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Sample records for streptococcus agalactiae gbs

  1. The homodimeric GBS1074 from Streptococcus agalactiae

    International Nuclear Information System (INIS)

    Shukla, Anshuman; Pallen, Mark; Anthony, Mark; White, Scott A.

    2010-01-01

    The homodimeric nature of the ESAT-6 homologue GBS1074 and the potential for fibre-like assemblies are revealed by the 2 Å resolution crystal structure. ESAT-6 is a well characterized secreted protein from Mycobacterium tuberculosis and represents the archetype of the WXG100 family of proteins. Genes encoding ESAT-6 homologues have been identified in the genome of the human pathogen Streptococcus agalactiae; one of these genes, esxA, has been cloned and the recombinant protein has been crystallized. In contrast to M. tuberculosis ESAT-6, the crystal structure of GBS1074 reveals a homodimeric structure similar to homologous structures from Staphylococcus aureus and Helicobacter pylori. Intriguingly, GBS1074 forms elongated fibre-like assemblies in the crystal structure

  2. Structure of Streptococcus agalactiae tip pilin GBS104: a model for GBS pili assembly and host interactions

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    Krishnan, Vengadesan [UNESCO Regional Centre for Biotechnology (RCB), Gurgaon 122 016, Haryana (India); Dwivedi, Prabhat [University of Texas Health Science Center, Houston, TX 77030 (United States); Kim, Brandon J. [San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 (United States); Samal, Alexandra; Macon, Kevin [University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Ma, Xin; Mishra, Arunima [University of Texas Health Science Center, Houston, TX 77030 (United States); Doran, Kelly S. [San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 (United States); Ton-That, Hung [University of Texas Health Science Center, Houston, TX 77030 (United States); Narayana, Sthanam V. L., E-mail: narayana@uab.edu [University of Alabama at Birmingham, Birmingham, AL 35294 (United States); UNESCO Regional Centre for Biotechnology (RCB), Gurgaon 122 016, Haryana (India)

    2013-06-01

    The crystal structure of a 75 kDa central fragment of GBS104, a tip pilin from the 2063V/R strain of Streptococcus agalactiae (group B streptococcus; GBS), is reported. The crystal structure of a 75 kDa central fragment of GBS104, a tip pilin from the 2063V/R strain of Streptococcus agalactiae (group B streptococcus; GBS), is reported. In addition, a homology model of the remaining two domains of GBS104 was built and a model of full-length GBS104 was generated by combining the homology model (the N1 and N4 domains) and the crystal structure of the 75 kDa fragment (the N2 and N3 domains). This rod-shaped GBS104 model is constructed of three IgG-like domains (the N1, N2 and N4 domains) and one vWFA-like domain (the N3 domain). The N1 and N2 domains of GBS104 are assembled with distinct and remote segments contributed by the N- and C-termini. The metal-binding site in the N3 domain of GBS104 is in the closed/low-affinity conformation. Interestingly, this domain hosts two long arms that project away from the metal-binding site. Using site-directed mutagenesis, two cysteine residues that lock the N3 domain of GBS104 into the open/high-affinity conformation were introduced. Both wild-type and disulfide-locked recombinant proteins were tested for binding to extracellular matrix proteins such as collagen, fibronectin, fibrinogen and laminin, and an increase in fibronectin binding affinity was identified for the disulfide-locked N3 domain, suggesting that induced conformational changes may play a possible role in receptor binding.

  3. Structure of Streptococcus agalactiae tip pilin GBS104: a model for GBS pili assembly and host interactions

    International Nuclear Information System (INIS)

    Krishnan, Vengadesan; Dwivedi, Prabhat; Kim, Brandon J.; Samal, Alexandra; Macon, Kevin; Ma, Xin; Mishra, Arunima; Doran, Kelly S.; Ton-That, Hung; Narayana, Sthanam V. L.

    2013-01-01

    The crystal structure of a 75 kDa central fragment of GBS104, a tip pilin from the 2063V/R strain of Streptococcus agalactiae (group B streptococcus; GBS), is reported. The crystal structure of a 75 kDa central fragment of GBS104, a tip pilin from the 2063V/R strain of Streptococcus agalactiae (group B streptococcus; GBS), is reported. In addition, a homology model of the remaining two domains of GBS104 was built and a model of full-length GBS104 was generated by combining the homology model (the N1 and N4 domains) and the crystal structure of the 75 kDa fragment (the N2 and N3 domains). This rod-shaped GBS104 model is constructed of three IgG-like domains (the N1, N2 and N4 domains) and one vWFA-like domain (the N3 domain). The N1 and N2 domains of GBS104 are assembled with distinct and remote segments contributed by the N- and C-termini. The metal-binding site in the N3 domain of GBS104 is in the closed/low-affinity conformation. Interestingly, this domain hosts two long arms that project away from the metal-binding site. Using site-directed mutagenesis, two cysteine residues that lock the N3 domain of GBS104 into the open/high-affinity conformation were introduced. Both wild-type and disulfide-locked recombinant proteins were tested for binding to extracellular matrix proteins such as collagen, fibronectin, fibrinogen and laminin, and an increase in fibronectin binding affinity was identified for the disulfide-locked N3 domain, suggesting that induced conformational changes may play a possible role in receptor binding

  4. Streptococcus iniae and Streptococcus agalactiae

    Science.gov (United States)

    Streptococcus iniae and S. agalactiae are economically important Gram positive bacterial pathogens of cultured and wild fish with a worldwide distribution. Both bacteria are potential zoonotic pathogens and have been associated most often with infections in immunocompromised people. Streptococcus in...

  5. Genetic analysis of Streptococcus agalactiae strains isolated from neonates and their mothers.

    NARCIS (Netherlands)

    Melchers, W.J.G.; Bakkers, J.M.J.E.; Toonen, M.; Kuppeveld, F.J.M. van; Trijbels-Smeulders, M.J.A.M.; Hoogkamp-Korstanje, J.A.A.

    2003-01-01

    Streptococcus agalactiae or group B streptococcus (GBS) is the most common cause of neonatal sepsis and meningitis in neonates. One of the major questions is whether the GBS strains able to cause neonatal invasive disease have peculiar genetic features. A collection of S. agalactiae strains,

  6. Streptococcus agalactiae infection in Nile tilapia (Oreochromis niloticus) and its transmission potential to cohabitated sheepshead minnows (Cyprinodon variegatus)

    Science.gov (United States)

    Streptococcus agalactiae has emerged as an economically important bacterial pathogen affecting global aquaculture. Worldwide aquaculture losses due to S. agalactiae are estimated around U.S. $1 billion, annually. Streptococcus agalactiae also known as a Lancefield Group B Streptococcus (GBS) is a Gr...

  7. Natural outbreak of Streptococcus agalactiae (GBS) infection in wild giant Queensland grouper, Epinephelus lanceolatus (Bloch), and other wild fish in northern Queensland, Australia.

    Science.gov (United States)

    Bowater, R O; Forbes-Faulkner, J; Anderson, I G; Condon, K; Robinson, B; Kong, F; Gilbert, G L; Reynolds, A; Hyland, S; McPherson, G; Brien, J O'; Blyde, D

    2012-03-01

    Ninety-three giant Queensland grouper, Epinephelus lanceolatus (Bloch), were found dead in Queensland, Australia, from 2007 to 2011. Most dead fish occurred in northern Queensland, with a peak of mortalities in Cairns in June 2008. In 2009, sick wild fish including giant sea catfish, Arius thalassinus (Rüppell), and javelin grunter, Pomadasys kaakan (Cuvier), also occurred in Cairns. In 2009 and 2010, two disease epizootics involving wild stingrays occurred at Sea World marine aquarium. Necropsy, histopathology, bacteriology and PCR determined that the cause of deaths of 12 giant Queensland grouper, three wild fish, six estuary rays, Dasyatis fluviorum (Ogilby), one mangrove whipray, Himantura granulata (Macleay), and one eastern shovelnose ray, Aptychotrema rostrata (Shaw), was Streptococcus agalactiae septicaemia. Biochemical testing of 34 S. agalactiae isolates from giant Queensland grouper, wild fish and stingrays showed all had identical biochemical profiles. The 16S rRNA gene sequences of isolates confirmed all isolates were S. agalactiae; genotyping of selected S. agalactiae isolates showed the isolates from giant Queensland grouper were serotype Ib, whereas isolates from wild fish and stingrays closely resembled serotype II. This is the first report of S. agalactiae from wild giant Queensland grouper and other wild tropical fish and stingray species in Queensland, Australia. © 2012 Blackwell Publishing Ltd and State of Queensland.

  8. Serine-Rich Repeat Proteins and Pili Promote Streptococcus agalactiae Colonization of the Vaginal Tract

    NARCIS (Netherlands)

    Sheen, Tamsin R.; Jimenez, Alyssa; Wang, Nai-Yu; Banerjee, Anirban; van Sorge, Nina M.; Doran, Kelly S.

    2011-01-01

    Streptococcus agalactiae (group B streptococcus [GBS]) is a Gram-positive bacterium found in the female rectovaginal tract and is capable of producing severe disease in susceptible hosts, including newborns and pregnant women. The vaginal tract is considered a major reservoir for GBS, and maternal

  9. Streptococcus agalactiae infection in domestic rabbits, Oryctolagus cuniculus.

    Science.gov (United States)

    Ren, S Y; Geng, Y; Wang, K Y; Zhou, Z Y; Liu, X X; He, M; Peng, X; Wu, C Y; Lai, W M

    2014-12-01

    Streptococcus agalactiae (Group B streptococcus, GBS) has emerged as an important pathogen that affects humans and animals, including aquatic species. In August 2011, a severe infectious disease affecting rabbits, which caused 42% mortality, occurred in Mianyang, Sichuan Province, China. The main clinical signs included acute respiratory distress syndrome, fever, paddling and convulsions. A Gram-positive, chain-forming coccus was isolated from the primary organs and tissues of diseased rabbits and then identified as S. agalactiae by morphology, biochemical and physiological characteristics, 16S rDNA and gyrB gene sequences analysis. All isolates of S. agalactiae showed a similar antibiotic susceptibility, which were sensitive to florfenicol, ampicillin,gentamicin and norfloxacin, as well as being resistant to penicillin, amoxicillin and tetracycline. To our knowledge, this is the first report on S. agalactiae natural infection in domestic rabbits. © 2013 Blackwell Verlag GmbH.

  10. Streptococcus agalactiae: a vaginal pathogen?

    Science.gov (United States)

    Maniatis, A N; Palermos, J; Kantzanou, M; Maniatis, N A; Christodoulou, C; Legakis, N J

    1996-03-01

    The significance of Streptococcus agalactiae as an aetiological agent in vaginitis was evaluated. A total of 6226 samples from women who presented with vaginal symptoms was examined. The presence of >10 leucocytes/high-power field (h.p.f.) was taken to be the criterion of active infection. S. agalactiae was isolated from 10.1% of these samples. The isolation rates of other common pathogens such as Candida spp., Gardnerella vaginalis and Trichomonas spp. were 54.1%, 27.2% and 4.2%, respectively, in the same group of patients. In contrast, the isolation rates of these micro-organisms in the group of patients who had no infection (S. agalactiae was isolated, it was the sole pathogen isolated (83%) and its presence was associated with an inflammatory response in 80% of patients. Furthermore, the relative risk of vaginal infection with S. agalactiae (2.38) in patients with purulent vaginal discharge was greater than that of Candida spp. infection (1.41) and lower than that of Trichomonas spp. infection (8.32). These data suggest that S. agalactiae in symptomatic women with microscopic evidence of inflammation should be considered a causative agent of vaginitis.

  11. Antibiotic Susceptibilities and Serotyping of Clinical Streptococcus Agalactiae Isolates

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    Altay Atalay

    2011-11-01

    Full Text Available Objective: Streptococcus agalactiae (Group B streptococci, GBS are frequently responsible for sepsis and meningitis seen in the early weeks of life. GBS may cause perinatal infection and premature birth in pregnant women. The aim of this study was to serotype GBS strains isolated from clinical samples and evaluate their serotype distribution according to their susceptibilities to antibiotics and isolation sites. Material and Methods: One hundred thirty one S. agalactiae strains isolated from the clinical samples were included in the study. Of the strains, 99 were isolated from urine, 20 from soft tissue, 10 from blood and 2 from vaginal swab. Penicillin G and ceftriaxone susceptibilities of GBS were determined by the agar dilution method. Susceptibilities to erythromycin, clindamycin, vancomycin and tetracycline were determined by the Kirby-Bauer method according to CLSI criteria. Serotyping was performed using the latex aglutination method using specific antisera (Ia, Ib, II-VIII. Results: While in 131 GBS strains, serotypes VII and VIII were not detected, the most frequently isolated serotypes were types Ia (36%, III (30.5% and II (13% respectively. Serotype Ia was the most frequently seen serotype in all samples. All GBS isolates were susceptible to penicilin G, ceftriaxone and vancomycin. Among the strains, tetracycline, erythromycin and clindamycin resistance rates were determined as 90%, 14.5%, and 13% respectively. Conclusion: Penicillin is still the first choice of treatment for the infections with all serotypes of S. agalactiae in Turkey.

  12. Streptococcus agalactiae vaginitis: nonhemolytic variant on the Liofilchem® Chromatic StreptoB

    OpenAIRE

    Savini, Vincenzo; Marrollo, Roberta; D’Antonio, Marianna; D’Amario, Claudio; Fazii, Paolo; D’Antonio, Domenico

    2013-01-01

    Streptococcus agalactiae (group B Streptococcus, GBS) vaginal pathogenicity is not uniformly acknowledged throughout the literature; accordingly, in women, genital itching and burning, along with leukorrhea are commonly and almost exclusively referred to bacterial vaginosis, candidiasis and trichomoniasis. Conversely, GBS virulence for vagina was recognized in the past, as the organism has been observed to potentially cause local inflammation and discharge, as well as lactobacilli rarefaction...

  13. Human Streptococcus agalactiae strains in aquatic mammals and fish

    Science.gov (United States)

    2013-01-01

    Background In humans, Streptococcus agalactiae or group B streptococcus (GBS) is a frequent coloniser of the rectovaginal tract, a major cause of neonatal infectious disease and an emerging cause of disease in non-pregnant adults. In addition, Streptococcus agalactiae causes invasive disease in fish, compromising food security and posing a zoonotic hazard. We studied the molecular epidemiology of S. agalactiae in fish and other aquatic species to assess potential for pathogen transmission between aquatic species and humans. Methods Isolates from fish (n = 26), seals (n = 6), a dolphin and a frog were characterized by pulsed-field gel electrophoresis, multilocus sequence typing and standardized 3-set genotyping, i.e. molecular serotyping and profiling of surface protein genes and mobile genetic elements. Results Four subpopulations of S. agalactiae were identified among aquatic isolates. Sequence type (ST) 283 serotype III-4 and its novel single locus variant ST491 were detected in fish from Southeast Asia and shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. The human pathogenic strain ST7 serotype Ia was also detected in fish from Asia. ST23 serotype Ia, a subpopulation that is normally associated with human carriage, was found in all grey seals, suggesting that human effluent may contribute to microbial pollution of surface water and exposure of sea mammals to human pathogens. The final subpopulation consisted of non-haemolytic ST260 and ST261 serotype Ib isolates, which belong to a fish-associated clonal complex that has never been reported from humans. Conclusions The apparent association of the four subpopulations of S. agalactiae with specific groups of host species suggests that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. Furthermore, it provides a rational framework for exploration of pathogenesis and host-associated genome content of S

  14. Streptococcus agalactiae vaginitis: nonhemolytic variant on the Liofilchem® Chromatic StreptoB.

    Science.gov (United States)

    Savini, Vincenzo; Marrollo, Roberta; D'Antonio, Marianna; D'Amario, Claudio; Fazii, Paolo; D'Antonio, Domenico

    2013-01-01

    Streptococcus agalactiae (group B Streptococcus, GBS) vaginal pathogenicity is not uniformly acknowledged throughout the literature; accordingly, in women, genital itching and burning, along with leukorrhea are commonly and almost exclusively referred to bacterial vaginosis, candidiasis and trichomoniasis. Conversely, GBS virulence for vagina was recognized in the past, as the organism has been observed to potentially cause local inflammation and discharge, as well as lactobacilli rarefaction. We depict here a case where a nonhemolytic (γ-hemolytic) GBS strain was found to be the etiologic agent of vaginal infection. Such uncommon S. agalactiae phenotypes are hard to be recognized and may be therefore responsible for misdiagnosing and underestimation of GBS vaginitis prevalence; here, we had the support of the Liofilchem(®) Chromatic StreptoB medium, that successfully detected such an atypical variant.

  15. Identification of Streptococcus agalactiae by fluorescent in situ hybridization compared to culturing and the determination of prevalence of Streptococcus agalactiae colonization among pregnant women in Bushehr, Iran.

    Science.gov (United States)

    Tajbakhsh, Saeed; Norouzi Esfahani, Marjan; Emaneini, Mohammad; Motamed, Niloofar; Rahmani, Elham; Gharibi, Somayyeh

    2013-09-08

    Pregnant women colonized by Streptococcus agalactiae (group B streptococci [GBS]) may transfer this microorganism to their newborns. S. agalactiae is an important cause of pneumonia, sepsis, and meningitis in newborns. Fluorescent in situ hybridization (FISH) is considered as a method of identification in the field of diagnostic microbiology. In this paper, we have designed a study to compare the DNA FISH after 7 h Lim broth enrichment and culturing for the identification of S. agalactiae and to determine the prevalence of vaginal colonization by S. agalactiae among pregnant women in Bushehr, Iran. Vaginal swab specimens were obtained from 285 pregnant women at 35 weeks or more than 35 weeks of gestation. The specimens were inoculated into Lim broth. In order to evaluate the sensitivity and specificity of GBS DNA FISH after 7 h Lim broth enrichment, the specimens were tested using both FISH and conventional culture methods. In addition, the prevalence of GBS colonization was determined. Based on the results of this study, both the sensitivity and specificity of FISH were 100%. S. agalactiae was detected by both culture and FISH in 27 of the 285 pregnant women. Thus, the prevalence of GBS colonization was 9.5%. Since short-term (7 h) Lim broth enrichment followed by FISH using oligonucleotide probes showed a high sensitivity and specificity, this protocol is therefore a highly accurate and relatively rapid method for the detection of S. agalactiae. Our analysis suggests that the use of DNA FISH to screen for S. agalactiae colonization in pregnant women may be considered in the absence of GBS culture availability.

  16. Development of Streptococcus agalactiae vaccines for tilapia.

    Science.gov (United States)

    Liu, Guangjin; Zhu, Jielian; Chen, Kangming; Gao, Tingting; Yao, Huochun; Liu, Yongjie; Zhang, Wei; Lu, Chengping

    2016-12-21

    Vaccination is a widely accepted and effective method to prevent most pathogenic diseases in aquaculture. Various species of tilapia, especially Nile tilapia Oreochromis niloticus, are farmed worldwide because of their high consumer demand. Recently, the tilapia-breeding industry has been hampered by outbreaks of Streptococcus agalactiae infection, which cause high mortality and huge economic losses. Many researchers have attempted to develop effective S. agalactiae vaccines for tilapia. This review provides a summary of the different kinds of S. agalactiae vaccines for tilapia that have been developed recently. Among the various vaccine types, inactivated S. agalactiae vaccines showed superior protection efficiency when compared with live attenuated, recombinant and DNA vaccines. With respect to vaccination method, injecting the vaccine into tilapia provided the most effective immunoprotection. Freund's incomplete adjuvant appeared to be suitable for tilapia vaccines. Other factors, such as immunization duration and number, fish size and challenge dose, also influenced the vaccine efficacy.

  17. Capsule impairs efficient adherence of Streptococcus agalactiae to intestinal epithelium in tilapias Oreochromis sp.

    Science.gov (United States)

    Barato, P; Martins, E R; Vasquez, G M; Ramirez, M; Melo-Cristino, J; Martínez, N; Iregui, C

    2016-11-01

    Streptococcosis caused by Streptococcus agalactiae is one of the most important diseases in the tilapia aquaculture industry. The role of the capsule of Streptococcus agalactiae in adherence to fish surfaces has not been evaluated and the mechanism of capsular regulation during adhesion has not been described. The aim of this study was to evaluate the role of the capsule of S. agalactiae during adhesion to intestinal epithelium of tilapia (Oreochromis sp.) in an ex vivo infection model. We show that the capsule impairs the adhesion of bacteria to host intestinal epithelium. Wild type (WT) strain SaTiBe08-18 (S. agalactiae recovered from tilapia) had reduced adhesion (P S. agalactiae to tilapia intestine and that the acidic milieu could regulate adherence of encapsulated strains. We found GlcNAc on the surface of adherent Δcps but not over the capsule in WT. This difference could be explained by the GlcNAc composition of Lancefield group B antigen and the peptidoglycan in GBS (Group B Streptococcus) and also may be related with better exposure of glycosylated adhesins in unencapsulated fish GBS. Understanding capsular regulation during adhesion of S. agalactiae may provide new leads to find a successful anti-adherence therapy to prevent streptococcosis in tilapia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Molecular Characterization of Streptococcus agalactiae Isolates From Pregnant and Non-Pregnant Women at Yazd University Hospital, Iran

    OpenAIRE

    Sadeh, Maryam; Firouzi, Roya; Derakhshandeh, Abdollah; Bagher Khalili, Mohammad; Kong, Fanrong; Kudinha, Timothy

    2016-01-01

    Background: Streptococcus agalactiae (Group B streptococcus, GBS) that colonize the vaginas of pregnant women may occasionally cause neonatal infections. It is one of the most common causes of sepsis and meningitis in neonates and of invasive diseases in pregnant women. It can also cause infectious disease among immunocompromised individuals. The distribution of capsular serotypes and genotypes varies over time and by geographic era. The serotyping and genotyping data of GBS in Iranian pregna...

  19. Structural characterization of the virulence factor nuclease A from Streptococcus agalactiae.

    Science.gov (United States)

    Moon, Andrea F; Gaudu, Philippe; Pedersen, Lars C

    2014-11-01

    The group B pathogen Streptococcus agalactiae commonly populates the human gut and urogenital tract, and is a major cause of infection-based mortality in neonatal infants and in elderly or immunocompromised adults. Nuclease A (GBS_NucA), a secreted DNA/RNA nuclease, serves as a virulence factor for S. agalactiae, facilitating bacterial evasion of the human innate immune response. GBS_NucA efficiently degrades the DNA matrix component of neutrophil extracellular traps (NETs), which attempt to kill and clear invading bacteria during the early stages of infection. In order to better understand the mechanisms of DNA substrate binding and catalysis of GBS_NucA, the high-resolution structure of a catalytically inactive mutant (H148G) was solved by X-ray crystallography. Several mutants on the surface of GBS_NucA which might influence DNA substrate binding and catalysis were generated and evaluated using an imidazole chemical rescue technique. While several of these mutants severely inhibited nuclease activity, two mutants (K146R and Q183A) exhibited significantly increased activity. These structural and biochemical studies have greatly increased our understanding of the mechanism of action of GBS_NucA in bacterial virulence and may serve as a foundation for the structure-based drug design of antibacterial compounds targeted to S. agalactiae.

  20. Incidence and serotype characterisation of Streptococcus agalactiae in a Portuguese hospital.

    Science.gov (United States)

    Pinto, Ana Mafalda; Pereira, Tamegão Aires; Alves, Valquíria; Araújo, António; Lage, Olga Maria

    2018-06-01

    Streptococcus agalactiae, commonly known as group B Streptococcus (GBS), has been recognised as a worldwide causative pathogenic agent of neonatal sepsis, meningitis and pneumonia. To better understand the behaviour of S. agalactiae in pregnant women from a hospital from the North of Portugal, retrospective analyses were performed to describe epidemiological, clinical and microbiological characteristics of the isolates obtained. Based on laboratorial records and the hospital's patient files, a 6-year retrospective study was performed to analyse S. agalactiae isolates from screened pregnant women between 35 and 37 weeks of gestation and hospitalised neonates from pregnant women between 24 and 41 weeks of gestation admitted in Hospital Pedro Hispano. Serotype characterisation was also performed in 67 GBS strains. In 6692 pregnant women between 35 and 37 weeks of gestation screened between 2011 and 2016, a total of 1377 S. agalactiae isolates (21%) were found. A high percentage (40%) of unknown colonisation status among hospitalised neonates from pregnant women between 24 and 41 weeks of gestations was also found. The incidence of neonatal sepsis was 8.7 (95% CI 7.0 to 10.8) cases per 1000 live births. Regarding serotype characterisation, serotype III (22.4%) was the most frequent, followed by serotype Ia (19.4%) and serotypes Ib and V (both with 17.9%). High epidemiological values of GBS colonisation and incidence were found in this study. In Portugal studies on the epidemiology and behaviour of S. agalactiae remain limited, reinforcing the importance and need for S. agalactiae screening across the country. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  1. Identification of immunoreactive proteins of Streptococcus agalactiae isolated from cultured tilapia in China.

    Science.gov (United States)

    Liu, Guangjin; Zhang, Wei; Lu, Chengping

    2013-12-01

    Streptococcus agalactiae (Group B streptococcus, GBS) is an important zoonotic pathogen that can cause lethal infections in humans and animals, including aquatic species. Immunoreactive proteins of the S. agalactiae strain, GD201008-001, isolated from cultured tilapia in China, were screened by immunoproteomics using hyperimmune sera, convalescent guinea pig sera and GD201008-001-infected tilapia antisera as primary detection antibodies. A total of 16 different proteins were identified including 13 novel immunoreactive proteins of S. agalactiae. Four proteins, serine-rich repeat glycoprotein 1, branched-chain alpha-keto acid dehydrogenase (BKD) subunit E2, 5'-nucleotidase family protein and ornithine carbamoyltransferase, were shown to react with the three types of sera and thus were considered to represent novel S. agalactiae vaccine candidate antigens. Our findings represent the basis for vaccine development for piscine S. agalactiae and are necessary for understanding virulence factors and immunogenicity of S. agalactiae with different hosts. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  2. Comparative genomics and the role of lateral gene transfer in the evolution of bovine adapted Streptococcus agalactiae

    Science.gov (United States)

    Richards, Vincent P.; Lang, Ping; Pavinski Bitar, Paulina D.; Lefébure, Tristan; Schukken, Ynte H.; Zadoks, Ruth N.; Stanhope, Michael J.

    2011-01-01

    In addition to causing severe invasive infections in humans, Streptococcus agalactiae, or group B Streptococcus (GBS), is also a major cause of bovine mastitis. Here we provide the first genome sequence for S. agalactiae isolated from a cow diagnosed with clinical mastitis (strain FSL S3-026). Comparison to eight S. agalactiae genomes obtained from human disease isolates revealed 183 genes specific to the bovine strain. Subsequent polymerase chain reaction (PCR) screening for the presence/absence of a subset of these loci in additional bovine and human strains revealed strong differentiation between the two groups (Fisher exact test: p S. agalactiae with Streptococcus uberis (nisin U operon) and Streptococcus dysgalactiae subsp. dysgalactiae (lactose operon). We also found evidence for LGT, involving the salivaricin operon, between the bovine S. agalactiae strain and either Streptococcus pyogenes or Streptococcus salivarius. Our findings provide insight intomechanismsfacilitatingenvironmentaladaptationandacquisitionofpotential virulence factors, while highlighting both the key role LGT has played in the recent evolution of the bovine S. agalactiae strain, and the importance of LGT among pathogens within a shared environment. PMID:21536150

  3. Interaction of Streptococcus agalactiae and cellular innate immunity in colonization and disease

    Directory of Open Access Journals (Sweden)

    Sybille eLandwehr-Kenzel

    2014-10-01

    Full Text Available Streptococcus agalactiae (Group B streptococcus, GBS is highly adapted to humans, where it is a normal constituent of the intestinal and vaginal flora. Yet, GBS has highly invasive potential and causes excessive inflammation, sepsis and death at the beginning of life, in the elderly and in diabetic patients. Thus GBS is a model pathobiont that thrives in the healthy host, but has not lost its potential virulence during coevolution with mankind. It remains incompletely understood how the innate immune system contains GBS in the natural niches, the intestinal and genital tracts, and which molecular events underlie breakdown of mucocutaneous resistance. Newborn infants between days seven and 90 of life are at risk of a particularly striking sepsis manifestation (late onset disease, LOD, where the transition from colonization to invasion and dissemination, and thus from health to severe sepsis is typically fulminant and not predictable. The great majority of late-onset sepsis cases is caused by one clone, GBS ST-17, which expresses HvgA as a signature virulence factor and adhesin. In mice, HvgA promotes the crossing of both the mucosal and the blood brain barrier. Expression levels of HvgA and other GBS virulence factors, such as pili and toxins, are regulated by the upstream two-component control system CovR/S. This in turn is modulated by acidic epithelial pH, high glucose levels and during the passage through the mouse intestine. After invasion, GBS has the ability to subvert innate immunity by mechanisms like GAPDH-dependent induction of IL-10 and β-protein binding to the inhibitory phagocyte receptors sialic acid binding immunoglobulin-like lectin 5 and 14. On the host side, sensing of GBS nucleic acids and lipopeptides by both Toll-like receptors (TLRs and the inflammasome appears to be critical for host resistance against GBS. Yet, comprehensive models on the interplay between GBS and human immune cells at the colonizing site are just

  4. Molecular Methods for Typing of Streptococcus agalactiae with Special Emphasis on the Development and Validation of a Multi-Locus Variable Number of Tandem Repeats Assay (MLVA)

    OpenAIRE

    Radtke, Andreas

    2012-01-01

    Molekylære metoder for typing av Streptococcus agalactiae med særlig vektlegging av utvikling og validering av et multi-locus variable number of tandem repeats assay (MLVA) Sammendraget: Streptococcus agalactiae eller gruppe B streptokokker (GBS) forårsaker livsfarlige infeksjoner hos nyfødte, gravide eller voksne med kroniske sykdommer. Den forårsaker også jurbetennelse i storfe. Typing av GBS gir innblikk i bakteriens epidemiologi og dens fylogenetiske slektskap. Ulike deler av bakterie...

  5. Survey of immunological features of the alpha-like proteins of Streptococcus agalactiae.

    Science.gov (United States)

    Maeland, Johan A; Afset, Jan E; Lyng, Randi V; Radtke, Andreas

    2015-02-01

    Nearly all Streptococcus agalactiae (group B streptococcus [GBS]) strains express a protein which belongs to the so-called alpha-like proteins (Alps), of which Cα, Alp1, Alp2, Alp3, Rib, and Alp4 are known to occur in GBS. The Alps are chimeras which form mosaic structures on the GBS surface. Both N- and C-terminal stretches of the Alps possess immunogenic sites of dissimilar immunological specificity. In this review, we have compiled data dealing with the specificity of the N- and C-terminal immunogenic sites of the Alps. The majority of N-terminal sites show protein specificity while the C-terminal sites show broader cross-reactivity. Molecular serotyping has revealed that antibody-based serotyping has often resulted in erroneous Alp identification, due to persistence of cross-reacting antibodies in antisera for serotyping. Retrospectively, this could be expected on the basis of sequence analysis results. Some of the historical R proteins are in fact Alps. The data included in the review may provide a basis for decisions regarding techniques for the preparation of specific antisera for serotyping of GBS, for use in other approaches in GBS research, and for decision making in the context of GBS vaccine developments. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Molecular Characterization of Streptococcus agalactiae Causing Community- and Hospital-acquired Infections in Shanghai, China

    Directory of Open Access Journals (Sweden)

    Haoqin Jiang

    2016-08-01

    Full Text Available Streptococcus agalactiae, a colonizing agent in pregnant women and the main cause of neonatal sepsis and meningitis, has been increasingly associated with invasive disease in nonpregnant adults. We collected a total of 87 non-repetitive S. agalactiae isolates causing community-acquired (CA and hospital-acquired (HA infections in nonpregnant adults from a teaching hospital in Shanghai between 2009 and 2013. We identified and characterized their antibiotic resistance, sequence type (ST, serotype, virulence, and biofilm formation. The most frequent STs were ST19 (29.9%, ST23 (16.1%, ST12 (13.8%, and ST1 (12.6%. ST19 had significantly different distributions between CA- and HA-group B Streptococci (GBS isolates. The most frequent serotypes were III (32.2%, Ia (26.4%, V (14.9%, Ib (13.8%, and II (5.7%. Serotype III/ST19 was significantly associated with levofloxacin resistance in all isoates. The HA-GBS multidrug resistant rate was much higher than that of CA-GBS. Virulence genes pavA, cfb were found in all isolates. Strong correlations exist between serotype Ib (CA and HA and surface protein genes spb1 and bac, serotype III (HA and surface protein gene cps and GBS pilus cluster. The serotype, epidemic clone, PFGE-based genotype, and virulence gene are closely related between CA-GBS and HA-GBS, and certain serotypes and clone types were significantly associated with antibiotic resistance. However, CA-GBS and HA-GBS still had significant differences in their distribution of clone types, antibiotic resistance, and specific virulence genes, which may provide a basis for infection control.

  7. Effect of Eugenol against Streptococcus agalactiae and Synergistic Interaction with Biologically Produced Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Renata Perugini Biasi-Garbin

    2015-01-01

    Full Text Available Streptococcus agalactiae (group B streptococci (GBS is an important infections agent in newborns associated with maternal vaginal colonization. Intrapartum antibiotic prophylaxis in GBS-colonized pregnant women has led to a significant reduction in the incidence of early neonatal infection in various geographic regions. However, this strategy may lead to resistance selecting among GBS, indicating the need for new alternatives to prevent bacterial transmission and even to treat GBS infections. This study reported for the first time the effect of eugenol on GBS isolated from colonized women, alone and in combination with silver nanoparticles produced by Fusarium oxysporum (AgNPbio. Eugenol showed a bactericidal effect against planktonic cells of all GBS strains, and this effect appeared to be time-dependent as judged by the time-kill curves and viability analysis. Combination of eugenol with AgNPbio resulted in a strong synergistic activity, significantly reducing the minimum inhibitory concentration values of both compounds. Scanning and transmission electron microscopy revealed fragmented cells and changes in bacterial morphology after incubation with eugenol. In addition, eugenol inhibited the viability of sessile cells during biofilm formation and in mature biofilms. These results indicate the potential of eugenol as an alternative for controlling GBS infections.

  8. Serine-rich repeat proteins and pili promote Streptococcus agalactiae colonization of the vaginal tract.

    Science.gov (United States)

    Sheen, Tamsin R; Jimenez, Alyssa; Wang, Nai-Yu; Banerjee, Anirban; van Sorge, Nina M; Doran, Kelly S

    2011-12-01

    Streptococcus agalactiae (group B streptococcus [GBS]) is a Gram-positive bacterium found in the female rectovaginal tract and is capable of producing severe disease in susceptible hosts, including newborns and pregnant women. The vaginal tract is considered a major reservoir for GBS, and maternal vaginal colonization poses a significant risk to the newborn; however, little is known about the specific bacterial factors that promote GBS colonization and persistence in the female reproductive tract. We have developed in vitro models of GBS interaction with the human female cervicovaginal tract using human vaginal and cervical epithelial cell lines. Analysis of isogenic mutant GBS strains deficient in cell surface organelles such as pili and serine-rich repeat (Srr) proteins shows that these factors contribute to host cell attachment. As Srr proteins are heavily glycosylated, we confirmed that carbohydrate moieties contribute to the effective interaction of Srr-1 with vaginal epithelial cells. Antibody inhibition assays identified keratin 4 as a possible host receptor for Srr-1. Our findings were further substantiated in an in vivo mouse model of GBS vaginal colonization, where mice inoculated with an Srr-1-deficient mutant exhibited decreased GBS vaginal persistence compared to those inoculated with the wild-type (WT) parental strain. Furthermore, competition experiments in mice showed that WT GBS exhibited a significant survival advantage over the ΔpilA or Δsrr-1 mutant in the vaginal tract. Our results suggest that these GBS surface proteins contribute to vaginal colonization and may offer new insights into the mechanisms of vaginal niche establishment.

  9. Serine-Rich Repeat Proteins and Pili Promote Streptococcus agalactiae Colonization of the Vaginal Tract ▿

    Science.gov (United States)

    Sheen, Tamsin R.; Jimenez, Alyssa; Wang, Nai-Yu; Banerjee, Anirban; van Sorge, Nina M.; Doran, Kelly S.

    2011-01-01

    Streptococcus agalactiae (group B streptococcus [GBS]) is a Gram-positive bacterium found in the female rectovaginal tract and is capable of producing severe disease in susceptible hosts, including newborns and pregnant women. The vaginal tract is considered a major reservoir for GBS, and maternal vaginal colonization poses a significant risk to the newborn; however, little is known about the specific bacterial factors that promote GBS colonization and persistence in the female reproductive tract. We have developed in vitro models of GBS interaction with the human female cervicovaginal tract using human vaginal and cervical epithelial cell lines. Analysis of isogenic mutant GBS strains deficient in cell surface organelles such as pili and serine-rich repeat (Srr) proteins shows that these factors contribute to host cell attachment. As Srr proteins are heavily glycosylated, we confirmed that carbohydrate moieties contribute to the effective interaction of Srr-1 with vaginal epithelial cells. Antibody inhibition assays identified keratin 4 as a possible host receptor for Srr-1. Our findings were further substantiated in an in vivo mouse model of GBS vaginal colonization, where mice inoculated with an Srr-1-deficient mutant exhibited decreased GBS vaginal persistence compared to those inoculated with the wild-type (WT) parental strain. Furthermore, competition experiments in mice showed that WT GBS exhibited a significant survival advantage over the ΔpilA or Δsrr-1 mutant in the vaginal tract. Our results suggest that these GBS surface proteins contribute to vaginal colonization and may offer new insights into the mechanisms of vaginal niche establishment. PMID:21984789

  10. Whole genome shotgun sequencing of Indian strains of Streptococcus agalactiae

    Directory of Open Access Journals (Sweden)

    Balaji Veeraraghavan

    2017-12-01

    Full Text Available Group B streptococcus is known as a leading cause of neonatal infections in developing countries. The present study describes the whole genome shotgun sequences of four Group B Streptococcus (GBS isolates. Molecular data on clonality is lacking for GBS in India. The present genome report will add important information on the scarce genome data of GBS and will help in deriving comparative genome studies of GBS isolates at global level. This Whole Genome Shotgun project has been deposited at DDBJ/ENA/GenBank under the accession numbers NHPL00000000 – NHPO00000000.

  11. Assignment of Streptococcus agalactiae isolates to clonal complexes using a small set of single nucleotide polymorphisms.

    Science.gov (United States)

    Honsa, Erin; Fricke, Thomas; Stephens, Alex J; Ko, Danny; Kong, Fanrong; Gilbert, Gwendolyn L; Huygens, Flavia; Giffard, Philip M

    2008-08-19

    Streptococcus agalactiae (Group B Streptococcus (GBS)) is an important human pathogen, particularly of newborns. Emerging evidence for a relationship between genotype and virulence has accentuated the need for efficient and well-defined typing methods. The objective of this study was to develop a single nucleotide polymorphism (SNP) based method for assigning GBS isolates to multilocus sequence typing (MLST)-defined clonal complexes. It was found that a SNP set derived from the MLST database on the basis of maximization of Simpsons Index of Diversity provided poor resolution and did not define groups concordant with the population structure as defined by eBURST analysis of the MLST database. This was interpreted as being a consequence of low diversity and high frequency horizontal gene transfer. Accordingly, a different approach to SNP identification was developed. This entailed use of the "Not-N" bioinformatic algorithm that identifies SNPs diagnostic for groups of known sequence variants, together with an empirical process of SNP testing. This yielded a four member SNP set that divides GBS into 10 groups that are concordant with the population structure. A fifth SNP was identified that increased the sensitivity for the clinically significant clonal complex 17 to 100%. Kinetic PCR methods for the interrogation of these SNPs were developed, and used to genotype 116 well characterized isolates. A five SNP method for dividing GBS into biologically valid groups has been developed. These SNPs are ideal for high throughput surveillance activities, and combining with more rapidly evolving loci when additional resolution is required.

  12. Molecular Characterization of Streptococcus agalactiae Isolated from Bovine Mastitis in Eastern China

    Science.gov (United States)

    Yang, Yongchun; Liu, Yinglong; Ding, Yunlei; Yi, Li; Ma, Zhe; Fan, Hongjie; Lu, Chengping

    2013-01-01

    One hundred and two Streptococcus agalactiae (group B streptococcus [GBS]) isolates were collected from dairy cattle with subclinical mastitis in Eastern China during 2011. Clonal groups were established by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE), respectively. Capsular polysaccharides (CPS), pilus and alpha-like-protein (Alp) family genes were also characterized by molecular techniques. MLST analysis revealed that these isolates were limited to three clonal groups and were clustered in six different lineages, i.e. ST (sequence type) 103, ST568, ST67, ST301, ST313 and ST570, of which ST568 and ST570 were new genotypes. PFGE analysis revealed this isolates were clustered in 27 PFGE types, of which, types 7, 8, 14, 15, 16, 18, 23 and 25 were the eight major types, comprising close to 70% (71/102) of all the isolates. The most prevalent sequence types were ST103 (58% isolates) and ST568 (31% isolates), comprising capsular genotype Ia isolates without any of the detected Alp genes, suggesting the appearance of novel genomic backgrounds of prevalent strains of bovine S. agalactiae. All the strains possessed the pilus island 2b (PI-2b) gene and the prevalent capsular genotypes were types Ia (89% isolates) and II (11% isolates), the conserved pilus type providing suitable data for the development of vaccines against mastitis caused by S. agalactiae. PMID:23874442

  13. Culture-Negative Neonatal Meningitis and Endocarditis Caused by Streptococcus agalactiae

    OpenAIRE

    Nègre, Valérie Lefranc; Colin-Gorski, Anne-Marie; Magnier, Suzel; Maisonneuve, Lydia; Aujard, Yannick; Bingen, Edouard; Bonacorsi, Stéphane

    2004-01-01

    We describe a case of culture-negative meningitis and endocarditis caused by Streptococcus agalactiae in a 27-day-old boy. S. agalactiae was detected in cerebrospinal fluid and serum by broad-spectrum PCR amplification.

  14. Endocytosis‒Mediated Invasion and Pathogenicity of Streptococcus agalactiae in Rat Cardiomyocyte (H9C2)

    OpenAIRE

    Pooja, Sharma; Pushpanathan, Muthuirulan; Gunasekaran, Paramasamy; Rajendhran, Jeyaprakash

    2015-01-01

    Streptococcus agalactiae infection causes high mortality in cardiovascular disease (CVD) patients, especially in case of setting prosthetic valve during cardiac surgery. However, the pathogenesis mechanism of S. agalactiae associate with CVD has not been well studied. Here, we have demonstrated the pathogenicity of S. agalactiae in rat cardiomyocytes (H9C2). Interestingly, both live and dead cells of S. agalactiae were uptaken by H9C2 cells. To further dissect the process of S. agalactiae int...

  15. [Isolation and characterization of siphovirus phages infecting bovine Streptococcus agalactiae].

    Science.gov (United States)

    Bai, Qinqin; Yang, Yongchun; Lu, Chengping

    2016-02-04

    To isolate and identify Streptococcus agalactiae phages and screen candidate phages to control infection caused by bovine S. agalactiae. We used two methods for isolation of S. agalactiae phages, namely (1) isolation of phages from milk and environmental samples, and (2) isolation of phages via induction of lysogens with Mitomycin C. Double-layer agar culture method was used to purify phages. Then the newly obtained phages, with S. agalactiae phage JX01 isolated from mastitis milk, were comparatively analyzed in the following aspects: morphology of phages by transmission electron microscopy, host range of phages to 55 S. agalactiae strains and other Streptococcus strains, phages DNA using EcoR I, Xba I, Pst I and Sal I, the optical multiplicity of infection, absorption curve and one step growth curve, and the stability of phages at different storage conditions. The comparative analysis of the 3 novel phages LYGO9, HZ04 and pA11 (induced from S. agalctiae bovine clinical isolate HAJL2011070601) with JX01 showed that the 4 phages were classified as the member of Siphovirdae family. EcoR I, Sal I, Xba I and Pst I separately digested the 4 phages DNA provided 4, 3, 3 and 2 profiles, respectively. This suggested that they were different strains. All the 4 phages specifically infected bovine S. agalactiae isolates. LYGO9, pA11, JX01 and HZ04 could lyse 12, 13, 20 and 23 of 42 tested bovine S. agalctiae isolates, respectively. This clearly indicated that these 4 phages are closely related. The 3 new phages which specifically lyse bovine S. agalactiae isolates are siphovirus phages. Phage LYGO9 was shown having a short latent period and a larger burst size.

  16. Emergence of respiratory Streptococcus agalactiae isolates in cystic fibrosis patients.

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    Vera Eickel

    Full Text Available Streptococcus agalactiae is a well-known pathogen for neonates and immunocompromized adults. Beyond the neonatal period, S. agalactiae is rarely found in the respiratory tract. During 2002-2008 we noticed S. agalactiae in respiratory secretions of 30/185 (16% of cystic fibrosis (CF patients. The median age of these patients was 3-6 years older than the median age CF patients not harboring S. agalactiae. To analyze, if the S. agalactiae isolates from CF patients were clonal, further characterization of the strains was achieved by capsular serotyping, surface protein determination and multilocus sequence typing (MLST. We found a variety of sequence types (ST among the isolates, which did not substantially differ from the MLST patterns of colonizing strains from Germany. However serotype III, which is often seen in colonizing strains and invasive infections was rare among CF patients. The emergence of S. agalactiae in the respiratory tract of CF patients may represent the adaptation to a novel host environment, supported by the altered surfactant composition in older CF patients.

