Dual Colonization Research Articles

Aedes albopictus saliva contains a richer microbial community than the midgut

BackgroundPast findings demonstrate that arthropods can egest midgut microbiota into the host skin leading to dual colonization of the vertebrate host with pathogens and saliva microbiome. A knowledge gap exists on how the saliva microbiome interacts with the pathogen in the saliva. To fill this gap, we need to first define the microbial composition of mosquito saliva.MethodsThe current study aimed at analyzing and comparing the microbial profile of Aedes albopictus saliva and midgut as well as assessing the impact of Zika virus (ZIKV) infection on the midgut and saliva microbial composition. Colony-reared Ae. albopictus strains were either exposed to ZIKV infectious or noninfectious bloodmeal. At 14 ays postinfection, the 16S V3–V4 hypervariable rRNA region was amplified from midgut and saliva samples and sequenced on an Illumina MiSeq platform. The relative abundance and diversity of midgut and saliva microbial taxa were assessed.ResultsWe observed a richer microbial community in the saliva compared with the midgut, yet some of the microbial taxa were common in the midgut and saliva. ZIKV infection did not impact the microbial diversity of midgut or saliva. Further, we identified Elizabethkingia spp. in the Ae. albopictus saliva.ConclusionsThis study provides insights into the microbial community of the Ae. albopictus saliva as well as the influence of ZIKV infection on the microbial composition of its midgut and saliva. The identification of Elizabethkingia spp., an emerging pathogen of global health significance, in Ae. albopictus saliva is of medical importance. Future studies to assess the interactions between Ae. albopictus saliva microbiome and ZIKV could lead to novel strategies for developing transmission barrier tools.Graphical

VARIOUS ADHERENT-INVASIVE E. COLI (AIEC) AND NON-AIEC STRAINS ISOLATED FROM CROHN’S DISEASE PATIENTS GROW DIFFERENTLY WITH RUMINOCOCCUS GNAVUS PRE-DIGESTED MUCUS AND R. GNAVUS-RELEASED PRE-DIGESTED ILEAL AND COLONIC MUCUS MONOSACCHARIDES

Abstract BACKGROUND Mucus-digesting Ruminococcus gnavus (R. gnavus), adherent-invasive E. coli (AIEC), and hydrogen sulfide (H2S) are enriched in active Crohn’s disease (CD) patients compared to healthy subjects. Dual colonization of R. gnavus and E. coli LF82 in ex-germ-free mice enhanced distal colitis and H2S production in cecal contents. R. gnavus pre-digestion of mucus enhanced the ileal CD isolate AIEC LF82 growth and H2S production in vitro. H2S enhanced LF82 adhesion and invasion both in vitro and in vivo along with related LF82 adhesion gene expression and Caco-2 cell expression of CEACAM6, a receptor for AIEC ligand FimH. Interactions between other CD-derived AIEC/non-AIEC and R. gnavus are unknown. HYPOTHESIS Different AIEC and non-AIEC may grow and produce H2S differently using mucus digested by R. gnavus, which releases mucus-derived monosaccharides and sulfur substrates. METHODS We studied CD-derived clinical isolates of AIEC 541-15 (phylotype A), 541-1 (B1), LF82 and NRG857c (B2) and non-AIEC T75 (A) and lab strain K12 (A). M9 minimal media was supplemented with porcine gastric mucin (PGM), ileal (MIM) and colonic (MCoM) mucus isolated from germ-free mice. We measured growth kinetics and H2S production by these AIEC and non-AIEC following culture with sterile supernatants of each mucin/mucus media precultured with or without R. gnavus, monosaccharides obtained by R. gnavus digestion of mucus, and several sulfur substrates in the gut added to M9 minimal media. RESULTS AIEC, especially LF82 (B2), grew better with ileal mucus aerobically and, to a lesser extent, anaerobically than non-AIEC strains, with even greater AIEC growth with R. gnavus pre-digested mucus (Fig.1). AIEC produced more H2S with R. gnavus-precultured mucus than with mucus alone. R. gnavus digestion of PGM released mucus monosaccharides (Fig.2A). AIEC strains grew differently with each monosaccharide constituent of R. gnavus pre-digested PGM. AIEC grew better than non-AIEC with each monosaccharide in aerobic conditions, but AIEC (B2) grew better than others in all monosaccharides in anaerobic conditions (Fig.2B). Amongst mucus-relevant sulfur substrates, L-cysteine was the only substrate to enhance E. coli H2S production by all AIEC and non-AIEC strains. All mucus-relevant sulfur substrates supported R. gnavus survival for 24 hrs, while H2S sustained R. gnavus for 48 hrs in minimum media. CONCLUSIONS AIEC grew better and produced more H2S with R. gnavus pre-digested mucus suggesting that co-existence of AIEC with R. gnavus mutually support each other and may explain why they are often observed together in active CD patients. In addition, enhanced AIEC growth with ileal vs. colonic mucus may explain why AIEC are frequently isolated from ileal CD patients. AIEC phylotype growth differences with mucus substrates may explain their persistence in the ileal mucosa. Figure 1 Figure 2

