- Volume 1, Issue 1A, 2019
Volume 1, Issue 1A, 2019
- Poster Presentation
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- Fighting Fire with Fire – Deploying Microbes in the Battle Against Disease
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Moonlighting in myxobacteria: measuring the covariation in GAPDH
More LessMyxobacteria are an order of well-known social predators that able to prey upon a wide range of microbes (including fungi and bacteria). It is currently unknown how they are able to consume such a wide range of prey, although moonlighting proteins, those possessing more than one function, appear to be involved. One moonlighter, is the virtually ubiquitous enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Typically present in the cytoplasm, it has also been found on the outer surface of cells, in the extracellular matrix, and secreted through membrane vesicles. In various pathogenic organisms, GAPDH has been shown to have adhesive properties, binding to several types of human connective tissues. Myxobacterial predation can be viewed as analogous to pathogenic infection, and there is evidence that GAPDH might be involved in attacking prey cells. To complement experimental analyses of the predatory role of GAPDH in myxobacteria, we undertook sequence analysis including multiple sequence alignment (MSA) and covariation analyses. Covariation calculations, using a variety of metrics and matrices, have been used to identify areas and individual residues where structural, functional or phylogenetic correlations occur within the sequence. The MSA data highlighted key conserved residues, likely involved in the catalytic reaction and potentially involved in adhesion. The covariation scores suggest compensatory mutations have taken place in discrete locations along the sequence. These results can be used to selectively mutate residues in order to determine their effect in predation.
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Penicillium spp. strains as a possible weapon to fight microbial infections
More LessBacteria are becoming increasingly resistant to antibiotics, leading to untreatable infections and constituting a major public health hazard (Lewis, 2013). This problem is further increased by the reduction in the number of effective antibiotics to tackle resistant strains (Penesyan et al. 2015), so the search for new compounds is seen as a vital priority. Our study consisted in the analysis of four different environmental strains of Penicillium spp., with screening for their extracellular metabolites for potential antimicrobial activity. Several methods were combined and tested for metabolite production and extraction. The strains were grown on: solid media (I-potato dextrose agar and II-malt extract agar), broth (malt extract broth with III-0 and IV-5% NaCl), and V-tapwater; extractions were performed using three different solvents: A-methanol, B-butanol and C-ethyl acetate. All extracts were tested on three different model organisms: Micrococcus luteus, Escherichia coli and Mycobacterium smegmatis. These are models for Gram-positive and Gram-negative bacteria, and for Tuberculosis. The extracts were compared and analysed in order to determine minimal inhibitory concentrations for each of the microorganisms tested. This research presents preliminary results on the development of potential new chemical compounds to help us circumvent the problem of drug resistance. Lewis, K., 2013. Platforms for antibiotic discovery. Nature reviews Drug discovery, 12(5), pp.371–387. Penesyan, A., Gillings, M. and Paulsen, I.T., 2015. Antibiotic discovery: combatting bacterial resistance in cells and in biofilm communities. Molecules, 20(4), pp.5286–5298.
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Identification and characterization of bioengineered nisin derivatives that inhibit the opportunistic pathogen Staphylococcus epidermidis
More LessStaphylococcus epidermidis is a major cause of hospital-acquired infections particularly on indwelling medical devices and implants. Infections caused by this pathogen are difficult to treat with standard antimicrobial agents mainly as the bacterium can establish biofilms on artificial surfaces. Novel control methods are needed and one such alternative may be bacteriocins; these are antimicrobial peptides produced by some bacteria that inhibit other specific bacteria. They are potent, safe, and stable and are easy to produce using biotechnological based strategies. Additionally, as they are gene encoded they can be easily modified or engineered to enhance their activity. In the present study, we demonstrate the ability of the bacteriocin nisin to inhibit a collection of clinical S. epidermidis strains under standard laboratory conditions. In addition, a bank of bioengineered nisin derivatives was screened using agar-based deferred antagonism assays and derivatives with enhanced antimicrobial activity compared to the wild-type nisin were identified. These derivative peptides are currently being purified using a combination of chromatography-based approaches and their potency and stability are being examined. Future experiments will focus on examining the ability of the nisin derivatives in inhibiting S. epidermidis biofilms on medical device materials (e.g. stainless steel and polyvinyl chloride) both alone and in combination with conventional antibiotics. It is hoped that one of the nisin derivatives analysed in this study may ultimately be used to control or prevent infections caused by S. epidermidis.