  17. Antibacterial activity and mechanism of berberine against Streptococcus agalactiae.

    Science.gov (United States)

    Peng, Lianci; Kang, Shuai; Yin, Zhongqiong; Jia, Renyong; Song, Xu; Li, Li; Li, Zhengwen; Zou, Yuanfeng; Liang, Xiaoxia; Li, Lixia; He, Changliang; Ye, Gang; Yin, Lizi; Shi, Fei; Lv, Cheng; Jing, Bo

    2015-01-01

    The antibacterial activity and mechanism of berberine against Streptococcus agalactiae were investigated in this study by analyzing the growth, morphology and protein of the S. agalactiae cells treated with berberine. The antibacterial susceptibility test result indicated minimum inhibition concentration (MIC) of berberine against Streptococcus agalactiae was 78 μg/mL and the time-kill curves showed the correlation of concentration-time. After the bacteria was exposed to 78 μg/mL berberine, the fragmentary cell membrane and cells unequal division were observed by the transmission electron microscopy (TEM), indicating the bacterial cells were severely damaged. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) study demonstrated that berberine could damage bacterial cells through destroying cellular proteins. Meanwhile, Fluorescence microscope revealed that berberine could affect the synthesis of DNA. In conclusion, these results strongly suggested that berberine may damage the structure of bacterial cell membrane and inhibit synthesis of protein and DNA, which cause Streptococcus agalactiae bacteria to die eventually.

  18. Evaluation of the surveillance program of Streptococcus agalactiae in Danish dairy herds

    DEFF Research Database (Denmark)

    Andersen, H. J.; Pedersen, L. H.; Aarestrup, Frank Møller

    2003-01-01

    The aim of this study was to evaluate the Danish surveillance program of Streptococcus agalactiae in dairy herds with respect to 1) fluctuation over time of the presence of S. agalactiae in bulk tank milk, 2) sensitivity and specificity of the bacteriological method used, and 3) contamination...... the isolates. Streptococcus agalactiae was found in eight of 96 herds in which S. agalactiae had never previously been found during the surveillance program. Streptococcus agalactiae was not found in all seven sampling rounds in any of the eight herds. Comparing the approved method with supplemental findings...

  19. Remodeling of the Streptococcus agalactiae transcriptome in response to growth temperature.

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    Laurent Mereghetti

    Full Text Available BACKGROUND: To act as a commensal bacterium and a pathogen in humans and animals, Streptococcus agalactiae (group B streptococcus, GBS must be able to monitor and adapt to different environmental conditions. Temperature variation is a one of the most commonly encountered variables. METHODOLOGY/PRINCIPAL FINDINGS: To understand the extent to which GBS modify gene expression in response to temperatures encountered in the various hosts, we conducted a whole genome transcriptome analysis of organisms grown at 30 degrees C and 40 degrees C. We identified extensive transcriptome remodeling at various stages of growth, especially in the stationary phase (significant transcript changes occurred for 25% of the genes. A large proportion of genes involved in metabolism was up-regulated at 30 degrees C in stationary phase. Conversely, genes up-regulated at 40 degrees C relative to 30 degrees C include those encoding virulence factors such as hemolysins and extracellular secreted proteins with LPXTG motifs. Over-expression of hemolysins was linked to larger zones of hemolysis and enhanced hemolytic activity at 40 degrees C. A key theme identified by our study was that genes involved in purine metabolism and iron acquisition were significantly up-regulated at 40 degrees C. CONCLUSION/SIGNIFICANCE: Growth of GBS in vitro at different temperatures resulted in extensive remodeling of the transcriptome, including genes encoding proven and putative virulence genes. The data provide extensive new leads for molecular pathogenesis research.

  20. Streptococcus agalactiae: an emerging cause of septic arthritis.

    Science.gov (United States)

    Louthrenoo, Worawit; Kasitanon, Nuntana; Wangkaew, Suparaporn; Hongsongkiat, Sith; Sukitawut, Waraporn; Wichainun, Ramjai

    2014-03-01

    Invasive Streptococcus agalactiae infection in nonpregnant women has been reported increasingly worldwide. This study reports the clinical features and outcome of S. agalactiae septic arthritis in Thai patients. The medical records of cases with septic arthritis seen between July 1990 and December 2010 were reviewed. Only those with S. agalactiae were included in this study. From 244 cases of septic arthritis, 38 (15.57%, 13 men and 25 women) were caused by S. agalactiae, with 34 of them (89.48%) occurring between 2008 and 2010. Their mean age was 52.89 (SD, 18.95) years. Twenty-four of the 38 patients (63.16%) had 1 or more underlying disease that might predispose to joint infection. Fever and joint pain were the most common symptoms presented. Eleven cases (28.95%) presented monoarthritis, 15 (39.47%) oligoarthritis, and 12 (31.58%) polyarthritis, with a mean joint involvement of 3.34 (SD, 2.35) joints (range, 1-8). Cellulitis was seen in 27 cases (71.05%). Blood cultures were positive in 31 patients (81.58%). Thirty-five of the 38 synovial fluid specimens obtained were enough for cultures and stain smears, with 24 (68.57%) growing S. agalactiae and 19 (54.29%) showing gram-positive cocci. All isolates were sensitive to penicillin. Ten patients (26.31%) received arthroscopic drainage. The articular outcome was good in 11 patients, fair in 24, and poor in 3. There were no deaths. Streptococcus agalactiae is an emerging cause of septic arthritis in Thai patients. Physicians should be especially aware of this condition in patients presenting with acute oligopolyarthritis and prominent cellulitis.

  1. DETEKSI POLYMORPHISME DENGAN SUBSTITUSI NUKLEOTIDA TUNGGAL PADA Streptococcus agalactiae ISOLAT LOKAL INDONESIA

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    Angela Mariana Lusiastuti

    2015-12-01

    Full Text Available Kasus penyakit pada budidaya ikan nila di wilayah di Jawa Barat, Jawa Tengah, Jawa Timur, Sulawesi Utara dan Papua Barat, disebabkan Streptococcus yang menyebabkan penyakit Streptococcosis di mana 80% disebabkan oleh grup B S. agalactiae. Tujuan penelitian ini adalah melakukan deteksi pada nukleotida isolat S. agalactiae untuk mengetahui sampai sejauh mana terjadinya nukleotida polimorfisme tunggal (SNP pada isolat tersebut. Identifikasi menggunakan PCR dilakukan terhadap 16S rDNA dan primer spesifik spesies terhadap S. agalactiae yaitu agal I 5’-ATAAGAGTAATTAACACATGTTAG-3’ (forward dan agal II 5’-ACTTCGGGTGTTACAAAC-3’(reverse dengan target 1250 bp. Produk PCR diamplifikasi terlebih dahulu menggunakan tujuh pasangan primer oligonukleotida yang berbeda yang didesain dari sekuens genom NEM316 GBS. Sekuens yang diperoleh dibandingkan dengan sekuens di Gene Bank database menggunakan National Center for Biotechnology Information Blast search tool. Hasil yang diperoleh ternyata ada dua basa yang berubah yaitu pada basa 24 dan basa 167. Pada basa 24 jelas terjadi subtitusi basa baru yaitu G, yang seharusnya tidak ada basa tersebut pada gen adhP-54 dan adhP-49 standar. Sedangkan pada basa 167 terjadi perbedaan basa dari seharusnya A pada standar menjadi G pada isolat 2.

  2. Molecular serotyping, virulence gene profiling and pathogenicity of Streptococcus agalactiae isolated from tilapia farms in Thailand by multiplex PCR.

    Science.gov (United States)

    Kannika, K; Pisuttharachai, D; Srisapoome, P; Wongtavatchai, J; Kondo, H; Hirono, I; Unajak, S; Areechon, N

    2017-06-01

    This study aimed to biotype Streptococcus agalactiae isolated from tilapia farms in Thailand based on molecular biotyping methods and to determine the correlation between the serotype and virulence of bacteria. In addition to a biotyping (serotyping) technique based on multiplex PCR of cps genes, in this study, we developed multiplex PCR typing of Group B streptococcus (GBS) virulence genes to examine three clusters of virulence genes and their correlation with the pathogenicity of S. agalactiae. The epidemiology of S. agalactiae in Thailand was analysed to provide bacterial genetic information towards a future rational vaccine strategy for tilapia culture systems. Streptococcus agalactiae were isolated from diseased tilapia from different areas of Thailand. A total of 124 S. agalactiae isolates were identified by phenotypic analysis and confirmed by 16S rRNA PCR. Bacterial genotyping was conducted based on (i) molecular serotyping of the capsular polysaccharide (cps) gene cluster and (ii) virulence gene profiling using multiplex PCR analysis of 14 virulence genes (lmb, scpB, pavA, cspA, spb1, cyl, bca, rib, fbsA, fbsB, cfb, hylB, bac and pbp1A/ponA). Only serotypes Ia and III were found in this study; serotype Ia lacks the lmb, scpB and spb1 genes, whereas serotype III lacks only the bac gene. Virulence tests in juvenile Nile tilapia demonstrated a correlation between the pathogenicity of the bacteria and their virulence gene profile, with serotype III showing higher virulence than serotype Ia. Epidemiological analysis showed an almost equal distribution in all regions of Thailand, except serotype III was found predominantly in the southern areas. Only two serotypes of S. agalactiae were isolated from diseased tilapia in Thailand. Serotype Ia showed fewer virulence genes and lower virulence than serotype III. Both serotypes showed a similar distribution throughout Thailand. We identified two major serotypes of S. agalactiae isolates associated with the outbreak in

  3. Complete genome sequence of an attenuated Sparfloxacin resistant Streptococcus agalactiae strain 138spar

    Science.gov (United States)

    Through selection of resistance to sparfloxacin, an attenuated Streptococcus agalactiae strain 138spar was obtained from its virulent parent strain S. agalactiae 138P. The full genome of S. agalactiae 138spar is 1,838,126 bp. The availability of this genome will allow comparative genomics to identi...

  4. Pathogenicity of Human ST23 Streptococcus agalactiae to Fish and Genomic Comparison of Pathogenic and Non-pathogenic Isolates

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2017-10-01

    Full Text Available Streptococcus agalactiae, or Group B Streptococcus (GBS, is a major pathogen causing neonatal sepsis and meningitis, bovine mastitis, and fish meningoencephalitis. CC23, including its namesake ST23, is not only the predominant GBS strain derived from human and cattle, but also can infect a variety of homeothermic and poikilothermic species. However, it has never been characterized in fish. This study aimed to determine the pathogenicity of ST23 GBS to fish and explore the mechanisms causing the difference in the pathogenicity of ST23 GBS based on the genome analysis. Infection of tilapia with 10 human-derived ST23 GBS isolates caused tissue damage and the distribution of pathogens within tissues. The mortality rate of infection was ranged from 76 to 100%, and it was shown that the mortality rate caused by only three human isolates had statistically significant difference compared with fish-derived ST7 strain (P < 0.05, whereas the mortality caused by other seven human isolates did not show significant difference compared with fish-derived ST7 strain. The genome comparison and prophage analysis showed that the major genome difference between virulent and non-virulent ST23 GBS was attributed to the different prophage sequences. The prophage in the P1 region contained about 43% GC and encoded 28–39 proteins, which can mediate the acquisition of YafQ/DinJ structure for GBS by phage recombination. YafQ/DinJ belongs to one of the bacterial toxin–antitoxin (TA systems and allows cells to cope with stress. The ST23 GBS strains carrying this prophage were not pathogenic to tilapia, but the strains without the prophage or carrying the pophage that had gene mutation or deletion, especially the deletion of YafQ/DinJ structure, were highly pathogenic to tilapia. In conclusion, human ST23 GBS is highly pathogenic to fish, which may be related to the phage recombination.

  5. Immunogenic properties of Streptococcus agalactiae FbsA fragments.

    Directory of Open Access Journals (Sweden)

    Salvatore Papasergi

    Full Text Available Several species of Gram-positive bacteria can avidly bind soluble and surface-associated fibrinogen (Fng, a property that is considered important in the pathogenesis of human infections. To gain insights into the mechanism by which group B Streptococcus (GBS, a frequent neonatal pathogen, interacts with Fng, we have screened two phage displayed genomic GBS libraries. All of the Fng-binding phage clones contained inserts encoding fragments of FbsA, a protein displaying multiple repeats. Since the functional role of this protein is only partially understood, representative fragments were recombinantly expressed and analyzed for Fng binding affinity and ability to induce immune protection against GBS infection. Maternal immunization with 6pGST, a fragment containing five repeats, significantly protected mouse pups against lethal GBS challenge and these protective effects could be recapitulated by administration of anti-6pGST serum from adult animals. Notably, a monoclonal antibody that was capable of neutralizing Fng binding by 6pGST, but not a non-neutralizing antibody, could significantly protect pups against lethal GBS challenge. These data suggest that FbsA-Fng interaction promotes GBS pathogenesis and that blocking such interaction is a viable strategy to prevent or treat GBS infections.

  6. Capsular typing of Streptococcus agalactiae (Lancefield group B streptococci) from fish using multiplex PCR and serotyping

    Science.gov (United States)

    Streptococcus spp. including Streptococcus agalactiae (Lancefield group B streptococci) are considered emerging pathogens responsible for approximately $1 billion USD in annual losses to the global tilapia (Oreochromis sp.) aquaculture industry. This study evaluated a published multiplex PCR capsul...

  7. Field trial about occurrence and relevance of streptococcus agalactiae in Mauritanian camels

    OpenAIRE

    Ould Habiboullah, Habiboullah

    2010-01-01

    The objective of this study was to determine the presence and prevalence of Streptococcus (S.) agalactiae in Mauritanian camels. Twenty seven camel herds from 8 Mauritanian regions were included in the study, whereby a total of 276 milk samples and 104 udder skin swaps were investigated for S. agalactiae. S. agalactiae was isolated from 25 out of 27 investigated camel herds. A total of 41 S. agalactiae strains where isolated, 29 isolates from the milk samples and 12 isolates from the udd...

  8. Relevance of Peptide Uptake Systems to the Physiology and Virulence of Streptococcus agalactiae

    OpenAIRE

    Samen, Ulrike; Gottschalk, Birgit; Eikmanns, Bernhard J.; Reinscheid, Dieter J.

    2004-01-01

    Streptococcus agalactiae is a major cause of invasive infections in human newborns. To satisfy its growth requirements, S. agalactiae takes up 9 of the 20 proteinogenic amino acids from the environment. Defined S. agalactiae mutants in one or several of four putative peptide permease systems were constructed and tested for peptide uptake, growth in various media, and expression of virulence traits. Oligopeptide uptake by S. agalactiae was shown to be mediated by the ABC transporter OppA1-F, w...

  9. Structural Differences between the Streptococcus agalactiae Housekeeping and Pilus-Specific Sortases: SrtA and SrtC1

    Energy Technology Data Exchange (ETDEWEB)

    Khare, B.; Krishnan, V.; Rajashankar, K.R.; I-Hsiu, H.; Xin, M.; Ton-That, H.; Narayana, S.V. (Texas-HSC); (Cornell); (UAB)

    2011-10-21

    The assembly of pili on the cell wall of Gram-positive bacteria requires transpeptidase enzymes called sortases. In Streptococcus agalactiae, the PI-1 pilus island of strain 2603V/R encodes two pilus-specific sortases (SrtC1 and SrtC2) and three pilins (GBS80, GBS52 and GBS104). Although either pilus-specific sortase is sufficient for the polymerization of the major pilin, GBS80, incorporation of the minor pilins GBS52 and GBS104 into the pilus structure requires SrtC1 and SrtC2, respectively. The S. agalactiae housekeeping sortase, SrtA, whose gene is present at a different location and does not catalyze pilus polymerization, was shown to be involved in cell wall anchoring of pilus polymers. To understand the structural basis of sortases involved in such diverse functions, we determined the crystal structures of S. agalactiae SrtC1 and SrtA. Both enzymes are made of an eight-stranded beta-barrel core with variations in their active site architecture. SrtA exhibits a catalytic triad arrangement similar to that in Streptococcus pyogenes SrtA but different from that in Staphylococcus aureus SrtA. In contrast, the SrtC1 enzyme contains an N-terminal helical domain and a 'lid' in its putative active site, which is similar to that seen in Streptococcus pneumoniae pilus-specific sortases, although with subtle differences in positioning and composition. To understand the effect of such differences on substrate recognition, we have also determined the crystal structure of a SrtC1 mutant, in which the conserved DP(W/F/Y) motif was replaced with the sorting signal motif of GBS80, IPNTG. By comparing the structures of WT wild type SrtA and SrtC1 and the 'lid' mutant of SrtC1, we propose that structural elements within the active site and the lid may be important for defining the role of specific sortase in pili biogenesis.

  10. Structural differences between the Streptococcus agalactiae housekeeping and pilus-specific sortases: SrtA and SrtC1.

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    B Khare

    Full Text Available The assembly of pili on the cell wall of Gram-positive bacteria requires transpeptidase enzymes called sortases. In Streptococcus agalactiae, the PI-1 pilus island of strain 2603V/R encodes two pilus-specific sortases (SrtC1 and SrtC2 and three pilins (GBS80, GBS52 and GBS104. Although either pilus-specific sortase is sufficient for the polymerization of the major pilin, GBS80, incorporation of the minor pilins GBS52 and GBS104 into the pilus structure requires SrtC1 and SrtC2, respectively. The S. agalactiae housekeeping sortase, SrtA, whose gene is present at a different location and does not catalyze pilus polymerization, was shown to be involved in cell wall anchoring of pilus polymers. To understand the structural basis of sortases involved in such diverse functions, we determined the crystal structures of S. agalactiae SrtC1 and SrtA. Both enzymes are made of an eight-stranded beta-barrel core with variations in their active site architecture. SrtA exhibits a catalytic triad arrangement similar to that in Streptococcus pyogenes SrtA but different from that in Staphylococcus aureus SrtA. In contrast, the SrtC1 enzyme contains an N-terminal helical domain and a 'lid' in its putative active site, which is similar to that seen in Streptococcus pneumoniae pilus-specific sortases, although with subtle differences in positioning and composition. To understand the effect of such differences on substrate recognition, we have also determined the crystal structure of a SrtC1 mutant, in which the conserved DP(W/F/Y motif was replaced with the sorting signal motif of GBS80, IPNTG. By comparing the structures of WT wild type SrtA and SrtC1 and the 'lid' mutant of SrtC1, we propose that structural elements within the active site and the lid may be important for defining the role of specific sortase in pili biogenesis.

  11. nalisis Keragaman Genetik Streptococcus agalactiae Penyebab Mastitis Subklinis Pada Sapi Perah Menggunakan pulsed field gel electrophoresis (PFGE) = Genetic Analysis of Streptococcus agalactiae Caused Subclinical ...

    OpenAIRE

    Trihastuti, Agnesia Endang

    2012-01-01

    Streptococcus agalactiae atau Streptokokus grup B (SGB) adalah salah satu bakteri utama penyebab mastitis subklinis pada sapi perch dan merupakan parasit obligat pada ambing. Karakterisasi S.agalactiae biasanya dilakukan secara konvensional menggunakan metode serotyping. Meslci metode ini sering digunakan namun masih mempunyai kelemahan apalagi masih adanya isolat S.agalactiae yang belum dapat dimasukkan ke dalam serotipe yang ada (nontypeable/NT), oleh karena itu pendekatan bare denga...

  12. Assignment of Streptococcus agalactiae isolates to clonal complexes using a small set of single nucleotide polymorphisms

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    Gilbert Gwendolyn L

    2008-08-01

    Full Text Available Abstract Background Streptococcus agalactiae (Group B Streptococcus (GBS is an important human pathogen, particularly of newborns. Emerging evidence for a relationship between genotype and virulence has accentuated the need for efficient and well-defined typing methods. The objective of this study was to develop a single nucleotide polymorphism (SNP based method for assigning GBS isolates to multilocus sequence typing (MLST-defined clonal complexes. Results It was found that a SNP set derived from the MLST database on the basis of maximisation of Simpsons Index of Diversity provided poor resolution and did not define groups concordant with the population structure as defined by eBURST analysis of the MLST database. This was interpreted as being a consequence of low diversity and high frequency horizontal gene transfer. Accordingly, a different approach to SNP identification was developed. This entailed use of the "Not-N" bioinformatic algorithm that identifies SNPs diagnostic for groups of known sequence variants, together with an empirical process of SNP testing. This yielded a four member SNP set that divides GBS into 10 groups that are concordant with the population structure. A fifth SNP was identified that increased the sensitivity for the clinically significant clonal complex 17 to 100%. Kinetic PCR methods for the interrogation of these SNPs were developed, and used to genotype 116 well characterized isolates. Conclusion A five SNP method for dividing GBS into biologically valid groups has been developed. These SNPs are ideal for high throughput surveillance activities, and combining with more rapidly evolving loci when additional resolution is required.

  13. Emerging trends in invasive and noninvasive isolates of Streptococcus agalactiae in a Latin American hospital: a 17-year study.

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    Crespo-Ortiz, Maria del Pilar; Castañeda-Ramirez, Claudia Rocio; Recalde-Bolaños, Monica; Vélez-Londoño, Juan Diego

    2014-08-03

    Streptococcus agalactiae or group B Streptococcus (GBS) has been recognized as a lethal pathogen in neonates worldwide. S. agalactiae infections also severely affect pregnant women and immunosuppressed adults with substantial attributable morbidity and mortality. However, in Latin America, studies on the epidemiology and behaviour of S. agalactiae infections remain limited. To better understand the behaviour of S. agalactiae infections in our region, we conducted a retrospective study to phenotypically describe S. agalactiae isolates collected in one of the largest hospitals in Colombia at two time periods: 1994-2001 and 2004-2012. The isolates were identified by biochemical analysis and tested for antimicrobial susceptibility. In 1994-2001 a total of 201 S. agalactiae isolates were found in urine 38.3%, vaginal exudates 27.8%, soft tissue 12.9%, and blood 8.5%. Susceptibility to ampicillin or penicillin was 94% whereas resistance to erythromycin and clindamycin were 2.8% and 5.2% respectively. In total 46 culture-positive cases of invasive infections were reported, 11 (24%) in neonates and 35 (76%) in adults. In 2004-2012 a total of 671 isolates were found in urine 47.8%, vaginal exudates 32.6%, soft tissue 2.7% and blood 9%. Susceptibility rates to ampicillin and penicillin were 98% whereas resistance to erythromycin and clindamycin were 12.5% and 9.4%. A total of 95 severe infections were reported: 12 (12.6%) were in neonates, 5 (5.3%) in children and 78 (82.1%) in adults. Over the 17-year study period the averaged prevalence of invasive S. agalactiae isolates was 17.4%. The estimated incidence for neonatal infections was 1.34 per 1000 livebirths (0.99 × 1000 livebirths for early- onset disease and 0.35 × 1000 livebirths for late- onset disease) whereas for non-pregnant adults the estimated incidence was 0.75 × 1000 admissions. A remarkable increase in bloodstream infections in immunosuppressed adults and a shift to early neonatal S. agalactiae infections

  14. Spring forward with improved Nile tilapia Oreochromis niloticus resistant to Streptococcus iniae and Streptococcus agalactiae IB

    Science.gov (United States)

    Tilapia aquaculture worldwide is valued around US $ 7 billion. Tilapia are an important source of protein for domestic (top 5 most consumed seafoods) and global food security. Two gram postitive bacteria, Streptococcus iniae and S. agalactiae, are responsible for billion dollar losses annually. Gen...

  15. Comparison of transmission dynamics between Streptococcus uberis and Streptococcus agalactiae intramammary infections.

    Science.gov (United States)

    Leelahapongsathon, Kansuda; Schukken, Ynte Hein; Pinyopummintr, Tanu; Suriyasathaporn, Witaya

    2016-02-01

    The objectives of study were to determine the transmission parameters (β), durations of infection, and basic reproductive numbers (R0) of both Streptococcus agalactiae and Streptococcus uberis as pathogens causing mastitis outbreaks in dairy herds. A 10-mo longitudinal study was performed using 2 smallholder dairy herds with mastitis outbreaks caused by Strep. agalactiae and Strep. uberis, respectively. Both herds had poor mastitis control management and did not change their milking management during the entire study period. Quarter milk samples were collected at monthly intervals from all lactating animals in each herd for bacteriological identification. The durations of infection for Strep. uberis intramammary infection (IMI) and Strep. agalactiae IMI were examined using Kaplan-Meier survival curves, and the Kaplan-Meier survival functions for Strep. uberis IMI and Strep. agalactiae IMI were compared using log rank survival-test. The spread of Strep. uberis and Strep. agalactiae through the population was determined by transmission parameter, β, the probability per unit of time that one infectious quarter will infect another quarter, assuming that all other quarters are susceptible. For the Strep. uberis outbreak herd (31 cows), 56 new infections and 28 quarters with spontaneous cure were observed. For the Strep. agalactiae outbreak herd (19 cows), 26 new infections and 9 quarters with spontaneous cure were observed. The duration of infection for Strep. agalactiae (mean=270.84 d) was significantly longer than the duration of infection for Strep. uberis (mean=187.88 d). The transmission parameters (β) estimated (including 95% confidence interval) for Strep. uberis IMI and Strep. agalactiae IMI were 0.0155 (0.0035-0.0693) and 0.0068 (0.0008-0.0606), respectively. The R0 (including 95% confidence interval) during the study were 2.91 (0.63-13.47) and 1.86 (0.21-16.61) for Strep. uberis IMI and Strep. agalactiae IMI, respectively. In conclusion, the transmission

  16. Comparative genomics analysis of Streptococcus agalactiae reveals that isolates from cultured tilapia in China are closely related to the human strain A909.

    Science.gov (United States)

    Liu, Guangjin; Zhang, Wei; Lu, Chengping

    2013-11-11

    Streptococcus agalactiae, also referred to as Group B Streptococcus (GBS), is a frequent resident of the rectovaginal tract in humans, and a major cause of neonatal infection. In addition, S. agalactiae is a known fish pathogen, which compromises food safety and represents a zoonotic hazard. The complete genome sequence of the piscine S. agalactiae isolate GD201008-001 was compared with 14 other piscine, human and bovine strains to explore their virulence determinants, evolutionary relationships and the genetic basis of host tropism in S. agalactiae. The pan-genome of S. agalactiae is open and its size increases with the addition of newly sequenced genomes. The core genes shared by all isolates account for 50 ~ 70% of any single genome. The Chinese piscine isolates GD201008-001 and ZQ0910 are phylogenetically distinct from the Latin American piscine isolates SA20-06 and STIR-CD-17, but are closely related to the human strain A909, in the context of the clustered regularly interspaced short palindromic repeats (CRISPRs), prophage, virulence-associated genes and phylogenetic relationships. We identified a unique 10 kb gene locus in Chinese piscine strains. Isolates from cultured tilapia in China have a close genomic relationship with the human strain A909. Our findings provide insight into the pathogenesis and host-associated genome content of piscine S. agalactiae isolated in China.

  17. Molecular Characterization of Streptococcus agalactiae Isolates From Pregnant and Non-Pregnant Women at Yazd University Hospital, Iran.

    Science.gov (United States)

    Sadeh, Maryam; Firouzi, Roya; Derakhshandeh, Abdollah; Bagher Khalili, Mohammad; Kong, Fanrong; Kudinha, Timothy

    2016-02-01

    Streptococcus agalactiae (Group B streptococcus, GBS) that colonize the vaginas of pregnant women may occasionally cause neonatal infections. It is one of the most common causes of sepsis and meningitis in neonates and of invasive diseases in pregnant women. It can also cause infectious disease among immunocompromised individuals. The distribution of capsular serotypes and genotypes varies over time and by geographic era. The serotyping and genotyping data of GBS in Iranian pregnant and non-pregnant women seems very limited. The aim of this study was to investigate the GBS ‎molecular capsular serotype ‎and genotype distribution of pregnant and non-pregnant carrier ‎women at Yazd university hospital, in Iran.‎. In this cross-sectional study, a total of 100 GBS strains isolated from 237 pregnant and 413 non-pregnant women were investigated for molecular capsular serotypes and surface protein genes using the multiplex PCR assay. The Chi-square method was used for statistical analysis. Out of 650 samples, 100 (15.4%) were identified as GBS, with a predominance of capsular serotypes III (50%) [III-1 (49), III-3 (1)], followed by II (25%), Ia (12%), V (11%), and Ib (2%), which was similar with another study conducted in Tehran, Iran, but they had no serotype Ia in their report. The surface protein antigen genes distribution was rib (53%), epsilon (38%), alp2/3 (6%), and alpha-c (3%). The determination of serotype and surface proteins of GBS strains distribution would ‎be ‎relevant ‎for the future possible formulation of a GBS vaccine.

  18. Regulation of PI-2b Pilus Expression in Hypervirulent Streptococcus agalactiae ST-17 BM110.

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    Bruno Périchon

    Full Text Available The widely spread Streptococcus agalactiae (also known as Group B Streptococcus, GBS "hypervirulent" ST17 clone is strongly associated with neonatal meningitis. The PI-2b locus is mainly found in ST17 strains but is also present in a few non ST17 human isolates such as the ST-7 prototype strain A909. Here, we analysed the expression of the PI-2b pilus in the ST17 strain BM110 as compared to the non ST17 A909. Comparative genome analyses revealed the presence of a 43-base pair (bp hairpin-like structure in the upstream region of PI-2b operon in all 26 ST17 genomes, which was absent in the 8 non-ST17 strains carrying the PI-2b locus. Deletion of this 43-bp sequence in strain BM110 resulted in a 3- to 5-fold increased transcription of PI-2b. Characterization of PI-2b promoter region in A909 and BM110 strains was carried out by RNAseq, primer extension, qRT-PCR and transcriptional fusions with gfp as reporter gene. Our results indicate the presence of a single promoter (Ppi2b with a transcriptional start site (TSS mapped 37 bases upstream of the start codon of the first PI-2b gene. The large operon of 16 genes located upstream of PI-2b codes for the group B carbohydrate (also known as antigen B, a major constituent of the bacterial cell wall. We showed that the hairpin sequence located between antigen B and PI-2b operons is a transcriptional terminator. In A909, increased expression of PI-2b probably results from read-through transcription from antigen B operon. In addition, we showed that an extended 5' promoter region is required for maximal transcription of gfp as a reporter gene in S. agalactiae from Ppi2b promoter. Gene reporter assays performed in Lactococcus lactis strain NZ9000, a related non-pathogenic Gram-positive species, revealed that GBS-specific regulatory factors are required to drive PI-2b transcription. PI-2b expression is up-regulated in the BM110ΔcovR mutant as compared to the parental BM110 strain, but this effect is probably

  19. Human milk oligosaccharides inhibit growth of group B Streptococcus

    NARCIS (Netherlands)

    Lin, Ann E; Autran, Chloe A; Szyszka, Alexandra; Escajadillo, Tamara; Huang, Mia; Godula, Kamil; Prudden, Anthony R; Boons, Geert-Jan; Lewis, Amanda L; Doran, Kelly S; Nizet, Victor; Bode, Lars

    2017-01-01

    Streptococcus agalactiae (group B Streptococcus, GBS) is a leading cause of invasive bacterial infections in newborns, typically acquired vertically during childbirth secondary to maternal vaginal colonization. Human milk oligosaccharides (HMOs) have important nutritional and biological activities

  20. Streptococcus agalactiae in pregnancies complicated by preterm prelabor rupture of membranes.

    Science.gov (United States)

    Musilova, Ivana; Pliskova, Lenka; Kutova, Radka; Jacobsson, Bo; Paterova, Pavla; Kacerovsky, Marian

    2016-01-01

    The main aim of this study was to evaluate the presence of Streptococcus agalactiae (S. agalactiae) in the vagina and the amniotic fluid in pregnancies complicated by preterm prelabor rupture of membranes (PPROM). The next aim was to evaluate the incidence of S. agalactiae early onset sepsis in newborns from PPROM pregnancies, with respect to the presence of S. agalactiae in the vagina and the amniotic fluid. Singleton gestations with PPROM between 24 + 0 and 36 + 6 were included. A vaginal swab was obtained, and amniocentesis was performed at admission. The presence of S. agalactiae in the vagina and in the amniotic fluid was assessed by culture and by real-time polymerase chain reaction, respectively. In total, 336 women were included. The presence of S. agalactiae in the vaginal and amniotic fluid was found in 9% (31/336) and 1% (3/336) of women. One woman had S. agalactiae in the amniotic fluid but was negative for the presence of S. agalactiae in the vaginal fluid. Early onset neonatal sepsis developed in one newborn from pregnancies complicated by the presence of S. agalactiae in the amniotic fluid. The presence of S. agalactiae in the vagina and amniotic fluid complicated approximately each 10th and each 100th PPROM pregnancy. Cultivation-negative findings of S. agalactiae in the vagina did not exclude the positivity of the amniotic fluid for S. agalactiae and the development of early onset sepsis in newborns.

  1. Complete genome sequence of a virulent Streptococcus agalactiae strain 138P isolated from diseased Nile tilapia

    Science.gov (United States)

    Streptococcus agalactiae strain 138P was isolated from the kidney of diseased Nile tilapia in Idaho during a 2007 streptococcal disease outbreak. The full genome of S. agalactiae 138P is 1,838,716 bp. The availability of this genome will allow comparative genomics to identify genes for antigen disco...

  2. Development of live attenuated sparfloxacin-resistant Streptococcus agalactiae polyvalent vaccines to protect Nile tilapia

    Science.gov (United States)

    To develop attenuated bacteria as potential live vaccines, sparfloxacin was used in this study to modify 40 isolates of Streptococcus agalactiae. Majority of S. agalactiae used in this study were able to develop at least 80-fold resistance to sparfloxacin. When the virulence of the sparfloxacin-resi...

  3. The Comparison of Streptococcus agalactiae Isolated from Fish and Bovine using Multilocus Sequence Typing

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    ANGELA MARIANA LUSIASTUTI

    2013-12-01

    Full Text Available Multilocus sequence typing (MLST has greater utility for determining the recent ancestral lineage and the relatedness of individual strains. Group B streptococci (GBS is one of the major causes of subclinical mastitis of dairy cattle in several countries. GBS also sporadically causes epizootic infections in fish. The aim of this study was to compare the evolutionary lineage of fish and bovine isolates in relation to the S. agalactiae global population as a whole by comparing the MLST profiles. Twenty S. agalactiae isolates were obtained from dairy cattle and fish. PCR products were amplified with seven different oligonucleotide primer pairs designed from the NEM316 GBS genome sequence. Clone complexes demonstrated that bovine and fish isolates were separate populations. These findings lead us to conclude that fish S. agalactiae is not a zoonotic agent for bovine. MLST could help clarify the emergence of pathogenic clones and to decide whether the host acts as a reservoir for another pathogenic lineage.

  4. Streptococcus agalactiae impairs cerebral bioenergetics in experimentally infected silver catfish.

    Science.gov (United States)

    Baldissera, Matheus D; Souza, Carine F; Parmeggiani, Belisa S; Santos, Roberto C V; Leipnitz, Guilhian; Moreira, Karen L S; da Rocha, Maria Izabel U M; da Veiga, Marcelo L; Baldisserotto, Bernardo

    2017-10-01

    It is becoming evident that bacterial infectious diseases affect brain energy metabolism, where alterations of enzymatic complexes of the mitochondrial respiratory chain and creatine kinase (CK) lead to an impairment of cerebral bioenergetics which contribute to disease pathogenesis in the central nervous system (CNS). Based on this evidence, the aim of this study was to evaluate whether alterations in the activity of complex IV of the respiratory chain and CK contribute to impairment of cerebral bioenergetics during Streptococcus agalactiae infection in silver catfish (Rhamdia quelen). The activity of complex IV of the respiratory chain in brain increased, while the CK activity decreased in infected animals compared to uninfected animals. Brain histopathology revealed inflammatory demyelination, gliosis of the brain and intercellular edema in infected animals. Based on this evidence, S. agalactiae infection causes an impairment in cerebral bioenergetics through the augmentation of complex IV activity, which may be considered an adaptive response to maintain proper functioning of the electron respiratory chain, as well as to ensure ongoing electron flow through the electron transport chain. Moreover, inhibition of cerebral CK activity contributes to lower availability of ATP, contributing to impairment of cerebral energy homeostasis. In summary, these alterations contribute to disease pathogenesis linked to the CNS. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Growth, immune responses and protection of Nile tilapia Oreochromis niloticus immunized with formalin-killed Streptococcus agalactiae serotype Ia and III vaccines

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    Atchariya Suwannasang

    2017-08-01

    Full Text Available The protective efficacy of formalin-killed Streptococcus agalactiae (Group B Streptococcus, GBS serotype Ia (GBS-Ia and III (GBS-III vaccines were assessed in Nile tilapia (Oreochromis niloticus. The fish with an average weight of 34.45± 0.08 g were immunized by intraperitoneal (i.p. injection with 4 different formalin-killed vaccines prepared from GBS-Ia (1x1010 CFU/mL, GBS-III (1x1010 CFU/mL, and combined GBS-Ia and GBS-III in an equal volume at final concentrations 1x1010 CFU/mL and 2x1010 CFU/mL in comparison with the non-immunized control group. At 2 and 4 weeks post vaccination, no significant differences were observed (p>0.05 among treatments in growth performance or haemato-immunological parameters, except the increased red blood cell at 2 weeks. Significantly increased antibody titers (p<0.05 against GBS-Ia and GBS-III antigens were noted in the groups immunized with homologous GBS vaccines, whereas the group reacted with heterologous GBS antigen showed less antibody titer as compared with the control group. The vaccination experiment indicated that i.p. injection of Nile tilapia with formalin-killed cells prepared from GBS-Ia or GBS-III provides significant protection, with relative percent survival (RPS value of 52.17 to 71.42%, against a challenge with the homologous serotype isolate, whereas the RPS in fish challenged with a heterologous serotype isolate varied from 20.00 to 53.57%. These results suggested that vaccines from either GBS-Ia or GBS-III have insufficient cross-protective efficacy against the other serotypes. However, a mixed vaccine produced from both GBS serotypes Ia and III provided significant protection with 65.00 to 95.66% RPS which could be an excellent vaccine to protect fish against streptococcosis caused by both GBS serotypes Ia and III.

  6. Streptococcus Agalactiae Research on Secretion Vaginal and Anal Pregnant Women of a City of Paulista Northwest

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    Cátia Rezende

    2015-12-01

    Full Text Available Streptococcus agalactiae has great medical importance in infections associated with severe neonatal morbidity and mortality. It is the most frequent bacterium isolated from the tables of septicemia, pneumonia and neonatal meningitis. This study aimed to determine the prevalence of anal and vaginal colonization of S. agalactiae in pregnant women at different gestational ages. We evaluated the incidence of colonization by S. agalactiae in 129 pregnant women of any age. Two samples of secretion were collected for culture: a perianal swab and a vaginal swab. Each of the two swabs were inoculated in test tubes containing Todd-Hewitt broth and subcultured on blood agar. After a period of 24 to 48 hours, the colonies suggestive of S. agalactiae were submitted to morfotintorial analysis and to biochemical tests for identification. Among 129 women studied, 3 (2.33% have tested positive for Streptococcus agalactiae and 126 (97.67% were negative. The results presented in this work are inferior to the data from other studies, however, the methodology used was compatible with most authors. Even so this rate is considered a relevant value taking into account the importance of Streptococcus agalactiae infections in pregnant women and newborns, emphasizing the importance of encouraging the culture of vaginal and anal secretion for the detection of Streptococcus agalactiae in surveys of prenatal care.

  7. Poliartritis y tenosinovitis grave por Streptococcus agalactiae en un paciente con hipoesplenia funcional Severe polyarthritis and tenosynovitis caused by Streptococcus agalactiae in a patient with functional hyposplenia

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    Domingo C. Balderramo

    2002-08-01

    Full Text Available La artritis por Streptococcus agalactiae es infrecuente. No conocemos publicaciones de casos sobre la afección tendinosa por este microorganismo. Se presenta una mujer de 46 años que consultó por fiebre, poliartralgias, mialgias, diarrea y vómitos. Como antecedentes presentaba carcinoma papilar de tiroides e hipoesplenia funcional. Al examen se encontraba hemodinámicamente inestable, febril, con artritis de mano izquierda, muñecas, codos, hombro derecho y tobillo izquierdo. Presentaba tenosinovitis en ambos pies y en la mano izquierda. Los hemocultivos y el cultivo de la bursa olecraniana derecha fueron positivos para S. agalactiae. La ecografía mostró signos de tenosinovitis del tibial anterior izquierdo. Completó 20 días de tratamiento endovenoso con cefazolina y 12 días de cefuroxima oral. El cuadro articular revirtió completamente en 60 días. El Streptococcus agalactiae puede causar, en forma infrecuente, un síndrome de poliartritis, tenosinovitis y fiebre similar al producido por la infección gonocócica.Cases of arthritis caused by Streptococcus agalactiae are infrequent and in our knowledge there are no case reports of tenosynovitis caused by S. agalactiae. A 46-year-old woman presented with fever, polyarthralgia, myalgia, diarrhea and vomiting. She had a history of papillary thyroid carcinoma and functional hyposplenia. She was febrile, with arthritis in hands, wrists, elbows, right shoulder and left ankle joints, and presented tenosynovitis in both feet and left hand. Blood and right olecranon bursa sample cultures were positive for S. agalactiae. An ultrasound scan made at the musculus tibialis anterior of left foot revealed signs of tenosynovitis. She was treated with intravenous cefazolin for 20 days and oral cefuroxime for 12 days. The joint involvement completely subsided in 60 days. Streptococcus agalactiae can cause, infrequently, a polyarthritis and tenosynovitis syndrome similar to disseminated gonococcal

  8. Recolonization of group B Streptococcus (GBS) in women with prior GBS genital colonization in pregnancy.

    Science.gov (United States)

    Tam, Teresa; Bilinski, Ewa; Lombard, Emily

    2012-10-01

    The purpose of the study is to evaluate the incidence of women with prior GBS genital colonization who have recolonization in subsequent pregnancies. This is a retrospective, cohort study of patients with a prior GBS genital colonization in pregnancy and a subsequent pregnancy with a recorded GBS culture result, from January 2000 through June 2007. Documentation of GBS status was through GBS culture performed between 35 to 37 weeks gestation. Exclusion criteria included pregnancies with unknown GBS status, patients with GBS bacteriuria, women with a previous neonate with GBS disease and GBS finding prior to 35 weeks. Data was analyzed using SPSS 15.0. The sample proportion of subjects with GBS genital colonization and its confidence interval were computed to estimate the incidence rate. Logistic regression was performed to assess potential determinants of GBS colonization. Regression coefficients, odds ratios and associated confidence intervals, and p-values were reported, with significant results reported. There were 371 pregnancies that met the test criteria. There were 151 subsequent pregnancies with GBS genital colonization and 220 without GBS recolonization. The incidence of GBS recolonization on patients with prior GBS genital colonization was 40.7% (95% confidence interval 35.7-45.69%). The incidence rate for the sample was significantly larger than 30% (p recolonization in subsequent pregnancies.

  9. Loop-mediated isothermal amplification assay for rapid detection of Streptococcus agalactiae (group B streptococcus) in vaginal swabs - a proof of concept study.

    Science.gov (United States)

    McKenna, James Patrick; Cox, Ciara; Fairley, Derek John; Burke, Rachael; Shields, Michael D; Watt, Alison; Coyle, Peter Valentine

    2017-03-01

    Neonatal sepsis caused by Streptococcus agalactiae [group B streptococcus (GBS)] is a life-threatening condition, which is preventable if colonized mothers are identified and given antibiotic prophylaxis during labour. Conventional culture is time consuming and unreliable, and many available non-culture diagnostics are too complex to implement routinely at point of care. Loop-mediated isothermal amplification (LAMP) is a method that, enables the rapid and specific detection of target nucleic acid sequences in clinical materials without the requirement for extensive sample preparation. A prototype LAMP assay targeting GBS sip gene is described. The assay was 100 % specific for GBS, with a limit of detection of 14 genome copies per reaction. The clinical utility of the LAMP assay for rapid direct molecular detection of GBS was determined by testing a total of 157 vaginal swabs with minimal sample processing using a rapid lysis solution. Compared to a reference quantitative real-time PCR assay, the direct LAMP protocol had a sensitivity and specificity of 95.4 and 100 %, respectively, with positive and negative predictive values of 100 and 98.3 %, respectively. Positive and negative likelihood ratios were infinity and 0.05, respectively. The direct LAMP method required a mean time of 45 min from the receipt of a swab to generation of a confirmed result, compared to 2 h 30 min for the reference quantitative real-time PCR test. The direct LAMP protocol described is easy to perform, facilitating rapid and accurate detection of GBS in vaginal swabs. This test has a potential for use at point of care.

  10. Comparative genome analysis identifies two large deletions in the genome of highly-passaged attenuated Streptococcus agalactiae strain YM001 compared to the parental pathogenic strain HN016.

