Suppression of IL-17F, but not of IL-17A, provides protection against colitis by inducing Treg cells through modification of the intestinal microbiota.

The cytokines IL-17A and IL-17F have 50% amino-acid identity and bind the same receptor; however, their functional differences have remained obscure. Here we found that Il17f-/- mice resisted chemically induced colitis, but Il17a-/- mice did not, and that Il17f-/- CD45RBhiCD4+ T cells induced milder colitis in lymphocyte-deficient Rag2-/- mice, accompanied by an increase in intestinal regulatory T cells (Treg cells). Clostridium cluster XIVa in colonic microbiota capable of inducing Treg cells was increased in both Il17f-/- mice and mice given transfer Il17f-/- T cells, due to decreased expression of a group of antimicrobial proteins. There was substantial production of IL-17F, but not of IL-17A, not only by naive T cells but also by various colon-resident cells under physiological conditions. Furthermore, antibody to IL-17F suppressed the development of colitis, but antibody to IL-17A did not. These observations suggest that IL-17F is an effective target for the treatment of colitis.

Unveiling Microbial Diversity: Raman Spectroscopy's Discrimination of Clostridium and Related Genera.

In the clinical environment, the identification of phylogenetic closely related genera and species like Clostridium and Bacillus spp. is challenging. Both genera contain representatives of pathogenic and nonpathogenic species that need to be distinguished for a proper diagnostic read-out. Therefore, reliable and accurate detection methods must be employed for the correct identification of these genera and species. Despite their high pathogenicity, clostridial infections and food contaminations present significant challenges due to their unique cultivation conditions and developmental needs. Therefore, in many diagnostic protocols, the toxins are used for microbiological documentation. However, the applied laboratory methods suffer in accuracy, sometimes require large bacterial loads to provide reliable results, and cannot differentiate pathogenic from nonpathogenic strains. Here, Raman spectroscopy was employed to create an extensive Raman database consisting of pathogenic and nonpathogenic Bacillus and Clostridium species. These genera, as well as representatives of Paraclostridium and Clostridioides were specifically selected for their phylogenetic relation, cultivation conditions, and metabolic activity. A chemometric evaluation of the Raman spectra of single vegetative cells revealed a high discriminating power at the genus level. However, bacilli are considerably easier to classify at the species level than clostridia. The discrimination between the genera and species was based on their phylogeny and not their aerobic and anaerobic cultivation conditions. These encouraging results demonstrated that Raman spectroscopy coupled with chemometrics is a robust and helpful method for differentiating Clostridium species from Bacillus, Clostridioides, and Paraclostridium species. This approach has the potential to be a valuable tool in clinical diagnostics.

Genetic diversity, biofilm formation, and Vancomycin resistance of clinical Clostridium innocuum isolates.

BACKGROUND: Clostridium innocuum, previously considered a commensal microbe, is a spore-forming anaerobic bacterium. C. innocuum displays inherent resistance to vancomycin and is associated with extra-intestinal infections, antibiotic-associated diarrhea, and inflammatory bowel disease. This study seeks to establish a multilocus sequence typing (MLST) scheme to explore the correlation between C. innocuum genotyping and its potential pathogenic phenotypes. METHODS: Fifty-two C. innocuum isolates from Linkou Chang Gung Memorial Hospital (CGMH) in Taiwan and 60 sequence-available C. innocuum isolates from the National Center for Biotechnolgy Information Genome Database were included. The concentrated sequence of housekeeping genes in C. innocuum was determined by amplicon sequencing and used for MLST and phylogenetic analyses. The biofilm production activity of the C. innocuum isolates was determined by crystal violet staining. RESULTS: Of the 112 C. innocuum isolates, 58 sequence types were identified. Maximum likelihood estimation categorized 52 CGMH isolates into two phylogenetic clades. These isolates were found to be biofilm producers, with isolates in clade I exhibiting significantly higher biofilm production than isolates in clade II. The sub-inhibitory concentration of vancomycin seemed to minimally influence biofilm production by C. innocuum isolates. Nevertheless, C. innocuum embedded in the biofilm structure demonstrated resistance to vancomycin treatments at a concentration greater than 256 µg/mL. CONCLUSIONS: This study suggests that a specific genetic clade of C. innocuum produces a substantial amount of biofilm. Furthermore, this phenotype assists C. innocuum in resisting high concentrations of vancomycin, which may potentially play undefined roles in C. innocuum pathogenesis.

