Sex-Dependent Effects of Inhaled Nicotine on the Gut Microbiome.

INTRODUCTION: The impact of nicotine, the addictive component of both traditional cigarettes and e-cigarettes, on many physiological processes remains poorly understood. To date, there have been few investigations into the impact of nicotine on the gut microbiome, and these studies utilized oral administration rather than inhalation. This study aimed to establish if inhaled nicotine alters the gut microbiome and the effect of sex as a biological variable. METHODS: Female (n = 8 air; n = 10 nicotine) and male (n = 10 air; n = 10 nicotine) C57BL6/J mice were exposed to air (control) or nicotine vapor (12 hour/day) for 13 weeks. A fecal sample was collected from each mouse at the time of sacrifice, and the gut microbiome was analyzed by 16S rRNA gene sequencing. QIIME2, PICRUSt, and STAMP were used to detect gut bacterial differences and functional metabolic pathways. RESULTS: Sex-specific differences were observed in both alpha and beta diversities in the absence of nicotine. While nicotine alters microbial community structure in both male and female mice as revealed by the beta diversity metric, nicotine significantly reduced alpha diversity only in female mice. A total of 42 bacterial taxa from phylum to species were found to be significantly different among the treatment groups. Finally, analysis for functional genes revealed significant differences in twelve metabolic pathways in female mice and ten in male mice exposed to nicotine compared to air controls. CONCLUSIONS: Nicotine inhalation alters the gut microbiome and reduces bacterial diversity in a sex-specific manner, which may contribute to the overall adverse health impact of nicotine. IMPLICATIONS: The gut microbiota plays a fundamental role in the well-being of the host, and traditional cigarette smoking has been shown to affect the gut microbiome. The effects of nicotine alone, however, remain largely uncharacterized. Our study demonstrates that nicotine inhalation alters the gut microbiome in a sex-specific manner, which may contribute to the adverse health consequences of inhaled nicotine. This study points to the importance of more detailed investigations into the influence of inhaled nicotine on the gut microbiota.

Formation of Lutein, ß-Carotene and Astaxanthin in a Coelastrella sp. Isolate.

In this study, the effect of media composition, N/P ratio and cultivation strategy on the formation of carotenoids in a Coelastrella sp. isolate was investigated. A two-stage process utilizing different media in the vegetative stage, with subsequent re-suspension in medium without nitrate, was employed to enhance the formation of carotenoids. The optimal growth and carotenoid content (ß-carotene and lutein) in the vegetative phase were obtained by cultivation in M-8 and BG11 media. Use of a N/P ratio of 37.5 and low light intensity of 40 µmol m-2 s-1 (control conditions) led to optimal biomass production of up to 1.31 g L-1. Low concentrations of astaxanthin (maximum of 0.31 wt. %) were accumulated under stress conditions (nitrogen-deficient medium containing 1.5 % of NaCl and light intensity of 500 µmol m-2 s-1), while ß-carotene and lutein (combined maximum of 2.12 wt. %) were produced under non-stress conditions. Lipid analysis revealed that palmitic (C16:0) and oleic (C18:1) constituted the main algal fatty acid chains (50.2 ± 2.1% of the total fatty acids), while esterifiable lipids constituted 17.2 ± 0.5% of the biomass by weight. These results suggest that Coelastrella sp. could also be a promising feedstock for biodiesel production.

Characterization of hospital airborne SARS-CoV-2.

