The colibactin-producing Escherichia coli alters the tumor microenvironment to immunosuppressive lipid overload facilitating colorectal cancer progression and chemoresistance.

Intratumoral bacteria flexibly contribute to cellular and molecular tumor heterogeneity for supporting cancer recurrence through poorly understood mechanisms. Using spatial metabolomic profiling technologies and 16SrRNA sequencing, we herein report that right-sided colorectal tumors are predominantly populated with Colibactin-producing Escherichia coli (CoPEC) that are locally establishing a high-glycerophospholipid microenvironment with lowered immunogenicity. It coincided with a reduced infiltration of CD8+ T lymphocytes that produce the cytotoxic cytokines IFN-γ where invading bacteria have been geolocated. Mechanistically, the accumulation of lipid droplets in infected cancer cells relied on the production of colibactin as a measure to limit genotoxic stress to some extent. Such heightened phosphatidylcholine remodeling by the enzyme of the Land's cycle supplied CoPEC-infected cancer cells with sufficient energy for sustaining cell survival in response to chemotherapies. This accords with the lowered overall survival of colorectal patients at stage III-IV who were colonized by CoPEC when compared to patients at stage I-II. Accordingly, the sensitivity of CoPEC-infected cancer cells to chemotherapies was restored upon treatment with an acyl-CoA synthetase inhibitor. By contrast, such metabolic dysregulation leading to chemoresistance was not observed in human colon cancer cells that were infected with the mutant strain that did not produce colibactin (11G5∆ClbQ). This work revealed that CoPEC locally supports an energy trade-off lipid overload within tumors for lowering tumor immunogenicity. This may pave the way for improving chemoresistance and subsequently outcome of CRC patients who are colonized by CoPEC.

How Did Institut Pasteur's NGS Core Facility, Biomics, Manage the Coronavirus Disease 2019 Crisis?

In 2020, research entities at the Institut Pasteur (IP) in Paris, as elsewhere around the world, were closed because of the coronavirus disease 2019 (COVID-19) pandemic. However, IP core facilities, laboratories, services, and departments working on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and priority projects were authorized to continue working both on site and remotely. Given the importance of its role in SARS-CoV-2 genome-sequencing initiatives, the IP Biomics core facility was fully functional during the first (i.e., March-June 2020) and second (i.e., November-December 2020) national lockdowns. We describe here how Biomics successfully implemented an emergency management plan to deal with this health crisis. We highlight the internal deployment of the institutional business continuity plan (BCP) through a series of actions. We also address the impact of the COVID-19 crisis on Biomics staff and collaborators. The added value of quality management and the limitations of risk management systems are discussed. Finally, we suggest that the Biomics infrastructure and the BCP described here could be used for benchmarking purposes, for other next-generation sequencing core facilities wishing to implement/improve their processes, and for future major crisis management.

SHAMAN: a user-friendly website for metataxonomic analysis from raw reads to statistical analysis.

BACKGROUND: Comparing the composition of microbial communities among groups of interest (e.g., patients vs healthy individuals) is a central aspect in microbiome research. It typically involves sequencing, data processing, statistical analysis and graphical display. Such an analysis is normally obtained by using a set of different applications that require specific expertise for installation, data processing and in some cases, programming skills. RESULTS: Here, we present SHAMAN, an interactive web application we developed in order to facilitate the use of (i) a bioinformatic workflow for metataxonomic analysis, (ii) a reliable statistical modelling and (iii) to provide the largest panel of interactive visualizations among the applications that are currently available. SHAMAN is specifically designed for non-expert users. A strong benefit is to use an integrated version of the different analytic steps underlying a proper metagenomic analysis. The application is freely accessible at http://shaman.pasteur.fr/ , and may also work as a standalone application with a Docker container (aghozlane/shaman), conda and R. The source code is written in R and is available at https://github.com/aghozlane/shaman . Using two different datasets (a mock community sequencing and a published 16S rRNA metagenomic data), we illustrate the strengths of SHAMAN in quickly performing a complete metataxonomic analysis. CONCLUSIONS: With SHAMAN, we aim at providing the scientific community with a platform that simplifies reproducible quantitative analysis of metagenomic data.

Multilocus sequence analysis of the genus Citrobacter and description of Citrobacter pasteurii sp. nov.

Strains originating from various sources and classified as members of the genus Citrobacter within the family Enterobacteriaceae were characterized by sequencing internal portions of genes rpoB, fusA, pyrG and leuS, 16S rRNA gene sequencing, average nucleotide identity (ANI) of genomic sequences and biochemical tests. Phylogenetic analysis based on the four housekeeping genes showed that the 11 species of the genus Citrobacter with validly published names are well demarcated. Strains CIP 55.13(T) and CIP 55.9 formed a distinct branch associated with Citrobacter youngae. The ANI between CIP 55.9 and CIP 55.13(T) was 99.19%, whereas it was 94.75% between CIP 55.13(T) and strain CIP 105016(T) of the species C. youngae, the most closely related species. Biochemical characteristics consolidated the fact that the two isolates represent a separate species, for which the name Citrobacter pasteurii sp. nov. is proposed. The type strain is CIP 55.13(T) ( =DSM 28879(T) =Na 1a(T)).

