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"Streptococcal Infections - veterinary"
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Streptococcus equi Infections in Horses: Guidelines for Treatment, Control, and Prevention of Strangles—Revised Consensus Statement
2018
This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the “gold standard” for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the importance of judicious use of antibiotics in horses with strangles. This updated consensus statement reviews current vaccine technology and the importance of linking vaccination with currently advocated disease control and prevention programs to facilitate the eradication of endemic infections while safely maintaining herd immunity. Differentiation between immune responses to primary and repeated exposure of subclinically infected animals and responses induced by vaccination is also addressed.
Journal Article
Rapid onsets of warming events trigger mass mortality of coral reef fish
by
Genin, Amatzia
,
Raitsos, Dionysios E.
,
Levy, Liraz
in
Animals
,
Anthozoa
,
Atmospheric pressure
2020
Our study reveals a hitherto overlooked ecological threat of climate change. Studies of warming events in the ocean have typically focused on the events’ maximum temperature and duration as the cause of devastating disturbances in coral reefs, kelp forests, and rocky shores. In this study, however, we found that the rate of onset (Ronset), rather than the peak, was the likely trigger of mass mortality of coral reef fishes in the Red Sea. Following a steep rise in water temperature (4.2 °C in 2.5 d), thermally stressed fish belonging to dozens of species became fatally infected by Streptococcus iniae. Piscivores and benthivores were disproportionately impacted whereas zooplanktivores were spared. Mortality rates peaked 2 wk later, coinciding with a second warming event with extreme Ronset. The epizootic lasted ∼2 mo, extending beyond the warming events through the consumption of pathogen-laden carcasses by uninfected fish. The warming was widespread, with an evident decline in wind speed, barometric pressure, and latent heat flux. A reassessment of past reports suggests that steep Ronset was also the probable trigger of mass mortalities of wild fish elsewhere. If the ongoing increase in the frequency and intensity of marine heat waves is associated with a corresponding increase in the frequency of extreme Ronset, calamities inflicted on coral reefs by the warming oceans may extend far beyond coral bleaching.
Journal Article
Protection induced in pigs previously infected by the non-virulent strain 1330 of Streptococcus suis serotype 2 is not due to the secretion of the bacteriocin suicin
2025
Streptococcus suis is a systemic pathogen of swine and imposes a significant economic burden on the swine industry. Disease with S. suis is controlled with antibiotic treatment and vaccination with inactivated vaccines, which can be derived from the strains circulating on the farm. Inactivated vaccines have shown mixed results with minimal data supporting reductions in morbidity and mortality following their use. With increasing restrictions on antibiotic use and increasing concerns surrounding antimicrobial resistance, alternatives to antibiotics or novel, highly effective vaccines are needed for treating or preventing disease with S. suis . Bacteriocins are a potential alternative to antibiotics, as bacteriocins are antimicrobial peptides produced by bacteria. However, the use of bacteriocins to limit pathogenic S. suis remains relatively under-examined. Live vaccines are a potential novel and effective method of preventing disease, as they provide competition for pathogenic strains and would limit pathogenic strain colonization while stimulating a protective immune response. This study investigated the use of an avirulent, bacteriocin producing isolate of S. suis (90–1330) as an intranasal vaccine and evaluated the role of the bacteriocin by comparing protection to animals inoculated with a mutant lacking bacteriocin production (90–1330Δ suicin ). Animals were protected from systemic disease when challenged with a virulent isolate 21 days after inoculation with either 90–1330 or 90–1330Δ suicin but were not protected when challenged 3 days after inoculation. Evaluation of antibody titers showed increased titers 21 days post-inoculation, and the humoral response was likely providing systemic protection. Although 90–1330 was unable to protect animals challenged 3 days post-inoculation, the strain should be considered a good candidate for vaccine development. S. suis 90–1330 was able to induce a protective immune response with a single intranasal inoculation and bacteriocin production may be able to contribute to protection when animals have a lower exposure dose, as in a production setting.
