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1.
Mem Inst Oswaldo Cruz ; 115: e190398, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32187326

RESUMEN

BACKGROUND: Streptococcus agalactiae capsular type III strains are a leading cause of invasive neonatal infections. Many pathogens have developed mechanisms to escape from host defense response using the host membrane microdomain machinery. Lipid rafts play an important role in a variety of cellular functions and the benefit provided by interaction with lipid rafts can vary from one pathogen to another. OBJECTIVES: This study aims to evaluate the involvement of membrane microdomains during infection of human endothelial cell by S. agalactiae. METHODS: The effects of cholesterol depletion and PI3K/AKT signaling pathway activation during S. agalactiae-human umbilical vein endothelial cells (HUVEC) interaction were analysed by pre-treatment with methyl-ß-cyclodextrin (MßCD) or LY294002 inhibitors, immunofluorescence and immunoblot analysis. The involvement of lipid rafts was analysed by colocalisation of bacteria with flotillin-1 and caveolin-1 using fluorescence confocal microscopy. FINDINGS: In this work, we demonstrated the importance of the integrity of lipid rafts microdomains and activation of PI3K/Akt pathway during invasion of S. agalactiae strain to HUVEC cells. Our results suggest the involvement of flotillin-1 and caveolin-1 during the invasion of S. agalactiae strain in HUVEC cells. CONCLUSIONS: The collection of our results suggests that lipid microdomain affects the interaction of S. agalactiae type III belonging to the hypervirulent ST-17 with HUVEC cells through PI3K/Akt signaling pathway.


Asunto(s)
Células Endoteliales/virología , Lípidos de la Membrana , Microdominios de Membrana/virología , Streptococcus agalactiae/patogenicidad , Virulencia , Humanos , Recién Nacido , Streptococcus agalactiae/genética
2.
BMC Infect Dis ; 20(1): 35, 2020 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-31931732

RESUMEN

BACKGROUND: Streptococcus agalctiae (Group B Streptococcus, GBS) is a perinatal pathogen and a leading cause of neonatal infections worldwide. Serotype, sequence type, clonality, antibiotic resistance genes and surface protein profiles of GBS are scarce in Ethiopia, a reason that this study was planned to investigate. . METHODS: Sixteen colonizing GBS isolates obtained from recto-vaginal swabs of pregnant women and body surfaces of newborns were further analyzed. Minimum inhibitory concentration (MIC) test, and whole genome sequence (WGS) methods were done for antibiotic susceptibility test, and molecular characterization of the isolates. RESULTS: All the GBS isolates analyzed were belonged to four capsular serotypes: II, 11/16(68.8%), V, 3/16(18.8%), Ia and VI each with 1/16(6.3%) and five sequence type (ST-2, ST-10, ST-14, ST-569 and ST-933). Sequence type-10 was the most predominant ST followed by ST-569. The five STs were grouped into the four clonal complexes (CC - 1, CC-10, CC-19, and CC-23). Different surface proteins and pili families such as ALP1, ALPHA, ALP23, PI-1 / PI-2A1, PI-1 / PI-2B, and Srr1 were detected from WGS data. All isolates were found to be susceptible to the tested antibiotics except for tetracycline in MIC and WGS test methods used. Tetracycline resistant determinant genes such as TETM and TETL / TETM combination were identified. CONCLUSION: Further studies on serotype and molecular epidemiology will provide a comprehensive data of the GBS capsular serotype and clones available in Ethiopia.


Asunto(s)
Epidemiología Molecular/métodos , Complicaciones Infecciosas del Embarazo/epidemiología , Infecciones Estreptocócicas/epidemiología , Streptococcus agalactiae/genética , Streptococcus agalactiae/aislamiento & purificación , Antibacterianos/uso terapéutico , Farmacorresistencia Bacteriana/genética , Etiopía/epidemiología , Femenino , Hospitales Especializados , Hospitales Universitarios , Humanos , Recién Nacido , Pruebas de Sensibilidad Microbiana , Filogenia , Embarazo , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Prevalencia , Recto/microbiología , Serogrupo , Infecciones Estreptocócicas/tratamiento farmacológico , Tetraciclina/uso terapéutico , Vagina/microbiología , Secuenciación Completa del Genoma
3.
BMC Infect Dis ; 20(1): 38, 2020 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-31937247

RESUMEN

BACKGROUND: Group B Streptococcal (GBS) infections in the United States are a leading cause of meningitis and sepsis in newborns. The CDC therefore recommends GBS screening for all pregnant women at 35-37 weeks of gestation and administration of intrapartum prophylaxis (in those that tested positive) as an effective means of controlling disease transmission. Several FDA approved molecular diagnostic tests are available for rapid and accurate detection of GBS in antepartum women. METHOD: In this study, we report a clinical comparison of the Xpert GBS LB assay and a novel FDA-cleared test, Revogene GBS LB assay. A total of 250 vaginal-rectal swabs from women undergoing prenatal screening were submitted to the University of Wisconsin's clinical microbiology laboratory for GBS testing. RESULTS: We found 96.8% of samples were concordant between the two tests, while 3.2% were discordant with a positive percent agreement of 98.0% and a negative percent agreement of 96.5% between the Revogene GBS LB assay and the GeneXpert GBS LB assay. CONCLUSION: Overall, we report that both assays perform well for the detection of GBS colonization in pregnant women.