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Endophytic actinobacteria of herbal rhizomes and their pharmaceutical potential to form L-asparaginase
Pharmaceutical treasure of herbs is well known and some of which have long been served as natural medicines or nourishments to enrich human health. It is conceivable that herbs offer unique habitats for endophytic microbes. Interestingly, the metabolic exchange between endophytes and their herbal hosts does not only allow the microbial subsistence but also enable them to form analog bioactive substances to those produced by their hosts. These challenge us to focus on searching for beneficial microbes from herbs and industrialize them as the producers of pharmaceutical products. In this work, we isolated 37 actinobacteria from rhizomes of fingerroot (Boesenbergia rotunda), ginger (Zingiber officinale), galangal (Alpinia galanga) and turmeric (Curcuma longa). These actinobacteria were classified preliminarily based on their morphology to the genus Streptomyces (86 %) and other unknown genera (14 %). To screen for anticancer activity, we found that 68% of all isolated actinobacteria produced L-asparaginase, which is a hydrolytic enzyme that acts as an inhibitor of leukemia. Streptomyces sp. ALP03 was among the active isolates exhibited the highest enzyme activity of L-asparaginase and showed a maximum 97.93 % similarity of its 16S rRNA gene sequence to Streptomyces spongiae Sp080513SC-24T. The cytotoxicity assays against diverse types of cancer cell lines will be carried out to assess the anticancer potential of isolate ALP03 and the others showing distinct L-asparaginase activity. With these findings, we conclude that herbal rhizomes have yet been a promising source for the discovery of useful microbes and their pharmaceutical products.
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Screening bacteriophage activity against E. coli O157:H7 attached to host cells
More LessBacteriophage (phage) therapy, the use of a specific virus to kill infecting bacteria, is often cited as an alternative to antibiotic therapy. But phage treatment could also play an important role in bio-security against the foodborne pathogen E. coli O157:H7. Phage can be relatively easily isolated and shown to have activity against bacterial strains of interest under laboratory conditions. However, to be used successfully for treatment the phage must be active in vivo where the bacteria may be attached to host cells. To overcome this potential hurdle we are using a screen to test phage activity in conditions more realistic to the host environment than standard lab media. As part of this work we have been isolating new phage that are active against E. coli O157:H7 strains. We are currently testing these newly isolated phage against different bacterial strains and under a variety conditions looking for characteristics that will make them good candidates for phage therapy. We will then test the activity of promising candidates against E. coli O157:H7 attached to bovine epithelial (EBL) cells. The aim of this work is to put together a panel of around 20 phage that not only have the appropriate standard characteristics for phage therapy but have also been shown to have activity on attached bacterial cells. The longer term aim of this work is to use these ‘in vivo’ active phage as an intervention on cattle colonized with E. coli O157:H7 thereby reducing the potential of this pathogen entering the food chain.
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Creation and characterisation of probiotic libraries for use in poultry and pigs
More LessProbiotics are defined as live micro-organisms which provide the host with a growth or health advantage. In recent year’s with the emergence of antimicrobial resistance, probiotics, and in particular Lactobacillus, have become increasingly popular as an alternative control strategies for bacterial pathogens. Recent studies have demonstrated that Lactobacillus is not only able to increase the growth rate of animals, an important consideration for commercial farming entities, but is also able to inhibit the colonisation of animals with pathogenic bacteria species such as Salmonella, Campylobacter and Escherichia. This study aimed to isolate and characterise lactobacilli isolates from commercially reared chickens and pigs. Particular attention was paid to the probiotic potential of the isolates. Our approach combined molecular techniques with in vitroscreening to rapidly identify this potential. To date 80 and 105 isolates have been collected from pigs and chickens, respectively. All isolates have been confirmed to belong to the Lactobacillus genus by PCR, speciated by 16S sequencing and determined to be clonally unique using RAPD PCR. Isolates were subsequently tested for their ability to tolerate low pH, bile, aerobic and anaerobic conditions before assessing their AMR profile and determine their ability to inhibit a panel of clinical and type strains of pathogenic bacteria. Isolates identified as potential probiotics are currently undergoing whole genome sequenced as per EFSA guidelines. This study has demonstrated that lactobacilli isolates with suitable probiotic properties can be isolated from commercial poultry and pigs. Furthermore, these isolates may prove useful as control strategies for zoonotic bacterial pathogens.