BACKGROUND: The mechanism for spread of SARS-CoV-2 has been attributed to large particles produced by coughing and sneezing. There is controversy whether smaller airborne particles may transport SARS-CoV-2. Smaller particles, particularly fine particulate matter (≤ 2.5 µm in diameter), can remain airborne for longer periods than larger particles and after inhalation will penetrate deeply into the lungs. Little is known about the size distribution and location of airborne SARS-CoV-2 RNA. METHODS: As a measure of hospital-related exposure, air samples of three particle sizes (> 10.0 µm, 10.0-2.5 µm, and ≤ 2.5 µm) were collected in a Boston, Massachusetts (USA) hospital from April to May 2020 (N = 90 size-fractionated samples). Locations included outside negative-pressure COVID-19 wards, a hospital ward not directly involved in COVID-19 patient care, and the emergency department. RESULTS: SARS-CoV-2 RNA was present in 9% of samples and in all size fractions at concentrations of 5 to 51 copies m-3. Locations outside COVID-19 wards had the fewest positive samples. A non-COVID-19 ward had the highest number of positive samples, likely reflecting staff congregation. The probability of a positive sample was positively associated (r = 0.95, p < 0.01) with the number of COVID-19 patients in the hospital. The number of COVID-19 patients in the hospital was positively associated (r = 0.99, p < 0.01) with the number of new daily cases in Massachusetts. CONCLUSIONS: More frequent detection of positive samples in non-COVID-19 than COVID-19 hospital areas indicates effectiveness of COVID-ward hospital controls in controlling air concentrations and suggests the potential for disease spread in areas without the strictest precautions. The positive associations regarding the probability of a positive sample, COVID-19 cases in the hospital, and cases in Massachusetts suggests that hospital air sample positivity was related to community burden. SARS-CoV-2 RNA with fine particulate matter supports the possibility of airborne transmission over distances greater than six feet. The findings support guidelines that limit exposure to airborne particles including fine particles capable of longer distance transport and greater lung penetration.

Analysis of the microbial diversity in the fecal material of the critically endangered African wild dog, Lycaon pictus.

The African wild dog (AWD) (Lycaon pictus) is a critically endangered species. These animals are hypercarnivores, hunting mostly medium-sized antelope. In this study, using bacterial tag-encoded FLX-Titanium amplicon pyrosequencing (bTEFAP®), the microbiota in the fecal material of AWDs living in the Great Plains Zoo & Delbridge Museum of Natural History was investigated. In both samples, the most predominant bacterial phylum was the Firmicutes with members of the genus Blautia spp. being the most dominant bacteria.

Clostridium chrysemydis sp. nov., isolated from the faecal material of a painted turtle.

A strict anaerobic, Gram-stain-positive rod-shaped bacterium, designated PTT, was isolated from the faecal material of a painted turtle (Chrysemys picta). Based on a comparative 16S rRNA gene sequence analysis, the isolate was assigned to Clostridium sensu stricto with the highest sequence similarities to Clostridium moniliforme (97.4 %), Clostridium sardiniense (97.2 %) and the misclassified organism Eubacterium multiforme (97.1 %). The predominant cellular fatty acids of strain PTT were C14 : 0, C16 : 0 and an unidentified product with an equivalent chain length of 14.969. The G+C content determined from the genome was 28.8 mol%. The fermentation end products from glucose were acetate and butyrate with no alcohols detected and trace amounts of CO2 and H2 also detected; no respiratory quinones were detected. Based on biochemical, phylogenetic, genotypic and chemotaxonomic criteria, the isolate represents a novel species of the genus Clostridium for which the name Clostridium chrysemydis sp. nov. is proposed. The type strain is strain PTT (=CCUG 74180T=ATCC TSD-219T).

Characterization of the Biodiesel Degrading Acinetobacter oleivorans Strain PT8 Isolated from the Fecal Material of a Painted Turtle (Chrysemys picta).

Acinetobacter species are gram-negative, non-fermenting bacteria with coccobacilli morphology. The bacteria are found ubiquitously and have the ability to occupy niches which include environmental sites, animals, and humans. The original purpose of this study was to determine if painted turtles (Chrysemys picta) living in the wild in Western Wisconsin were colonized with carbapenem-resistant bacteria. Fecal samples from ten turtles were examined for carbapenem-resistant bacteria. None of the isolates were found to be carbapenem resistant by antimicrobial susceptibility testing. However, all the isolates were resistant to other ß-lactams and chloramphenicol classes of antimicrobials. One isolate, Acinetobacter oleivorans strain PT8, was selected for additional characterization, including whole-genome sequencing (WGS). Strain PT8 is capable of degrading biodiesel, forming biofilms, and has a putative type 6 gene cluster. Finally, the taxonomic position of the available whole-genome sequences of 25 A. oleivorans genomes from purified isolates was determined.