    Science.gov (United States)

    Wang, Rui; Li, Liping; Huang, Yan; Luo, Fuguang; Liang, Wanwen; Gan, Xi; Huang, Ting; Lei, Aiying; Chen, Ming; Chen, Lianfu

    2015-11-04

    Streptococcus agalactiae (S. agalactiae), also known as group B Streptococcus (GBS), is an important pathogen for neonatal pneumonia, meningitis, bovine mastitis, and fish meningoencephalitis. The global outbreaks of Streptococcus disease in tilapia cause huge economic losses and threaten human food hygiene safety as well. To investigate the mechanism of S. agalactiae pathogenesis in tilapia and develop attenuated S. agalactiae vaccine, this study sequenced and comparatively analyzed the whole genomes of virulent wild-type S. agalactiae strain HN016 and its highly-passaged attenuated strain YM001 derived from tilapia. We performed Illumina sequencing of DNA prepared from strain HN016 and YM001. Sequencedreads were assembled and nucleotide comparisons, single nucleotide polymorphism (SNP) , indels were analyzed between the draft genomes of HN016 and YM001. Clustered regularly interspaced short palindromic repeats (CRISPRs) and prophage were detected and analyzed in different S. agalactiae strains. The genome of S. agalactiae YM001 was 2,047,957 bp with a GC content of 35.61 %; it contained 2044 genes and 88 RNAs. Meanwhile, the genome of S. agalactiae HN016 was 2,064,722 bp with a GC content of 35.66 %; it had 2063 genes and 101 RNAs. Comparative genome analysis indicated that compared with HN016, YM001 genome had two significant large deletions, at the sizes of 5832 and 11,116 bp respectively, resulting in the deletion of three rRNA and ten tRNA genes, as well as the deletion and functional damage of ten genes related to metabolism, transport, growth, anti-stress, etc. Besides these two large deletions, other ten deletions and 28 single nucleotide variations (SNVs) were also identified, mainly affecting the metabolism- and growth-related genes. The genome of attenuated S. agalactiae YM001 showed significant variations, resulting in the deletion of 10 functional genes, compared to the parental pathogenic strain HN016. The deleted and mutated functional genes all

  11. Role of the Group B antigen of Streptococcus agalactiae: a peptidoglycan-anchored polysaccharide involved in cell wall biogenesis.

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    Élise Caliot

    Full Text Available Streptococcus agalactiae (Group B streptococcus, GBS is a leading cause of infections in neonates and an emerging pathogen in adults. The Lancefield Group B carbohydrate (GBC is a peptidoglycan-anchored antigen that defines this species as a Group B Streptococcus. Despite earlier immunological and biochemical characterizations, the function of this abundant glycopolymer has never been addressed experimentally. Here, we inactivated the gene gbcO encoding a putative UDP-N-acetylglucosamine-1-phosphate:lipid phosphate transferase thought to catalyze the first step of GBC synthesis. Indeed, the gbcO mutant was unable to synthesize the GBC polymer, and displayed an important growth defect in vitro. Electron microscopy study of the GBC-depleted strain of S. agalactiae revealed a series of growth-related abnormalities: random placement of septa, defective cell division and separation processes, and aberrant cell morphology. Furthermore, vancomycin labeling and peptidoglycan structure analysis demonstrated that, in the absence of GBC, cells failed to initiate normal PG synthesis and cannot complete polymerization of the murein sacculus. Finally, the subcellular localization of the PG hydrolase PcsB, which has a critical role in cell division of streptococci, was altered in the gbcO mutant. Collectively, these findings show that GBC is an essential component of the cell wall of S. agalactiae whose function is reminiscent of that of conventional wall teichoic acids found in Staphylococcus aureus or Bacillus subtilis. Furthermore, our findings raise the possibility that GBC-like molecules play a major role in the growth of most if not all beta-hemolytic streptococci.

  12. Antimicrobial resistance and molecular characteristics of Streptococcus agalactiae isolated from women of reproductive age

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    Magdalena Musiorska

    2016-12-01

    Full Text Available Introduction. Streptococcus agalactiae infections are among the most significant causes of neonatal invasive diseases. Proper screening and detection of pregnant women carrying GBS allows intrapartum administration of antibiotic prophylaxis and is an effective measure in preventing transmission of bacteria from mother to newborns. Material and methods. Sixty three bacterial strains were isolated from vaginal swabs from pregnant and nonpregnant women of reproductive age. Species were identified by colony morphology, haemolysis type, Gram staining and SLIDEX® Strepto Plus latex test. Antimicrobial resistance of 56 strains was determined using disk-diffusion method. The presence of molecular resistance determinants was assessed using PCR with specific primers, and capsular types were identified using multiplex PCR. Results. None of the strains were resistant to the first drug of choice, penicillin. A large percentage of isolates (78.6% were resistant to doxycycline. The prevalence of resistance to macrolides and lincosamides, antibiotics used in women allergic to penicillin, was high. Those results corresponded with PCR tests, as tetM and ermA1 were most frequently detected genes (98.4 and 87.3%, respectively. 7.94% of strains possessed 7 different out of 13 tested genes determining resistance to different groups of antimicrobials. Among the capsular types, Ia, which proved to be associated with the most severe and invasive infections in mothers and neonates, was the most prevalent (65.08%. Conclusions. Even though they are susceptible to penicillin, multidrug resistance is common among S. agalactiae strains isolated from women of reproductive age and this resistance can be caused by more than one gene per single isolate

  13. Endocytosis‒Mediated Invasion and Pathogenicity of Streptococcus agalactiae in Rat Cardiomyocyte (H9C2).

    Science.gov (United States)

    Pooja, Sharma; Pushpanathan, Muthuirulan; Gunasekaran, Paramasamy; Rajendhran, Jeyaprakash

    2015-01-01

    Streptococcus agalactiae infection causes high mortality in cardiovascular disease (CVD) patients, especially in case of setting prosthetic valve during cardiac surgery. However, the pathogenesis mechanism of S. agalactiae associate with CVD has not been well studied. Here, we have demonstrated the pathogenicity of S. agalactiae in rat cardiomyocytes (H9C2). Interestingly, both live and dead cells of S. agalactiae were uptaken by H9C2 cells. To further dissect the process of S. agalactiae internalization, we chemically inhibited discrete parts of cellular uptake system in H9C2 cells using genistein, chlorpromazine, nocodazole and cytochalasin B. Chemical inhibition of microtubule and actin formation by nocodazole and cytochalasin B impaired S. agalactiae internalization into H9C2 cells. Consistently, reverse‒ transcription PCR (RT‒PCR) and quantitative real time‒PCR (RT-qPCR) analyses also detected higher levels of transcripts for cytoskeleton forming genes, Acta1 and Tubb5 in S. agalactiae‒infected H9C2 cells, suggesting the requirement of functional cytoskeleton in pathogenesis. Host survival assay demonstrated that S. agalactiae internalization induced cytotoxicity in H9C2 cells. S. agalactiae cells grown with benzyl penicillin reduced its ability to internalize and induce cytotoxicity in H9C2 cells, which could be attributed with the removal of surface lipoteichoic acid (LTA) from S. agalactiae. Further, the LTA extracted from S. agalactiae also exhibited dose‒dependent cytotoxicity in H9C2 cells. Taken together, our data suggest that S. agalactiae cells internalized H9C2 cells through energy‒dependent endocytic processes and the LTA of S. agalactiae play major role in host cell internalization and cytotoxicity induction.

  14. Prevalence of the colonization by Streptococcus agalactiae in pregnant women from a public health system in Santo Ângelo – RS

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    Franciane Rios Senger

    2016-01-01

    Full Text Available ABSTRACT: Background and Objectives: Streptococcus agalactiae (GBS is part of the female genital tract microbiota, however, its clinical significance is related to infections in newborns and can cause severe cases of pneumonia, septicemia and meningitis. Thus, the aim of this study is to determine the prevalence of colonization by S. agalactiae in pregnant women and analyze the sensitivity profile of the isolated front of antimicrobials. Methods: Vaginal and anorectal samples of pregnant women over 30 weeks of gestation were collected from February to June 2013. The samples were stored in Stuart transport medium and then inoculated in Todd-Hewitt broth added gentamicin and acid nalidixic with subsequent subculture on blood agar plates. For identification were performed Gram test, catalase, CAMP and latex agglutination. Furthermore, the antimicrobial susceptibility tests and the test for the detection of resistance induced clindamycin in the samples resistant to erythromycin were conducted. They are also assessed, through interviews, demographic, socioeconomic and clinical and obstetric data. Results: It was observed colonization in 22.5% (18/80 of the pregnant women. The strains were sensitive to most of the antibiotics tested except erythromycin, showing a resistance of 22.2% (4/18 isolates. However, none of the samples erythromycin resistant had induced resistance to clindamycin. Conclusion: The high maternal colonization by S. agalactiae found emphasize the importance of isolation of this bacterium in late pregnancy, preventing the occurrence of neonatal infection. KEYWORDS: Streptococcus agalactiae. Pregnancy. Prevalence.

  15. Severe infective endocarditis in a healthy adult due to Streptococcus agalactiae.

    Science.gov (United States)

    Fujita, Hiroaki; Nakamura, Itaru; Tsukimori, Ayaka; Sato, Akihiro; Ohkusu, Kiyofumi; Matsumoto, Tetsuya

    2015-09-01

    A case of severe endocarditis, with complications of multiple infarction, meningitis, and ruptured mitral chordae tendineae, caused by Streptococcus agalactiae in a healthy man, is reported. Emergency cardiovascular surgery was performed on the day of admission. Infective endocarditis caused by S. agalactiae is very rare, particularly in a healthy adult. In addition, microbiological analysis revealed that S. agalactiae of sequence type (ST) 19, which belongs to serotype III, was present in the patient's vegetation, mitral valve, and blood culture. It was therefore concluded that the endocarditis was caused by ST19, which has been reported as a non-invasive type of S. agalactiae. This was an extremely rare case in which S. agalactiae of ST19 caused very severe endocarditis in an adult patient with no underlying disease. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Streptococcus agalactiae Inhibits Candida albicans Hyphal Development and Diminishes Host Vaginal Mucosal TH17 Response

    OpenAIRE

    Xiao-Yu Yu; Fei Fu; Wen-Na Kong; Qian-Kun Xuan; Dong-Hua Wen; Xiao-Qing Chen; Yong-Ming He; Li-Hua He; Jian Guo; Ai-Ping Zhou; Yang-Hong Xi; Li-Jun Ni; Yu-Feng Yao; Wen-Juan Wu

    2018-01-01

    Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans, and that EFG1-Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC), the...

  17. Binding of glycoprotein Srr1 of Streptococcus agalactiae to fibrinogen promotes attachment to brain endothelium and the development of meningitis.

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    Ho Seong Seo

    Full Text Available The serine-rich repeat glycoprotein Srr1 of Streptococcus agalactiae (GBS is thought to be an important adhesin for the pathogenesis of meningitis. Although expression of Srr1 is associated with increased binding to human brain microvascular endothelial cells (hBMEC, the molecular basis for this interaction is not well defined. We now demonstrate that Srr1 contributes to GBS attachment to hBMEC via the direct interaction of its binding region (BR with human fibrinogen. When assessed by Far Western blotting, Srr1 was the only protein in GBS extracts that bound fibrinogen. Studies using recombinant Srr1-BR and purified fibrinogen in vitro confirmed a direct protein-protein interaction. Srr1-BR binding was localized to amino acids 283-410 of the fibrinogen Aα chain. Structural predictions indicated that the conformation of Srr1-BR is likely to resemble that of SdrG and other related staphylococcal proteins that bind to fibrinogen through a "dock, lock, and latch" mechanism (DLL. Deletion of the predicted latch domain of Srr1-BR abolished the interaction of the BR with fibrinogen. In addition, a mutant GBS strain lacking the latch domain exhibited reduced binding to hBMEC, and was significantly attenuated in an in vivo model of meningitis. These results indicate that Srr1 can bind fibrinogen directly likely through a DLL mechanism, which has not been described for other streptococcal adhesins. This interaction was important for the pathogenesis of GBS central nervous system invasion and subsequent disease progression.

  18. Development of live attenuated Streptococcus agalactiae as potential vaccines by selecting for resistance to sparfloxacin.

    Science.gov (United States)

    Pridgeon, Julia W; Klesius, Phillip H

    2013-05-31

    To develop attenuated bacteria as potential live vaccines, sparfloxacin was used in this study to modify 40 isolates of Streptococcus agalactiae. Majority of S. agalactiae used in this study were able to develop at least 80-fold resistance to sparfloxacin. When the virulence of the sparfloxacin-resistant S. agalactiae isolates were tested in 10-12g Nile tilapia by intraperitoneal injection at dose of 2×10(7)CFU/fish, 31 were found to be avirulent to fish. Of the 31 avirulent sparfloxacin-resistant S. agalactiae isolates, 30 provided 75-100% protection to 10-12g Nile tilapia against challenges with a virulent S. agalactiae isolate Sag 50. When the virulence of the 30 sparfloxacin-resistant S. agalactiae isolates was tested in 3-5g Nile tilapia by intraperitoneal injection at dose of 2×10(7)CFU/fish, six were found to be avirulent to 3-5g Nile tilapia. Of the six avirulent sparfloxacin-resistant S. agalactiae isolates, four provided 3-5g Nile tilapia 100% protection against challenges with homologous isolates, including Sag 97-spar isolate that was non-hemolytic. However, Sag 97-spar failed to provide broad cross-protection against challenges with heterologous isolates. When Nile tilapia was vaccinated with a polyvalent vaccine consisting of 30 sparfloxacin-resistant S. agalactiae isolates at dose of 2×10(6)CFU/fish, the polyvalent vaccine provided significant (PS. agalactiae. Taken together, our results suggest that a polyvalent vaccine consisting of various strains of S. agalactiae might be essential to provide broader protection to Nile tilapia against infections caused by S. agalactiae. Published by Elsevier Ltd.

  19. Acute Neonatal Parotitis with Late-Onset Septic Shock due to Streptococcus agalactiae

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    M. Boulyana

    2014-01-01

    Full Text Available Acute neonatal parotitis (ANP is a very rare disease. Most cases are managed conservatively; early antibiotics and adequate hydration may reduce the need for surgery. The most common cause of ANP is Staphylococcus aureus. We report a rare case of acute neonatal parotitis with late-onset septic shock due to Streptococcus agalactiae. The diagnosis was confirmed with ultrasound and isolation of Streptococcus agalactiae from blood culture. The patient was treated successfully with 10 days of intravenous antibiotics and supportive measures. Despite being rare, streptococcal ANP should be considered in the etiological diagnosis of neonatal sepsis. Early diagnosis and appropriate antibiotic might prevent serious complications.

  20. In silico analysis of candidate proteins sharing homology with Streptococcus agalactiae proteins and their role in male infertility.

    Science.gov (United States)

    Parida, Rajeshwari; Samanta, Luna

    2017-02-01

    leukocytospermia/bacteriospermia induced male factor infertility but also open new avenues for immunocontraception. AA: amino acid; ASA: antisperm antibodies; GBS: group B streptococcus; HLA: human leukocyte antigen; HAS3: hyaluronan synthase 3: IEDB: immune epitope database; MAPO2: O 6 -methylguanine-induced apoptosis 2; MHC: major histocompatibility complex; ROS: reactive oxygen species; Rosbin1: round spermatid basic protein 1; S. agalactiae: Streptococcus agalactiae;SA: sperm antigen; SPATA17: spermatogenesis associated protein17; SPNR: spermatid perinuclear RNA binding protein; TEX15: testis-expressed sequence 15 protein; TOPAZ: testis- and ovary-specific PAZ domain-containing protein; TPABP: testis-specific poly-A binding protein; TPAP: testis-specific poly(A) polymerase; WHO: World Health Organization.

  1. Infecciones por Streptococcus agalactiae en un servicio de neonatología abierto Infections due to Streptococcus agalactiae at an open neonatology service

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    Manuel Díaz Álvarez

    2008-12-01

    Full Text Available INTRODUCCIÓN. El objetivo del presente estudio fue conocer las características clínicas y epidemiológicas de las infecciones por estreptococo del grupo B en recién nacidos egresados de los hospitales maternos. MÉTODOS. Se realizó un estudio descriptivo, que incluyó a recién nacidos consecutivos con infecciones por Streptococcus agalactiae, ingresados en el Servicio de Neonatología del Hospital Pediátrico Universitario «Juan M. Márquez» entre febrero de 1992 y diciembre del 2007. Se procesaron y analizaron distintas variables clínicas y epidemiológicas, con cálculo de tasas de incidencia y letalidad, así como relación entre variables categóricas. RESULTADOS. Hubo 76 recién nacidos con infección por Streptococcus agalactiae, lo cual constituyó una tasa promedio anual de 1,9 x 100 ingresos. Predominaron las infecciones de inicio tardío y las adquiridas en la comunidad (89,5 % y 93,4 %, respectivamente. La meningitis fue la forma clínica más frecuente, seguida de la bacteriemia aislada. Hubo 56 de 76 recién nacidos con bacteriemia (73,7 %. El Streptococcus agalactiae tuvo elevada sensibilidad ante la penicilina, la eritromicina, la vancomicina, la cefotaxima y el cloranfenicol. Hubo 7 fallecidos (9,2 % y todos fueron pacientes con infección del sistema nervioso central. CONCLUSIONES. Streptococcus agalactiae es un agente causal de infecciones que afectan al recién nacido, tanto en la comunidad como en el medio hospitalario. Estas infecciones pueden ser letales en algunos pacientes con infección del sistema nervioso central con bacteriemia o sin ella, aún manteniendo un patrón de elevada susceptibilidad a los antibióticos betalactámicos.INTRODUCCIÓN. The objective of the present study was to know the clinical and epidemiological characteristics of the infections caused by group B Streptococcus in newborns discharged from maternal hospitals. METHODS. A descriptive study that included consecutive infants with

  2. Multiple Evolutionary Selections Involved in Synonymous Codon Usages in the Streptococcus agalactiae Genome.

    Science.gov (United States)

    Ma, Yan-Ping; Ke, Hao; Liang, Zhi-Ling; Liu, Zhen-Xing; Hao, Le; Ma, Jiang-Yao; Li, Yu-Gu

    2016-02-24

    Streptococcus agalactiae is an important human and animal pathogen. To better understand the genetic features and evolution of S. agalactiae, multiple factors influencing synonymous codon usage patterns in S. agalactiae were analyzed in this study. A- and U-ending rich codons were used in S. agalactiae function genes through the overall codon usage analysis, indicating that Adenine (A)/Thymine (T) compositional constraints might contribute an important role to the synonymous codon usage pattern. The GC3% against the effective number of codon (ENC) value suggested that translational selection was the important factor for codon bias in the microorganism. Principal component analysis (PCA) showed that (i) mutational pressure was the most important factor in shaping codon usage of all open reading frames (ORFs) in the S. agalactiae genome; (ii) strand specific mutational bias was not capable of influencing the codon usage bias in the leading and lagging strands; and (iii) gene length was not the important factor in synonymous codon usage pattern in this organism. Additionally, the high correlation between tRNA adaptation index (tAI) value and codon adaptation index (CAI), frequency of optimal codons (Fop) value, reinforced the role of natural selection for efficient translation in S. agalactiae. Comparison of synonymous codon usage pattern between S. agalactiae and susceptible hosts (human and tilapia) showed that synonymous codon usage of S. agalactiae was independent of the synonymous codon usage of susceptible hosts. The study of codon usage in S. agalactiae may provide evidence about the molecular evolution of the bacterium and a greater understanding of evolutionary relationships between S. agalactiae and its hosts.

  3. Comparative proteome analysis of two Streptococcus agalactiae strains from cultured tilapia with different virulence.

    Science.gov (United States)

    Li, Wei; Su, You-Lu; Mai, Yong-Zhan; Li, Yan-Wei; Mo, Ze-Quan; Li, An-Xing

    2014-05-14

    Streptococcus agalactiae is a major piscine pathogen, which causes significant morbidity and mortality among numerous fish species, and results in huge economic losses to aquaculture. Many S. agalactiae strains showing different virulence characteristics have been isolated from infected tilapia in different geographical regions throughout South China in the recent years, including natural attenuated S. agalactiae strain TFJ0901 and virulent S. agalactiae strain THN0901. In the present study, survival of tilapia challenged with S. agalactiae strain TFJ0901 and THN0901 (10(7)CFU/fish) were 93.3% and 13.3%, respectively. Moreover, there are severe lesions of the examined tissues in tilapia infected with strain THN0901, but no significant histopathological changes were observed in tilapia infected with the strain TFJ0901. In order to elucidate the factors responsible for the invasive potential of S. agalactiae between two strains TFJ0901 and THN0901, a comparative proteome analysis was applied to identify the different protein expression profiles between the two strains. 506 and 508 cellular protein spots of S. agalactiae TFJ0901 and THN0901 were separated by two dimensional electrophoresis, respectively. And 34 strain-specific spots, corresponding to 27 proteins, were identified successfully by MALDI-TOF mass spectrometry. Among them, 23 proteins presented exclusively in S. agalactiae TFJ0901 or THN0901, and the other 4 proteins presented in different isomeric forms between TFJ0901 and THN0901. Most of the strain-specific proteins were just involved in metabolic pathways, while 7 of them were presumed to be responsible for the virulence differences of S. agalactiae strain TFJ0901 and THN0901, including molecular chaperone DnaJ, dihydrolipoamide dehydrogenase, thioredoxin, manganese-dependent inorganic pyrophosphatase, elongation factor Tu, bleomycin resistance protein and cell division protein DivIVA. These virulence-associated proteins may contribute to identify new

  4. Streptococcus agalactiae infection in cancer patients: a five-year study.

    Science.gov (United States)

    Pimentel, B A S; Martins, C A S; Mendonça, J C; Miranda, P S D; Sanches, G F; Mattos-Guaraldi, A L; Nagao, P E

    2016-06-01

    Although the highest burden of Streptococcus agalactiae infections has been reported in industrialized countries, studies on the characterization and epidemiology are still limited in developing countries and implementation of control strategies remains undefined. The aim of this retrospective study was to assess the epidemiological, clinical, and microbiological aspects of S. agalactiae infections in cancer patients treated at a Reference Brazilian National Cancer Institute - INCA, Rio de Janeiro, Brazil. We reviewed the clinical and laboratory records of all cancer patients identified as having invasive S. agalactiae disease during 2010-2014. The isolates were identified by biochemical analysis and tested for antimicrobial susceptibility. A total of 263 strains of S. agalactiae were isolated from cancer patients who had been clinically and microbiologically classified as infected. S. agalactiae infections were mostly detected among adults with solid tumors (94 %) and/or patients who have used indwelling medical devices (77.2 %) or submitted to surgical procedures (71.5 %). Mortality rates (in-hospital mortality during 30 days after the identification of S. agalactiae) related to invasive S. agalactiae infections (n = 28; 31.1 %) for the specific category of neoplasic diseases were: gastrointestinal (46 %), head and neck (25 %), lung (11 %), hematologic (11 %), gynecologic (4 %), and genitourinary (3 %). We also found an increase in S. agalactiae resistance to erythromycin and clindamycin and the emergence of penicillin-less susceptible isolates. A remarkable number of cases of invasive infections due to S. agalactiae strains was identified, mostly in adult patients. Our findings reinforce the need for S. agalactiae control measures in Brazil, including cancer patients.

  5. Preventing invasive Group B Streptococcus (GBS) disease in South ...

    African Journals Online (AJOL)

    9 No. 3 has been successfully used for the prevention of tetanus, influenza and pertussis in infants.[11] A trivalent GBS polysaccharide-protein conjugate vaccine (against serotypes Ia, Ib and III) has completed phase-II evaluation among pregnant women and has the potential to prevent 70 - 80% of all invasive GBS disease.

  6. Central nervous system involvement in adult patients with invasive infection caused by Streptococcus agalactiae.

    Science.gov (United States)

    Oyanguren, B; Esteban, L; Guillán, M; de Felipe, A; Alonso Cánovas, A; Navas, E; Quereda, C; Corral, I

    2015-04-01

    Streptococcus agalactiae is frequently an asymptomatic coloniser and a cause of neonatal and puerperal sepsis. Infections in nonpregnant adults are uncommon. The frequency of neurological complications caused by invasive infection with this microorganism in adults remains unknown. Here, we study the frequency and characteristics of central nervous system (CNS) involvement in adults with invasive S. agalactiae infection. Review of all adults with invasive S. agalactiae infection between 2003 and 2011 in a tertiary hospital. S. agalactiae was isolated from blood, CSF or synovial fluid in 75 patients. Among them, 7 (9,3%) displayed neurological involvement: 5 men and 2 nonpregnant women, aged between 20 and 62 years. Diagnoses were spinal epidural abscess due to spondylodiscitis with spinal cord compression; acute bacterial meningitis; ischemic stroke as presentation of bacterial endocarditis (2 patients each); and meningoventriculitis after neurosurgery and ventricular shunting. One patient with endocarditis caused by S. agalactiae and S. aureus died in the acute phase, and another died 3 months later from metastatic cancer. The other patients recovered without sequelae. All patients had systemic predisposing factors for infection and 5 (71,4%) had experienced disruption of the mucocutaneous barrier as a possible origin of the infection. CNS involvement is not uncommon in adult patients with invasive infection caused by S. agalactiae. Isolating S. agalactiae, especially in cases of meningitis, should lead doctors to search for predisposing systemic disease and causes of mucocutaneous barrier disruption. Copyright © 2013 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

  7. Visualization of the role of host heme on the virulence of the heme auxotroph Streptococcus agalactiae.

    Science.gov (United States)

    Joubert, Laetitia; Dagieu, Jean-Baptiste; Fernandez, Annabelle; Derré-Bobillot, Aurélie; Borezée-Durant, Elise; Fleurot, Isabelle; Gruss, Alexandra; Lechardeur, Delphine

    2017-01-16

    Heme is essential for several cellular key functions but is also toxic. Whereas most bacterial pathogens utilize heme as a metabolic cofactor and iron source, the impact of host heme during bacterial infection remains elusive. The opportunist pathogen Streptococcus agalactiae does not synthesize heme but still uses it to activate a respiration metabolism. Concomitantly, heme toxicity is mainly controlled by the HrtBA efflux transporter. Here we investigate how S. agalactiae manages heme toxicity versus benefits in the living host. Using bioluminescent bacteria and heme-responsive reporters for in vivo imaging, we show that the capacity of S. agalactiae to overcome heme toxicity is required for successful infection, particularly in blood-rich organs. Host heme is simultaneously required, as visualized by a generalized infection defect of a respiration-negative mutant. In S. agalactiae, HrtBA expression responds to an intracellular heme signal via activation of the two-component system HssRS. A hssRS promoter-driven intracellular luminescent heme sensor was designed to identify host compartments that supply S. agalactiae with heme. S. agalactiae acquires heme in heart, kidneys, and liver, but not in the brain. We conclude that S. agalactiae response to heme is organ-dependent, and its efflux may be particularly relevant in late stages of infection.

  8. Molecular characterization of Streptococcus agalactiae and Streptococcus uberis isolates from bovine milk.

    Science.gov (United States)

    Shome, Bibek Ranjan; Bhuvana, Mani; Mitra, Susweta Das; Krithiga, Natesan; Shome, Rajeswari; Velu, Dhanikachalam; Banerjee, Apala; Barbuddhe, Sukhadeo B; Prabhudas, Krishnamshetty; Rahman, Habibar

    2012-12-01

    Streptococci are one among the major mastitis pathogens which have a considerable impact on cow health, milk quality, and productivity. The aim of the present study was to investigate the occurrence and virulence characteristics of streptococci from bovine milk and to assess the molecular epidemiology and population structure of the Indian isolates using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Out of a total of 209 bovine composite milk samples screened from four herds (A-D), 30 Streptococcus spp. were isolated from 29 milk samples. Among the 30 isolates, species-specific PCR and partial 16S rRNA gene sequence analysis identified 17 Streptococcus agalactiae arising from herd A and 13 Streptococcus uberis comprising of 5, 7, and 1 isolates from herds B, C, and D respectively. PCR based screening for virulence genes revealed the presence of the cfb and the pavA genes in 17 and 1 S. agalactiae isolates, respectively. Similarly, in S. uberis isolates, cfu gene was present in six isolates from herd C, the pau A/skc gene in all the isolates from herds B, C, and D, whereas the sua gene was present in four isolates from herd B and the only isolate from herd D. On MLST analysis, all the S. agalactiae isolates were found to be of a novel sequence type (ST), ST-483, reported for the first time and is a single locus variant of the predicted subgroup founder ST-310, while the S. uberis isolates were found to be of three novel sequence types, namely ST-439, ST-474, and ST-475, all reported for the first time. ST-474 was a double locus variant of three different STs of global clonal complex ST-143 considered to be associated with clinical and subclinical mastitis, but ST-439 and ST-475 were singletons. Unique sequence types identified for both S. agalactiae and S. uberis were found to be herd specific. On PFGE analysis, identical or closely related restriction patterns for S. agalactiae ST-483 and S. uberis ST-439 in herds A and B

  9. Development of a colloidal gold immunochromatographic strip for rapid detection of Streptococcus agalactiae in tilapia.

    Science.gov (United States)

    Wen-de, Wu; Min, Li; Ming, Chen; Li-Ping, Li; Rui, Wang; Hai-Lan, Chen; Fu-Yan, Chen; Qiang, Mi; Wan-Wen, Liang; Han-Zhong, Chen

    2017-05-15

    A colloidal gold immunochromatographic strip was developed for rapid detection of Streptococcus agalactiae (S. agalactiae) infection in tilapia. The monoclonal antibodies (mAb) 4C12 and 3A9 were used to target S. agalactiae as colloidal gold-mAb conjugate and captured antibody, respectively. The colloidal gold immunochromatographic strip was assembled via routine procedures. Optimal pH and minimum antibody levels in the reaction system for gold colloidal-mAb 4C12 conjugation were pH 7.4 and 18μg/mL, respectively. Optimal concentrations of the captured antibody 3A9 and goat anti-mouse antibody were 0.6mg/mL and 2mg/mL, respectively. The sensitivity of the strip for detecting S. agalactiae was 1.5×10 5 colony forming units (CFU). No cross-reaction was observed with other commonly encountered bacteria, including Pseudomonas fluorescens, Aeromonas hydrophila, Vibrio anguillarum and Streptococcus iniae. The assay time for S. agalactiae was less than 15min. Tilapia samples artificially infected with S. agalactiae were tested using the newly developed strip. The results indicated that blood, brain, kidney, spleen, metanephros and intestine specimens of infected fish can be used for S. agalactiae detection. The validity of the strip was maintained for 6 months at 4°C. These findings suggested that the immunochromatographic strip was effective for spot and rapid detection of S. agalactiae infected tilapia. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Complete genome sequence of an attenuated Sparfloxacin-resistant Streptococcus agalactiae strain 138spar

    Science.gov (United States)

    The complete genome of a sparfloxacin-resistant Streptococcus agalactiae vaccine strain 138spar is 1,838,126 bp in size. The genome has 1892 coding sequences and 82 RNAs. The annotation of the genome is added by the NCBI Prokaryotic Genome Annotation Pipeline. The publishing of this genome will allo...

  11. TOKSISITAS PROTEIN 89 kDa PRODUK EKSTRASELULER Streptococcus agalactiae PADA IKAN NILA (Oreochromis niloticus

    Directory of Open Access Journals (Sweden)

    Amrullah Amrullah

    2015-09-01

    Full Text Available Identifikasi protein toksin yang bersifat antigenik dari produk ekstraselular (ECP crude Streptococcus agalactiae penting dilakukan untuk pengembangan vaksin protein toksoid. Penelitian ini bertujuan untuk mengevaluasi toksisitas protein dengan berat molekul 89 kDa dari ECP Streptococcus agalactiae hasil fraksinasi dengan SDS-PAGE (ECPP89. Ikan nila dengan bobot sekitar 25 g masing-masing diinjeksi secara intraperitonial dengan protein ECPP89 dosis 1, 2, 4, 8, dan 16 μg/mL/ekor ikan (secara berturut-turut diberi kode ECPP89-1, ECPP89-2, ECPP89-4, ECPP89-8, dan ECPP89-16. Sebagai kontrol positif ikan diinjeksi dengan bakteri utuh S. agalactiae 1 x 104 cfu/mL (WCB dan ECP crude S. agalactiae (ECPC, sementara kontrol negatif ikan diinjeksi larutan PBS. Ikan dipelihara selama 15 hari dengan kepadatan 10 ekor (70 L air. Hasil penelitian menunjukkan bahwa ikan nila yang diinjeksi dengan ECPP89 mengalami gejala seperti perubahan morfologi, perubahan nafsu makan, dan perubahan renang ikan. Mortalitas pada perlakuan ECPP89 secara umum lebih tinggi dibandingkan dengan ECPC, namun lebih rendah (p<0,05 dibandingkan dengan WCB. Mortalitas ikan pada perlakuan ECPP89-4, ECPP89-8, dan ECPP89-16 tidak berbeda tetapi secara signifikan lebih tinggi dibandingkan dengan ECPC dan dua dosis perlakuan ECPP89 lainnya (p<0,05. Ikan kontrol negatif tidak mengalami kematian maupun perubahan klinis. Hasil ini menunjukkan bahwa ECPP89 merupakan protein toksin dari ECP S. agalactiae.

  12. Whole-cell vaccine of Streptococcus agalactiae in Oreochromis sp. with immersion method

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    , Sukenda

    2015-05-01

    Full Text Available ABSTRACT The study was aimed to evaluate the efficacy of formalin-killed non-hemolytic Streptococcus agalactiae N14G and NK1 isolates whole-killed vaccine to prevent streptococcosis in tilapia. Ten fishes were reared in a tank 60x30x35 cm3 with an average body weight at 10.79±0.99 g. Fish was vaccinated through bath immersion at a concentration of 109 cfu/mL. Fish was subsequently challenged by intraperitonial injection of Streptococcus agalactiae 105 cfu/mL at 11 days post-vaccination. Parameters observed were survival, relative percent survival (RPS, total leukocyte, phagocytic activity, antibody titer, total erythrocyte, haemoglobin level, haematocrit level, dan water quality. Samplings were performed in day-0, 20, and 30 after vaccination. Both vaccines have shown higher survival (60% and RPS (40% when challenged with pathogenic Streptococcus N14G isolates than other treatments. Based on RPS percentage observed, those vaccine were still not sufficiently effective to combat S. agalactiae infection. Keywords: tilapia, bath immersion, Streptococcus agalactiae, whole-cell vaccine ABSTRAK Penelitian ini bertujuan untuk mengevaluasi efikasi vaksin formalin-killed cell Streptococcus agalactiae tipe isolat nonhemolitik N14G dan NK1 se utuh yang diberikan melalui perendaman dalam mencegah penyakit streptococcosis pada ikan nila. Ikan nila yang digunakan memiliki bobot 10,79±0,99 g, dipelihara sebanyak sepuluh ekor dalam akuarium ukuran 60x30x35 cm3. Ikan divaksinasi dengan metode perendaman dengan dosis 109 cfu/mL. Uji tantang dilakukan pada hari ke-11 pascavaksinasi dengan dosis 105 cfu/mL. Parameter yang diamati meliputi sintasan (SR, sintasan relatif/relative percent survival (RPS, total leukosit, aktivitas fagositik, titer antibodi, total eritrosit, kadar hemoglobin, kadar hematokrit, dan kualitas air. Pengamatan parameter dilakukan pada hari ke-0, ke-10, ke-20, dan ke-30. Hasil penelitian menunjukkan perlakuan kedua vaksin yang diinfeksi

  13. The β-hemolysin and intracellular survival of Streptococcus agalactiae in human macrophages.

    Science.gov (United States)

    Sagar, Anubha; Klemm, Carolin; Hartjes, Lara; Mauerer, Stefanie; van Zandbergen, Ger; Spellerberg, Barbara

    2013-01-01

    S. agalactiae (group B streptococci, GBS) is a major microbial pathogen in human neonates and causes invasive infections in pregnant women and immunocompromised individuals. The S. agalactiae β-hemolysin is regarded as an important virulence factor for the development of invasive disease. To examine the role of β-hemolysin in the interaction with professional phagocytes, the THP-1 monocytic cell line and human granulocytes were infected with a serotype Ia S. agalactiae wild type strain and its isogenic nonhemolytic mutant. We could show that the nonhemolytic mutants were able to survive in significantly higher numbers than the hemolytic wild type strain, in THP-1 macrophage-like cells and in assays with human granulocytes. Intracellular bacterial multiplication, however, could not be observed. The hemolytic wild type strain stimulated a significantly higher release of Tumor Necrosis Factor-α than the nonhemolytic mutant in THP-1 cells, while similar levels of the chemokine Interleukin-8 were induced. In order to investigate bacterial mediators of IL-8 release in this setting, purified cell wall preparations from both strains were tested and found to exert a potent proinflammatory stimulus on THP-1 cells. In conclusion, our results indicate that the β-hemolysin has a strong influence on the intracellular survival of S. agalactiae and that a tightly controlled regulation of β-hemolysin expression is required for the successful establishment of S. agalactiae in different host niches.

  14. The β-Hemolysin and Intracellular Survival of Streptococcus agalactiae in Human Macrophages

    Science.gov (United States)

    Sagar, Anubha; Klemm, Carolin; Hartjes, Lara; Mauerer, Stefanie; van Zandbergen, Ger; Spellerberg, Barbara

    2013-01-01

    S. agalactiae (group B streptococci, GBS) is a major microbial pathogen in human neonates and causes invasive infections in pregnant women and immunocompromised individuals. The S. agalactiae β-hemolysin is regarded as an important virulence factor for the development of invasive disease. To examine the role of β-hemolysin in the interaction with professional phagocytes, the THP-1 monocytic cell line and human granulocytes were infected with a serotype Ia S. agalactiae wild type strain and its isogenic nonhemolytic mutant. We could show that the nonhemolytic mutants were able to survive in significantly higher numbers than the hemolytic wild type strain, in THP-1 macrophage-like cells and in assays with human granulocytes. Intracellular bacterial multiplication, however, could not be observed. The hemolytic wild type strain stimulated a significantly higher release of Tumor Necrosis Factor-α than the nonhemolytic mutant in THP-1 cells, while similar levels of the chemokine Interleukin-8 were induced. In order to investigate bacterial mediators of IL-8 release in this setting, purified cell wall preparations from both strains were tested and found to exert a potent proinflammatory stimulus on THP-1 cells. In conclusion, our results indicate that the β-hemolysin has a strong influence on the intracellular survival of S. agalactiae and that a tightly controlled regulation of β-hemolysin expression is required for the successful establishment of S. agalactiae in different host niches. PMID:23593170

  15. The β-hemolysin and intracellular survival of Streptococcus agalactiae in human macrophages.

    Directory of Open Access Journals (Sweden)

    Anubha Sagar

    Full Text Available S. agalactiae (group B streptococci, GBS is a major microbial pathogen in human neonates and causes invasive infections in pregnant women and immunocompromised individuals. The S. agalactiae β-hemolysin is regarded as an important virulence factor for the development of invasive disease. To examine the role of β-hemolysin in the interaction with professional phagocytes, the THP-1 monocytic cell line and human granulocytes were infected with a serotype Ia S. agalactiae wild type strain and its isogenic nonhemolytic mutant. We could show that the nonhemolytic mutants were able to survive in significantly higher numbers than the hemolytic wild type strain, in THP-1 macrophage-like cells and in assays with human granulocytes. Intracellular bacterial multiplication, however, could not be observed. The hemolytic wild type strain stimulated a significantly higher release of Tumor Necrosis Factor-α than the nonhemolytic mutant in THP-1 cells, while similar levels of the chemokine Interleukin-8 were induced. In order to investigate bacterial mediators of IL-8 release in this setting, purified cell wall preparations from both strains were tested and found to exert a potent proinflammatory stimulus on THP-1 cells. In conclusion, our results indicate that the β-hemolysin has a strong influence on the intracellular survival of S. agalactiae and that a tightly controlled regulation of β-hemolysin expression is required for the successful establishment of S. agalactiae in different host niches.

  16. Population structure and virulence gene profiles of Streptococcus agalactiae collected from different hosts worldwide.

    Science.gov (United States)

    Morach, Marina; Stephan, Roger; Schmitt, Sarah; Ewers, Christa; Zschöck, Michael; Reyes-Velez, Julian; Gilli, Urs; Del Pilar Crespo-Ortiz, María; Crumlish, Margaret; Gunturu, Revathi; Daubenberger, Claudia A; Ip, Margaret; Regli, Walter; Johler, Sophia

    2018-03-01

    Streptococcus agalactiae is a leading cause of morbidity and mortality among neonates and causes severe infections in pregnant women and nonpregnant predisposed adults, in addition to various animal species worldwide. Still, information on the population structure of S. agalactiae and the geographical distribution of different clones is limited. Further data are urgently needed to identify particularly successful clones and obtain insights into possible routes of transmission within one host species and across species borders. We aimed to determine the population structure and virulence gene profiles of S. agalactiae strains from a diverse set of sources and geographical origins. To this end, 373 S. agalactiae isolates obtained from humans and animals from five different continents were typed by DNA microarray profiling. A total of 242 different S. agalactiae strains were identified and further analyzed. Particularly successful clonal lineages, hybridization patterns, and strains were identified that were spread across different continents and/or were present in more than one host species. In particular, several strains were detected in both humans and cattle, and several canine strains were also detected in samples from human, bovine, and porcine hosts. The findings of our study suggest that although S. agalactiae is well adapted to various hosts including humans, cattle, dogs, rodents, and fish, interspecies transmission is possible and occurs between humans and cows, dogs, and rabbits. The virulence and resistance gene profiles presented enable new insights into interspecies transmission and make a crucial contribution to the identification of suitable targets for therapeutic agents and vaccines.

  17. Phosphoglycerate kinase enhanced immunity of the whole cell of Streptococcus agalactiae in tilapia, Oreochromis niloticus.

    Science.gov (United States)

    Wang, Yi-Ting; Huang, Hsing-Yen; Tsai, Ming-An; Wang, Pei-Chi; Jiang, Bo-Huang; Chen, Shih-Chu

    2014-12-01

    Streptococcus agalactiae is a Gram-positive bacterium and a severe aquaculture pathogen that can infect a wide range of warmwater fish species. The outer-surface proteins in bacterial pathogens play an important role in pathogenesis. We evaluated the immunogenicity of two of the identified surface proteins namely phosphoglycerate kinase (PGK) and ornithine carbamoyl-transferase (OCT). PGK and OCT were over-expressed and purified from Escherichia coli and used as the subunit vaccines in tilapia. Tilapia immunized with the S. agalactiae modified bacteria vaccine (whole cell preparations with recombinant PGK and OCT proteins) individually were tested for the efficacy. OCT and PGK combined with WC had a higher survival rate. A high-level protection and significant specific antibody responses against S. agalactiae challenge was observed upon the vaccinated tilapia with the purified PGK protein and S. agalactiae whole cells. The specific antibody titer against S. agalactiae antigen suggested that increased antibody titers were correlated with post-challenge survival rate. Il-1β expression profile was higher in PGK + WC-treated group. Tnf-α expression in the PGK + WC group was significantly increased. Taken together, our results suggested the combinations of recombinant protein and whole cell may elicit immune responses that reach greater protection than that of individual S. agalactiae components. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. GC-MS-Based Metabolome and Metabolite Regulation in Serum-Resistant Streptococcus agalactiae.

    Science.gov (United States)

    Wang, Zhe; Li, Min-Yi; Peng, Bo; Cheng, Zhi-Xue; Li, Hui; Peng, Xuan-Xian

    2016-07-01

    Streptococcus agalactiae causes severe systemic infections in human and fish. In the present study, we established a pathogen-plasma interaction model by which we explored how S. agalactiae evaded serum-mediated killing. We found that S. agalactiae grew faster in the presence of yellow grouper plasma than in the absence of the plasma, indicating S. agalactiae evolved a way of evading the fish immune system. To determine the events underlying this phenotype, we applied GC-MS-based metabolomics approaches to identify differential metabolomes between S. agalactiae cultured with and without yellow grouper plasma. Through bioinformatics analysis, decreased malic acid and increased adenosine were identified as the most crucial metabolites that distinguish the two groups. Meanwhile, they presented with decreased TCA cycle and elevated purine metabolism, respectively. Finally, exogenous malic acid and adenosine were used to reprogram the plasma-resistant metabolome, leading to elevated and decreased susceptibility to the plasma, respectively. Therefore, our findings reveal for the first time that S. agalactiae utilizes a metabolic trick to respond to plasma killing as a result of serum resistance, which may be reverted or enhanced by exogenous malic acid and adenosine, respectively, suggesting that the metabolic trick can be regulated by metabolites.