Journal Article
Immune response induced by a Streptococcus suis multi-serotype autogenous vaccine used in sows to protect post-weaned piglets
by
Gaudreau, Annie
,
Segura, Mariela
,
Obradovic, Milan R.
in
Animals
,
antibiotics
,
antibody formation
2024
Streptococcus suis
is a bacterial pathogen that causes important economic losses to the swine industry worldwide. Since there are no current commercial vaccines, the use of autogenous vaccines applied to gilts/sows to enhance transfer of passive immunity is an attractive alternative to protect weaned piglets. However, there is no universal standardization in the production of autogenous vaccines and the vaccine formulation may be highly different among licenced manufacturing laboratories. In the present study, an autogenous vaccine that included
S. suis
serotypes 2, 1/2, 5, 7 and 14 was prepared by a licensed laboratory and administrated to gilts using a three-dose program prior to farrowing. The antibody response in gilts as well as the passive transfer of antibodies to piglets was then evaluated. In divergence with previously published data with an autogenous vaccine produced by a different company, the increased response seen in gilts was sufficient to improve maternal antibody transfer to piglets up to 5 weeks of age. However, piglets would still remain susceptible to
S. suis
disease which often appears during the second part of the nursery period. Vaccination did not affect the shedding of
S. suis
(as well as that of the specific
S. suis
serotypes included in the vaccine) by either gilts or piglets. Although all antibiotic treatments were absent during the trial, the clinical protective effect of the vaccination program with the autogenous vaccine could not be evaluated, since limited
S. suis
cases were present during the trial, confirming the need for a complete evaluation of the clinical protection that must include laboratory confirmation of the aetiological agent involved in the presence of
S. suis
-associated clinical signs. Further studies to evaluate the usefulness of gilt/sow vaccination with autogenous vaccines to protect nursery piglets should be done.
Journal Article
Transcriptomic analysis of equine placenta reveals key regulators and pathways involved in ascending placentitis
by
Dini, Pouya
,
Loux, Shavahn
,
Esteller-Vico, Alejandro
in
Abortion
,
Animals
,
Bacterial infections
2021
Improved understanding of the molecular mechanisms underlying ascending equine placentitis holds the potential for the development of new diagnostic tools and therapies to forestall placentitis-induced preterm labor. The current study characterized the equine placental transcriptome (chorioallantois [CA] and endometrium [EN]) during placentitis (placentitis group, n = 6) in comparison to gestationally-matched controls (control group, n = 6). Transcriptome analysis identified 2953 and 805 differentially expressed genes in CA and EN during placentitis, respectively. Upstream regulator analysis revealed the central role of toll-like receptors (TLRs) in triggering the inflammatory signaling, and consequent immune-cell chemotaxis. Placentitis was associated with the upregulation of matrix metalloproteinase (MMP1, MMP2, and MMP9) and apoptosis-related genes such as caspases (CASP3, CASP4, and CASP7) in CA. Also, placentitis was associated with downregulation of transcripts coding for proteins essential for placental steroidogenesis (SRD5A1 and AKR1C1), progestin signaling (PGRMC1 and PXR) angiogenesis (VEGFA, VEGFR2, and VEGFR3), and nutrient transport (GLUT12 and SLC1A4), as well as upregulation of hypoxia-related genes (HIF1A and EGLN3), which could explain placental insufficiency during placentitis. Placentitis was also associated with aberrant expression of several placenta-regulatory genes, such as PLAC8, PAPPA, LGALS1, ABCG2, GCM1, and TEPP, which could negatively affect placental functions. In conclusion, our findings revealed for the first time the key regulators and mechanisms underlying placental inflammation, separation, and insufficiency during equine placentitis, which might lead to the development of efficacious therapies or diagnostic aids by targeting the key molecular pathways. Summary sentence This is the first study to characterize the equine placenta transcriptome to identify the key regulators and pathways underlying placental inflammation, separation, and insufficiency during the equine ascending placentitis. Graphical Abstract
