RESUMEN
Streptococcus mitis is a leading cause of infective endocarditis (IE). However, our understanding of the genomic epidemiology and pathogenicity of IE-associated S. mitis is hampered by low IE incidence. Here we use whole genome sequencing of 129 S. mitis bloodstream infection (BSI) isolates collected between 2001-2016 from clinically diagnosed IE cases in the UK to investigate genetic diversity, antimicrobial resistance, and pathogenicity. We show high genetic diversity of IE-associated S. mitis with virtually all isolates belonging to distinct lineages indicating no predominance of specific lineages. Additionally, we find a highly variable distribution of known pneumococcal virulence genes among the isolates, some of which are overrepresented in disease when compared to carriage strains. Our findings suggest that S. mitis in patients with clinically diagnosed IE is not primarily caused by specific hypervirulent or antimicrobial resistant lineages, highlighting the accidental pathogenic nature of S. mitis in patients with clinically diagnosed IE.
Asunto(s)
Bacteriemia , Infecciones Estreptocócicas , Streptococcus mitis , Humanos , Streptococcus mitis/genética , Streptococcus mitis/aislamiento & purificación , Reino Unido/epidemiología , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/epidemiología , Irlanda/epidemiología , Bacteriemia/microbiología , Bacteriemia/epidemiología , Endocarditis/microbiología , Endocarditis/epidemiología , Genoma Bacteriano/genética , Secuenciación Completa del Genoma , Masculino , Femenino , Variación Genética , Genómica , Anciano , Filogenia , Persona de Mediana Edad , Farmacorresistencia Bacteriana/genética , Endocarditis Bacteriana/microbiología , Endocarditis Bacteriana/epidemiología , Adulto , Factores de Virulencia/genética , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Virulencia/genéticaRESUMEN
Streptococcus suis (S. suis) is an important swine bacterial pathogen and causes human infections, leading to a wide range of diseases. However, the role of 5'-nucleotidases in its virulence remains to be fully elucidated. Herein, we identified four cell wall-anchored 5'-nucleotidases (Snts) within S. suis, named SntA, SntB, SntC, and SntD, each displaying similar domains yet exhibiting low sequence homology. The malachite green reagent and HPLC assays demonstrated that these recombinant enzymes are capable of hydrolysing ATP, ADP, and AMP into adenosine (Ado), with the hierarchy of catalytic efficiency being SntC>SntB>SntA>SntD. Moreover, comprehensive enzymatic activity assays illustrated slight variances in substrate specificity, pH tolerance, and metal ion requirements, yet highlighted a conserved substrate-binding pocket, His-Asp catalytic dyad, metal, and phosphate-binding sites across Snts, with the exception of SntA. Through bactericidal assays and murine infection assays involving in site-mutagenesis strains, it was demonstrated that SntB and SntC collaboratively enhance bacterial survivability within whole blood and polymorphonuclear leukocytes (PMNs) via the Ado-A2aR pathway in vitro, and within murine blood and organs in vivo. This suggests a direct correlation between enzymatic activity and enhancement of bacterial survival and virulence. Collectively, S. suis 5'-nucleotidases additively contribute to the generation of adenosine, influencing susceptibility within blood and PMNs, and enhancing survival within blood and organs in vivo. This elucidation of their integral functions in the pathogenic process of S. suis not only enhances our comprehension of bacterial virulence mechanisms, but also illuminates new avenues for therapeutic intervention aimed at curbing S. suis infections.
Asunto(s)
5'-Nucleotidasa , Adenosina , Modelos Animales de Enfermedad , Evasión Inmune , Infecciones Estreptocócicas , Streptococcus suis , Animales , Streptococcus suis/patogenicidad , Streptococcus suis/enzimología , Streptococcus suis/inmunología , Streptococcus suis/genética , 5'-Nucleotidasa/genética , 5'-Nucleotidasa/inmunología , 5'-Nucleotidasa/metabolismo , Ratones , Adenosina/metabolismo , Virulencia , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/inmunología , Femenino , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/inmunología , Neutrófilos/inmunología , Neutrófilos/microbiología , Ratones Endogámicos BALB C , Especificidad por SustratoRESUMEN
Streptococcus agalactiae (S. agalactiae) is an opportunistic pathogen, and to date, studies have mainly focused on S. agalactiae strains isolated from humans, dairy cows, and fish. We reported one S. agalactiae strain, named CFFB, which was isolated from a healthy Sichuan golden snub-nosed monkey. Classical bacteriological approaches, as well as, next-generation sequencing, comparative genomics, and mice challenge test were used to characterize this strain. CFFB was identified as serotype III, ST19 combination which is a common type found in human strains. Phylogenetic analysis showed that the genome of CFFB was closely related to human clinical isolates, rather far away from animal strains. In total, CFFB contained fewer virulence-associated genes and antibiotic resistance genes than human isolates that were close to CFFB in evolutionary relationships. In the mice challenge test, CFFB had a relative weak virulence that just caused death in 33 % of ICR mice at a dose of 108 CFU by intraperitoneal injection, and CFFB was reisolated from the cardiac blood of the dead mice. Meanwhile, two intact prophages (prophage 1 and 2) were identified in the CFFB genome and shared high similarities with phage Javan52 and Javan29 which from human S. agalactiae isolate Gottschalk 1002A and RBH03, respectively. Moreover, the type II-A CRISPR-Cas system was detected in the CFFB genome, and the spacers from CFFB were the same to the streptococci isolates from human. These results suggest that CFFB isolated from healthy Sichuan golden snub-nosed monkeys may have its origin in human S. agalactiae. Our results suggested some genomic similarities between the S. agalactiae colonized in Sichuan golden snub-nosed monkey and those in infected humans.
