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Introduction
Publications
Publications (108)
Plasmids that carry antibiotic resistance genes occur frequently in Aeromonas salmonicida subsp. salmonicida, an aquatic pathogen with severe consequences in salmonid farming. Here, we describe a 67 kb plasmid found in the A. salmonicida subsp. salmonicida Strain SHY15-2939 from Quebec, Canada. This new plasmid, named pAsa-2939 and identified by hi...
In addition to be an important zoonotic agent, Streptococcus suis serotype 2 causes severe infections in pigs. In this study, we characterized a new bacteriocin produced by Streptococcus pluranimalium 2N12 isolated from a pig nasal sample. The bacteriocin, termed pluranimalicin 2N12, was a two-peptide class IIb bacteriocin active against S. suis. T...
Actinobacillus pleuropneumoniae is the causal agent of porcine pleuropneumonia, a highly contagious and often deadly respiratory disease that causes major economic losses in the swine industry worldwide. The aim of the present study was to investigate the hydrogen peroxide (H2O2)-dependent antagonistic activity of Streptococcus pluranimalium 2N12 (...
The genome sequencing of Aeromonas salmonicida subspecies salmonicida strain 2004-072 revealed a plasmid bearing a region carrying antibiotic resistance genes very similar to the one found in the plasmid pRAS1, an IncU family plasmid. This new plasmid was named pRAS1b.
The type three secretion system (TTSS) locus of Aeromonas salmonicida subsp. salmonicida, located on the plasmid pAsa5, is known to be lost when the bacterium is grown at temperatures of 25 °C. The loss of the locus is due to the recombination of the insertion sequences flanking the TTSS region. However, the mechanism involved in this recombination...
The yeast Geotrichum candidum (teleomorph Galactomyces candidus) is inoculated onto mold- and smear-ripened cheeses and plays several roles during cheese ripening. Its ability to metabolize proteins, lipids, and organic acids enables its growth on the cheese surface and promotes the development of organoleptic properties. Recent multilocus sequence...
The Gram-negative bacterium Aeromonas salmonicida subsp. salmonicida is an aquatic pathogen which causes furunculosis to salmonids, especially in fish farms. The emergence of strains of this bacterium exhibiting antibiotic resistance is increasing, limiting the effectiveness of antibiotherapy as a treatment against this worldwide disease. In the pr...
The Gram-positive α-hemolytic Streptococcus suis is a major pathogen in the swine industry and an emerging zoonotic agent that can cause several systemic issues in both pigs and humans. A total of 35 S. suis serotypes (SS) have been identified and genotyped into > 700 sequence types (ST) by multilocus sequence typing (MLST). Eurasian ST1 isolates a...
Physical map of Streptococcus suis 90–1330.
(A)
S. suis 90–1330 chromosome. Genes located on the forward strand are indicated by orange boxes whereas those located on the minus strand are highlighted in yellow. Methylation patterns and GC-skew distribution are indicated in the outer and inner rings, respectively. GC-skew patterns (positive and nega...
Predicted transposable elements in S. suis 90–1330.
Transposable elements listed in S1 Table were derived from the NCBI PGAP annotations.
(XLSX)
Orthologs between the S. suis 90–1330 putative ICE and ICESsuCZ130302.
Orthologs were inferred by BLASTP searches (E-value cutoff: 1e-10). Genes from Lebel et al. [4] are highlighted in magenta (sslA; bacteriocin). ICE-related genes identified by TXSScan/CONJscan searches and by Tn5252 BLASTP homology searches are highlighted in blue.
(XLSX)
Structural comparison between the S. suis 90–1330 putative ICE and ICESsuCZ130302 from S. suis CZ130302.
Conserved blocks of genes arrayed in the same order between the two loci are highlighted by alternating colors. Locus tags are derived from accession numbers NZ_CP012731.1 (S. suis 90–1330) and NZ_CP024974.1 (S. suis CZ130302).
(PDF)
Putative prophages in the S. suis 90–1330 genomes.
This file is the raw output from PHASTER.
(TXT)
ICE proteins identified in the S. suis 90–1330 putative ICE by CONJscan/TXSScan searches.
CONJscan/TXSScan searches were performed with MacSyFinder 1.05. Duplicate hits with lower E-values are grayed out.
(XLSX)
Detection of the circular form of the S. suis 90–1330 ICE.
(A) Diagram of the chromosomic region contiguous to the ICE integration site. The ICESa2603-like direct repeats are represented by yellow boxes. The orientation of the primers used to detect the integrated and circular forms are indicated by thin arrows (see Material and Methods for the pri...
S. suis strains used in this study.
Predicted serotypes are based on BLASTN searches using the cps genes from Liu et al. [67] against the S. suis accession numbers.