Asunto(s)
Pruebas Diagnósticas de Rutina/métodos , Tamizaje Masivo/métodos , Técnicas de Diagnóstico Molecular/métodos , Complicaciones Infecciosas del Embarazo/diagnóstico , Diagnóstico Prenatal/métodos , Infecciones Estreptocócicas/diagnóstico , Streptococcus agalactiae/genética , ADN Viral/análisis , Femenino , Técnicas Genéticas , Humanos , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Tamizaje Masivo/economía , Técnicas de Diagnóstico Molecular/economía , Embarazo , Complicaciones Infecciosas del Embarazo/virología , Mujeres Embarazadas , Infecciones Estreptocócicas/virología , Factores de Tiempo , Vagina/virología
4.
J Appl Microbiol ; 128(3): 784-793, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31651063

RESUMEN

AIMS: To develop a pcsB-based Loop-mediated isothermal amplification (LAMP) method for the detection of Streptococcus agalactiae (GBS) in milk, tilapia and vaginal swabs. METHODS AND RESULTS: The sensitivity of the LAMP method using real-time turbidity monitoring was 1 pg of template within 1 h at 64°C, 100-fold higher than conventional PCR. The sensitivity of visual detection dropped an order of magnitude using SYBR Green I or hydroxynaphthol blue. The validity of the visual LAMP assay was assessed by the detection of GBS in 180 vaginal swabs from one hospital, 14 brain tissues samples of diseased tilapias from two fishponds and fresh milk of 67 dairy cattle from one farm. In total, 17 samples (4 vaginal swabs, 13 tilapia brain tissues but no milk sample) tested positive for GBS. Subsequent bacterial identification confirmed the specificity and reliability of the LAMP method. Molecular serotyping and multilocus sequence typing demonstrated that all 13 tilapia GBS isolates were identical (serotype Ia, ST7), whereas the four human GBS isolates were more diverse and could be classified into two serotypes (Ia, III) and four sequence types (ST19, ST23, ST24, ST862). Virulence gene testing showed that only the bac, rib and lmb genes were not present in all isolates. Antimicrobial susceptibility profiles of the isolates were basically consistent with their genotypes, except for sulphonamide and fluoroquinolone. CONCLUSIONS: We developed a reliable pcsB-based LAMP assay for GBS detection. Our results demonstrated that the prevalence of GBS was 92·9% among diseased tilapia, 2·2% among female patients and 0% on a dairy farm in Hainan. SIGNIFICANCE AND IMPACT OF THE STUDY: The pcsB-based LAMP method is suitable for GBS detection and contains great potential of application in dairy industry, aquiculture and clinical.


Asunto(s)
Proteínas Bacterianas/genética , Proteínas de Ciclo Celular/genética , Técnicas de Amplificación de Ácido Nucleico/métodos , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/aislamiento & purificación , Animales , Antibacterianos/farmacología , Técnicas de Tipificación Bacteriana , China , Femenino , Genotipo , Humanos , Pruebas de Sensibilidad Microbiana , Leche/microbiología , Tipificación de Secuencias Multilocus , Reproducibilidad de los Resultados , Serogrupo , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/efectos de los fármacos , Streptococcus agalactiae/genética , Tilapia/microbiología , Vagina/microbiología , Virulencia/genética
5.
BMC Infect Dis ; 19(1): 1009, 2019 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-31779587

RESUMEN

BACKGROUND: Although Streptococcus agalactiae is the leading causative agent of neonatal sepsis and meningitis, recently it is increasingly isolated from non-pregnant adults. The relation between its presence in the genitourinary tract and manifested clinical symptoms of STD patients remains an open question. In this study, a complex epidemiological investigation of GBS isolates from a venerology clinic was performed. METHODS: Ninety-six GBS isolates were serotyped and their genetic relatedness determined by PFGE. MLST was also performed for a subset of 20 isolates. The antibiotic susceptibility was tested with agar dilution. Surface proteins and the ST-17 hypervirulent clone was detected by PCR. RESULTS: The serotype prevalence was the following: V (29.2%), III (27.1%), Ia (22.9%), IV (10.4%), II (5.2%) and Ib (4.2%). A strong association was demonstrated between surface protein genes and serotypes. All isolates were fully susceptible to penicillin, but erythromycin and clindamycin resistance was high (41.7 and 35.4%, respectively), and 8 phenotypically macrolide sensitive isolates carried the ermB gene. 21.9% of all strains belonged to the hypervirulent ST17 clone, most being of serotype III and all were rib +. We found a few serotype IV isolates belonging to several STs and one serotype V/ST110 strain, containing a 44-bp deletion in the atr allele. CONCLUSIONS: The presence of silent ermB genes is of worry, as their expression upon macrolide exposure could lead to unforeseen therapeutic failure, while clindamycin is used for intrapartum antibiotic prophylaxis, in case of penicillin allergy. The other alarming result is the high prevalence of ST17 among these strains from STD patients, who could be sources of further infections. This is the first report from Hungary providing both serotyping and genotyping data of GBS isolates. These results could be helpful for vaccine production as the major vaccine candidates are capsular antigens or surface proteins.