Lactobacillus pasteurii sp. nov. and Lactobacillus hominis sp. nov.

Strains 1517(T) and 61D(T) were characterized by phenotypic and molecular taxonomic methods. These Gram-positive lactic acid bacteria were homo-fermentative, facultatively anaerobic short rods. They were phylogenetically related to the genus Lactobacillus according to 16S rRNA gene sequence analysis, with 99 % similarity between strain 1517(T) and the type strain of Lactobacillus gigeriorum, and 98.6, 98.5 and 98.4 % between strain 61D(T) and Lactobacillus gasseri, Lactobacillus taiwanensis and Lactobacillus johnsonii, respectively. Multilocus sequence analysis and metabolic analysis of both strains showed variation between the two strains and their close relatives, with variation in the position of the pheS and rpoA genes. The DNA-DNA relatedness of 43.5 % between strain 1517(T) and L. gigeriorum, and 38.6, 29.9 and 39.7 % between strain 61D(T) and L. johnsonii, L. taiwanensis and L. gasseri, respectively, confirmed their status as novel species. Based on phenotypic and genotypic characteristics, two novel species of Lactobacillus are proposed: Lactobacillus pasteurii sp. nov., with 1517(T) ( = CRBIP 24.76(T) = DSM 23907(T)) as the type strain, and Lactobacillus hominis sp. nov., with 61D(T) (=CRBIP 24.179(T) = DSM 23910(T)) as the type strain.

Lactobacillus gigeriorum sp. nov., isolated from chicken crop.

In the early 1980s, a facultatively anaerobic, non-motile, short rod, designated 202(T), was isolated from a chicken crop and identified as a homofermentative lactic acid bacterium. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the strain was affiliated with the genus Lactobacillus, clustering within the Lactobacillus acidophilus-delbrueckii group. In this analysis, strain 202(T) appeared to be most closely related to the type strains of Lactobacillus intestinalis and Lactobacillus amylolyticus, with gene sequence similarities of 96.1 and 96.2 %, respectively. Strain 202(T) was found to differ from these two species, however, when investigated by multilocus sequence analysis, and it also differed in terms of some of its metabolic properties. On the basis of these observations, strain 202(T) is considered to represent a novel species in the genus Lactobacillus, for which the name Lactobacillus gigeriorum sp. nov. is proposed; the type strain is 202(T) ( = CRBIP 24.85(T) = DSM 23908(T)).

Pseudomonas brassicacearum subsp. neoaurantiaca subsp. nov., orange-pigmented bacteria isolated from soil and the rhizosphere of agricultural plants.

A large group of 38 strains of saprophytic bacteria was isolated from soil and the rhizosphere of agricultural plants. The novel organisms were Gram-negative, aerobic, rod-shaped bacteria that produced a green fluorescent pigment, a red-orange diffusible pigment and a complex mixture of phloroglucinol derivates with antimicrobial activity. The latter have not been found in other bacteria, but are peculiar to ferns. The bacteria were vigorous denitrifiers that synthesized levan from sucrose and liquefied gelatin, but were found not to degrade aesculin, starch, agar, Tween 80 or DNA. Bacterial growth was found to occur at 4 degrees C but not at 40 degrees C. The predominant cellular fatty acids were 16 : 0, 16 : 1(n-7), 18 : 1(n-7) and 17 : 0 cyclo. The G+C content of the novel bacteria was 61.0-62.9 mol%. 16S rRNA gene sequence analysis indicated that the representative strain CIP 109457(T) had a clear affiliation with Pseudomonas sensu stricto groups, with the nearest relatives being Pseudomonas brassicacearum, P. thivervalensis, P. corrugata, P. mediterranea and P. kilonensis. DNA-DNA hybridization experiments showed that the group of isolated strains exhibited high levels of genetic relatedness (81-100 %), confirming that they are representatives of the same species. At the same time, they bound at low levels (4-46 %) with DNA of the type strains of their nearest relatives with the exception of P. brassicacearum; DNA binding of 90 % with the DNA of P. brassicacearum CIP 107059(T) suggested that the bacteria studied belong to this species. Analysis of taxonomic data indicated that the group of novel bacteria maintain a distinct phenotypic profile, allowing the description of novel subspecies within P. brassicacearum, for which the following names are proposed: Pseudomonas brassicacearum subsp. brassicacearum subsp. nov. (type strain DBK11(T) =CFBP 11706(T) =CIP 107059(T) =DSM 13227(T) =JCM 11938(T)) and Pseudomonas brassicacearum subsp. neoaurantiaca subsp. nov., with the type strain CIP 109457(T) (=ATCC 49054(T) =IMV 387(T) =VKM B-1524(T)).