Clostridium omnivorum sp. nov., isolated from anoxic soil under the treatment of reductive soil disinfestation.

Reductive soil disinfestation (RSD), also known as biological soil disinfestation, is a bioremediation method used to suppress soil-borne plant pathogens by stimulating the activity of indigenous anaerobic bacteria in the soil. An anaerobic bacterial strain (E14T) was isolated from an anoxic soil sample subjected to RSD treatment and then comprehensively characterized. Cells of the strain were Gram-stain-positive, curved to sigmoid, and spore-forming rods. Cells were motile with a polar flagellum. Strain E14T grew in peptone-yeast extract broth, indicating that it utilized proteinous compounds. Strain E14T was also saccharolytic and produced acetate, isobutyrate, butyrate, isovalerate and gases (H2 and CO2) as fermentation products. The strain did not decompose any of examined polysaccharides except for starch. The major cellular fatty acids of strain E14T were iso-C15:0 and iso-C15:0 DMA. The closest relative to strain E14T, based on 16S rRNA gene sequences, was Clostridium thermarum SYSU GA15002T (96.2 %) in the Clostridiaceae. Whole-genome analysis of strain E14T showed that its genome was 4.66 Mb long with a genomic DNA G+C content of 32.5 mol%. The average nucleotide identity (ANIb) between strain E14T and C. thermarum SYSU GA15002T was 69.0 %. The presence of the genes encoding glycolysis and butyrate production via the acetyl-CoA pathway was confirmed through genome analysis. Based on the obtained phylogenetic, genomic and phenotypic data, we propose that strain E14T should be assigned to the genus Clostridium in the family Clostridiaceae as Clostridium omnivorum sp. nov. The type strain is E14T (=NBRC 115133T=DSM 114974T).

Clostridium aquiflavi sp. nov., isolated from yellow water of Nongxiangxing baijiu in the Yibin region of China.

A Gram-stain-positive, strictly anaerobic, endospore-forming and rod-shaped (0.6-0.8×2.7-13.1 µm) bacterium, designated as 5 N-1T, was isolated from a yellow water sample collected from the manufacturing process of Nongxiangxing baijiu in the Yibin region of Sichuan, PR China. Growth occurred at 15-40 °C (optimum growth at 37 °C), at pH 6.0-9.0 (optimum growth at pH 7.0) and in NaCl concentrations of 0-1 % (w/v) and ethanol concentrations of 0-2 % (v/v). The major fatty acids in strain 5 N-1T were C16 : 0, C18 : 0 and C14 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, four unidentified aminophospholipids and one unidentified lipid. Phylogenetic analysis of its 16S rRNA gene sequence indicated that strain 5 N-1T was most closely related to Clostridium weizhouense YB-6T (97.70 %) and Clostridium uliginosum DSM 12992T (97.56 %). The average nucleotide identity and digital DNA‒DNA hybridization values between strain 5 N-1T and the above two type strains were 80.89 and 80.05 % and 25.80 and 25.30 %, respectively, which were all below the species thresholds. The genome size of strain 5 N-1T was 3.5 Mbp and the DNA G+C content was 27.5 mol%. Based on the results of phenotypic and genotypic analyses, strain 5 N-1T represents a novel species of the genus Clostridium, for which the name Clostridium aquiflavi sp. nov. is proposed. The type strain is Clostridium aquiflavi 5 N-1T (=CICC 24886T=JCM 35355T).

Clostridium tanneri sp. nov., isolated from the faecal material of an alpaca.

