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Virulence Oct 2017
Topics: Blood-Brain Barrier; Carrier Proteins; Complement Factor H; Humans; Streptococcal Infections; Streptococcus suis; Virulence
PubMed: 28622084
DOI: 10.1080/21505594.2017.1342027 -
Journal of Veterinary Diagnostic... Mar 2017Sixteen isolates of gram-positive, coccoid bacteria were obtained from clinical cases of diverse conditions in cattle and identified as Streptococcus suis using 16S...
Sixteen isolates of gram-positive, coccoid bacteria were obtained from clinical cases of diverse conditions in cattle and identified as Streptococcus suis using 16S ribosomal DNA gene sequencing and other bacterial identification methods. None of the isolates could be assigned to any of the known S. suis capsular types. Virulence-associated gene profiling that targeted muramidase-released protein, extracellular protein factor, suilysin, 89-kb pathogenicity island, and arginine deiminase ( arcA) genes were negative except for 1 isolate that was arcA positive. The arcA-positive isolate caused severe widespread lesions, including multiorgan suppurative and hemorrhagic inflammation in the meninges, lung, liver, spleen, lymph nodes, and serosae of heart and intestines. The other isolates were primarily associated with meningitis, bronchopneumonia, and multifocal acute necrotizing hepatitis. The isolates differed from each other by 4-6 fragments when examined by pulsed-field gel electrophoresis, indicating they are possibly related. The isolates were susceptible to ampicillin, penicillin, and tiamulin. Resistance was noted to sulfadimethoxine (93%), oxytetracycline (86%), chlortetracycline (86%), neomycin (67%), tilmicosin (47%), clindamycin (47%), enrofloxacin (33%), gentamicin (13%), florfenicol (7%), trimethoprim-sulfamethoxazole (7%), and spectinomycin (53%). Multi-drug resistance (defined as resistance to at least 1 agent in 3 or more antimicrobial classes) was detected in 67% of the isolates. The pathology observations provide evidence that S. suis may be an important pathogen of bovine calves. S. suis is an agent that clinical bacteriology laboratories should consider when dealing with cases involving cattle.
Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Microbial Sensitivity Tests; Streptococcal Infections; Streptococcus suis; Virulence; Wisconsin
PubMed: 28166707
DOI: 10.1177/1040638717690014 -
PeerJ 2022is a zoonotic pathogen that can cause invasive infections in humans who are in close contact with infected pigs or contaminated pork-derived products. serotype 2...
BACKGROUND
is a zoonotic pathogen that can cause invasive infections in humans who are in close contact with infected pigs or contaminated pork-derived products. serotype 2 sequence type (ST) 1 strains are mostly associated with meningitis, whereas ST104 strains are mostly recovered from sepsis cases in humans. No data are available for comparison of the ST1 and ST104 strains at the genomic level, particularly concerning virulence-associated genes. Thus, genomic comparison of both STs was performed in this study.
METHODS
An ST1 isolate (ID26154) from the cerebrospinal fluid of a patient with meningitis and an ST104 isolate (ID24525) from the blood of a patient with sepsis were subjected to shotgun pyrosequencing using the 454 GS Junior System. Genomic comparison was conducted between the ST1 isolate and the ST104 isolate using the Artemis Comparison Tool (ACT) to identify the region of differences (RDs) between ST1 and ST104.
RESULTS
Fifty-eight RDs were unique to the ST104 genome and were mainly involved in metabolism and cell functional activities, cell wall anchored proteins, bacteriophages and mobile genetic elements, ABC-type transporters, two-component signal transductions, and lantibiotic proteins. Some virulence genes mostly found in ST1 strains were also present in the ST104 genome. Whole-genome comparison is a powerful tool for identifying genomic region differences between different STs of serotype 2, leading to the identification of the molecular basis of virulence involved in the pathogenesis of the infection.
Topics: Humans; Animals; Swine; Streptococcus suis; Serogroup; Streptococcal Infections; Genomics; Sepsis
PubMed: 36221266
DOI: 10.7717/peerj.14144 -
Journal of Microbiology (Seoul, Korea) Sep 2022Streptococcus suis type 2 (S. suis type 2, SS2), an infectious pathogen which is zoonotic and can induce severely public health concern. Our previous research identified...