(XLSX)
S. suis 90–1330 repeat regions.
Repeated loci were identified with RepeatFinder as implemented in Geneious R9.1.7.
(XLSX)
Distribution of the S. suis 90–1330 KEGG metabolic pathways.
KEGG metabolic pathways and enzyme commission (EC) numbers were assigned with BlastKOALA.
(XLSX)
ComRS competence components in S. suis 90–1330.
ComRS proteins and promoters were identified by BLAST searches of known orthologous streptococcal sequences against the S. suis 90–1330 genome.
(XLSX)
Putative virulence factor homologs in S. suis 90–1330.
The virulence factors discussed in Segura et al. [36] were searched against the S. suis 90–1330 genome using BLAST searches. Genes potentially important in virulence are highlighted in orange; pseudogenes are grayed out.
(XLSX)
Putative additional virulence factors in S. suis 90–1330 derived from homology searches against the core dataset of the Virulence Factor Database (VFDB).
S. suis proteins displaying homology with putative VFDB virulence factors (E-value cutoff: 1e-10) are listed here.
(XLSX)
In Aeromonas salmonicida subsp. salmonicida, a bacterium that causes fish disease, there are two types of small plasmids (<15 kbp): plasmids without known function, called cryptic plasmids, and plasmids that bear beneficial genes for the bacterium. Four among them are frequently detected in strains of A. salmonicida subsp. salmonicida: pAsa1, pAsa2...
Background:
Aeromonas salmonicida subsp. salmonicida is a ubiquitous psychrophilic waterborne bacterium and a fish pathogen. The numerous mobile elements, especially insertion sequences (IS), in its genome promote rearrangements that impact its phenotype. One of the main virulence factors of this bacterium, its type three secretion system (TTSS),...
CRISPR (clustered regularly interspaced short palindromic repeats)-Cas systems have been adapted into a powerful genome-editing tool. The basis for the flexibility of the tool lies in the adaptive nature of CRISPR-Cas as a bacterial immune system. Here, we describe a protocol to experimentally demonstrate the adaptive nature of this bacterial immun...
CRISPR–Cas is an adaptive immune system found in Bacteria and Archaea that confers sequence-specific protection against invasion by foreign nucleic acids. CRISPR–Cas is also a powerful tool for microbiology education and has been an inspiring model for our students for the past three years.
Aeromonas salmonicida subsp. salmonicida , the causative agent of furunculosis in salmonids, is an issue especially because many isolates of this bacterium display antibiotic resistances, which limit treatments against the disease. Recent results suggested the possible existence of alternative forms of pAsa4, a large plasmid found in A. salmonicida...
Aeromonas salmonicida subsp. salmonicida , the causative agent of furunculosis in salmonids, is an issue especially because many isolates of this bacterium display antibiotic resistances, which limit treatments against the disease. Recent results suggested the possible existence of alternative forms of pAsa4, a large plasmid found in A. salmonicida...
Aeromonas salmonicida subsp. salmonicida , the causative agent of furunculosis in salmonids, is an issue especially because many isolates of this bacterium display antibiotic resistances, which limit treatments against the disease. Recent results suggested the possible existence of alternative forms of pAsa4, a large plasmid found in A. salmonicida...
Aeromonas salmonicida subsp. salmonicida is a fish pathogen known to have a rich plasmidome. In the present study, we discovered an isolate of this bacterium bearing an additional unidentified small plasmid. After having sequenced the DNA of that isolate by next-generation sequencing, it appeared that the new small plasmid is a ColE1-type replicon...
Recently, we reported the purification and characterization of three distinct lantibiotics (named suicin 90-1330, suicin 3908, and suicin 65) produced by Streptococcus suis. In this study, we investigated the distribution of the three suicin lantibiotic gene clusters among serotype 2 S. suis strains belonging to sequence type (ST) 25 and ST28, the...
Bacteriocins are antimicrobial peptides of bacterial origin that are considered as a promising alternative to the use of conventional antibiotics. Recently, our laboratory reported the purification and characterization of two lantibiotics, suicin 90-1330 and suicin 3908, produced by the swine pathogen and zoonotic agent Streptococcus suis (serotype...
While Streptococcus suis serotype 2 is known to cause severe infections in pigs, it can also be isolated from the tonsils of healthy animals that do not develop infections. We hypothesized that S. suis strains in healthy carrier pigs may have the ability to produce bacteriocins, which may contribute to preventing infections by pathogenic S. suis st...
The bacterium Aeromonas salmonicida is the etiological agent of furunculosis, a widespread fish disease causing important economic losses to the fish farming industry. Antibiotic treatments in fish farms may be challenging given the existence of multidrug-resistant isolates of this bacterium. Here, we report the draft genome sequences of the 2004-0...