A strictly anaerobic, Gram-stain-negative rod-shaped bacterium, designated A1-XYC3T, was isolated from the faeces of an alpaca (Lama pacos). On the basis of the results of a comparative 16S rRNA gene sequence analysis, the isolate was assigned to the genus Clostridium with the highest sequence similarities to Clostridium magnum DSM 2767T (96.8 %), Clostridium carboxidivorans P7T (96.3 %) and Clostridium aciditolerans JW/YJL-B3T (96.1 %). The average nucleotide identity between A1-XYC3T, C. magnum, C. carboxidivorans and C. aciditolerans was 77.4, 76.1 and 76.6  %, respectively. The predominant components of the cellular fatty acids of A1-XYC3T were C14 : 0, C16 : 0 and summed feature 10, containing C18:0/C17:0 cyclo. The DNA G+C content was 32.4 mol%. On the basis of biochemical, phylogenetic, genotypic and chemotaxonomic criteria, this isolate represents a novel species within Clostridium sensu stricto for which the name Clostridium tanneri sp. nov. is proposed. The type strain of this species is strain A1-XYC3T (=CCM 9376T=NRRL B-65691T).

A Case of Ocular Infection with Clostridium tertium Caused by a Salute Gun Explosion.

BACKGROUND: In February 2024, our hospital confirmed a case of ocular infection with Clostridium tertium caused by a salute gun explosion. The patient sought medical attention at our hospital due to a salute gun explosion injury in the right eye. Two days ago, a patient mistakenly believed that the fuse was not ignited when firing a salute gun. When observing, the salute gun exploded and injured his right eye. The patient immediately went to the local hos-pital for treatment. The CT scan of the local hospital showed rupture of the right eyeball. For additional diagnosis and treatment, the patient came to our hospital. The patient in this case has an acute onset, severe condition, no additional systemic diseases, and no history of drug or food allergies. METHODS: Intraocular exploration, cranial CT, local and systemic anti infection treatment. Pathogen examination items: bacterial smear, bacterial culture and identification. Venous blood test items: blood routine, liver function, kidney function, and coagulation function. RESULTS: Intraocular exploration showed conjunctival congestion and edema in the right eye, corneal haze and ede-ma, shallow anterior chamber, anterior chamber hemorrhage, and unclear intraocular structure. Clinical treatment: debridement and suturing of right eye rupture + repair of eyeball rupture + removal of intraocular foreign body + repair of superior rectus muscle detachment + anterior chamber flushing + anterior chamber shaping + suture of eyelid laceration. Pathogen examination item: Eye secretion bacterial smear (Gram staining): A large number of gram-positive bacilli were found, and the secretion bacterial culture and identification (MALDI-TOF MS): Clostridium tertium. Auxiliary examination: Blood routine (venous blood): White blood cells 10.89 x 109/L, neutrophil count 9.65 x 109/L, whole blood hypersensitive C-reactive protein 20.28 mg/L, renal function: urea 9.15 mmol/L, uric acid 428.5 µmol/L, fasting glucose 6.48 mmol/L, no further abnormalities observed. Clinical drug treatment plan: Tetanus human immunoglobulin 250 IU im, tobramycin eye drops 0.1 g ext qd, vancomycin 0.5 g ih qd, levofloxacin 0.5g ivgtt qd, aluminum magnesium suspension 15 mL po bid, potassium chloride sustained-release tablets 0.5 g po qd. After 7 days of treatment, the patient's body temperature returned to normal, conjunctival congestion and edema decreased, anterior chamber hemorrhage decreased, corneal incision closed properly, and the patient improved and was discharged. CONCLUSIONS: This article reports a case of ocular infection caused by a salute gun explosion with Clostridium tertium. Clostridium tertium was quickly and accurately identified by a mass spectrometer, and reasonable treatment measures were adopted clinically. The patient improved and was discharged. I hope that in the future, this study can provide assistance for the clinical diagnosis and treatment of special site infections caused by Clostridium tertium.

Epizootic of enterocolitis and clostridial overgrowth in NSG and NSG-related mouse strains.