  19. Novel substrate specificity of glutathione synthesis enzymes from Streptococcus agalactiae and Clostridium acetobutylicum

    International Nuclear Information System (INIS)

    Kino, Kuniki; Kuratsu, Shoko; Noguchi, Atsushi; Kokubo, Masahiro; Nakazawa, Yuji; Arai, Toshinobu; Yagasaki, Makoto; Kirimura, Kohtaro

    2007-01-01

    Glutathione (GSH) is synthesized by γ-glutamylcysteine synthetase (γ-GCS) and glutathione synthetase (GS) in living organisms. Recently, bifunctional fusion protein, termed γ-GCS-GS catalyzing both γ-GCS and GS reactions from gram-positive firmicutes Streptococcus agalactiae, has been reported. We revealed that in the γ-GCS activity, S. agalactiae γ-GCS-GS had different substrate specificities from those of Escherichia coli γ-GCS. Furthermore, S. agalactiae γ-GCS-GS synthesized several kinds of γ-glutamyltripeptide, γ-Glu-X aa -Gly, from free three amino acids. In Clostridium acetobutylicum, the genes encoding γ-GCS and putative GS were found to be immediately adjacent by BLAST search, and had amino acid sequence homology with S. agalactiae γ-GCS-GS, respectively. We confirmed that the proteins expressed from each gene showed γ-GCS and GS activity, respectively. C. acetobutylicum GS had broad substrate specificities and synthesized several kinds of γ-glutamyltripeptide, γ-Glu-Cys-X aa . Whereas the substrate specificities of γ-GCS domain protein and GS domain protein of S. agalactiae γ-GCS-GS were the same as those of S. agalactiae γ-GCS-GS

  20. Inapparent Streptococcus agalactiae infection in adult/commercial tilapia.

    Science.gov (United States)

    Sun, Jiufeng; Fang, Wei; Ke, Bixia; He, Dongmei; Liang, Yuheng; Ning, Dan; Tan, Hailing; Peng, Hualin; Wang, Yunxin; Ma, Yazhou; Ke, Changwen; Deng, Xiaoling

    2016-05-24

    We report on inapparent infections in adult/commercial tilapia in major tilapia fish farms in Guangdong. A total of 146 suspected isolates were confirmed to be S. agalactiae using an API 20 Strep system and specific PCR amplification. All isolates were identified as serotype Ia using multiplex serotyping PCR. An MLST assay showed single alleles of adhP (10), atr (2), glcK (2), glnA (1), pheS (1), sdhA (3) and tkt (2), and this profile was designated 'unique ST 7'. The analysis of virulence genes resulted in 10 clusters, of which dltr-bca-sodA-spb1-cfb-bac (62, 42.47%) was the predominant virulence gene profile. The PFGE analysis of S. agalactiae yielded 6 distinct PFGE types (A, B, C, D, F and G), of which Pattern C (103) was the predominant type, accounting for approximately 70.55% (103/146) of the total S. agalactiae strains. Therefore, unlike what has been found in juvenile tilapia, in which PFGE pattern D/F is the major prevalent pattern, we found that pattern C was the major prevalent pattern in inapparent infected adult/commercial tilapia in Guangdong, China. In conclusion, we close a gap in the current understanding of S. agalactiae epidemiology and propose that researchers should be alert for inapparent S. agalactiae infections in adult/commercial tilapia to prevent a potential threat to food safety.

  1. Molecular characteristics of Streptococcus agalactiae in a mother-baby prospective cohort study: Implication for vaccine development and insights into vertical transmission.

    Science.gov (United States)

    Li, Shunming; Wen, Guoming; Cao, Xuelian; Guo, Dan; Yao, Zhenjiang; Wu, Chuan'an; Ye, Xiaohua

    2018-04-05

    Streptococcus agalactiae (GBS) is a leading cause of neonatal sepsis and meningitis in many countries. This study aimed to determine the molecular characteristics of GBS colonized in mothers and their infants so as to provide implication for vaccine strategies and confirm vertical transmission. A prospective cohort study was conducted to recruit 1815 mother-neonate pairs. All GBS isolates from pregnant women and her infants were tested for serotypes, multilocus sequence types and virulence genes. The relationship between multiple molecular characteristics of GBS isolates was tested by the correspondence analysis, and the agreement between mother-neonate paired data in molecular characteristics was analyzed using Kappa tests. The predominant serotypes were III, Ia and V, and the most prevalent sequence types (STs) were ST19, ST17, ST10, and ST12. All isolates carried at least one pilus island (PI). The most common combination of PIs was PI-2b alone, followed by PI-1+PI-2a and PI-2a alone, and the most prevalent alpha-like protein (alp) genes were rib, epsilon and alphaC. Moreover, a strong relationship was noted between STs, serotypes, alp genes and PIs, including ST17 associated with serotype-III/rib/PI-2b, ST19 with serotype-III/rib/PI-1+PI-2a, and ST485 with serotype-Ia/epsilon/PI-2b. The rate of GBS vertical transmission was 14.1%, and the kappa test revealed good agreement in multiple molecular characteristics among GBS-positive mother-neonate pairs. Notably, the switching of molecular characteristics was found during vertical transmission. Our findings underscore the value of monitoring multiple molecular characteristics so as to provide implication for multivalent strategies and gain insights into GBS vertical transmission and vertical characteristic switching. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Infective Endocarditis Complicated by Intraventricular Abscesses, Pericarditis, and Mycotic Aneurysm Due to an Emerging Strain of Serotype VI Streptococcus agalactiae.

    Science.gov (United States)

    Hirai, Nobuyasu; Kasahara, Kei; Uno, Kenji; Ogawa, Yoshihiko; Ogawa, Taku; Yonekawa, Shinsuke; Nakano, Ryuichi; Yano, Hisakazu; Sakagami, Azusa; Uemura, Takayuki; Okura, Hiroyuki; Saito, Yoshihiko; Yoshikawa, Masahide; Mikasa, Keiichi

    2017-11-22

    An increasing number of invasive infections due to Streptococcus agalactiae in non-pregnant adults have been reported. We report a case of infective endocarditis complicated by intraventricular abscesses, pericarditis, and mycotic aneurysm due to S. agalactiae belonging to ST681 with a capsular serotype VI in a woman with diabetes. The patient also had a myocardial infarction and was treated with percutaneous coronary intervention, pericardiocentesis, and 6 weeks of antibiotic treatment. Invasive infections due to serotype VI S. agalactiae are common in Asian countries such as Taiwan and Japan, so continuous monitoring of invasive S. agalactiae strains is warranted.

  3. The Evaluation of Antibacterial Activity (Streptococcus agalactiae by Using Mahkota Dewa Extract (Phaleria macrocarpa L. with Diffirent Solvent

    Directory of Open Access Journals (Sweden)

    Lutfiana Safitri

    2017-07-01

    Full Text Available This research was aimed to determine the antibacterial activity of mahkota dewa extract and the effective concentration of mahkota dewa extract against Streptococcus agalactiae. This research was conducted from 2Mayth to 2Juneth 2016. The material ware Streptococcus agalactiae bacteria which isolated from mastitis milk, mahkota dewa which extracted using Aquades and ethanol. The method design was experiment research using Nested Design with 6 treatments and 5 replications. The concentrations of the treatments were P1 (10%, P2 (20%, P3 (30%, P4 (40% and P5 (50% and positive control P0 (iodips 10%. The collected data were analyzed using the analysis of variance indicated the significant effects, the least significant different test (LSD was then employed. Mahkota dewa extract using ethanol (50% result showed that significantly (P<0.01 on growth of Streptococcus agalactiae was 20.34± 0.92mm. Mahkota dewa extract using aquades (50% result showed that significantly (P<0.01 on growth of Streptococcus agalactiae was 10.0 ± 0.50 mm. The conclusion of this research is Mahkota dewa fruits extract with ethanol had inhibitory higher in habiting the Streptococcus agalactiae bacteria compared to aquades solvent. The best of treatment of Mahkota dewa fruits extract with ethanol and Aquades solvent in concentration 50% had a high ability to inhibit the growth of Streptococcus agalactiae.

  4. Experimental early pathogenesis of Streptococcus agalactiae infection in red tilapia Oreochromis spp.

    Science.gov (United States)

    Iregui, C A; Comas, J; Vásquez, G M; Verján, N

    2016-02-01

    Streptococcus agalactiae causes a severe systemic disease in fish, and the routes of entry are still ill-defined. To address this issue, two groups of 33 red tilapia Oreochromis spp. each of 10 g were orally infected with S. agalactiae (n = 30), and by immersion (n = 30), six individuals were control-uninfected fish. Three tilapias were killed at each time point from 30 min to 96 h post-inoculation (pi); controls were killed at 96 h. Samples from most tissues were examined by haematoxylin-eosin (H&E), indirect immunoperoxidase (IPI) and periodic acid-Schiff; only intestine from fish infected by gavage was evaluated by transmission electron microscopy. The results of both experiments suggest that the main entry site of S. agalactiae in tilapia is the gastrointestinal epithelium; mucus seems to play an important defensive role, and environmental conditions may be an important predisposing factor for the infection. © 2015 John Wiley & Sons Ltd.

  5. Streptococcus agalactiae endocarditis presenting as acalculous cholecystitis in a previously well woman.

    LENUS (Irish Health Repository)

    Brewer, Linda

    2013-01-01

    This case report describes the unusual presentation of a previously very well woman with Streptococcus agalactiae endocarditis in the emergency department. History, examination and preliminary laboratory and radiological investigations supported a diagnosis of acalculous cholecystitis, for which she was given intravenous broad spectrum antimicrobial therapy. One day following admission, the patient deteriorated and became unresponsive. Subsequent MRI of the brain revealed multiple bihemispheric cerebral emboli and a large, mobile mitral valve thrombus was visualised on her transoesophageal echocardiogram. S agalactiae was cultured from venous blood samples and her antimicrobial cover was adjusted accordingly. Despite her presumed guarded prognosis, this patient made a remarkable recovery. To our knowledge, the association of S agalactiae endocarditis with acalculous cholecystitis has not been previously described.

  6. The highly dynamic CRISPR1 system of Streptococcus agalactiae controls the diversity of its mobilome.

    Science.gov (United States)

    Lopez-Sanchez, Maria-José; Sauvage, Elisabeth; Da Cunha, Violette; Clermont, Dominique; Ratsima Hariniaina, Elisoa; Gonzalez-Zorn, Bruno; Poyart, Claire; Rosinski-Chupin, Isabelle; Glaser, Philippe

    2012-09-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) confer immunity against mobile genetic elements (MGEs) in prokaryotes. Streptococcus agalactiae, a leading cause of neonatal infections contains in its genome two CRISPR/Cas systems. We show that type 1-C CRISPR2 is present in few strains but type 2-A CRISPR1 is ubiquitous. Comparative sequence analysis of the CRISPR1 spacer content of 351 S. agalactiae strains revealed that it is extremely diverse due to the acquisition of new spacers, spacer duplications and spacer deletions that witness the dynamics of this system. The spacer content profile mirrors the S. agalactiae population structure. Transfer of a conjugative transposon targeted by CRISPR1 selected for spacer rearrangements, suggesting that deletions and duplications pre-exist in the population. The comparison of protospacers located within MGE or the core genome and protospacer-associated motif-shuffling demonstrated that the GG motif is sufficient to discriminate self and non-self and for spacer selection and integration. Strikingly more than 40% of the 949 different CRISPR1 spacers identified target MGEs found in S. agalactiae genomes. We thus propose that the S. agalactiae type II-A CRISPR1/Cas system modulates the cohabitation of the species with its mobilome, as such contributing to the diversity of MGEs in the population. © 2012 Blackwell Publishing Ltd.

  7. Streptococcus agalactiae Inhibits Candida albicans Hyphal Development and Diminishes Host Vaginal Mucosal TH17 Response

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Yu

    2018-02-01

    Full Text Available Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans, and that EFG1-Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC, the fungal burden and the levels of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae, while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1-Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans.

  8. Streptococcus agalactiae Inhibits Candida albicans Hyphal Development and Diminishes Host Vaginal Mucosal TH17 Response.

    Science.gov (United States)

    Yu, Xiao-Yu; Fu, Fei; Kong, Wen-Na; Xuan, Qian-Kun; Wen, Dong-Hua; Chen, Xiao-Qing; He, Yong-Ming; He, Li-Hua; Guo, Jian; Zhou, Ai-Ping; Xi, Yang-Hong; Ni, Li-Jun; Yao, Yu-Feng; Wu, Wen-Juan

    2018-01-01

    Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans , and that EFG1 -Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC), the fungal burden and the levels of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae , while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1 -Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans .

  9. Karakteristik dan Patogenisitas Streptococcus Agalactiae Tipe ?-hemolitik dan Non-hemolitik pada Ikan Nila

    Directory of Open Access Journals (Sweden)

    Esti Handayani Hardi

    2012-11-01

    Full Text Available Streptococcus agalactiae was isolated from cultured Nile tilapia (Oreochromis niloticus in Cirata gulfand Klaten. The isolates were Gram positive cocci, oxidative fermentative positive, motility, and catalasenegative, grown on media containing NaCl 6.5%, ?-haemolytic and non-haemolytic. Two types of S. agalactiae(?-haemolytic and non-haemolytic are different from their variety of sugars fermentation. Strains ?-haemolytic can ferment more sugars, including arabinose, sorbitol, lactose, and trehalose. Experimentalinfectivity trials on Nile tilapia (size 15 g, non-haemolytic type showed more virulent. This type causedfaster mortality, more severe behavior changes, and pathology changes than â-haemolytic type. NonhemoliticS. agalactiae caused 48% mortality 6-24 hours after injection, whereas â-haemolitic type caused17% mortality which it occured in 48 hours after injection (mortality of fish control 2,22%. Behaviordisease signs caused by non-haemolitic S. agalactiae started to happen 6 hours after injection whereas 12hours in ?-haemolytic type infection. Histopatological changes were observed on fish eye, spleen, andbrain. Hyperaemia, hyperthrophi, degeneration, and necrosis were also found on infected fish. Thisresearch was concluded that non-haemolytic of S. agalactiae was more virulent than ?-haemolytic.

  10. Annual incidence, prevalence and transmission characteristics of Streptococcus agalactiae in Danish dairy herds

    DEFF Research Database (Denmark)

    Mweu, Marshal M.; Nielsen, Søren S.; Hisham Beshara Halasa, Tariq

    2012-01-01

    -level incidence rates and apparent prevalences of Streptococcus agalactiae (S. agalactiae) in the population of Danish dairy cattle herds over a 10-year period from 2000 to 2009 inclusive and (2) to estimate the herd-level entry and exit rates (demographic parameters), the transmission parameter, β, and recovery...... rate for S. agalactiae infection. Data covering the specified period, on bacteriological culture of all bulk tank milk samples collected annually as part of the mandatory Danish S. agalactiae surveillance scheme, were extracted from the Danish Cattle Database and subsequently analysed....... There was an increasing trend in both the incidence and prevalence of S. agalactiae over the study period. Per 100 herd-years the value of β was 54.1 (95% confidence interval [CI] 46.0–63.7); entry rate 0.3 (95% CI 0.2–0.4); infection-related exit rate 7.1 (95% CI 5.6–8.9); non-infection related exit rate 9.2 (95% CI 7...

  11. Expression, purification, crystallization and preliminary crystallographic analysis of laminin-binding protein (Lmb) from Streptococcus agalactiae

    International Nuclear Information System (INIS)

    Ragunathan, Preethi; Spellerberg, Barbara; Ponnuraj, Karthe

    2009-01-01

    Laminin-binding protein from S. agalactiae was expressed, purified and crystallized and X-ray diffraction data were collected to 2.5 Å resolution. Laminin-binding protein (Lmb), a surface-exposed lipoprotein from Streptococcus agalactiae (group B streptococcus), mediates attachment to human laminin and plays a crucial role in the adhesion/invasion of eukaryotic host cells. However, the structural basis of laminin binding still remains unclear. In the context of detailed structural analysis, the lmb gene has been cloned, expressed in Escherichia coli, purified and crystallized. The crystals diffracted to a resolution of 2.5 Å and belonged to the monoclinic space group P2 1 , with unit-cell parameters a = 56.63, b = 70.60, c = 75.37 Å, β = 96.77°

  12. Diversity of prophage DNA regions of Streptococcus agalactiae clonal lineages from adults and neonates with invasive infectious disease.

    Directory of Open Access Journals (Sweden)

    Mazen Salloum

    Full Text Available The phylogenetic position and prophage DNA content of the genomes of 142 S. agalactiae (group-B streptococcus, GBS isolates responsible for bacteremia and meningitis in adults and neonates were studied and compared. The distribution of the invasive isolates between the various serotypes, sequence types (STs and clonal complexes (CCs differed significantly between adult and neonatal isolates. Use of the neighbor-net algorithm with the PHI test revealed evidence for recombination in the population studied (PHI, P = 2.01 × 10(-6, and the recombination-mutation ratio (R/M was 6:7. Nevertheless, the estimated R/M ratio differed between CCs. Analysis of the prophage DNA regions of the genomes of the isolates assigned 90% of the isolates to five major prophage DNA groups: A to E. The mean number of prophage DNA fragments amplified per isolate varied from 2.6 for the isolates of prophage DNA group E to 4.0 for the isolates of prophage DNA group C. The isolates from adults and neonates with invasive diseases were distributed differently between the various prophage DNA groups (P < 0.00001. Group C prophage DNA fragments were found in 52% of adult invasive isolates, whereas 74% of neonatal invasive isolates had prophage DNA fragments of groups A and B. Differences in prophage DNA content were also found between serotypes, STs and CCs (P < 0.00001. All the ST-1 and CC1 isolates, mostly of serotype V, belonged to the prophage DNA group C, whereas 84% of the ST-17 and CC17 isolates, all of serotype III, belonged to prophage DNA groups A and B. These data indicate that the transduction mechanisms, i.e., gene transfer from one bacterium to another by a bacteriophage, underlying genetic recombination in S. agalactiae species, are specific to each intraspecies lineage and population of strains responsible for invasive diseases in adults and neonates.

  13. Development of Primer Sets for Loop-Mediated Isothermal Amplification that Enables Rapid and Specific Detection of Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae

    Directory of Open Access Journals (Sweden)

    Deguo Wang

    2015-05-01

    Full Text Available Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae are the three main pathogens causing bovine mastitis, with great losses to the dairy industry. Rapid and specific loop-mediated isothermal amplification methods (LAMP for identification and differentiation of these three pathogens are not available. With the 16S rRNA gene and 16S-23S rRNA intergenic spacers as targets, four sets of LAMP primers were designed for identification and differentiation of S. dysgalactiae, S. uberis and S. agalactiae. The detection limit of all four LAMP primer sets were 0.1 pg DNA template per reaction, the LAMP method with 16S rRNA gene and 16S-23S rRNA intergenic spacers as the targets can differentiate the three pathogens, which is potentially useful in epidemiological studies.

  14. Development of Primer Sets for Loop-Mediated Isothermal Amplification that Enables Rapid and Specific Detection of Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae.

    Science.gov (United States)

    Wang, Deguo; Liu, Yanhong

    2015-05-26

    Streptococcus dysgalactiae, Streptococcus uberis and Streptococcus agalactiae are the three main pathogens causing bovine mastitis, with great losses to the dairy industry. Rapid and specific loop-mediated isothermal amplification methods (LAMP) for identification and differentiation of these three pathogens are not available. With the 16S rRNA gene and 16S-23S rRNA intergenic spacers as targets, four sets of LAMP primers were designed for identification and differentiation of S. dysgalactiae, S. uberis and S. agalactiae. The detection limit of all four LAMP primer sets were 0.1 pg DNA template per reaction, the LAMP method with 16S rRNA gene and 16S-23S rRNA intergenic spacers as the targets can differentiate the three pathogens, which is potentially useful in epidemiological studies.

  15. Evaluation of colorimetric loop-mediated isothermal amplification assay for visual detection of Streptococcus agalactiae and Streptococcus iniae in tilapia.

    Science.gov (United States)

    Suebsing, R; Kampeera, J; Tookdee, B; Withyachumnarnkul, B; Turner, W; Kiatpathomchai, W

    2013-10-01

    Streptococcus agalactiae and Strep. iniae are bacterial pathogens that cause streptococcosis in many fish species. An accelerated colorimetric loop-mediated isothermal amplification (LAMP) assay with pre-addition of calcein was established, and the transmission and detection of Strep. agalactiae and Strep. iniae in tilapia under natural aquatic environment were investigated. A positive reaction was observed by a colour change from orange to green through the naked eyes after completion at 63°C for 30 min with 10 times higher sensitivity than that of nested PCR assays and without cross-amplification with other fish bacterial pathogens. All sample types of Nile and red tilapia (broodstock, fertilized egg, fry) were Strep. agalactiae- and Strep. iniae positive by this new method, implying that they could be vertically transmitted. With its application for screening broodstock and fry before stocking and for monitoring fish health in grow-out ponds, the method would become very useful in fish farming industry. The application of colorimetric LAMP with pre-addition of calcein offers simple, rapid and sensitive technique with applicability for small field laboratories. This technique explored the possible vertical transmission mode of Strep. agalactiae and Strep. iniae under natural aquatic environment. It could be such preliminary data provided for the screening broodstock before breeding and/or the specific-pathogen-free production. © 2013 The Society for Applied Microbiology.

  16. Serotype markers in a Streptococcus agalactiae strain collection from Zimbabwe

    Directory of Open Access Journals (Sweden)

    Mavenyengwa R

    2010-01-01

    Full Text Available Objective: Group B streptococci (GBS from Southern African areas have been less well characterized. Our objective was to study serotype and serovariant distribution of carrier GBS strains as part of a study of the epidemiology of GBS carriage in pregnant women from Zimbabwe. Materials and Methods: We studied GBS isolated from 121 healthy pregnant women living in Harare and surrounding areas, Zimbabwe. Capsular polysaccharide (CPS testing for serotype determination and surface-anchored protein testing for serosubtype determination were done by gene-based serotyping (PCR, except for the proteins R3 and a novel protein called Z, which were detected by antibody-based methods. Results: Strains of the CPS types Ia (15.7%, Ib (11.6%, II (8.3%, III (38.8%, V (24.0% and NT (1.7% were detected along with the strain-variable proteins Cί (15.7% of isolates, Cα (19.8%, Alp1 (epsilon-22.3%, Alp3 (5.0%, R4/Rib (46.3%, R3 (27.3%, Z (27.3%, and SAR5 (28.9%, which encodes the R5 protein. Up to four of the protein genes could be possessed or the gene product expressed by one and the same isolate. A total of 32 serovariants were detected. The findings assessed by us as most important were the very low prevalence of the gene Alp3 (Alp3 - 4.9%, high prevalence of R4 (Rib - 46.2%, the proteins R3 (27.3%, Z (27.3%, and of SAR5 (R5 - 28.9%. The low prevalence of Alp3, notably in GBS type V strains, differed from findings with CPS type V GBS from non-African areas. Bacteria of the various CPS types showed distinct CPS/protein-marker associations. Conclusion: The results are of importance in relation to regional variations of GBS phenotypes and genotypes and thus, of importance in planning and research in the context of future vaccine formulations.

  17. Single nucleotide resolution RNA-seq uncovers new regulatory mechanisms in the opportunistic pathogen Streptococcus agalactiae.

    Science.gov (United States)

    Rosinski-Chupin, Isabelle; Sauvage, Elisabeth; Sismeiro, Odile; Villain, Adrien; Da Cunha, Violette; Caliot, Marie-Elise; Dillies, Marie-Agnès; Trieu-Cuot, Patrick; Bouloc, Philippe; Lartigue, Marie-Frédérique; Glaser, Philippe

    2015-05-30

    Streptococcus agalactiae, or Group B Streptococcus, is a leading cause of neonatal infections and an increasing cause of infections in adults with underlying diseases. In an effort to reconstruct the transcriptional networks involved in S. agalactiae physiology and pathogenesis, we performed an extensive and robust characterization of its transcriptome through a combination of differential RNA-sequencing in eight different growth conditions or genetic backgrounds and strand-specific RNA-sequencing. Our study identified 1,210 transcription start sites (TSSs) and 655 transcript ends as well as 39 riboswitches and cis-regulatory regions, 39 cis-antisense non-coding RNAs and 47 small RNAs potentially acting in trans. Among these putative regulatory RNAs, ten were differentially expressed in response to an acid stress and two riboswitches sensed directly or indirectly the pH modification. Strikingly, 15% of the TSSs identified were associated with the incorporation of pseudo-templated nucleotides, showing that reiterative transcription is a pervasive process in S. agalactiae. In particular, 40% of the TSSs upstream genes involved in nucleotide metabolism show reiterative transcription potentially regulating gene expression, as exemplified for pyrG and thyA encoding the CTP synthase and the thymidylate synthase respectively. This comprehensive map of the transcriptome at the single nucleotide resolution led to the discovery of new regulatory mechanisms in S. agalactiae. It also provides the basis for in depth analyses of transcriptional networks in S. agalactiae and of the regulatory role of reiterative transcription following variations of intra-cellular nucleotide pools.

  18. Discovery and Characterization of Human-Urine Utilization by Asymptomatic-Bacteriuria-Causing Streptococcus agalactiae.

    Science.gov (United States)

    Ipe, Deepak S; Ben Zakour, Nouri L; Sullivan, Matthew J; Beatson, Scott A; Ulett, Kimberly B; Benjamin, William H; Davies, Mark R; Dando, Samantha J; King, Nathan P; Cripps, Allan W; Schembri, Mark A; Dougan, Gordon; Ulett, Glen C

    2016-01-01

    Streptococcus agalactiae causes both symptomatic cystitis and asymptomatic bacteriuria (ABU); however, growth characteristics of S. agalactiae in human urine have not previously been reported. Here, we describe a phenotype of robust growth in human urine observed in ABU-causing S. agalactiae (ABSA) that was not seen among uropathogenic S. agalactiae (UPSA) strains isolated from patients with acute cystitis. In direct competition assays using pooled human urine inoculated with equal numbers of a prototype ABSA strain, designated ABSA 1014, and any one of several UPSA strains, measurement of the percentage of each strain recovered over time showed a markedly superior fitness of ABSA 1014 for urine growth. Comparative phenotype profiling of ABSA 1014 and UPSA strain 807, isolated from a patient with acute cystitis, using metabolic arrays of >2,500 substrates and conditions revealed unique and specific l-malic acid catabolism in ABSA 1014 that was absent in UPSA 807. Whole-genome sequencing also revealed divergence in malic enzyme-encoding genes between the strains predicted to impact the activity of the malate metabolic pathway. Comparative growth assays in urine comparing wild-type ABSA and gene-deficient mutants that were functionally inactivated for the malic enzyme metabolic pathway by targeted disruption of the maeE or maeK gene in ABSA demonstrated attenuated growth of the mutants in normal human urine as well as synthetic human urine containing malic acid. We conclude that some S. agalactiae strains can grow in human urine, and this relates in part to malic acid metabolism, which may affect the persistence or progression of S. agalactiae ABU. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  19. Development of live attenuated Streptococcus agalactiae vaccine for tilapia via continuous passage in vitro.

    Science.gov (United States)

    Li, L P; Wang, R; Liang, W W; Huang, T; Huang, Y; Luo, F G; Lei, A Y; Chen, M; Gan, X

    2015-08-01

    Fish Streptococcus agalactiae (S. agalactiae) seriously harms the world's aquaculture industry and causes huge economic losses. This study aimed to develop a potential live attenuated vaccine of S. agalactiae. Pre-screened vaccine candidate strain S. agalactiae HN016 was used as starting material to generate an attenuated strain S. agalactiae YM001 by continuous passage in vitro. The biological characteristics, virulence, and stability of YM001 were detected, and the protective efficacy of YM001 immunization in tilapia was also determined. Our results indicated that the growth, staining, characteristics of pulsed-field gel electrophoresis (PFGE) genotype, and virulence of YM001 were changed significantly as compared to the parental strain HN016. High doses of YM001 by intraperitoneal (IP) injection (1.0 × 10(9) CFU/fish) and oral gavage (1.0 × 10(10) CFU/fish) respectively did not cause any mortality and morbidity in tilapia. The relative percent survivals (RPSs) of fishes immunized with YM001 (1.0 × 10(8) CFU/fish, one time) via injection, immersion, and oral administration were 96.88, 67.22, and 71.81%, respectively, at 15 days, and 93.61, 60.56, and 53.16%, respectively, at 30 days. In all tests with 1-3 times of immunization in tilapia, the dosages at 1 × 10(8) and 1 × 10(9) CFU/fish displayed the similar best results, whereas the immunoprotection of the dosages at 1 × 10(6) and 1 × 10(7) CFU/fish declined significantly (P 0.05). The level of protective antibody elicited by oral immunization was significantly higher compared to that of the control group (P S. agalactiae strain YM001; oral immunization of tilapia with this strain produced a good immune protection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. GapA, a potential vaccine candidate antigen against Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Zhang, Ze; Yu, Angen; Lan, Jiangfeng; Zhang, Hua; Hu, Minqiang; Cheng, Jiewei; Zhao, Lijuan; Lin, Li; Wei, Shun

    2017-04-01

    Streptococcosis due to the bacterium Streptococcus agalactiae (S. agalactiae) has resulted in enormous economic losses in aquaculture worldwide, especially in the tilapia culture industry. Previously, there were limited vaccines that could be employed against streptococcosis in tilapia. This study aimed to develop a vaccine candidate using the glyceraldehyde-phosphate dehydrogenase protein (GapA) of S. agalactiae encoded by the gapA gene. Tilapia were intraperitoneally injected with PBS, PBS + Freund's adjuvant, PBS + Montanide's adjuvant, GapA + Freund's adjuvant, GapA + Montanide's adjuvant, killed S. agalactiae whole cells (WC)+Freund's adjuvant, or killed S. agalactiae whole cells (WC)+ Montanide's adjuvant. They were then challenged with S. agalactiae, and the relative percentage survival (RPS) was monitored 14 days after the challenge. The highest RPSs were observed in the WC groups, with 76.7% in WC + Freund's adjuvant and 74.4% in WC + Montanide's adjuvant groups; these were followed by the GapA groups, with 63.3% in GapA + Freund's adjuvant and 45.6% in GapA + Montanide's adjuvant groups. The RPS of the PBS group was 0%, and those of PBS + Freund's adjuvant and PBS + Montanide's adjuvant groups were 6.7% and 3.3%, respectively. Additionally, the IgM antibody responses elicited in GapA groups and WC groups were significantly higher than those in PBS groups. Furthermore, the expressions of cytokine (IL-1β and TNF-α) mRNAs in the GapA groups and WC groups were significantly higher than those in the PBS groups. Taken together, these results reveal that the GapA protein is a promising vaccine candidate that could be used to prevent streptococcosis in tilapia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Streptococcus agalactiae in the environment of bovine dairy herds--rewriting the textbooks?

    Science.gov (United States)

    Jørgensen, H J; Nordstoga, A B; Sviland, S; Zadoks, R N; Sølverød, L; Kvitle, B; Mørk, T

    2016-02-29

    Many free-stall bovine dairy herds in Norway fail to eradicate Streptococcus agalactiae despite long-term control measures. In a longitudinal study of 4 free-stall herds with automatic milking systems (AMS), milk and extramammary sites were sampled 4 times with 1-2 month intervals. Composite milk, rectal- and vaginal swabs were collected from dairy cows; rectal swabs from heifers and young stock; rectal- and tonsillar swabs from calves; and environmental swabs from the AMS, the floors, cow beds, watering and feeding equipment. A cross sectional study of 37 herds was also conducted, with 1 visit for environmental sampling. Fifteen of the herds were known to be infected with S. agalactiae while the remaining 22 had not had evidence of S. agalactiae mastitis in the preceding 2 years. All samples were cultured for S. agalactiae, and selected isolates (n=54) from positive herds were genotyped by Multi Locus Sequence Typing (MLST). Results show that the bovine gastrointestinal tract and the dairy cow environment are reservoirs of S. agalactiae, and point to the existence of 2 transmission cycles; a contagious transmission cycle via the milking machine and an oro-fecal transmission cycle, with drinking water as the most likely vehicle for transmission. Ten sequence types were identified, and results suggest that strains differ in their ability to survive in the environment and transmit within dairy herds. Measures to eradicate S. agalactiae from bovine dairy herds should take into account the extra-mammary reservoirs and the potential for environmental transmission of this supposedly exclusively contagious pathogen. Copyright © 2016. Published by Elsevier B.V.

  2. The protective duration of Streptococcus agalactiae vaccine in Nile Tilapia for the prevention of streptococcosis

    Directory of Open Access Journals (Sweden)

    , Sukenda

    2016-02-01

    Full Text Available ABSTRACT The aim of this study was to assess the protective duration of Streptococcus agalactiae vaccine against streptococcosis in Nile tilapia. Fish were treated by the whole cell vaccine, ECP vaccine and mixture of whole cell and ECP vaccine. After 14, 28, 42, and 52 day post-vaccination (DPV, the fish were intraperitoneally challenged with 104  cfu/mL S. agalactiae. The results showed mortality rate of whole-cell vaccine (A, ECP vaccine (B and mix vaccine (C up to day 42 was significantly (P<0.05 lower than the control treatment, namely 73.33%; 80%; and 76%, respectively. The mortality rate of vaccine treatments A, B, and C on day 56 had no significant difference (P>0.05 with the control. The value of antibody titer vaccine treatments A, B, and C indicate that antigen-antibody reaction on day 28 after the vaccination was significantly (P <0.05 higher than the control that were 3.67; 3.33; and 3.67. Antigen-antibody reaction on day 42 after the vaccination was founded, but did not different significantly (P>0.05 with the control. Bacterial population in treatment A, B, and C in the organs of the fish until the 28th day was still under the control of 104  cfu/mL. S. agalactiae vaccine protection duration is 42 days after the vaccination. Keywords : nile tilapia, Streptococcus agalactiae, duration, vaccine, streptococcosis  ABSTRAK Penelitian ini bertujuan untuk menganalisis durasi proteksi dari vaksin Streptococcus agalactiae sebagai pencegahan terhadap streptococcosis pada ikan nila. Ikan divaksinasi dengan vaksin sel utuh, ECP dan gabungan sel utuh dan ECP dari S. agalactiae yang diinjeksi secara intrapetorineal. Ikan diuji tantang S. agalactiae 104  cfu/mL pada hari ke-14, ke-28, ke-42, dan ke-56 pascavaksinasi. Hasil penelitian menunjukkan tingkat mortalitas perlakuan vaksin sel utuh (A, vaksin ECP (B, dan gabungan vaksin sel utuh dengan ECP (C hingga hari ke-42 masih signifikan (P<0,05 lebih rendah dari perlakuan kontrol yaitu 73

  3. Molecular characterization of Streptococcus agalactiae strains isolated from fishes in Malaysia.

    Science.gov (United States)

    Amal, M N A; Zamri-Saad, M; Siti-Zahrah, A; Zulkafli, A R; Nur-Nazifah, M

    2013-07-01

    The aim of this study was to characterize Streptococcus agalactiae strains that were isolated from fishes in Malaysia using random amplified polymorphic DNA (RAPD) and repetitive extragenic palindromic PCR (REP-PCR) techniques. A total of 181 strains of Strep. agalactiae isolated from red hybrid tilapia (Oreochromis sp.) and golden pompano (Trachinotus blochii) were characterized using RAPD and REP-PCR techniques. Both the fingerprinting techniques generated reproducible band patterns, differing in the number and molecular mass amplicons. The RAPD technique displayed greater discriminatory power by its production of more complex binding pattern and divided all the strains into 13 groups, compared to 9 by REP-PCR technique. Both techniques showed the availability to differentiate the genetic profiles of the strains according to their geographical location of origin. Three strains of Strep. agalactiae that were recovered from golden pompano showed a genetic dissimilarity from the strains isolated from red hybrid tilapia, while the strain of ATCC 27956 that recovered from bovine displayed a unique profile for both methods. Both techniques possess excellent discriminative capabilities and can be used as a rapid means of comparing Strep. agalactiae strains for future epidemiological investigation. Framework as the guideline in traceability of this disease and in the search for potential local vaccine candidates for streptococcosis in this country. Journal of Applied Microbiology © 2013 The Society for Applied Microbiology.

  4. Amperometric biosensor based on a single antibody of dual function for rapid detection of Streptococcus agalactiae.

    Science.gov (United States)

    Vásquez, Gersson; Rey, Alba; Rivera, Camilo; Iregui, Carlos; Orozco, Jahir

    2017-01-15

    Pathogenic bacteria are responsible for several diseases in humans and in a variety of hosts. Detection of pathogenic bacteria is imperative to avoid and/or fight their potential harmful effects. This work reports on the first amperometric biosensor for the rapid detection of Streptococcus agalactiae (S. agalactiae). The biosensor relies on a single biotinylated antibody that immobilizes the bacteria on a screen-printed carbon electrode while is further linked to a streptavidin-conjugated HRP reporter. The biotinylated antibody provides selectivity to the biosensor whereas serves as an anchoring point to the reporter for further amplification of the electrochemical signal. The resultant immunosensor is simple, responds rapidly, and allows for the selective and highly sensitive quantification of S. agalactiae cells in a concentration range of 10 1 -10 7 CFUml -1 , with a detection limit of 10CFUml -1 . The approach not only enables a rapid detection and quantification of S. agalactiae in environmental samples but also opens up new opportunities for the simple fabrication of electrochemical immunosensors for different target pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Physiological impact of transposable elements encoding DDE transposases in the environmental adaptation of Streptococcus agalactiae.

    Science.gov (United States)

    Fléchard, Maud; Gilot, Philippe

    2014-07-01

    We have referenced and described Streptococcus agalactiae transposable elements encoding DDE transposases. These elements belonged to nine families of insertion sequences (ISs) and to a family of conjugative transposons (TnGBSs). An overview of the physiological impact of the insertion of all these elements is provided. DDE-transposable elements affect S. agalactiae in a number of aspects of its capability to adapt to various environments and modulate the expression of several virulence genes, the scpB-lmB genomic region and the genes involved in capsule expression and haemolysin transport being the targets of several different mobile elements. The referenced mobile elements modify S. agalactiae behaviour by transferring new gene(s) to its genome, by modifying the expression of neighbouring genes at the integration site or by promoting genomic rearrangements. Transposition of some of these elements occurs in vivo, suggesting that by dynamically regulating some adaptation and/or virulence genes, they improve the ability of S. agalactiae to reach different niches within its host and ensure the 'success' of the infectious process. © 2014 The Authors.

  6. Comparison of virulence factors and capsular types of Streptococcus agalactiae isolated from human and bovine infections.

    Science.gov (United States)

    Emaneini, Mohammad; Khoramian, Babak; Jabalameli, Fereshteh; Abani, Samira; Dabiri, Hossein; Beigverdi, Reza

    2016-02-01

    Streptococcus agalactiae is a leading cause of human and bovine infections. A total of 194 S. agalactiae isolates, 55 isolates from bovines and 139 from humans, were analyzed for capsular types, virulence genes (scpB, hly, rib, bca and bac) and mobile genetic elements (IS1548 and GBSi1) using polymerase chain reaction (PCR) and multiplex PCR. Capsular type III was predominant (61%), followed by types V, II, Ib, and IV. The scpB, hly, bca and bac virulence genes were only found among human isolates. Twelve and 2 distinct virulence gene profiles were identified among human and bovine isolates respectively. The virulence gene profiles scpB- hly- IS1548- rib-bca (51%) and scpB- hly- IS1548- bca (19%) were only predominant among human isolates. The rib gene was the most common virulence gene in both human and bovine isolates. The study showed a high prevalence of virulence genes in S. agalactiae strains isolated from human infections, these result can support the idea that S. agalactiae isolated from humans and bovines are generally unrelated and probably belonged to separate populations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. A case of infective endocarditis along with a ruptured valve caused by Streptococcus agalactiae in an immunocompetent man.

    Science.gov (United States)

    Suzuki, Kiyozumi; Hirai, Yuji; Morita, Fujiko; Uehara, Yuki; Oshima, Hiroko; Mitsuhashi, Kazunori; Amano, Atsushi; Naito, Toshio

    2016-01-01

    Streptococcus agalactiae ( S. agalactiae ) is a major cause of invasive disease in neonates and pregnant women, but has also recently been observed among non-pregnant adults, especially elderly persons or persons with underlying chronic disease. S. agalactiae is also a rare cause of infective endocarditis, and most cases require early surgery. We report the case of a 43-year-old previously healthy man who experienced rapid progressive culture-negative infective endocarditis with aortic valve vegetation and severe aortic regurgitation, which was complicated by lumbar spondylodiscitis. Emergency aortic valve replacement was performed on the day of his admission, which revealed a congenital bicuspid aortic valve was ruptured by the vegetation. The resected aortic valve specimen was submitted for 16S ribosomal RNA gene sequencing, which revealed that the pathogen was S. agalactiae . Therefore, S. agalactiae should be considered a potentially causative pathogen in cases of rapid progressive infective endocarditis, even if it occurs in a non-pregnant immunocompetent adult.

  8. Natural coinfection by Streptococcus agalactiae and Francisella noatunensis subsp. orientalis in farmed Nile tilapia (Oreochromis niloticus L.).

    Science.gov (United States)

    Assis, G B N; Tavares, G C; Pereira, F L; Figueiredo, H C P; Leal, C A G

    2017-01-01

    Streptococcus agalactiae and Francisella noatunensis subsp. orientalis (Fno) are important pathogens for farm-raised tilapia worldwide. There are no reports of coinfection caused by S. agalactiae and Fno in fish. This study aimed to determine the aetiology of atypical mortalities in a cage farm of Nile tilapia and to characterize the genetic diversity of the isolates. Fifty-two fish were sampled and subjected to parasitological and bacteriological examination. The S. agalactiae and Fno isolates were genotyped using MLST and REP-PCR, respectively. Whole-genome sequencing was performed to confirm the MLST results. Seven fish were shown coinfected by S. agalactiae and Fno. Chronic hypoxia and a reduction in the water temperature were determined as risk factors for coinfection. Fno isolates were shown clonally related in REP-PCR. The MLST analysis revealed that the S. agalactiae isolates from seven coinfected fish were negative for the glcK gene; however, these were determined to be members of clonal complex CC-552. This is the first description of coinfection by S. agalactiae and Fno in farm-raised Nile tilapia. The coinfection was predisposed by chronic hypoxia and was caused by the main genotypes of S. agalactiae and Fno reported in Brazil. Finally, a new S. agalactiae genotype with glcK gene partially deleted was described. © 2016 John Wiley & Sons Ltd.

  9. Prophagic DNA Fragments in Streptococcus agalactiae Strains and Association with Neonatal Meningitis

    Science.gov (United States)

    van der Mee-Marquet, Nathalie; Domelier, Anne-Sophie; Mereghetti, Laurent; Lanotte, Philippe; Rosenau, Agnès; van Leeuwen, Willem; Quentin, Roland

    2006-01-01

    We identified—by randomly amplified polymorphic DNA (RAPD) analysis at the population level followed by DNA differential display, cloning, and sequencing—three prophage DNA fragments (F5, F7, and F10) in Streptococcus agalactiae that displayed significant sequence similarity to the DNA of S. agalactiae and Streptococcus pyogenes. The F5 sequence aligned with a prophagic gene encoding the large subunit of a terminase, F7 aligned with a phage-associated cell wall hydrolase and a phage-associated lysin, and F10 aligned with a transcriptional regulator (ArpU family) and a phage-associated endonuclease. We first determined the prevalence of F5, F7, and F10 by PCR in a collection of 109 strains isolated in the 1980s and divided into two populations: one with a high risk of causing meningitis (HR group) and the other with a lower risk of causing meningitis (LR group). These fragments were significantly more prevalent in the HR group than in the LR group (P S. agalactiae strains to invade the neonatal brain endothelium. We then determined the prevalence of F5, F7, and F10 by PCR in a collection of 40 strains recently isolated from neonatal meningitis cases for comparison with the cerebrospinal fluid (CSF) strains isolated in the 1980s. The prevalence of the three prophage DNA fragments was similar in these two populations isolated 15 years apart. We suggest that the prophage DNA fragments identified have remained stable in many CSF S. agalactiae strains, possibly due to their importance in virulence or fitness. PMID:16517893

  10. [Effect of the 10 kb sequence of piscine Streptococcus agalactiae on bacterial virulence].

    Science.gov (United States)

    Liu, Guangjin; Zhu, Jielian; Shi, Ziwei; Ding, Ming; Wang, Ruyi; Yao, Huochun; Lu, Chengping; Xu, Pao

    2016-01-04

    From the previous comparative genomic analysis, we found a specific unknown 10 kb sequence (including 11 Open reading Frames) in Chinese piscine strain GD201008-001 genome. To study the role of 10 kb in the pathogenicity of piscine S. agalactiae, the 10 kb sequence was deleted from the GD201008-001 genome. The isogenic mutant Δ10 kb was constructed by using the temperature-sensitive Streptococcus-E. coli shuttle vector pSET4s. We compared the growth characteristics, adherence to HEp-2 cell and bacterial virulence in a zebrafish infection model between wild strain and mutant. Meanwhile the expressions of the known virulence genes from GD201008-001 and Δ10 kb were also quantified by real-time PCR. The Δ10 kb showed no significant differences in bacterial morphology and adherence to HEp-2 cells compared with the wild-type strain, but the speed of growth was slightly slower than the wild strain. Furthermore the 50% lethal dose of Δ10 kb was decreased up to 10-fold (P kb sequence of piscine Streptococcus agalactiae exerts a significant effect on bacterial virulence and probably regulates the virulence genes expression of GD20 1008-001.