The ubiquitous water-borne Gram-negative bacterium Aeromonas salmonicida subsp. salmonicida is the causative agent of furunculosis, a worldwide disease in fish farms. Plasmids carrying antibiotic resistance genes
have already been described for this bacterium. The aim of the present study was to identify and characterize additional multidrug
resist...
Aeromonas salmonicida subsp. salmonicida is the etiologic agent of furunculosis, a disease affecting fish of the salmonid family. This disease has important deleterious effects worldwide and it is even more problematic in the Province of Qubec (Canada) where about 95% of the fish farming is devoted to salmonids. This situation is urging us to gain...
Streptococcus suis serotype 2 is known to cause severe infections (meningitis, endocarditis, septicaemia) in pigs, and is considered an emerging zoonotic agent. Antibiotics have long been used in the swine industry for disease treatment/prevention and growth promoters. This pattern of utilization resulted in the spread of antibiotic resistance in S...
Aeromonas salmonicida subsp. salmonicida is a major fish pathogen. Molecular tools are required to study the virulence and genomic stability of this bacterium. An efficient electroporation-mediated transformation protocol for Aeromonas salmonicida subsp. salmonicida would make genetic studies faster and easier. In the present study, we designed the...
Streptococcus suis serotype 2 is known to cause severe infections in pigs, including meningitis, endocarditis and pneumonia. Furthermore, this bacterium is considered an emerging zoonotic agent. Recently, increased antibiotic resistance in S. suis has been reported worldwide. The objective of this study was to evaluate the potential of nisin, a bac...
The genome of the fish pathogen Aeromonas salmonicida subsp salmonicida harbors a large number of insertion sequences (ISs), many of which are located on plasmids. In the present study, we analyzed the small plasmid profile of A. salmonicida strains to identify evidences of plasmid alterations. Ten out of 78 strains analyzed displayed an unconventi...
Streptococcus suis is a major swine pathogen and an emerging zoonotic agent. The ability of pathogenic bacteria to bind the complement regulator factor H on their cell surface may allow them to avoid complement attack and phagocytosis. The aim of this study was to characterize a new cell surface protein possessing factor H-binding activity in S. su...
The introduction of multilocus sequence typing (MLST) for strain characterization provided the first sequence-based approach for genotyping many fungi, leading to reproducible, reliable, and exchangeable data. A MLST scheme based on the analysis of six housekeeping genes was developed for genotyping Geotrichum candidum. The scheme was first develop...
Insertion sequences (IS) are abundant in the bacterial fish pathogen Aeromonas salmonicida genome. IS are involved in rearrangement events that lead to the loss of virulence. In previous work, we studied a plasmid rearrangement that causes the deletion of the type three secretion system in A. salmonicida, resulting in a loss of virulence. We showed...
Aeromonas salmonicida, a bacterial fish pathogen, possesses a functional Type Three Secretion System (TTSS), which is essential for its virulence. The genes for this system are mainly located in a single region of the large pAsa5 plasmid. Bacteria lose the TTSS region from this plasmid through rearrangements when grown in stressful growth condition...
The dimorphic yeast Geotrichum candidum (teleomorph: Galactomyces candidus) is commonly used to inoculate washed-rind and bloomy-rind cheeses. However, little is known about the phylogenetic lineage of this microorganism. We have sequenced the complete 18S, 5.8S, 26S ribosomal RNA genes and their internal transcribed spacers (ITS1) and ITS2 regions...
Streptococcus suis is a major swine pathogen that is responsible for severe infections such as meningitis, endocarditis, and septicemia. S. suis is also recognized as a zoonotic agent and expresses several virulence factors. The recently identified subtilisin-like protease (SspA) of S. suis plays an important role in the pathogenicity of this bacte...
Twenty-four mutacin-producing Streptococcus mutans strains were screened for their propensity to produce class II one-peptide bacteriocin using a deferred antagonism assay. Streptococcus salivarius and 3 mutants defective in their mannose phosphotransferase systems (mannose-PTS) were used as sensitive strains to identify which mannose-PTS could act...
Streptococcus suis is a major swine pathogen and zoonotic agent that mainly causes septicemia, meningitis, and endocarditis. It has recently been suggested that proteinases produced by S. suis (serotype 2) are potential virulence determinants. In the present study, we screened a S. suis mutant library created by the insertion of Tn917 transposon in...
Streptococci are divided into six phylogenetic groups, i.e, anginosus, bovis, mitis, mutans, pyogenic, and salivarius, with the salivarius group consisting of only three distinct species. Two of these species, Streptococcus salivarius and Streptococcus vestibularis, are members of the normal human oral microflora whereas the third, Streptococcus th...