Asunto(s)
Genoma Bacteriano , Filogenia , Infecciones Estreptocócicas , Streptococcus agalactiae , Animales , Streptococcus agalactiae/genética , Streptococcus agalactiae/aislamiento & purificación , Streptococcus agalactiae/patogenicidad , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/veterinaria , China , Virulencia/genética , Ratones , Colobinae/microbiología , Humanos , Profagos/genética , Ratones Endogámicos ICR , Factores de Virulencia/genética , Serogrupo , Secuenciación de Nucleótidos de Alto Rendimiento , Enfermedades de los Monos/microbiologíaRESUMEN
BACKGROUND: Group A Streptococcus causes a variety of human infections, including the life-threatening necrotizing fasciitis, which may be ignored by the patient. From hours to days, the infection may progress from an apparently benign skin lesion, usually mistaken for a spider or insect bite, to a highly lethal disease. We present a case of 57-year-old male with skin lesions on swelling left upper limb. METHODS AND RESULTS: The culture of secretion from epidermis and blood were positive for Group A Streptococcus (GAS), type ß hemolytic streptococcus. Intensive anti-infection therapy was applied. However, the necrosis of the limb deteriorated rapidly. He died from multiple organ failure, streptococcal toxic shock syndrome (STSS) and disseminated intravascular coagulation 13 days later. CONCLUSIONS: Necrotizing fasciitis is a rapidly progressive, destructive bacterial infection. Early recognition is the most important factor for survival.
Asunto(s)
Fascitis Necrotizante , Choque Séptico , Infecciones Estreptocócicas , Streptococcus pyogenes , Fascitis Necrotizante/diagnóstico , Fascitis Necrotizante/microbiología , Humanos , Masculino , Persona de Mediana Edad , Streptococcus pyogenes/aislamiento & purificación , Infecciones Estreptocócicas/diagnóstico , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/tratamiento farmacológico , Resultado Fatal , Choque Séptico/microbiología , Choque Séptico/diagnóstico , Insuficiencia Multiorgánica/diagnóstico , Insuficiencia Multiorgánica/etiología , Insuficiencia Multiorgánica/microbiología , Antibacterianos/uso terapéutico , Coagulación Intravascular Diseminada/diagnóstico , Coagulación Intravascular Diseminada/microbiología , Coagulación Intravascular Diseminada/etiologíaRESUMEN
This case report discusses a rare instance of polymicrobial pericarditis in a man in his early 60s with a history of substance abuse. The patient presented with chest pain and shortness of breath, later diagnosed as pericarditis caused by Streptococcus anginosus, S. intermedius and Candida glabrata, likely originating from a large adjacent oesophageal ulcer. The condition led to critical illness, requiring pericardiocentesis, antibiotic and antifungal therapy. Despite initial improvement, the patient experienced recurrence and ultimately underwent pericardectomy. The article emphasises the rarity and severity of polymicrobial pericarditis, often associated with high mortality. It underscores the importance of prompt recognition, broad-spectrum antibiotics and source control, particularly when the gastrointestinal tract is implicated. The case highlights the challenges in managing such cases and the potential need for surgical intervention for optimal outcomes.
