-
BMC Veterinary Research Oct 2023Streptococcus suis (S. suis) is a major pig pathogen worldwide with zoonotic potential. Though different research groups have contributed to a better understanding of... (Review)
Review
Streptococcus suis (S. suis) is a major pig pathogen worldwide with zoonotic potential. Though different research groups have contributed to a better understanding of the pathogenesis of S. suis infections in recent years, there are still numerous neglected research topics requiring animal infection trials. Of note, animal experiments are crucial to develop a cross-protective vaccine which is highly needed in the field. Due to the severe clinical signs associated with S. suis pathologies such as meningitis and arthritis, implementation of refinement is very important to reduce pain and distress of experimentally infected pigs. This review highlights the great diversity of clinical signs and courses of disease after experimental S. suis pig infections. We review clinical read out parameters and refinement strategies in experimental S. suis pig infections published between 2000 and 2021. Currently, substantial differences exist in describing clinical monitoring and humane endpoints. Most of the reviewed studies set the body temperature threshold of fever as high as 40.5°C. Monitoring intervals vary mainly between daily, twice a day and three times a day. Only a few studies apply scoring systems. Published scoring systems are inconsistent in their inclusion of parameters such as body temperature, feeding behavior, and respiratory signs. Locomotion and central nervous system signs are more common clinical scoring parameters in different studies by various research groups. As the heterogenicity in clinical monitoring limits the comparability between studies we hope to initiate a discussion with this review leading to an agreement on clinical read out parameters and monitoring intervals among S. suis research groups.
Topics: Animals; Swine; Streptococcus suis; Swine Diseases; Body Temperature; Streptococcal Infections
PubMed: 37798634
DOI: 10.1186/s12917-023-03735-9 -
Vaccines May 2024() is a Gram-positive bacterium that causes substantial disease in pigs. is also an emerging zoonoses in humans, primarily in Asia, through the consumption of...
() is a Gram-positive bacterium that causes substantial disease in pigs. is also an emerging zoonoses in humans, primarily in Asia, through the consumption of undercooked pork and the handling of infected pig meat as well as carcasses. The complexity of epidemiology, characterized by the presence of multiple bacterial serotypes and strains with diverse sequence types, identifies a critical need for a universal vaccine with the ability to confer cross-protective immunity. Highly conserved immunogenic proteins are generally considered good candidate antigens for subunit universal vaccines. In this study, the cross-protection of the sugar ABC transporter substrate-binding protein (S-ABC), a surface-associated immunogenic protein of , was examined in mice for evaluation as a universal vaccine candidate. S-ABC was shown to be highly conserved, with 97% amino acid sequence identity across 31 strains deposited in GenBank. Recombinantly expressed S-ABC (rS-ABC) was recognized via rabbit sera specific to serotype 2. The immunization of mice with rS-ABC induced antigen-specific antibody responses, as well as IFN-γ and IL-4, in multiple organs, including the lungs. rS-ABC immunization conferred high (87.5% and 100%) protection against challenges with serotypes 2 and 9, demonstrating high cross-protection against these serotypes. Protection, albeit lower (50%), was also observed in mice challenged with serotype 7. These data identify S-ABC as a promising antigenic target within a universal subunit vaccine against .
PubMed: 38793795
DOI: 10.3390/vaccines12050544 -
Journal of Applied Microbiology Sep 2023Streptococcus suis seriously harms people and animals, and importantly, causes great economic losses in the pig industry. Similar to most Gram-positive pathogenic...
AIMS
Streptococcus suis seriously harms people and animals, and importantly, causes great economic losses in the pig industry. Similar to most Gram-positive pathogenic bacteria, sortase A (SrtA) of S. suis can mediate the anchoring of a variety of virulence factors that contain specific sorting sequences to the surface of the bacterial cell wall envelope and participate in pathogenicity. The purpose of this study is to clarify the molecular mechanism of epigallocatechin-3-gallate (EGCG) inhibiting S. suis SrtA and provide more evidence for the development of novel anti-S. suis infections drugs.
METHODS AND RESULTS
Through the SrtA substrate cleavage experiment, we found that the main component of green tea, EGCG, can effectively inhibit the enzyme activity of S. suis SrtA. Further, molecular docking and molecular dynamics simulation were used to clarify the molecular mechanism of its inhibitory effect, demonstrating that EGCG mainly interacts with amino acids at 113 and 115 to exert its inhibitory function. It was previously found that EGCG can inhibit the growth of S. suis and reduce the activity of suilysin and inhibit its expression. Our research reveals a new function of EGCG in S. suis infection.