Asunto(s)
Infecciones Estreptocócicas/diagnóstico , Streptococcus agalactiae/genética , Adulto , Antibacterianos/farmacología , Proteínas Bacterianas/genética , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Farmacorresistencia Bacteriana/efectos de los fármacos , Femenino , Humanos , Hungría/epidemiología , Macrólidos/farmacología , Pruebas de Sensibilidad Microbiana , Fenotipo , Prevalencia , Serogrupo , Infecciones Estreptocócicas/epidemiología , Streptococcus agalactiae/efectos de los fármacos , Streptococcus agalactiae/aislamiento & purificación , Streptococcus agalactiae/patogenicidad , Virulencia/genética
6.
BMC Genomics ; 20(1): 886, 2019 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-31752672

RESUMEN

BACKGROUND: The genome topology network (GTN) is a new approach for studying the phylogenetics of bacterial genomes by analysing their gene order. The previous GTN tool gives a phylogenetic tree and calculate the different degrees (DD) of various adjacent gene families with complete genome data, but it is limited to the gene family level. RESULT: In this study, we collected 51 published complete and draft group B Streptococcus (GBS) genomes from the NCBI database as the case study data. The phylogenetic tree obtained from the GTN method assigned the genomes into six main clades. Compared with single nucleotide polymorphism (SNP)-based method, the GTN method exhibited a higher resolution in two clades. The gene families located at unique node connections in these clades were associated with the clusters of orthologous groups (COG) functional categories of "[G] Carbohydrate transport and metabolism,", "[L] Replication, recombination, and repair" and "[J] translation, ribosomal structure and biogenesis". Thus, these genes were the major factors affecting the differentiation of these six clades in the phylogenetic tree obtained from the GTN. CONCLUSION: The modified GTN analyzes draft genomic data and exhibits greater functionality than the previous version. The gene family clustering algorithm embedded in the GTN tool is optimized by introducing the Markov cluster algorithm (MCL) tool to assign genes to functional gene families. A bootstrap test is performed to verify the credibility of the clades when allowing users to adjust the relationships of the clades accordingly. The GTN tool gives additional evolutionary information that is a useful complement to the SNP-based method. Information on the differences in the connections between a gene and its adjacent genes in species or clades is easily obtained. The modified GTN tool can be downloaded from https://github.com/0232/Genome_topology_network.


Asunto(s)
Genoma Bacteriano , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/genética , Orden Génico , Filogenia , Polimorfismo de Nucleótido Simple
7.
PLoS One ; 14(10): e0223256, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31577825

RESUMEN

As a leading cause of neonatal sepsis, Streptococcus agalactiae, commonly known as Group B Streptococcus, is a major neonatal pathogen. Current global screening practices employ risk- or culture-based protocols for detection of these organisms. In Western Australia (WA), universal culture-based screening is provided, with subsequent intrapartum antibiotic prophylaxis for all S. agalactiae-positive women during labour. Widespread antibiotic exposure is not ideal and this is one of the factors driving development of vaccines against S. agalactiae. Vaccine candidates have focused on the capsule, surface proteins and pilus types, however, capsule serotypes are known to vary geographically. The aim of this study was to use genome sequencing to gain an understanding of the circulating genotypes in WA, and to assess variations in the associated gene pools. We sequenced 141 antenatal carriage (vaginal/rectal) isolates and 10 neonatal invasive disease isolates from WA. Based on the global PubMLST database, the 151 strains were characterised into 30 sequence types, with clustering of these mainly into clonal complexes 1, 12, 17, 19 and 23. Of the genes encoding eleven surface proteins that were analysed, the most prevalent were fbp, lmb and scpB which were present in ≥ 98% of isolates. A cluster of non-haemolytic isolates, one of which was a neonatal invasive disease isolate, appeared to lack the entire cyl locus. Admixture analysis of population structure revealed evidence of genetic transfer among the WA isolates across structural groups. When compared against the PubMLST S. agalactiae data, WA isolates showed high levels of strain diversity with minimal apparent clustering. This is the first whole genome sequence study of WA S. agalactiae isolates and also represents the first addition of Australian isolate data to PubMLST. This report provides insight into the distribution and diversity of vaccine targets of S. agalactiae within Western Australia, indicating that the most appropriate capsular vaccine for this population would be the proposed pentavalent (Cps Ia, Ib, II, III and V) preparation, whilst vaccines targeting surface proteins should ideally utilise Fbp, Lmb and/or ScpB.