Seasonal Dynamics in Mycorrhizal Colonization and Fine Root Features of the White Poplar (Populus alba L.) in Natural Temperate Riverside Forests with Two Contrasting Soils

Fine roots are the most dynamic and physiologically active components of belowground tree organs. However, much remains unknown regarding the changes in fine root morphological characteristics during mycorrhizal colonization, especially in natural sites. The aim of this study was to analyze seasonal heterogeneity in fine roots and the mycorrhizal colonization of mature white poplar (Populus alba L.) trees under different soil conditions. Two floodplain forests were selected in Central Europe (Poland), which differed in soil moisture and structure. Fine roots were sampled during one growing season from the upper soil layer. Poplars were characterized by dual mycorrhizal colonization on one root system. It was, therefore, possible to investigate the contribution of two mycorrhizal types (arbuscular mycorrhiza—AM; and ectomycorrhiza—ECM) in response to different habitat conditions. The season was shown to be significant for all fine root features, as well as the degree of mycorrhizal colonization. Roots were better adapted to a drier habitat with a greater proportion of sand, mainly due to a reduction in the fine root diameter (FRD), while other root characteristics did not differ significantly. The degree of mycorrhizal colonization (RLC) and the proportion of arbuscular mycorrhizal structures (AM) were significantly and negatively correlated with the soil water content. A mutual competition between arbuscular mycorrhizas and ectomycorrhizas for poplar roots was also observed, particularly with respect to the season, site, and soil moisture. Changing environmental conditions (especially soil moisture) contribute not only to the morphological and functional changes of fine roots but also to changes in the proportion of arbuscular mycorrhiza and ectomycorrhiza. Understanding the mechanisms of adaptation of tree roots to changing environmental conditions is especially important in the context of climate change.

Fungal diversity and colonization in roots seed trees of Swietenia macrophylla King (Magnoliophyta: Meliaceae) in the tropical rainforest of Laguna Om, Quintana Roo, Mexico

Aim of study: (i) To investigate the diversity of arbuscular mycorrhizal fungi (AMF) associated with the roots of seed trees stands in a conserved and natural population of mahogany (Swietenia macrophylla), based on rDNA sequences; and (ii) to evaluate the dual colonization by AMF and dark septate fungi (DSF), showing the types of fungal colonization patterns in the dry season. Area of study: Tropical rainforest of Ejido Laguna Om, Quintana Roo, Mexico. Material and methods: We evaluated the AMF and DSF colonization in secondary root segments of ten adult trees of mahogany. We analysed the diversity of AMF in one composite sample of mahogany roots (three trees) using 18S rDNA gene with Illumina MiSeq platform. Main results: Through metabarcoding 14 virtual taxa belonging mainly to the genus Glomus and Diversispora were obtained, VTX00186 being the most abundant. The percentages of colonization for the different fungal structures were hyphae 80%, vesicles 18%, coils 2%, and arbuscules 0.5%; for DSF, 60% hyphae and 12% microsclerotia. The Paris-type colonization predominated with 61% in the roots. Research highlights: The knowledge of the AMF diversity present in natural mahogany forests will allow the selection of species for inoculation management seeking to enhance seedling survival and growth of this species.

Mid‐Pleistocene events influenced the current spatial structure of genetic diversity in Scots pine (Pinus sylvestris L.)

AbstractScots pine (Pinus sylvestris L.) is one of the most important tree species of the temperate and boreal zones in Eurasia. Its wide distribution range and current patterns of genetic variation have been influenced by Quaternary climatic oscillations and the demographic processes connected to them. In order to better understand the relationship between evolutionary history and demographic factors in a widespread species with a large genome, we used the single‐nucleotide polymorphism (SNP) array to genotype thousands of SNP markers across 62 natural populations (N = 686 trees) of Scots pine in Eurasia. This provides the largest range‐wide SNPs' genetic diversity assessment of Scots pine to date. Our findings show evidence of past admixture events between genetic clusters that were retained despite the potential for effective pollen‐mediated gene flow across the species' distribution range. We also examined the contemporary population structure of the species and analyzed the range‐wide genetic diversity patterns. Phylogenetic analyses and demographic modeling suggest that the observed divergence patterns between genetic lineages likely predate the last glaciation events. Two of the most distinctive groups are represented by trees from the eastern parts of Fennoscandia and Eastern Russia, which have remained separated since the mid‐Pleistocene. The patterns of genetic variation also confirm the dual colonization of Fennoscandia and the existence of an admixture zone in Central Europe that was formed during multiple waves of postglacial recolonization. This study provides insights into the genetic relationships of Scots pine populations from Europe and Asia and offers a more comprehensive understanding of the species' history.