Isolation and characterisation of carbapenem-resistant Xanthomonas citri pv. mangiferaeindicae-like strain gir from the faecal material of giraffes.

The purpose of this study was to determine if giraffes (Giraffa camelopardalis) living in captivity at the Jacksonville Zoo and Gardens, Jacksonville, FL were colonised with carbapenem-resistant bacteria and, if found, to identify underlying genetic mechanisms contributing to a carbapenem-resistant phenotype. Faecal samples from seven giraffes were examined for carbapenem-resistant bacteria. Only one isolate (a Xanthomondaceae) was found to be carbapenem-resistant by antibiotic susceptibility testing. This isolate was selected for additional characterization, including whole genome sequencing (WGS). Based on average nucleotide identity, the bacterium was identified as Xanthomonas citri pv. mangiferaeindicae-like strain gir. Phenotypic carbapenemase tests and PCR for the most common carbapenemase genes produced negative results, suggesting that carbapenem resistance was mediated by another mechanism. Resistance gene profile analysis of WGS results confirmed these results. Among identified resistance genes, a chromosomal class A beta-lactamase with 71% identity to the penP beta-lactamase gene from Xanthomonas citri ssp. citri was identified, which could contribute to a carbapenem-resistant phenotype.

Analysis of the Microbial Diversity in the Fecal Material of Giraffes.

Using bacterial and fungal tag-encoded FLX-Titanium amplicon pyrosequencing, the microbiota of the fecal material of seven giraffes living in captivity at the Jacksonville Zoo and Gardens, Jacksonville, FL was investigated. In all samples, the most predominant bacterial phylum was the Firmicutes followed by Bacteroidetes. The most predominant fungi were members of the phylum Ascomycota followed by Neocallimastigomycota in five of seven samples. The reverse was true in the other two samples.

Enterococcus crotali sp. nov., isolated from faecal material of a timber rattlesnake.

A facultatively anaerobic, Gram-stain-positive bacterium, designated ETRF1T, was found in faecal material of a timber rattlesnake (Crotalus horridus). Based on a comparative 16S rRNA gene sequence analysis, the isolate was assigned to the genus Enterococcus. The 16S rRNA gene sequence of strain ETRF1T showed >97 % similarity to that of the type strains of Enterococcus rotai, E. caccae, E. silesiacus, E haemoperoxidus, E. ureasiticus, E. moraviensis, E. plantarum, E. quebecensis, E. ureilyticus, E. termitis, E. rivorum and E. faecalis. The organism could be distinguished from these 12 phylogenetically related enterococci using conventional biochemical testing, the Rapid ID32 Strep system, comparative pheS and rpoA gene sequence analysis, and comparative whole genome sequence analysis. The estimated in silico DNA-DNA hybridization values were <70 %, and average nucleotide identity values were <96 %, when compared to these 12 species, further validating that ETRF1T represents a unique species within the genus Enterococcus. On the basis of these analyses, strain ETRF1T (=CCUG 65857T=LMG 28312T) is proposed as the type strain of a novel species, Enterococcus crotali sp. nov.

Comprehensive Molecular Characterization of Bacterial Communities in Feces of Pet Birds Using 16S Marker Sequencing.