  11. Fulminant Necrotizing Fasciitis and Toxic Shock Syndrome Caused by Streptococcus agalactiae

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    Emin UYSAL

    2018-03-01

    Full Text Available Necrotizing fasciitis is a rare and life-threatening soft tissue infection that spreads rapidly and involves the skin, subcutaneous tissue, fascia, and muscle layer. The treatment is possible by initiating appropriate antibiotherapy for the clinically suspected cause and by performing surgical intervention quickly and aggressively. However, it should be known that necrotizing fasciitis is a disease that is difficult to manage despite all interventions, effective treatment protocols, and patient care. This article presents the case of a 60-year-old patient with diabetes mellitus who died of toxic shock syndrome with fulminant necrotizing fasciitis caused by Streptococcus agalactiae.

  12. Streptococcus agalactiae: HASTA AHORA EL ÚNICO Streptococcus PATÓGENO DE TILAPIAS CULTIVADAS EN COLOMBIA

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    AP Jiménez

    2007-01-01

    Full Text Available Las estreptococosis son un conjunto de enfermedades ocasionadas por un grupo de cocos Gram positivos con similares signologías que involucran distintos órganos en los individuos afectados. La identiÀcación precisa de cada uno de estos microorganismos no se logra de manera deÀnitiva por los métodos tradicionales microbiológicos, por lo que se debe acudir a otro tipo de metodologías como las técnicas de biología molecular. En 1999 se identiÀcó por primera vez en Colombia la estreptococosis en híbridos de tilapias de cultivo. La pos-terior secuenciación del ADN de distintos aislamientos obtenidos de varias regiones del país demostró un 98,8% de aÀnidad con el Streptococcus agalactiae. El presente estudio pretende deÀnir si hasta la fecha existe solo esta especie de Streptococcus en el país causan-do infección o enfermedad en tilapias de cultivo o, por el contrario, son varias las especies que intervienen en los cuadros infecciosos. Se evaluaron aislamientos de tejidos, de agua y fango de los sitios de cultivo, así como de lugares de expendio de tilapia roja (Oreochromissp., utilizando técnicas microbiológicas, inmunoperoxidasa indirecta (IPI y PCR, espe-cíÀcas para el aislamiento e identiÀcación del S. agalactiae. Los resultados del presente estudio demostraron que hasta la fecha en el país únicamente se ha identiÀcado la especie S. agalactiae causando infección o enfermedad en tilapias. No tenemos evidencia de que otros Streptococcus reportados internacionalmente como S. iniae y otros Gram positivos causen estreptococosis en Colombia.La tilapia parece ser el principal reservorio del S. agalactiae en el país, y el riesgo zoonótico, aunque existe, es mínimo si se toman las medidas apropia-das de bioseguridad.

  13. Genomic comparison of virulent and non-virulent Streptococcus agalactiae in fish.

    Science.gov (United States)

    Delannoy, C M J; Zadoks, R N; Crumlish, M; Rodgers, D; Lainson, F A; Ferguson, H W; Turnbull, J; Fontaine, M C

    2016-01-01

    Streptococcus agalactiae infections in fish are predominantly caused by beta-haemolytic strains of clonal complex (CC) 7, notably its namesake sequence type (ST) 7, or by non-haemolytic strains of CC552, including the globally distributed ST260. In contrast, CC23, including its namesake ST23, has been associated with a wide homeothermic and poikilothermic host range, but never with fish. The aim of this study was to determine whether ST23 is virulent in fish and to identify genomic markers of fish adaptation of S. agalactiae. Intraperitoneal challenge of Nile tilapia, Oreochromis niloticus (Linnaeus), showed that ST260 is lethal at doses down to 10(2) cfu per fish, whereas ST23 does not cause disease at 10(7) cfu per fish. Comparison of the genome sequence of ST260 and ST23 with those of strains derived from fish, cattle and humans revealed the presence of genomic elements that are unique to subpopulations of S. agalactiae that have the ability to infect fish (CC7 and CC552). These loci occurred in clusters exhibiting typical signatures of mobile genetic elements. PCR-based screening of a collection of isolates from multiple host species confirmed the association of selected genes with fish-derived strains. Several fish-associated genes encode proteins that potentially provide fitness in the aquatic environment. © 2014 John Wiley & Sons Ltd.

  14. Orientation of streptococcus agalactiae irradiation dose for subclinical mastitis vaccine in dairy cows

    International Nuclear Information System (INIS)

    Tuasikal, B.J.; Estuningsih, S.; Pasaribu, F.H.; Wibawan, I.W.T.

    2012-01-01

    An experiment to determine the effect of gamma-ray irradiation in debilitating Streptococcus agalactiae as a cause of subclinical mastitis (inflammation of the udder) in cows has been conducted. S. agalactiae bacteria was isolated from subclinical mastitis found in dairy cows in the field was then observed for its cell growth. The bacteria which have reached mid-log phase of growth, were divided into 5 treatment groups, of which each was irradiated at dose level of 0; 25; 50; 75; and 100Gy. Irradiated bacteria subsequently were grown on Brain Heart Infusion agar (BHI), and each of its colonies was counted for LD50 determination. The obtained curves from irradiated treatment bacterial shown viability percentage by the linier equation of Y = 95.414 e -0,0371X ; R 2 = 0.9979, while Y = % viability and X = dose of irradiation. The calculation done in this experiment shows that irradiation dose of 17.4 Gy weaken the bacteria pathogenicity of S. agalactiae to the level of LD 50 . (author)

  15. The genetic diversity and phenotypic characterisation of Streptococcus agalactiae isolates from Rio de Janeiro, Brazil

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    Ana Beatriz de Almeida Corrêa

    2011-12-01

    Full Text Available Streptococcus agalactiae isolates are more common among pregnant women, neonates and nonpregnant adults with underlying diseases compared to other demographic groups. In this study, we evaluate the genetic and phenotypic diversity in S. agalactiae strains from Rio de Janeiro (RJ that were isolated from asymptomatic carriers. We analysed these S. agalactiae strains using pulsed-field gel electrophoresis (PFGE, serotyping and antimicrobial susceptibility testing, as well as by determining the macrolide resistance phenotype, and detecting the presence of the ermA/B, mefA/E and lnuB genes. The serotypes Ia, II, III and V were the most prevalent serotypes observed. The 60 strains analysed were susceptible to penicillin, vancomycin and levofloxacin. Resistance to clindamycin, chloramphenicol, erythromycin, rifampin and tetracycline was observed. Among the erythromycin and/or clindamycin resistant strains, the ermA, ermB and mefA/E genes were detected and the constitutive macrolides, lincosamides and streptogramin B-type resistance was the most prevalent phenotype observed. The lnuB gene was not detected in any of the strains studied. We found 56 PFGE electrophoretic profiles and only 22 of them were allocated in polymorphism patterns. This work presents data on the genetic diversity and prevalent capsular serotypes among RJ isolates. Approximately 85% of these strains came from pregnant women; therefore, these data may be helpful in developing future prophylaxis and treatment strategies for neonatal syndromes in RJ.

  16. Identification of genes preferentially expressed by highly virulent piscine Streptococcus agalactiae upon interaction with macrophages.

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    Chang-Ming Guo

    Full Text Available Streptococcus agalactiae, long recognized as a mammalian pathogen, is an emerging concern with regard to fish. In this study, we used a mouse model and in vitro cell infection to evaluate the pathogenetic characteristics of S. agalactiae GD201008-001, isolated from tilapia in China. This bacterium was found to be highly virulent and capable of inducing brain damage by migrating into the brain by crossing the blood-brain barrier (BBB. The phagocytosis assays indicated that this bacterium could be internalized by murine macrophages and survive intracellularly for more than 24 h, inducing injury to macrophages. Further, selective capture of transcribed sequences (SCOTS was used to investigate microbial gene expression associated with intracellular survival. This positive cDNA selection technique identified 60 distinct genes that could be characterized into 6 functional categories. More than 50% of the differentially expressed genes were involved in metabolic adaptation. Some genes have previously been described as associated with virulence in other bacteria, and four showed no significant similarities to any other previously described genes. This study constitutes the first step in further gene expression analyses that will lead to a better understanding of the molecular mechanisms used by S. agalactiae to survive in macrophages and to cross the BBB.

  17. KERENTANAN IKAN NILA SULTANA, RED NIFI, SRIKANDI DAN AUREUS TERHADAP INFEKSI BAKTERI Streptococcus agalactiae

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    Rita Febrianti

    2015-06-01

    Full Text Available Penelitian ini bertujuan untuk menguji kerentanan empat strain ikan nila, yaitu: Sultana, Red NIFI, Srikandi, dan Aureus terhadap infeksi bakteri Streptococcus agalactiae. Ikan uji berukuran 15-20 g/ekor dan berasal dari populasi, serta batch umur yang sama. Infeksi bakteri S. agalactiae dilakukan secara buatan melalui penyuntikan intra peritoneal (IP pada dosis 104 cfu/mL, sedangkan kelompok kontrol diinjeksi dengan larutan Phosphate Buffered Saline (PBS. Pengamatan dilakukan terhadap gejala klinis dan mortalitas ikan uji yang berlangsung selama 14 hari. Hasil penelitian menunjukkan bahwa seluruh strain ikan nila mengalami respons yang sama terhadap infeksi bakteri S. agalactie yang ditandai dengan munculnya gejala klinis seperti: warna gelap/menghitam, sirip geripis, nekrosa pada mulut, mata menonjol, opaque, ulcer, dan dropsy. Kerentanan tertinggi terhadap infeksi bakteri S. agalactiae yang dimanifestasikan dengan rataan persentase mortalitas ikan uji diperoleh pada ikan nila Aureus sebesar 72%, Sultana 50%, Srikandi 36%, Red NIFI sebesar 24%, dan kontrol tidak ada mortalitas. Setelah diuji tantang, kadar limfosit mengalami kenaikan, netrofil dan monosit mengalami penurunan.

  18. Identification of Genes Preferentially Expressed by Highly Virulent Piscine Streptococcus agalactiae upon Interaction with Macrophages

    Science.gov (United States)

    Guo, Chang-Ming; Chen, Rong-Rong; Kalhoro, Dildar Hussain; Wang, Zhao-Fei; Liu, Guang-Jin; Lu, Cheng-Ping; Liu, Yong-Jie

    2014-01-01

    Streptococcus agalactiae, long recognized as a mammalian pathogen, is an emerging concern with regard to fish. In this study, we used a mouse model and in vitro cell infection to evaluate the pathogenetic characteristics of S. agalactiae GD201008-001, isolated from tilapia in China. This bacterium was found to be highly virulent and capable of inducing brain damage by migrating into the brain by crossing the blood–brain barrier (BBB). The phagocytosis assays indicated that this bacterium could be internalized by murine macrophages and survive intracellularly for more than 24 h, inducing injury to macrophages. Further, selective capture of transcribed sequences (SCOTS) was used to investigate microbial gene expression associated with intracellular survival. This positive cDNA selection technique identified 60 distinct genes that could be characterized into 6 functional categories. More than 50% of the differentially expressed genes were involved in metabolic adaptation. Some genes have previously been described as associated with virulence in other bacteria, and four showed no significant similarities to any other previously described genes. This study constitutes the first step in further gene expression analyses that will lead to a better understanding of the molecular mechanisms used by S. agalactiae to survive in macrophages and to cross the BBB. PMID:24498419

  19. A multi locus variable number of tandem repeat analysis (MLVA scheme for Streptococcus agalactiae genotyping

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    Mereghetti Laurent

    2011-07-01

    Full Text Available Abstract Background Multilocus sequence typing (MLST is currently the reference method for genotyping Streptococcus agalactiae strains, the leading cause of infectious disease in newborns and a major cause of disease in immunocompromised children and adults. We describe here a genotyping method based on multiple locus variable number of tandem repeat (VNTR analysis (MLVA applied to a population of S. agalactiae strains of various origins characterized by MLST and serotyping. Results We studied a collection of 186 strains isolated from humans and cattle and three reference strains (A909, NEM316 and 2603 V/R. Among 34 VNTRs, 6 polymorphic VNTRs loci were selected for use in genotyping of the bacterial population. The MLVA profile consists of a series of allele numbers, corresponding to the number of repeats at each VNTR locus. 98 MLVA genotypes were obtained compared to 51 sequences types generated by MLST. The MLVA scheme generated clusters which corresponded well to the main clonal complexes obtained by MLST. However it provided a higher discriminatory power. The diversity index obtained with MLVA was 0.960 compared to 0.881 with MLST for this population of strains. Conclusions The MLVA scheme proposed here is a rapid, cheap and easy genotyping method generating results suitable for exchange and comparison between different laboratories and for the epidemiologic surveillance of S. agalactiae and analyses of outbreaks.

  20. Molecular identification and histopathological study of natural Streptococcus agalactiae infection in hybrid tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Laith, A A; Ambak, Mohd Azmi; Hassan, Marina; Sheriff, Shahreza Md; Nadirah, Musa; Draman, Ahmad Shuhaimi; Wahab, Wahidah; Ibrahim, Wan Nurhafizah Wan; Aznan, Alia Syafiqah; Jabar, Amina; Najiah, Musa

    2017-01-01

    The main objective of this study was to emphasize on histopathological examinations and molecular identification of Streptococcus agalactiae isolated from natural infections in hybrid tilapia ( Oreochromis niloticus ) in Temerloh Pahang, Malaysia, as well as to determine the susceptibility of the pathogen strains to various currently available antimicrobial agents. The diseased fishes were observed for variable clinical signs including fin hemorrhages, alterations in behavior associated with erratic swimming, exophthalmia, and mortality. Tissue samples from the eyes, brain, kidney, liver, and spleen were taken for bacterial isolation. Identification of S. agalactiae was screened by biochemical methods and confirmed by VITEK 2 and 16S rRNA gene sequencing. The antibiogram profiling of the isolate was tested against 18 standard antibiotics included nitrofurantoin, flumequine, florfenicol, amoxylin, doxycycline, oleandomycin, tetracycline, ampicillin, lincomycin, colistin sulfate, oxolinic acid, novobiocin, spiramycin, erythromycin, fosfomycin, neomycin, gentamycin, and polymyxin B. The histopathological analysis of eyes, brain, liver, kidney, and spleen was observed for abnormalities related to S. agalactiae infection. The suspected colonies of S. agalactiae identified by biochemical methods was observed as Gram-positive chained cocci, β-hemolytic, and non-motile. The isolate was confirmed as S. agalactiae by VITEK 2 (99% similarity), reconfirmed by 16S rRNA gene sequencing (99% similarity) and deposited in GenBank with accession no. KT869025. The isolate was observed to be resistance to neomycin and gentamicin. The most consistent gross findings were marked hemorrhages, erosions of caudal fin, and exophthalmos. Microscopic examination confirmed the presence of marked congestion and infiltration of inflammatory cell in the eye, brain, kidney, liver, and spleen. Eye samples showed damage of the lens capsule, hyperemic and hemorrhagic choroid tissue, and retina

  1. Molecular identification and histopathological study of natural Streptococcus agalactiae infection in hybrid tilapia (Oreochromis niloticus

    Directory of Open Access Journals (Sweden)

    Laith Abdul Razzak

    2017-01-01

    Full Text Available Aim: The main objective of this study was to emphasize on histopathological examinations and molecular identification of Streptococcus agalactiae isolated from natural infections in hybrid tilapia (Oreochromis niloticus in Temerloh Pahang, Malaysia, as well as to determine the susceptibility of the pathogen strains to various currently available antimicrobial agents. Materials and Methods: The diseased fishes were observed for variable clinical signs including fin hemorrhages, alterations in behavior associated with erratic swimming, exophthalmia, and mortality. Tissue samples from the eyes, brain, kidney, liver, and spleen were taken for bacterial isolation. Identification of S. agalactiae was screened by biochemical methods and confirmed by VITEK 2 and 16S rRNA gene sequencing. The antibiogram profiling of the isolate was tested against 18 standard antibiotics included nitrofurantoin, flumequine, florfenicol, amoxylin, doxycycline, oleandomycin, tetracycline, ampicillin, lincomycin, colistin sulfate, oxolinic acid, novobiocin, spiramycin, erythromycin, fosfomycin, neomycin, gentamycin, and polymyxin B. The histopathological analysis of eyes, brain, liver, kidney, and spleen was observed for abnormalities related to S. agalactiae infection. Results: The suspected colonies of S. agalactiae identified by biochemical methods was observed as Gram-positive chained cocci, β-hemolytic, and non-motile. The isolate was confirmed as S. agalactiae by VITEK 2 (99% similarity, reconfirmed by 16S rRNA gene sequencing (99% similarity and deposited in GenBank with accession no. KT869025. The isolate was observed to be resistance to neomycin and gentamicin. The most consistent gross findings were marked hemorrhages, erosions of caudal fin, and exophthalmos. Microscopic examination confirmed the presence of marked congestion and infiltration of inflammatory cell in the eye, brain, kidney, liver, and spleen. Eye samples showed damage of the lens capsule

  2. Molecular epidemiology of Streptococcus agalactiae isolated from mastitis in Brazilian dairy herds.

    Science.gov (United States)

    Carvalho-Castro, Glei A; Silva, Juliana R; Paiva, Luciano V; Custódio, Dircéia A C; Moreira, Rafael O; Mian, Glaucia F; Prado, Ingrid A; Chalfun-Junior, Antônio; Costa, Geraldo M

    Streptococcus agalactiae is one of the most common pathogens leading to mastitis in dairy herds worldwide; consequently, the pathogen causes major economic losses for affected farmers. In this study, multilocus sequence typing (MLST), genotypic capsular typing by multiplex polymerase chain reaction (PCR), and virulence gene detection were performed to address the molecular epidemiology of 59 bovine (mastitis) S. agalactiae isolates from 36 dairy farms located in the largest milk-producing mesoregions in Brazil (Minas Gerais, São Paulo, Paraná, and Pernambuco). We screened for the virulence genes bac, bca, bibA, cfb, hylB, fbsA, fbsB, PI-1, PI-2a, and PI-2b, which are associated with adhesion, invasion, tissue damage, and/or immune evasion. Furthermore, five capsular types were identified (Ia, Ib, II, III, and IV), and a few isolates were classified as non-typeable (NT). MLST revealed the following eight sequence types (STs): ST-61, ST-67, ST-103, ST-146, ST-226, ST-314, and ST-570, which were clustered in five clonal complexes (CC64, CC67, CC103, CC17, and CC314), and one singleton, ST-91. Among the virulence genes screened in this study, PI-2b, fbsB, cfb, and hylB appear to be the most important during mastitis development in cattle. Collectively, these results establish the molecular epidemiology of S. agalactiae isolated from cows in Brazilian herds. We believe that the data presented here provide a foundation for future research aimed at developing and implementing new preventative and treatment options for mastitis caused by S. agalactiae. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  3. Molecular epidemiology of Streptococcus agalactiae isolated from mastitis in Brazilian dairy herds

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    Glei A. Carvalho-Castro

    Full Text Available Abstract Streptococcus agalactiae is one of the most common pathogens leading to mastitis in dairy herds worldwide; consequently, the pathogen causes major economic losses for affected farmers. In this study, multilocus sequence typing (MLST, genotypic capsular typing by multiplex polymerase chain reaction (PCR, and virulence gene detection were performed to address the molecular epidemiology of 59 bovine (mastitis S. agalactiae isolates from 36 dairy farms located in the largest milk-producing mesoregions in Brazil (Minas Gerais, São Paulo, Paraná, and Pernambuco. We screened for the virulence genes bac, bca, bibA, cfb, hylB, fbsA, fbsB, PI-1, PI-2a, and PI-2b, which are associated with adhesion, invasion, tissue damage, and/or immune evasion. Furthermore, five capsular types were identified (Ia, Ib, II, III, and IV, and a few isolates were classified as non-typeable (NT. MLST revealed the following eight sequence types (STs: ST-61, ST-67, ST-103, ST-146, ST-226, ST-314, and ST-570, which were clustered in five clonal complexes (CC64, CC67, CC103, CC17, and CC314, and one singleton, ST-91. Among the virulence genes screened in this study, PI-2b, fbsB, cfb, and hylB appear to be the most important during mastitis development in cattle. Collectively, these results establish the molecular epidemiology of S. agalactiae isolated from cows in Brazilian herds. We believe that the data presented here provide a foundation for future research aimed at developing and implementing new preventative and treatment options for mastitis caused by S. agalactiae.

  4. The economic benefit of treating subclinical Streptococcus agalactiae mastitis in lactating cows.

    Science.gov (United States)

    Yamagata, M; Goodger, W J; Weaver, L; Franti, C

    1987-12-15

    The economic benefits of treating lactating cows for Streptococcus agalactiae mastitis were studied at a large (689 milking cows) central California dairy. Postcure milk production of case cows (infected, treated, and cured) was compared with production of paired control cows (uninfected) and was matched for yield, days in milk, days in gestation, and parity. A simulation was used to plot expected lactation curves for mastitic cows (infected, not treated) with characteristics similar to those of each control cow, and these curves were compared with actual case-cow lactation curves. The difference in actual and expected production was used to calculate net economic benefits of treatment. Comparison of expected with actual production indicated a net benefit from treatment of $396/cow for cows treated in early lactation and $237 for cows treated in midlactation, but a net loss of $55 for cows treated in late lactation. Lactation number did not have a significant impact on economic benefits of treatment. In contrast to other studies indicating no economic benefit from treating mastitis during lactation, this study's positive results may have been attributable to the high cure rate (98%) and the subclinical form of mastitis being treated. Streptococcus agalactiae mastitis treatment during early and midlactation would appear to be an economically justifiable option for dairy managers.

  5. Meningoencephalitis in farmed monosex Nile tilapia (Oreochromis niloticus L. caused by Streptococcus agalactiae

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    Adikesavalu Harresh

    2017-09-01

    Full Text Available Aquaculture of tilapia is a new research venture in India. With intensification in farming practices, tilapia are increasingly susceptible to bacterial infections. This article describes the isolation and identification of pathogenic bacteria from cultured monosex Nile tilapia, Oreochromis niloticus (L., that experienced moderate to severe mortalities in West Bengal, India between September and August 2014 and histopathological alterations in various organs. Gram-positive diplococci, identified as Streptococcus agalactiae with Streptococcus identification kits and 16S rDNA sequencing analysis, were isolated from the brain, operculum, and kidney. Other bacteria from the kidney were identified as Aeromonas sobria, A. caviae, Klebsiella pneumoniae ssp. pneumoniae, Escherichia coli, and Enterobacter cloacae. Staphylococcus epidermis was isolated from opercular hemorrhages. Histological sections of the infected tilapia brain revealed meningoencephalitis and granulomatous lesions. Sections from other organs indicated congestion, hemorrhagic and hyperplastic cells, necrosis, vacuolation, hemosiderin deposition, hypertrophic nuclei, melanomacrophage aggregation, and ruptured veins. This report is the first description of S. agalactiae as a primary pathogen causing meningoencephalitis in cultured tilapia in India.

  6. Resistance of Nile tilapia (Oreochromis niloticus) to Streptococcus iniae and S. agalactiae Ib is heritable but not correlated

    Science.gov (United States)

    Tilapia (Oreochromis sp.) are an important source of protein with an economic value approaching US $8 billion yearly. Streptococcal disease, caused by Streptococcus iniae and S. agalactiae (both Gram positive bacteria), is an emerging or re-emerging disease negatively affecting tilapia aquaculture w...

  7. Natural Mutations in Streptococcus agalactiae Resulting in Abrogation of β Antigen Production.

    Science.gov (United States)

    Vasilyeva, Anastasia; Santos Sanches, Ilda; Florindo, Carlos; Dmitriev, Alexander

    2015-01-01

    Streptococcus agalactiae genome encodes 21 two-component systems (TCS) and a variety of regulatory proteins in order to control gene expression. One of the TCS, BgrRS, comprising the BgrR DNA-binding regulatory protein and BgrS sensor histidine kinase, was discovered within a putative virulence island. BgrRS influences cell metabolism and positively control the expression of bac gene, coding for β antigen at transcriptional level. Inactivation of bgrR abrogated bac gene expression and increased virulence properties of S. agalactiae. In this study, a total of 140 strains were screened for the presence of bac gene, and the TCS bgrR and bgrS genes. A total of 53 strains carried the bac, bgrR and bgrS genes. Most of them (48 strains) expressed β antigen, while five strains did not express β antigen. Three strains, in which bac gene sequence was intact, while bgrR and/or bgrS genes had mutations, and expression of β antigen was absent, were complemented with a constructed plasmid pBgrRS(P) encoding functionally active bgrR and bgrS gene alleles. This procedure restored expression of β antigen indicating the crucial regulatory role of TCS BgrRS. The complemented strain A49V/BgrRS demonstrated attenuated virulence in intraperitoneal mice model of S. agalactiae infection compared to parental strain A49V. In conclusion we showed that disruption of β antigen expression is associated with: i) insertion of ISSa4 upstream the bac gene just after the ribosomal binding site; ii) point mutation G342A resulting a stop codon TGA within the bac gene and a truncated form of β antigen; iii) single deletion (G) in position 439 of the bgrR gene resulting in a frameshift and the loss of DNA-binding domain of the BgrR protein, and iv) single base substitutions in bgrR and bgrS genes causing single amino acid substitutions in BgrR (Arg187Lys) and BgrS (Arg252Gln). The fact that BgrRS negatively controls virulent properties of S. agalactiae gives a novel clue for understanding of S

  8. Draft Genome Sequence of Streptococcus agalactiae Serotype Ia Strain M19, a Multidrug-Resistant Isolate from a Cow with Bovine Mastitis

    OpenAIRE

    Yang, Feng; Li, Hongsheng; Zhang, Shidong; Wang, Xurong

    2016-01-01

    Streptococcus agalactiae is a major contagious pathogen causing bovine mastitis worldwide. We report here the draft sequence of S.?agalactiae Ia strain M19, a multidrug-resistant isolate from a bovine mastitis case in Ningxia Hui autonomous region, China.

  9. Streptococcus agalactiae in elephants - A comparative study with isolates from human and zoo animal and livestock origin.

    Science.gov (United States)

    Eisenberg, Tobias; Rau, Jörg; Westerhüs, Uta; Knauf-Witzens, Tobias; Fawzy, Ahmad; Schlez, Karen; Zschöck, Michael; Prenger-Berninghoff, Ellen; Heydel, Carsten; Sting, Reinhard; Glaeser, Stefanie P; Pulami, Dipen; van der Linden, Mark; Ewers, Christa

    2017-05-01

    Streptococcus (S.) agalactiae represents a significant pathogen for humans and animals. However, there are only a few elderly reports on S. agalactiae infections in wild and zoo elephants even though this pathogen has been isolated comparatively frequently in these endangered animal species. Consequently, between 2004 and 2015, we collected S. agalactiae isolates from African and Asian elephants (n=23) living in four different zoos in Germany. These isolates were characterised and compared with isolates from other animal species (n=20 isolates) and humans (n=3). We found that the isolates from elephants can be readily identified by classical biochemistry and MALDI-TOF mass spectrometry. Further characterisations for epidemiological issues were achieved using Fourier transform-infrared spectroscopy, capsule typing and molecular fingerprinting (PFGE, RAPD PCR). We could demonstrate that our elephant isolate collection contained at least six different lineages that were representative for their source of origin. Despite generally broad antimicrobial susceptibility of S. agalactiae, many showed tetracycline resistance in vitro. S. agalactiae plays an important role in bacterial infections not only in cattle and humans, but also in elephants. Comparative studies were able to differentiate S. agalactiae isolates from elephants into different infectious clusters based on their epidemiological background. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. New Mutations of Penicillin-Binding Proteins in Streptococcus agalactiae Isolates from Cattle with Decreased Susceptibility to Penicillin.

    Science.gov (United States)

    Hu, Yun; Kan, Yunchao; Zhang, Zhengtian; Lu, Zhanning; Li, Yanqiu; Leng, Chaoliang; Ji, Jun; Song, Shiyang; Shi, Hongfei

    2018-02-23

    Streptococcus agalactiae is a causal agent of bovine mastitis and is treated by β-lactam antibiotics (BLAs). Compared to penicillin-resistant S. agalactiae from humans, resistant strains in bovine are rarely reported. In this study, we aimed to investigate BLA resistance and mutations in penicillin-binding proteins (PBPs) of S. agalactiae in central and northeast China. The minimum inhibitory concentrations (MICs) of 129 penicillin-resistant S. agalactiae isolates from cows with mastitis were determined, and the related PBP genes were detected and sequenced. All strains were unsusceptible to penicillin G and mostly resistant to ampicillin, cefalexin, and ceftiofur sodium. One hundred twenty-nine strains were divided into 4 clonal groups and 8 sequence types by multilocus sequence typing analysis. We found a set of new substitutions in PBP1B, PBP2B, and PBP2X from most strains isolated from three provinces. The strains with high PBP mutations showed a broader unsusceptible spectrum and higher MICs than those with few or single mutation. Our research indicates unpredicted mutations in the PBP genes of S. agalactiae isolated from cows with mastitis treated by BLAs. This screening is the first of S. agalactiae from cattle.

  11. Serotypes, antibiotic susceptibilities, and multi-locus sequence type profiles of Streptococcus agalactiae isolates circulating in Beijing, China.

    Science.gov (United States)

    Wang, Ping; Tong, Jing-jing; Ma, Xiu-hua; Song, Feng-li; Fan, Ling; Guo, Cui-mei; Shi, Wei; Yu, Sang-jie; Yao, Kai-hu; Yang, Yong-hong

    2015-01-01

    To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the prevention and treatment of S. agalactiae infections. All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles. In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB. S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB.

  12. Protective efficacy of cationic-PLGA microspheres loaded with DNA vaccine encoding the sip gene of Streptococcus agalactiae in tilapia.

    Science.gov (United States)

    Ma, Yan-Ping; Ke, Hao; Liang, Zhi-Ling; Ma, Jiang-Yao; Hao, Le; Liu, Zhen-Xing

    2017-07-01

    Streptococcus agalactiae (S. agalactiae) is an important fish pathogen, which has received more attention in the past decade due to the increasing economic losses in the tilapia industry worldwide. As existing effective vaccines of S. agalactiae in fish have obvious disadvantage, to select immunoprotective antigens and package materials would undoubtedly contribute to the development of novel oral vaccines. In the present study, surface immunogenic protein (sip) was selected from the S. agalactiae serovar I a genomes as immunogenic protein in DNA vaccine form with cationic chitosan and biodegradable and biocompatible PLGA. The pcSip plasmid in cationic-PLGA was successfully expressed in tissues of immunized tilapia and the immunogenicity was assessed in tilapia challenge model. A significant increase was observed in the cytokine levels of IL-1β, TNF-α, CC1, CC2 in spleen and kidney tissues. Furthermore, immunized tilapia conferred different levels of protection against challenge with a lethal dose of highly virulent serovar I a S. agalactiae. Our results indicated that the pcSip plasmid in cationic-PLGA induced high level of antibodies and protection against S. agalactiae infection, could be effective oral DNA vaccine candidates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Screening for group B Streptococcus (GBS) at labour onset using PCR: accuracy and potential impact - a pilot study.

    Science.gov (United States)

    Ramesh Babu, Sandhya; McDermott, Rachel; Farooq, Irum; Le Blanc, David; Ferguson, Wendy; McCallion, Naomi; Drew, Richard; Eogan, Maeve

    2018-01-01

    This pilot study assessed the diagnostic accuracy and potential impact of a rapid PCR-based screening test for the detection of group B Streptococcus (GBS) at the onset of labour for the purpose of optimising intrapartum antibiotic prophylaxis (IAP). Vaginal and rectal swabs from a convenience sample of 158 women were analysed by conventional broth-enriched culture and a rapid PCR test. Overall, GBS carriage was 18.98% by culture and 19.62% by PCR. PCR for the detection of GBS had a sensitivity of 93.1%, specificity of 96.67% and area under the curve (AUC) of 0.95. Only 19.3% GBS-positive women received IAP. Three-fourths of babies born to GBS-positive mothers did not receive surveillance for early-onset GBS disease. Of the women who received IAP, only 32.5% were GBS carriers. Seventy-four percent of the GBS-positive mothers delivered more than 5 h after recruitment, which gives adequate swab to delivery interval for appropriate antibiotic prophylaxis in labour. Impact statement What is already known about this subject: Appropriate intra-partum treatment of colonized mothers reduces the risk of GBS transmission to neonates. Universal ante partum screening of pregnant women or IAP based on risk factors in labour for GBS prevention fail to accurately identify and treat the woman who actually harbors GBS in the birth canal in labour. A PCR based rapid test, allows for real-time assessment of GBS carriage in labour. This study highlights the fact that a large number of GBS carriers in labour, who could potentially infect their babies, do not receive IAP, and most of their babies do not receive added surveillance in the neonatal period for EOGBS disease. It also confirms that PCR testing at onset of labour is a highly sensitive and reliable test that identifies the women who are GBS carriers in labour and hence need IAP. What the implications are of these findings for clinical practice and/or further research: Timely provision of IAP for the appropriate woman is

  14. Additive genetic variation in resistance of Nile tilapia (Oreochromis niloticus) to Streptococcus iniae and S. agalactiae capsular type Ib: is genetic resistance correlated?

    Science.gov (United States)

    Streptococcus (S.) iniae and S. agalactiae are both economically important Gram positive bacterial pathogens affecting the globally farmed tilapia (Oreochromis spp.). Historically control of these bacteria in tilapia culture has included biosecurity, therapeutants and vaccination strategies. Genet...

  15. Combination of garlic - shatterstone herb powder to control Streptococcus agalactiae infection in tilapia

    Directory of Open Access Journals (Sweden)

    Ririn Nurul Fauziah

    2015-10-01

    Full Text Available ABSTRACT This study was aimed at determining potential of combination powder of garlic Allium sativum-shatterstone herb Phyllanthus niruri supplemented in feed against S. agalactiae infection in tilapia. Four concentrations of combination powder of A. sativum-P. Niruri; 20+5, 20+10, 20+15 and 20+20 ppt respectively were investigated for their ability to inhibit bacterial fish pathogen. Combination dose of 20+15 ppt produced the highest inhibitory zones in in vitro test. In vivo test consisted of three treatments with three replications, namely positive control (K+, negative control (K- and the treatment of A. sativum-P. niruri suplemented in feed (BM.  The test perfomed on tilapia with weight of 10.33 ± 1.63 g and were reared at density of 10 ind/aquarium. The fish was fed for 14 days, then injected intraperitoneally with 0.1 mL S. agalactiae at concentration of 105 cfu/mL for positive control and BM groups. Survival, growth rate, feed response, hematological and water quality parameters were observed for 10 days. This study showed that the suplemented-feed-fish (BM showed better growth rate, feed response, and survival (83.3% than positive control (36.7% at P<0.05. In addition, A. sativum-P. niruri suplemented in feed was also able to enhance the immune response by increasing phagocytic activity. Keywords: Streptococcus agalactiae, phytopharmacy, Allium sativum-Phyllanthus niruri, tilapia  ABSTRAK Penelitian ini bertujuan untuk menganalisis potensi campuran tepung bawang putih Allium sativum-meniran Phyllanthus niruri dalam pakan terhadap pencegahan infeksi bakteri S. agalactiae pada ikan nila. Empat konsentrasi campuran tepung bawang putih-meniran yaitu 20+5 ppt, 20+10 ppt, 20+15 ppt dan 20+20 ppt masing-masing diuji kemampuannya dalam  menghambat bakteri patogen pada ikan. Campuran dosis 20+15 ppt menghasilkan zona hambat terbaik dalam uji in vitro. Uji in vivo terdiri atas tiga perlakuan dengan tiga ulangan yaitu kontrol positif

  16. Effect of the Streptococcus agalactiae Virulence Regulator CovR on the Pathogenesis of Urinary Tract Infection.

    Science.gov (United States)

    Sullivan, Matthew J; Leclercq, Sophie Y; Ipe, Deepak S; Carey, Alison J; Smith, Joshua P; Voller, Nathan; Cripps, Allan W; Ulett, Glen C

    2017-02-01

    Streptococcus agalactiae can cause urinary tract infection (UTI). The role of the S. agalactiae global virulence regulator, CovR, in UTI pathogenesis is unknown. We used murine and human bladder uroepithelial cell models of UTI and S. agalactiae mutants in covR and related factors, including β-hemolysin/cytolysin (β-h/c), surface-anchored adhesin HvgA, and capsule to study the role of CovR in UTI. We found that covR-deficient serotype III S. agalactiae 874391 was significantly attenuated for colonization in mice and adhesion to uroepithelial cells. Mice infected with covR-deficient S. agalactiae produced less proinflammatory cytokines than those infected with wild-type 874391. Acute cytotoxicity in uroepithelial cells triggered by covR-deficient but not wild-type 874391 was associated with significant caspase 3 activation. Mechanistically, covR mutation significantly altered the expression of several genes in S. agalactiae 874391 that encode key virulence factors, including β-h/c and HvgA, but not capsule. Subsequent mutational analyses revealed that HvgA and capsule, but not the β-h/c, exerted significant effects on colonization of the murine urinary tract in vivo. S. agalactiae CovR promotes bladder infection and inflammation, as well as adhesion to and viability of uroepithelial cells. The pathogenesis of S. agalactiae UTI is complex, multifactorial, and influenced by virulence effects of CovR, HvgA, and capsule. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  17. Major surfome and secretome profile of Streptococcus agalactiae from Nile tilapia (Oreochromis niloticus): Insight into vaccine development.

    Science.gov (United States)

    Li, Wei; Wang, Hai-Qing; He, Run-Zhen; Li, Yan-Wei; Su, You-Lu; Li, An-Xing

    2016-08-01

    Streptococcus agalactiae is a major piscine pathogen that is responsible for huge economic losses to the aquaculture industry. Safe recombinant vaccines, based on a small number of antigenic proteins, are emerging as the most attractive, cost-effective solution against S. agalactiae. The proteins of S. agalactiae exposed to the environment, including surface proteins and secretory proteins, are important targets for the immune system and they are likely to be good vaccine candidates. To obtain a precise profile of its surface proteins, S. agalactiae strain THN0901, which was isolated from tilapia (Oreochromis niloticus), was treated with proteinase K to cleave surface-exposed proteins, which were identified by liquid chromatography-tandem spectrometry (LC-MS/MS). Forty surface-associated proteins were identified, including ten proteins containing cell wall-anchoring motifs, eight lipoproteins, eleven membrane proteins, seven secretory proteins, three cytoplasmic proteins, and one unknown protein. In addition, culture supernatant proteins of S. agalactiae were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and all of the Coomassie-stained bands were subsequently identified by LC-MS/MS. A total of twenty-six extracellular proteins were identified, including eleven secretory proteins, seven cell wall proteins, three membrane proteins, two cytoplasmic proteins and three unknown proteins. Of these, six highly expressed surface-associated and secretory proteins are putative to be vaccine candidate of piscine S. agalactiae. Moreover, immunogenic secreted protein, a highly expressed protein screened from the secretome in the present study, was demonstrated to induce high antibody titer in tilapia, and it conferred protection against S. agalactiae, as evidenced by the relative percent survival (RPS) 48.61± 8.45%. The data reported here narrow the scope of screening protective antigens, and provide guidance in the development of a novel

  18. Multicentre epidemiological survey on the incidence of Streptococcus agalactiae in pregnancy

    Directory of Open Access Journals (Sweden)

    Leonardo Lodolo

    2010-03-01

    Full Text Available ß-hemolytic streptococci group B (GBS cause infections of the urinary tract, endometrium, amnion, and superinfection of wounds, with complications in 2% -4% of cases in pregnant woman.The infection transmitted to newborns is a cause of sepsis and meningitis with high incidence of mortality.A recent report on a multicentric study of the ISS, showed that detection of S. agalactiae in pregnant women in different realities of healthcare, ranging from 3.9% to 19.4%. This survey covers a sample of 29607 women screened in a total of 36852 childbirths, with a positivity of 4183 subjects equal to 14.1%. Thanks to the GBS Study Group of Piemonte and Valle d’Aosta microbiology laboratories, with the support of 42 study centres have been involved. Collection techniques, types of medium, environmental of incubation of the culture, possible enrichment in broth, of the swabs of 28491 women during 2006/2007 have been considered. 24.36% were vaginal swab while 75.64% vagino/rectal. According to data collected at 31 centers with eligible data (22,175 pregnant GBS positivity was 12.7% (CI [Confidence Interval] + / -95%: 13.1% -12.2% with wide variability between individual centers (2% -22.6%. The enrichment broth is used by 6 out of 9 centers with positivity> 15% (M: 20.05%, from 6 to 14 with positivity between 10-15% (M: 12.61%, from none to 8 centers with less than 10% positivity (M: 4.95%.This multicentre survey underlined the preference for vagino/rectal swab, as recommended by the literature. The frequency of GBS positivity of pregnant women on the whole samples is similar to that found in other national surveys, even if with large differences between the different centers.The sensitivity tends to increase with the use of enrichment techniques, whose use is uneven between the centers, perhaps indicating the need for greater uniformity of protocols based on the results of microbiological analysis EBM (Evidence Based Medicine.

  19. First report of Streptococcus agalactiae isolated from Oreochromis niloticus in Piura, Peru: Molecular identification and histopathological lesions

    Directory of Open Access Journals (Sweden)

    Yessica Ortega Asencios

    2016-11-01

    Full Text Available The aim of this study was to identify the bacterium Streptococcus agalactiae isolated in farmed Nile tilapia (Oreochromis niloticus from Piura, Peru and to characterize the histopathological lesions caused by this pathogen. Sixteen tilapias were sampled with clinic signs of the disease such as erratic swimming, exophthalmia and haemorrhages on the body and fins. Qualitative PCR in real time and histopathological analysis were performed. Nine fishes positives to S. agalactiae were found. The main histopathological findings were fibrinosuppurative epicarditis, periesplenitis, meninigitis and panophtaltmitis with predominance of mononuclear infiltration in all tissues. The correlation between qPCR and histopathological findings demonstrated nine fish (prevalence of 56.25% with Cq lower than 30, associated to high degree of tissue injuries. This study reports the first isolation of S. agalactiae by PCR in real time in tilapia farmed in Peru and characterizes the major histopathological changes caused by this bacterium.

  20. INHIBITION OF Malus sylvestris Mill. PEELEXTRACT USING ETANOL SOLVENT ON THE GROWTH OF Streptococcus agalactiae AND Escherichia coli CAUSING MASTITIS

    Directory of Open Access Journals (Sweden)

    Kanzul Kamal Putra

    2017-03-01

    Full Text Available The purpose of this research was to find the resistibility of Manalagi apple peel extract, using etanol, to the growth of was to determine the antibacterial activity of Manalagi apple peel (Malus sylvestris Mill extract in various solvent using ethanol concentration against the growth of Streptococcus agalactiae and Escherichia coli bacteria that causing mastitis.The research methodwas experimental using Completely Randomized Design with 4 treatments and 6 replication. The treatments consisted of P1 (10%, P2 (20%, P3 (50% concentrations and P0 (10% iodips as the control. The variable measured was diameter of inhibition zone. The data were analyzed using ANOVA and continued by Duncan’s New Multiple Range Test (DMRT test if there was significantly difference result. The result of the inhibition zone of Manalagi apple peel extract using etanol in preventing the growth of Streptococcus agalactiae and Escherichia coli bacteria was different (P<0,01. In P2 (30% concentration, the extract resistibility to the growth of Streptococcus agalactiae bacteria was equivalent to P0 (iodips and in P3 (50% concentration, the extract resistibility to Escherichia coli bacteria was greater than P0 (iodips. Manalagi apple peel extract using etanol can be used as a natural antiseptic solution for teat dipping on dairy cows. The recommendation from the research was using extract Manalagi apple peel with etanol solvent concentration of 30% as a solution of teat dipping.   Keywords : Manalagi apple peel, Teat dipping, Mastitis, Streptococcus agalactiaeand Escherichia coli

  1. Molecular epidemiology and strain-specific characteristics of Streptococcus agalactiae at the herd and cow level.

    Science.gov (United States)

    Mahmmod, Y S; Klaas, I C; Katholm, J; Lutton, M; Zadoks, R N

    2015-10-01

    Host-adaptation of Streptococcus agalactiae subpopulations has been described whereby strains that are commonly associated with asymptomatic carriage or disease in people differ phenotypically and genotypically from those causing mastitis in dairy cattle. Based on multilocus sequence typing (MLST), the most common strains in dairy herds in Denmark belong to sequence types (ST) that are also frequently found in people. The aim of this study was to describe epidemiological and diagnostic characteristics of such strains in relation to bovine mastitis. Among 1,199 cattle from 6 herds, cow-level prevalence of S. agalactiae was estimated to be 27.4% based on PCR and 7.8% based on bacteriological culture. Quarter-level prevalence was estimated at 2.8% based on bacteriological culture. Per herd, between 2 and 26 isolates were characterized by pulsed-field gel electrophoresis (PFGE) and MLST. Within each herd, a single PFGE type and ST predominated, consistent with a contagious mode of transmission or point source infection within herds. Evidence of within-herd evolution of S. agalactiae was detected with both typing methods, although ST belonged to a single clonal complex (CC) per herd. Detection of CC23 (3 herds) was associated with significantly lower approximate count (colony-forming units) at the quarter level and significantly lower cycle threshold value at the cow level than detection of CC1 (2 herds) or CC19 (1 herd), indicating a lower bacterial load in CC23 infections. Median values for the number of infected quarters and somatic cell count (SCC) were numerically but not significantly lower for cows infected with CC23 than for cows with CC1 or CC19. For all CC, an SCC threshold of 200,000 cells/mL was an unreliable indicator of infection status, and prescreening of animals based on SCC as part of S. agalactiae detection and eradication campaigns should be discouraged. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights

  2. Investigation of the translation-initiation factor IF2 gene, infB, as a tool to study the population structure of Streptococcus agalactiae

    DEFF Research Database (Denmark)

    Hedegaard, J; Hauge, M; Fage-Larsen, J

    2000-01-01

    The sequence of infB, encoding the prokaryotic translation-initiation factor 2 (IF2), was determined in eight strains of Streptococcus agalactiae (group B streptococcus) and an alignment revealed limited intraspecies diversity within S. agalactiae. The amino acid sequence of IF2 from S. agalactiae...... and from related species were aligned and revealed an interspecies conserved central and C-terminal part, and an N-terminal part that is highly variable in length and amino acid sequence. The diversity and relationships in a collection of 58 genetically distinct strains of S. agalactiae were evaluated...... by comparing a partial sequence of infB. A total of six alleles were detected for the region of infB analysed. The alleles correlated with the separation of the same strains of S. agalactiae into major evolutionary lineages, as shown in previous work. The partial sequences of infB were furthermore used...