CONCLUSIONS
Our research proves that EGCG can effectively inhibit the transpeptidase activity of SrtA. We also clarify the accompanying molecular mechanism, providing more sufficient evidence for the use of EGCG as a potential lead compound against S. suis infection.
Topics: Animals; Swine; Molecular Docking Simulation; Streptococcus suis; Bacterial Proteins
PubMed: 37634082
DOI: 10.1093/jambio/lxad191 -
Emerging Microbes & Infections Dec 2024is a significant and emerging zoonotic pathogen. ST1 and ST7 strains are the primary agents responsible for human infections in China, including the Guangxi Zhuang...
is a significant and emerging zoonotic pathogen. ST1 and ST7 strains are the primary agents responsible for human infections in China, including the Guangxi Zhuang Autonomous Region (GX). To enhance our understanding of ST1 population characteristics, we conducted an investigation into the phylogenetic structure, genomic features, and virulence levels of 73 ST1 human strains from GX between 2005 and 2020. The ST1 GX strains were categorized into three lineages in phylogenetic analysis. Sub-lineage 3-1a exhibited a closer phylogenetic relationship with the ST7 epidemic strain SC84. The strains from lineage 3 predominantly harboured 89K-like pathogenicity islands (PAIs) which were categorized into four clades based on sequence alignment. The acquirement of 89K-like PAIs increased the antibiotic resistance and pathogenicity of corresponding transconjugants. We observed significant diversity in virulence levels among the 37 representative ST1 GX strains, that were classified as follows: epidemic (E)/highly virulent (HV) (32.4%, 12/37), virulent plus (V+) (29.7%, 11/37), virulent (V) (18.9%, 7/37), and lowly virulent (LV) (18.9%, 7/37) strains based on survival curves and mortality rates at different time points in C57BL/6 mice following infection. The E/HV strains were characterized by the overproduction of tumour necrosis factor (TNF)-α in serum and promptly established infection at the early phase of infection. Our research offers novel insights into the population structure, evolution, genomic features, and pathogenicity of ST1 strains. Our data also indicates the importance of establishing a scheme for characterizing and subtyping the virulence levels of strains.
Topics: Streptococcus suis; Streptococcal Infections; China; Humans; Phylogeny; Virulence; Animals; Mice; Genome, Bacterial; Genomic Islands; Female; Genomics; Virulence Factors
PubMed: 38578304
DOI: 10.1080/22221751.2024.2339946 -
Frontiers in Cellular and Infection... 2023is a major pathogen for swine and human. Here we aimed to know the rates of antimicrobial resistance (AMR) in invasive isolates recovered along Spain between 2016 -...
INTRODUCTION
is a major pathogen for swine and human. Here we aimed to know the rates of antimicrobial resistance (AMR) in invasive isolates recovered along Spain between 2016 - 2021 and elucidate their genetic origin.
METHODS
Antibiotic susceptibility testing was performed for 116 isolates of different genetic backgrounds and geographic origins against 18 antibiotics of 9 families. The association between AMR and genotypes and the origin of the isolates were statistically analyzed using Pearson´s chi-square test and the likelihood ratio. The antimicrobial resistant genes were identified by whole genome sequencing analysis and PCR screenings.
RESULTS
High AMR rates (>80%) were detected for tetracyclines, spectinomycin, lincosamides, and marbofloxacin, medium (20-40%) for sulphonamides/trimethoprim, tiamulin, penicillin G, and enrofloxacin, and low (< 20%) for florfenicol, and four additional β-lactams. The occurrence of multidrug resistance was observed in 90% of isolates. For certain antibiotics (penicillin G, enrofloxacin, marbofloxacin, tilmicosin, and erythromycin), AMR was significantly associated with particular sequence types (STs), geographic regions, age of pigs, and time course. Whole genome sequencing comparisons and PCR screenings identified 23 AMR genes, of which 19 were previously reported in ((3')-IIIa, , aac(6')-Ie-(2'')-Ia, (B), (A/E), (D), (C), (B), (E), (F), (M), (O), (O/W/32/O), (W)), and 4 were novel ((2'')-IIIa, (47), (T)). These AMR genes explained the AMR to spectinomycin, macrolides, lincosamides, tiamulin, and tetracyclines. Several genes were located on mobile genetic elements which showed a variable organization and composition. As AMR gene homologs were identified in many human and animal pathogens, the resistome of has a different phylogenetic origin. Moreover, AMR to penicillin G, fluoroquinolones, and trimethoprim related to mutations in genes coding for target enzymes (, , and . Bioinformatic analysis estimated traits of recombination on target genes, also indicative of gene transfer events.