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Targeting antimicrobial resistance genes in clinical isolates from healthcare-associated infections using CRISPR-Cas9
Of the numerous approaches to counteracting the spread of antimicrobial resistance (AMR), one that is receiving increased attention is the use of CRISPR-Cas-based gene editing technology to remove resistance-conferring sequences from bacteria. Proof-of-principle studies have shown that CRISPR-Cas is able to successfully remove AMR genes from monocultures or very simple bacterial communities in the laboratory, but these constructs and their delivery must be adapted to be used in real-world medical settings. One area where such a technology may be implemented is tackling healthcare-associated infections. Development of a CRISPR-Cas9 cassette that is able to target particular resistance genes would be a powerful tool in addressing these infections. CRISPR-Cas9 will therefore be implemented to target AMR genes in clinical isolates of vancomycin-resistant Enterococcus faecium, and extended-spectrum β-lactamase (CTX-M) or carbapenemase (Oxa-48)-producing Klebsiella pneumoniae and Escherichia coli, by utilising a broad host range conjugative plasmid to deliver this construct via conjugation. Preliminary work using E. coli MG1655 as plasmid donor have shown that all strains can receive the plasmid, and there is significant variation in conjugation frequency between E. coli recipients.
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Investigating soil bacteria for novel antimicrobials which inhibit the opportunistic pathogen, Staphylococcus epidermidis
More LessAccording to the European Center of Disease Control and Prevention, Staphylococcus epidermidis is rapidly becoming a serious concern in hospitals as a cause of resistant infections, particularly in the case of in dwelling and prosthetic medical devices. To overcome this issue, new, potent antimicrobials with novel target pathways need to be uncovered to both reduce morbidity and mortality, and the spread of resistant microbes. 51 bacterial strains with observable antimicrobial activity against S. epidermidis were isolated from samples of soil, collected from various locations around Ireland. The activity was reconfirmed, and the most effective strains were shortlisted using deferred antagonism assays. Characterisation tests, (Gram stains, oxidase and catalase testing and 16S sequencing), were carried out to determine the identities of the bacteria at hand. Presently studies are underway to elucidate the nature of the antimicrobial activity and to govern if the findings are novel. HPLC is being used to purify the compounds, with proteinase K assays evaluating if the antimicrobials are proteinaceous in nature. The future of this study will include the sequencing of any uncovered antimicrobial peptides, MIC determination of antimicrobial compounds, observing the impact on biofilm formation and looking at potential efficacy against other relevant pathogens. With the identification of a novel compounds, this study aims to present an opening into potential new treatment options to help address the current struggle against antimicrobial resistance.
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- Focus on 3Rs – The Growing Role of Organoids and Microbial Models to Understand Human and Animal Diseases
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Exploring the metabolic potential of oleaginous actinomycetes in biodiesel production from cassava wastewater
More LessThe depletion in fossil fuel reserves has instigated the search for renewable sources such as biofuels. Biofuel production provides a sustainable alternative to fossil fuels. However, the progression of biofuel industry has been largely affected by several uncertainties including the sustainability of production processes. Finding an economically viable process and the right substrates have been a source of constant debate. Biodiesel production is one such area which is gaining momentum in the last few decades. We are currently investigating cassava wastewater as a substrate and also as a source of oleaginous bacteria. The production of tri-acyl glycerol from mycolic acid containing actinomycetes predominantly Rhodococcus, has been identified as a potential source. These bacteria which are largely ubiquitous provide a significant amount of triglyceride when cultivated under low cost waste. The growth of oleaginous bacteria for the accumulation of triglycerides on low cost and abundant, cassava waste still remains unexplored, especially in Nigeria which is the largest producer of cassava in the world. We started our initial investigations on the cassava waste water sample following culture dependent and independent approach. We prognosticate that the identification of microflora isolated from different stages in the sample will provide a basis for understanding the nature of the substrate and the potential for the synthesis of biodiesel from cassava waste water.