Asunto(s)
Candida glabrata , Candidiasis , Enfermedades del Esófago , Pericarditis , Úlcera , Humanos , Masculino , Pericarditis/microbiología , Pericarditis/diagnóstico , Candidiasis/complicaciones , Candidiasis/diagnóstico , Candidiasis/microbiología , Candidiasis/tratamiento farmacológico , Úlcera/microbiología , Candida glabrata/aislamiento & purificación , Enfermedades del Esófago/microbiología , Streptococcus anginosus/aislamiento & purificación , Antibacterianos/uso terapéutico , Persona de Mediana Edad , Streptococcus intermedius/aislamiento & purificación , Infecciones Estreptocócicas/complicaciones , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/diagnóstico , Infecciones Estreptocócicas/tratamiento farmacológico , Antifúngicos/uso terapéutico , Traslocación Bacteriana , Coinfección , Pericardiocentesis , PericardiectomíaRESUMEN
This study describes an outbreak of Streptococcus equi subspecies zooepidemicus infections that caused meningoencephalitis and bacteremia related to unpasteurized milk consumption in northeastern Brazil. Epidemiological investigations and a brief literature review were conducted. Strains with possible neurotropism had not been identified in Brazil before these cases; however, in 2023, another case of meningoencephalitis caused by Streptococcus equi sp. zooepidemicus was described, revealing the need to maintain surveillance and highlighting that these neurotropic strains continue to circulate in the environment.
Asunto(s)
Brotes de Enfermedades , Meningoencefalitis , Infecciones Estreptocócicas , Streptococcus equi , Meningoencefalitis/microbiología , Brasil/epidemiología , Infecciones Estreptocócicas/microbiología , Humanos , Streptococcus equi/aislamiento & purificación , Streptococcus equi/clasificación , Masculino , Animales , Femenino , Adulto , Leche/microbiología , Persona de Mediana Edad , StreptococcusRESUMEN
The recent increase in Group A Streptococcus (GAS) incidences in several countries across Europe and some areas of the Unites States (U.S.) has raised concerns. To understand GAS diversity and prevalence, we conducted a local genomic surveillance in Eastern North Carolina (ENC) in 2022-2023 with 95 isolates and compared its results to those of the existing national genomic surveillance in the U.S. in 2015-2021 with 13,064 isolates. We observed their epidemiological changes before and during the COVID-19 pandemic and detected a unique sub-lineage in ENC among the most common invasive GAS strain, ST28/emm1. We further discovered a multiple-copy insertion sequence, ISLgar5, in ST399/emm77 and its single-copy variants in some other GAS strains. We discovered ISLgar5 was linked to a Tn5801-like tetM-carrying integrative and conjugative element, and its copy number was associated with an ermT-carrying pRW35-like plasmid. The dynamic insertions of ISLgar5 may play a vital role in genome fitness and adaptation, driving GAS evolution relevant to antimicrobial resistance and potentially GAS virulence.
Asunto(s)
Infecciones Estreptocócicas , Streptococcus pyogenes , Streptococcus pyogenes/genética , Streptococcus pyogenes/patogenicidad , North Carolina/epidemiología , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/microbiología , Humanos , Genoma Bacteriano , COVID-19/epidemiología , COVID-19/virología , Genómica/métodos , Filogenia , Elementos Transponibles de ADN/genética , SARS-CoV-2/genéticaRESUMEN
In the aquatic farming industry, understanding the factors affecting fish behavior is crucial, particularly in response to infections that compromise welfare and productivity. Swimming performance is a key life history trait critical to their ecology. This study explores the swimming behavior imbalance in Nile tilapia (Oreochromis niloticus, GIFT) post-infection with Streptococcus agalactiae (GBS), a common pathogen responsible for significant losses in aquaculture. We focused on how the microbiota-gut-brain axis influences the behavioral response of tilapia to GBS infection. Behavioral changes were quantified by measuring collision times and swimming speeds, which decreased significantly following infection. This behavioral downturn is mediated by alterations in the microbiota-gut-brain axis, evidenced by increased levels of monoamine neurotransmitters (serotonin, norepinephrine, and dopamine) in the brain and intestinal tissues. The study utilized pharmacological agents, the 5-HT1A receptor agonist (8-OH-DPAT) and antagonist (WAY-100635), to investigate their efficacy in mitigating these behavioral and biochemical changes. Both agents partially restored normal behavior by adjusting neurotransmitter concentrations disrupted by GBS infection. Additionally, a notable increase in the relative abundance of Streptococcus within the gut microbiota of infected fish highlights the potential role of specific bacterial populations in influencing host behavior. This research provides novel insights into the complex interactions between pathogen-induced gut microbiota changes and Nile tilapia's behavioral outcomes, highlighting potential avenues for improving fish health management through microbiota-targeted interventions.