CONCLUSIONS
Our work evidences that is a major contributor to AMR dissemination across veterinary and human pathogens. Therefore, control of AMR in should be considered from a One Health approach in regions with high pig production to properly tackle the issue of antimicrobial drug resistance.
Topics: Animals; Swine; Humans; Streptococcus suis; Spectinomycin; Enrofloxacin; Spain; Phylogeny; Streptococcal Infections; Anti-Bacterial Agents; Anti-Infective Agents; Lincosamides; Penicillin G; Trimethoprim; Tetracyclines; Microbial Sensitivity Tests; Drug Resistance, Bacterial; Diterpenes
PubMed: 38317790
DOI: 10.3389/fcimb.2023.1329632 -
Virulence Dec 2024(), a significant zoonotic bacterial pathogen impacting swine and human, is associated with severe systemic diseases such as streptococcal toxic shock-like syndrome,...
(), a significant zoonotic bacterial pathogen impacting swine and human, is associated with severe systemic diseases such as streptococcal toxic shock-like syndrome, meningitis, septicaemia, and abrupt fatality. The multifaceted roles of complement components C5a and C3a extend to orchestrating inflammatory cells recruitment, oxidative burst induction, and cytokines release. Despite the pivotal role of subtilisin-like serine proteases in pathogenicity, their involvement in immune evasion remains underexplored. In the present study, we identify two cell wall-anchored subtilisin-like serine proteases in , SspA-1 and SspA-2, as binding partners for C3a and C5a. Through Co-Immunoprecipitation, Enzyme-Linked Immunosorbent and Far-Western Blotting Assays, we validate their interactions with the aforementioned components. However, SspA-1 and SspA-2 have no cleavage activity against complement C3a and C5a performed by Cleavage assay. Chemotaxis assays reveal that recombinant SspA-1 and SspA-2 effectively attenuate monocyte chemotaxis towards C3a and C5a. Notably, the , and mutant strains exhibit compromised survival in blood, and resistance of opsonophagocytosis, alongside impaired survival in blood and colonization compared to the parental strain SC-19. Critical insights from the murine and larva infection models further underscore the significance of in altering mortality rates. Collectively, our findings indicate that SspA-1 and SspA-2 are novel binding proteins for C3a and C5a, thereby shedding light on their pivotal roles in immune evasion and the pathogenesis.
Topics: Animals; Humans; Swine; Mice; Immune Evasion; Complement C3a; Streptococcus suis; Cytokines; Subtilisins; Streptococcal Infections
PubMed: 38170683
DOI: 10.1080/21505594.2023.2301246 -
Heliyon Mar 2024is a bacterial gram-positive pathogen that causes invasive infections in swine and is also a zoonotic disease agent. Traditional molecular typing techniques such as... (Review)
Review
is a bacterial gram-positive pathogen that causes invasive infections in swine and is also a zoonotic disease agent. Traditional molecular typing techniques such as ribotyping, multilocus sequence typing, pulse-field gel electrophoresis, or randomly amplified polymorphic DNA have been used to investigate population structure, evolution, and genetic relationships and support epidemiological and virulence investigations. However, these traditional typing techniques do not fully reveal the genetically heterogeneous nature of strains. The high-resolution provided by whole-genome sequencing (WGS), which is now more affordable and more commonly available in research and clinical settings, has unlocked the exploration of genetics at full resolution, permitting the determination of population structure, genetic diversity, identification of virulent clades, genetic markers, and other bacterial features of interest. This approach will likely become the new gold standard for strain typing as WGS instruments become more widely available and traditional typing techniques are gradually replaced.
PubMed: 38509941
DOI: 10.1016/j.heliyon.2024.e27818 -
Virulence Dec 2024The arginine deiminase system (ADS) has been identified in various bacteria and functions to supplement energy production and enhance biological adaptability. The...