Asunto(s)
Genoma Bacteriano , Atención Perinatal , Streptococcus agalactiae/genética , Streptococcus agalactiae/aislamiento & purificación , Genes Bacterianos , Humanos , Funciones de Verosimilitud , Filogenia , Streptococcus agalactiae/patogenicidad , Virulencia/genética , Australia Occidental
8.
Emerg Infect Dis ; 25(11): 2021-2030, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31600132

RESUMEN

Invasive group B Streptococcus (GBS) remains a leading cause of illness and death among infants globally. We conducted prospective and retrospective laboratory-based surveillance of GBS-positive cultures from infants <3 months of age in 18 hospitals across China during January 1, 2015-December 31, 2017. The overall incidence of GBS was 0.31 (95% CI 0.27-0.36) cases/1,000 live births; incidence was 0-0.76 cases/1,000 live births across participating hospitals. The case-fatality rate was 2.3%. We estimated 13,604 cases of GBS and 1,142 GBS-associated deaths in infants <90 days of age annually in China. GBS isolates were most commonly serotype III (61.5%) and clonal complex 17 (40.6%). Enhanced active surveillance and implementation of preventive strategies, such as maternal GBS vaccination, warrants further investigation in China to help prevent these infections.


Asunto(s)
Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/genética , Edad de Inicio , Preescolar , China/epidemiología , Geografía Médica , Humanos , Incidencia , Lactante , Recién Nacido , Epidemiología Molecular , Tipificación Molecular , Vigilancia en Salud Pública , Serotipificación
9.
Biofouling ; 35(8): 938-944, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31646898

RESUMEN

Streptococcus agalactiae (group B Streptococcus, GBS) is a major pathogen in humans and animals. Pili and biofilm may be important virulence factors in this bacterial species. Here, biofilm production and the distribution of pilus variants among 134 GBS isolates from human and animal sources were evaluated. Biofilm production was significantly enhanced in 1% glucose-supplemented medium (p < 0.05). Using this medium, most GBS strains were strong biofilm producers. Biomass was mainly composed of proteins, followed by extracellular DNA, while polysaccharides represented a minor portion. All GBS strains presented at least one pilus variant. PI-2a was the most common among human GBS while PI-2b was the most common among animal isolates. Human GBS harboring PI-2b and animal GBS harboring PI-2a presented significantly reduced biofilm production (p = 0.0033). In conclusion, strong biofilm production seems to be a common characteristic in GBS, and association of the clinical source with the pilus variant may be crucial for this.


Asunto(s)
Biopelículas/crecimiento & desarrollo , Fimbrias Bacterianas/genética , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/aislamiento & purificación , Animales , Proteínas Bacterianas/genética , ADN Bacteriano , Variación Genética , Humanos , Streptococcus agalactiae/genética , Streptococcus agalactiae/crecimiento & desarrollo , Factores de Virulencia/genética
10.
PLoS One ; 14(9): e0222910, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31536604

RESUMEN

Group B Streptococcus (GBS) is an opportunistic pathogen that causes preterm birth and neonatal disease. Although GBS is known to exhibit vast diversity in virulence across strains, the mechanisms of GBS-associated pathogenesis are incompletely understood. We hypothesized that GBS strains of different genotypes would vary in their ability to elicit host inflammatory responses, and that strains associated with neonatal disease would induce different cytokine profiles than those associated with colonization. Using a multiplexed, antibody-based protein detection array, we found that production of a discrete number of inflammatory mediators by THP-1 macrophage-like cells was universally induced in response to challenge with each of five genetically distinct GBS isolates, while other responses appeared to be strain-specific. Key array responses were validated by ELISA using the initial five strains as well as ten additional strains with distinct genotypic and phenotypic characteristics. Interestingly, IL-6 was significantly elevated following infection with neonatal infection-associated sequence type (ST)-17 strains and among strains possessing capsule (cps) type III. Significant differences in production of IL1-ß, IL-10 and MCP-2 were also identified across STs and cps types. These data support our hypothesis and suggest that unique host innate immune responses reflect strain-specific differences in virulence across GBS isolates. Such data might inform the development of improved diagnostic or prognostic strategies against invasive GBS infections.


Asunto(s)
Citocinas/inmunología , Mediadores de Inflamación/inmunología , Macrófagos/inmunología , Infecciones Estreptocócicas/inmunología , Streptococcus agalactiae/genética , Citocinas/metabolismo , Genotipo , Interacciones Huésped-Patógeno , Humanos , Inmunidad Innata/inmunología , Mediadores de Inflamación/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiología , Especificidad de la Especie , Infecciones Estreptocócicas/metabolismo , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/patogenicidad , Células THP-1 , Virulencia/genética
11.
BMC Infect Dis ; 19(1): 812, 2019 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-31533652

