#Serratia marcescens shapes cutaneous #bacterial #communities and influences #survival of an #amphibian host (Proc Roy Soc B., abstract)

[Source: Proceedings of the Royal Society, Biological Sciences, full page: (LINK). Abstract, edited.]

Serratia marcescens shapes cutaneous bacterial communities and influences survival of an amphibian host

Joseph D. Madison, Scot P. Ouellette, Emme L. Schmidt and Jacob L. Kerby

Published: 30 October 2019 / DOI: https://doi.org/10.1098/rspb.2019.1833



Ongoing investigations into the interactions between microbial communities and their associated hosts are changing how emerging diseases are perceived and ameliorated. Of the numerous host–microbiome–disease systems of study, the emergence of chytridiomycosis (caused by Batrachochytrium dendrobatidis, hereafter Bd) has been implicated in ongoing declines and extinction events of amphibians worldwide. Interestingly, there has been differential survival among amphibians in resisting Bd infection and subsequent disease. One factor thought to contribute to this resistance is the host-associated cutaneous microbiota. This has raised the possibility of using genetically modified probiotics to restructure the host-associated microbiota for desired anti-fungal outcomes. Here, we use a previously described strain of Serratia marcescens (Sm) for the manipulation of amphibian cutaneous microbiota. Sm was genetically altered to have a dysfunctional pathway for the production of the extracellular metabolite prodigiosin. This genetically altered strain (Δpig) and the functional prodigiosin producing strain (wild-type, WT) were compared for their microbial community and anti-Bd effects both in vitro and in vivo. In vitro, Bd growth was significantly repressed in the presence of prodigiosin. In vivo, the inoculation of both Sm strains was shown to significantly influence amphibian microbiota diversity with the Δpig-Sm treatment showing increasing alpha diversity, and the WT-Sm having no temporal effect on diversity. Differences were also seen in host mortality with Δpig-Sm treatments exhibiting significantly decreased survival probability when compared with WT-Sm in the presence of Bd. These results are an important proof-of-concept for linking the use of genetically modified probiotic bacteria to host microbial community structure and disease outcomes, which in the future may provide a way to ameliorate disease and address critical frontiers in disease and microbial ecology.



Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare.c.4703306

Keywords: Serratia spp.; Amphibians.


#SME-4-producing #Serratia marcescens from #Argentina belonging to clade 2 of the S. marcescens phylogeny (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

SME-4-producing Serratia marcescens from Argentina belonging to clade 2 of the S. marcescens phylogeny

Laura Dabos, Rafael Patiño-Navarrete, Marcela Nastro, Angela Famiglietti, Philippe Glaser, Carlos H Rodriguez, Thierry Naas

Journal of Antimicrobial Chemotherapy, dkz115, https://doi.org/10.1093/jac/dkz115

Published: 16 April 2019




SME carbapenemases are increasingly reported, especially from North and South America. Here, we describe an SME-4-producing Serratia marcescens(SME-Sm) clinical isolate from Argentina and compare its genome with other SME-Sm and Sm isolates recovered from public databases.


Sm isolates were characterized by WGS using Illumina technology, susceptibility testing and MIC determination. Carbapenemase activity was revealed by biochemical tests based on imipenem hydrolysis. A whole-genome phylogeny was estimated for all the Sm isolates retrieved from public databases with kSNP3 and a whole-genome phylogenetic analysis based on non-recombinant core SNPs was inferred for Sm complete genomes and for those encoding any blaSME variants.


Sm163 was resistant to amoxicillin, temocillin, aztreonam and carbapenems, remaining susceptible to extended-spectrum cephalosporins. WGS analysis of Sm163 revealed a genome of 5 139 329 bp and a chromosomally encoded blaSME-4 carbapenemase gene located on a genomic island closely related to SmarGI1-1 of Sm N11-02820. Comparison of the Sm genomes revealed that the 14 SME-Sm isolates possess this genomic island inserted at the same loci, that 13/14 belong to clade 1 and that 11/14 form a well-defined subcluster of cluster I of Sm clade 1, while Sm163 belongs to clade 2, suggesting that an SME-encoding genomic island may have been transferred between isolates from different clades.


To the best of our knowledge this is the first report of an SME-4-encoding Smfrom Argentina. The blaSME-4 gene is located on a SmarGI1-1-like genomic island. The genome of Sm163 belongs to clade 2, unlike all the other SME-Smisolates, which belong to clade 1.


© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Keywords: Antibiotics; Drugs Resistance; Carbapene; Serratia marcescens; Amoxicillin; Temocillin; Aztreonam; Argentina.


A #Gut #Commensal Bacterium Promotes #Mosquito Permissiveness to #Arboviruses (Cell Host Microbe, abstract)

[Source: Cell Host & Microbe, full page: (LINK). Abstract, edited.]

A Gut Commensal Bacterium Promotes Mosquito Permissiveness to Arboviruses

Pa Wu, Peng Sun, Kaixiao Nie, Yibin Zhu, Mingyu Shi, Changguang Xiao, Han Liu, Qiyong Liu, Tongyan Zhao, Xiaoguang Chen, Hongning Zhou, Penghua Wang, Gong Cheng 9

Published: December 27, 2018 / DOI:https://doi.org/10.1016/j.chom.2018.11.004



  • The gut commensal Serratia marcescens promotes mosquito permissiveness to arboviruses
  • S. marcescens facilitates arboviral infection via a secreted protein named SmEnhancin
  • SmEnhancin digests gut membrane-bound mucins to enhance viral dissemination in mosquitoes
  • S. marcescens enhances the susceptibility of field mosquitoes to dengue virus



Mosquitoes are hematophagous vectors that can acquire human viruses in their intestinal tract. Here, we define a mosquito gut commensal bacterium that promotes permissiveness to arboviruses. Antibiotic depletion of gut bacteria impaired arboviral infection of a lab-adapted Aedes aegypti mosquito strain. Reconstitution of individual cultivable gut bacteria in antibiotic-treated mosquitoes identified Serratia marcescens as a commensal bacterium critical for efficient arboviral acquisition.S. marcescens facilitates arboviral infection through a secreted protein named SmEnhancin, which digests membrane-bound mucins on the mosquito gut epithelia, thereby enhancing viral dissemination. Field Aedes mosquitoes positive forS. marcescens were more permissive to dengue virus infection than those free of S. marcescens. Oral introduction ofS. marcescens into field mosquitoes that lack this bacterium rendered these mosquitoes highly susceptible to arboviruses. This study defines a commensal-driven mechanism that contributes to vector competence, and extends our understanding of multipartite interactions among hosts, the gut microbiome, and viruses.

Keywords: mosquito – microbiota  – arbovirus – Serratia marcescens – Enhancin

Keywords: Arbovirus; Mosquitoes; Aedes spp.; Serratia marcescens.


Averting the #postantibiotic era: successful use of #meropenem/vaborbactam for #carbapenem-resistant #Serratia marcescens and #Enterobacter aerogenes bacteraemia in a haemodialysis patient (J Antimicrob Chemother., abstract)

[Source: Journal of Antimicrobial Chemotherapy, full page: (LINK). Abstract, edited.]

Averting the post-antibiotic era: successful use of meropenem/vaborbactam for carbapenem-resistant Serratia marcescens and Enterobacter aerogenes bacteraemia in a haemodialysis patient

Sarah C J Jorgensen, Philip McDonald, Ryan P Mynatt, Jason M Pogue, Stephen A Lerner, Sorabh Dhar, Hossein Salimnia, Michael J Rybak

Journal of Antimicrobial Chemotherapy, dky346, https://doi.org/10.1093/jac/dky346

Published: 04 September 2018


The prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has increased dramatically over the past two decades, fuelling speculation that we are nearing the ‘post-antibiotic era’ and attesting to the critical need for novel antibiotics with activity against MDR pathogens.1 In 2015 the US FDA approved ceftazidime/avibactam for the treatment of complicated urinary tract infections (cUTIs) and complicated intra-abdominal infections caused by MDR Gram-negative bacteria.2 The introduction of ceftazidime/avibactam represented significant progress in the treatment of CRE, with accumulating real‐world data demonstrating improved efficacy and safety compared with older, more toxic antibiotics.3–5However, treatment failure rates as high as 30%–50% have been…



Issue Section: Research letter

© The Author(s) 2018. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Keywords: Antibiotics; Drugs Resistance; Carbapenem; Serratia marcescens; Enterobacter aerogenes; Bacteremia; Meropenem; Vaborbactam.