Asunto(s)
Conducta Animal , Cíclidos , Enfermedades de los Peces , Microbioma Gastrointestinal , Infecciones Estreptocócicas , Streptococcus agalactiae , Animales , Cíclidos/microbiología , Cíclidos/fisiología , Infecciones Estreptocócicas/veterinaria , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/fisiología , Microbioma Gastrointestinal/fisiología , Enfermedades de los Peces/microbiología , Eje Cerebro-Intestino/fisiología , Encéfalo/metabolismo , NataciónRESUMEN
The complement system is the first defense line of the immune system. However, pathogens have evolved numerous strategies to evade complement attacks. Streptococcus suis is an important zoonotic bacterium, harmful to both the pig industry and human health. ApuA has been reported as a bifunctional amylopullulanase and also contributed to virulence of S. suis. Herein, we found that ApuA could activate both classical and alternative pathways of the complement system. Furthermore, by using bacterial two-hybrid, far-western blot and ELISA assays, it was confirmed that ApuA could interact with complement C3b. The interaction domain of ApuA with C3b was found to be its α-Amylase domain (ApuA_N). After construction of an apuA mutant (ΔapuA) and its complementary strain, it was found that compared to the wild-type strain (WT), ΔapuA had significantly increased C3b deposition and membrane attack complex formation. Additionally, ΔapuA showed significantly lower survival rates in human serum and blood and was more susceptible to engulfment by neutrophils and macrophages. Mice infected with ΔapuA had significantly higher survival rates and lower bacterial loads in their blood, lung and brains, compared to those infected with WT. In summary, this study identified ApuA as a novel factor involved in the complement evasion of S. suis and suggested its multifunctional role in the pathogenesis of S. suis.
Asunto(s)
Proteínas Bacterianas , Complemento C3b , Evasión Inmune , Infecciones Estreptocócicas , Streptococcus suis , Streptococcus suis/patogenicidad , Streptococcus suis/genética , Streptococcus suis/inmunología , Streptococcus suis/enzimología , Animales , Complemento C3b/inmunología , Ratones , Infecciones Estreptocócicas/inmunología , Infecciones Estreptocócicas/veterinaria , Infecciones Estreptocócicas/microbiología , Humanos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/inmunología , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Femenino , VirulenciaRESUMEN
Group B Streptococcus (GBS) is a pathobiont responsible for invasive infections in neonates and the elderly. The transition from a commensal to an invasive pathogen relies on the timely regulation of virulence factors. In this study, we characterized the role of the SaeRS two-component system in GBS pathogenesis. Loss-of-function mutations in the SaeR response regulator decrease virulence in mouse models of invasive infection by hindering the ability of bacteria to persist at the inoculation site and to spread to distant organs. Transcriptome and in vivo analysis reveal a specialized regulatory system specifically activated during infection to control the expression of only two virulence factors: the PbsP adhesin and the BvaP secreted protein. The in vivo surge in SaeRS-regulated genes is complemented by fine-tuning mediated by the repressor of virulence CovRS system to establish a coordinated response. Constitutive activation of the SaeRS regulatory pathway increases PbsP-dependent adhesion and invasion of epithelial and endothelial barriers, though at the cost of reduced virulence. In conclusion, SaeRS is a dynamic, highly specialized regulatory system enabling GBS to express a restricted set of virulence factors that promote invasion of host barriers and allow these bacteria to persist inside the host during lethal infection. IMPORTANCE: Group B Streptococcus (or GBS) is a normal inhabitant of the human gastrointestinal and genital tracts that can also cause deadly infections in newborns and elderly people. The transition from a harmless commensal to a dangerous pathogen relies on the timely expression of bacterial molecules necessary for causing disease. In this study, we characterize the two-component system SaeRS as a key regulator of such virulence factors. Our analysis reveals a specialized regulatory system that is activated only during infection to dynamically adjust the production of two virulence factors involved in interactions with host cells. Overall, our findings highlight the critical role of SaeRS in GBS infections and suggest that targeting this system may be useful for developing new antibacterial drugs.