RESUMEN

BACKGROUND: Invasive group B Streptococcus (GBS) disease in Chinese infants has gradually gained attention in recent years, but the molecular epidemiology of the pathogen is still not well known. METHODS: This multicenter study retrospectively investigated distribution of capsular serotypes, sequence types (STs), and hypervirulent GBS adhesin gene (hvgA) in clinical GBS isolates that caused invasive disease in infants aged < 3 months of age in southern mainland China between January 2013 and June 2016. Genes for antibiotic resistance to tetracycline, erythromycin, and clindamycin were also examined. RESULTS: From a total of 93 GBS isolates taken from 34 early-onset disease (EOD, 0-6 days after birth) and 59 late-onset disease (LOD, 7-89 days after birth) cases, four serotypes were identified: serotypes III (79.6%), Ib (12.9%), Ia (4.3%), and V (3.2%). Serotype III accounted for 73.5% of EOD and 83.1% of LOD and was responsible for 75.5% of cases involving meningitis. Fifteen STs were found, with the majority being ST17 (61.3%), ST12 (7.5%), ST19 (7.5%), and others (23.7%). 96.8% of STs belonged to only five clonal complexes (CCs): CC17 (64.5%), CC10 (12.9%), CC19 (9.7%), CC23 (6.5%), and CC1 (3.2%). The hvgA gene was detected in 66.7% of GBS isolates and 95% of CC17 isolates, all of which were serotype III except one serotype Ib/CC17 isolate. A large proportion of GBS isolates were found to be resistant to tetracycline (93.5%), clindamycin (65.5%), and erythromycin (60.2%). Genes of tetO (74.7%) and tetM (46.0%) were found in tetracycline resistant isolates, linB (24.6%) in clindamycin resistant isolates, and ermB (87.5%) and mefA (3.6%) in erythromycin resistant isolates. CONCLUSION: Our results reveal higher prevalence of serotype III, ST17, CC17, hvgA expressing, and antibiotic resistant GBS isolates than previously reported in southern mainland China. This study provides guidance for appropriate measures of prevention and control to be taken in the future.


Asunto(s)
Infecciones Estreptocócicas/diagnóstico , Streptococcus agalactiae/aislamiento & purificación , Adhesinas Bacterianas/genética , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , China/epidemiología , ADN Bacteriano/química , ADN Bacteriano/metabolismo , Farmacorresistencia Bacteriana/efectos de los fármacos , Humanos , Lactante , Recién Nacido , Tipificación de Secuencias Multilocus , Prevalencia , Estudios Retrospectivos , Serogrupo , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/patología , Streptococcus agalactiae/genética
12.
Gene ; 720: 144094, 2019 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-31476407

RESUMEN

Fourteen different insertion sequences belonging to seven families were identified in the genome of Streptococcus agalactiae. Among them, IS1548, a mobile element of the ISAs1 family, was linked to clonal complex (CC) 19 strains associated with neonatal meningitis and endocarditis. IS1548 impacts S. agalactiae in two reported ways: i) inactivation of virulence genes by insertion in an open reading frame (e.g. hylB or cpsD), ii) positive modulation of the expression of a downstream gene by insertion in an intergenic region (e.g. lmb). We previously identified an unknown integration site of IS1548 in the intergenic region between the folK and the murB genes involved in folate and peptidoglycan biosynthesis, respectively. In this work, we analyzed the prevalence of IS1548 in a large collection of nine hundred and eleven S. agalactiae strains. IS1548 positive strains belong to twenty-nine different sequence types and to ten CCs. The majority of them were, however, clustered within sequence type 19 and sequence type 22, belonging to CC19 and CC22, respectively. In contrast, IS1548 targets the folK-murB intergenic region exclusively in CC19 strains. We evaluated the impact of the insertion of IS1548 on the expression of murB by locating transcriptional promoters influencing its expression in the presence or absence of IS1548 and by comparative ß-galactosidase transcriptional fusion assays. We found that in the absence of IS1548, genes involved in folate biosynthesis are co-transcribed with murB. As it was postulated that a folic acid mediated reaction may be involved in cell wall synthesis, this co-transcription could be necessary to synchronize these two processes. The insertion of IS1548 in the folK-murB intergenic region disrupt this co-transcription. Interestingly, we located a promoter at the right end of IS1548 that is able to initiate additional transcripts of murB. The insertion of IS1548 in this region has thus a dual and divergent impact on the expression of murB. By comparative ß-galactosidase transcriptional fusion assays, we showed that, consequently, the overall impact of the insertion of IS1548 results in a minor decrease of murB gene transcription. This study provides new insights into gene expression effects mediated by IS1548 in S. agalactiae.


Asunto(s)
Proteínas Bacterianas/genética , ADN Intergénico , Regulación Bacteriana de la Expresión Génica , Secuencias Repetitivas Esparcidas , Mutagénesis Insercional , Peptidoglicano/biosíntesis , Streptococcus agalactiae/genética , Proteínas Bacterianas/metabolismo , Secuencia de Bases , ADN Bacteriano/genética , Regiones Promotoras Genéticas , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/crecimiento & desarrollo , Streptococcus agalactiae/metabolismo
13.
Braz J Microbiol ; 50(4): 943-952, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31432465

RESUMEN

Brazilian data for maternal GBS colonization shows different prevalence rates. This conflicting data may be related to the absence of an official recommendation from the Federal Brazilian Health Authorities describing guidelines and protocols to perform GBS screening in pregnant women, in both public and private clinics. In the present review, we evaluated published reports addressing the prevalence of GBS in different regions of the country, methods used, and, when available, information regarding antibiotic resistance and serological typing of clinical isolates. According to this review, GBS prevalence in pregnant women in Brazil ranged from 4.2 to 28.4%, in the last 10 years. Serotype Ia was the most prevalent. The highest antibiotic resistance rates were found for tetarcycline, although its use to treat GBS infections is not common. Our results also show high resistance rates to clindamycin and erythromycin, which are commonly used as an alternative to penicillin in GBS infecctions. The increased antibiotic resistance, variations in serotype distribution, and high GBS prevalences need to be further investigated. Based on the present situation, recommendations regarding GBS surveillance in the country were raised and may improve our strategies for preventing neonatal infections.