Birds and other animals live and evolve in close contact with millions of microorganisms (microbiota). While the avian microbiota has been well characterized in domestic poultry, the microbiota of other bird species has been less investigated. The aim of this study was to describe the fecal bacterial communities of pet birds. Pooled fecal samples from 22 flocks representing over 150 individual birds of three different species (Melopsittacus undulatus or budgerigars, Nymphicus hollandicus or cockatiels, and Serinus canaria or domestic canaries) were used for analysis using the 16S rRNA gene sequencing in the MiSeq platform (Illumina). Firmicutes was the most abundant phylum (median 88.4 %; range 12.9-98.4 %) followed by other low-abundant phyla such as Proteobacteria (median 2.3 %; 0.1-85.3 %) and Actinobacteria (median 1.7 %; 0-18.3 %). Lactobacillaceae (mostly Lactobacillus spp.) was the most abundant family (median 78.1 %; 1.4-97.5 %), especially in budgerigars and canaries, and it deserves attention because of the ascribed beneficial properties of lactic acid bacteria. Importantly, feces from birds contain intestinal, urinary, and reproductive-associated microbiota thus posing a serious problem to study one anatomical region at a time. Other groups of interest include the family Clostridiaceae that showed very low abundance (overall median <0.1 %) with the exception of two samples from cockatiels (14 and 45.9 %) and one sample from budgerigars (19.9 %). Analysis of UniFrac metrics showed that overall, the microbial communities from the 22 flocks tended to cluster together for each bird species, meaning each species shed distinctive bacterial communities in feces. This descriptive analysis provides insight into the fecal microbiota of pet birds.

Pyrosequencing based assessment of bacterial diversity in Turkish Rhipicephalus annulatus and Dermacentor marginatus ticks (Acari: Ixodidae).

Ticks continue to be a threat to human and animal health in Turkey, as they are considered important vectors of human and animal diseases. The objectives of this investigation are to characterize the microbial communities of two tick species, Rhipicephalus annulatus and Dermacenter marginatus, analyze patterns of co-occurrence among microbial taxa, identify and compare pathogens contributing human diseases, and determine whether avirulent symbionts could exclude human pathogens from tick communities. Furthermore, this study explores a microbiome of the R. annulatus and D. marginatus via the bacterial 16S tag-encoded FLX-titanium amplicon pyrosequencing (bTEFAP) technique to describe their bacterial diversity. Pyrosequencing was performed on adult males and females isolated from humans from two high-risk Turkish provinces, Sivas and Amasya, during tick outbreaks in 2009. A total of 36,253 sequences were utilized for analyses of the 8 tick samples. Several pathogenic genera such as Francisella, Coxiella, Rickettsia, and Shigella were detected in the ticks tested. The most distinguishable difference between the two species of ticks was the lack of known human pathogen Rickettsia in R. annulatus and in samples 9 and 10 of D. marginatus. These samples had higher relative abundance of Flavobacterium sp., Curvibacter sp., Acidovorax sp., and Bacteroidaceae genera mostly representing symbionts which form a large component of normal tick microbiota. The outcome of this study is consistent with the predictions of the community ecological theory that diversity-rich bacteriomes are more resistant to bacterial invasion (and consequent pathogen dissemination) than diversity-deprived ones.

Assessment of bacterial diversity in Hyalomma aegyptium, H. marginatum and H. excavatum ticks through tag-encoded pyrosequencing.

Ticks are among the most significant human-biting ectoparasites and they play a major role in transmission of many pathogenic agents to humans. In the present study, three species of Hyalomma ticks, Hyalomma aegyptium, H. marginatum and H. excavatum, were examined for the presence of zoonotic bacteria, both male and female ticks alike. Examination of microbial diversity with tag-encoded pyrosequencing indicates that H. marginatum and H. excavatum were more diversity rich than H. aegyptium. Although numerous pathogenic and non-pathogenic bacterial genera were detected, including Acidovorax, Bacillus, Bacteroides, Bdellovibrio, Clostridium, Curvibacter, Escherichia, Flavobacterium, Limnohabitans, Paenibacillus, Ralstonia, Sarcina, Sediminibacterium, Segetibacter Stenotrophomonas and Variovorax, the predominant zoonotic bacteria represented in these ticks were genera Borrelia, Francisella, and Rickettsia. To the authors' knowledge, this work represents the first detection of Yersinia enterocolitica in the tick H. excavatum, raising questions regarding the vector competency of this tick, as well as associations of different disease representations perhaps through previously unforeseen routes of pathogen introduction. Likewise, similar questions are related to the presence of Legionella pneumophila in one H. excavatum sample.