Journal Article
AI-2 quorum sensing-induced galactose metabolism activation in Streptococcus suis enhances capsular polysaccharide-associated virulence
2024
Bacteria utilize intercellular communication to orchestrate essential cellular processes, adapt to environmental changes, develop antibiotic tolerance, and enhance virulence. This communication, known as quorum sensing (QS), is mediated by the exchange of small signalling molecules called autoinducers. AI-2 QS, regulated by the metabolic enzyme LuxS (S-ribosylhomocysteine lyase), acts as a universal intercellular communication mechanism across gram-positive and gram-negative bacteria and is crucial for diverse bacterial processes. In this study, we demonstrated that in
Streptococcus suis
(
S. suis
), a notable zoonotic pathogen, AI-2 QS enhances galactose utilization, upregulates the Leloir pathway for capsular polysaccharide (CPS) precursor production, and boosts CPS synthesis, leading to increased resistance to macrophage phagocytosis. Additionally, our molecular docking and dynamics simulations suggest that, similar to
S. pneumoniae
, FruA, a fructose-specific phosphoenolpyruvate phosphotransferase system prevalent in gram-positive pathogens, may also function as an AI-2 membrane surface receptor in
S. suis
. In conclusion, our study demonstrated the significance of AI-2 in the synthesis of galactose metabolism-dependent CPS in
S. suis
. Additionally, we conducted a preliminary analysis of the potential role of FruA as a membrane surface receptor for
S. suis
AI-2.
Journal Article
NKLP27: A Teleost NK-Lysin Peptide that Modulates Immune Response, Induces Degradation of Bacterial DNA, and Inhibits Bacterial and Viral Infection
2014
NK-lysin is an antimicrobial protein produced by cytotoxic T lymphocytes and natural killer cells. In this study, we examined the biological property of a peptide, NKLP27, derived from tongue sole (Cynoglossus semilaevis) NK-lysin. NKLP27 is composed of 27 amino acids and shares little sequence identity with known NK-lysin peptides. NKLP27 possesses bactericidal activity against both Gram-negative and Gram-positive bacteria including common aquaculture pathogens. The bactericidal activity of NKLP27 was dependent on the C-terminal five residues, deletion of which dramatically reduced the activity of NKLP27. During its interaction with the target bacterial cells, NKLP27 destroyed cell membrane integrity, penetrated into the cytoplasm, and induced degradation of genomic DNA. In vivo study showed that administration of tongue sole with NKLP27 before bacterial and viral infection significantly reduced pathogen dissemination and replication in tissues. Further study revealed that fish administered with NKLP27 exhibited significantly upregulated expression of the immune genes including those that are known to be involved in antibacterial and antiviral defense. These results indicate that NKLP27 is a novel antimicrobial against bacterial and viral pathogens, and that the observed effect of NKLP27 on bacterial DNA and host gene expression adds new insights to the action mechanism of fish antimicrobial peptides.
Journal Article
Group B Streptococcus Sequence Type 103 as Human and Bovine Pathogen, Brazil
by
Pantoja, José Carlos F.
,
Teixeira, Lucia M.
,
Bentley, Stephen
in
Animals
,
Antimicrobial agents
,
bacteria
2024
Group B Streptococcus sequence type 103 is known primarily as a bovine mastitis pathogen. In Brazil, it has circulated in cattle and humans since the 1990s. It lacks scpB and, in humans, was found only among carriage isolates. Bovine-human interspecies transmission may have contributed to its evolution and spread.