  3. The Adc/Lmb System Mediates Zinc Acquisition in Streptococcus agalactiae and Contributes to Bacterial Growth and Survival.

    Science.gov (United States)

    Moulin, Pauline; Patron, Kévin; Cano, Camille; Zorgani, Mohamed Amine; Camiade, Emilie; Borezée-Durant, Elise; Rosenau, Agnès; Mereghetti, Laurent; Hiron, Aurélia

    2016-12-15

    The Lmb protein of Streptococcus agalactiae is described as an adhesin that binds laminin, a component of the human extracellular matrix. In this study, we revealed a new role for this protein in zinc uptake. We also identified two Lmb homologs, AdcA and AdcAII, redundant binding proteins that combine with the AdcCB translocon to form a zinc-ABC transporter. Expression of this transporter is controlled by the zinc concentration in the medium through the zinc-dependent regulator AdcR. Triple deletion of lmb, adcA, and adcAII, or that of the adcCB genes, impaired growth and cell separation in a zinc-restricted environment. Moreover, we found that this Adc zinc-ABC transporter promotes S. agalactiae growth and survival in some human biological fluids, suggesting that it contributes to the infection process. These results indicated that zinc has biologically vital functions in S. agalactiae and that, under the conditions tested, the Adc/Lmb transporter constitutes the main zinc acquisition system of the bacterium. A zinc transporter, composed of three redundant binding proteins (Lmb, AdcA, and AdcAII), was characterized in Streptococcus agalactiae This system was shown to be essential for bacterial growth and morphology in zinc-restricted environments, including human biological fluids. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  4. Identification of a virulence-related surface protein XF in piscine Streptococcus agalactiae by pre-absorbed immunoproteomics.

    Science.gov (United States)

    Liu, Guangjin; Zhang, Wei; Liu, Yongjie; Yao, Huochun; Lu, Chengping; Xu, Pao

    2014-10-26

    Since 2009, large-scale Streptococcus agalactiae infections have broken out in cultured tilapia farms in China, resulting in considerable economic losses. Screening of the surface proteins is required to identify virulence factors or protective antigens involved in piscine S.agalactiae infections in tilapia. Pre-absorbed immunoproteomics method (PAIM) is a useful method previously established in our laboratory for identifying bacterial surface proteins. A serine-rich repeat protein family 1 (Srr-1), designated XF, was identified by PAIM in piscine S. agalactiae isolate GD201008-001. To investigate the role of XF in the pathogenesis of piscine S. agalactiae, an isogenic xf mutant strain (Δxf) and a complemented strain (CΔxf) were successfully constructed. The Δxf mutant and CΔxf showed no significant differences in growth characteristics and adherence to HEp-2 cells compared with the wild-type strain. However the 50% lethal dose of Δxf was increased (4-fold) compared with that of the parental strain in a zebrafish infection model. The findings demonstrated that XF is a virulence-related, highly immunoreactive surface protein and is involved in the pathogenicity of S. agalactiae infections in fish.

  5. Development of a quantitative PCR assay for monitoring Streptococcus agalactiae colonization and tissue tropism in experimentally infected tilapia.

    Science.gov (United States)

    Su, Y-L; Feng, J; Li, Y-W; Bai, J-S; Li, A-X

    2016-02-01

    Streptococcus agalactiae has become one of the most important emerging pathogens in the aquaculture industry and has resulted in large economic losses for tilapia farms in China. In this study, three pairs of specific primers were designed and tested for their specificities and sensitivities in quantitative real-time polymerase chain reactions (qPCRs) after optimization of the annealing temperature. The primer pair IGS-s/IGS-a, which targets the 16S-23S rRNA intergenic spacer region, was finally chosen, having a detection limit of 8.6 copies of S. agalactiae DNA in a 20 μL reaction mixture. Bacterial tissue tropism was demonstrated by qPCR in Oreochromis niloticus 5 days post-injection with a virulent S. agalactiae strain. Bacterial loads were detected at the highest level in brain, followed by moderately high levels in kidney, heart, spleen, intestines, and eye. Significantly lower bacterial loads were observed in muscle, gill and liver. In addition, significantly lower bacterial loads were observed in the brain of convalescent O. niloticus 14 days post-injection with several different S. agalactiae strains. The qPCR for the detection of S. agalactiae developed in this study provides a quantitative tool for investigating bacterial tissue tropism in infected fish, as well as for monitoring bacterial colonization in convalescent fish. © 2015 John Wiley & Sons Ltd.

  6. Isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in laboratory settings.

    Science.gov (United States)

    Qudratullah; Muhammad, G; Saqib, M; Bilal, M Qamar

    2017-08-01

    The present study was designed to investigate isolation, characterization, virulence and immunogenicity testing of field isolates of Pasteurella multocida, Staphylococcus aureus, and Streptococcus agalactiae in rabbits and mice. Isolates of P. multocida, S. aureus and Str. agalactiae recovered from field cases of Hemorragic septicemia and mastitis were scrutinized for virulence/pathogenicity and immunogenicity. Mouse LD 50 of P. multocida showed that P. multocida isolate No.1 was more virulent than isolates No. 2 and 3. Virulence of isolate No.1S. aureus and Str. agalactiae revealed that 100, 80% rabbits died within 18h of inoculation. Seven-digit numerical profiles of these 4 isolates with API ® Staph test strips isolates, No.1 (6736153) showed good identification (S. aureus id=90.3%). Indirect ELISA-based serum antibody titers to P. multocida isolate No.1, S. aureus No.1, Str. agalactiae, isolate No.1 elicited high antibody titers 1.9, 1.23, 1.12 respectively. All the pathogens of Isolate No. 1 (P. multocida, S. aureus Str. agalactiae), were high antibody than others isolates. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Streptococcus agalactiae isolates of serotypes Ia, III and V from human and cow are able to infect tilapia.

    Science.gov (United States)

    Chen, Ming; Wang, Rui; Luo, Fu-Guang; Huang, Yan; Liang, Wan-Wen; Huang, Ting; Lei, Ai-Ying; Gan, Xi; Li, Li-Ping

    2015-10-22

    Recent studies have shown that group B streptococcus (GBS) may be infectious across hosts. The purpose of this study is to investigate the pathogenicity of clinical GBS isolates with serotypes Ia, III and V from human and cow to tilapia and the evolutionary relationship among these GBS strains of different sources. A total of 27 clinical GBS isolates from human (n=10), cow (n=2) and tilapia (n=15) were analyzed using serotyping, multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Among them, 15 isolates were tested for their pathogenicity to tilapia. The results showed that five human GBS strains (2 serotype III, 2 serotype Ia and 1 serotype V) infected tilapia with mortality rate ranging from 56.67% to 100%, while the other five human GBS strains tested were unable to infect tilapia. In addition, two cow GBS strains C001 and C003 of serotype III infected tilapia. However, they had significantly lower pathogenicity than the five human strains. Furthermore, human GBS strains H005 and H008, which had very strong ability to infect tilapia, had the same PFGE pattern. MLST analysis showed that the five human and the two cow GBS strains that were able to infect tilapia belonged to clonal complexes CC19, CC23 and CC103. The study for the first time confirmed that human or cow GBS clonal complexes CC19, CC23 and CC103 containing strains with serotypes Ia, III and V could infect tilapia and induce clinical signs under experimental conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Complete Atrioventricular Block Complicating Mitral Infective Endocarditis Caused by Streptococcus Agalactiae.

    Science.gov (United States)

    Arai, Masaru; Nagashima, Koichi; Kato, Mahoto; Akutsu, Naotaka; Hayase, Misa; Ogura, Kanako; Iwasawa, Yukino; Aizawa, Yoshihiro; Saito, Yuki; Okumura, Yasuo; Nishimaki, Haruna; Masuda, Shinobu; Hirayama, Astushi

    2016-09-08

    BACKGROUND Infective endocarditis (IE) involving the mitral valve can but rarely lead to complete atrioventricular block (CAVB). CASE REPORT A 74-year-old man with a history of infective endocarditis caused by Streptococcus gordonii (S. gordonii) presented to our emergency room with fever and loss of appetite, which had lasted for 5 days. On admission, results of serologic tests pointed to severe infection. Electrocardiography showed normal sinus rhythm with first-degree atrioventricular block and incomplete right bundle branch block, and transthoracic echocardiography and transesophageal echocardiography revealed severe mitral regurgitation caused by posterior leaflet perforation and 2 vegetations (5 mm and 6 mm) on the tricuspid valve. The patient was initially treated with ceftriaxone and gentamycin because blood and cutaneous ulcer cultures yielded S. agalactiae. On hospital day 2, however, sudden CAVB requiring transvenous pacing occurred, and the patient's heart failure and infection worsened. Although an emergent surgery is strongly recommended, even in patients with uncontrolled heart failure or infection, surgery was not performed because of the Child-Pugh class B liver cirrhosis. Despite intensive therapy, the patient's condition further deteriorated, and he died on hospital day 16. On postmortem examination, a 2×1-cm vegetation was seen on the perforated posterior mitral leaflet, and the infection had extended to the interventricular septum. Histologic examination revealed extensive necrosis of the AV node. CONCLUSIONS This rare case of CAVB resulting from S. agalactiae IE points to the fact that in monitoring patients with IE involving the mitral valve, clinicians should be aware of the potential for perivalvular extension of the infection, which can lead to fatal heart block.

  9. Molecular mapping of the cell wall polysaccharides of the human pathogen Streptococcus agalactiae

    Science.gov (United States)

    Beaussart, Audrey; Péchoux, Christine; Trieu-Cuot, Patrick; Hols, Pascal; Mistou, Michel-Yves; Dufrêne, Yves F.

    2014-11-01

    The surface of many bacterial pathogens is covered with polysaccharides that play important roles in mediating pathogen-host interactions. In Streptococcus agalactiae, the capsular polysaccharide (CPS) is recognized as a major virulence factor while the group B carbohydrate (GBC) is crucial for peptidoglycan biosynthesis and cell division. Despite the important roles of CPS and GBC, there is little information available on the molecular organization of these glycopolymers on the cell surface. Here, we use atomic force microscopy (AFM) and transmission electron microscopy (TEM) to analyze the nanoscale distribution of CPS and GBC in wild-type (WT) and mutant strains of S. agalactiae. TEM analyses reveal that in WT bacteria, peptidoglycan is covered with a very thin (few nm) layer of GBC (the ``pellicle'') overlaid by a 15-45 nm thick layer of CPS (the ``capsule''). AFM-based single-molecule mapping with specific antibody probes shows that CPS is exposed on WT cells, while it is hardly detected on mutant cells impaired in CPS production (ΔcpsE mutant). By contrast, both TEM and AFM show that CPS is over-expressed in mutant cells altered in GBC expression (ΔgbcO mutant), indicating that the production of the two surface glycopolymers is coordinated in WT cells. In addition, AFM topographic imaging and molecular mapping with specific lectin probes demonstrate that removal of CPS (ΔcpsE), but not of GBC (ΔgbcO), leads to the exposure of peptidoglycan, organized into 25 nm wide bands running parallel to the septum. These results indicate that CPS forms a homogeneous barrier protecting the underlying peptidoglycan from environmental exposure, while the presence of GBC does not prevent peptidoglycan detection. This work shows that single-molecule AFM, combined with high-resolution TEM, represents a powerful platform for analysing the molecular arrangement of the cell wall polymers of bacterial pathogens.

  10. A combined enrichment/polymerase chain reaction based method for the routine screening of Streptococcus agalactiae in pregnant women

    Directory of Open Access Journals (Sweden)

    F.M. Munari

    2012-03-01

    Full Text Available Group B Streptococcus (GBS is the most common cause of life-threatening infection in neonates. Guidelines from CDC recommend universal screening of pregnant women for rectovaginal GBS colonization. The objective of this study was to compare the performance of a combined enrichment/PCR based method targeting the atr gene in relation to culture using enrichment with selective broth medium (standard method to identify the presence of GBS in pregnant women. Rectovaginal GBS samples from women at ≥36 weeks of pregnancy were obtained with a swab and analyzed by the two methods. A total of 89 samples were evaluated. The prevalence of positive results for GBS detection was considerable higher when assessed by the combined enrichment/PCR method than with the standard method (35.9% versus 22.5%, respectively. The results demonstrated that the use of selective enrichment broth followed by PCR targeting the atr gene is a highly sensitive, specific and accurate test for GBS screening in pregnant women, allowing the detection of the bacteria even in lightly colonized patients. This PCR methodology may provide a useful diagnostic tool for GBS detection and contributes for a more accurate and effective intrapartum antibiotic and lower newborn mortality and morbidity.

  11. Spatiotemporal patterns, annual baseline and movement-related incidence of Streptococcus agalactiae infection in Danish dairy herds: 2000-2009.

    Science.gov (United States)

    Mweu, Marshal M; Nielsen, Søren S; Halasa, Tariq; Toft, Nils

    2014-02-01

    Several decades after the inception of the five-point plan for the control of contagious mastitis pathogens, Streptococcus agalactiae (S. agalactiae) persists as a fundamental threat to the dairy industry in many countries. A better understanding of the relative importance of within- and between-herd sources of new herd infections coupled with the spatiotemporal distribution of the infection, may aid in effective targeting of control efforts. Thus, the objectives of this study were: (1) to describe the spatiotemporal patterns of infection with S. agalactiae in the population of Danish dairy herds from 2000 to 2009 and (2) to estimate the annual herd-level baseline and movement-related incidence risks of S. agalactiae infection over the 10-year period. The analysis involved registry data on bacteriological culture of all bulk tank milk samples collected as part of the mandatory Danish S. agalactiae surveillance scheme as well as live cattle movements into dairy herds during the specified 10-year period. The results indicated that the predicted risk of a herd becoming infected with S. agalactiae varied spatiotemporally; the risk being more homogeneous and higher in the period after 2005. Additionally, the annual baseline risks yielded significant yet distinctive patterns before and after 2005 - the risk of infection being higher in the latter phase. On the contrary, the annual movement-related risks revealed a non-significant pattern over the 10-year period. There was neither evidence for spatial clustering of cases relative to the population of herds at risk nor spatial dependency between herds. Nevertheless, the results signal a need to beef up within-herd biosecurity in order to reduce the risk of new herd infections. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. The Efficacy of Nile Tilapia (Oreochromis niloticus Broodstock and Larval Immunization against Streptococcus agalactiae and Aeromonas hydrophila

    Directory of Open Access Journals (Sweden)

    Wesly Pasaribu

    2018-03-01

    Full Text Available Streptococcus agalactiae and Aeromonas hydrophila have been recognized as the causative agents of mortality in tilapia larvae with single infection and coinfection. The objective of this study was to evaluate the efficacy of maternal transfer and offspring protection from the immunization of monovalent and bivalent vaccines on Nile tilapia (Oreochromis niloticus broodstock and larval immunization. Four groups of broodstock were intraperitoneally injected with formalin killed whole-cells of S. agalactiae (Sa group, A. hydrophila (Ah group, the bivalent mixed vaccine of them (Biv group, and phosphate-buffered saline as a control (Pbs group. Immunization of the larvae produced from immunized broodstock with a bivalent vaccine (Biv1 group and Pbs (Pbs1 group was performed by immersion at 20 days after hatch. Larvae produced from the Pbs group were unvaccinated as the control (Pbs2 group. Changes in the specific antibody and relative percent survival were measured. The Sa and Ah groups that could increase specific antibodies and protection against pathogenic bacteria were challenged with the homologous bacteria. The Biv group stimulated and protected against both S. agalactiae and A. hydrophila. The specific antibody of the Biv1 group was higher than the Pbs1 and Pbs2 groups. The last observation in this study showed that the relative percent survival of the Biv group after challenged S. agalactiae, A. hydrophila, and coinfection were 74.74 ± 3.18%, 73.81 ± 8.58%, and 71.48 ± 5.70%, respectively. The use of bivalent vaccines on the broodstock and larvae may be a strategy to reduce mortality in Nile tilapia larvae caused by single pathogen infection of S. agalactiae and A. hydrophila, or coinfection with both S. agalactiae and A. hydrophila.

  13. Two novel functions of hyaluronidase from Streptococcus agalactiae are enhanced intracellular survival and inhibition of proinflammatory cytokine expression.

    Science.gov (United States)

    Wang, Zhaofei; Guo, Changming; Xu, Yannan; Liu, Guangjin; Lu, Chengping; Liu, Yongjie

    2014-06-01

    Streptococcus agalactiae is the causative agent of septicemia and meningitis in fish. Previous studies have shown that hyaluronidase (Hyl) is an important virulence factor in many Gram-positive bacteria. To investigate the role of S. agalactiae Hyl during interaction with macrophages, we inactivated the gene encoding extracellular hyaluronidase, hylB, in a clinical Hyl(+) isolate. The isogenic hylb mutant (Δhylb) displayed reduced survival in macrophages compared to the wild type and stimulated a significantly higher release of proinflammatory cytokines, such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α), than the wild type in macrophages as well as in mice. Furthermore, only Hyl(+) strains could grow utilizing hyaluronic acid (HA) as the sole carbon source, suggesting that Hyl permits the organism to utilize host HA as an energy source. Fifty percent lethal dose (LD50) determinations in zebrafish demonstrated that the hylb mutant was highly attenuated relative to the wild-type strain. Experimental infection of BALB/c mice revealed that bacterial loads in the blood, spleen, and brain at 16 h postinfection were significantly reduced in the ΔhylB mutant compared to those in wild-type-infected mice. In conclusion, hyaluronidase has a strong influence on the intracellular survival of S. agalactiae and proinflammatory cytokine expression, suggesting that it plays a key role in S. agalactiae pathogenicity.

  14. Molecular and functional characterization of CD59 from Nile tilapia (Oreochromis niloticus) involved in the immune response to Streptococcus agalactiae.

    Science.gov (United States)

    Gan, Zhen; Wang, Bei; Zhou, Wei; Lu, Yishan; Zhu, Weiwei; Tang, Jufen; Jian, JiChang; Wu, Zaohe

    2015-05-01

    CD59, the major inhibitor of membrane attack complex, plays a crucial role in regulation of complement activation. In this paper, a CD59 gene of Nile tilapia, Oreochromis niloticus (designated as On-CD59) was cloned and its expression pattern under the stimulation of Streptococcus agalactiae was investigated. Sequence analysis showed main structural features required for complement-inhibitory activity were detected in the deduced amino acid sequence of On-CD59. In healthy Nile tilapia, the On-CD59 transcripts could be detected in all the examined tissues, with the most abundant expression in the brain. When immunized with inactivated S. agalactiae, there was a clear time-dependent expression pattern of On-CD59 in the skin, brain, head kidney, thymus and spleen, with quite different kinetic expressions. The assays for the complement-inhibitory activity suggested that recombinant On-CD59 protein had a species-selective inhibition of complement. Moreover, our works showed that recombinant On-CD59 protein may possess both binding activities to PGN and LTA and inhibiting activity of S. agalactiae. These findings indicated that On-CD59 may play important roles in the immune response to S. agalactiae in Nile tilapia. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Development of a loop-mediated isothermal amplification assay for the detection of Streptococcus agalactiae in bovine milk.

    Science.gov (United States)

    Bosward, Katrina L; House, John K; Deveridge, Amber; Mathews, Karen; Sheehy, Paul A

    2016-03-01

    Streptococcus agalactiae is a well-characterized bovine mastitis pathogen that is known to be highly contagious and capable of spreading rapidly in affected dairy herds. Loop-mediated isothermal amplification (LAMP) is a novel molecular diagnostic method that has the capability to provide rapid, cost-effective screening for pathogens to support on-farm disease control and eradication programs. In the current study, a LAMP test was developed to detect S. agalactiae in milk. The assay was validated on a bank of existing clinical mastitis milk samples that had previously been identified as S. agalactiae positive via traditional microbiological culture techniques and PCR. The LAMP assay was conducted on bacterial colonies and DNA extracted from milk in tube- and plate-based formats using multiple detection platforms. The 1-h assay conducted at 64 °C exhibited repeatability (coefficient of variation) of 2.07% (tube) and 8.3% (plate), sensitivity to ~20 pg of extracted DNA/reaction, and specificity against a panel of known bacterial mastitis pathogens. Of the 109 known S. agalactiae isolates assessed by LAMP directly from bacterial cells in culture, 108 were identified as positive, in accordance with PCR analysis. The LAMP analysis from the corresponding milk samples indicated that 104 of these milks exhibited a positive amplification curve. Although exhibiting some limitations, this assay provides an opportunity for rapid screening of milk samples to facilitate on-farm management of this pathogen. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Role of the serine-rich surface glycoprotein Srr1 of Streptococcus agalactiae in the pathogenesis of infective endocarditis.

    Directory of Open Access Journals (Sweden)

    Ho Seong Seo

    Full Text Available The binding of bacteria to fibrinogen and platelets are important events in the pathogenesis of infective endocarditis. Srr1 is a serine-rich repeat glycoprotein of Streptococcus agalactiae that binds directly to the Aα chain of human fibrinogen. To assess the impact of Srr1 on the pathogenesis of endocarditis due to S. agalactiae, we first examined the binding of this organism to immobilized human platelets. Strains expressing Srr1 had significantly higher levels of binding to human platelets in vitro, as compared with isogenic Δsrr1 mutants. In addition, platelet binding was inhibited by pretreatment with anti-fibrinogen IgG or purified Srr1 binding region. To assess the contribution of Srr1 to pathogenicity, we compared the relative virulence of S. agalactiae NCTC 10/84 strain and its Δsrr1 mutant in a rat model of endocarditis, where animals were co-infected with the WT and the mutant strains at a 1:1 ratio. At 72 h post-infection, bacterial densities (CFU/g of the WT strain within vegetations, kidneys, and spleens were significantly higher, as compared with the Δsrr1 mutant. These results indicate that Srr1 contributes to the pathogenesis of endocarditis due to S. agalactiae, at least in part through its role in fibrinogen-mediated platelet binding.

  17. Effect of carryover and presampling procedures on the results of real-time PCR used for diagnosis of bovine intramammary infections with Streptococcus agalactiae at routine milk recordings

    DEFF Research Database (Denmark)

    Mahmmod, Yasser; Mweu, Marshal Mutinda; Nielsen, Søren Saxmose

    2014-01-01

    with Streptococcus agalactiae (S. agalactiae) in dairy herds with conventional milking parlours. Misclassification may result in unnecessary costs for treatment and culling. The objectives of this study were to (1) determine the effect of carryover on PCR-positivity for S. agalactiae at different PCR cycle threshold...... (Ct) cut-offs by estimating the between-cow correlation while accounting for the milking order, and (2) evaluate the effect of aseptic presampling procedures (PSP) on PCR-positivity at the different Ct-value cut-offs. The study was conducted in four herds with conventional milking parlours at routine...

  18. The effects of fish gender on susceptibility to acute Streptococcus agalactiae infection in Javanese medaka Oryzias javanicus.

    Science.gov (United States)

    Amal, M N A; Zarif, S T; Suhaiba, M S; Aidil, M R M; Shaqinah, N N; Zamri-Saad, M; Ismail, A

    2017-12-05

    This study describes the susceptibility of different fish gender following acute Streptococcus agalactiae infection by using Javanese medaka Oryzias javanicus as test fish. The fish were grouped into four groups, which were: (1) all-male; (2) all-female; (3) mixed-gender (1 male: 1 female ratio); and (4) control non-infected (1 male: 1 female ratio). The fish in group 1, 2 and 3 were intraperitoneally exposed to 5.4 × 10 8  CFU/mL of S. agalactiae, while for group 4, the fish were exposed using sterile broth. The main clinical signs and histopathological changes of infected Javanese medaka were commonly observed in S. agalactiae infected fishes. However, no difference on clinical signs and histopathological changes of fish in group 1, 2 and 3 were noticed. The Javanese medaka mortality in group 1, 2 and 3 were observed from 4 h post infection (hpi) to 6 hpi, with the cumulative mortality from 3% to 30%. Then, the mortality increased at 12 hpi, with the range from 53% to 80%. However, 100% of the infected fish dead at 24 hpi. No clinical sign, histopathological change and fish mortality recorded in group 4. Generally, the clinical signs, mortality patterns, cumulative mortality and histopathological changes of Javanese medaka infected by S. agalactiae did not show any difference between the all-male, all-female and mixed-gender groups. This indicates that the susceptibility of fish to S. agalactiae infection is not influenced by their gender. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The effect of fish gender on susceptibility to acute Streptococcus agalactiae infection in Javanese medaka Oryzias javanicus.

    Science.gov (United States)

    Amal, M N A; Zarif, S T; Suhaiba, M; Aidil, M R M; Shaqinah, N N; Zamri-Saad, M; Ismail, A

    2017-12-04

    This study describes the susceptibility of different fish gender following acute Streptococcus agalactiae infection by using Javanese medaka Oryzias javanicus as test fish. The fish were grouped into four groups, which were: (1) all-male; (2) all-female; (3) mixed-gender (1 male: 1 female ratio); and (4) control non-infected (1 male: 1 female ratio). The fish in group 1, 2 and 3 were intraperitoneally exposed to 5.4 × 10 8  CFU/ml of S. agalactiae, while for group 4, the fish were exposed using sterile broth. The main clinical signs and histopathological changes of infected Javanese medaka were commonly observed in S. agalactiae infected fishes. However, no difference on clinical signs and histopathological changes of fish in group 1, 2 and 3 were noticed. The Javanese medaka mortality in group 1, 2 and 3 were observed from 4 h post infection (hpi) to 6 hpi, with the cumulative mortality from 3% to 30%. Then, the mortality increased at 12 hpi, with the range from 53% to 80%. However, 100% of the infected fish dead at 24 hpi. No clinical signs, histopathological changes and fish mortality recorded in group 4. Generally, the clinical signs, mortality patterns, cumulative mortality and histopathological changes of Javanese medaka infected by S. agalactiae did not show any difference between the all-male, all-female and mixed-gender groups. This indicates that the susceptibility of fish to S. agalactiae infection is not influenced by their gender. Copyright © 2017. Published by Elsevier Ltd.

  20. ICESag37, a Novel Integrative and Conjugative Element Carrying Antimicrobial Resistance Genes and Potential Virulence Factors in Streptococcus agalactiae.

    Science.gov (United States)

    Zhou, Kaixin; Xie, Lianyan; Han, Lizhong; Guo, Xiaokui; Wang, Yong; Sun, Jingyong

    2017-01-01

    ICE Sag37 , a novel integrative and conjugative element carrying multidrug resistance and potential virulence factors, was characterized in a clinical isolate of Streptococcus agalactiae . Two clinical strains of S. agalactiae , Sag37 and Sag158, were isolated from blood samples of new-borns with bacteremia. Sag37 was highly resistant to erythromycin and tetracycline, and susceptible to levofloxacin and penicillin, while Sag158 was resistant to tetracycline and levofloxacin, and susceptible to erythromycin. Transfer experiments were performed and selection was carried out with suitable antibiotic concentrations. Through mating experiments, the erythromycin resistance gene was found to be transferable from Sag37 to Sag158. Sma I-PFGE revealed a new Sma I fragment, confirming the transfer of the fragment containing the erythromycin resistance gene. Whole genome sequencing and sequence analysis revealed a mobile element, ICE Sag37 , which was characterized using several molecular methods and in silico analyses. ICE Sag37 was excised to generate a covalent circular intermediate, which was transferable to S. agalactiae . Inverse PCR was performed to detect the circular form. A serine family integrase mediated its chromosomal integration into rumA , which is a known hotspot for the integration of streptococcal ICEs. The integration site was confirmed using PCR. ICE Sag37 carried genes for resistance to multiple antibiotics, including erythromycin [ erm(B) ], tetracycline [ tet(O) ], and aminoglycosides [ aadE, aphA , and ant(6) ]. Potential virulence factors, including a two-component signal transduction system ( nisK/nisR ), were also observed in ICE Sag37 . S1-PFGE analysis ruled out the existence of plasmids. ICE Sag37 is the first ICE Sa2603 family-like element identified in S. agalactiae carrying both resistance and potential virulence determinants. It might act as a vehicle for the dissemination of multidrug resistance and pathogenicity among S. agalactiae .

  1. Reactive oxygen species generation mediated by NADPH oxidase and PI3K/Akt pathways contribute to invasion of Streptococcus agalactiae in human endothelial cells.

    Science.gov (United States)

    Oliveira, Jessica Silva Santos de; Santos, Gabriela da Silva; Moraes, João Alfredo; Saliba, Alessandra Mattos; Barja-Fidalgo, Thereza Christina; Mattos-Guaraldi, Ana Luíza; Nagao, Prescilla Emy

    2018-01-01

    BACKGROUND Streptococcus agalactiae can causes sepsis, pneumonia, and meningitis in neonates, the elderly, and immunocompromised patients. Although the virulence properties of S. agalactiae have been partially elucidated, the molecular mechanisms related to reactive oxygen species (ROS) generation in infected human endothelial cells need further investigation. OBJECTIVES This study aimed to evaluate the influence of oxidative stress in human umbilical vein endothelial cells (HUVECs) during S. agalactiae infection. METHODS ROS production during S. agalactiae-HUVEC infection was detected using the probe CM-H2DCFDA. Microfilaments labelled with phalloidin-FITC and p47phox-Alexa 546 conjugated were analysed by immunofluorescence. mRNA levels of p47phox (NADPH oxidase subunit) were assessed using Real Time qRT-PCR. The adherence and intracellular viability of S. agalactiae in HUVECs with or without pre-treatment of DPI, apocynin (NADPH oxidase inhibitors), and LY294002 (PI3K inhibitor) were evaluated by penicillin/gentamicin exclusion. Phosphorylation of p47phox and Akt activation by S. agalactiae were evaluated by immunoblotting analysis. FINDINGS Data showed increased ROS production 15 min after HUVEC infection. Real-Time qRT-PCR and western blotting performed in HUVEC infected with S. agalactiae detected alterations in mRNA levels and activation of p47phox. Pre-treatment of endothelial cells with NADPH oxidase (DPI and apocynin) and PI3K/Akt pathway (LY294002) inhibitors reduced ROS production, bacterial intracellular viability, and generation of actin stress fibres in HUVECs infected with S. agalactiae. CONCLUSIONS ROS generation via the NADPH oxidase pathway contributes to invasion of S. agalactiae in human endothelial cells accompanied by cytoskeletal reorganisation through the PI3K/Akt pathway, which provides novel evidence for the involvement of oxidative stress in S. agalactiae pathogenesis.

  2. Presence and resistance of Streptococcus agalactiae in vaginal specimens of pregnant and adult non-pregnant women and association with other aerobic bacteria.

    Science.gov (United States)

    Numanović, Fatima; Smajlović, Jasmina; Gegić, Merima; Delibegović, Zineta; Bektaš, Sabaheta; Halilović, Emir; Nurkić, Jasmina

    2017-02-01

    Aim To determine the prevalence rate and resistance profile of Streptococcus agalactiae (S. agalactiae) in vaginal swabs of pregnant and adult non-pregnant women in the Tuzla region, Bosnia and Herzegovina (B&H), as well as its association with other aerobic bacteria. Methods This prospective study included 200 women, 100 pregnant and 100 adult non-pregnant. The research was conducted at the Institute of Microbiology, University Clinical Center Tuzla from October to December 2015. Standard aerobic microbiological techniques were used for isolation and identification of S. agalactiae and other aerobic bacteria. Antimicrobial susceptibility was determined by the disk diffusion and microdilution method(VITEK 2/AES instrument). Results Among 200 vaginal swabs, 17 (8.50%) were positive for S. agalactiae, e. g., 7% (7/100) of pregnant and 10% (10/100) of adult non-pregnant women. In the pregnant group, 71.4% (5/7) of S. agalactiae isolates were susceptible to clindamycin and 85.7%(6/7) to erythromycin. In the adult non-pregnant group, only resistance to clindamycin was observed in one patient (1/10; 10%). S. agalactiae as single pathogen was isolated in 57.14% (4/7) of pregnant and 60% (6/10) of adult non-pregnant S. agalactiae positive women. In mixed microbial cultures S. agalactiae was most frequently associated with Enterococcus faecalis and Escherichia coli. Conclusion The rate of S. agalactiae positive women in the population of pregnant and adult non-pregnant women of Tuzla Canton, B&H is comparable with other European countries. Large studies are needed to develop a common national strategy for the prevention of S. agalactiae infection in B&H, especially during pregnancy. Copyright© by the Medical Assotiation of Zenica-Doboj Canton.

  3. Molecular and bacteriological investigation of subclinical mastitis caused by Staphylococcus aureus and Streptococcus agalactiae in domestic bovids from Ismailia, Egypt.

    Science.gov (United States)

    Elhaig, Mahmoud Mohey; Selim, Abdelfattah

    2015-02-01

    A study was carried out to establish the prevalence of subclinical mastitis (SCM) in smallholder dairy farms in Ismailia, Egypt. A total of 340 milking cows and buffaloes were sampled from 60 farms, and 50 nasal swabs were collected from consenting farm workers. Milk samples were subjected to California mastitis test (CMT) and the positive samples were examined by bacterial culture and PCR to identify etiological agents. Based on CMT, the prevalence of SCM was 71.6 % in cattle and 43.5 % in buffaloes while the prevalence was 25.2 % at cow-quarter level and 21.7 % at buffaloes-quarter level. Bacteriological analysis showed that the most frequently identified bacteria were Staphylococcus (S.) aureus (38.3 %) and Streptococcus (Str.) agalactiae (20 %). The diagnostic sensitivity of PCR compared to bacterial culture was superior with S. aureus and Str. agalactiae detection being 41 and 22.6 %, respectively. Furthermore, methicillin-resistant S. aureus (MRSA) strains occurred in 52.2 and 45 % of isolates of animals and workers, respectively. Subclinical mastitis due to S. aureus and Str. agalactiae is endemic in smallholder dairy herds in Ismailia. The occurrence of MRSA in animals and workers highlights a need for wide epidemiological studies of MRSA and adopting control strategies.

  4. Development of a single-dose recombinant CAMP factor entrapping poly(lactide-co-glycolide) microspheres-based vaccine against Streptococcus agalactiae.

    Science.gov (United States)

    Liu, Gang; Yin, Jinhua; Barkema, Herman W; Chen, Liben; Shahid, Muhammad; Szenci, Otto; De Buck, Jeroen; Kastelic, John P; Han, Bo

    2017-03-01

    Streptococcus agalactiae is an important contagious bovine mastitis pathogen. Although it is well controlled and even eradicated in most Northern European and North American dairy herds, the prevalence of this pathogen remains very high in China. However, research on development of a vaccine against S. agalactiae mastitis is scarce. The aims of the present study were to: (1) develop a single-dose vaccine against S. agalactiae based on poly(lactic-co-glycolic acid) (PLGA) microspheres (MS) encapsulated CAMP factor, a conserved virulent protein encoded by S. agalactiae's cfb gene; and (2) evaluate its immunogenicity and protective efficacy in a mouse model. The cfb gene was cloned and expressed in a recombinant Escherichia coli strain Trans1-T1. The CAMP factor was tested to determine a safe dose range and then encapsulated in MS of PLGA (50:50) to assess its release pattern in vitro and immune reaction in vivo. Furthermore, a mouse model and a histopathological assay were developed to evaluate bacterial burden and vaccine efficacy. In the low dosage range (S. agalactiae challenge. Additionally, no pathological lesions were detected in the vaccinated group. Therefore, PLGA-CAMP conferred protective efficacy against S. agalactiae in our mouse model, indicating its potential as a vaccine against S. agalactiae mastitis. Furthermore, the slow-release kinetics of PLGA MS warranted optimism for development of a single-dose vaccine. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  5. Latent class analysis of real time qPCR and bacteriological culturing for the diagnosis of Streptococcus agalactiae in cow composite milk samples

    DEFF Research Database (Denmark)

    Holmøy, Ingrid H.; Toft, Nils; Jørgensen, Hannah J.

    2018-01-01

    Streptococcus agalactiae (S. agalactiae) has re-emerged as a mastitis pathogen among Norwegian dairy cows. The Norwegian cattle health services recommend that infected herds implement measures to eradicate S. agalactiae, this includes a screening of milk samples from all lactating cows....... The performance of the qPCR-test currently in use for this purpose has not been evaluated under field conditions. The objective of this study was to estimate the sensitivity and specificity of the real-time qPCR assay in use in Norway (Mastitis 4 qPCR, DNA Diagnostics A/S, Risskov, Denmark) and compare...... it to conventional bacteriological culturing for detection of S. agalactiae in milk samples. Because none of these tests are considered a perfect reference test, the evaluation was performed using latent class models in a Bayesian analysis. Aseptically collected cow-composite milk samples from 578 cows belonging...

  6. Effect of Excoecaria agallocha on non-specific immune responses and disease resistance of Oreochromis niloticus against Streptococcus agalactiae.

    Science.gov (United States)

    Laith, A A; Mazlan, A G; Effendy, A W; Ambak, M A; Nurhafizah, W W I; Alia, A S; Jabar, A; Najiah, M

    2017-06-01

    The current study was designed to evaluate the effects of Excoecaria agallocha leaf extracts on immune mechanisms and resistance of tilapia, Oreochromis niloticus, after challenge with Streptococcus agalactiae. Fish were divided into 6 groups; groups 1-5 fed with E. agallocha leaf extracts at 10, 20, 30, 40 and 50mgkg -1 level, respectively. Group 6 were fed without extract addition and acted as control. E. agallocha extracts were administered as feed supplement in fish diet for 28days and the hematological, immunological, and growth performance studies were conducted. Fish were infected with S. agalactiae at a dose of 15×105CFUmL -1 and the total white blood cell (WBC), phagocytosis and respiratory burst activities of leukocytes, serum bactericidal activity, lysozyme, total protein, albumin, and globulin levels were monitored and mortalities recorded for 15days post infection. Results revealed that feeding O. niloticus with 50mgkg -1 of E. agallocha enhanced WBC, phagocytic, respiratory burst, serum bactericidal and lysozyme activities on day 28 pre-challenge and on 3rd, 6th, 9th, 12th and 15th day post-challenge as compared to control. Total protein and albumin were not enhanced by E. agallocha diet. E. agallocha increased the survival of fish after challenge with S. agalactiae. The highest mortality rate (97%) was observed in control fish and the lowest mortality (27%) was observed with group fed with 50mgkg -1 extract. The results indicate that dietary intake of E. agallocha methanolic leaf extract in O. niloticus enhances the non-specific immunity and disease resistance against S. agalactiae pathogen. Copyright © 2017. Published by Elsevier Ltd.

  7. An Overview of Vaccination Strategies and Antigen Delivery Systems for Streptococcus agalactiae Vaccines in Nile Tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Munang'andu, Hetron Mweemba; Paul, Joydeb; Evensen, Øystein

    2016-12-13

    Streptococcus agalactiae is an emerging infectious disease adversely affecting Nile tilapia ( Niloticus oreochromis ) production in aquaculture. Research carried out in the last decade has focused on developing protective vaccines using different strategies, although no review has been carried out to evaluate the efficacy of these strategies. The purpose of this review is to provide a synopsis of vaccination strategies and antigen delivery systems currently used for S. agalactiae vaccines in tilapia. Furthermore, as shown herein, current vaccine designs include the use of replicative antigen delivery systems, such as attenuated virulent strains, heterologous vectors and DNA vaccines, while non-replicative vaccines include the inactivated whole cell (IWC) and subunit vaccines encoding different S. agalactiae immunogenic proteins. Intraperitoneal vaccination is the most widely used immunization strategy, although immersion, spray and oral vaccines have also been tried with variable success. Vaccine efficacy is mostly evaluated by use of the intraperitoneal challenge model aimed at evaluating the relative percent survival (RPS) of vaccinated fish. The major limitation with this approach is that it lacks the ability to elucidate the mechanism of vaccine protection at portals of bacterial entry in mucosal organs and prevention of pathology in target organs. Despite this, indications are that the correlates of vaccine protection can be established based on antibody responses and antigen dose, although these parameters require optimization before they can become an integral part of routine vaccine production. Nevertheless, this review shows that different approaches can be used to produce protective vaccines against S. agalactiae in tilapia although there is a need to optimize the measures of vaccine efficacy.

  8. An Overview of Vaccination Strategies and Antigen Delivery Systems for Streptococcus agalactiae Vaccines in Nile Tilapia (Oreochromis niloticus)

    Science.gov (United States)

    Munang’andu, Hetron Mweemba; Paul, Joydeb; Evensen, Øystein

    2016-01-01

    Streptococcus agalactiae is an emerging infectious disease adversely affecting Nile tilapia (Niloticus oreochromis) production in aquaculture. Research carried out in the last decade has focused on developing protective vaccines using different strategies, although no review has been carried out to evaluate the efficacy of these strategies. The purpose of this review is to provide a synopsis of vaccination strategies and antigen delivery systems currently used for S. agalactiae vaccines in tilapia. Furthermore, as shown herein, current vaccine designs include the use of replicative antigen delivery systems, such as attenuated virulent strains, heterologous vectors and DNA vaccines, while non-replicative vaccines include the inactivated whole cell (IWC) and subunit vaccines encoding different S. agalactiae immunogenic proteins. Intraperitoneal vaccination is the most widely used immunization strategy, although immersion, spray and oral vaccines have also been tried with variable success. Vaccine efficacy is mostly evaluated by use of the intraperitoneal challenge model aimed at evaluating the relative percent survival (RPS) of vaccinated fish. The major limitation with this approach is that it lacks the ability to elucidate the mechanism of vaccine protection at portals of bacterial entry in mucosal organs and prevention of pathology in target organs. Despite this, indications are that the correlates of vaccine protection can be established based on antibody responses and antigen dose, although these parameters require optimization before they can become an integral part of routine vaccine production. Nevertheless, this review shows that different approaches can be used to produce protective vaccines against S. agalactiae in tilapia although there is a need to optimize the measures of vaccine efficacy. PMID:27983591

  9. Detection and enumeration of Staphylococcus aureus and Streptococcus agalactiae in milk by Real-Time PCR

    OpenAIRE

    Aline Gerato Dibbern

    2015-01-01

    O presente trabalho foi organizado em dois estudos. O objetivo do primeiro estudo foi determinar o efeito da infecção intramamária (IIM) causada por S. aureus e S. agalactiae na contagem de células somáticas (CCS) e na composição do leite (gordura, proteína, lactose, sólidos totais e extrato seco desengordurado), o efeito da contagem de S. aureus e S. agalactiae sobre a composição do leite e a estimativa da frequência de vacas e de quartos infectados com S. aureus e S. agalactiae por meio da ...

  10. Expression profiles of miRNAs from bovine mammary glands in response to Streptococcus agalactiae-induced mastitis.

    Science.gov (United States)

    Pu, Junhua; Li, Rui; Zhang, Chenglong; Chen, Dan; Liao, Xiangxiang; Zhu, Yihui; Geng, Xiaohan; Ji, Dejun; Mao, Yongjiang; Gong, Yunchen; Yang, Zhangping

    2017-08-01

    This study aimed to describe the expression profiles of microRNAs (miRNAs) from mammary gland tissues collected from dairy cows with Streptococcus agalactiae-induced mastitis and to identify differentially expressed miRNAs related to mastitis. The mammary glands of Chinese Holstein cows were challenged with Streptococcus agalactiae to induce mastitis. Small RNAs were isolated from the mammary tissues of the test and control groups and then sequenced using the Solexa sequencing technology to construct two small RNA libraries. Potential target genes of these differentially expressed miRNAs were predicted using the RNAhybrid software, and KEGG pathways associated with these genes were analysed. A total of 18 555 913 and 20 847 000 effective reads were obtained from the test and control groups, respectively. In total, 373 known and 399 novel miRNAs were detected in the test group, and 358 known and 232 novel miRNAs were uncovered in the control group. A total of 35 differentially expressed miRNAs were identified in the test group compared to the control group, including 10 up-regulated miRNAs and 25 down-regulated miRNAs. Of these miRNAs, miR-223 exhibited the highest degree of up-regulation with an approximately 3-fold increase in expression, whereas miR-26a exhibited the most decreased expression level (more than 2-fold). The RNAhybrid software predicted 18 801 genes as potential targets of these 35 miRNAs. Furthermore, several immune response and signal transduction pathways, including the RIG-I-like receptor signalling pathway, cytosolic DNA sensing pathway and Notch signal pathway, were enriched in these predicted targets. In summary, this study provided experimental evidence for the mechanism underlying the regulation of bovine mastitis by miRNAs and showed that miRNAs might be involved in signal pathways during S. agalactiae-induced mastitis.