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Galleria mellonella: a novel infection model for screening potential anti-mycobacterial compounds against members of the Mycobacterium tuberculosis complex
More LessAnimal infection models are vital as drug screens for novel therapeutics to tackle the global tuberculosis (TB) epidemic. However, all pre-existing models have limitations which include ethical constraints. Therefore, efforts to reduce and/or replace conventional animal models in TB research are warranted. Previously, we reported the use of Galleria mellonella (greater wax moth, GM) as a novel infection model for the Mycobacterium tuberculosis (MTB) complex, using Mycobacterium bovis BCG lux, a bioluminescent mutant which allows for the rapid quantification of bacterial burden in vivo. Here we investigated the drug screening potential of GM infected with a lethal dose of BCG lux, treated with first or second-line antimycobacterial drugs over a 96 h period; where drug efficacy was determined every 24 h through bioluminescent measurement of larval homogenates. Improved survival outcome was observed in all larvae treated with antimycobacterials when compared to untreated controls. Furthermore, all drug treatments except pyrazinamide resulted in a significant reduction in bioluminescence of BCG lux in vivo. Isoniazid and rifampicin displayed the highest survival outcome and greatest in vivo drug efficacy, in line with observations reported in mice. However, combined or multiple dosing of either drug showed little to no difference over single dose mono-therapy. Our results demonstrate that GM is a promising infection model for members of the MTB complex, with significant potential for its use in the drug development pipeline as a pre-screening model for novel therapeutics, thereby reducing experimental usage of animals in TB research. Supported by the NC3R’s (NC/R001596/1)
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The Dictyostelium rhomboid proteases and mitochondrial disease
More LessRhomboid membrane proteases are integral to pathogenicity of several microbial eukaryotes and the role of mitochondrial rhomboids is important in pathologies beyond infectious disease. By virtue of their ability to cleave tethered proteins, this relatively recently discovered protein family have been found to activate substrates, release mobile signals, and progress cell regulatory pathways. The Dictyostelium model microbe allows the study of an evolutionarily ancient set of rhomboids, aberrant expression of which affects phagocytosis, response to chemoattractants, phototaxis, growth and cell size, ATP levels, and mitochondrial ultrastructure. We report the particularly mitochondrial focus of rhomboids in this amoeba and consider the relevance of this beyond the model organism, given the central role of the human mitochondrial rhomboid in mitophagy, ageing and neurodegenerative disease.
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Comparison of MRSA skin infection models with HaCaT keratinocytes and a 3D-organotypic skin model
More LessBackground and AimsSkin is a major site for Staphylococcus aureus colonization and invasion. A 3D-organotypic skin model was generated by co-culturing keratinocytes with fibroblasts at air-liquid interface enabling the proliferation, migration and differentiation of the keratinocyte to mimic terminal differentiation of the epidermis.
MethodsThe adherence and internalization of MRSA strain types ST8, ST30, ST59, ST22, ST45 and ST239 were evaluated in the HaCaT keratinocytes and a 3-D organotypic skin model. Acridine orange staining and/or anti-Staphylococcus aureus antibody were used for bacterial localization. TUNEL assay was used to evaluate cell death due to apoptosis.
ResultsMaximum adherence to HaCaT cells were exhibited by both MRSA ST59 and ST8 strain types (P=0.129, Tukey post-hoc test). The maximum percentage of internalization was exhibited by both ST59 and ST30. With ST8, ST30, ST59 and ST239 types, bacteria were present within the cytoplasm whereas localization of ST22 and ST45in the phagosomes of HaCaT keratinocytes were observed. Study of cell death in HaCaT keratinocytes was limited to 24 h due to dislodgement of the keratinocytes with all six strains. The 3-D skin model proved to be better to study MRSA transmigration and cell death which could be monitored for longer time points. ST59 exhibited maximum adhesion and internalization.