While the immunodeficient status of NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) and NSG-related mice provides utility for numerous research models, it also results in increased susceptibility to opportunistic pathogens. Over a 9-week period, a high rate of mortality was reported in a housing room of NSG and NSG-related mice. Diagnostics were performed to determine the underlying etiopathogenesis. Mice submitted for evaluation included those found deceased (n = 2), cage mates of deceased mice with or without diarrhea (n = 17), and moribund mice (n = 8). Grossly, mice exhibited small intestinal and cecal dilation with abundant gas and/or digesta (n = 18), serosal hemorrhage and congestion (n = 6), or were grossly normal (n = 3). Histologically, there was erosive to ulcerative enterocolitis (n = 7) of the distal small and large intestine or widespread individual epithelial cell death with luminal sloughing (n = 13) and varying degrees of submucosal edema and mucosal hyperplasia. Cecal dysbiosis, a reduction in typical filamentous bacteria coupled with overgrowth of bacterial rods, was identified in 18 of 24 (75%) mice. Clostridium spp. and Paeniclostridium sordellii were identified in 13 of 23 (57%) and 7 of 23 (30%) mice, respectively. Clostridium perfringens (7 of 23, 30%) was isolated most frequently. Toxinotyping of C. perfringens positive mice (n = 2) identified C. perfringens type A. Luminal immunoreactivity to several clostridial species was identified within lesioned small intestine by immunohistochemistry. Clinicopathologic findings were thus associated with overgrowth of various clostridial species, though direct causality could not be ascribed. A diet shift preceding the mortality event may have contributed to loss of intestinal homeostasis.

Approaching toxigenic Clostridia from a One Health perspective.

Spore-forming pathogens have a unique capacity to thrive in diverse environments, and with temporal persistence afforded through their ability to sporulate. Their prevalence in diverse ecosystems requires a One Health approach to identify critical reservoirs and outbreak-associated transmission chains, given their capacity to freely move across soils, waterways, foodstuffs and as commensals or infecting pathogens in human and animal populations. Among anaerobic spore-formers, genomic resources for pathogens including C. botulinum, C. difficile, and C. perfringens enable our capacity to identify common and unique factors that support their persistence in diverse reservoirs and capacity to cause disease. Publicly available genomic resources for spore-forming pathogens at NCBI's Pathogen Detection program aid outbreak investigations and longitudinal monitoring in national and international programs in public health and food safety, as well as for local healthcare systems. These tools also enable research to derive new knowledge regarding disease pathogenesis, and to inform strategies in disease prevention and treatment. As global community resources, the continued sharing of strain genomic data and phenotypes further enhances international resources and means to develop impactful applications. We present examples showing use of these resources in surveillance, including capacity to assess linkages among clinical, environmental, and foodborne reservoirs and to further research investigations into factors promoting their persistence and virulence in different settings.

Clinical and microbiological characteristics of anaerobic bacteremia during 1994-2019: A Danish population-based cohort study.

OBJECTIVES: Bacteremia with anaerobic bacteria is generally a marker of severe prognosis. However, population-based data is lacking. Our aim was to describe the epidemiology and the 30-day mortality rate of anaerobic bacteremia in a Danish population-based setting. METHODS: In this population-based cohort study, all first-time episodes of anaerobic bacteremia from the North Denmark Bacteremia Research Database during 1994-2019 were identified. Information on comorbidities, discharge diagnoses, and mortality was retrieved. 30-day mortality rates were calculated and a multivariate logistic regression analysis to identify risk factors for death was performed. RESULTS: 1750 episodes with anaerobic bacteremia were identified, corresponding to an incidence rate of 12.5 per 100,000 inhabitants (increasing from 11.2 in 1994-2014 to 17.7 in 2015-2019). Of these episodes, a third were polymicrobial, and the majority (70 %) of patients had one or more comorbid conditions. Abdominal infection was the source of bacteremia in 61 % of patients, while it was unknown for 15 %. The most frequently isolated genera were Bacteroides (45 %), Clostridium (20 %) and Fusobacterium (6 %). The overall crude 30-day mortality rate was 27 %, but rates were even higher for patients of high age, with liver disease, and solid tumors. The odds ratio (OR) for 30-day mortality was 1.32 for Clostridium species, and 1.27 for polymicrobial bacteremia with aerobic bacteria. CONCLUSIONS: The incidence rate of anaerobic bacteremia increased, and the 30-day mortality rate remained high during the study period. Multiple factors influence 30-day mortality rates, including high age, liver disease, solid tumor, polymicrobial bacteremia, and bacteremia with Clostridium species.