  11. Bacterial Hyaluronidase Promotes Ascending GBS Infection and Preterm Birth

    Science.gov (United States)

    Vornhagen, Jay; Quach, Phoenicia; Boldenow, Erica; Merillat, Sean; Whidbey, Christopher; Ngo, Lisa Y.; Adams Waldorf, K. M.

    2016-01-01

    ABSTRACT Preterm birth increases the risk of adverse birth outcomes and is the leading cause of neonatal mortality. A significant cause of preterm birth is in utero infection with vaginal microorganisms. These vaginal microorganisms are often recovered from the amniotic fluid of preterm birth cases. A vaginal microorganism frequently associated with preterm birth is group B streptococcus (GBS), or Streptococcus agalactiae. However, the molecular mechanisms underlying GBS ascension are poorly understood. Here, we describe the role of the GBS hyaluronidase in ascending infection and preterm birth. We show that clinical GBS strains associated with preterm labor or neonatal infections have increased hyaluronidase activity compared to commensal strains obtained from rectovaginal swabs of healthy women. Using a murine model of ascending infection, we show that hyaluronidase activity was associated with increased ascending GBS infection, preterm birth, and fetal demise. Interestingly, hyaluronidase activity reduced uterine inflammation but did not impact placental or fetal inflammation. Our study shows that hyaluronidase activity enables GBS to subvert uterine immune responses, leading to increased rates of ascending infection and preterm birth. These findings have important implications for the development of therapies to prevent in utero infection and preterm birth. PMID:27353757

  12. Bacterial Hyaluronidase Promotes Ascending GBS Infection and Preterm Birth

    Directory of Open Access Journals (Sweden)

    Jay Vornhagen

    2016-06-01

    Full Text Available Preterm birth increases the risk of adverse birth outcomes and is the leading cause of neonatal mortality. A significant cause of preterm birth is in utero infection with vaginal microorganisms. These vaginal microorganisms are often recovered from the amniotic fluid of preterm birth cases. A vaginal microorganism frequently associated with preterm birth is group B streptococcus (GBS, or Streptococcus agalactiae. However, the molecular mechanisms underlying GBS ascension are poorly understood. Here, we describe the role of the GBS hyaluronidase in ascending infection and preterm birth. We show that clinical GBS strains associated with preterm labor or neonatal infections have increased hyaluronidase activity compared to commensal strains obtained from rectovaginal swabs of healthy women. Using a murine model of ascending infection, we show that hyaluronidase activity was associated with increased ascending GBS infection, preterm birth, and fetal demise. Interestingly, hyaluronidase activity reduced uterine inflammation but did not impact placental or fetal inflammation. Our study shows that hyaluronidase activity enables GBS to subvert uterine immune responses, leading to increased rates of ascending infection and preterm birth. These findings have important implications for the development of therapies to prevent in utero infection and preterm birth.

  13. Group B Streptococcus and the Vaginal Microbiota.

    Science.gov (United States)

    Rosen, Geoffrey H; Randis, Tara M; Desai, Purnahamsi V; Sapra, Katherine J; Ma, Bing; Gajer, Pawel; Humphrys, Michael S; Ravel, Jacques; Gelber, Shari E; Ratner, Adam J

    2017-09-15

    Streptococcus agalactiae (group B Streptococcus [GBS]) is an important neonatal pathogen and emerging cause of disease in adults. The major risk factor for neonatal disease is maternal vaginal colonization. However, little is known about the relationship between GBS and vaginal microbiota. Vaginal lavage samples from nonpregnant women were tested for GBS, and amplicon-based sequencing targeting the 16S ribosomal RNA V3-V4 region was performed. Four hundred twenty-eight of 432 samples met the high-quality read threshold. There was no relationship between GBS carriage and demographic characteristics, α-diversity, or overall vaginal microbiota community state type (CST). Within the non-Lactobacillus-dominant CST IV, GBS positive status was significantly more prevalent in CST IV-A than CST IV-B. Significant clustering by GBS status was noted on principal coordinates analysis, and 18 individual taxa were found to be significantly associated with GBS carriage by linear discriminant analysis. After adjusting for race/ethnicity, 4 taxa were positively associated with GBS, and 6 were negatively associated. Vaginal microbiota CST and α-diversity are not related to GBS status. However, specific microbial taxa are associated with colonization of this important human pathogen, highlighting a potential role for the microbiota in promotion or inhibition of GBS colonization. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  14. Pathological analysis, detection of antigens, FasL expression analysis and leucocytes survival analysis in tilapia (Oreochromis niloticus) after infection with green fluorescent protein labeled Streptococcus agalactiae.

    Science.gov (United States)

    Wang, Jingyuan; Wu, Jinying; Yi, Liyuan; Hou, Zengxin; Li, Wensheng

    2017-03-01

    The pathogenesis of Streptococcus agalactiae infection in tilapia has not been fully described. To understand this, we investigated the clinic-pathological features of acute experimental septicemia in tilapia (Oreochromis niloticus) after receiving an intra-peritoneal injection with S. agalactiae THN-1901GFP. Immunohistochemistry and sections of pathological tissues were used to estimate the level of damage in the head-kidney, liver, spleen and trunk-kidney. The expression of FasL was analyzed by western blotting in these samples based on their damage levels. Leucocytes were isolated from the head-kidney and incubated with S. agalactiae THN-1901GFP. Then, phagocytosis, programmed cell death and the expression of FasL were analyzed. The infected tissues showed varying degrees of necrosis and histolysis. The serous membrane of the intestine was dissolved by S. agalactiae THN-1901GFP. Antigens of S. agalactiae THN-1901GFP accumulated in different parts of the infected organs. In the head-kidney and spleen, the expression of FasL was up-regulated in parallel with increased tissue damage. After being incubated with S. agalactiae THN-1901GFP, the phagocytic capacity and ability were both very high and the expression of FasL remained high in leucocytes. S. agalactiae THN-1901GFP was able to survive for a long period of time after being engulfed by phagocytic cells. These findings offer insight into the pathogenesis of S. agalactiae infection in tilapia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Evaluation of the efficacy of intramuscular versus intramammary treatment of subclinical Streptococcus agalactiae mastitis in dairy cows in Colombia.

    Science.gov (United States)

    Reyes, J; Chaffer, M; Sanchez, J; Torres, G; Macias, D; Jaramillo, M; Duque, P C; Ceballos, A; Keefe, G P

    2015-08-01

    A randomized controlled trial was performed in 17 Colombian dairy herds to determine the cure risk among cows subclinically infected with Streptococcus agalactiae exposed to 2 antibiotic therapies. Composite milk samples were collected before milking at the onset of the trial (pretreatment) and 2 subsequent times over a period of approximately 63 d. The intramammary application (IMM) of ampicillin-cloxacillin was compared with the intramuscular application (IM) of penethamate hydriodide, and cure risks after an initial and retreatment application were assessed. Cure risk after the initial treatment was higher (82.4%) for the IMM treatment than for IM therapy (65.8%). However, no difference was observed in the cure risk of refractory cases after retreatment (IMM=52.6% vs. IM=51.2%). The cumulative cure risk (both initial and retreatment) was 90.4 and 82.9% for the IMM and IM products, respectively. A 2-level random effects logistic model that controlled for pretreatment cow-level somatic cell count, indicated that IM treatment (odds ratio=0.37) had a lower cure risk than IMM and a tendency for a lower cure risk with increasing baseline somatic cell count. Our findings suggest that both products and administration routes can reduce the prevalence of S. agalactiae in affected herds, but the IMM product had a better efficacy in curing the infection. In addition to the treatment protocol, the cow somatic cell count should be considered when making management decisions for cows infected with S. agalactiae. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Involvement of cholinergic and adenosinergic systems on the branchial immune response of experimentally infected silver catfish with Streptococcus agalactiae.

    Science.gov (United States)

    Baldissera, M D; Souza, C F; Doleski, P H; Moreira, K L S; da Veiga, M L; da Rocha, M I U M; Santos, R C V; Baldisserotto, B

    2018-01-01

    It has been recognized that the cholinergic and adenosinergic systems have an essential role in immune and inflammatory responses during bacterial fish pathogens, such as the enzymes acetylcholinesterase (AChE) and adenosine deaminase (ADA), which are responsible for catalysis of the anti-inflammatory molecules acetylcholine (ACh) and adenosine (Ado) respectively. Thus, the aim of this study was to investigate the involvement of the cholinergic and adenosinergic systems on the immune response and inflammatory process in gills of experimentally infected Rhamdia quelen with Streptococcus agalactiae. Acetylcholinesterase activity decreased, while ACh levels increased in gills of infected animals compared to uninfected animals. On the other hand, a significant increase in ADA activity with a concomitant decrease in Ado levels was observed in infected animals compared to uninfected animals. Based on this evidence, we concluded that infection by S. agalactiae in silver catfish alters the cholinergic and adenosinergic systems, suggesting the involvement of AChE and ADA activities on immune and inflammatory responses, regulating the ACh and Ado levels. In summary, the downregulation of AChE activity exerts an anti-inflammatory profile in an attempt to reduce or prevent the tissue damage, while the upregulation of ADA activity exerts a pro-inflammatory profile, contributing to disease pathophysiology. © 2017 John Wiley & Sons Ltd.

  17. Optimización de metodologías de cribaje para la búsqueda de Streptococcus agalactiae en embarazadas Optimization of screening methodologies for the detection of Streptococcus agalactiae in pregnant women

    Directory of Open Access Journals (Sweden)

    Silvia E. Montibello

    2011-03-01

    Full Text Available Streptococcus agalactiae es una causa importante de morbimortalidad en mujeres embarazadas y neonatos en todo el mundo. El objetivo del presente trabajo fue determinar la utilidad del medio cromogénico chromID Strepto B de bioMérieux para detectar S. agalactiae en embarazadas cuando la muestra es sembrada directamente en dicho medio o después del enriquecimiento en caldo de Todd Hewitt selectivo, opciones que se compararon con la metodología propuesta por el CDC . Se analizaron 1924 hisopados, 962 de introito vaginal y 962 rectales, correspondientes a 962 embarazadas entre la semana 35 y 37 de gestación, asistidas en distintos hospitales. Los hisopados se sembraron directamente en el medio chromID Strepto B (CR y luego se colocaron en un caldo de Todd Hewitt selectivo, suplementado con 15 µg/ml de ácido nalidíxico y 10 µg/ml de colistina (CTH-sel. Luego de 24 h de incubación, se realizaron subcultivos en el medio CR y en agar con 5% de sangre de carnero (ASO. La prevalencia global de S. agalactiae fue de 17,4%. La sensibilidad, la especificidad y los valores predictivos positivo y negativo del subcultivo en CR del material desarrollado en el CTH -sel fueron 98,8%, 100%, 100% y 99,7% respectivamente, con una incubación de 48 h. Los valores correspondientes de la siembra directa fueron 57,8%, 100%, 100% y 90%. La sensibilidad del subcultivo en ASO del material desarrollado en el CTH -sel fue del 85%. Se destaca el excelente rendimiento del subcultivo en CR luego del enriquecimiento en caldo de Todd Hewitt selectivo en comparación con el método propuesto por el CDC.Streptococcus agalactiae is a significant worldwide cause of morbidity and mortality in pregnant women and their newborn infants. The objective of this work was to determine the usefulness of bioMrieux chromogenic medium chromID Strepto B (CR for detecting S. agalactiae in pregnant women from the selective Todd-Hewitt broth (sel-THB against the methods proposed by the CDC

  18. Biofilm formation, hemolysin production and antimicrobial susceptibilities of Streptococcus agalactiae isolated from the mastitis milk of dairy cows in Shahrekord district, Iran

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    Azizollah Ebrahimi

    2014-12-01

    Full Text Available Streptococcus agalactiae is a major contagious pathogen causing bovine sub-clinical mastitis. The present investigation was carried out to determine some phenotypic characteristics of the S. agalactiae strains isolated from bovine mastitis cases in dairy cows of Shahrekord in the west-center of Iran. One hundred eighty California mastitis test (CMT positive milk samples were bacteriologically studied. A total of 31 (17.2% S. agalactiae isolated. Twenty eight (90.3% of the isolates were biofilm producers. This finding may indicate the high potential of pathogenicity in isolated strains. Sixteen (51.6% isolates were α hemolysin producers. Only 19.3%, 22.5% and 29.0% of the isolates were sensitive to streptomycin, flumequine and kanamycin, respectively. None of these three agents is recommended for treatment of mastitis cases.

  19. Pattern of Infection and Antibiotic Activity among Streptococcus agalactiae Isolates from Adults in Mashhad, Iran

    Directory of Open Access Journals (Sweden)

    Masoumeh Malek-Jafarian

    2015-05-01

    Full Text Available Background: One of the main causes of sexually transmitted diseases is group B β- hemolytic streptococci (GBS multiplying in the genital tracts. Penicillin is the most common drug for the treatment of infections caused by these bacteria, but in patients suffering from Penicillin allergy, Erythromycin and Clindamycin are used as alternative therapeutic drugs against GBS. Recently, resistance to these drugs has been reported more often. In this study, efforts have been made to determine the prevalence and antibiotic resistance of GBS. Methods: Modified Christie Atkins Munch-Petersen (CAMP test was conducted on over 2400 samples of urine and discharge taken from vagina, urethra and prostate. The drug sensitivity was performed by double disk sensitivity tests to Bacitracin, Trimethoprim, and Sulfamethoxazole and then the resistant samples were investigated by E-test to determine the minimal inhibitory concentrations (MICs value. Results: Twenty-three vaginal and 10 urethral discharge, 27urine and 6 prostatic secretion samples were GBS positive. The most symbiotic microorganisms with GBS were strains of Enterococci (90%, Staphylococcus saprophyticus (25% and Candida albicans (6%. The disk diffusion method showed 18 cases with Penicillin resistance (MIC: 1.5 mg/ml. Conclusion: Taken together, GBS carriers’ rate in this study was found 20.65% (8.24% men and 12.4% women. Furthermore, findings showed high-level resistance to Erythromycin and Clindamycin.

  20. In vitro characterization of PlySK1249, a novel phage lysin, and assessment of its antibacterial activity in a mouse model of Streptococcus agalactiae bacteremia.

    Science.gov (United States)

    Oechslin, Frank; Daraspe, Jean; Giddey, Marlyse; Moreillon, Philippe; Resch, Grégory

    2013-12-01

    Beta-hemolytic Streptococcus agalactiae is the leading cause of bacteremia and invasive infections. These diseases are treated with β-lactams or macrolides, but the emergence of less susceptible and even fully resistant strains is a cause for concern. New bacteriophage lysins could be promising alternatives against such organisms. They hydrolyze the bacterial peptidoglycan at the end of the phage cycle, in order to release the phage progeny. By using a bioinformatic approach to screen several beta-hemolytic streptococci, a gene coding for a lysin was identified on a prophage carried by Streptococcus dysgalactiae subsp. equisimilis SK1249. The gene product, named PlySK1249, harbored an original three-domain structure with a central cell wall-binding domain surrounded by an N-terminal amidase and a C-terminal CHAP domain. Purified PlySK1249 was highly lytic and bactericidal for S. dysgalactiae (2-log10 CFU/ml decrease within 15 min). Moreover, it also efficiently killed S. agalactiae (1.5-log10 CFU/ml decrease within 15 min) but not several streptococcal commensal species. We further investigated the activity of PlySK1249 in a mouse model of S. agalactiae bacteremia. Eighty percent of the animals (n = 10) challenged intraperitoneally with 10(6) CFU of S. agalactiae died within 72 h, whereas repeated injections of PlySK1249 (45 mg/kg 3 times within 24 h) significantly protected the mice (P S. dysgalactiae, demonstrated high cross-lytic activity against S. agalactiae both in vitro and in vivo. These encouraging results indicated that PlySK1249 might represent a good candidate to be developed as a new enzybiotic for the treatment of systemic S. agalactiae infections.

  1. Quantitative assessment of the blood-brain barrier opening caused by Streptococcus agalactiae hyaluronidase in a BALB/c mouse model.

    Science.gov (United States)

    Luo, Su; Cao, Qing; Ma, Ke; Wang, Zhaofei; Liu, Guangjin; Lu, Chengping; Liu, Yongjie

    2017-10-19

    Streptococcus agalactiae is a pathogen causing meningitis in animals and humans. However, little is known about the entry of S. agalactiae into brain tissue. In this study, we developed a BALB/c mouse model based on the intravenous injection of β-galactosidase-positive Escherichia coli M5 as an indicator of blood-brain barrier (BBB) opening. Under physiological conditions, the BBB is impermeable to E. coli M5. In pathological conditions caused by S. agalactiae, E. coli M5 is capable of penetrating the brain through a disrupted BBB. The level of BBB opening can be assessed by quantitative measurement of E. coli M5 loads per gram of brain tissue. Further, we used the model to evaluate the role of S. agalactiae hyaluronidase in BBB opening. The inactivation of hylB gene encoding a hyaluronidase, HylB, resulted in significantly decreased E. coli M5 colonization, and the intravenous injection of purified HylB protein induced BBB opening in a dose-dependent manner. This finding verified the direct role of HylB in BBB invasion and traversal, and further demonstrated the practicability of the in vivo mouse model established in this study. This model will help to understand the S. agalactiae-host interactions that are involved in this bacterial traversal of the BBB and to develop efficacious strategies to prevent central nervous system infections.

  2. NATURAL MUTATION IN THE GENE OF RESPONSE REGULATOR BgrR RESULTING IN REPRESSION OF Bac PROTEIN SYNTHESIS, A PATHOGENICITY FACTOR OF STREPTOCOCCUS AGALACTIAE

    Directory of Open Access Journals (Sweden)

    A. S. Rozhdestvenskaya

    2013-01-01

    Full Text Available Abstract. Streptococcus agalactiae can cause variety of diseases of newborns and adults. For successful colonization of different human tissues and organs as well as for suppression of the host immune system S. agalactiae expresses numerous virulence factors. For coordinated expression of the virulence genes S. agalactiae employs regulatory molecules including regulatory proteins of two-component systems. Results of the present study demonstrated that in S. agalactiae strain A49V the natural mutation in the brgR gene encoding for BgrR regulatory protein, which is component of regulatory system BgrRS, resulted in the repression of Bac protein synthesis, a virulence factor of S. agalactiae. A single nucleotide deletion in the bgrR gene has caused a shift of the reading frame and the changes in the primary, secondary and tertiary structures of the BgrR protein. The loss of functional activity of BgrR protein in A49V strain and repression of Bac protein synthesis have increased virulence of the strain in experimental animal streptococcal infection.

  3. Streptococcus agalactiae em gestantes: prevalência de colonização e avaliação da suscetibilidade aos antimicrobianos Streptococcus agalactiae in pregnant women: prevalence of colonization and antimicrobial susceptibility evaluation

    Directory of Open Access Journals (Sweden)

    Irina Lermontov Borger

    2005-10-01

    Full Text Available OBJETIVOS: verificar a ocorrência de colonização por Streptococcus agalactiae em gestantes e avaliar a suscetibilidade das amostras isoladas aos antimicrobianos. MÉTODOS: foram avaliadas 167 grávidas entre a 32ª e a 41ª semana de gestação, independente da presença ou não de fatores de risco, atendidas no ambulatório de pré-natal entre fevereiro de 2003 e fevereiro de 2004. O material vaginal/anal, colhido com um único swab, foi inoculado em caldo Todd-Hewitt acrescido de ácido nalidíxico (15 µg/mL e gentamicina (8 µg/mL, com posterior subcultura no meio de ágar sangue. A identificação foi feita por meio da avaliação da morfologia e tipo de hemólise das colônias no meio de ágar sangue, teste da catalase, teste de cAMP e testes sorológicos. A avaliação da suscetibilidade aos antimicrobianos foi realizada pelos testes de difusão e de diluição em ágar. A análise estatística foi realizada por meio do teste de chi2; valores de p0,05. Todas as 32 amostras isoladas foram sensíveis a penicilina, cefotaxima, ofloxacina, cloranfenicol, vancomicina e meropenem. A resistência a eritromicina e clindamicina foi detectada em 9,4 e 6,2% das amostras, respectivamente. CONCLUSÕES: a incidência relativamente elevada (19,2% de colonização por S. agalactiae entre as gestantes avaliadas e o isolamento de amostras resistentes, especialmente aos antimicrobianos recomendados nos casos de alergia à penicilina, enfatizam a importância de detectar esta colonização no final da gravidez, associada à avaliação da suscetibilidade aos antimicrobianos, para uma prevenção eficaz da infecção neonatal.PURPOSE: to verify the occurrence of colonization by Streptococcus agalactiae in pregnant women attended at the prenatal outpatient clinic of the Teaching Maternity Hospital of Rio de Janeiro University (UFRJ and to evaluate the susceptibility of the isolates to antimicrobial agents. METHODS: a total of 167 pregnant women between the

  4. PENGARUH LAMA DAN SUHU PENYIMPANAN EKSTRAK DAUN SIRIH HIJAU (Piper betle linn) DENGAN AQUADES TERHADAP DAYA HAMBAT BAKTERI Streptococcus agalactiae PENYEBAB MASTITIS PADA SAPI PERAH

    OpenAIRE

    Muhammad Sanjaya Kusuma; Tri Eko Susilorini; Puguh Surjowardojo

    2017-01-01

    Green betle leaf (Piper betle L.) is one of the plants used by the people of Indonesia for tradisional medicine. Green betle leaf contains antibacterial compounds consisting of phenol and its derivatives. This study aims to determine the antibacterial activity of green betle leaf (Piper betle L.) againt the bacteria Streptococcus agalactiae caused mastitis in dairy cows. Bacterial inhibition test by paper disc method. Data analysis using ANOVA by Nested design with 6 treatment and 6 repetitio...

  5. Carriage and serotype distribution of Streptococcus agalactiae in third trimester pregnancy in southern Ghana

    DEFF Research Database (Denmark)

    Slotved, Hans-Christian; Dayie, Nicholas T K D; Banini, Josephine A N

    2017-01-01

    was performed on a single subcultured colony. Gram staining was performed, and isolates were evaluated for beta-haemolytic reactions. Furthermore, the isolates were serotyped using the GBS latex serotyping kit. RESULTS: The carriage rates were found to be 25.5% (95% CI: 19.6-32.1) to 28.0% (95% CI: 21...... of this study revealed that prevalence of GBS colonization in pregnant women in Greater Accra region is high and comparable to rates observed in South Africa and Western countries. The most prevalent serotypes were serotypes VII and IX, which have not been observed before in West Africa....

  6. PENGARUH LAMA DAN SUHU PENYIMPANAN EKSTRAK DAUN SIRIH HIJAU (Piper betle linn DENGAN AQUADES TERHADAP DAYA HAMBAT BAKTERI Streptococcus agalactiae PENYEBAB MASTITIS PADA SAPI PERAH

    Directory of Open Access Journals (Sweden)

    Muhammad Sanjaya Kusuma

    2017-11-01

    Full Text Available Green betle leaf (Piper betle L. is one of the plants used by the people of Indonesia for tradisional medicine. Green betle leaf contains antibacterial compounds consisting of phenol and its derivatives. This study aims to determine the antibacterial activity of green betle leaf (Piper betle L. againt the bacteria Streptococcus agalactiae caused mastitis in dairy cows. Bacterial inhibition test by paper disc method. Data analysis using ANOVA by Nested design with 6 treatment and 6 repetitions. The results of this study green betle leaf (Piper betle L. extract inhibiting the growth of bacteria Streptococcus agalactiae was significantly different (P<0,01. The conclusion were the extract of green betel leaf (Piper betle L. can inhibit the growth of Streptococcus agalactiae and storage temperature has no effect, but storage periode gives effect the quality of green betel leaf extract (Piper betle L., so that the leaf extract storage green betel with distilled solvent recommended on 2nd days at refrigerator.

  7. Desempenho e hematologia de tilápias-do-nilo alimentadas com Saccharomyces cerevisiae e vacinadas contra Streptococcus agalactiae

    Directory of Open Access Journals (Sweden)

    Rogério Salvador

    2013-08-01

    Full Text Available O objetivo deste trabalho foi avaliar a inter-relação entre a suplementação alimentar com parede celular de Saccharomyces cerevisae e a vacinação contra Streptococcus agalactiae e seu efeito sobre o desempenho produtivo e as variáveis hematológicas de tilápia-do-nilo (Oreochromis niloticus. Oitenta e quatro tilápias-do-nilo foram distribuídas em 12 caixas de fibra (n=7, em arranjo fatorial 2x2x3, correspondente a dois níveis de suplementação com parede celular de levedura, dois tipos de inoculação e três tempos de avaliação. Os peixes foram alimentados durante 77 dias. A vacinação dos peixes foi realizada 60 dias após o início da alimentação. Quinze dias após a vacinação, todos os peixes foram submetidos ao desafio com cepa viva de S. agalactiae, e 6, 24 e 48 horas após o desafio, o sangue foi colhido da veia caudal para avaliações. Peixes alimentados com ração suplementada apresentam maior ganho de peso e taxa de crescimento específico, e a interação entre os efeitos da dieta e da vacinação resulta em maiores taxas de hematócrito, hemoglobina e leucócitos.

  8. In vitro antimicrobial susceptibility and genetic resistance determinants of Streptococcus agalactiae isolated from mastitic cows in Brazilian dairy herds

    Directory of Open Access Journals (Sweden)

    Juliana Rosa da Silva

    2017-08-01

    Full Text Available Streptococcus agalactiae is one of the main causative agents of bovine mastitis and is associated with several economic losses for producers. Few studies have evaluated antimicrobial susceptibility and the prevalence of genetic resistance determinants among isolates of this bacterium from Brazilian dairy cattle. This work aimed to evaluate the frequency of the antimicrobial resistance genes ermA, ermB, mefA, tetO, tetM, aphA3, and aad-6, and in vitro susceptibility to the antimicrobials amikacin, erythromycin, clindamycin, tetracycline, gentamicin, penicillin, ceftiofur, and cefalotin, and the associations between resistance genotypes and phenotypes among 118 S. agalactiae isolates obtained from mastitic cows in Brazilian dairy herds. Of the resistance genes examined, ermB was found in 19 isolates (16.1%, tetO in 23 (19.5%, and tetM in 24 (20.3%. The genes ermA, mefA, aphA3, and aad-6 were not identified. There was an association between the presence of genes ermB, tetM, and tetO and phenotypic resistance to erythromycin, clindamycin, and tetracycline. Rates of resistance to the tested antibiotics varied, as follows: erythromycin (19.5%, tetracycline (35.6%, gentamicin (9.3%, clindamycin (20.3%, penicillin (3.4%, and amikacin (38.1%; conversely, all isolates were susceptible to ceftiofur and cefalotin. Antimicrobial resistance testing facilitates the treatment decision process, allowing the most judicious choice of antibiotics. Moreover, it enables regional and temporal monitoring of the resistance dynamics of this pathogen of high importance to human and animal health.

  9. Crystallization and preliminary crystallographic analysis of two Streptococcus agalactiae proteins: the family II inorganic pyrophosphatase and the serine/threonine phosphatase

    International Nuclear Information System (INIS)

    Rantanen, Mika K.; Lehtiö, Lari; Rajagopal, Lakshmi; Rubens, Craig E.; Goldman, Adrian

    2006-01-01

    Two S. agalactiae proteins, the inorganic pyrophosphatase and the serine/threonine phosphatase, were crystallized and diffraction data were collected and processed from these crystals. The data from the two protein crystals extended to 2.80 and 2.65 Å, respectively. Streptococcus agalactiae, which infects human neonates and causes sepsis and meningitis, has recently been shown to possess a eukaryotic-like serine/threonine protein phosphorylation signalling cascade. Through their target proteins, the S. agalactiae Ser/Thr kinase and Ser/Thr phosphatase together control the growth as well as the morphology and virulence of this organism. One of the targets is the S. agalactiae family II inorganic pyrophosphatase. The inorganic pyrophosphatase and the serine/threonine phosphatase have therefore been purified and crystallized and diffraction data have been collected from their crystals. The data were processed using XDS. The inorganic pyrosphosphatase crystals diffracted to 2.80 Å and the Ser/Thr phosphatase crystals to 2.65 Å. Initial structure-solution experiments indicate that structure solution will be successful in both cases. Solving the structure of the proteins involved in this cascade is the first step towards understanding this phenomenon in atomic detail

  10. A novel one-step real-time multiplex PCR assay to detect Streptococcus agalactiae presence and serotypes Ia, Ib, and III.

    Science.gov (United States)

    Furfaro, Lucy L; Chang, Barbara J; Payne, Matthew S

    2017-09-01

    Streptococcus agalactiae is the leading cause of early-onset neonatal sepsis. Culture-based screening methods lack the sensitivity of molecular assays and do not indicate serotype; a potentially important virulence marker. We aimed to develop a multiplex PCR to detect S. agalactiae while simultaneously identifying serotypes Ia, Ib, and III; commonly associated with infant disease. Primers were designed to target S. agalactiae serotype-specific cps genes and the dltS gene. The assay was validated with 512 vaginal specimens from pregnant women. 112 (21.9%) were dltS positive, with 14.3%, 0.9%, and 6.3% of these identified as cps Ia, Ib, and III, respectively. Our assay is a specific and sensitive method to simultaneously detect S. agalactiae and serotypes Ia, Ib, and III in a single step. It is of high significance for clinical diagnostic applications and also provides epidemiological data on serotype, information that may be important for vaccine development and other targeted non-antibiotic therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Crystallization and preliminary crystallographic analysis of two Streptococcus agalactiae proteins: the family II inorganic pyrophosphatase and the serine/threonine phosphatase

    Energy Technology Data Exchange (ETDEWEB)

    Rantanen, Mika K.; Lehtiö, Lari [Institute of Biotechnology, University of Helsinki, PO Box 65, FIN-00014, Helsinki (Finland); Rajagopal, Lakshmi; Rubens, Craig E. [Division of Infectious Disease, Children’s Hospital and Regional Medical Center, Seattle, Washington 98105 (United States); Goldman, Adrian, E-mail: adrian.goldman@helsinki.fi [Institute of Biotechnology, University of Helsinki, PO Box 65, FIN-00014, Helsinki (Finland)

    2006-09-01

    Two S. agalactiae proteins, the inorganic pyrophosphatase and the serine/threonine phosphatase, were crystallized and diffraction data were collected and processed from these crystals. The data from the two protein crystals extended to 2.80 and 2.65 Å, respectively. Streptococcus agalactiae, which infects human neonates and causes sepsis and meningitis, has recently been shown to possess a eukaryotic-like serine/threonine protein phosphorylation signalling cascade. Through their target proteins, the S. agalactiae Ser/Thr kinase and Ser/Thr phosphatase together control the growth as well as the morphology and virulence of this organism. One of the targets is the S. agalactiae family II inorganic pyrophosphatase. The inorganic pyrophosphatase and the serine/threonine phosphatase have therefore been purified and crystallized and diffraction data have been collected from their crystals. The data were processed using XDS. The inorganic pyrosphosphatase crystals diffracted to 2.80 Å and the Ser/Thr phosphatase crystals to 2.65 Å. Initial structure-solution experiments indicate that structure solution will be successful in both cases. Solving the structure of the proteins involved in this cascade is the first step towards understanding this phenomenon in atomic detail.

  12. Laboratory-controlled Challenges of Nile Tilapia (Oreochromis niloticus) with Streptococcus agalactiae: Comparisons between Immersion, Oral, Intracoelomic and Intramuscular Routes of Infection.

    Science.gov (United States)

    Soto, E; Zayas, M; Tobar, J; Illanes, O; Yount, S; Francis, S; Dennis, M M

    2016-11-01

    Streptococcus agalactiae, the aetiological agent of streptococcosis in fish, is an important pathogen of cultured and wild fish worldwide. To gain a better understanding of the pathogenesis of streptococcosis in Nile tilapia (Oreochromis niloticus), and to identify the experimental route of infection that most closely mimics natural disease, fingerlings were challenged with S. agalactiae utilizing different delivery methods. Fingerlings were challenged via intracoelomic injection (ICinj), intramuscular injection (IMinj), orally or by immersion with serial dilutions of S. agalactiae. The dose lethal to 50% of test fish 15 days post challenge was 120 colony forming units (CFU)/fish after ICinj, and 10 5  CFU/fish after IMinj. Acute mortalities were present in both groups, but were higher in the fish challenged by ICinj. Very low mortalities were observed in the fish challenged via oral or immersion routes. Post-mortem evaluation of survivors revealed classical lesions associated with fish streptococcosis, including granulomatous or lymphohistiocytic epicarditis, splenitis, meningitis, myocarditis, choroiditis and exophthalmia. The information obtained improves our understanding of the pathogenesis of streptococcosis in fish, and provides useful information regarding controlled experimental infections in tilapia challenged with S. agalactiae. Results from this study suggest that IMinj challenge methods are not only suitable to induce streptococcosis in tilapia, but they may be the preferred method to study the pathogenesis of the naturally-occurring disease in this species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Molecular and functional characterization of peptidoglycan-recognition protein SC2 (PGRP-SC2) from Nile tilapia (Oreochromis niloticus) involved in the immune response to Streptococcus agalactiae.

    Science.gov (United States)

    Gan, Zhen; Chen, Shannan; Hou, Jing; Huo, Huijun; Zhang, Xiaolin; Ruan, Baiye; Laghari, Zubair Ahmed; Li, Li; Lu, Yishan; Nie, Pin

    2016-07-01

    PGRP-SC2, the member of PGRP family, plays an important role in regulation of innate immune response. In this paper, a PGRP-SC2 gene of Nile tilapia, Oreochromis niloticus (designated as On-PGRP-SC2) was cloned and its expression pattern under the infection of Streptococcus agalactiae was investigated. Sequence analysis showed main structural features required for amidase activity were detected in the deduced amino acid sequence of On-PGRP-SC2. In healthy tilapia, the On-PGRP-SC2 transcripts could be detected in all the examined tissues, with the most abundant expression in the muscle. When infected with S. agalactiae, there was a clear time-dependent expression pattern of On-PGRP-SC2 in the spleen, head kidney and brain. The assays for the amidase activity suggested that recombinant On-PGRP-SC2 protein had a Zn(2+)-dependent PGN-degrading activity. Moreover, our works showed that recombinant On-PGRP-SC2 protein could significantly reduce bacterial load in target organs attacked by S. agalactiae. These findings indicated that On-PGRP-SC2 may play important roles in the immune response to S. agalactiae in Nile tilapia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. RovS and its associated signaling peptide form a cell-to-cell communication system required for Streptococcus agalactiae pathogenesis.

    Science.gov (United States)

    Pérez-Pascual, David; Gaudu, Philippe; Fleuchot, Betty; Besset, Colette; Rosinski-Chupin, Isabelle; Guillot, Alain; Monnet, Véronique; Gardan, Rozenn

    2015-01-20

    Bacteria can communicate with each other to coordinate their biological functions at the population level. In a previous study, we described a cell-to-cell communication system in streptococci that involves a transcriptional regulator belonging to the Rgg family and short hydrophobic peptides (SHPs) that act as signaling molecules. Streptococcus agalactiae, an opportunistic pathogenic bacterium responsible for fatal infections in neonates and immunocompromised adults, has one copy of the shp/rgg locus. The SHP-associated Rgg is called RovS in S. agalactiae. In this study, we found that the SHP/RovS cell-to-cell communication system is active in the strain NEM316 of S. agalactiae, and we identified different partners that are involved in this system, such as the Eep peptidase, the PptAB, and the OppA1-F oligopeptide transporters. We also identified a new target gene controlled by this system and reexamined the regulation of a previously proposed target gene, fbsA, in the context of the SHP-associated RovS system. Furthermore, our results are the first to indicate the SHP/RovS system specificity to host liver and spleen using a murine model, which demonstrates its implication in streptococci virulence. Finally, we observed that SHP/RovS regulation influences S. agalactiae's ability to adhere to and invade HepG2 hepatic cells. Hence, the SHP/RovS cell-to-cell communication system appears to be an essential mechanism that regulates pathogenicity in S. agalactiae and represents an attractive target for the development of new therapeutic strategies. Rgg regulators and their cognate pheromones, called small hydrophobic peptides (SHPs), are present in nearly all streptococcal species. The general pathways of the cell-to-cell communication system in which Rgg and SHP take part are well understood. However, many other players remain unidentified, and the direct targets of the system, as well as its link to virulence, remain unclear. Here, we identified the different players

  15. Construction of a Streptococcus agalactiae phoB mutant and evaluation of its potential as an attenuated modified live vaccine in golden pompano, Trachinotus ovatus.

    Science.gov (United States)

    Cai, Xiaohui; Wang, Bei; Peng, Yinhui; Li, Yuan; Lu, Yishan; Huang, Yucong; Jian, Jichang; Wu, Zaohe

    2017-04-01

    Streptococcus agalactiae is a Gram-positive pathogen that can survive inside professional phagocytes and nonphagocytic cells to cause septicemia and meningoencephalitis in freshwater and marine fish. However, vaccines based on extracellular products (ECP) and formalin-killed whole S. agalactiae cells, as well as subunit vaccine are unable to protect fish from infection by variant serotypes S. agalactiae. The search for live attenuated vaccine with highly conserved and virulent-related genes is essential for producing a vaccine to help understand and control streptococcosis In this study, the phoB gene was cloned from pathogenic S. agalactiae TOS01 strain and the mutant strain SAΔphoB was constructed via allelic exchange mutagenesis. The results showed that the deduced amino acid of S. agalactiae TOS01 shares high similarities with other Streptococcus spp. and has high conserved response regulator receiver domain (REC) and DNA-binding effector domain of two-component system response regulators (Trans_reg_C). Cell adherence and invasion assays, challenge experiments and histopathological changes post-vaccination were performed and observed, the results showed that the mutant strain SAΔphoB has a lower adherence and invasion rate and less virulent than the wild type strain in golden pompano, and it doesn't induce clinical symptoms and obvious pathological changes in golden pompano, thereby indicating that the deletion of phoB affects the virulence and infectious capacity of S. agalactiae. Golden pompano vaccinated via intraperitoneal injection SAΔphoB had the relative percent survival value of 93.1% after challenge with TOS01, demonstrating its high potential as an effective attenuated live vaccine candidate. Real-time PCR assays showed that the SAΔphoB was able to enhance the expression of immune-related genes, including MHC-I, MyD88, IL-22 and IL-10 after vaccination, indicating that the SAΔphoB is able to induce humoral and cell-mediated immune response

  16. Identificação dos sorotipos de Streptococcus agalactiae pela técnica de PCR de amostras isoladas em pacientes colonizados e infectados na cidade de Campinas e região

    OpenAIRE

    Katelí Fiolo

    2011-01-01

    Resumo: Streptococcus agalactiae, conhecido como Estreptococo beta-hemolítico do grupo B (EGB), é classificado por diferenças capsulares que podem variar em dez sorotipos, alguns responsáveis por infecções materno-infantis sérias e debilitantes ou podendo ainda levar ao óbito. O EGB pode ocasionar também, infecções graves em adultos e idosos. OBJETIVO: Descrever e analisar o perfil epidemiológico dos sorotipos prevalentes de Streptococcus agalactiae, provenientes de infecção em recém-nascidos...

  17. Complete Atrioventricular Block Complicating Mitral Infective Endocarditis Caused by Streptococcus Agalactiae

    OpenAIRE

    Arai, Masaru; Nagashima, Koichi; Kato, Mahoto; Akutsu, Naotaka; Hayase, Misa; Ogura, Kanako; Iwasawa, Yukino; Aizawa, Yoshihiro; Saito, Yuki; Okumura, Yasuo; Nishimaki, Haruna; Masuda, Shinobu; Hirayama, Atsushi

    2016-01-01

    Patient: Male, 74 Final Diagnosis: Infective endocarditis Symptoms: Apetite loss ? fever Medication: ? Clinical Procedure: Transesophageal echocardiography Specialty: Cardiology Objective: Rare co-existance of disease or pathology Background: Infective endocarditis (IE) involving the mitral valve can but rarely lead to complete atrioventricular block (CAVB). Case Report: A 74-year-old man with a history of infective endocarditis caused by Streptococcus gordonii (S. gordonii) presented to our ...

  18. Caracterização Genética da Resistência à Eritromicina em Streptococcus agalactia e Degestantes saudáveis

    OpenAIRE

    Pinheiro, Sandra Marisa de Oliveira Sequeira

    2009-01-01

    Dissertação de Mestrado em Biologia Clínica Laboratorial Streptococcus agalactiae (Grupo B de Lancefield, EGB), um microrganismo comensal do homem, reconhecido em 1920 como o agente etiológico da mastite bovina, tem sido associado a infecções em parturientes e recém-nascidos, sendo o principal agente de septicemia e meningite neonatal. Para evitar a infecção perinatal recomenda-se a pesquisa da bactéria na região vagino-perianal durante o terceiro semestre de gravidez, indicando o tratamen...

  19. Genital infections and reproductive complications associated with Trichomonas vaginalis, Neisseria gonorrhoeae, and Streptococcus agalactiae in women of Qom, central Iran

    Directory of Open Access Journals (Sweden)

    Mahmoud Nateghi Rostam

    2017-07-01

    Full Text Available Background: Trichomonas vaginalis (T.vaginalis and Neisseria gonorrhoeae (N.gonorrhoeae are two most common non-viral sexually transmitted infections in the world. No data are available regarding the epidemiology of genital infections in women of Qom, central Iran. Objective: Epidemiological investigation of sexually transmitted infections in genital specimens of women referred to the referral gynecology hospital in Qom, central Iran. Materials and Methods: Genital swab specimens were collected from women volunteers and used for identification of bacterial and protozoal infections by conventional microbial diagnostics, porA pseudo gene LightCycler® real-time PCR (for N.gonorrhoeae and ITS-PCR (for T.vaginalis. Results: Of 420 volunteers, 277 (65.9% had genital signs/symptoms, including 38.3% malodorous discharge, 37.9% dyspareunia, and 54.8% abdominal pain. Totally, 2 isolates of Streptococcus agalactiae were identified. Five specimens (1.2% in Thayer-Martin culture and 17 (4.1% in real-time PCR were identified as N.gonorrhoeae. Fifty-four specimens (12.9% in wet mount, 64 (15.2% in Dorset’s culture, and 81 (19.3% in ITS-PCR showed positive results for T.vaginalis. Five mixed infections of T.vaginalis+ N.gonorrhoeae were found. The risk of T.vaginalis infection was increased in women with low-birth-weight (p=0.00; OR=43.29, history of abortion (p=0.00; OR=91.84, and premature rupture of membranes (PROM (p=0.00; OR=21.75. The probability of finding nuclear leukocytes (p=0.00; OR=43.34 in vaginal smear was higher in T.vaginalis infection. Conclusion: The significant prevalence of trichomoniasis and gonorrhea emphasizes the need for accurate diagnosis and effective surveillance to prevent serious reproductive complications in women.

  20. Distribution of serotypes and evaluation of antimicrobial susceptibility among human and bovine Streptococcus agalactiae strains isolated in Brazil between 1980 and 2006

    Directory of Open Access Journals (Sweden)

    Tatiana Castro Abreu Pinto

    Full Text Available Streptococcus agalactiae is a common agent of clinical and subclinical bovine mastitis and an important cause of human infections, mainly among pregnant women, neonates and nonpregnant adults with underlying diseases. The present study describes the genetic and phenotypic diversity among 392 S. agalactiae human and bovine strains isolated between 1980 and 2006 in Brazil. The most prevalent serotypes were Ia, II, III and V and all the strains were susceptible to penicillin, vancomycin and levofloxacin. Resistance to clindamycin, chloramphenicol, erythromycin, rifampicin and tetracycline was observed. Among the erythromycin resistant strains, mefA/E, ermA and, mainly, ermB gene were detected, and a shift of prevalence from the macrolide resistance phenotype to the macrolidelincosamide- streptogramin B resistance phenotype over the years was observed. The 23 macrolide-resistant strains showed 19 different pulsed-field gel electrophoresis profiles. Regarding macrolide resistance, a major concern in S. agalactiae epidemiology, the present study describes an increase in erythromycin resistance from the 80s to the 90s followed by a decrease in the 2000-2006 period. Also, the genetic heterogeneity described points out that erythromycin resistance in Brazil is rather due to horizontal gene transmission than to spreading of specific macrolide-resistant clones.

  1. Modeling Group B Streptococcus and Blood-Brain Barrier Interaction by Using Induced Pluripotent Stem Cell-Derived Brain Endothelial Cells

    OpenAIRE

    Kim, Brandon J.; Bee, Olivia B.; McDonagh, Maura A.; Stebbins, Matthew J.; Palecek, Sean P.; Doran, Kelly S.; Shusta, Eric V.