Streptococcus suis type 2 (S. suis type 2, SS2), an infectious pathogen which is zoonotic and can induce severely public health concern. Our previous research identified a newly differential secreted effector of tagatose-bisphosphate aldolase (LacD) mediated by VirD4 factor within the putative type IV secretion system of SS2, whereas the functional basis and roles in virulence of LacD remain elusive. Here in this study, the LacD was found enzymatic and can be activated to express under oxidative stress. Gene mutant and its complemental strain (ΔlacD and cΔlacD) were constructed to analyze the phenotypes, virulence and transcriptomic profiles as compared with the parental strain. The lacD gene deletion showed no effect on growth capability and cells morphology of SS2. However, reduced tolerance to oxidative and heat stress conditions, increased antimicrobial susceptibility to ciprofloxacin and kanamycin were found in ΔlacD strain. Further, the LacD deficiency led to weakened invasion and attenuated virulence since an easier phagocytosed and more prone to be cleared of SS2 in macrophages were shown in ΔlacD mutant. Distinctive transcriptional profiling in ΔlacD strain and typical down-regulated genes with significant mRNA changes including alcohol dehydrogenase, GTPase, integrative and conjugative elements, and iron ABC transporters which were mainly involved in cell division, stress response, antimicrobial susceptibility and virulence regulation, were examined and confirmed by RNA sequencing and real time qPCR. In summary, the results demonstrated for the first time that LacD was a pluripotent protein mediated the metabolic, stress and virulent effect of SS2.
Topics: Anti-Infective Agents; Bacterial Proteins; Gene Deletion; Humans; Serogroup; Streptococcal Infections; Streptococcus suis; Virulence
PubMed: 35984615
DOI: 10.1007/s12275-022-2146-4 -
Microbiology Spectrum Jun 2023Streptococcus suis is a zoonotic pathogen that causes disease in humans after exposure to infected pigs or pig-derived food products. In this study, we examined the...
Streptococcus suis is a zoonotic pathogen that causes disease in humans after exposure to infected pigs or pig-derived food products. In this study, we examined the serotype distribution, antimicrobial resistance phenotypes and genotypes, integrative and conjugative elements (ICEs), and associated genomic environments of S. suis isolates from humans and pigs in China from 2008 to 2019. We identified isolates of 13 serotypes, predominated by serotype 2 (40/96; 41.7%), serotype 3 (10/96; 10.4%), and serotype 1 (6/96; 6.3%). Whole-genome sequencing analysis revealed that these isolates possessed 36 different sequence types (STs), and ST242 and ST117 were the most prevalent. Phylogenetic analysis revealed possible animal and human clonal transmission, while antimicrobial susceptibility testing indicated high-level resistance to macrolides, tetracyclines, and aminoglycosides. These isolates carried 24 antibiotic resistance genes (ARGs) that conferred resistance to 7 antibiotic classes. The antibiotic resistance genotypes were directly correlated with the observed phenotypes. We also identified ICEs in 10 isolates, which were present in 4 different genetic environments and possessed differing ARG combinations. We also predicted and confirmed by PCR analysis the existence of a translocatable unit (TU) in which the oxazolidinone resistance gene was flanked by IS elements. One-half (5/10) of the ICE-carrying strains could be mobilized by conjugation. A comparison of the parental recipient with an ICE-carrying transconjugant in a mouse thigh infection model indicated that the ICE strain could not be eliminated with tetracycline treatment. S. suis therefore poses a significant challenge to global public health and requires continuous monitoring, especially for the presence of ICEs and associated ARGs that can be transferred via conjugation. S. suis is a serious zoonotic pathogen. In this study, we investigated the epidemiological and molecular characteristics of 96 S. suis isolates from 10 different provinces of China from 2008 to 2019. A subset of these isolates (10) carried ICEs that were able to be horizontally transferred among isolates of different S. suis serotypes. A mouse thigh infection model revealed that ICE-facilitated ARG transfer promoted resistance development. S. suis requires continuous monitoring, especially for the presence of ICEs and associated ARGs that can be transferred via conjugation.
