Background: Next-generation 16S ribosomal RNA gene sequencing is widely used to determine the relative composition of the mammalian gut microbiomes. However, in the absence of a reference, this does not reveal alterations in absolute abundance of specific operational taxonomic units if microbial loads vary across specimens.
Results: Here we suggest the spiking of exogenous bacteria into crude specimens to quantify ratios of absolute bacterial abundances. We use the 16S rDNA read counts of the spike-in bacteria to adjust the read counts of endogenous bacteria for changes in total microbial loads. Using a series of dilutions of pooled faecal samples from mice containing defined amounts of the spike-in bacteria Salinibacter ruber, Rhizobium radiobacter and Alicyclobacillus acidiphilus, we demonstrate that spike-in-based calibration to microbial loads allows accurate estimation of ratios of absolute endogenous bacteria abundances. Applied to stool specimens of patients undergoing allogeneic stem cell transplantation, we were able to determine changes in both relative and absolute abundances of various phyla, especially the genus Enterococcus, in response to antibiotic treatment and radio-chemotherapeutic conditioning.
Conclusion: Exogenous spike-in bacteria in gut microbiome studies enable estimation of ratios of absolute OTU abundances, providing novel insights into the structure and the dynamics of intestinal microbiomes.
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http://dx.doi.org/10.1186/s40168-016-0175-0 | DOI Listing |
BMC Microbiol
November 2024
Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany.
Background: Previous studies have identified structurally diverse N-acyl amino acid methyl esters (NAMEs) in culture extracts of Roseovarius tolerans EL-164 (Roseobacteraceae). NAMEs are structural analogues of the common signaling compounds N-acyl homoserine lactones (AHLs), but do not participate in AHL-mediated signaling. NAMEs show minor antialgal and antimicrobial activity, but whether this activity serves as the primary ecological role remains unclear.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
January 2025
Laboratory of Soil and Environmental Microbiology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Fukuoka, Japan.
Lactic acid bacteria (LAB) shape diverse communities in fermented foods. Developing comprehensive quantification methods for community structure will revolutionize our understanding of food LAB microbiome. For this purpose, 16S rRNA gene amplicon-based quantification, using spiked exogenous bacterial cells as an internal standard, shows potential for comprehensiveness and accuracy.
View Article and Find Full Text PDFSci Rep
November 2024
Aquatic Environmental Biotechnology Division, ICAR-Central Inland Fisheries Research Institute, Barrackpore, 700120, Kolkata, India.
Intervirology
October 2024
Department of Microbiology, Viral Research Diagnosis Laboratory, ICMR-Regional Medical Research Centre, Gorakhpur, India.
Introduction: Acute hemorrhagic conjunctivitis (AHC) outbreaks are caused mostly by viruses. During July-August 2023, there was a sudden spike in acute hemorrhage conjunctivitis cases in Eastern Uttar Pradesh, India. To identify the etiological and gain molecular epidemiology of the agent, the study was conducted.
View Article and Find Full Text PDFWater Res
December 2024
Department of Biosystems Science and Engineering, ETH Zurich, CH-4056 Basel, Switzerland; SIB Swiss Institute of Bioinformatics, CH-1015 Lausanne, Switzerland. Electronic address:
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