Moving beyond microbiome-wide associations to causal microbe identification.

Microbiome-wide association studies have established that numerous diseases are associated with changes in the microbiota. These studies typically generate a long list of commensals implicated as biomarkers of disease, with no clear relevance to disease pathogenesis. If the field is to move beyond correlations and begin to address causation, an effective system is needed for refining this catalogue of differentially abundant microbes and to allow subsequent mechanistic studies. Here we demonstrate that triangulation of microbe-phenotype relationships is an effective method for reducing the noise inherent in microbiota studies and enabling identification of causal microbes. We found that gnotobiotic mice harbouring different microbial communities exhibited differential survival in a colitis model. Co-housing of these mice generated animals that had hybrid microbiotas and displayed intermediate susceptibility to colitis. Mapping of microbe-phenotype relationships in parental mouse strains and in mice with hybrid microbiotas identified the bacterial family Lachnospiraceae as a correlate for protection from disease. Using directed microbial culture techniques, we discovered Clostridium immunis, a previously unknown bacterial species from this family, that-when administered to colitis-prone mice-protected them against colitis-associated death. To demonstrate the generalizability of our approach, we used it to identify several commensal organisms that induce intestinal expression of an antimicrobial peptide. Thus, we have used microbe-phenotype triangulation to move beyond the standard correlative microbiome study and identify causal microbes for two completely distinct phenotypes. Identification of disease-modulating commensals by microbe-phenotype triangulation may be more broadly applicable to human microbiome studies.

Clostridium thailandense sp. nov., a novel CO2-reducing acetogenic bacterium isolated from peatland soil.

Some species of the genus Clostridium are efficient acetate producers and have been deemed useful for upgrading industrial biogas. An acetogenic, strictly anaerobic, Gram-stain-positive, subterminal endospore-forming bacterium designated strain PL3T was isolated from peatland soil enrichments with H2 and CO2. Cells of strain PL3T were 0.8-1.0×4.0-10.0 µm in size and rod-shaped. Growth of strain PL3T occurred at pH 6.0-7.5 (optimum, pH 7.0), at 20-40 °C (optimum, 30 °C) and with 0-1.5 % (w/v) NaCl (optimum, 0.5%). Biochemical analyses revealed that strain PL3T metabolized lactose, maltose, raffinose, rhamnose, lactic acid, sorbitol, arabinose and glycerol. Acetic acid was the predominant metabolite under anaerobic respiration with H2/CO2. The major cellular fatty acids were C16 : 0, C16 : 1 cis 9 and C17 : 0 cyc. The main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, aminolipid and aminophospholipid. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain PL3T belongs to the genus Clostridium with the highest sequence similarity to Clostridium aciditolerans DSM 17425T (98.6 %) followed by Clostridium nitrophenolicum (97.8 %). The genomic DNA G+C content of strain PL3T was 31.1 mol%.The genomic in silico DNA-DNA hybridization value between strain PL3T and C. aciditolerans DSM 17425T was 25.1 %, with an average nucleotide identity of 80.2 %. Based on phenotypic, chemotaxonomic and phylogenetic differences, strain PL3T was suggested to represent a novel species of the genus Clostridium, for which the name Clostridium thailandense sp. nov. is proposed. The type strain is PL3T (=DSM 111812T=TISTR 2984T).

Taxonomic status of the species Clostridium methoxybenzovorans Mechichi et al. 1999.