The predominant site of bacterial translocation across the intestinal mucosal barrier occurs at the advancing disease margin in Crohn's disease.

Crohn's disease is characterized by increased permeability of the intestinal mucosal barriers and an abnormal or dysregulated immune response to specific and/or commensal bacteria arising from the intestinal lumen. To determine the types of bacteria that are transgressing the mucosal barrier and colonizing the intestinal submucosal tissues, we performed 16S rRNA gene microbiota sequencing of the submucosal and mucosal tissues at the advancing disease margin in ileal Crohn's disease. Microbial populations were compared between mucosa and submucosa and non-inflammatory bowel disease (non-IBD) controls, as well as to microbial populations previously found at the centre of the disease lesion. There was no significant increase in bacteria within the submucosa of non-IBD controls at any taxonomic level when compared to the corresponding superjacent mucosa, indicating an effective mucosal barrier within the non-IBD population. In contrast, there was a statistically significant increase in 13 bacterial families and 16 bacterial genera within the submucosa at the advancing disease margin in Crohn's disease when compared to the superjacent mucosa. Major increases within the submucosa included bacteria of the Families Sphingomonadaceae, Alicyclobacillaceae, Methylobacteriaceae, Pseudomonadaceae and Prevotellaceae. Data suggest that the primary site of bacterial translocation across the mucosal barrier occurs at the margin between diseased and normal tissue, the advancing disease margin. The heterogeneity of the bacterial populations penetrating the mucosal barrier and colonizing the submucosal intestinal tissues and, therefore, contributing to the inflammatory processes, suggests that bacterial translocation is secondary to a primary event leading to a breakdown of the mucosal barrier.

Loss of n-6 fatty acid induced pediatric obesity protects against acute murine colitis.

Dietary influences may affect microbiome composition and host immune responses, thereby modulating propensity toward inflammatory bowel diseases (IBDs): Crohn disease (CD) and ulcerative colitis (UC). Dietary n-6 fatty acids have been associated with UC in prospective studies. However, the critical developmental period when (n-6) consumption may induce UC is not known. We examined the effects of transiently increased n-6 consumption during pediatric development on subsequent dextran-sulfate-sodium (DSS)-induced acute murine colitis. The animals transiently became obese then rapidly lost this phenotype. Interestingly, mice were protected against DSS colitis 40 days after n-6 consumption. The transient high n-6-induced protection against colitis was fat type- and dietary reversal-dependent and could be transferred to germ-free mice by fecal microbiota transplantation. We also detected decreased numbers of chemokine receptor (Cxcr)5(+) CD4(+) T cells in the mesenteric lymph nodes (MLNs) of transiently n-6-fed mice. Further experiments revealed that anti-chemokine ligand (Cxcl)13 (the ligand of Cxcr5) antibody treatment decreased DSS colitis severity, implicating the importance of the Cxcr5-Cxcl13 pathway in mammalian colitis. Consecutively, we found elevated CXCL13 concentrations (CD: 1.8-fold, P = 0.0077; UC: 1.9-fold, P = 0.056) in the serum of untreated pediatric IBD patients. The human serologic observations supported the translational relevance of our findings.

Analysis of the microbial diversity in faecal material of the endangered blue whale, Balaenoptera musculus.

Using bacterial and fungal tag-encoded FLX-Titanium amplicon pyrosequencing, the microbiota of the faecal material of two blue whales living in the wild off the coast of California was investigated. In both samples the most predominant bacterial phylum was the Firmicutes with Clostridium spp. being the most dominant bacteria. The most predominant fungi were members of the phylum Ascomycota with Metschnikowia spp. being the most dominant. In this study, we also preliminarily characterised the culturable anaerobic bacteria from the faecal material, using traditional culture and 16S rRNA gene sequencing approaches. In total, three bacterial species belonging to the phylum Firmicutes were identified.