ConclusionThe 3-D skin model proves to be a better model to study MRSA skin infections.
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Pigs, PAMs and Pathogens: using primary alveolar macrophages from abattoir acquired porcine lungs to model pulmonary infections
More LessThe similarity between the porcine and human immune system makes pigs an ideal model for studying infectious disease. We have been using alveolar macrophages recovered from abattoir-sourced porcine lungs to create a model to study Streptococcus pneumoniae infections in the lung. Pneumonia is a leading cause of death from infectious disease, with S. pneumoniae the most common cause of bacterial pneumonia. Although much studied, there is still a lot we don’t know about the early stages of infection. Recent research in our lab has found a previously unknown intracellular phase for S. pneumoniae within splenic macrophages Alveolar macrophages were recovered by bronco-alveolar lavage and used in gentamicin protection assays. Macrophages challenged with S. pneumoniae at an MOI of 25 bacteria per cell were found to contain live bacteria up to 5 h after infection. Analysis of samples collected at 45, 90, 180 and 300 min after challenge found less than 10 % of the challenge dose present at 45 min, decreasing to 0.02 % after 5 h. The presence of bacteria inside the macrophages was confirmed by confocal microscopy. Studies are on-going to unpick the processes that allow the bacteria to resist phagocytosis by the macrophages, and to use the model to investigate the interaction of the macrophages with other respiratory pathogens. The use of abattoir-acquired porcine cells contributes to the 3Rs – reducing and replacing laboratory animals, and refinement of method as pigs are more akin to humans than mice. J. McNicholl is sponsored by the Daphne Jackson Trust.
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Using human iPSC derived small intestinal organoids as a model for enteric disease caused by Enterotoxigenic E. coli and Vibrio cholerae
Within the last ten years, iPSC (induced pluripotent stem cells) have been widely shown to have the ability to be re-programmed to produce a wide range of tissues in the presence of certain growth factors. In this project, we re-direct human stem cells derived from fibroblasts into complex 3D small intestinal structures termed organoids. These organoids have been shown to possess all cell types that are present in small intestinal tissue such as, enterocytes, goblet cells, enteroendocrine cells and Paneth cells, as well as possessing microvilli and crypt structures. We demonstrate that it is possible to microinject into the lumen of these small intestinal organoids and to manipulate the conditions for infection of non-invasive bacteria such as Enterotoxigenic E. coli (ETEC) and Vibrio cholerae. Looking at known bacterial virulence factors, we have shown there are differences in patterns of infection among different strains of entero-pathogenic bacteria. In addition, we have shown that the induced human organoids (iHO) elicit a recognisable and measurable host response to bacterial toxin.
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The utilisation of organoids and macrophages derived from Human induced pluripotent stem cells as model systems to investigate host-bacterial interactions
More LessUsing human induced pluripotent stem cell (hiPSC) technology we are developing methods to examine host-bacterial interactions. Due to the fact that undifferentiated human induced pluripotent stem cells are amenable to genetic engineering, can be cultured indefinitely and can further be differentiated into multiple cell types, we are exploiting both organoid and macrophage systems to investigate the interactions between host cells and diarrhoeal pathogens, including enterotoxigenic Escherichia coli and Vibrio cholerae. Utilising both wild type and relevant knockout hiPSC lines we are probing both initial interactions and subsequent utilisation of pathways for the effects of toxins. The further analysis of genetically engineered bacteria extend the usefulness of this model system, and complement the availability of mutant host cells, towards the simultaneous genetic analysis of both pathogen and host.