Journal Article
Detection and prevalence of antimicrobial resistance genes in multidrug-resistant and extensively drug-resistant Staphylococcus and Streptococcus species isolated from raw buffalo milk in subclinical mastitis
by
Altaf Hossain, Ferdaus Mohd
,
Uddin, Md. Bashir
,
Rahman, Md. Masudur
in
Ampicillin
,
Animal welfare
,
Animals
2025
Subclinical mastitis (SCM) poses a significant threat to the global dairy industry, particularly in Bangladesh, where it remains a major constraint in buffalo dairy farming. The rising prevalence of antimicrobial resistant pathogens complicates disease management, resulting reduced milk yield, increased veterinary expenses, compromised animal welfare and potential risk to public health. This study investigated the prevalence and resistance profiles of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Staphylococcus and Streptococcus species in raw buffalo milk from SCM cases in Bangladesh. A total of 1,540 quarter milk samples from 385 buffaloes were analyzed, revealing SCM prevalence rates of 67.9% (1046/1540; 95% CI: 65.6–70.3) at the quarter level and 80.8% (311/385; 95% CI: 76.5–84.6) at the animal level. Notable regional variations were observed, with Gowainghat showing the highest prevalence (88.1%; 141/160). This study did not identify any biologically plausible risk factors for the occurrence of SCM in buffalo. The Modified Whiteside Test and California Mastitis Test confirmed SCM, with culture and biochemical tests identifying 789 (51.2%) Staphylococcus spp. and 424 (27.5%) Streptococcus spp. isolates. Polymerase Chain Reaction (PCR) analysis indicated that 72.7% (456/627) of Staphylococcus isolates were Staphylococcus aureus , while the predominant Streptococcus species included Streptococcus uberis (32.3%) and Streptococcus dysgalactiae (14.9%). Resistance gene detection revealed a high prevalence of antimicrobial resistant genes (ARGs), particularly aac-3(iv) and tetA, across different buffalo quarters and habitats. Antibiogram profiling demonstrated high susceptibility to tetracycline (80.9; 83.1) and trimethoprim-sulfamethoxazole (87.4; 81.9), while significant resistance was noted against ampicillin (88.8; 87.1) and nalidixic acid (68.1; 62.1). MDR was observed in 76.4% (479/627) of Staphylococcus spp. and 67.3% (167/248) of Streptococcus spp. isolates, with 10.37% (65/627) and 10.48% (26/248) classified as possible XDR, respectively. These findings explored high antimicrobial resistance level among Staphylococcus and Streptococcus species in subclinical mastitis, highlighting the need for improved management practices and surveillance to mitigate public health risks posed by contaminated milk.
Journal Article
Molecular characterization of Streptococcus suis isolates recovered from diseased pigs in Europe
by
Lacouture, Sonia
,
Lewandowski, Eric
,
Li, Kevin
in
Analysis
,
Animals
,
Anti-Bacterial Agents - pharmacology
2024
Streptococcus suis
is a major swine pathogen and zoonotic agent, causing important economic losses to the porcine industry. Here, we used genomics approaches to characterize 251
S. suis
isolates recovered from diseased pigs across Belgium, France, Germany, Hungary, the Netherlands, Spain, and the United Kingdom. We identified 13 serotypes, being serotypes 9 and 2 the most prevalent, and 34 sequence types (STs), including 16 novel STs, although ST16 and ST1 dominated the strain population. Phylogenetic analysis revealed complex genetic relationships, notable geographic clustering, and potential differential capacity for capsular switching among serotype 9 isolates. We found antimicrobial resistance (AMR) genes in 85.3% of the isolates, with high frequencies of genes conferring resistance to tetracyclines and macrolides. Specifically, 49.4% of the isolates harbored the
tetO
gene, and 64.9% possessed the
ermB
gene. Additionally, we observed a diverse array of virulence-associated genes (VAGs), including the classical VAGs
mrp
,
epf
, and
sly
, with variable presence across different genotypes. The high genetic diversity among European
S. suis
isolates highlights the importance of targeted antimicrobial use and flexible vaccine strategies. Rapid strain characterization is crucial for optimizing swine health management, enabling tailored interventions like the development of autovaccines to mitigate
S. suis
infections.
Journal Article