Asunto(s)
Farmacorresistencia Bacteriana , Complicaciones Infecciosas del Embarazo/microbiología , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/aislamiento & purificación , Antibacterianos/farmacología , Brasil/epidemiología , Femenino , Humanos , Embarazo , Complicaciones Infecciosas del Embarazo/epidemiología , Serogrupo , Infecciones Estreptocócicas/epidemiología , Streptococcus agalactiae/clasificación , Streptococcus agalactiae/efectos de los fármacos , Streptococcus agalactiae/genética
14.
BMC Res Notes ; 12(1): 437, 2019 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-31324269

RESUMEN

OBJECTIVES: Group B Streptococcus (GBS) is an important opportunistic bacteria that causes a wide range of infections including neonatal sepsis, meningitis, pneumonia, soft tissue and urinary tract infections (UTI). The aim of this study was to evaluate the antimicrobial susceptibility patterns, surface proteins and capsular types of GBS isolates. RESULTS: 100 of UTI isolates were confirmed as GBS. Antimicrobial susceptibility pattern showed that 95% of GBS isolates were resistant to tetracycline, followed by erythromycin (52%), clindamycin (47%), levofloxacin (9%) and penicillin, cefepime, cefotaxime, and ceftriaxone each with (8%), and vancomycin 1%. Common capsular types were III, Ib, V, II, Ia and IV respectively and the distribution of surface protein genes was as follows: rib (40%), alpha-c (22%), alp2/3 (18%) and epsilon (15%), and alp4 gene was not detected in the isolates. Our findings showed the relationship between capsular types with Alpha-like proteins, as well as reduced sensitivity to antibiotics, so the performance of antibiotic surveillance programs is recommended.


Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas de la Membrana/metabolismo , Proteoma/metabolismo , Streptococcus agalactiae/metabolismo , Antibacterianos/clasificación , Antibacterianos/farmacología , Cápsulas Bacterianas/genética , Cápsulas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Genotipo , Humanos , Irán , Lipopolisacáridos/metabolismo , Proteínas de la Membrana/genética , Pruebas de Sensibilidad Microbiana , Proteoma/genética , Proteómica/métodos , Serotipificación , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/genética , Streptococcus agalactiae/fisiología , Infecciones Urinarias/microbiología
15.
Jpn J Infect Dis ; 72(6): 420-422, 2019 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-31257242

RESUMEN

Streptococcus agalactiae (Group B Streptococcus, GBS) is a pathogen which causes neo natal sepsis, meningitis, and invasive infections in the elderly and people with medical conditions. Macrolide and lincosamide resistance rates of GBS strains have been increasing worldwide. A macrolide resistance gene, erythromycin ribosomal methylase (erm), typically confers macrolides, lincosamides, streptogramin B resistance phenotype. However, in the current study, we recovered and characterized 3 clinical ermB-PCR-positive isolates of GBS with L phenotype. The presence of ermB and lnuB (lincosamide nucleotidyltransferase) genes in all 3 clinical isolates was confirmed using PCR. The ermB gene of the clinical isolates harbored C222T (N74N), T224C (I75T), and A299G (N100S) nucleotide (amino acid) substitutions, and insertion of an IS1216E element at nucleotide position 643, resulted in the deletion of a segment spanning nucleotides 643-738 of ermB gene, which suggested the loss-of-function of ErmB protein in the 3 clinical isolates. Since these clinical isolates show positive PCR result for a drug resistance gene despite its partial deletion, these results contradict their drug resistance phenotype. These factors must be considered while performing PCR-based detection of antimicrobial drug resistance genes.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/genética , Clindamicina/farmacología , Eritromicina/farmacología , Streptococcus agalactiae/efectos de los fármacos , Streptococcus agalactiae/genética , Farmacorresistencia Bacteriana/genética , Humanos , Pruebas de Sensibilidad Microbiana , Fenotipo , Infecciones Estreptocócicas/microbiología
16.
Vet Microbiol ; 235: 71-79, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31282381

RESUMEN

Streptococcus agalactiae (Group B streptococcus, GBS) is a commensal of the human intestinal tract and vagina and is also an opportunistic pathogen causing serious, potentially lethal, infections preferentially in newborns and in the elderly. In cattle, it is considered an udder-specific pathogen and a common cause of mastitis. Here we investigated the host specificity of GBS by examining their colonization at various anatomical sites in both cattle and humans, as well as the possible cross-species transmission in closed barn environments. We collected more than 800 swab samples from dairy cows and herdspersons at eight dairy farms in Denmark. GBS was isolated from 12% of the samples. The GBS strains (N = 105) were characterized by biochemical test, serology, and Pulsed-Field Gel Electrophoresis (PFGE). Based on the PFGE patterns, 25 strains were selected for whole genome sequencing followed by phylogenetic analyses. The genomes were compared to each other and to a collection of publicly available GBS genomes. The study revealed that GBS clones were shared by cows and herdspersons. In phylogenetic analyses, these shared clones clustered with GBS strains from persons with no relation to farming. Horizontal cross-species transmission of the contagion in both directions was found to be highly likely within the same environment; thus, some cases of bovine mastitis are probably antrophonotic.