The taxonomic status of the species Clostridium methoxybenzovorans was assessed. The 16S rRNA gene sequence, whole-genome sequence and phenotypic characterizations suggested that the type strain deposited in the American Type Culture Collection (C. methoxybenzovorans ATCC 700855T) is a member of the species Eubacterium callanderi. Hence, C. methoxybenzovorans ATCC 700855T cannot be used as a reference for taxonomic study. The type strain deposited in the German Collection of Microorganism and Cell Cultures GmbH (DSM 12182T) is no longer listed in its online catalogue. Also, both the 16S rRNA gene and the whole-genome sequences of the original strain SR3T showed high sequence identity with those of Lacrimispora indolis (recently reclassified from Clostridium indolis) as the most closely related species. Analysis of the two genomes showed average nucleotide identity based on blast and digital DNA-DNA hybridization values of 98.3 and 87.9 %, respectively. Based on these results, C. methoxybenzovorans SR3T was considered to be a member of L. indolis.

Clostridium fessum sp. nov., isolated from human faeces.

An obligately anaerobic, Gram-stain-positive and spore-forming strain, SNUG30386T was isolated from a faecal sample of a healthy Korean subject. The strain formed a round ivory-coloured colony and cells were chained rods with tapered ends, approximately 2.0-2.5×0.6-0.8 µm in size. The taxonomic analysis indicated that strain SNUG30386T was within the family Lachnospiraceae. According to the 16S rRNA gene sequence similarity, the closest species to strain SNUG30386T was Clostridium symbiosum (95.6 %), followed by Enterocloster asparagiformis (94.8 %), Enterocloster clostridioformis (94.8 %) and Enterocloster lavalensis (94.6 %). The evolutionary tree based on 16S rRNA gene sequences demonstrated that strain SNUG30386T had split apart at a unique branch point far from other close relatives. Its DNA G+C content was 48.3 mol% calculated from the whole genome sequence. The major cellular fatty acids were C16 : 0 and C14 : 0. Compared to those of the closely related species, strain SNUG30386T showed distinct biochemical activities such as being unable to utilize most of carbon sources except d-glucose and l-arabinose. As a result, based on its unique phylogenetic clade and taxonomic characteristics, we conclude that strain SNUG30386T represents a novel species within the genus Clostridium, for which the name Clostridium fessum sp. nov. is proposed. The type strain of the novel species is SNUG30386T (=KCTC 15633T= JCM 32258T).

Clostridium zeae sp. nov., isolated from corn silage.

A rod-shaped, Gram-stain-negative, strictly anaerobic, catalase-negative and endospore-forming bacterial strain CSC2T was isolated from corn silage preserved in Tochigi, Japan. The strain CSC2T grew at 15-40 °C, at pH 5.0-7.7 and with up to 0.5 % (w/v) NaCl. The main cellular fatty acids were C14 : 0, C16 : 0 and C16 : 0 dimethyl acetal. The cellular polar lipids detected were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidic acid, lysophosphatidylethanolamine, phosphatidylserine, lysophosphatidylcholine and two unidentified polar lipids. Phylogenetic analysis of the 16S rRNA gene showed that strain CSC2T was a member of the genus Clostridium and closely related to Clostridium polyendosporum DSM 57272T (95.6 % gene sequence similarity) and Clostridium fallax ATCC 19400T (95.3 %). The genomic DNA G+C content of strain CSC2T was 31.1 mol% (whole genome analysis). The average nucleotide identity based on blast and digital DNA-DNA hybridization values between strain CSC2T and the type strains of phylogenetically related species were below 71 and 24 %, respectively. On the basis of the genotypic, phenotypic and chemotaxonomic characteristics, it is proposed to designate strain CSC2T as representing Clostridium zeae sp. nov. The type strain is CSC2T (=MAFF212476T=JCM 33766T=DSM 111242T).

Association of birth mode of delivery with infant faecal microbiota, potential pathobionts, and short chain fatty acids: a longitudinal study over the first year of life.