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Modelling biofilms on infected chronic wounds
More LessChronic wounds, for instance venous, pressure, arterial and diabetic ulcers, are a major health problem throughout the world. Compared with normal wounds, those that take more than four weeks to heal are defined as chronic. Interestingly, the numbers of patients suffering from chronic wounds and the cost for treatment have been increasing during the past two decades. There is increasing evidence that suggests that bacteria infect those chronic wounds and there exist as a biofilm, which affects the wound healing and success of wound treatment. To study biofilms in infected wounds, both in vitro and in vivo biofilm models have been developed. In this project, the colony biofilm assay was used to determine antibiotics effect on removing biofilm. The results of this study so far indicated that mature Staphylococcus aureus biofilms were resistant to vancomycin treatment, which works effectively on killing planktonic cells. However, other antibiotics used topically for healing infected chronic wounds, for example, gentamicin, tetracycline, fusidic acid and mupirocin, were more effective at killing mature biofilms in the colony biofilm model. These sets of experiments were also done with pig skin based on colony biofilm assay. This project aims to build up a new ex vivo dynamic model using pig skin and a 3D print flow chamber to mimic chronic wounds. Hence, the results gathered from the colony biofilm assay will be compared with those obtained for the newly developed model. This model can then be used to study the drug delivery and topical treatment of chronic wounds.
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- From Prokaryotes to Eukaryotes: The Origin and Diversity of Eukaryotes
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Development of antimicrobials against Acanthamoeba
More LessAcanthamoeba is a free-living amoeba widely distributed in the environment which exists as two stages in their life cycle: a motile and trophic replicating trophozoite and a resistant cyst stage. In recent years, the incidence of infections due to Acanthamoeba spp. has shown a remarkable increase. This parasite is the causative agent of a sight-threatening infection of the cornea known as Acanthamoeba keratitis (AK) and a fatal disease of the central nervous system known as Granulomatous Amebic Encephalitis (GAE) mainly in immunocompromised patients. Although the trophozoite form is much more readily eliminated, at present there are not harmless effective treatments or a single drug that can eliminate both cystic and trophozoite forms. A particular set of compounds known as Minor Grove Binders (MGBs) have the characteristic of binding specifically to minor groove region of double-stranded DNA. The main effects of these MGBs are their ability to interfere with biological functions of DNA such as transcription machinery, also induction of apoptosis, hence cell death. These molecules have received great attention since they can be empirically screened and iteratively refined via chemical synthesis to target various entities such as tumors, bacteria, viruses and parasites. MGBs have been tested in vitrousing a colorimetric alamar Blue viability cell assayagainst Acanthamoeba castellanii Neff strain. To date, 2 hit compounds were able to inhibit trophozoites producing IC50s of 1.56 µM and 12.5 µM.
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- Genetics and Genomics Forum
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Characterization of prophages in Salmonella Typhimurium definitive type 8
More LessBackgroundSalmonella Typhimurium DT8 has been associated with human outbreaks. Anderson phage typing scheme has been used for more than four decades for subtyping of Salmonella Typhimurium, but it has shown some limitations. Here, we characterize prophages among Salmonella Typhimurium DT8 strains to test the potential use of prophage sequence profiles for subtyping.
MethodA total of 54 isolates of Salmonella Typhimurium DT8 were selected for this study which was part of an outbreak study by Ashton et al. (2015)*. Twenty-six isolates were associated with an outbreak in the States of Jersey in 2013 and 28 isolates were non-outbreak-associated isolates. Comparative genomics using a range of bioinformatic tools was carried out including SPAdes for de novo assembly of WGS data. PHASTER was used for characterisation of prophages (http://phaster.ca/).
ResultAll DT8 strains are lysogenic for three prophages (RE-2010, ST64B and Gifsy-2). Moreover, the three prophages showed identical sequence among outbreak and non-outbreak isolates. Interestingly, prophage SSU5 was detected in one non-outbreak isolate. Prophage SSU5 is closely related to cryptic plasmid pHMC2 that infects only rough strains of Salmonella Typhimurium. This study is the first to report the presence of prophage SSU5 in Salmonella Typhimurium DT8.
