The genus Serratia revisited by genomics

The genus Serratia has been studied for over a century and includes clinically-important and diverse environmental members. Despite this, there is a paucity of genomic information across the genus and a robust whole genome-based phylogenetic framework is lacking. Here, we have assembled and analysed a representative set of 664 genomes from across the genus, including 215 historic isolates originally used in defining the genus. Phylogenomic analysis of the genus reveals a clearly-defined population structure which displays deep divisions and aligns with ecological niche, as well as striking congruence between historical biochemical phenotyping data and contemporary genomics data. We highlight the genomic, phenotypic and plasmid diversity of Serratia, and provide evidence of different patterns of gene flow across the genus. Our work provides a framework for understanding the emergence of clinical and other lineages of Serratia

Resistance against two lytic phage variants attenuates virulence and antibiotic resistance in Pseudomonas aeruginosa

BackgroundBacteriophage therapy is becoming part of mainstream Western medicine since antibiotics of clinical use tend to fail. It involves applying lytic bacteriophages that self-replicate and induce cell lysis, thus killing their hosts. Nevertheless, bacterial killing promotes the selection of resistant clones which sometimes may exhibit a decrease in bacterial virulence or antibiotic resistance.MethodsIn this work, we studied the Pseudomonas aeruginosa lytic phage φDCL-PA6 and its variant φDCL-PA6α. Additionally, we characterized and evaluated the production of virulence factors and the virulence in a Galleria mellonella model of resistant mutants against each phage for PA14 and two clinical strains.ResultsPhage φDCL-PA6α differs from the original by only two amino acids: one in the baseplate wedge subunit and another in the tail fiber protein. According to genomic data and cross-resistance experiments, these changes may promote the change of the phage receptor from the O-antigen to the core lipopolysaccharide. Interestingly, the host range of the two phages differs as determined against the Pseudomonas aeruginosa reference strains PA14 and PAO1 and against nine multidrug-resistant isolates from ventilator associated pneumonia.ConclusionsWe show as well that phage resistance impacts virulence factor production. Specifically, phage resistance led to decreased biofilm formation, swarming, and type III secretion; therefore, the virulence towards Galleria mellonella was dramatically attenuated. Furthermore, antibiotic resistance decreased for one clinical strain. Our study highlights important potential advantages of phage therapy’s evolutionary impact that may be exploited to generate robust therapy schemes

Cultura de consumo y tendencias de Marketing en Guayaquil: compendio de artículos

Esta recopilación de artículos académicos aborda diversas estrategias manejadas por las pymes ecuatorianas. Temas como neuromarketing, marketing digital, cultura de consumo y comportamiento de compra, son claves para dar respuestas a los consumidores. Con estudios de caso —desde lo que compran clientes de supermercados, consumo de bebidas o prendas de vestir— los textos que acá se recogen establecen perfiles de consumo en el Ecuador. Dieciocho autores que —como parte de su trabajo de titulación de Administración de Empresas de la Universidad Politécnica Salesiana— ponen sobre la mesa variables de creatividad e innovación que requieren las empresas para que el cliente busque y encuentre lo que el mercado le ofrece. Los investigadores plantean temas como el creciente comercio electrónico o los servicios bancarios en línea y las preferencias del consumidor ecuatoriano, dando así pistas a las pequeñas empresas sobre la cultura de compra del consumidor en el país

Metodología de CNC para diseñar la base de una licuadora

IM 195 CNC DISEÑO BASE LICUADOR

The phylogenomic landscape of the genus Serratia

The genus Serratia has been studied for over a century and includes clinically-important and diverse environmental members. Despite this, there is a paucity of genomic information across the genus and a robust whole genome-based phylogenetic framework is lacking. Here, we have assembled and analysed a representative set of 664 genomes from across the genus, including 215 historic isolates originally used in defining the genus. Phylogenomic analysis of the genus reveals a clearly-defined population structure which displays deep divisions and aligns with ecological niche, as well as striking congruence between historical biochemical phenotyping data and contemporary genomics data. We show that Serratia is a diverse genus which displays striking plasticity and ability to adapt to its environment, including a highly-varied portfolio of plasmids, and provide evidence of different patterns of gene flow across the genus. This work provides an essential platform for understanding the emergence of clinical and other lineages of Serratia