OBJECTIVE: Caesarean section (CS) interrupts mother-to-newborn microbial transfer at birth. Beyond the neonatal period, the impact of CS on offspring gut microbiota and their short-chain fatty acids (SCFAs) remains unclear. Here, we examine birth delivery mode (CS versus vaginal delivery) with the infant gut microbiota and faecal SCFAs measured 3 and 12 months after birth. DESIGN: Longitudinal study. SETTING: North Carolina. POPULATION: In 2013-15, we enrolled pregnant women and followed up their offspring for 12 months. We asked a subset of participants, enrolled over a 3-month period, to provide faecal samples at the 3- and 12-month follow-up visits. METHODS AND MAIN OUTCOMES: We sequenced the 16S rRNA V4 region with Illumina MiSeq and quantified SCFA concentrations using gas chromatography. We examined delivery mode with differential abundance of microbiota amplicon sequence variants (ASVs) using beta-binomial regression and faecal SCFAs using linear regression. We adjusted models for confounders. RESULTS: Of the 70 infants in our sample, 25 (36%) were delivered by CS. Compared with vaginal delivery, CS was associated with differential abundance of 14 infant bacterial ASVs at 3 months and 13 ASVs at 12 months (all FDR P < 0.05). Of note, CS infants had a higher abundance of the potential pathobionts Clostridium neonatale (P = 0.04) and Clostridium perfringens (P = 0.04) and a lower abundance of potentially beneficial Bifidobacterium and Bacteroides spp. (both P < 0.05) at 3 months. Other ASVs were differentially abundant at 12 months. Infants delivered by CS also had higher faecal butyrate concentration at 3 months (P < 0.005) but not at 12 months. CONCLUSIONS: Caesarean section was associated with increased butyrate excretion, decreased Bifidobacterium and Bacteroides spp., and more colonisation of the infant gut by pathobionts at 3 months of age. CS was also associated with altered gut microbiota composition, but not faecal SCFAs, at 12 months. TWEETABLE ABSTRACT: Caesarean section delivery was associated with increased butyrate excretion, decreased Bifidobacterium, and increased colonisation of the infant gut by pathobionts at 3 months of age.

Application of MALDI-TOF MS to assess clinical characteristics, risk factors, and outcomes associated with anaerobic bloodstream infection: a retrospective observational study.

BACKGROUND: Correctly identifying anaerobic bloodstream infections (BSIs) is difficult. However, a new technique, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), enables more accurate identification and appropriate treatment. Anaerobic BSIs identified by MALDI-TOF MS were retrospectively analyzed to determine the clinical and microbiological features and patient outcomes based on the anaerobic genera or group. METHODS: Medical records of patients with anaerobic BSIs were used to conduct a single-center retrospective cohort study from January 2016 to December 2020 in Nagoya, Japan. Multivariate logistic regression analysis was performed to determine the independent risk factors for in-hospital mortality. RESULTS: Of the 215 patients with anaerobic BSIs, 31 had multiple anaerobic organisms in the blood culture, including 264 total episodes of anaerobic BSIs. Bacteroides spp. were isolated the most (n = 74), followed by gram-positive non-spore-forming bacilli (n = 57), Clostridium spp. (n = 52), gram-positive anaerobic cocci (GPAC) (n = 27), and gram-negative cocci (n = 7). The median patient age was 76 years; 56.7% were male. The most common focal infection site was intra-abdominal (36.7%). The in-hospital mortality caused by anaerobic BSIs was 21.3%, and was highest with Clostridium spp. (36.5%) and lowest with GPAC (3.7%). Age, solid tumors, and Clostridium spp. were independent risk factors for in-hospital mortality. CONCLUSIONS: We identified current anaerobic BSI trends using MALDI-TOF MS and reported that mortality in patients with anaerobic BSIs patients was highest with Clostridium spp. infections.

An investigation of the environmental niches of blown pack spoilage causing Clostridium estertheticum and Clostridium gasigenes on New Zealand beef and sheep farms.

