scholarly journals Comparative Genomics of Typical and Atypical Aeromonas salmonicida Complete Genomes Revealed New Insights into Pathogenesis Evolution

2022 ◽  
Vol 10 (1) ◽  
pp. 189
Author(s):  
Ignacio Vasquez ◽  
Ahmed Hossain ◽  
Hajarooba Gnanagobal ◽  
Katherinne Valderrama ◽  
Briony Campbell ◽  
...  

Aeromonas salmonicida is a global distributed Gram-negative teleost pathogen, affecting mainly salmonids in fresh and marine environments. A. salmonicida strains are classified as typical or atypical depending on their origin of isolation and phenotype. Five subspecies have been described, where A. salmonicida subsp. salmonicida is the only typical subspecies, and the subsp. achromogenes, masoucida, smithia, and pectinolytica are considered atypical. Genomic differences between A. salmonicida subsp. salmonicida isolates and their relationship with the current classification have not been explored. Here, we sequenced and compared the complete closed genomes of four virulent strains to elucidate their molecular diversity and pathogenic evolution using the more accurate genomic information so far. Phenotypes, biochemical, and enzymatic profiles were determined. PacBio and MiSeq sequencing platforms were utilized for genome sequencing. Comparative genomics showed that atypical strains belong to the subsp. salmonicida, with 99.55 ± 0.25% identity with each other, and are closely related to typical strains. The typical strain A. salmonicida J223 is closely related to typical strains, with 99.17% identity with the A. salmonicida A449. Genomic differences between atypical and typical strains are strictly related to insertion sequences (ISs) activity. The absence and presence of genes encoding for virulence factors, transcriptional regulators, and non-coding RNAs are the most significant differences between typical and atypical strains that affect their phenotypes. Plasmidome plays an important role in A. salmonicida virulence and genome plasticity. Here, we determined that typical strains harbor a larger number of plasmids and virulence-related genes that contribute to its acute virulence. In contrast, atypical strains harbor a single, large plasmid and a smaller number of virulence genes, reflected by their less acute virulence and chronic infection. The relationship between phenotype and A. salmonicida subspecies’ taxonomy is not evident. Comparative genomic analysis based on completed genomes revealed that the subspecies classification is more of a reflection of the ecological niche occupied by bacteria than their divergences at the genomic level except for their accessory genome.

2021 ◽  
Vol 9 (2) ◽  
pp. 348
Author(s):  
Florian Tagini ◽  
Trestan Pillonel ◽  
Claire Bertelli ◽  
Katia Jaton ◽  
Gilbert Greub

The Mycobacterium kansasii species comprises six subtypes that were recently classified into six closely related species; Mycobacterium kansasii (formerly M. kansasii subtype 1), Mycobacterium persicum (subtype 2), Mycobacterium pseudokansasii (subtype 3), Mycobacterium ostraviense (subtype 4), Mycobacterium innocens (subtype 5) and Mycobacterium attenuatum (subtype 6). Together with Mycobacterium gastri, they form the M. kansasii complex. M. kansasii is the most frequent and most pathogenic species of the complex. M. persicum is classically associated with diseases in immunosuppressed patients, and the other species are mostly colonizers, and are only very rarely reported in ill patients. Comparative genomics was used to assess the genetic determinants leading to the pathogenicity of members of the M. kansasii complex. The genomes of 51 isolates collected from patients with and without disease were sequenced and compared with 24 publicly available genomes. The pathogenicity of each isolate was determined based on the clinical records or public metadata. A comparative genomic analysis showed that all M. persicum, M. ostraviense, M innocens and M. gastri isolates lacked the ESX-1-associated EspACD locus that is thought to play a crucial role in the pathogenicity of M. tuberculosis and other non-tuberculous mycobacteria. Furthermore, M. kansasii was the only species exhibiting a 25-Kb-large genomic island encoding for 17 type-VII secretion system-associated proteins. Finally, a genome-wide association analysis revealed that two consecutive genes encoding a hemerythrin-like protein and a nitroreductase-like protein were significantly associated with pathogenicity. These two genes may be involved in the resistance to reactive oxygen and nitrogen species, a required mechanism for the intracellular survival of bacteria. Three non-pathogenic M. kansasii lacked these genes likely due to two distinct distributive conjugal transfers (DCTs) between M. attenuatum and M. kansasii, and one DCT between M. persicum and M. kansasii. To our knowledge, this is the first study linking DCT to reduced pathogenicity.


Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 298
Author(s):  
Despoina Konstantinou ◽  
Rafael V. Popin ◽  
David P. Fewer ◽  
Kaarina Sivonen ◽  
Spyros Gkelis

Sponges form symbiotic relationships with diverse and abundant microbial communities. Cyanobacteria are among the most important members of the microbial communities that are associated with sponges. Here, we performed a genus-wide comparative genomic analysis of the newly described marine benthic cyanobacterial genus Leptothoe (Synechococcales). We obtained draft genomes from Le. kymatousa TAU-MAC 1615 and Le. spongobia TAU-MAC 1115, isolated from marine sponges. We identified five additional Leptothoe genomes, host-associated or free-living, using a phylogenomic approach, and the comparison of all genomes showed that the sponge-associated strains display features of a symbiotic lifestyle. Le. kymatousa and Le. spongobia have undergone genome reduction; they harbored considerably fewer genes encoding for (i) cofactors, vitamins, prosthetic groups, pigments, proteins, and amino acid biosynthesis; (ii) DNA repair; (iii) antioxidant enzymes; and (iv) biosynthesis of capsular and extracellular polysaccharides. They have also lost several genes related to chemotaxis and motility. Eukaryotic-like proteins, such as ankyrin repeats, playing important roles in sponge-symbiont interactions, were identified in sponge-associated Leptothoe genomes. The sponge-associated Leptothoe stains harbored biosynthetic gene clusters encoding novel natural products despite genome reduction. Comparisons of the biosynthetic capacities of Leptothoe with chemically rich cyanobacteria revealed that Leptothoe is another promising marine cyanobacterium for the biosynthesis of novel natural products.


Author(s):  
Ziyi Liu ◽  
Ruifei Chen ◽  
Poshi Xu ◽  
Zhiqiang Wang ◽  
Ruichao Li

The spread of plasmid-mediated carbapenem-resistant clinical isolates is a serious threat to global health. In this study, an emerging NDM-encoding IncHI5-like plasmid from Klebsiella pneumoniae of infant patient origin was characterized, and the plasmid was compared to the available IncHI5-like plasmids to better understand the genetic composition and evolution of this emerging plasmid. Clinical isolate C39 was identified as K. pneumoniae and belonged to the ST37 and KL15 serotype. Whole genome sequencing (WGS) and analysis revealed that it harbored two plasmids, one of which was a large IncHI5-like plasmid pC39-334kb encoding a wide variety of antimicrobial resistance genes clustered in a single multidrug resistance (MDR) region. The blaNDM-1 gene was located on a ΔISAba125-blaNDM-1-bleMBL-trpF-dsbC structure. Comparative genomic analysis showed that it shared a similar backbone with four IncHI5-like plasmids and the IncHI5 plasmid pNDM-1-EC12, and these six plasmids differed from typical IncHI5 plasmids. The replication genes of IncHI5-like plasmids shared 97.06% (repHI5B) and 97.99% (repFIB-like) nucleotide identity with those of IncHI5 plasmids. Given that pNDM-1-EC12 and all IncHI5-like plasmids are closely related genetically, the occurrence of IncHI5-like plasmid is likely associated with the mutation of the replication genes of pNDM-1-EC12-like IncHI5 plasmids. All available IncHI5-like plasmids harbored 262 core genes encoding replication and maintenance functions and carried distinct MDR regions. Furthermore, 80% of them (4/5) were found in K. pneumoniae from Chinese nosocomial settings. To conclude, this study expands our knowledge of the evolution history of IncHI5-like plasmids, and more attention should be paid to track the evolution pathway of them among clinical, animal, and environmental settings.


2014 ◽  
Vol 80 (6) ◽  
pp. 2029-2037 ◽  
Author(s):  
Xin Lu ◽  
Weili Liang ◽  
Yunduan Wang ◽  
Jialiang Xu ◽  
Jun Zhu ◽  
...  