Topics: Humans; Swine; Animals; Mice; Streptococcus suis; Phylogeny; Drug Resistance, Microbial; Anti-Bacterial Agents; Oxazolidinones
PubMed: 37154736
DOI: 10.1128/spectrum.00309-23 -
Emerging Microbes & Infections Dec 2021is one of the important emerging zoonotic pathogens. Serotype 2 is most prevalent in patients worldwide. In the present study, we first isolated one serotype 7 strain...
is one of the important emerging zoonotic pathogens. Serotype 2 is most prevalent in patients worldwide. In the present study, we first isolated one serotype 7 strain GX69 from the blood culture of a patient with septicemia complicated with pneumonia in China. In order to deepen the understanding of serotype 7 population characteristics, we investigated the phylogenetic structure, genomic features, and virulence of serotype 7 population, including 35 strains and 79 genomes. Significant diversities were revealed in serotype 7 population, which were clustered into 22 sequence types (STs), five minimum core genome (MCG) groups, and six lineages. Lineages 1, 3a, and 6 were mainly constituted by genomes from Asia. Genomes of Lineages 2, 3b, and 5a were mainly from Northern America. Most of genomes from Europe (41/48) were clustered into Lineage 5b. In addition to strain GX69, 13 of 21 serotype 7 representative strains were classified as virulent strains using the C57BL/6 mouse model. Virulence-associated genes preferentially present in highly pathogenic serotype 2 strains were not suitable as virulence indicators for serotype 7 strains. Integrative mobilizable elements were widespread and may play a critical role in disseminating antibiotic resistance genes of serotype 7 strains. Our study confirmed serotype 7 is a non-negligible pathotype and deepened the understanding of the population structure of serotype 7, which provided valuable information for the improved surveillance of this serotype.
Topics: Aged; Animals; Anti-Bacterial Agents; Bacteremia; Bacterial Zoonoses; China; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Female; Genome, Bacterial; Humans; Interspersed Repetitive Sequences; Mice, Inbred C57BL; Microbial Sensitivity Tests; Multilocus Sequence Typing; Phylogeny; Pneumonia, Bacterial; Polymorphism, Single Nucleotide; Serogroup; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases; Virulence; Virulence Factors; Mice
PubMed: 34635002
DOI: 10.1080/22221751.2021.1988725 -
Applied Microbiology and Biotechnology Oct 2020Streptococcus suis (S. suis) is an important zoonotic agent, which seriously impacts the pig industry and human health in various countries. Biofilm formation is likely... (Review)
Review
Streptococcus suis (S. suis) is an important zoonotic agent, which seriously impacts the pig industry and human health in various countries. Biofilm formation is likely contributing to the virulence and drug resistance in S. suis. A better knowledge of biofilm formation as well as to biofilm-dependent drug resistance mechanisms in S. suis can be of great significance for the prevention and treatment of S. suis infections. This literature review updates the latest scientific data related to biofilm formation in S. suis and its impact on drug tolerance and resistance.Key points• Biofilm formation is the important reasons for drug resistance of SS infections.• The review includes the regulatory mechanism of SS biofilm formation.• The review includes the drug resistance mechanisms of SS biofilm.
Topics: Animals; Biofilms; Drug Resistance, Microbial; Streptococcal Infections; Streptococcus suis; Swine; Virulence
PubMed: 32897417
DOI: 10.1007/s00253-020-10873-9 -
BMC Veterinary Research Oct 2019Streptococcus suis is a prominent pathogen causing septicemia and meningitis in swine and humans. Bacitracin is used widely as a growth promoter in animal feed and to...
BACKGROUND
Streptococcus suis is a prominent pathogen causing septicemia and meningitis in swine and humans. Bacitracin is used widely as a growth promoter in animal feed and to control the spread of necrotic enteritis in most developing countries. This study aimed to characterize a novel membrane transporter module Sst comprising SstE, SstF, and SstG for bacitracin resistance.
RESULTS
Comparative genomics and protein homology analysis found a potential efflux pump SstFEG encoded upstream of well-known bacitracin-resistance genes bceAB and bceRS. A four-fold decrease in bacitracin susceptibility was observed in sstFEG deletion mutant comparing with S. suis wildtype strain CZ130302. Further studies indicated that the bacitracin tolerance mediated by SstFEG is not only independent of the BceAB transporter, but also regulated by the two-component system BceSR. Given that SstFEG are harbored by almost all virulent strains, but not in the avirulent strains, we managed to explore its potential role in bacterial pathogencity. Indeed, our results showed that SstFEG is involved in S. suis colonization and virulence in animal infection model by its potential competitive survival advantage against host bactericidal effect.
CONCLUSION
To our knowledge, this is the first study to functionally characterize the bacitracin efflux pump in S. suis to provide evidence regarding the important roles of the novel ABC transporter system SstFEG with respect to drug resistance and virulence.
Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents, Local; Bacitracin; Bacterial Proteins; Drug Resistance, Bacterial; Female; Gene Deletion; Gene Expression Regulation, Bacterial; Membrane Transport Proteins; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Streptococcal Infections; Streptococcus suis; Virulence
PubMed: 31660968
DOI: 10.1186/s12917-019-2115-2 -
Microbiological Research 2019Streptococcus suis has received increasing attention for its involvement in severe infections in pigs and humans; however, their pathogenesis remains unclear. ClpX and...
Streptococcus suis has received increasing attention for its involvement in severe infections in pigs and humans; however, their pathogenesis remains unclear. ClpX and ClpP, two subunits of the ATP-dependent caseinolytic protease Clp, play key roles in bacterial adaptation to various environmental stresses. In this study, a virulent S. suis serotype 2 strain, ZY05719, was employed to construct clpX and clpP deletion mutants (ΔclpX and ΔclpP, respectively) and their complementation strains. Both ΔclpX and ΔclpP displayed significantly reduced adaptability compared with the wild-type strain, evident through several altered phenotypes: formation of long cell chains, tendency to aggregate in culture, and reduced growth under acidic pH and HO-induced oxidative stress. ClpP and ClpX were required for the optimal growth during heat and cold stress, respectively. An in vitro experiment on RAW264.7 macrophage cells showed significantly increased sensitivity of ΔclpX and ΔclpP to phagocytosis compared with the wild-type strain. Mouse infection assays verified the deletion of clpX and clpP led to not only fewer clinical symptoms and lower mortality but also to a marked attenuation in bacterial colonization. These virulence-related phenotypes were restored by genetic complementation. Furthermore, the deletion of clpX or clpP caused a significant decrease in the expression of sodA, tpx, and apuA compared with the wild-type strain, suggesting that these genes may be regulated by ClpX and ClpP as downstream response factors to facilitate the bacterial tolerance against various environmental stresses. Taken together, these results suggest that ClpX and ClpP play important roles in stress tolerance for achieving the full virulence of S. suis serotype 2 during infection.
Topics: ATPases Associated with Diverse Cellular Activities; Animals; Bacterial Proteins; Biofilms; Cold-Shock Response; Endopeptidase Clp; Gene Deletion; Gene Expression Regulation, Bacterial; Heat-Shock Response; Hydrogen Peroxide; Hydrogen-Ion Concentration; Mice; Molecular Chaperones; Osmotic Pressure; Oxidative Stress; Phagocytosis; RAW 264.7 Cells; Streptococcal Infections; Streptococcus suis; Transcriptome; Virulence; Virulence Factors
PubMed: 31178057
DOI: 10.1016/j.micres.2019.04.003 -
Journal of Applied Microbiology Mar 2021This study aimed to investigate the antimicrobial resistance (AMR) profiles and genotypes of Streptococcus suis from Jiangxi Province, China.
AIMS
This study aimed to investigate the antimicrobial resistance (AMR) profiles and genotypes of Streptococcus suis from Jiangxi Province, China.
METHODS AND RESULTS
A total of 314 nasal swab samples were collected from clinically healthy pigs, with a positive isolation rate of S. suis of 34·08%. Antimicrobial susceptibility testing showed that more than 80% of the isolates were susceptible to vancomycin, penicillin, minocycline and chloramphenicol. A high frequency of resistance to clindamycin, tetracycline, clarithromycin and erythromycin was observed. All of the isolates were resistant to three or more categories of antimicrobials. The erm(B) and tet(O) served as the most frequent genotypes that contributed to lincosamide, macrolide and tetracycline resistances. A part of macrolide-resistant genotypes could not exhibit specific phenotypes. Finally, integrative and conjugative elements (ICEs) were identified in 28·97% of the isolates.
CONCLUSIONS
The multidrug resistance of S. suis has widely emerged in Jiangxi Province. The most prevalent resistance genes and genotypes were similar to those in other regions or countries. The presence of ICEs is increasing the risk of horizontal transfer of AMR genes.
SIGNIFICANCE AND IMPACT OF THE STUDY
The findings could provide guidance for the rational use of antimicrobial drugs and be helpful for monitoring the AMR information of S. suis in China.
Topics: Animals; Anti-Bacterial Agents; China; DNA Transposable Elements; Drug Resistance, Multiple, Bacterial; Genes, Bacterial; Genotype; Microbial Sensitivity Tests; Phenotype; Streptococcal Infections; Streptococcus suis; Swine; Swine Diseases
PubMed: 32881196
DOI: 10.1111/jam.14831