Selection of Functional Quorum Sensing Systems by Lysogenic Bacteriophages in Pseudomonas aeruginosa

Quorum sensing (QS) in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored. Therefore, in this work, we studied the effects of having a functional QS system on the susceptibility to temperate bacteriophages and how this affects the bacterial and phage dynamics. We find that both experimentally and using mathematical models, that the lysogenic bacteriophages D3112 and JBD30 select QS-proficient P. aeruginosa phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella, in spite of the fact that both phages replicate better in the wild-type background. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS

Selection of functional quorum sensing systems by lysogenic bacteriophages in <em>Pseudomonas aeruginosa</em>.

Quorum sensing (QS) in Pseudomonas aeruginosa coordinates the expression of virulence factors, some of which are used as public goods. Since their production is a cooperative behavior, it is susceptible to social cheating in which non-cooperative QS deficient mutants use the resources without investing in their production. Nevertheless, functional QS systems are abundant; hence, mechanisms regulating the amount of cheating should exist. Evidence that demonstrates a tight relationship between QS and the susceptibility of bacteria against the attack of lytic phages is increasing; nevertheless, the relationship between temperate phages and QS has been much less explored. Therefore, in this work, we studied the effects of having a functional QS system on the susceptibility to temperate bacteriophages and how this affects the bacterial and phage dynamics. We find that both experimentally and using mathematical models, that the lysogenic bacteriophages D3112 and JBD30 select QS-proficient P. aeruginosa phenotypes as compared to the QS-deficient mutants during competition experiments with mixed strain populations in vitro and in vivo in Galleria mellonella, in spite of the fact that both phages replicate better in the wild-type background. We show that this phenomenon restricts social cheating, and we propose that temperate phages may constitute an important selective pressure toward the conservation of bacterial QS

Genomic epidemiology reveals multidrug resistant plasmid spread between Vibrio cholerae lineages in Yemen.

Acknowledgements: This research was funded in whole, or in part, by the Wellcome Trust (grant nos 206194 and 108413/A/15/D). This work was supported by Institut Pasteur, Santé publique France, and by the French Government’s Investissement d’Avenir programme, Laboratoire d’Excellence ‘Integrative Biology of Emerging Infectious Diseases’ (grant no. ANR-10-LABX-62-IBEID). F.L., M.J.D., G.A.B., A.T.-B., M.A.B., A.C. and N.R.T. were supported by Wellcome funding to the Sanger Institute (grant nos 206194 and 108413/A/15/D). E.N., J.R., M.-L.Q. and F.-X.W. were supported by French Government funding to Institute Pasteur (grant no. ANR-10-LABX-62-IBEID). We thank J. Woolfolk, S. Clare and C. Tolley for their support in sample management at Wellcome Sanger Institute, as well as the Sanger Pipelines team for support. M.J.D. is an Official Fellow of Churchill College, Cambridge, and was previously supported by a Junior Research Fellowship at the College. For the purpose of Open Access, the author has applied a CC-BY public copyright licence to any author accepted manuscript version arising from this submission.Funder: LABoratoire d’EXcellence IBEID (Labex IBEID); ANR-10-LABX-62-IBEIDSince 2016, Yemen has been experiencing the largest cholera outbreak in modern history. Multidrug resistance (MDR) emerged among Vibrio cholerae isolates from cholera patients in 2018. Here, to characterize circulating genotypes, we analysed 260 isolates sampled in Yemen between 2018 and 2019. Eighty-four percent of V. cholerae isolates were serogroup O1 belonging to the seventh pandemic El Tor (7PET) lineage, sub-lineage T13, whereas 16% were non-toxigenic, from divergent non-7PET lineages. Treatment of severe cholera with macrolides between 2016 and 2019 coincided with the emergence and dominance of T13 subclones carrying an incompatibility type C (IncC) plasmid harbouring an MDR pseudo-compound transposon. MDR plasmid detection also in endemic non-7PET V. cholerae lineages suggested genetic exchange with 7PET epidemic strains. Stable co-occurrence of the IncC plasmid with the SXT family of integrative and conjugative element in the 7PET background has major implications for cholera control, highlighting the importance of genomic epidemiological surveillance to limit MDR spread