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Emerging Microbes & Infections Dec 2024is a major bacterial pathogen in pigs and an emerging zoonotic pathogen. Different serotypes exhibit diverse characteristics in population structure and pathogenicity....
is a major bacterial pathogen in pigs and an emerging zoonotic pathogen. Different serotypes exhibit diverse characteristics in population structure and pathogenicity. Surveillance data highlight the significance of serotype 4 (SS4) in swine streptococcusis, a pathotype causing human infections. However, except for a few epidemiologic studies, the information on SS4 remains limited. In this study, we investigated the population structure, pathogenicity, and antimicrobial characteristics of SS4 based on 126 isolates, including one from a patient with septicemia. We discovered significant diversities within this population, clustering into six minimum core genome (MCG) groups (1, 2, 3, 4, 7-2, and 7-3) and five lineages. Two main clonal complexes (CCs), CC17 and CC94, belong to MCG groups 1 and 3, respectively. Numerous important putative virulence-associated genes are present in these two MCG groups, and 35.00% (7/20) of pig isolates from CC17, CC94, and CC839 (also belonging to MCG group 3) were highly virulent (mortality rate ≥ 80%) in zebrafish and mice, similar to the human isolate ID36054. Cytotoxicity assays showed that the human and pig isolates of SS4 strains exhibit significant cytotoxicity to human cells. Antimicrobial susceptibility testing showed that 95.83% of strains isolated from our labs were classified as multidrug-resistant. Prophages were identified as the primary vehicle for antibiotic resistance genes. Our study demonstrates the public health threat posed by SS4, expanding the understanding of SS4 population structure and pathogenicity characteristics and providing valuable information for its surveillance and prevention.
Topics: Streptococcus suis; Animals; Swine; Humans; Streptococcal Infections; Serogroup; Swine Diseases; Virulence; Mice; Genome, Bacterial; Zebrafish; Anti-Bacterial Agents; Phylogeny; Microbial Sensitivity Tests; Virulence Factors
PubMed: 38703011
DOI: 10.1080/22221751.2024.2352435 -
Journal of Applied Microbiology Apr 2021RpoE is quite immunogenic and can be used as a candidate vaccine for Streptococcus suis infection via immunoproteomics as reported in our previous studies. In this...
AIMS
RpoE is quite immunogenic and can be used as a candidate vaccine for Streptococcus suis infection via immunoproteomics as reported in our previous studies. In this study, we aimed to verify the immunogenicity of recombinant RpoE and its protective effect against of S. suis.
METHODS AND RESULTS
The RpoE protein was successfully expressed in Escherichia coli, and the purified recombinant protein was mixed with ISA206 to prepare an S. suis subunit vaccine. Mice were immunized with the RpoE subunit vaccine and then infected with the virulent S. suis strain ZY05719. Subunit vaccine-immunized mice achieved 50% protection, less pathological damage and less bacterial distribution in each organ compared with the control mice. Furthermore, in vitro culture, showed that mouse antisera significantly (P < 0·001) inhibited the growth of S. suis, and qRT-PCR results showed that RpoE successfully induced the up-regulation of IL-6 and TNF-α cytokines.
CONCLUSIONS
RpoE mice were vaccinated to obtain immune protection, which may be candidates for S. suis subunit vaccine.
SIGNIFICANCE AND IMPACT OF THE STUDY
The results of this study will provide new ideas for the development of safe and effective recombinant subunits vaccines for S. suis.
Topics: Animals; Bacterial Proteins; Escherichia coli; Female; Immunization; Mice; Recombinant Proteins; Serogroup; Sigma Factor; Streptococcal Infections; Streptococcal Vaccines; Streptococcus suis; Vaccines, Subunit
PubMed: 32996241
DOI: 10.1111/jam.14874 -
Microbiology Spectrum Feb 2022To investigate the presence and location of (T) in clinical Streptococcus suis isolates and explore the transmission ability and fitness cost of (T)-carrying mobile...