Asunto(s)
Proteínas Bacterianas , Regulación Bacteriana de la Expresión Génica , Infecciones Estreptocócicas , Streptococcus agalactiae , Factores de Virulencia , Streptococcus agalactiae/genética , Streptococcus agalactiae/patogenicidad , Streptococcus agalactiae/metabolismo , Infecciones Estreptocócicas/microbiología , Ratones , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Animales , Virulencia/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Modelos Animales de Enfermedad , Humanos , Adhesión Bacteriana/genética , FemeninoRESUMEN
Streptococcus pyogenes is responsible for a range of diseases in humans contributing significantly to morbidity and mortality. Among more than 200 serotypes of S. pyogenes, serotype M1 strains hold the greatest clinical relevance due to their high prevalence in severe human infections. To enhance our understanding of pathogenesis and discovery of potential therapeutic approaches, we have developed the first genome-scale metabolic model (GEM) for a serotype M1 S. pyogenes strain, which we name iYH543. The curation of iYH543 involved cross-referencing a draft GEM of S. pyogenes serotype M1 from the AGORA2 database with gene essentiality and autotrophy data obtained from transposon mutagenesis-based and growth screens. We achieved a 92.6% (503/543 genes) accuracy in predicting gene essentiality and a 95% (19/20 amino acids) accuracy in predicting amino acid auxotrophy. Additionally, Biolog Phenotype microarrays were employed to examine the growth phenotypes of S. pyogenes, which further contributed to the refinement of iYH543. Notably, iYH543 demonstrated 88% accuracy (168/190 carbon sources) in predicting growth on various sole carbon sources. Discrepancies observed between iYH543 and the actual behavior of living S. pyogenes highlighted areas of uncertainty in the current understanding of S. pyogenes metabolism. iYH543 offers novel insights and hypotheses that can guide future research efforts and ultimately inform novel therapeutic strategies.IMPORTANCEGenome-scale models (GEMs) play a crucial role in investigating bacterial metabolism, predicting the effects of inhibiting specific metabolic genes and pathways, and aiding in the identification of potential drug targets. Here, we have developed the first GEM for the S. pyogenes highly virulent serotype, M1, which we name iYH543. The iYH543 achieved high accuracy in predicting gene essentiality. We also show that the knowledge obtained by substituting actual measurement values for iYH543 helps us gain insights that connect metabolism and virulence. iYH543 will serve as a useful tool for rational drug design targeting S. pyogenes metabolism and computational screening to investigate the interplay between inhibiting virulence factor synthesis and growth.
Asunto(s)
Genoma Bacteriano , Streptococcus pyogenes , Streptococcus pyogenes/genética , Streptococcus pyogenes/metabolismo , Streptococcus pyogenes/patogenicidad , Genoma Bacteriano/genética , Humanos , Modelos Biológicos , Infecciones Estreptocócicas/microbiología , SerogrupoRESUMEN
BACKGROUND: Rheumatic heart disease (RHD) is an autoimmune disease caused by recurrent infections of Group A streptococcus (GAS), ultimately leading to inflammation and the fibrosis of heart valves. Recent studies have highlighted the crucial role of C-C chemokine receptor type 2-positive (CCR2+) macrophages in autoimmune diseases and tissue fibrosis. However, the specific involvement of CCR2+ macrophages in RHD remains unclear. METHODS: This study established an RHD rat model using inactivated GAS and complete Freund's adjuvant, demonstrating a correlation between CCR2+ macrophages and fibrosis in the mitral valves of these rats. RESULTS: Intraperitoneal injection of the CCR2 antagonist Rs-504393 significantly reduced macrophage infiltration, inflammation, and fibrosis in valve tissues of RHD rats compared to the solvent-treated group . Existing evidence suggests that C-C motif chemokine ligand 2 (CCL2) acts as the primary recruiting factor for CCR2+ cells. To validate this, human monocytic leukemia cells (THP-1) were cultured in vitro to assess the impact of recombinant CCL2 protein on macrophages. CCL2 exhibited pro-inflammatory effects similar to lipopolysaccharide (LPS), promoting M1 polarization in macrophages. Moreover, the combined effect of LPS and CCL2 was more potent than either alone. Knocking down CCR2 expression in THP-1 cells using small interfering RNA suppressed the pro-inflammatory response and M1 polarization induced by CCL2. CONCLUSIONS: The findings from this study indicate that CCR2+ macrophages are pivotal in the valvular remodeling process of RHD. Targeting the CCL2/CCR2 signaling pathway may therefore represent a promising therapeutic strategy to alleviate valve fibrosis in RHD.