In vitro efficacy of fungal endophytes and silver pyrazolate against Raffaelea lauricola, causal agent of laurel wilt of avocado

The South Florida avocado industry is being severely impacted by laurel wilt disease. Laurel wilt disease of avocado is caused by the fungal pathogen, Raffaelea lauricola (RL) and is vectored by ambrosia beetle, Xyleborus glabratus. Treatments options are limited, economically not sustainable, and require reapplication fungicides every couple of years. There is a crucial need for developing multiple modes of control using novel biological and chemical agents. The ambrosia beetle associated pathogenic fungi are known to outcompete other microorganisms by taking advantage of ethanol produced by the pathogen and the stressed tree. Endophytes, which reside inside the host plant tissue are part of the plant microbiome represent source of new potential biological control agents. In this study, three ethanol tolerant endophytic fungal species, isolated from avocado bark, were evaluated using in vitro dual culture assay and colonization tube (packed with bark/sapwood shaving) against RL. The endophytic isolates Tricoderma crissum, Tricoderma simmonsii, Lasiodiplodia theobromae were found to be highly capable of suppressing the mycelial colony growth of RL. The results suggest that combined abilities of ethanol tolerance and competitive colonization can provide useful criteria for identifying potential biocontrol agents. In vitro anti-RL activity of silver pyrazolate compound was assessed in both agar and liquid medium. Silver pyrazolate at levels of 30 and 45 ppm were found to be highly effective against RL. Further in planta research is needed to study the effects of endophytic fungal isolates and silver pyrazolate to assess their potential as additional tools for management of laurel wilt.

Palestinians Under Israeli Settler Colonialism and "Anglo-Centric" Colonization of Knowledge Production.

Calls for decolonizing knowledge production are increasing considerably. Yet the domination of knowledge production by English-speaking, neoliberal, Western countries continues, with understandings and assumptions often irrelevant and unimportant to southern countries, and can contain racialized portrayals of the people of the developing world. Palestinians under Israeli military rule have also become governed by neoliberal funding northern institutions that have commoditized research and education and control what should be researched and how. The dual colonization of Palestinians by Israel and the hegemony of neoliberal political-economy among a captive Palestinian population-reinforced by the Zionist lobby's ferociousness in punishing whoever dares to raise questions about Israel's wrongdoings-is silencing Palestinians and those supporting justice to Palestinians in ways perhaps not experienced by others who want their voices heard. Yet Palestinians continue to teach and conduct research and to struggle for freedom and justice on one hand and for liberation from donor dictates on what to research and how to research and write on the other. We continue to hope that international funders and publishers would take concrete steps to turn calls for the decolonization of knowledge production from lip service to actions so that all knowledges can contribute to debates and societal advancement worldwide.

Cover crops enhance resource availability for soil microorganisms in a pecan orchard

Currently, there are substantial knowledge gaps on the impacts of cover crops on soil resources in tree cropping systems, wherein they are typically planted in interrow alleys and maintained for multiple years. While cover crops uptake soil nutrients and water, they can also prevent soil water evaporative losses and return nutrients to soils via decomposition of plant residues and stimulation of microbial nutrient cycling. This field sampling study examined variances in soil conditions across 5- and 7-year-old, cover cropped pecan orchards. We collected soil beneath cover crops and beneath adjacent trees, where soil was kept bare, to evaluate impacts of cover on the soil biota, nutrients, carbon, and their dynamics across a production season. We employed routine soil chemical analyses, phospholipid fatty acid (PLFA) analysis, and high throughput sequencing of 16 S rRNA genes and ITS regions for soils collected at four time points. We revealed that the cover cropped alley soils contained higher relative abundances of microbes that use labile soil substrates in resource rich conditions than did the tree row soils. Soil chemical analyses provided additional evidence that the cover crops did not deplete soil nutrients and reduce soil moisture, but rather, enhanced soil nutrient and moisture contents during many of the sampling time points. Notably, cover crop plant species correlated with soil nutrients and plant beneficial microbes, which may warrant consideration when selecting cover crop species. The tree row and cover cropped alley soils had different proportions of plant-beneficial mycorrhizal fungi. The tree rows supported higher numbers of ectomycorrhizal (ECM) fungi and alleys had higher relative abundances of arbuscular mycorrhizal (AM) fungi, suggesting potential benefits for tree species like pecan, which support dual colonization by AM and ECM Fungi. Altogether, the cover crops enhanced soil carbon, nutrients, and microbial populations in a pecan orchard and these impacts were frequently larger in a 7-year-old versus 5-year-old orchard.