ABSTRACTVibrio fluvialisis an important food-borne pathogen that causes diarrheal illness and sometimes extraintestinal infections in humans. In this study, we sequenced the genome of a clinicalV. fluvialisstrain and determined its phylogenetic relationships with otherVibriospecies by comparative genomic analysis. We found that the closest relationship was betweenV. fluvialisandV. furnissii, followed by those withV. choleraeandV. mimicus. Moreover, based on genome comparisons and gene complementation experiments, we revealed genetic mechanisms of the biochemical tests that differentiateV. fluvialisfrom closely related species. Importantly, we identified a variety of genes encoding potential virulence factors, including multiple hemolysins, transcriptional regulators, and environmental survival and adaptation apparatuses, and the type VI secretion system, which is indicative of complex regulatory pathways modulating pathogenesis in this organism. The availability ofV. fluvialisgenome sequences may promote our understanding of pathogenic mechanisms for this emerging pathogen.


2019 ◽  
Vol 11 (7) ◽  
pp. 1959-1964 ◽  
Author(s):  
Jessica M Nelson ◽  
Duncan A Hauser ◽  
José A Gudiño ◽  
Yessenia A Guadalupe ◽  
John C Meeks ◽  
...  

Abstract Plant endosymbiosis with nitrogen-fixing cyanobacteria has independently evolved in diverse plant lineages, offering a unique window to study the evolution and genetics of plant–microbe interaction. However, very few complete genomes exist for plant cyanobionts, and therefore little is known about their genomic and functional diversity. Here, we present four complete genomes of cyanobacteria isolated from bryophytes. Nanopore long-read sequencing allowed us to obtain circular contigs for all the main chromosomes and most of the plasmids. We found that despite having a low 16S rRNA sequence divergence, the four isolates exhibit considerable genome reorganizations and variation in gene content. Furthermore, three of the four isolates possess genes encoding vanadium (V)-nitrogenase (vnf), which is uncommon among diazotrophs and has not been previously reported in plant cyanobionts. In two cases, the vnf genes were found on plasmids, implying possible plasmid-mediated horizontal gene transfers. Comparative genomic analysis of vnf-containing cyanobacteria further identified a conserved gene cluster. Many genes in this cluster have not been functionally characterized and would be promising candidates for future studies to elucidate V-nitrogenase function and regulation.


2021 ◽  
Author(s):  
Hualin Liu ◽  
Bingyue Xin ◽  
Jinshui Zheng ◽  
Hao Zhong ◽  
Yun Yu ◽  
...  

Abstract More and more frequently, genomics and comparative genomics have been used as routine methods for general microbiological research. However, using several tools or even writing some scripts are required for completing a simple analysis, which is complicated for most biological researchers. To simplify the operation process, particularly for the convenience of microbiologists, here we have developed PGCGAP, a comprehensive, malleable, and easily installed prokaryotic genomic and comparative genomic analysis pipeline. PGCGAP implements genome assembly, gene prediction and annotation, genome and metagenome distance estimation, phylogenetic analysis, COG annotation, pan-genome analysis, inference of orthologous gene groups, variant calling and annotation, and screening for antimicrobial and virulence genes. Although we have tried our best to simplify the installation and usage of PGCGAP, it may be difficult for non-bioinformaticians to master it. Therefore, a protocol was created to help microbiologists without any experience in bioinformatics to establish their bioinformatics platform and perform routine analyses. This protocol shows how to choose the equipment to install a Linux subsystem on a laptop with a Windows 10 system, to install the PGCGAP and perform all analyses with an example dataset. The protocol requires a basic understanding of Linux, so an additional web page was written to help uninitiated users learn Linux and whole-genome sequencing (https://github.com/liaochenlanruo/pgcgap/wiki/Learning-bioinformatics or http://bcam.hzau.edu.cn/linuxwgs.php).


2019 ◽  
Author(s):  
Shengyi Han ◽  
JianHua Zhou ◽  
Lina Ma ◽  
Chengxiu Ma ◽  
Qiaoying Zeng ◽  
...  