Asunto(s)
Inflamación , Macrófagos , Receptores CCR2 , Cardiopatía Reumática , Animales , Humanos , Masculino , Ratas , Quimiocina CCL2/metabolismo , Quimiocina CCL2/genética , Modelos Animales de Enfermedad , Ácido Eicosapentaenoico/análogos & derivados , Fibrosis , Válvulas Cardíacas/patología , Inflamación/metabolismo , Macrófagos/metabolismo , Macrófagos/inmunología , Ratas Endogámicas Lew , Receptores CCR2/metabolismo , Receptores CCR2/genética , Cardiopatía Reumática/inmunología , Cardiopatía Reumática/microbiología , Cardiopatía Reumática/metabolismo , Cardiopatía Reumática/patología , Infecciones Estreptocócicas/inmunología , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/metabolismo , Streptococcus pyogenes , Células THP-1Asunto(s)
Bacteriemia , Infecciones Estreptocócicas , Streptococcus , Humanos , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/epidemiología , Bacteriemia/microbiología , Bacteriemia/epidemiología , Finlandia/epidemiología , Streptococcus/genética , Streptococcus/clasificación , Streptococcus/aislamiento & purificación , Masculino , Femenino , Persona de Mediana Edad , Anciano , Antibacterianos/uso terapéutico , Antibacterianos/farmacología , Índice de Severidad de la Enfermedad , AdultoRESUMEN
BACKGROUND: Streptococcus suis (S. suis) is an important swine and human pathogen. A recent study reported the first isolate of S. suis capable of infecting fish, designated as S. suis strain 3112. The bacterium was isolated from snakeskin gourami (Trichopodus pectoralis), an economically important fish species native to Southeast Asia, and it was previously shown that it can infect and cause lethal streptococcosis in the fish. RESULTS: In this study, we present the complete genome of S. suis 3112. Molecular sequence analysis revealed that it belongs to serotype 6, sequence type 2340. Phylogenetic analysis showed that the bacterium clustered with healthy-pig S. suis isolates, suggestive of an ultimate swine (as opposed to human) origin of the bacterium. Two fluoroquinolone resistance genes are present in the bacterial genome, namely patA and patB. Our results showed that both genes are expressed in our bacterium, and the bacterium is resistant to norfloxacin, but is still sensitive to other fluoroquinolones, including ciprofloxacin, enrofloxacin, and sparfloxacin. Additionally, the bacterium is sensitive to ß-lactams, tetracyclines, sulphonamides, and an aminoglycoside. CONCLUSIONS: This study reports and describes the complete genome of S. suis 3112, the first isolate of S. suis known to infect fish, and provides further insights into the bacterial isolate, particularly regarding its drug resistance profile. These results will facilitate further investigations of the comparative genomics and pathogenic characteristics of S. suis, as well as the development of control strategies against this newly-identified fish pathogen.
Asunto(s)
Genoma Bacteriano , Filogenia , Streptococcus suis , Secuenciación Completa del Genoma , Animales , Streptococcus suis/genética , Streptococcus suis/aislamiento & purificación , Streptococcus suis/efectos de los fármacos , Antibacterianos/farmacología , Infecciones Estreptocócicas/veterinaria , Infecciones Estreptocócicas/microbiología , Perciformes/microbiología , Farmacorresistencia Bacteriana/genéticaRESUMEN
Strangles, caused by Streptococcus equi subspecies equi, is a highly infectious disease of equines causing major health issues and financial losses. The aim of the study was to detect the presence of the SeM gene in Streptococcus equi isolated from equine suspected of having strangles. A cross-sectional study design was conducted from July to December 2022 in five districts of the central Gondar zone, Ethiopia. One-hundred sixty swab samples were taken from animals that had been clinically suspected. The SeM gene was detected using polymerase chain reaction, and the antimicrobial susceptibility test was performed using the Kirby-Bauer disc diffusion method. The binary logistic regression model was employed to test for statistical significance. In 31.87% (51/160) of the samples, Streptococcus equi species were isolated, and 31.37% (16/51) of these species carried the SeM gene. There was a significant amount of tetracycline (81.5%), erythromycin (81.5%), and vancomycin (75.5%) resistance among the 16 isolates. Strangles were more likely to be present in animals who shared feed containers (AOR = 7.59; 95% CI = 1.44-39.93), drank from the same water troughs (AOR = 7.74; 95% CI = 1.44-41.01), and spent the night together (AOR = 5.97; 95% CI 1.41-25.37). The findings of this study showed that the research areas harboured Streptococcus equi subspecies equi. Sharing feed containers and water troughs were potential sources of strangles infection; thus, these containers need to be cleaned regularly.