To investigate the presence and location of (T) in clinical Streptococcus suis isolates and explore the transmission ability and fitness cost of (T)-carrying mobile genetic elements among S. suis isolates, MICs were determined by broth microdilution. The presence of (T) in S. suis was detected by PCR. The genetic environment of (T) in S. suis was explored by whole-genome sequencing (WGS) analysis. Intraspecies and interspecies transmission were examined by electrotransformation. The fitness cost associated with the carriage of an (T)-harboring plasmid or an integrative and conjugative element (ICE) was examined by competition experiments. Of 237 nonduplicate strains, (T) was detected in 2 S. suis strains (SC262-ST954 and SC117-ST1314), with its location on a 5,125-bp plasmid in S. suis SC262 and on a 64,013-bp ICESC117 in S. suis SC117, respectively. Both the (T)-carrying plasmid pSC262 and the ICESC117 were transmissible by transformation. Plasmid pSC262 can replicate and express macrolide-lincosamide resistance in heterologous hosts, including S. aureus and S. pneumoniae. Both the (T)-carrying plasmid and the ICE posed a fitness cost to the host S. suis isolate. To the best of our knowledge, this is the first report of the macrolide-lincosamide-streptogramin B resistance gene (T) in S. suis. Its location on a plasmid or an ICE will aid in its transmission. The low detection rate of (T) gene among the S. suis population might be due to the fitness cost of the (T)-carrying plasmid and ICE. Macrolide and lincosamide resistance due to the presence of (T) have posed a challenge for the treatment of Gram-positive pathogens. Although the low detection rate of (T) gene among the S. suis population due to the fitness cost of the (T)-carrying plasmid and ICE, the presence of (T) in S. suis and its potential transmission to other Gram-positive pathogens will be of important significance.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Drug Resistance, Bacterial; Gene Transfer, Horizontal; Humans; Lincosamides; Macrolides; Microbial Sensitivity Tests; Staphylococcus aureus; Streptococcal Infections; Streptococcus pneumoniae; Streptococcus suis
PubMed: 35019703
DOI: 10.1128/spectrum.01657-21 -
International Journal of Molecular... Apr 2023, an encapsulated zoonotic pathogen, has been reported to cause a variety of infectious diseases, such as meningitis and streptococcal-toxic-shock-like syndrome....
, an encapsulated zoonotic pathogen, has been reported to cause a variety of infectious diseases, such as meningitis and streptococcal-toxic-shock-like syndrome. Increasing antimicrobial resistance has triggered the need for new treatments. In the present study, we found that isopropoxy benzene guanidine (IBG) significantly attenuated the effects caused by infection, in vivo and in vitro, by killing and reducing pathogenicity. Further studies showed that IBG disrupted the integrity of cell membranes and increased the permeability of cell membranes, leading to an imbalance in proton motive force and the accumulation of intracellular ATP. Meanwhile, IBG antagonized the hemolysis activity of suilysin and decreased the expression of gene. In vivo, IBG improved the viability of SS3-infected mice by reducing tissue bacterial load. In conclusion, IBG is a promising compound for the treatment of infections, given its antibacterial and anti-hemolysis activity.
Topics: Animals; Mice; Streptococcus suis; Benzene; Guanidine; Streptococcal Infections; Guanidines; Hemolysin Proteins
PubMed: 37108521
DOI: 10.3390/ijms24087354 -
Frontiers in Medicine 2021is a human zoonotic pathogen of occupational origin, with infection acquired through contact with live pigs or pig meat. Pig farming is one of Catalonia's biggest...
is a human zoonotic pathogen of occupational origin, with infection acquired through contact with live pigs or pig meat. Pig farming is one of Catalonia's biggest industries and as a result this region of Spain has one of the highest density pig populations per km. The aim of our study was to describe the infections caused by occurring in that area over a 9-year period. A retrospective, multi-center study was carried out by searching records from 15 hospitals in Catalonia for the period between 2010 and 2019. Over the study period altogether nine cases of infection were identified in five hospitals, with five of these cases occurring in the 2018-2019 period. The mean age of patients was 48 ± 8.9 years and all of them were males. Five patients (55.6%) worked in pig farms. The most frequent manifestation of infection was meningitis (5 cases; 55.6%) followed by septic arthritis (3 cases; 33.3%). None of the patients died at 30 days; nonetheless, 4 developed hearing loss as a long-term complication. The most commonly identified infection was meningitis. Over 50% of the episodes occurred in the last 2 years and have affected pig farm workers. Further surveillance is needed in order to know its prevalence.
PubMed: 34957160
DOI: 10.3389/fmed.2021.792233 -
Microbiology Spectrum Aug 2022Streptococcus suis is an important zoonotic bacterial pathogen posing a threat to the pig industry as well as public health, for which the mechanisms of growth and cell...