Association of nasopharyngeal viruses and pathogenic bacteria in children and their parents with and without HIV

BackgroundBacteria and respiratory viruses co-occur in the nasopharynx, and their interactions may impact pathogenesis of invasive disease. Associations of viruses and bacteria in the nasopharynx may be affected by HIV.MethodsWe conducted a nested case-control study from a larger cohort study of banked nasopharyngeal swabs from families with and without HIV in West Bengal India, to look at the association of viruses and bacteria in the nasopharynx of parents and children when they are asymptomatic. Quantitative polymerase chain reaction for 4 bacteria and 21 respiratory viruses was run on 92 random nasopharyngeal swabs from children--49 from children living with HIV (CLH) and 43 from HIV uninfected children (HUC)-- and 77 swabs from their parents (44 parents of CLH and 33 parents of HUC).ResultsBacteria was found in 67% of children, viruses in 45%, and both in 27% of child samples. Staphylococcus aureus (53%) was the most common bacteria, followed by Streptococcus pneumoniae (pneumococcus) (37%) in children and parents (53, 20%). Regardless of HIV status, viruses were detected in higher numbers (44%) in children than their parents (30%) (p = 0.049), particularly rhinovirus (p = 0.02). Human rhinovirus was the most frequently found virus in both CLH and HUC. Children with adenovirus were at six times increased risk of also having pneumococcus (Odds ratio OR 6, 95% CI 1.12–31.9) regardless of HIV status. In addition, the presence of rhinovirus in children was associated with increased pneumococcal density (Regression coeff 4.5, 1.14–7.9). In CLH the presence of rhinovirus increased the risk of pneumococcal colonization by nearly sixteen times (OR 15.6, 1.66–146.4), and, pneumococcus and S. aureus dual colonization by nearly nine times (OR 8.7).ConclusionsChildren more frequently carried viruses regardless of HIV status. In CLH the presence of rhinovirus, the most frequently detected virus, significantly increased co-colonization with pneumococcus and S. aureus.

Phylogenomic analyses reveal a Gondwanan origin and repeated out of India colonizations into Asia by tarantulas (Araneae: Theraphosidae).

The study of biogeography seeks taxa that share a key set of characteristics, such as timescale of diversification, dispersal ability, and ecological lability. Tarantulas are ideal organisms for studying evolution over continental-scale biogeography given their time period of diversification, their mostly long-lived sedentary lives, low dispersal rate, and their nevertheless wide circumtropical distribution. In tandem with a time-calibrated transcriptome-based phylogeny generated by PhyloBayes, we estimate the ancestral ranges of ancient tarantulas using two methods, DEC+j and BBM, in the context of their evolution. We recover two ecologically distinct tarantula lineages that evolved on the Indian Plate before it collided with Asia, emphasizing the evolutionary significance of the region, and show that both lineages diversified across Asia at different times. The most ancestral tarantulas emerge on the Americas and Africa 120 Ma–105.5 Ma. We provide support for a dual colonization of Asia by two different tarantula lineages that occur at least 20 million years apart, as well as a Gondwanan origin for the group. We determine that their current distributions are attributable to a combination of Gondwanan vicariance, continental rafting, and geographic radiation. We also discuss emergent patterns in tarantula habitat preferences through time.