Streptococcus thermophilus is unable to metabolize the galactose moiety of lactose. In this paper, we show that a transformant of S. thermophilus SMQ-301 expressing Streptococcus salivarius galK and galM was able to grow on galactose and expelled at least twofold less galactose into the medium during growth on lactose.
The virulent cos-type Streptococcus thermophilus phage DT1 was previously isolated from a mozzarella whey sample, and its complete genomic sequence is available. The putative
ori of phage DT1 is characterized by three inverted and two direct repeats located in a noncoding region between orf36 and orf37. As the replication ability of the putative or...
In Streptococcus thermophilus, lactose is taken up by LacS, a transporter that comprises a membrane translocator domain and a hydrophilic regulatory domain
homologous to the IIA proteins and protein domains of the phosphoenolpyruvate:sugar phosphotransferase system (PTS). The IIA
domain of LacS (IIALacS) possesses a histidine residue that can be ph...
We investigated the involvement of oral epithelial cells via two cytokines (IL-6 and TNF-alpha) and one chemokine (IL-8) in local defences against live yeast (Candida albicans) and bacteria (Streptococcus salivarius) using an engineered human oral mucosa model. We report that the yeast changed from the blastospore to the hyphal form and induced sig...
The lactic acid bacterium Streptococcus thermophilus is widely used by the dairy industry for its ability to transform lactose, the primary sugar found in milk, into lactic acid.
Unlike the phylogenetically related species Streptococcus salivarius, S. thermophilus is unable to metabolize and grow on galactose and thus releases substantial amounts o...
Plasmids of Streptococcus thermophilus were previously classified, based on DNA homology, into at least four groups (A-D). Here, we report the characterization of plasmids of group B and D. The sequence analysis of pSMQ173b (group D) indicates that this plasmid contains 4449 bp, five open reading frames (ORFs) and replicates via the rolling-circle...
A Tn917 mutant library was generated to identify genes involved in the biogenesis of Streptococcus salivarius fimbriae. A fimbria-deficient mutant was isolated by negative selection using an immunomagnetic separation technique with specific anti-fimbriae polyclonal antibodies (pAbs). The transposon was inserted in an ORF, called orf176, which encod...
The oral bacterium Streptococcus salivarius takes up lactose via a transporter called LacS that shares 95% identity with the LacS from Streptococcus thermophilus, a phylogenetically closely related organism. S. thermophilus releases galactose into the medium during growth on lactose. Expulsion of galactose is mediated via LacS and stimulated by
pho...
Streptococcus salivarius is divided into two serological subgroups that carry either fibrils or fimbriae. Although fimbriae have been observed on up to 50% of S. salivarius strains in the human oral cavity, no function has yet been assigned to them. To determine whether S. salivarius fimbriae have a role in adhesion, we examined the ability of S. s...
In most streptococci, glucose is transported by the phosphoenolpyruvate (PEP):glucose/mannose phosphotransferase system (PTS)
via HPr and IIABMan, two proteins involved in regulatory mechanisms. While most strains of Streptococcus thermophilus do not or poorly metabolize glucose, compelling evidence suggests that S. thermophilus possesses the genes...
Phosphorylation of HPr, the small phosphocarrier protein of the phosphoenolpyruvate:sugar phosphotransferase system, on Ser46 by the HPr(Ser) kinase (HPrK/P) is a vital step in catabolite repression in Gram-positive bacteria. Streptococcus salivarius HPrK/P is reported to be a multimeric protein not regulated by metabolic intermediates. We re-evalu...
Phosphorylation of HPr, the small phosphocarrier protein of the phosphoenolpyruvate:sugar phosphotransferase system, on Ser46 by the HPr(Ser) kinase (HPrK/P) is a vital step in catabolite repression in Gram-positive bacteria. Streptococcus salivarius HPrK/P is reported to be a multimeric protein not regulated by metabolic intermediates. We re-evalu...
Xylitol is transported by Streptococcus mutans via a constitutive phosphoenolpyruvate:fructose phosphotransferase system (PTS) composed of a IIABC protein. Spontaneous xylitol-resistant strains are depleted in constitutive fructose-PTS activity, exhibit additional phenotypes, and are associated with the caries-preventive properties of xylitol. Poly...
Xylitol is transported by Streptococcus mutans via a constitutive phosphoenolpyruvate:fructose phosphotransferase system (PTS) composed of a IIABC protein. Spontaneous xylitol-resistant strains are depleted in constitutive fructose-PTS activity, exhibit additional phenotypes, and are associated with the caries-preventive properties of xylitol. Poly...
Streptococcus salivarius is a lactose- and galactose-positive bacterium that is phylogenetically closely related to Streptococcus thermophilus, a bacterium that metabolizes lactose but not galactose. In this paper, we report a comparative characterization of the S. salivarius and S. thermophilus gal-lac gene clusters. The clusters have the same org...