Streptococcus suis is an important zoonotic bacterial pathogen posing a threat to the pig industry as well as public health, for which the mechanisms of growth and cell division remain largely unknown. Developing convenient genetic tools that can achieve strictly controlled gene expression is of great value for investigating these fundamental physiological processes of S. suis. In this study, we first identified three strong constitutive promoters, P, P, and P, in S. suis. Promoter P was used to drive the expression of repressor genes and , and the operator sequences were added within promoters P and P. By optimizing the insertion sites of the operator sequence, we successfully constructed an anhydrotetracycline (ATc)-inducible expression system and an isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible expression system in S. suis. We showed that these two systems provided inducer-concentration- and induction-time-dependent expression of the reporter gene. By using these tools, we investigated the subcellular localization of a key cell division protein, FtsZ, which showed that it could be correctly localized to the midcell region. In addition, we constructed a conditional knockout strain for the gene, which is an essential gene, and showed that our ATc-inducible promoter could provide strictly controlled expression of in , suggesting that our inducible expression systems can be used for deletion of essential genes in S. suis. Therefore, for the first time we developed two inducible expression systems in S. suis and showed their applications in the study of an important cell division protein and an essential gene. These genetic tools will further facilitate the functional study of other important genes of S. suis. Streptococcus suis is an important zoonotic bacterial pathogen. Studying the mechanisms of cell growth and division is important for the identification of novel antimicrobial drug targets. Inducible expression systems can provide strictly controlled expression of the protein of interest and are useful tools to study the functions of physiologically important proteins. However, there is a lack of convenient genetic tools that can achieve inducible protein expression in S. suis. In this study, we developed two (ATc-inducible and IPTG-inducible) inducible expression systems and showed their applications in a subcellular localization study of a cell division protein and the construction of conditional knockout of essential genes in S. suis. These systems will be useful for functional studies of important proteins of S. suis.
Topics: Animals; Bacterial Proteins; Base Sequence; Cell Division; Isopropyl Thiogalactoside; Promoter Regions, Genetic; Streptococcus suis; Swine
PubMed: 35758678
DOI: 10.1128/spectrum.00363-22 -
Probiotics and Antimicrobial Proteins Apr 2021Nisin is a promising therapeutic candidate because of its potent activity against Gram-positive bacteria. The present study aimed to describe the in vitro and in vivo...
Nisin is a promising therapeutic candidate because of its potent activity against Gram-positive bacteria. The present study aimed to describe the in vitro and in vivo antibacterial effects of nisin against Streptococcus suis, an important zoonotic pathogen. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of nisin against different S. suis strains ranged from 0.12 to 4.0 μg/mL and from 0.25 to 8.0 μg/mL, respectively. Time-killing curve assays illustrated that nisin killed 100% of tested virulent S. suis strains within 4 h when used at 2× MIC, which indicates the rapid bactericidal activity of nisin against the bacteria. Transmission and scanning electron microscopy revealed that nisin destroyed S. suis cell membrane integrity and affected its cellular ultrastructure, including a significantly wrinkled surface, intracellular content leakage, and cell lysis. In addition, nisin inhibited biofilm formation by S. suis in a concentration-dependent manner and exhibited strong degrading activities against preformed biofilms. More importantly, nisin displayed antimicrobial activity against S. suis infection in vivo. Upon treatment with 5.0-10 mg/kg nisin solution, the survival rates of mice challenged with a lethal dose of virulent S. suis virulent ranged 87.5-100%. Nisin significantly decreased bacterial proliferation and translocation in the mouse spleen, brain, and blood. These results indicate that nisin has potential as a novel antimicrobial agent for the clinical treatment and prevention of infection caused by S. suis in animals.
Topics: Animals; Anti-Bacterial Agents; Mice; Microscopy, Electron, Scanning; Nisin; Streptococcus suis
PubMed: 33404866
DOI: 10.1007/s12602-020-09732-w -
Proceedings of the National Academy of... Nov 2023The expansion and intensification of livestock production is predicted to promote the emergence of pathogens. As pathogens sometimes jump between species, this can...
The expansion and intensification of livestock production is predicted to promote the emergence of pathogens. As pathogens sometimes jump between species, this can affect the health of humans as well as livestock. Here, we investigate how livestock microbiota can act as a source of these emerging pathogens through analysis of , a ubiquitous component of the respiratory microbiota of pigs that is also a major cause of disease on pig farms and an important zoonotic pathogen. Combining molecular dating, phylogeography, and comparative genomic analyses of a large collection of isolates, we find that several pathogenic lineages of emerged in the 19th and 20th centuries, during an early period of growth in pig farming. These lineages have since spread between countries and continents, mirroring trade in live pigs. They are distinguished by the presence of three genomic islands with putative roles in metabolism and cell adhesion, and an ongoing reduction in genome size, which may reflect their recent shift to a more pathogenic ecology. Reconstructions of the evolutionary histories of these islands reveal constraints on pathogen emergence that could inform control strategies, with pathogenic lineages consistently emerging from one subpopulation of and acquiring genes through horizontal transfer from other pathogenic lineages. These results shed light on the capacity of the microbiota to rapidly evolve to exploit changes in their host population and suggest that the impact of changes in farming on the pathogenicity and zoonotic potential of is yet to be fully realized.