Neither vaginal nor buccal administration of 800 µg misoprostol alters mucosal and systemic immune activation or the cervicovaginal microbiome: a pilot study.

OBJECTIVES: The aim of the study was to assess the extent to which misoprostol alters mucosal or systemic immune responses following either buccal or vaginal administration. METHODS: This was a prospective, crossover pilot study of 15 healthy, reproductive-age women. Women first received 800 µg misoprostol either via buccal or vaginal administration and were crossed over 1 month later to receive the drug via the other route. Cervicovaginal lavage samples, cervical Cytobrush samples, cervicovaginal swabs, urine and blood were obtained immediately prior to drug administration and the following day. Parameters assessed included urine and cervicovaginal misoprostol levels, whole blood cytokine responses (by ELISA) to immune stimulation with lipopolysaccharide, peripheral blood and cervical lymphocyte phenotyping by flow cytometry, cervicovaginal antimicrobial peptide measurement by ELISA and vaginal microbial ecology assessment by 16S rRNA sequencing. RESULTS: Neither buccal nor vaginal misoprostol significantly altered local or systemic immune and microbiological parameters. CONCLUSION: In this pilot study, we did not observe significant alteration of mucosal or systemic immunology or vaginal microbial ecology 1 day after drug administration following either the buccal or vaginal route.

Inability of polymerase chain reaction, pyrosequencing, and culture of infected and uninfected site skin biopsy specimens to identify the cause of cellulitis.

BACKGROUND: The cause of cellulitis is unclear. Streptococcus pyogenes, and to a lesser extent, Staphylococcus aureus, are presumed pathogens. METHODS: We conducted a study of adults with acute cellulitis without drainage presenting to a US emergency department research network. Skin biopsy specimens were taken from the infected site and a comparable uninfected site on the opposite side of the body. Microbiology was evaluated using quantitative polymerase chain reaction (PCR), pyrosequencing, and standard culture techniques. To determine the cause, the prevalence and quantity of bacterial species at the infected and uninfected sites were compared. RESULTS: Among 50 subjects with biopsy specimens from infected and uninfected sites, culture rarely identified a bacterium. Among 49 subjects with paired specimens from infected and uninfected sites tested with PCR, methicillin-susceptible S. aureus was identified in 20 (41%) and 17 (34%), respectively. Pyrosequencing identified abundant atypical bacteria in addition to streptococci and staphylococci. Among 49 subjects with paired specimens tested by pyrosequencing, S. aureus was identified from 11 (22%) and 15 (31%) and streptococci from 15 (31%) and 20 (41%) of the specimens, respectively. Methicillin-resistant S. aureus was not found by culture or PCR, and S. pyogenes was not identified by any technique. CONCLUSIONS: The bacterial cause of cellulitis cannot be determined by comparing the prevalence and quantity of pathogens from infected and uninfected skin biopsy specimens using current molecular techniques. Methicillin-susceptible S. aureus was detected but not methicillin-resistant S. aureus or S. pyogenes from cellulitis tissue specimens. For now, optimal treatment will need to be guided by clinical trials. Noninfectious causes should also be explored.

Modulation of the faecal microbiome of healthy adult dogs by inclusion of potato fibre in the diet.