Asunto(s)
Bovinos/microbiología , Agricultores , Especificidad del Huésped , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/genética , Animales , Industria Lechera , Dinamarca , Reservorios de Enfermedades/microbiología , Femenino , Humanos , Masculino , Mastitis Bovina/microbiología , Leche/microbiología , Faringe/microbiología , Filogenia , Recto/microbiología , Infecciones Estreptocócicas/transmisión , Streptococcus agalactiae/aislamiento & purificación , Vagina/microbiología
17.
PLoS Pathog ; 15(6): e1007848, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-31181121

RESUMEN

Streptococcus agalactiae (Group B Streptococcus, GBS) normally colonizes healthy adults but can cause invasive disease, such as meningitis, in the newborn. To gain access to the central nervous system, GBS must interact with and penetrate brain or meningeal blood vessels; however, the exact mechanisms are still being elucidated. Here, we investigate the contribution of BspC, an antigen I/II family adhesin, to the pathogenesis of GBS meningitis. Disruption of the bspC gene reduced GBS adherence to human cerebral microvascular endothelial cells (hCMEC), while heterologous expression of BspC in non-adherent Lactococcus lactis conferred bacterial attachment. In a murine model of hematogenous meningitis, mice infected with ΔbspC mutants exhibited lower mortality as well as decreased brain bacterial counts and inflammatory infiltrate compared to mice infected with WT GBS strains. Further, BspC was both necessary and sufficient to induce neutrophil chemokine expression. We determined that BspC interacts with the host cytoskeleton component vimentin and confirmed this interaction using a bacterial two-hybrid assay, microscale thermophoresis, immunofluorescent staining, and imaging flow cytometry. Vimentin null mice were protected from WT GBS infection and also exhibited less inflammatory cytokine production in brain tissue. These results suggest that BspC and the vimentin interaction is critical for the pathogenesis of GBS meningitis.


Asunto(s)
Antígenos Bacterianos/metabolismo , Proteínas Bacterianas/metabolismo , Encéfalo/metabolismo , Meningitis Bacterianas/metabolismo , Infecciones Estreptocócicas/metabolismo , Streptococcus agalactiae/metabolismo , Vimentina/metabolismo , Animales , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Encéfalo/irrigación sanguínea , Encéfalo/microbiología , Encéfalo/patología , Endotelio Vascular , Células HeLa , Humanos , Masculino , Meningitis Bacterianas/genética , Meningitis Bacterianas/patología , Ratones , Ratones Mutantes , Ovinos , Infecciones Estreptocócicas/genética , Infecciones Estreptocócicas/patología , Streptococcus agalactiae/genética , Streptococcus agalactiae/patogenicidad , Vimentina/genética
18.
Artículo en Inglés | MEDLINE | ID: mdl-31192160

RESUMEN

Group B Streptococcus (GBS) is a major cause of invasive disease in neonates worldwide. Monitoring data have revealed a continuing trend toward an increase in neonatal GBS infections, despite the introduction of preventive measures. We investigated this trend, by performing the first ever characterization of the prophage content for 106 GBS strains causing neonatal infections between 2002 and 2018. We determined whether the genome of each strain harbored prophages, and identified the insertion site of each of the prophages identified. We found that 71.7% of the strains carried at least one prophage, and that prophages genetically similar to livestock-associated phiD12, carrying genes potentially involved in GBS pathogenesis (e.g., genes encoding putative virulence factors and factors involved in biofilm formation, bacterial persistence, or adaptation to challenging environments) predominated. The phiD12-like prophages were (1) associated with CC17 and 1 strains (p = 0.002), (2) more frequent among strains recovered during the 2011-2018 period than among those from 2002-2010 (p < 0.001), and (3) located at two major insertion sites close to bacterial genes involved in host adaptation and colonization. Our data provide evidence for a recent increase in lysogeny in GBS, characterized by the acquisition, within the genome, of genetic features typical of animal-associated mobile genetic elements by GBS strains causing neonatal infection. We suggest that lysogeny and phiD12-like prophage genetic elements may have conferred an advantage on GBS strains for adaptation to or colonization of the maternal vaginal tract, or for pathogenicity, and that these factors are currently playing a key role in the increasing ability of GBS strains to infect neonates.