The arginine deiminase system (ADS) has been identified in various bacteria and functions to supplement energy production and enhance biological adaptability. The current understanding of the regulatory mechanism of ADS and its effect on bacterial pathogenesis is still limited. Here, we found that the XRE family transcriptional regulator XtrSs negatively affected virulence and significantly repressed ADS transcription when the bacteria were incubated in blood. Electrophoretic mobility shift (EMSA) and lacZ fusion assays further showed that XtrSs directly bind to the promoter of ArgR, an acknowledged positive regulator of bacterial ADS, to repress ArgR transcription. Moreover, we provided compelling evidence that could utilize arginine via ADS to adapt to acid stress, while Δ enhanced this acid resistance by upregulating the ADS operon. Moreover, whole ADS-knockout increased arginine and antimicrobial NO in the infected macrophage cells, decreased intracellular survival, and even caused significant attenuation of bacterial virulence in a mouse infection model, while Δ consistently presented the opposite results. Our experiments identified a novel ADS regulatory mechanism in , whereby XtrSs regulated ADS to modulate NO content in macrophages, promoting intracellular survival. Meanwhile, our findings provide a new perspective on how evade the host's innate immune system.
Topics: Animals; Mice; Arginine; Bacterial Proteins; Gene Expression Regulation, Bacterial; Hydrolases; Macrophages; Streptococcal Infections; Streptococcus suis
PubMed: 38251714
DOI: 10.1080/21505594.2024.2306719 -
Microbial Genomics Mar 2024is a leading cause of infection in pigs, causing extensive economic losses. In addition, it can also infect wild fauna, and can be responsible for severe infections in...
is a leading cause of infection in pigs, causing extensive economic losses. In addition, it can also infect wild fauna, and can be responsible for severe infections in humans. Increasing antimicrobial resistance (AMR) has been described in worldwide and most of the AMR genes are carried by mobile genetic elements (MGEs). This contributes to their dissemination by horizontal gene transfer. A collection of 102 strains isolated from humans, pigs and wild boars in France was subjected to whole genome sequencing in order to: (i) study their genetic diversity, (ii) evaluate their content in virulence-associated genes, (iii) decipher the mechanisms responsible for their AMR and their association with MGEs, and (iv) study their ability to acquire extracellular DNA by natural transformation. Analysis by hierarchical clustering on principal components identified a few virulence-associated factors that distinguish invasive CC1 strains from the other strains. A plethora of AMR genes (=217) was found in the genomes. Apart from the frequently reported (B) and (O) genes, more recently described AMR genes were identified [(F)/, (D)]. Modifications in PBPs/MraY and GyrA/ParC were detected in the penicillin- and fluoroquinolone-resistant isolates respectively. New AMR gene-MGE associations were detected. The majority of the strains have the full set of genes required for competence, i.e for the acquisition of extracellular DNA (that could carry AMR genes) by natural transformation. Hence the risk of dissemination of these AMR genes should not be neglected.
Topics: Humans; Animals; Swine; Streptococcus suis; Virulence; France; Virulence Factors; DNA
PubMed: 38536216
DOI: 10.1099/mgen.0.001224 -
ACS Synthetic Biology Sep 2023is an important zoonotic pathogen that causes severe invasive disease in pigs and humans. Current methods for genome engineering of rely on the insertion of antibiotic...
is an important zoonotic pathogen that causes severe invasive disease in pigs and humans. Current methods for genome engineering of rely on the insertion of antibiotic resistance markers, which is time-consuming and labor-intensive and does not allow the precise introduction of small genomic mutations. Here we developed a system for CRISPR-based genome editing in , utilizing linear DNA fragments for homologous recombination (HR) and a plasmid-based negative selection system for bacteria not edited by HR. To enable the use of this system in other bacteria, we engineered a broad-host-range replicon in the CRISPR plasmid. We demonstrated the utility of this system to rapidly introduce multiple gene deletions in successive rounds of genome editing and to make precise nucleotide changes in essential genes. Furthermore, we characterized a mechanism by which can escape killing by a targeted Cas9-sgRNA complex in the absence of HR. A characteristic of this new mechanism is the presence of very slow-growing colonies in a persister-like state that may allow for DNA repair or the introduction of mutations, alleviating Cas9 pressure. This does not impact the utility of CRISPR-based genome editing because the escape colonies are easily distinguished from genetically edited clones due to their small colony size. Our CRISPR-based editing system is a valuable addition to the genetic toolbox for engineering of , as it accelerates the process of mutant construction and simplifies the removal of antibiotic markers between successive rounds of genome editing.
Topics: Humans; Animals; Swine; Streptococcus suis; CRISPR-Cas Systems; RNA, Guide, CRISPR-Cas Systems; Technology; Anti-Bacterial Agents
PubMed: 37602730
DOI: 10.1021/acssynbio.3c00110