1.
Andersson, A. F., et al.
(författare)
Comparative analysis of human gut microbiota by barcoded pyrosequencing
2008
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:7
Tidskriftsartikel (refereegranskat) abstract
Humans host complex microbial communities believed to contribute to health maintenance and, when in imbalance, to the development of diseases. Determining the microbial composition in patients and healthy controls may thus provide novel therapeutic targets. For this purpose, high-throughput, cost-effective methods for microbiota characterization are needed. We have employed 454-pyrosequencing of a hyper-variable region of the 16S rRNA gene in combination with sample-specific barcode sequences which enables parallel in-depth analysis of hundreds of samples with limited sample processing. In silico modeling demonstrated that the method correctly describes microbial communities down to phylotypes below the genus level. Here we applied the technique to analyze microbial communities in throat, stomach and fecal samples. Our results demonstrate the applicability of barcoded pyrosequencing as a high-throughput method for comparative microbial ecology.
2.
Bjerre, RD, et al.
(författare)
Effects of sampling strategy and DNA extraction on human skin microbiome investigations
2019
Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1, s. 17287-
Tidskriftsartikel (refereegranskat) abstract
The human skin is colonized by a wide array of microorganisms playing a role in skin disorders. Studying the skin microbiome provides unique obstacles such as low microbial biomass. The objective of this study was to establish methodology for skin microbiome analyses, focusing on sampling technique and DNA extraction. Skin swabs and scrapes were collected from 9 healthy adult subjects, and DNA extracted using 12 commercial kits. All 165 samples were sequenced using the 16S rRNA gene. Comparing the populations captured by eSwabs and scrapes, 99.3% of sequences overlapped. Using eSwabs yielded higher consistency. The success rate of library preparation applying different DNA extraction kits ranged from 39% to 100%. Some kits had higher Shannon alpha-diversity. Metagenomic shotgun analyses were performed on a subset of samples (N = 12). These data indicate that a reduction of human DNA from 90% to 57% is feasible without lowering the success of 16S rRNA library preparation and without introducing taxonomic bias. Using swabs is a reliable technique to investigate the skin microbiome. DNA extraction methodology is crucial for success of sequencing and adds a substantial amount of variation in microbiome analyses. Reduction of host DNA is recommended for interventional studies applying metagenomics.
3.
Enroth, Helena, et al.
(författare)
Infectious Diseases : Helicobacter pylori
2015
Ingår i: Reference Module in Biomedical Sciences. - : Elsevier. - 9780128012383
Bokkapitel (övrigt vetenskapligt/konstnärligt) abstract
Abstract Helicobacter pylori infection is one of the most common human infections in the world. The bacteria cause peptic ulcer disease and their infection is an important factor for gastric cancer development. The bacteria are transmitted from person to person within families, with young children most often infected. The bacteria reside in the stomach for a lifetime if untreated by antimicrobial agents. Many virulence factors are known that contribute to the persistence of the bacteria in the stomach, and the bacteria harbors a pathogenicity island in its genome. The discovery of H. pylori as a cause of gastritis in the stomach led to the Nobel Prize in Physiology or Medicine 2005.
4.
Jakobsson, H E, et al.
(författare)
Short-term antibiotic treatment has differing long-term impacts on the human throat and gut microbiome
2010
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:3, s. e9836-
Tidskriftsartikel (refereegranskat) abstract
Antibiotic administration is the standard treatment for the bacterium Helicobacter pylori, the main causative agent of peptic ulcer disease and gastric cancer. However, the long-term consequences of this treatment on the human indigenous microbiota are relatively unexplored. Here we studied short- and long-term effects of clarithromycin and metronidazole treatment, a commonly used therapy regimen against H. pylori, on the indigenous microbiota in the throat and in the lower intestine. The bacterial compositions in samples collected over a four-year period were monitored by analyzing the 16S rRNA gene using 454-based pyrosequencing and terminal-restriction fragment length polymorphism (T-RFLP). While the microbial communities of untreated control subjects were relatively stable over time, dramatic shifts were observed one week after antibiotic treatment with reduced bacterial diversity in all treated subjects in both locations. While the microbiota of the different subjects responded uniquely to the antibiotic treatment some general trends could be observed; such as a dramatic decline in Actinobacteria in both throat and feces immediately after treatment. Although the diversity of the microbiota subsequently recovered to resemble the pre treatment states, the microbiota remained perturbed in some cases for up to four years post treatment. In addition, four years after treatment high levels of the macrolide resistance gene erm(B) were found, indicating that antibiotic resistance, once selected for, can persist for longer periods of time than previously recognized. This highlights the importance of a restrictive antibiotic usage in order to prevent subsequent treatment failure and potential spread of antibiotic resistance.