Arbuscular Mycorrhizal and Dark Septate Endophyte Fungal Associations in Two Dominant Ginger Species of Northeast India

Studies on the prevalence of arbuscular mycorrhizal fungi (AMF) and dark septate endophytic fungi (DSEF) are limited for rhizomatous crops in subtropical ecosystems compared to other terrestrial habitats. Hence, the authors assessed the incidence of AMF and DSEF in roots and diversity of AMF in the rhizosphere of Zingiber montanum and Z. officinale collected from shifting cultivation fields of Manipur, Northeast (NE) India. Both the gingers had dual colonization of AMF and DSEF structures in different cortical cells of the same examined root segments and revealed the Intermediate type of AM morphology. Such endomycorrhizal symbiotic association is being reported for the first time in Z. montanum. Distribution of different AMF and DSEF structures varied significantly across the two ginger species. The total root length colonization with AMF and DSEF was highest in Z. montanum. The maximum spore population of AMF was recorded in Z. officinale soil, whereas the AMF species richness was highest in Z. montanum rhizosphere. Altogether, 13 spore morphotypes of AMF corresponding to eight genera, i.e., Acaulospora, Claroideoglomus, Funneliformis, Glomus, Rhizophagus, Sclerocystis, Scutellospora and Septoglomus were isolated from the field and trap culture soils of both ginger species. Significant positive correlations were recorded between some soil properties and root-colonizing variables of AMF and DSEF. Thus, the occurrence of native AMF and DSEF associations in two important indigenous gingers cultivated in the Jhum fields of hilly terrains reveals the possibility of utilizing them in the future for sustainable agriculture.

Genetic basis of amphibian larval development along a latitudinal gradient: Gene diversity, selection and links with phenotypic variation in transcription factor C/EBP-1.

Ectotherm development rates often show adaptive divergence along climatic gradients, but the genetic basis for this variation is rarely studied. Here, we investigated the genetic basis for phenotypic variation in larval development in the moor frog Rana arvalis from five regions along a latitudinal gradient from Germany to northern Sweden. We focused on the C/EBP-1 gene, a transcription factor associated with larval development time. Allele frequencies at C/EBP-1 varied strongly among geographical regions. Overall, the distribution of alleles along the gradient was in concordance with the dual post-glacial colonization routes into Scandinavia, with a large number of alleles exclusively present along the southern colonization route. Only three of 38 alleles were shared between the routes. Analysis of contemporary selection on C/EBP-1 showed divergent selection among the regions, probably reflecting adaptation to the local environmental conditions, although this was especially strong between southern and northern regions coinciding also with lineages from different colonization routes. Overall, the C/EBP-1 gene has historically been under purifying selection, but two specific amino acid positions showed significant signals of positive selection. These positions showed divergence between southern and northern regions, and we suggest that they are functionally involved in the climatic adaptation of larval development. Using phenotypic data from a common garden experiment, we found evidence for specific C/EBP-1 alleles being correlated with larval development time, suggesting a functional role in adaptation of larval development to large-scale climatic variation.

Arbuscular mycorrhiza and dark septate endophyte fungal associations of Oryza sativa L. under field condition: colonization features and their occurrence

The present study was aimed to study monthly colonization of arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal associations in rice. The presence of mycorrhizal structures in the roots confirms the colonization by AM fungi. The pattern of hyphae and arbuscules denotes Arum type of AM fungal morphology. The presence of dark coloured septate hyphae running frequently on the epidermal layer and in root cortex and the occurrence of microsclerotia marks the colonization by DSE fungi. The co-occurrence of both AM and DSE fungi ensure dual colonization by two distinct fungal groups. There was significant increase in arbuscules, vesicles and hyphal percentages from first to third month in both the samples collected from two sites. In the third month, AM colonization significantly higher in both the sites. DSE colonization percentages do not differ significantly in first to third month. A total of nine AM fungal species were recovered from two sites. This study is an effort to make aware the local farmers about the usefulness of these native AM mycobiota which can be a preferable choice over chemical fertilizers leading to ecofriendly organic farming.