Asunto(s)
Ganado/virología , Profagos/genética , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/genética , Streptococcus agalactiae/virología , Adaptación Fisiológica , Animales , Femenino , Genoma Bacteriano , Humanos , Recién Nacido , Lisogenia , Mutagénesis Insercional , Streptococcus agalactiae/fisiología , Virulencia/genética , Virulencia/fisiología , Factores de Virulencia/genética , Factores de Virulencia/fisiología
19.
J Appl Microbiol ; 127(2): 598-604, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31120589

RESUMEN

AIM: Global screening strategies for Group B Streptococcus (GBS) include risk- or culture-based methods to guide intrapartum prophylaxis. In Western Australia (WA), antenatal culture-based screening is routine; however, numerous culture methods exist, in addition to molecular methods. We aimed to assess the comparability of research and diagnostic screening approaches. METHODS AND RESULTS: Vaginal and rectal swabs were self-collected by pregnant women (n = 531) from King Edward Memorial Hospital, WA, in parallel to routine screening (35-37 weeks of gestation). Research methods involved culture (Strep B Carrot Broth™ and StrepB CHROMagar™) and molecular methods (real-time PCR) and were compared to routine diagnostic screening (Lim Broth and Granada agar). Overall, GBS detection was comparable between research and diagnostic approaches (3-5% discrepancy, kappa = 0·76). Specificity/sensitivity of Carrot Broth™ was 100%/89%, while that of CHROMagar™ was 73%/100%, respectively. Direct PCR was unable to detect GBS in ~18% of specimens which were culture positive; however, it exhibited 100% specificity. CONCLUSIONS: This clinical evaluation of GBS screening methods provides support for current practice. SIGNIFICANCE AND IMPACT OF THE STUDY: Although CHROM was highly sensitive, further testing is recommended due to a high false-positive rate. Molecular assays are useful for rapid detection; however, low-titre samples may require additional enrichment prior to molecular analysis to improve sensitivity.


Asunto(s)
Complicaciones Infecciosas del Embarazo/diagnóstico , Diagnóstico Prenatal , Infecciones Estreptocócicas/diagnóstico por imagen , Streptococcus agalactiae/aislamiento & purificación , Femenino , Humanos , Embarazo , Reacción en Cadena en Tiempo Real de la Polimerasa , Recto/microbiología , Sensibilidad y Especificidad , Infecciones Estreptocócicas/diagnóstico , Streptococcus agalactiae/genética , Vagina/microbiología , Australia Occidental
20.
PLoS One ; 14(4): e0214077, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30970036

RESUMEN

BACKGROUND: Globally, over 400,000 neonatal deaths in 2015 were attributed to sepsis, however, the incidence and etiologies of these infections are largely unknown in low-middle income countries. We aimed to determine incidence and etiology of community-acquired early-onset (<72 hours age) sepsis (EOS) using culture and molecular diagnostics. METHODS: This was a prospective observational study, in which we conducted a surveillance for pathogens using a combination of blood culture and a polymerase chain reaction (PCR)-based test. Blood culture was performed on all neonates with suspected EOS. Among the subset fulfilling criteria for protocol-defined EOS, blood and nasopharyngeal (NP) respiratory swabs were tested by quantitative real-time reverse-transcriptase PCR using a Taqman Array Card (TAC) with 15 bacterial and 12 viral targets. Blood and NP samples from 312 healthy newborns were also tested by TAC to estimate background positivity rates. We used variant latent-class methods to attribute etiologies and calculate pathogen-specific proportions and incidence rates. RESULTS: We enrolled 2,624 neonates with suspected EOS and from these 1,231 newborns met criteria for protocol-defined EOS (incidence- 39.3/1,000 live-births). Using the partially latent-class modelling, only 26.7% cases with protocol-defined EOS had attributable etiology, and the largest pathogen proportion were Ureaplasma spp. (5.4%; 95%CI: 3.6-8.0) and group B Streptococcus (GBS) (4.8%; 95%CI: 4.1-5.8), and no etiology was attributable for 73.3% of cases. Blood cultures were positive in 99/1,231 (8.0%) with protocol-defined EOS (incidence- 3.2/1,000 live-births). Leading pathogens on blood culture included GBS (35%) and viridans streptococci (24%). Ureaplasma spp. was the most common organism identified on TAC among cases with protocol-defined EOS. CONCLUSION: Using a combination of blood culture and a PCR-based test the common pathogens isolated in neonates with sepsis were Ureaplasma spp. and GBS. Despite documenting higher rates of protocol-defined EOS and using a combination of tests, the etiology for EOS remains elusive.


Asunto(s)
Sepsis Neonatal/sangre , Complicaciones Infecciosas del Embarazo/sangre , Infecciones Estreptocócicas/sangre , Streptococcus agalactiae/aislamiento & purificación , Edad de Inicio , Cultivo de Sangre , Femenino , Humanos , Recién Nacido , Sepsis Neonatal/epidemiología , Sepsis Neonatal/microbiología , Sepsis Neonatal/patología , Embarazo , Complicaciones Infecciosas del Embarazo/epidemiología , Complicaciones Infecciosas del Embarazo/microbiología , Complicaciones Infecciosas del Embarazo/patología , Sudáfrica , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/patología , Streptococcus agalactiae/genética , Streptococcus agalactiae/patogenicidad , Ureaplasma/aislamiento & purificación , Ureaplasma/patogenicidad
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