5.
Kampmann, C., et al.
(författare)
Composition of human faecal microbiota in resistance to Campylobacter infection
2016
Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 22:1, s. 1-61
Tidskriftsartikel (refereegranskat) abstract
In mice, specific species composition of gut microbiota enhances susceptibility to Campylobacter jejuni but little is known about the specific composition of the human gut microbiota in providing protection from infections caused by enteropathogens. Healthy adult individuals, who travelled in groups from Sweden to destinations with an estimated high risk for acquisition of Campylobacter infection, were enrolled. Faecal samples, collected before travelling and after returning home, were cultured for bacterial enteropathogens, and analysed for Campylobacter by PCR and for the species composition of the microbiota by 16S amplicon massive parallel sequencing. The microbiota compositions were compared between persons who became infected during their travel and those who did not. A total of 63 participants completed the study; 14 became infected with Campylobacter, two with Salmonella and 47 remained negative for the enteropathogens tested. After exclusion of samples taken after antimicrobial treatment, 49 individuals were included in the final analyses. Intra-individual stability of the microbiota was demonstrated for samples taken before travelling. The original diversity of the faecal microbiota was significantly lower among individuals who later became infected compared with those who remained uninfected. The relative abundances of bacteria belonging to the family Lachnospiraceae, and more specifically its two genera Dorea and Coprococcus, were significantly higher among those who remained uninfected. The travel-related infection did not significantly modify the faecal microbiota composition. Species composition of human gut microbiota is important for colonization resistance to Campylobacter infection. Especially individuals with a lower diversity are more susceptible to Campylobacter infection.
6.
7.
Olsson, Lisa M., 1984, et al.
(författare)
Dynamics of the normal gut microbiota: A longitudinal one-year population study in Sweden
2022
Ingår i: Cell Host and Microbe. - : Elsevier BV. - 1931-3128 .- 1934-6069. ; 30:5
Tidskriftsartikel (refereegranskat) abstract
Temporal dynamics of the gut microbiota potentially limit the identification of microbial features associated with health status. Here, we used whole-genome metagenomic and 16S rRNA gene sequencing to characterize the intra- and inter-individual variations of gut microbiota composition and functional potential of a disease-free Swedish population (n = 75) over one year. We found that 23% of the total compositional variance was explained by intra-individual variation. The degree of intra-individual compositional variability was negatively associated with the abundance of Faecalibacterium prausnitzii (a butyrate producer) and two Bifidobacterium species. By contrast, the abundance of facultative anaerobes and aerotolerant bacteria such as Escherichia coli and Lactobacillus acidophilus varied extensively, independent of compositional stability. The contribution of intra-individual variance to the total variance was greater for functional pathways than for microbial species. Thus, reliable quantification of microbial features requires repeated samples to address the issue of intra-individual variations of the gut microbiota.
8.
Vaga, S., et al.
(författare)
Compositional and functional differences of the mucosal microbiota along the intestine of healthy individuals
2020
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
Tidskriftsartikel (refereegranskat) abstract
Gut mucosal microbes evolved closest to the host, developing specialized local communities. There is, however, insufficient knowledge of these communities as most studies have employed sequencing technologies to investigate faecal microbiota only. This work used shotgun metagenomics of mucosal biopsies to explore the microbial communities' compositions of terminal ileum and large intestine in 5 healthy individuals. Functional annotations and genome-scale metabolic modelling of selected species were then employed to identify local functional enrichments. While faecal metagenomics provided a good approximation of the average gut mucosal microbiome composition, mucosal biopsies allowed detecting the subtle variations of local microbial communities. Given their significant enrichment in the mucosal microbiota, we highlight the roles of Bacteroides species and describe the antimicrobial resistance biogeography along the intestine. We also detail which species, at which locations, are involved with the tryptophan/indole pathway, whose malfunctioning has been linked to pathologies including inflammatory bowel disease. Our study thus provides invaluable resources for investigating mechanisms connecting gut microbiota and host pathophysiology.
9.