Inclusion of fermentable fibres in the diet can have an impact on the hindgut microbiome and provide numerous health benefits to the host. Potato fibre (PF), a co-product of potato starch isolation, has a favourable chemical composition of pectins, resistant and digestible starch, cellulose, and hemicelluloses. The objective of the present study was to evaluate the effect of increasing dietary PF concentrations on the faecal microbiome of healthy adult dogs. Fresh faecal samples were collected from ten female dogs with hound bloodlines (6·13 (SEM 0·17) years; 22·0 (SEM 2·1) kg) fed five test diets containing graded concentrations of PF (0, 1·5, 3, 4·5 or 6% as-fed; Roquette Frères) in a replicated 5 × 5 Latin square design. Extraction of DNA was followed by amplification of the V4-V6 variable region of the 16S rRNA gene using barcoded primers. Sequences were classified into taxonomic levels using Basic Local Alignment Search Tool (BLASTn) against a curated GreenGenes database. Inclusion of PF increased (P< 0·05) the faecal proportions of Firmicutes, while those of Fusobacteria decreased (P< 0·05). Similar shifts were observed at the genus level and were confirmed by quantitative PCR (qPCR) analysis. With increasing concentrations of PF, faecal proportions of Faecalibacterium increased (P< 0·05). Post hoc Pearson's correlation analysis showed positive (P< 0·05) correlations with Bifidobacterium spp. and butyrate production and Lactobacillus spp. concentrations. Overall, increases in the proportion of Faecalibacterium (not Lactobacillus/Bifidobacterium, as confirmed by qPCR analysis) and faecal SCFA concentrations with increasing dietary PF concentrations suggest that PF is a possible prebiotic fibre.

Metagenomic analysis of the gut microbiota of the Timber Rattlesnake, Crotalus horridus.

Snakes are capable of surviving long periods without food. In this study we characterized the microbiota of a Timber Rattlesnake (Crotalus horridus), devoid of digesta, living in the wild. Pyrosequencing-based metagenomics were used to analyze phylogenetic and metabolic profiles with the aid of the MG-RAST server. Pyrosequencing of samples taken from the stomach, small intestine and colon yielded 691696, 957756 and 700419 high quality sequence reads. Taxonomic analysis of metagenomic reads indicated Eukarya was the most predominant domain, followed by bacteria and then viruses, for all three tissues. The most predominant phylum in the domain Bacteria was Proteobacteria for the tissues examined. Functional classifications by the subsystem database showed cluster-based subsystems were most predominant (10-15 %). Almost equally predominant (10-13 %) was carbohydrate metabolism. To identify bacteria in the colon at a finer taxonomic resolution, a 16S rRNA gene clone library was created. Proteobacteria was again found to be the most predominant phylum. The present study provides a baseline for understanding the microbial ecology of snakes living in the wild.

Multiple Opportunistic Pathogens, but Not Pre-existing Inflammation, May Be Associated with Necrotizing Enterocolitis.

BACKGROUND: Necrotizing enterocolitis (NEC) leads to significant morbidity and mortality in the neonatal intensive care unit. Although current evidence would suggest that bacteria contribute to the pathogenesis of NEC, no single bacterium has yet been identified. AIMS: The aims of this study were to investigate fecal S100A12 concentrations and the intestinal bacterial community in premature infants (24-32 weeks) and investigate any associations between the microbiota and the development of NEC. METHODS: Meconium and feces were collected from premature newborn infants (between 24 and 32 weeks gestation) over the first 4 weeks of life. Fecal S100A12 concentrations were assayed by immunoassay, and samples were subject to 16S rDNA analysis using next-generation sequencing techniques. RESULTS: Fecal samples were collected from four infants that developed NEC and 18 control infants. Prior to developing NEC, fecal S100A12 concentrations were not elevated; however, following NEC diagnosis, concentrations were highly elevated. The fecal bacterial communities of infants with NEC did not differ significantly from control infants. However, potentially pathogenic bacteria were detected in significantly more infants with NEC than in controls (p = 0.0007). CONCLUSION: At birth, fecal S100A12 concentrations were not elevated in premature infants subsequently developing NEC in this cohort. Following NEC diagnosis, S100A12 concentrations were highly elevated, suggesting that this potentially could act as a marker of disease progression. Higher detection rates of potentially pathogenic bacteria in NEC infants suggest that a range of potentially pathogenic bacteria may collectively contribute to NEC pathogenesis.