MP15-01 A COMMENSAL BACTERIAL STRAIN PREVENTS AND EFFECTIVELY AMELIORATES CHRONIC PELVIC PAIN

You have accessJournal of UrologyInfections/Inflammation/Cystic Disease of the Genitourinary Tract: Prostate & Genitalia I1 Apr 2018MP15-01 A COMMENSAL BACTERIAL STRAIN PREVENTS AND EFFECTIVELY AMELIORATES CHRONIC PELVIC PAIN Stephen Murphy, Anthony Schaeffer, and Praveen Thumbikat Stephen MurphyStephen Murphy More articles by this author , Anthony SchaefferAnthony Schaeffer More articles by this author , and Praveen ThumbikatPraveen Thumbikat More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.514AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Chronic pelvic pain syndrome (CPPS) is a common disorder with limited effective treatments due to its unknown etiology. Previous studies from our laboratory have demonstrated that intra-urethral infection with a uropathogenic E. coli strain isolated from a CPPS patient, named CP1 (chronic pain-1), induces chronic inflammation and tactile allodynia in a murine model of the disease. More recently we have also demonstrated that a commensal bacterial strain, named NPI (non-pain inducing) isolated from a healthy control was capable of reducing pain and inflammation in an experimental autoimmune prostatitis murine model. This study focuses on the interplay between these human bacterial strains in the context of pain development and the host immunological response to pathogenic versus commensal colonization. METHODS Male NOD/ShiLtJ mice were inoculated intra-urethrally with either NP1 (S. epidermidis) or CP1 (E. coli), and pelvic tactile allodynia responses measured every seven days by Von Frey Filament behavioral testing. At the experimental endpoint, prostate and bladder tissues were excised and colony formation assays performed. Competitive growth and invasion assays were performed in vitro. Prostate tissue lysates were also used to perform a multiplex luminex bead array to quantify host cytokine and chemokine levels. RESULTS Intra-urethral infection with the pathogenic CP1 induced pelvic tactile allodynia after seven days that became chronic after 14 days. Intra-urethral instillation with the commensal NPI strain seven days prior to infection prevented onset of pelvic tactile allodynia by CP1. Prior instillation with NPI also prevented CP1 colonization of both the prostate and bladder of mice. NPI instillation seven days after infection with CP1 significantly reduced pelvic tactile allodynia. Colony formation assays from prostate and bladder tissues of these mice demonstrated that prior infection CP1 did not significantly reduce the ability of NPI to colonize the prostate. In vitro growth kinetic analysis revealed that CP1 and NPI do not directly inhibit the growth or invasive capacities of each other. Luminex bead array revealed a specific host immune response to single or dual bacterial colonization. CONCLUSIONS Our study demonstrates that commensal bacteria in the human prostate can inhibit the colonisation and pain responses to uropathogenic bacteria, emphasizing the power of the prostatic commensal microflora in controlling health and disease. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e189 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Stephen Murphy More articles by this author Anthony Schaeffer More articles by this author Praveen Thumbikat More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Transmission Fitness in Co-colonization and the Persistence of Bacterial Pathogens.

Humans are often colonized by polymorphic bacteria such as Streptococcus pneumoniae, Bordetella pertussis, Staphylococcus Aureus, and Haemophilus influenzae. Two co-colonizing pathogen clones may interact with each other upon host entry and during within-host dynamics, ranging from competition to facilitation. Here we examine the significance of these exploitation strategies for bacterial spread and persistence in host populations. We model SIS epidemiological dynamics to capture the global behavior of such multi-strain systems, focusing on different parameters of single and dual colonization. We analyze the impact of heterogeneity in clearance and transmission rates of single and dual colonization and find the criteria under which these asymmetries enhance endemic persistence. We obtain a backward bifurcation near [Formula: see text] if the reproductive value of the parasite in dually infected hosts is sufficiently higher than that in singly infected ones. In such cases, the parasite is able to persist even in sub-threshold conditions, and reducing the basic reproduction number below 1 would be insufficient for elimination. The fitness superiority in co-colonized hosts can be attained by lowering net parasite clearance rate ([Formula: see text]), by increasing transmission rate ([Formula: see text]), or both, and coupling between these traits critically constrains opportunities of pathogen survival in the [Formula: see text] regime. Finally, using an adaptive dynamics approach, we verify that despite their importance for sub-threshold endemicity, traits expressed exclusively in coinfection should generally evolve independently of single infection traits. In particular, for [Formula: see text] a saturating parabolic or hyperbolic function of [Formula: see text], co-colonization traits evolve to an intermediate optimum (evolutionarily stable strategy, ESS), determined only by host lifespan and the trade-off parameters linking [Formula: see text] and [Formula: see text]. Our study invites more empirical attention to the dynamics and evolution of parasite life-history traits expressed exclusively in coinfection.

CARRIAGE OF MULTIDRUG RESISTANT ENTEROCOCCUS FAECIUM AND ENTEROCOCCUS FAECALIS AMONG APPARENTLY HEALTHY HUMANS.