Asunto(s)
Antibacterianos , Enfermedades de los Caballos , Pruebas de Sensibilidad Microbiana , Infecciones Estreptocócicas , Animales , Caballos , Enfermedades de los Caballos/microbiología , Infecciones Estreptocócicas/veterinaria , Infecciones Estreptocócicas/microbiología , Estudios Transversales , Etiopía/epidemiología , Factores de Riesgo , Antibacterianos/farmacología , Streptococcus equi/genética , Streptococcus equi/aislamiento & purificación , Streptococcus equi/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , StreptococcusRESUMEN
BACKGROUND: Group B Streptococcus (GBS) is the leading cause of neonatal meningitis responsible for a substantial cause of death and disability worldwide. The vast majority of GBS neonatal meningitis cases are due to the CC17 hypervirulent clone. However, the cellular and molecular pathways involved in brain invasion by GBS CC17 isolates remain largely elusive. Here, we studied the specific interaction of the CC17 clone with the choroid plexus, the main component of the blood-cerebrospinal fluid (CSF) barrier. METHODS: The interaction of GBS CC17 or non-CC17 strains with choroid plexus cells was studied using an in vivo mouse model of meningitis and in vitro models of primary and transformed rodent choroid plexus epithelial cells (CPEC and Z310). In vivo interaction of GBS with the choroid plexus was assessed by microscopy. Bacterial invasion and cell barrier penetration were examined in vitro, as well as chemokines and cytokines in response to infection. RESULTS: GBS CC17 was found associated with the choroid plexus of the lateral, 3rd and 4th ventricles. Infection of choroid plexus epithelial cells revealed an efficient internalization of the bacteria into the cells with GBS CC17 displaying a greater ability to invade these cells than a non-CC17 strain. Internalization of the GBS CC17 strain involved the CC17-specific HvgA adhesin and occurred via a clathrin-dependent mechanism leading to transcellular transcytosis across the choroid plexus epithelial monolayer. CPEC infection resulted in the secretion of several chemokines, including CCL2, CCL3, CCL20, CX3CL1, and the matrix metalloproteinase MMP3, as well as immune cell infiltration. CONCLUSION: Our findings reveal a GBS strain-specific ability to infect the blood-CSF barrier, which appears to be an important site of bacterial entry and an active site of immune cell trafficking in response to infection.
Asunto(s)
Plexo Coroideo , Streptococcus agalactiae , Plexo Coroideo/metabolismo , Plexo Coroideo/microbiología , Plexo Coroideo/inmunología , Animales , Streptococcus agalactiae/patogenicidad , Ratones , Adhesinas Bacterianas/metabolismo , Virulencia , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Barrera Hematoencefálica/microbiología , Barrera Hematoencefálica/metabolismo , Modelos Animales de Enfermedad , Infecciones Estreptocócicas/metabolismo , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/inmunología , Ratones Endogámicos C57BL , Transcitosis/fisiología , FemeninoRESUMEN
The maternal pregnancy microbiome (including genitourinary and gut) has been linked to important pregnancy/birth and later childhood health outcomes. However, such sampling as part of large population cohort studies is logistically and financially challenging. Many countries routinely collect vaginal or vaginal-rectal swabs in late pregnancy for Group B Streptococcus (GBS) screening, but their utility for population-based research is still unclear. As part of planning for the Generation Victoria population-based cohort study beginning in pregnancy, we assessed the utility and reliability of residual clinical GBS vaginal/vaginal-rectal swabs for generating late pregnancy microbiome data. We carried out a two-phased pilot study. Phase one assessed the level of microbial diversity apparent in 'residual' clinical vaginal/vaginal-rectal swabs post clinical testing and storage for 7-10 days at 4 °C (routine clinical practice). Phase two directly assessed the impact of storage time and temperature on the microbial composition of vaginal/vaginal-rectal swabs collected specifically for research purposes. The microbiota composition in the 'residual' clinical swabs aligned with published studies. The 'research' swabs, stored at 4 °C for up to ten days, showed minimal changes in microbiota profile, compared to swabs examined on the day of collection. In contrast, significant variation in diversity was seen in swabs stored at room temperature for up to 48 h. Residual clinical material from swabs collected primarily for GBS screening in late pregnancy represent a reliable and abundant source of material for assessing the late pregnancy maternal microbiome for research purposes. This represents a low-burden opportunity for population-representative pregnancy studies to assess the potential of late pregnancy microbiome for prediction and understanding maternal and child health outcomes.
Asunto(s)
Microbiota , Recto , Infecciones Estreptocócicas , Streptococcus agalactiae , Vagina , Humanos , Femenino , Embarazo , Vagina/microbiología , Streptococcus agalactiae/aislamiento & purificación , Recto/microbiología , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/diagnóstico , Manejo de Especímenes/métodos , Proyectos Piloto , Adulto , Complicaciones Infecciosas del Embarazo/microbiología , Complicaciones Infecciosas del Embarazo/diagnósticoRESUMEN
The long-read sequencing platform MinION, developed by Oxford Nanopore Technologies, enables the sequencing of bacterial genomes in resource-limited settings, such as field conditions or low- and middle-income countries. For this purpose, protocols for extracting high-molecular-weight DNA using nonhazardous, inexpensive reagents and equipment are needed, and some methods have been developed for gram-negative bacteria. However, we found that without modification, these protocols are unsuitable for gram-positive Streptococcus spp., a major threat to fish farming and food security in low- and middle-income countries. Multiple approaches were evaluated, and the most effective was an extraction method using lysozyme, sodium dodecyl sulfate, and proteinase K for lysis of bacterial cells and magnetic beads for DNA recovery. We optimized the method to consistently achieve sufficient yields of pure high-molecular-weight DNA with minimal reagents and time and developed a version of the protocol which can be performed without a centrifuge or electrical power. The suitability of the method was verified by MinION sequencing and assembly of 12 genomes of epidemiologically diverse fish-pathogenic Streptococcus iniae and Streptococcus agalactiae isolates. The combination of effective high-molecular-weight DNA extraction and MinION sequencing enabled the discovery of a naturally occurring 15 kb low-copy number mobilizable plasmid in S. iniae, which we name pSI1. We expect that our resource-limited settings-adapted protocol for high-molecular-weight DNA extraction could be implemented successfully for similarly recalcitrant-to-lysis gram-positive bacteria, and it represents a method of choice for MinION-based disease diagnostics in low- and middle-income countries.