The transfer of blown pack spoilage causing Clostridium spores from the farm to the meat plant is of growing concern to the meat industry. This study investigated the environmental niches of these Clostridium spp., specifically Clostridium estertheticum and Clostridium gasigenes in the beef and sheep farm environments in New Zealand. Faecal, soil, grass, drinking water, puddle water and feed (fodder beet, hay, bailage and silage, where available) samples were collected on five beef and sheep farms during Winter and Spring in 2018, in North and South Island, respectively. Beef and sheep farm samples were tested for C. estertheticum and C. gasigenes using enrichment plus PCR, qPCR and direct plating. C. estertheticum was detected in bovine faecal (4%), soil (2-18%) and grass (0-12%) samples at concentration of up to 2.0 log10 cfu/g. C. gasigenes were found in 18-46% of faecal, 16-82% of soil, 12-44% of grass, 0-44.4% of drinking water and 0-58.3% of puddle water samples tested and the direct counts ranged from 2.4 log10 cfu/ml in puddle water to 3.4 log10 cfu/g in soil. C. estertheticum were detected by qPCR in sheep farms in ovine feces (2.3%), soil (2.3%) and fodder beet (10%). All other sample types (grass, drinking water, puddle water, baleage, hay, silage and fodder beet) were negative using direct and enrichment plus PCR methods. In contrast C. gasigenes was detected in of faecal (22.7-38.6%), soil (22.7-84.1%), grass (17.5-34.1%) drinking water (35.7-78.6%), puddle water (33.3-40%), hay baleage (57%), silage (2%) and fodder beet (10%) at concentrations of up to 3.7 log10 cfu/g/ml. It was concluded that C. estertheticum and C. gasigenes were common on beef and sheep farms with the latter having higher incidence and mean concentration.

Comparative genomics of Clostridium species associated with vacuum-packed meat spoilage.

Bacterial species belonging to the genus Clostridium have been recognized as causative agents of blown pack spoilage (BPS) in vacuum packed meat products. Whole-genome sequencing of six New Zealand psychrotolerant clostridia isolates derived from three meat production animal types and their environments was performed to examine their roles in BPS. Comparative genome analyses have provided insight into the genomic diversity and physiology of these bacteria and divides clostridia into two separate species clusters. BPS-associated clostridia encode a large and diverse spectrum of degradative carbohydrate-active enzymes (CAZymes) that enable them to utilize the intramuscular carbohydrate stores and facilitate sporulation. In total, 516 glycoside hydrolases (GHs), 93 carbohydrate esterases (CEs), 21 polysaccharide lyases (PLs), 434 glycosyl transferases (GTs) and 211 carbohydrate-binding protein modules (CBM) with predicted activities involved in the breakdown and transport of carbohydrates were identified. Clostridia genomes have different patterns of CAZyme families and vary greatly in the number of genes within each CAZy category, suggesting some level of functional redundancy. These results suggest that BPS-associated clostridia occupy similar environmental niches but apply different carbohydrate metabolism strategies to be able to co-exist and cause meat spoilage.

Stunted childhood growth is associated with decompartmentalization of the gastrointestinal tract and overgrowth of oropharyngeal taxa.

Linear growth delay (stunting) affects roughly 155 million children under the age of 5 years worldwide. Treatment has been limited by a lack of understanding of the underlying pathophysiological mechanisms. Stunting is most likely associated with changes in the microbial community of the small intestine, a compartment vital for digestion and nutrient absorption. Efforts to better understand the pathophysiology have been hampered by difficulty of access to small intestinal fluids. Here, we describe the microbial community found in the upper gastrointestinal tract of stunted children aged 2-5 y living in sub-Saharan Africa. We studied 46 duodenal and 57 gastric samples from stunted children, as well as 404 fecal samples from stunted and nonstunted children living in Bangui, Central African Republic, and in Antananarivo, Madagascar, using 16S Illumina Amplicon sequencing and semiquantitative culture methods. The vast majority of the stunted children showed small intestinal bacterial overgrowth dominated by bacteria that normally reside in the oropharyngeal cavity. There was an overrepresentation of oral bacteria in fecal samples of stunted children, opening the way for developing noninvasive diagnostic markers. In addition, Escherichia coli/Shigella sp. and Campylobacter sp. were found to be more prevalent in stunted children, while Clostridia, well-known butyrate producers, were reduced. Our data suggest that stunting is associated with a microbiome "decompartmentalization" of the gastrointestinal tract characterized by an increased presence of oropharyngeal bacteria from the stomach to the colon, hence challenging the current view of stunting arising solely as a consequence of small intestine overstimulation through recurrent infections by enteric pathogens.