Background:Enterococci are indigenous flora of the gastro-intestinal tracts of animals and humans. Recently, interest in two major species, E. faecium and E. faecalis, has heightened because of their ability to cause serious infections and their intrinsic resistance to antimicrobials. This study was aimed at determining the prevalence of E. faecium and E. faecalis in human faecal samples and evaluating the susceptibility of the isolates to antibiotics.Materials and Methods:One hundred faecal samples were collected from apparently healthy individuals and analysed using conventionalbacteriological methods. The susceptibility profile of the isolates to nine antibiotics were determined using disk diffusion method.Results:Seventy-three (73) Enterococcus were phenotypically identified and 65 of the isolates were differentiated into 36 (55.4%) E. faecium and 29 (44.6%) E. faecalis. Eight (8) isolates could not be identified by the conventional biochemical methods employed. No dual colonization by the E. faecalis and E. faecium was observed and isolation rate was not dependent on sex of the participants. All the isolates were resistant to ceftriaxone, cefuroxime and ceftizoxime. Enterococcus faecium exhibited resistance toerythromycin (88.9%), gentamicin (77.8%), amoxicillin-clavulanate (63.9%), ofloxacin (44.4%), teicoplanin (19.4%) and vancomycin (16.7%). Enterococcus faecalis showed the least resistance to vancomycin (13.8%) and teicoplanin (27.7%). Remarkable multiple antibiotic resistances to the classes of antibiotic tested were observed among the two species.Conclusion:The high carriage rate of antibiotic resistant E. faecium and E. faecalis in this study provides information on the local antibiotic patterns of our enterococci isolates thereby suggesting that they could present as important reservoir and vehicle for dissemination of resistant genes in our community.

Sweet vernal grasses (Anthoxanthum) colonized African mountains along two fronts in the Late Pliocene, followed by secondary contact, polyploidization and local extinction in the Pleistocene.

High tropical mountains harbour remarkable and fragmented biodiversity thought to a large degree to have been shaped by multiple dispersals of cold-adapted lineages from remote areas. Few dated phylogenetic/phylogeographic analyses are however available. Here, we address the hypotheses that the sub-Saharan African sweet vernal grasses have a dual colonization history and that lineages of independent origins have established secondary contact. We carried out rangewide sampling across the eastern African high mountains, inferred dated phylogenies from nuclear ribosomal and plastid DNA using Bayesian methods, and performed flow cytometry and AFLP (amplified fragment length polymorphism) analyses. We inferred a single Late Pliocene western Eurasian origin of the eastern African taxa, whose high-ploid populations in one mountain group formed a distinct phylogeographic group and carried plastids that diverged from those of the currently allopatric southern African lineage in the Mid- to Late Pleistocene. We show that Anthoxanthum has an intriguing history in sub-Saharan Africa, including Late Pliocene colonization from southeast and north, followed by secondary contact, hybridization, allopolyploidization and local extinction during one of the last glacial cycles. Our results add to a growing body of evidence showing that isolated tropical high mountain habitats have a dynamic recent history involving niche conservatism and recruitment from remote sources, repeated dispersals, diversification, hybridization and local extinction.

Tertiary remnants and Holocene colonizers: Genetic structure and phylogeography of Scots pine reveal higher genetic diversity in young boreal than in relict Mediterranean populations and a dual colonization of Fennoscandia

AbstractAimScots pine is one of the dominant tree species in forest ecosystems of the temperate and boreal zones in Eurasia. Since the Tertiary, it has persisted also in the Mediterranean region, forming relict populations. In this study, we investigate range‐wide genetic diversity of Scots pine, aiming to provide comprehensive information on the phylogeography and genetic resources of the species.LocationEurope and Asia.MethodsThirteen paternally inherited chloroplast microsatellite (cpSSR) loci were used to investigate the genetic structure of 62 populations from Fennoscandia and 30 populations from the Mediterranean. We also surveyed variability of two maternally inherited mitochondrial DNA (mtDNA) regions and additionally included literature data from 156 populations (248 populations in total).ResultsScots pine retains an overall high genetic diversity in the chloroplast genome but, unexpectedly, the historically younger populations from Fennoscandia showed statistically higher mean intrapopulation diversity than the Mediterranean stands (0.807 and 0.750, respectively). The latter also contained a lower number of private cpSSR haplotypes. Population differentiation with respect to mtDNA was higher (GST = 0.628) than at cpSSR (GST = 0.015) indicating an efficient pollen‐mediated gene flow among refugial populations of the species. One novel haplotype mtDNA was found, increasing the number of known mitotypes for the species from 4 to 5. The geographic distribution of mitotypes was structured into four groups corresponding to the main refugial areas of the species.Main conclusionsGenetic impoverishment of the Mediterranean populations may enhance their vulnerability to future environmental changes. The spatial distribution of two mitotypes in Fennoscandia, featuring predominance of mitotype a in Norway and Sweden and mitotype b in Finland, gives strong support for dual colonization of that region from south‐eastern (Finland) and south‐western (Sweden) directions. These results thus provide new insights into both Holocene expansion of Scots pine and the present distribution of species' genetic resources.