Asunto(s)
ADN Bacteriano , Secuenciación de Nanoporos , Streptococcus , Streptococcus/genética , Streptococcus/aislamiento & purificación , Streptococcus/clasificación , ADN Bacteriano/genética , Secuenciación de Nanoporos/métodos , Animales , Genoma Bacteriano/genética , Peso Molecular , Análisis de Secuencia de ADN/métodos , Peces/microbiología , Enfermedades de los Peces/microbiología , Infecciones Estreptocócicas/microbiología , Configuración de Recursos LimitadosRESUMEN
Group B Streptococcus (GBS) is a major human and animal pathogen that threatens public health and food security. Spill-over and spill-back between host species is possible due to adaptation and amplification of GBS in new niches but the evolutionary and functional mechanisms underpinning those phenomena are poorly known. Based on analysis of 1,254 curated genomes from all major GBS host species and six continents, we found that the global GBS population comprises host-generalist, host-adapted and host-restricted sublineages, which are found across host groups, preferentially within one host group, or exclusively within one host group, respectively, and show distinct levels of recombination. Strikingly, the association of GBS genomes with the three major host groups (humans, cattle, fish) is driven by a single accessory gene cluster per host, regardless of sublineage or the breadth of host spectrum. Moreover, those gene clusters are shared with other streptococcal species occupying the same niche and are functionally relevant for host tropism. Our findings demonstrate (1) the heterogeneity of genome plasticity within a bacterial species of public health importance, enabling the identification of high-risk clones; (2) the contribution of inter-species gene transmission to the evolution of GBS; and (3) the importance of considering the role of animal hosts, and the accessory gene pool associated with their microbiota, in the evolution of multi-host bacterial pathogens. Collectively, these phenomena may explain the adaptation and clonal expansion of GBS in animal reservoirs and the risk of spill-over and spill-back between animals and humans.
Asunto(s)
Genoma Bacteriano , Infecciones Estreptocócicas , Streptococcus agalactiae , Streptococcus agalactiae/genética , Streptococcus agalactiae/patogenicidad , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/genética , Animales , Humanos , Bovinos , Especificidad del Huésped/genética , Genómica , Peces/microbiología , FilogeniaRESUMEN
BACKGROUND Except for neonates, streptococci other than Streptococcus pneumoniae are a rare cause of acute bacterial meningitis. Streptococcus constellatus is a member of the Streptococcus anginosus group of gram-positive streptococci. It is a commensal microbe of the mucosae of the oral cavity, gastrointestinal tract, and urogenital tract. Rarely, it becomes pathogenic and causes contiguous or distant infections after mucosal damage. This report describes a 19-year-old immunocompetent man who developed bacterial meningitis, lung abscess, and brainstem infarct secondary to Streptococcus constellatus. CASE REPORT A 19-year-old immunocompetent man presented to the Emergency Department with a 4-week history of headache and neck pain. He was febrile on arrival. Physical examination revealed ataxia, upper-limb discoordination, and a positive Brudzinski sign. Cerebrospinal fluid and blood cultures were positive for Streptococcus constellatus, identified by matrix-assisted laser desorption ionization - time of flight mass spectrometry. Computed tomography of the chest demonstrated a lung abscess measuring 7×3.5×3 cm. A magnetic resonance imaging scan of the head revealed a 1.8×0.7 cm acute infarct in the right pons. The patient was treated initially with intravenous ceftriaxone and vancomycin before culture and sensitivity results, in addition to intravenous dexamethasone. After culture and sensitivities resulted, antibiotics were transitioned to a 4-week course of intravenous penicillin. The patient survived with no neurological consequences upon discharge. CONCLUSIONS Streptococcus constellatus should be suspected as an etiological agent for bacterial meningitis and other rare complications such as brainstem infarction and lung abscess, even in immunocompetent patients.