Topics: Animals; Humans; Swine; Streptococcal Infections; Farms; Swine Diseases; Virulence; Streptococcus suis; Livestock
PubMed: 37963246
DOI: 10.1073/pnas.2307773120 -
Virulence Dec 2023type 2 (SS2), a major emerging/re-emerging zoonotic pathogen found in humans and pigs, can cause severe clinical infections, and pose public health issues. Our previous...
type 2 (SS2), a major emerging/re-emerging zoonotic pathogen found in humans and pigs, can cause severe clinical infections, and pose public health issues. Our previous studies recognized peptidyl-prolyl isomerase (PrsA) as a critical virulence factor promoting SS2 pathogenicity. PrsA contributed to cell death and operated as a pro-inflammatory effector. However, the molecular pathways through which PrsA contributes to cell death are poorly understood. Here in this study, we prepared the recombinant PrsA protein and found that pyroptosis and necroptosis were involved in cell death stimulated by PrsA. Specific pyroptosis and necroptosis signalling inhibitors could significantly alleviate the fatal effect. Cleaved caspase-1 and IL-1β in pyroptosis with phosphorylated MLKL proteins in necroptosis pathways, respectively, were activated after PrsA stimulation. Truncated protein fragments of enzymatic PPIase domain (PPI), N-terminal (NP), and C-terminal (PC) domains fused with PPIase, were expressed and purified. PrsA flanking - or C-terminal but not enzymatic PPIase domain was found to be critical for PrsA function in inducing cell death and inflammation. Additionally, PrsA protein could be anchored on the cell surface to interact with host cells. However, Toll-like receptor 2 (TLR2) was not implicated in cell death and recognition of PrsA. PAMPs of PrsA could not promote TLR2 activation, and no rescued phenotypes of death were shown in cells blocking of TLR2 receptor or signal-transducing adaptor of MyD88. Overall, these data, for the first time, advanced our perspective on PrsA function and elucidated that PrsA-induced cell death requires its flanking - or C-terminal domain but is dispensable for recognizing TLR2. Further efforts are still needed to explore the precise molecular mechanisms of PrsA-inducing cell death and, therefore, contribution to SS2 pathogenicity.
Topics: Animals; Humans; Cell Death; Peptidylprolyl Isomerase; Pyroptosis; Streptococcus suis; Swine; Toll-Like Receptor 2; Bacterial Proteins; Streptococcal Infections
PubMed: 37641974
DOI: 10.1080/21505594.2023.2249779 -
Scientific Reports May 2023Streptococcus suis (S. suis) infection can cause clinically severe meningitis, arthritis, pneumonia and septicemia in pigs. To date, studies on the serotypes, genotypes...
Streptococcus suis (S. suis) infection can cause clinically severe meningitis, arthritis, pneumonia and septicemia in pigs. To date, studies on the serotypes, genotypes and antimicrobial susceptibility of S. suis in affected pigs in Taiwan are rare. In this study, we comprehensively characterized 388 S. suis isolates from 355 diseased pigs in Taiwan. The most prevalent serotypes of S. suis were serotypes 3, 7 and 8. Multilocus sequence typing (MLST) revealed 22 novel sequence types (STs) including ST1831-1852 and one new clonal complex (CC), CC1832. The identified genotypes mainly belonged to ST27, ST94 and ST1831, and CC27 and CC1832 were the main clusters. These clinical isolates were highly susceptible to ceftiofur, cefazolin, trimethoprim/sulfamethoxazole and gentamicin. The bacteria were prone to be isolated from cerebrospinal fluid and synovial fluid in suckling pigs with the majority belonging to serotype 1 and ST1. In contrast, ST28 strains that corresponded to serotypes 2 and 1/2 were more likely to exist in the lungs of growing-finishing pigs, which posted a higher risk for food safety and public health. This study provided the genetic characterization, serotyping and the most current epidemiological features of S. suis in Taiwan, which should afford a better preventative and treatment strategy of S. suis infection in pigs of different production stages.
Topics: Swine; Animals; Serogroup; Multilocus Sequence Typing; Streptococcus suis; Taiwan; Serotyping; Streptococcal Infections; Swine Diseases
PubMed: 37217544
DOI: 10.1038/s41598-023-33778-9