Enhanced Detection of Vaccine Type Colonization and Dual Serotype Carriage with Molecular Strategies for Identification of Streptococcus pneumoniae Colonization

BackgroundDetecting Streptococcus pneumoniae (SP) carriage in children via conventional microbiological methods lacks sensitivity as high density is required for routine culture and identification of dual serotype colonization is a technical challenge. To increase understanding of post vaccine nasopharyngeal (NP) carriage, specifically persistence of vaccine serotypes, strategies for molecular identification of SP have been developed. These methods most often rely on the identification of the SP autolysin gene lytA through non-quantitative PCR or semi-quantitative real-time PCR (RTPCR).MethodsWe collected NP swabs from 600 healthy or sick children <5 years old at Boston Medical Center from Nov 2015 – Mar 2016 and used enhanced microbiologic culture and molecular identification strategies to characterize SP colonization. NP specimens were broth enriched for 4 hours and cultured on selective blood agar; routine microbiologic methods were used to isolate and identify SP. A second aliquot of enriched broth was used for DNA isolation. RTPCR assays were performed targeting the lytA, piaB (SP membrane permease), cpsA (SP capsule operon) genes, and 21 SP serotypes: all serotypes included in 13-valent pneumococcal conjugate vaccine and 8 additional non-vaccine serotypes.ResultsIn our sample, 16% of specimens were SP positive via culture and 33% were RTPCR-positive (Cq≤35) for the lytA gene. Multiplex RTPCR assays with both the lytA and piaB genes yielded a positive result for 24% of samples. Further RTPCR confirmed that 99% of the lytA/piaB positive samples were positive for cpsA (a second marker for assay validation) but only 70% of the lytA positive, paiB negative samples were cpsA positive. Serogroup 19 was the most frequently isolated vaccine serogroup using both culture and RTPCR; molecular analysis identified 6% of specimens with concurrent carriage of more than one serotype.ConclusionCompared with enhanced culture, we found a 50% increase in SP detection using combined lytA and piaB multiplex RTPCR. Similarly, the proportion of children colonized with vaccine serotypes increased from 2% to 7%. This work is funded by an investigator initiated grant to BUMC from Pfizer.Disclosures K. M. Shea, Pfizer, Inc: Consultant and Grant Investigator, Consulting fee and Grant recipient; S. I. Pelton, Pfizer: Board Member and Grant Investigator, Consulting fee, Research grant and Speaker honorarium; Merck vaccines: Board Member, Consulting fee and Speaker honorarium; GSK: Board Member, Consulting fee and Speaker honorarium; Sequiris: Board Member, Consulting fee and Speaker honorarium

Origin and introduction history of the least weasel (Mustela nivalis) on Mediterranean and Atlantic islands inferred from genetic data

Introduced mammalian predators have negatively affected native biota and ecological processes in ecosystems across the globe. The least weasel (Mustela nivalis) is a Holarctic mustelid carnivore that has been considered one of the world’s worst invasive alien species. It has been introduced to several islands in the Mediterranean Sea and Atlantic Ocean, and here we present a genetic analysis of these insular populations, based on mitochondrial DNA and microsatellites and building upon a previous Western Palearctic phylogeographic study, with the aim of inferring their origin and introduction history. This is essential information for ecological and evolutionary studies of those populations and our understanding of their impacts on the islands’ biodiversity. Among the Mediterranean insular populations, a substantial mitochondrial subdivision between weasels in Sicily-Corsica and Malta-Sardinia-Balearics is best explained by a dual colonization originating from the Eastern Mediterranean. Given the correspondence between the observed genetic partition and the differential geographic distribution of Greek and Phoenician settlements and influence during the last millennium BC in those islands, we propose that weasels may have been introduced into the first group of islands by the Greeks and into the second group by the Phoenicians. There is strong support that the commercial and demographic expansions of Phoenicians and Greeks allowed the colonization of the western Mediterranean islands by the house mouse, and texts from Classical Antiquity show evidence that weasels were used for rodent control. Thus, weasels may have been intentionally introduced to the islands, with the aim of controlling commensal rodents. Besides indicating Eastern Mediterranean origins for weasels in Mediterranean islands, the mitochondrial data also revealed an unanticipated close genealogical connection between some of these populations and those from the Azores and Sao Tome. The latter island populations showed no affinities with weasels from mainland Portugal, contrary to what might have been expected given that these Atlantic islands were settled by the Portuguese. The microsatellite data also supported the relationship between weasels in Atlantic and in Mediterranean islands. Considering geographic proximity and historical information, the most parsimonious explanation for the origin of the Atlantic weasels appears to be introduction from the Balearic Islands to the Azores and from there to Sao Tome.