resistance, IS6110 restriction fragment length polymorphism and spoligotyping patterns. Here we present the complete genome sequence analyses of the index isolate and two isolates sampled nine years after the index case as well as experimental data on the virulence of this outbreak strain. Even though the strain has been present in the community for nine years and passaged between patients at least five times in-between the isolates, we only found four single nucleotide polymorphisms in one of the later isolates and a small (4 amino acids) deletion in the other compared to the index isolate. In contrast to many other evolutionarily successful outbreak lineages (e. g. the Beijing lineage) this outbreak strain appears to be genetically very stable yet evolutionarily successful in a low endemic country such as Sweden. These findings further illustrate that the rate of genomic variation in TB can be highly strain dependent, something that can have important implications for epidemiological studies as well as development of resistance.
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| 4. |
- Sterpu, Irene, et al.
(författare)
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No evidence for a placental microbiome in human pregnancies at term
- 2021
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Ingår i: American Journal of Obstetrics and Gynecology. - : Elsevier. - 0002-9378 .- 1097-6868. ; 224:3, s. 296.e1-296.e23
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Tidskriftsartikel (refereegranskat)abstract
- Background: The placenta plays an important role in the modulation of pregnancy immunity; however, there is no consensus regarding the existence of a placental microbiome in healthy full-term pregnancies.Objective: This study aimed to investigate the existence and origin of a placental microbiome.Study Design: A cross-sectional study comparing samples (3 layers of placental tissue, amniotic fluid, vernix caseosa, and saliva, vaginal, and rectal samples) from 2 groups of full-term births: 50 women not in labor with elective cesarean deliveries and 26 with vaginal deliveries. The comparisons were performed using polymerase chain reaction amplification and DNA sequencing techniques and bacterial culture experiments.Result: There were no significant differences regarding background characteristics between women who delivered by elective cesarean and those who delivered vaginally. Quantitative measurements of bacterial content in all 3 placental layers (quantitative polymerase chain reaction of the 16S ribosomal RNA gene) did not show any significant difference among any of the sample types and the negative controls. Here, 16S ribosomal RNA gene sequencing of the maternal side of the placenta could not differentiate between bacteria in the placental tissue and contamination of the laboratory reagents with bacterial DNA. Probe-specific quantitative polymerase chain reaction for bacterial taxa suspected to be present in the placenta could not detect any statistically significant difference between the 2 groups. In bacterial cultures, substantially more bacteria were observed in the placenta layers from vaginal deliveries than those from cesarean deliveries. In addition, 16S ribosomal RNA gene sequencing of bacterial colonies revealed that most of the bacteria that grew on the plates were genera typically found in human skin; moreover, it revealed that placentas delivered vaginally contained a high prevalence of common vaginal bacteria. Bacterial growth inhibition experiments indicated that placental tissue may facilitate the inhibition of bacterial growth.Conclusion: We found no evidence to support the existence of a placental microbiome in our study of 76 term pregnancies, which used polymerase chain reaction amplification and sequencing techniques and bacterial culture experiments. Incidental findings of bacterial species could be due to contamination or to low-grade bacterial presence in some locations; such bacteria do not represent a placental microbiome per se.
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