ConclusionIt is crucial to use accurate, reliable and highly discriminative subtyping methods for epidemiological characterisation and outbreak investigation of Salmonella Typhimurium. Prophage profiling might be unsuitable subtyping method. The emerging genetic analysis should be combined with the conventional method for epidemiological surveillance until WGS-based analysis can be improved and standardized. *https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4336196/
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Genome-guided screening of bacterial isolates to identify potential antibiotic producers
More LessThe urgent need for new antibiotics cannot be overemphasized. Bacterial secondary metabolites remain a relatively untapped source of new therapies. The ability to produce these bioactive compounds is however not universal to all bacterial species. Two key indicators are bacterial genome size (>3 Mb), and the presence of antibiotic-encoding biosynthetic gene cluster (BGCs) within the genomes. BGC distribution is largely determined by phylogeny. Another attribute of some antibiotic producers is the ability to withstand nutritional stress. We exploited these attributes to isolate and identify potential antibiotic producers. A minimal substrate medium was used to isolate nutritionally versatile bacterial strains from topsoil collected from the rhizosphere. The genera of isolates were identified by 16S rRNA gene sequence comparison as Pseudomonas, Hafnia and Obesumbacterium. The typical genome size of species in these genera are 6.2 Mb, 4.7 Mb and 5.0 Mb respectively. The antiSMASH database was browsed by phylogeny to determine the distribution pattern of BGCs in these genera. Pseudomonas strains have an average of 7 BGCs within their genomes that may encode antibiotics, whilst Hafnia and Obesumbacterium strains have 2 and 0 respectively. Therefore, the isolated Pseudomonas strain has the greatest potential to biosynthesis antibiotics. However, the biosynthetic potential of other isolates may be understated given the typical genome size of species in their genera, and their ecological origin. Consequently, all isolates are prime candidates for the next stage of the project which involves genome mining for cryptic or silent genes that may encode novel compounds with antibiotic properties. More isolates are also being recovered.
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Characterisation of extended spectrum beta-lactamases (ESBL) resistance in multi-drug resistant Salmonella concord
More LessSalmonellosis in children from Ethiopia is caused mainly by Salmonella Concord, which are highly invasive, multi-drug resistant and extended-spectrum β-lactamase (ESBL) producers. S. Concord infections have been observed in children adopted from Ethiopia, now living in Europe and United States. S. Concord infections are present in parents of these adopted children, posing a significant dilemma for treatment. Data from Salmonella isolates are stored in Public Health England’s in-house Gastro Data Warehouse (GDW) database. Resistance profiles for 37 pure S. Concord isolates were determined using agar incorporation methods using EUCAST guidelines. The minimum inhibitory concentration (MIC) was determined for 18 antimicrobial agents and ESBL resistance was confirmed using Double Disk Synergy and ESBL E-test methods. ESBL resistance was present in 8 isolates with resistance most commonly seen against penicillins and cephalosporins. Isolates 408 and 537, and isolate 527 displayed resistance to 78 % and 56 % of the antibiotics respectively. Drug resistant regions in isolates 408, 527 and 537 that have been previously sequenced by an Illumina HiSeq 2500 were characterised. ESBL genes blaCTXM-15 was present in isolate 527 and 408 and blaSHV-12 was found in isolate 537. Replicons from plasmids, InCI2, InCFIB, InCF2 and IncH2 were located in the assembled sequences of the three previously sequenced isolates. In conclusion, the possible mechanisms causing spread of ESBL resistance in S. Concord is most likely due to acquisition of plasmids through horizontal gene transfer from various Enterobacteriaceae, however further research must be conducted to confirm this to advance antimicrobial research in this area.
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Prevalence and resistance pattern of uropathogens from community settings of different regions: an experience from India
Sarita Mohapatra, Rajashree Panigrahy, Vibhor Tak, Shwetha J. V., Sneha K. C., Susmita Chaudhuri, Swati Pundir, Deepak Kocher, Hitender Gautam, Seema Sood, Bimal Kumar Das, Arti Kapil, Pankaj Hari, Arvind Kumar, Rajesh Kumari, Mani Kalaivani, Ambica R., Harshal Ramesh Salve, Sumit Malhotra and Shashi Kant
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