Abstract Background: Enterococcus are important opportunistic pathogens that readily acquire foreign genes and could be easily lysogenized by phages. But no comparative genomic analysis of Enterococcus prophages had been undertaken to date. The prophage distribution, potential contribution and the relationship with Enterococcus defensive system remain unclear. Result: This study presents a comparative analysis of 563 putative prophages identified in 107 chromosomes and 301 plasmids of Enterococcus. Our result suggested that lysogens are highly prevalent in Enterococcus and Enterococcus genomes have more prophages than other bacteria, the number of prophages are related with strains pathogenicity, groups and isolated regions, and the prophages distribution present phylogeographic pattern. By analyzing the prophages characteristic, it is found that prophages can be divided into many clusters, but most of prophages have distant genetic relationship with sequenced phages and remain unreported; Prophages integrated into chromosomes and plasmids have different evolutionary origins, and show different genomes size, GC% and genes characteristic. It should be noted that all antibiotic resistance genes are carried by plasmids prophages and E. faecium plasmid prophages play important roles in transmission of vancomycin resistance genes through plasmid conjugation transfer and phages transduction. By investigating and statistical analyzing the relationship between major defend systems and the number of prophages, it indicated that R-M system often absent in Enterococcus, orphan CRISPR array prevalent in most of Enterococcus, and the presence of CRISPR-spacers and the absence of prophages in lysogen is inversely related. Conclusion: To our knowledge, this is the first systematic analysis of Enterococcus prophages distribution, potential contribution and phylogeny, and elucidate the relationship between defense system and lysogeny in Enterococcus. This information helps to understand how prophages affect its hosts diversity, fitness and evolution.


Diversity ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 204
Author(s):  
Dominik Rutz ◽  
David Frasson ◽  
Martin Sievers ◽  
Jochen Blom ◽  
Fabio Rezzonico ◽  
...  

In recent years, the use of whole-cell biocatalysts and biocatalytic enzymes in biotechnological applications originating from the genus Pseudomonas has greatly increased. In 2014, two new species within the Pseudomonas putida group were isolated from Swiss forest soil. In this study, the high quality draft genome sequences of Pseudomonas wadenswilerensis CCOS 864T and Pseudomonas reidholzensis CCOS 865T were used in a comparative genomics approach to identify genomic features that either differed between these two new species or to selected members of the P. putida group. The genomes of P. wadenswilerensis CCOS 864T and P. reidholzensis CCOS 865T were found to share genomic features for the degradation of aromatic compounds or the synthesis of secondary metabolites. In particular, genes encoding for biocatalytic relevant enzymes belonging to the class of oxidoreductases, proteases and isomerases were found, that could yield potential applications in biotechnology. Ecologically relevant features revealed that both species are probably playing an important role in the degradation of soil organic material, the accumulation of phosphate and biocontrol against plant pathogens.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S295-S295
Author(s):  
Hoan J Lee ◽  
Joon Kee Lee ◽  
Yun Young Choi ◽  
Ji Young Park ◽  
Moon-Woo Seong ◽  
...  

Abstract Background This study applied high-throughput whole-genome sequencing (WGS) technologies to investigate the comparative genomics of 30 M. pneumoniae strains isolated from children with pneumonia in South Korea during two epidemics from 2010 to 2016 in comparison with a global collection of 48 Mycoplasma pneumoniae strains which includes seven countries ranging from 1944 to 2017. Methods A total number of 30 M. pneumoniae strains were selected for whole-genome sequence analysis from two epidemics, 2010–2012 and 2014–2016. Next-generation sequencing (NGS) of all M. pneumoniae strains was performed using the Illumina MiSeq desktop sequencer. Comparative genomic analysis was performed using BLAST Ring Image Generator (BRIG), MAUVE, MAFFT, CLC Phylogeny Module, SnpEff, and Pathosystems Resource Integration Center (PATRIC). Results The 30 Korean strains had approximately 40% GC content and ranged from 815,686 to 818,669 base pairs, coding for a total of 809 to 828 genes. Overall, BRIG revealed 99% to>99% similarity among strains. The genomic similarity dropped to approximately 95% in the P1 type 2 strains when aligned to the reference M129 genome, which corresponded to the region of the p1 gene. MAUVE detected four subtype-specific of which were all hypothetical proteins except for one tRNA insertion in all P1 type 1 strains. eBURST analysis demonstrated two clonal complexes which are accordant with the known P1 typing, with higher diversity among P1 type 2 strains. The phylogenetic tree constructed with 78 genomes including 48 genomes outside Korea, formed three clusters, in which the sequence type 3 strains from Korea were divided into two P1 type 1 clusters. Conclusion The comparative genomics of the 78 M. pneumoniae strains including 30 strains from Korea by WGS reveals structural diversity and phylogenetic associations, even though the similarity across the strains was very high. Disclosures All authors: No reported disclosures.


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