    2017-01-01

    ABSTRACT Bacterial meningitis is a serious infection of the central nervous system (CNS) that occurs after bacteria interact with and penetrate the blood-brain barrier (BBB). The BBB is comprised of highly specialized brain microvascular endothelial cells (BMECs) that function to separate the circulation from the CNS and act as a formidable barrier for toxins and pathogens. Certain bacteria, such as Streptococcus agalactiae (group B Streptococcus [GBS]), possess the ability to interact with a...

  2. Bacterial Protein Characterization of Streptococcus agalactiae by SDS-page Method for Subclinical Mastitis Irradiated Vaccine Materials in Dairy Cattle

    International Nuclear Information System (INIS)

    Tuasikal, B.J.; Wibawan, I.W.T.; Pasaribu, F.H; Estuningsih, S.

    2012-01-01

    A study have been conducted to isolate and characterize bacterial protein S. agalactiae, which is antigenic and can be used to test immunogenicity of vaccine in order to manufacture irradiated mastitis (inflammation of the udder) vaccine in ruminant. The study aims to determine the Molecular Weight (MW) bacterial protein S. agalactiae irradiation, which can be used to test the nature of its antigenic caharacteristic. The character of S. agalactiae antigenic stimulates antibody induction of the immune system, in which case is the body's defense system against mastitis disease in cattle. In this study, irradiation of gamma ray is used to attenuate the pathogenicity of bacteria by reducing S. agalactiae antigenic characteristic. Previous research, in irradiation dose orientation before antigenic protein isolation of S. agalactiae, indicated that irradiation lethal dose to 50% (LD 50 ) is 17 Gy. The characterization of S. agalactiae bacteria isolate using SDS-page method results in no significance different between irradiated and non-irradiated group, which indicated by MW range 75 - 100 kDa base on marker standard which used, or 99 kDa by the linier equation of Y = 11,60 - 0.05X (where Y = bands distance; X = MW standard protein); r 2 = 0.99. In conclusion, 17 Gy irradiation dose does not impair antigenic property of S. agalactiae and therefore, can be applied to produce base material of irradiated vaccine for mastitis. (author)

  3. Safety and immunogenicity of an oral DNA vaccine encoding Sip of Streptococcus agalactiae from Nile tilapia Oreochromis niloticus delivered by live attenuated Salmonella typhimurium.

    Science.gov (United States)

    Huang, L Y; Wang, K Y; Xiao, D; Chen, D F; Geng, Y; Wang, J; He, Y; Wang, E L; Huang, J L; Xiao, G Y

    2014-05-01

    Attenuated Salmonella typhimurium SL7207 was used as a carrier for a reconstructed DNA vaccine against Streptococcus agalactiae. A 1.02 kb DNA fragment, encoding for a portion of the surface immunogenic protein (Sip) of S. agalactiae was inserted into pVAX1. The recombinant plasmid pVAX1-sip was transfected in EPC cells to detect the transient expression by an indirect immunofluorescence assay, together with Western blot analysis. The pVAX1-sip was transformed by electroporation into SL7207. The stability of pVAX1-sip into Salmonella was over 90% after 50 generations with antibiotic selection in vitro while remained stable over 80% during 35 generations under antibiotic-free conditions. The LD50 of SL/pVAX1-sip was 1.7 × 10(11) CFU/fish by intragastric administration which indicated a quite low virulence. Tilapias were inoculated orally at 10(8) CFU/fish, the recombinant bacteria were found present in intestinal tract, spleens and livers and eventually eliminated from the tissues 4 weeks after immunization. Fish immunized at 10(7), 10(8) and 10(9) CFU/fish with different immunization times caused various levels of serum antibody and an effective protection against lethal challenge with the wild-type strain S. agalactiae. Integration studies showed that the pVAX1-sip did not integrate with tilapia chromosomes. The DNA vaccine SL/pVAX1-sip was proved to be safe and effective in protecting tilapias against S. agalactiae infection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. A metabolomic investigation into the effects of temperature on Streptococcus agalactiae from Nile tilapia (Oreochromis niloticus) based on UPLC-MS/MS.

    Science.gov (United States)

    Hu, Wen-Ting; Guo, Wei-Liang; Meng, Ai-Yun; Sun, Yun; Wang, Shi-Feng; Xie, Zhen-Yu; Zhou, Yong-Can; He, Chaozu

    2017-10-01

    Streptococcosis caused by Streptococcus agalactiae is one of the most serious diseases in farmed tilapia, and temperature is one of the most important environmental factors related to its outbreak. To elucidate the influence of temperature variation on the pathogen from a metabolic perspective, the global metabolomics of 2 pathogenic strains of S. agalactiae from sick tilapia were analyzed at 35°C and 25°C using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) combined with pattern recognition approaches and pathway analysis. The result showed that the metabolic status of S. agalactiae was extensively affected by its culture temperature. Based on the results of metabolites contributing to these differences, a large number of nucleotides and their ramifications were markedly elevated at 35°C. Various energy substances, components of the cell wall and substances associated with stress regulation such as glyceraldehyde 3-phosphate, pyroglutamic acid, glutamate, d-Alanyl-d-alanine, glycerophosphocholine, dephospho-CoA, and oxidized glutathione increased when the strains were cultured at 35°C. Additionally, a general decrease in various precursors of capsule, antigen, and virulence protein formation were detected including mannose, maltotriose, N-acetyl-d-glucosamine 6-phosphate, uracil, proline, and citrulline. These metabolic changes indicated that metabolic activity decreased, while adaptive ability to environment and pathogenicity to host increased at high temperature. This study is the first to determine the metabolomic responses of S. agalactiae to temperature, and the results are useful to reveal its pathogenic mechanism and find effective disease control. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A new mosaic integrative and conjugative element from Streptococcus agalactiae carrying resistance genes for chloramphenicol (catQ) and macrolides [mef(I) and erm(TR)].

    Science.gov (United States)

    Morici, Eleonora; Simoni, Serena; Brenciani, Andrea; Giovanetti, Eleonora; Varaldo, Pietro E; Mingoia, Marina

    2017-01-01

    To investigate the genetic basis of catQ-mediated chloramphenicol resistance in Streptococcus agalactiae. Two clinical strains of catQ-positive chloramphenicol-resistant S. agalactiae (Sag236 and Sag403) were recently isolated, typed (MLST, PFGE pulsotypes, capsular types) and their antibiotic resistances investigated by phenotypic and genotypic approaches. Several molecular methods (PCR mapping, restriction assays, Southern blotting, sequencing and sequence analysis, conjugal transfer assays) were used to determine the genetic context of catQ and characterize a genetic element detected in the isolates. Sag236 and Sag403 shared the same ST (ST19), but exhibited a different capsular type (III and V, respectively) and pulsotype. Both harboured the macrolide resistance genes mef(I) and erm(TR) and the tetracycline resistance gene tet(M). Accordingly, they were resistant to chloramphenicol, erythromycin and tetracycline. catQ and mef(I) were associated in an IQ module that was indistinguishable in Sag236 and Sag403. In mating assays, chloramphenicol and erythromycin resistance proved transferable, at low frequency, only from Sag236. Transconjugants carried not only catQ and mef(I), but also erm(TR), suggesting a linkage of the three resistance genes in a mobile element, which, though seemingly non-mobile, was also detected in Sag403. The new element (designated ICESag236, ∼110 kb) results from recombination of two integrative and conjugative elements (ICEs) originally described in different streptococcal species: S. agalactiae ICESagTR7, carrying erm(TR); and Streptococcus pneumoniae ICESpn529IQ, carrying the prototype IQ module. These findings strengthen the notion that widespread streptococcal ICEs may form mosaics that enhance their diversity and spread, broaden their host range and carry new cargo genes. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions

  6. Influência da temperatura na infecção de tilápias do Nilo por Streptococcus agalactiae

    Directory of Open Access Journals (Sweden)

    Paulo Fernandes Marcusso

    2015-04-01

    Full Text Available Mudanças ambientais afetam a homeostase dos peixes, tornando-os mais suscetíveis a doenças. No Brasil, tem sido relatados surtos de infecção por Streptococcus agalactiae em tilápia do Nilo, principalmente quando se encontram fora da zona de conforto térmico. No presente trabalho, foi avaliada a taxa de mortalidade e determinado quais foram os órgãos mais afetados por essa bactéria em temperaturas que ocorrem naturalmente no Sul do Brasil. Quarenta tilápias-do-nilo (Oreochromis niloticus foram infectadas por Streptococcus agalactiae e distribuídas em quatro grupos (n = 10, cada um deles submetidos a diferentes temperaturas: G1: 24°C, G2: 26°C, G3: 28°C e G4: 32°C. Os peixes foram monitorados durante 10 dias. Os peixes com sinais clínicos irreversíveis foram sacrificados e coletadas amostras de cérebro, fígado e rins para analise bacteriológica e molecular. Foram observados sinais compatíveis com infecção estreptocócica em todos os grupos. A taxa de mortalidade mais elevada ocorreu nos grupos mantidos nas temperaturas de 24°C e 32°C. O cérebro foi o órgão mais afetado, com a maior percentagem de isolamento de S. agalactiae pelos dois métodos de diagnostico. Os resultados sugerem que, tal como nos mamíferos, temperaturas que estão mais afastadas da zona de conforto afetam significativamente a homeostase dos peixes, aumentando a sua susceptibilidade para infecções bacterianas.

  7. Group B Streptococcus and Pregnancy

    Science.gov (United States)

    ... B Strep and Pregnancy • What is group B streptococcus (GBS)? • What does it mean to be colonized ... planned cesarean birth? •Glossary What is group B streptococcus (GBS)? Group B streptococcus is one of the ...

  8. Gene Regulation in Streptococcus pneumoniae: interplay between nutrition and virulence

    NARCIS (Netherlands)

    W.T. Hendriksen (Wouter)

    2010-01-01

    textabstractStreptococcus pneumoniae (the pneumococcus) is a Gram-positive bacterium, which belongs to the species of streptococci. Other pathogenic bacteria belonging to this class include Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus suis, Streptococcus uberis, Streptococcus

  9. Latent class analysis of real time qPCR and bacteriological culturing for the diagnosis of Streptococcus agalactiae in cow composite milk samples.

    Science.gov (United States)

    Holmøy, Ingrid H; Toft, Nils; Jørgensen, Hannah J; Mørk, Tormod; Sølverød, Liv; Nødtvedt, Ane

    2018-06-01

    Streptococcus agalactiae (S. agalactiae) has re-emerged as a mastitis pathogen among Norwegian dairy cows. The Norwegian cattle health services recommend that infected herds implement measures to eradicate S. agalactiae, this includes a screening of milk samples from all lactating cows. The performance of the qPCR-test currently in use for this purpose has not been evaluated under field conditions. The objective of this study was to estimate the sensitivity and specificity of the real-time qPCR assay in use in Norway (Mastitis 4 qPCR, DNA Diagnostics A/S, Risskov, Denmark) and compare it to conventional bacteriological culturing for detection of S. agalactiae in milk samples. Because none of these tests are considered a perfect reference test, the evaluation was performed using latent class models in a Bayesian analysis. Aseptically collected cow-composite milk samples from 578 cows belonging to 6 herds were cultured and tested by qPCR. While 37 (6.4%) samples were positive for S. agalactiae by bacteriological culture, 66 (11.4%) samples were positive by qPCR. The within-herd prevalence in the six herds, as estimated by the latent class models ranged from 7.7 to 50.8%. At the recommended cut-off (cycle threshold 37), the sensitivity of the qPCR was significantly higher at 95.3 (95% posterior probability interval [PPI] [84.2; 99.6]) than that of bacteriological culture at 58.2 (95% PPI [43.8; 74.4]). However, bacterial culture had a higher specificity of 99.7 (95% PPI [98.5; 100.0]) compared to the qPCR at 98.5 (95% PPI [94.6; 99.9]). The median estimated negative predictive values of qPCR was consistently higher than those of the BC at all estimated prevalences, and the superiority of the qPCR increased with increasing within-herd prevalence. The median positive predictive values of BC was in general higher than the estimates for the qPCR, however, at the highest prevalence the predictive ability of both tests were similar. Copyright © 2018 Elsevier B.V. All

  10. Group B streptococcus activates transcriptomic pathways related to premature birth in human extraplacental membranes in vitro.

    Science.gov (United States)

    Park, Hae-Ryung; Harris, Sean M; Boldenow, Erica; McEachin, Richard C; Sartor, Maureen; Chames, Mark; Loch-Caruso, Rita

    2018-03-01

    Streptococcus agalactiae (group B streptococcus [GBS]) infection in pregnant women is the leading cause of infectious neonatal morbidity and mortality in the United States. Although inflammation during infection has been associated with preterm birth, the contribution of GBS to preterm birth is less certain. Moreover, the early mechanisms by which GBS interacts with the gestational tissue to affect adverse pregnancy outcomes are poorly understood. We hypothesized that short-term GBS inoculation activates pathways related to inflammation and premature birth in human extraplacental membranes. We tested this hypothesis using GBS-inoculated human extraplacental membranes in vitro. In agreement with our hypothesis, a microarray-based transcriptomics analysis of gene expression changes in GBS-inoculated membranes revealed that GBS activated pathways related to inflammation and preterm birth with significant gene expression changes occurring as early as 4 h postinoculation. In addition, pathways related to DNA replication and repair were downregulated with GBS treatment. Conclusions based on our transcriptomics data were further supported by responses of prostaglandin E2 (PGE2), and matrix metalloproteinases 1 (MMP1) and 3 (MMP3), all of which are known to be involved in parturition and premature rupture of membranes. These results support our initial hypothesis and provide new information on molecular targets of GBS infection in human extraplacental membranes.

  11. Cinética de fermentación y acción antimicrobiana de Weissella confusa contra Staphylococcus aureus y Streptococcus agalactiae

    Directory of Open Access Journals (Sweden)

    Liliana Serna Cock

    2010-01-01

    Full Text Available Se evaluaron las cinéticas de producción de biomasa, producción de ácido láctico, consumo de sustrato y actividad antimicrobiana de Weissella confusa, una bacteria acido láctica con actividad antimicrobiana frente a Streptococcus agalactiae y Staphylococcus aureus, microorganismos productores de mastitis bovina. Las fermentaciones se llevaron a cabo anaeróbicamente en discontinuo utilizando como sustratos, sustrato comercial (SC, leche suplementada con extracto levadura (LEL y leche suplementada con extracto de levadura y glucosa (LELG y se compararon los parámetros cinéticos. La mayor inhibición de los patógenos, la mayor producción de ácido láctico y el mayor rendimiento de biomasa se presentó en sustrato LELG. En éste último sustrato al cabo de la cuarta hora de fermentación, se presentó un diámetro de inhibición de 36,33 mm para Staphylococcus aureus y a la octava hora de fermentación 39 mm de diámetro para Streptococcus agalactiae; la producción máxima de ácido láctico fue 13,12 gL-1 (a las 48 h y la máxima concentración de biomasa fue 3,07 gL-1 (a las 48 h. Estos resultados fueron superiores a los obtenidos en SC donde, para el mismo tiempo de fermentación, se obtuvieron 24,38 mm para Staphylococcus aureus y 30,58 mm de diámetro de inhibición para Streptococcus agalactiae; la mayor producción de ácido láctico fue 11,6 gL-1 (a las 12 h y la mayor concentración de biomasa fue 1,18 gL-1 (a las 24 h. Los resultados sugieren que el LELG puede convertirse en una alternativa a bajo costo para la producción de Weissella confusa, microorganismo con gran potencial para el control y el tratamiento de mastitis bovina.

  12. Expression, purification, crystallization and preliminary X-ray diffraction studies of the human keratin 4-binding domain of serine-rich repeat protein 1 from Streptococcus agalactiae

    International Nuclear Information System (INIS)

    Sundaresan, Ramya; Samen, Ulrike; Ponnuraj, Karthe

    2011-01-01

    Expression, purification and crystallization of Srr-1-K4BD, a human keratin 4-binding domain of serine-rich repeat protein 1 from S. agalactiae, was carried out. Native crystals of Srr-1-K4BD diffracted to 3.8 Å resolution using synchrotron radiation. Serine-rich repeat protein 1 (Srr-1) is a surface protein from Streptococcus agalactiae. A 17 kDa region of this protein has been identified to bind to human keratin 4 (K4) and is termed the Srr-1 K4-binding domain (Srr-1-K4BD). Recombinant Srr-1-K4BD was overexpressed in Escherichia coli BL21 (DE3) cells. Native and selenomethionine-substituted proteins were prepared using Luria–Bertani (LB) and M9 minimal media, respectively. A two-step purification protocol was carried out to obtain a final homogenous sample of Srr-1-K4BD. Crystals of native Srr-1-K4BD were obtained using PEG 3350 as a precipitant. The crystals diffracted to 3.8 Å resolution using synchrotron radiation and belonged to space group P2 1 , with unit-cell parameters a = 47.56, b = 59.48, c = 94.71 Å, β = 93.95°

  13. In vitro antimicrobial activity of Combretum molle (Combretaceae) against Staphylococcus aureus and Streptococcus agalactiae isolated from crossbred dairy cows with clinical mastitis.

    Science.gov (United States)

    Regassa, Fekadu; Araya, Mengistu

    2012-08-01

    Following the rapidly expanding dairy enterprise, mastitis has remained the most economically damaging disease. The objective of this study was mainly to investigate the in vitro antibacterial activities of ethanol extracts of Combretum molle (R.Br.Ex.G.Don) Engl & Diels (Combretaceae) against antibiotic-resistant and susceptible Staphylococcus aureus and Streptococcus agalactiae isolated from clinical cases of bovine mastitis using agar disc diffusion method. The leaf and bark extracts showed antibacterial activity against S. aureus at concentrations of 3 mg/ml while the stem and seed extract did not show any bioactivity. Although both leaf and bark extracts were handled in the same manner, the antibacterial activity of the bark extract against the bacterial strains had declined gradually to a lower level as time advanced after extraction. The leaf extract had sustained bioactivity for longer duration. The susceptibility of the bacteria to the leaf extract is not obviously different between S. aureus and S. agalactiae. Also, there was no difference in susceptibility to the leaf extract between the antibiotic-resistant and antibiotic-sensitive bacteria. Further phytochemical and in vivo efficacy and safety studies are required to evaluate the therapeutic value of the plant against bovine mastitis.

  14. Estimation of test characteristics of real-time PCR and bacterial culture for diagnosis of subclinical intramammary infections with Streptococcus agalactiae in Danish dairy cattle in 2012 using latent class analysis.

    Science.gov (United States)

    Mahmmod, Yasser S; Toft, Nils; Katholm, Jørgen; Grønbæk, Carsten; Klaas, Ilka C

    2013-05-01

    The misdiagnosis of intramammary infections (IMI) with Streptococcus agalactiae (S. agalactiae) could lead farmers to treat or cull animals unnecessarily. The objective of this field study was to estimate the sensitivity (Se) and specificity (Sp) of real-time PCR at different cut-offs for cycle threshold (Ct) values against bacterial culture (BC) for diagnosis of S. agalactiae IMI using latent class analysis to avoid the assumption of a perfect reference test. A total of 614 dairy cows were randomly selected from 6 herds with bulk tank PCR Ct value ≤ 39 for S. agalactiae and S. aureus. At milk recording, 2456 quarter milk samples were taken aseptically for BC and the routinely taken cow level milk samples were analyzed by PCR. Results showed that 53 cows (8.6%) were positive for S. agalactiae IMI by BC. Sensitivity of PCR at cut-offs; ≤ 39, ≤ 37, ≤ 34, and ≤ 32, was 96.2%, 91.9%, 87.2% and 73.9%, while Se of BC was 25.7%, 29.9%, 59.9% and 72.1%. Specificity of PCR at cut-offs; ≤ 39, ≤ 37, ≤ 34, and ≤ 32, was 96.8%, 96.9%, 96.7%, and 97.22%, while Sp of BC was 99.7%, 99.5%, 99.2%, and 98.9%. The estimated prevalence of S. agalactiae IMI by PCR was higher than the apparent prevalence at the tested cut-offs, indicating under estimation of S. agalactiae IMI in the examined dairy cows. In conclusion, Se of PCR is always higher than Se of BC at all tested cut-offs. The lower cut-off, the more comparable becomes Se of PCR and Se of BC. The changes in Se in both PCR and BC at different Ct-value cut-offs may indicate a change in the definition of the latent infection. The similar Se of both tests at cut-off ≤ 32 may indicate high concentrations of S. agalactiae viable cells, representing a cow truly/heavily infected with S. agalactiae and thus easier to detect with BC. At cut-off ≤ 39 the latent definition of infection may reflect a more general condition of cows being positive for S. agalactiae. Our findings indicate that PCR Ct-value cut-offs should

  15. [Neonatal bacterial infection by maternal-fetal contamination: for a change in approach? 1. Detection of Streptococcus agalactiae infection: methods and evaluation of results].

    Science.gov (United States)

    Blond, M H; Gold, F; Pierre, F; Quentin, R; Aujard, Y

    2001-10-01

    Perinatal group B streptococcal infection has been the subject of numerous studies and despite guidelines established during the last decade remains a frequent disease with high mortality. The basic aim of the guidelines is to screen for Streptococcus agalactiae during the antepartum period in order to institute antibiotic therapy during delivery. A critical review of the literature highlights the real impact and adverse effect of these guidelines: difficult application (only two-thirds of all maternity units have a protocol and compliance is only 75%), maternal risks of antibiotic therapy (especially the emergence of resistant Gram negative bacteria), fetal risks (accentuation of neonatal sepsis with resistant strains, retarded neonatal infections, frequent use of antibiotics with a broader spectrum, higher frequency of nosocomial sepsis).

  16. The Effect of Decoction Leaves from Green Leaf (piper betle l. to Inhibition Activity of Streptococcus Agalactiae Cause of Mastitis in Dairy Cow

    Directory of Open Access Journals (Sweden)

    Oki Selfiana Marsono

    2017-07-01

    Full Text Available ABSTRACT This research was conducted from January to February 2017 at Microbiology Laboratory, Faculty Science and Technology, Islamic Maulana Maliki Ibrahim University, Malang and at Microbiology Laboratory, Faculty of Science, Muhammadiyah University, Malang. The purpose of this research was to determine the effectiveness of Piper betle L. leave extract on antibacterial activity the growth of Streptococcus agalactiae. The method used was Complete Randomized Design (CRD with 8 treatments and 6 replications. Piper betle L. leaves extract was used 20% for P0 (0-day, P1 (first day, P2 (second day, P3 (third day, P4 (fourth day, P5 (fiveth day, P6 (sixth days and P7 (seventh day. The results showed that Piper betle L. leaves extract had a highly significant effect (P<0.01 on inhibiting the growth of the bacteria so the results were continued with LSD test analysys because there were differences among variables. The results showed that P0 was the highest (3.93±0.50; then followed by P1 (3.83±0.69; P2 (3.47±0.21; P3 (3.13±0.22; P4 (3.12±0.58; P5 (3.04±0.24; P6 (3.00±0.44 include at medium categories, and P7 (2.97±0.19 include at low category, where inhibition zone which formed on each treatment have non significant decreased. In conclusion, the storage of Piper betle L. extract have effect on antibacterial activities (Streptococcus agalactiae, which the highest at day-0.

  17. Indirect enzyme-linked immunosorbent assay method based on Streptococcus agalactiae rSip-Pgk-FbsA fusion protein for detection of bovine mastitis.

    Science.gov (United States)

    Bu, Ri-E; Wang, Jin-Liang; Wu, Jin-Hua; Xilin, Gao-Wa; Chen, Jin-Long; Wang, Hua

    2017-03-01

    The aim of this study was to establish a rapid and accurate method for the detection of the Streptococcus agalactiae antibody (SA-Ab) to determine the presence of the bovine mastitis (BM)-causative pathogen. The multi-subunit fusion protein rSip-Pgk-FbsA was prokaryotically expressed and purified. The triple activities of the membrane surface-associated proteins Sip, phosphoglycerate kinase (Pgk), and fibronectin (FbsA) were used as the diagnostic antigens to establish an indirect enzyme-linked immunosorbent assay (ELISA) method for the detection of SA-Ab in BM. The optimal antigen coating concentration was 2 μg/mL, the optimal serum dilution was 1:160, and the optimal dilution of the enzyme-labeled secondary antibody was 1:6000. The sensitivity, specificity, and repeatability tests showed that the method established in this study had no cross-reaction with antibodies to Streptococcus pyogenes, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis in the sera. The results of the sensitivity test showed that a positive result could be obtained even if the serum dilution reached 1:12,800, indicating the high sensitivity and good repeatability of the method. The positive coincidence rate of this method was 98.6%, which is higher than that of previous tests established with the Sip or Pgk mono-antigen fusion protein, respectively, demonstrating the relatively higher sensitivity of this newly established method. The detection rate for 389 clinical samples was 46.53%. The indirect ELISA method established in this study could provide a more accurate and reliable serological method for the rapid detection of S. agalactiae in cases of BM.

  18. An homolog of the Frz Phosphoenolpyruvate:carbohydrate phosphoTransferase System of extraintestinal pathogenic Escherichia coli is encoded on a genomic island in specific lineages of Streptococcus agalactiae.

    Science.gov (United States)

    Patron, Kévin; Gilot, Philippe; Camiade, Emilie; Mereghetti, Laurent

    2015-06-01

    We identified a Streptococcus agalactiae metabolic region (fru2) coding for a Phosphoenolpyruvate:carbohydrate phosphoTransferase System (PTS) homologous to the Frz system of extraintestinal pathogenic Escherichia coli strains. The Frz system is involved in environmental sensing and regulation of the expression of adaptation and virulence genes in E. coli. The S. agalactiae fru2 region codes three subunits of a PTS transporter of the fructose-mannitol family, a transcriptional activator of PTSs of the MtlR family, an allulose-6 phosphate-3-epimerase, a transaldolase and a transketolase. We demonstrated that all these genes form an operon. The fru2 operon is present in a 17494-bp genomic island. We analyzed by multilocus sequence typing a population of 492 strains representative of the S. agalactiae population and we showed that the presence of the fru2 operon is linked to the phylogeny of S. agalactiae. The fru2 operon is always present within strains of clonal complexes CC 1, CC 7, CC 10, CC 283 and singletons ST 130 and ST 288, but never found in other CCs and STs. Our results indicate that the fru2 operon was acquired during the evolution of the S. agalactiae species from a common ancestor before the divergence of CC 1, CC 7, CC 10, CC 283, ST 130 and ST 288. As S. agalactiae strains of CC 1 and CC 10 are frequently isolated from adults with invasive disease, we hypothesize that the S. agalactiae Fru2 system senses the environment to allow the bacterium to adapt to new conditions encountered during the infection of adults. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Purinergic signaling modulates the cerebral inflammatory response in experimentally infected fish with Streptococcus agalactiae: an attempt to improve the immune response.

    Science.gov (United States)

    Souza, Carine F; Baldissera, Matheus D; Bottari, Nathiele B; Moreira, Karen L S; da Rocha, Maria Izabel U M; da Veiga, Marcelo L; Santos, Roberto C V; Baldisserotto, Bernardo

    2018-06-01

    Appropriate control of the immune response is a critical determinant of fish health, and the purinergic cascade has an important role in the immune and inflammatory responses. This cascade regulates the levels of adenosine triphosphate (ATP), adenosine diphosphate, adenosine monophosphate and adenosine (Ado), molecules involved in physiological or pathological events as inflammatory and anti-inflammatory mediators. Thus, the aim of this study was to evaluate whether purinergic signaling, through the activities of nucleoside triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase, and adenosine deaminase (ADA), is capable of modulating the cerebral immune and inflammatory responses in silver catfish that is experimentally infected with Streptococcus agalactiae. Cerebral NTPDase (with ATP as substrate) and 5'-nucleotidase activities increased, while ADA activity decreased in silver catfish that is experimentally infected with S. agalactiae, compared to the control group. Moreover, the cerebral levels of ATP and Ado increased in infected animals compared to the uninfected control group. Brain histopathology in infected animals revealed inflammatory demyelination (the presence of occasional bubbly collections), increased cellular density in the area near to pia-mater and intercellular edema. Based on this evidence, the modulation of the purinergic cascade by the enzymes NTPDase, 5'-nucleotidase, and ADA exerts an anti-inflammatory profile due to the regulation of ATP and Ado levels. This suggests involvement of purinergic enzymes on streptococcosis pathogenesis, through regulating cerebral ATP and Ado levels, molecules known to participate in physiological or pathological events as inflammatory and anti-inflammatory mediators, respectively. In summary, the modulation of the cerebral purinergic cascade exerts an anti-inflammatory profile in an attempt to reduce inflammatory damage.

  20. Analysis of the type II-A CRISPR-Cas system of Streptococcus agalactiae reveals distinctive features according to genetic lineages

    Science.gov (United States)

    Lier, Clément; Baticle, Elodie; Horvath, Philippe; Haguenoer, Eve; Valentin, Anne-Sophie; Glaser, Philippe; Mereghetti, Laurent; Lanotte, Philippe

    2015-01-01

    CRISPR-Cas systems (clustered regularly interspaced short palindromic repeats/CRISPR-associated proteins) are found in 90% of archaea and about 40% of bacteria. In this original system, CRISPR arrays comprise short, almost unique sequences called spacers that are interspersed with conserved palindromic repeats. These systems play a role in adaptive immunity and participate to fight non-self DNA such as integrative and conjugative elements, plasmids, and phages. In Streptococcus agalactiae, a bacterium implicated in colonization and infections in humans since the 1960s, two CRISPR-Cas systems have been described. A type II-A system, characterized by proteins Cas9, Cas1, Cas2, and Csn2, is ubiquitous, and a type I–C system, with the Cas8c signature protein, is present in about 20% of the isolates. Unlike type I–C, which appears to be non-functional, type II-A appears fully functional. Here we studied type II-A CRISPR-cas loci from 126 human isolates of S. agalactiae belonging to different clonal complexes that represent the diversity of the species and that have been implicated in colonization or infection. The CRISPR-cas locus was analyzed both at spacer and repeat levels. Major distinctive features were identified according to the phylogenetic lineages previously defined by multilocus sequence typing, especially for the sequence type (ST) 17, which is considered hypervirulent. Among other idiosyncrasies, ST-17 shows a significantly lower number of spacers in comparison with other lineages. This characteristic could reflect the peculiar virulence or colonization specificities of this lineage. PMID:26124774

  1. Survey of strain distribution and antibiotic resistance pattern of group B streptococci (Streptococcus agalactiae isolated from clinical specimens

    Directory of Open Access Journals (Sweden)

    Mousavi, Seyed Masoud

    2016-09-01

    Full Text Available Aim: The aims of the present study were to determine the antibiotic susceptibility profils with particular emphasis on susceptible or resistant strains to macrolides and lincosamids antibiotics and to determine possible antibiotic resistance mechanisms occurring in group B streptococci (GBS strains using PCR assay and disk diffusion method.Methods: A total of 62 clinical GBS strains were investigated. Antibacterial susceptibility testing was performed using the disk diffusion method and inducible resistance test for clindamycin by standard double disk diffusion or D-zone test for all isolates to differentiate macrolide resistance phenotype (M, constitutive macrolide-lincosamide-streptogramin B phenotype (cMLS and induced macrolide-lincosamide-streptogramin B phenotype (iMLS. In addition, minimum inhibitory concentrations (MIC of penicillin were determined for all isolates. Finally, possible existence of antibiotic resistance genes for erythromycin , and and for clindamycin were examined among isolates using PCR assay.Results: All 62 isolates were susceptible to penicillin, ampicillin, linezolid, cefazoline and vancomycin. However, 93.5% (n=58 of isolates showed an increased MIC to penicillin. The overall rate of erythromycin resistance was 35.5% (n=22. All erythromycin-resistant isolates displayed the M phenotype (100%, n=22. All three erythromycin resistance genes (i.e. , and were found in erythromycin-resistant isolates.Conclusion: It was concluded that prescribing antibiotic without antibacterial susceptibility tests should be prevented because of the high prevalence of erythromycin-resistant GBS strains and the fact that erythromycin-resistant GBS strains has shown an increased MIC to penicillin, as the drug of choice for treating GBS infections.

  2. Influencia de la composici??n del medio de cultivo sobre la producci??n de pigmento por Streptococcus agalactiae

    OpenAIRE

    Carazo Carazo, Concepci??n

    1995-01-01

    Se ha estudiado la influencia de la composici??n del medio de cultivo sobre la producci??n de pigmento por s. agalactiae partiendo de un medio de cultivo dise??ado para tal finalidad (new granada medium), eliminando uno a uno los componentes incluidos en su formulaci??n original. Almid??n, proteosa peptona (difco), suero, fosfatos y metrotexato influyen de forma importante en la formaci??n y/o visualizaci??n del pigmento producido por este microorganismo. Se ha determinado que la fracci??n de...

  3. Effect Of Gamma Ray Irradiation On Streptococcus Agalactiae Growth For Vaccine Agent Of Mastitis Disease In Dairy Cattle

    International Nuclear Information System (INIS)

    Jeane Tuasikal, B; Sugoro, I; Tjiptosumirat, T; Lina, M

    2003-01-01

    A study has been conducted to determine the effect of gamma ray irradiation to attenuate infectivity of S. agalactiae as dominant bacteria causing mastitis in dairy cattle. The aim of the study is obtaining optimum irradiation dosage to provide radio vaccine for mastitis. S. agalactiae isolate bacteria of which has reach the mid log-phase was cultured and divided into 6 treatment groups of irradiation doses, i.e. 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Following irradiation, bacteria were then cultured in BHI agar media for colony counting to determine the LD 50 , resulting 7.5x10 8 ; 5.0x10 7 ; 7.0x10 6 ; 9.5x10 5 ; 1.5x10 4 ; and 3.5x10 3 cell/ml, respectively. Result of this study shows the higher irradiation doses the lower number of bacteria per ml, and LD 50 , which found to be under 0.2 kGy of irradiation dose

  4. Prevalence of Streptococcus agalactiae colonization in pregnant women from the 18th Health Region of Paraná State

    Directory of Open Access Journals (Sweden)

    Simone Cristina Castanho Sabaini de Melo

    2018-02-01

    Full Text Available ABSTRACT Introduction The aim of this study was to determine the prevalence of GBS colonization in pregnant women in a public health service. Methods A study of 496 pregnant women at 35-37 gestational weeks was conducted from September 2011 to March 2014 in 21 municipalities of the 18th Health Region of Paraná State. Vaginal and anorectal samples of each woman were plated on sheep blood agar, and in HPTH and Todd-Hewitt enrichment broths. Results Of the 496 pregnant women, 141 (28.4% were positive for GBS based on the combination of the three culture media with vaginal and anorectal samples. The prevalence was 23.7% for vaginal samples and 21.9% for anorectal ones. Among the variables analyzed in this study, only urinary infection was a significant factor (0.026 associated with GBS colonization in women. Conclusions Based on these results, health units should performs universal screening of pregnant women and hospitals should provide adequate prophylaxis, when indicated.

  5. RNA-Seq revealed the impairment of immune defence of tilapia against the infection of Streptococcus agalactiae with simulated climate warming.

    Science.gov (United States)

    Wang, Le; Liu, Peng; Wan, Zi Yi; Huang, Shu Qing; Wen, Yan Fei; Lin, Grace; Yue, Gen Hua

    2016-08-01

    Global warming is one of the causes of disease outbreaks in fishes. Understanding its mechanisms is critical in aquaculture and fisheries. We used tilapia to study the effects of a high temperature on the infection of a bacterial pathogen Streptococcus agalactiae using RNA-Seq. We found that the dissolved oxygen level in water at 32 °C is lower than at 22 °C, and tilapia infected with the pathogen died more rapidly at 32 °C. The gene expression profiles showed significant differences in fish raised under different conditions. We identified 126 and 576 differentially expressed genes (DEGs) at 4 and 24 h post infection at 22 °C, respectively, whereas at 32 °C, the data were 312 and 1670, respectively. Almost all responding pathways at 22 °C were involved in the immune responses, whereas at 32 °C, the enriched pathways were not only involved in immune responses but also involved in oxygen and energy metabolisms. We identified significant signals of immunosuppression of immune responses at 32 °C. In addition, many of the enriched transcription factors and DEGs under positive selection were involved in immune responses, oxygen and/or energy metabolisms. Our results suggest that global warming could reduce the oxygen level in water and impair the defence of tilapia against bacterial infection. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Evidence for Rare Capsular Switching in Streptococcus agalactiae▿

    Science.gov (United States)

    Martins, Elisabete Raquel; Melo-Cristino, José; Ramirez, Mário

    2010-01-01

    The polysaccharide capsule is a major antigenic factor in Streptococcus agalactiae (Lancefield group B streptococcus [GBS]). Previous observations suggest that exchange of capsular loci is likely to occur rather frequently in GBS, even though GBS is not known to be naturally transformable. We sought to identify and characterize putative capsular switching events, by means of a combination of phenotypic and genotypic methods, including pulsed-field gel electrophoretic profiling, multilocus sequence typing, and surface protein and pilus gene profiling. We show that capsular switching by horizontal gene transfer is not as frequent as previously suggested. Serotyping errors may be the main reason behind the overestimation of capsule switching, since phenotypic techniques are prone to errors of interpretation. The identified putative capsular transformants involved the acquisition of the entire capsular locus and were not restricted to the serotype-specific central genes, the previously suggested main mechanism underlying capsular switching. Our data, while questioning the frequency of capsular switching, provide clear evidence for in vivo capsular transformation in S. agalactiae, which may be of critical importance in planning future vaccination strategies against this pathogen. PMID:20023016

  7. Characterization of a new CAMP factor carried by an integrative and conjugative element in Streptococcus agalactiae and spreading in Streptococci.

    Directory of Open Access Journals (Sweden)

    Sarah Chuzeville

    Full Text Available Genetic exchanges between Streptococci occur frequently and contribute to their genome diversification. Most of sequenced streptococcal genomes carry multiple mobile genetic elements including Integrative and Conjugative Elements (ICEs that play a major role in these horizontal gene transfers. In addition to genes involved in their mobility and regulation, ICEs also carry genes that can confer selective advantages to bacteria. Numerous elements have been described in S. agalactiae especially those integrated at the 3' end of a tRNA(Lys encoding gene. In strain 515 of S. agalactiae, an invasive neonate human pathogen, the ICE (called 515_tRNA(Lys is functional and carries different putative virulence genes including one encoding a putative new CAMP factor in addition to the one previously described. This work demonstrated the functionality of this CAMP factor (CAMP factor II in Lactococcus lactis but also in pathogenic strains of veterinary origin. The search for co-hemolytic factors in a collection of field strains revealed their presence in S. uberis, S. dysgalactiae, but also for the first time in S. equisimilis and S. bovis. Sequencing of these genes revealed the prevalence of a species-specific factor in S. uberis strains (Uberis factor and the presence of a CAMP factor II encoding gene in S. bovis and S. equisimilis. Furthermore, most of the CAMP factor II positive strains also carried an element integrated in the tRNA(Lys gene. This work thus describes a CAMP factor that is carried by a mobile genetic element and has spread to different streptococcal species.

  8. β-Hemolysin/cytolysin of Group B Streptococcus enhances host inflammation but is dispensable for establishment of urinary tract infection.

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    Ritwij Kulkarni

    Full Text Available Group B Streptococcus (GBS; Streptococcus agalactiae is a major human pathogen that disproportionately affects neonates and women in the peripartum period and is an emerging cause of infection in older adults. The primary toxin of GBS, β-hemolysin/cytolysin (βH/C, has a well-defined role in the pathogenesis of invasive disease, but its role in urinary tract infection (UTI is unknown. Using both in vitro and in vivo models, we analyzed the importance of βH/C in GBS uropathogenesis. There were no significant differences in bacterial density from the bladders or kidneys from mice infected with wild-type or isogenic βH/C-deficient GBS, and competitive indices from co-infection experiments were near 1. Thus, βH/C is dispensable for the establishment of GBS-UTI. However, βH/C-sufficient GBS induced a more robust proinflammatory cytokine response in cultured bladder epithelial cells and in the urinary tracts of infected mice. Given the near ubiquity of βH/C-expressing strains in epidemiologic studies and the importance of local inflammation in dictating outcomes and sequelae of UTI, we hypothesize that βH/C-driven inflammatory signaling may be important in the clinical course of GBS-UTI.

  9. Macrolide resistance gene erm(TR) and erm(TR)-carrying genetic elements in Streptococcus agalactiae: characterization of ICESagTR7, a new composite element containing IMESp2907.

    Science.gov (United States)

    Mingoia, Marina; Morici, Eleonora; Marini, Emanuela; Brenciani, Andrea; Giovanetti, Eleonora; Varaldo, Pietro E

    2016-03-01

    The objective of this study was to investigate macrolide-resistant Streptococcus agalactiae isolates harbouring erm(TR), an erm(A) gene subclass, with emphasis on their erm(TR)-carrying genetic elements. Four erm(TR)-carrying elements have been described to date: three closely related (ICE10750-RD.2, Tn1806 and ICESp1108) in Streptococcus pyogenes, Streptococcus pneumoniae and S. pyogenes, respectively; and one completely different (IMESp2907, embedded in ICESp2906 to form ICESp2905) in S. pyogenes. Seventeen macrolide-resistant erm(TR)-positive S. agalactiae isolates were phenotypically and genotypically characterized. Their erm(TR)-carrying elements were explored by analysing the distinctive recombination genes of known erm(TR)-carrying integrative and conjugative elements (ICEs) and by PCR mapping. The new genetic context and organization of IMESp2907 in S. agalactiae were explored using several experimental procedures and in silico analyses. Five isolates harboured ICE10750-RD.2/Tn1806, five isolates harboured ICESp1108 and five isolates bore unknown erm(TR)-carrying elements. The remaining two isolates, exhibiting identical serotypes and pulsotypes, harboured IMESp2907 in a new genetic environment, which was further investigated in one of the two isolates, SagTR7. IMESp2907 was circularizable in S. agalactiae, as described in S. pyogenes. The new IMESp2907 junctions were identified based on its site-specific integration; the att sites were almost identical to those in S. pyogenes. In strain SagTR7, erm(TR)-carrying IMESp2907 was embedded in an erm(TR)-less internal element related to ICE10750-RD.2/Tn1806, which, in turn, was embedded in an ICESde3396-like element. The resulting whole ICE, ICESagTR7 (∼129 kb), was integrated into the chromosome downstream of the rplL gene, and was excisable in circular form and transferable by conjugation. This is the first study exploring erm(TR)-carrying genetic elements in S. agalactiae. © The Author 2015. Published by

  10. Group B Streptococcus Induces Neutrophil Recruitment to Gestational Tissues and Elaboration of Extracellular Traps and Nutritional Immunity

    Science.gov (United States)

    Kothary, Vishesh; Doster, Ryan S.; Rogers, Lisa M.; Kirk, Leslie A.; Boyd, Kelli L.; Romano-Keeler, Joann; Haley, Kathryn P.; Manning, Shannon D.; Aronoff, David M.; Gaddy, Jennifer A.

    2017-01-01

    Streptococcus agalactiae, or Group B Streptococcus (GBS), is a gram-positive bacterial pathogen associated with infection during pregnancy and is a major cause of morbidity and mortality in neonates. Infection of the extraplacental membranes surrounding the developing fetus, a condition known as chorioamnionitis, is characterized histopathologically by profound infiltration of polymorphonuclear cells (PMNs, neutrophils) and greatly increases the risk for preterm labor, stillbirth, or neonatal GBS infection. The advent of animal models of chorioamnionitis provides a powerful tool to study host-pathogen relationships in vivo and ex vivo. The purpose of this study was to evaluate the innate immune response elicited by GBS and evaluate how antimicrobial strategies elaborated by these innate immune cells affect bacteria. Our work using a mouse model of GBS ascending vaginal infection during pregnancy reveals that clinically isolated GBS has the capacity to invade reproductive tissues and elicit host immune responses including infiltration of PMNs within the choriodecidua and placenta during infection, mirroring the human condition. Upon interacting with GBS, murine neutrophils elaborate DNA-containing extracellular traps, which immobilize GBS and are studded with antimicrobial molecules including lactoferrin. Exposure of GBS to holo- or apo-forms of lactoferrin reveals that the iron-sequestration activity of lactoferrin represses GBS growth and viability in a dose-dependent manner. Together, these data indicate that the mouse model of ascending infection is a useful tool to recapitulate human models of GBS infection during pregnancy. Furthermore, this work reveals that neutrophil extracellular traps ensnare GBS and repress bacterial growth via deposition of antimicrobial molecules, which drive nutritional immunity via metal sequestration strategies. PMID:28217556

  11. Group B Streptococcus Induces Neutrophil Recruitment to Gestational Tissues and Elaboration of Extracellular Traps and Nutritional Immunity.

    Science.gov (United States)

    Kothary, Vishesh; Doster, Ryan S; Rogers, Lisa M; Kirk, Leslie A; Boyd, Kelli L; Romano-Keeler, Joann; Haley, Kathryn P; Manning, Shannon D; Aronoff, David M; Gaddy, Jennifer A

    2017-01-01

    Streptococcus agalactiae , or Group B Streptococcus (GBS), is a gram-positive bacterial pathogen associated with infection during pregnancy and is a major cause of morbidity and mortality in neonates. Infection of the extraplacental membranes surrounding the developing fetus, a condition known as chorioamnionitis, is characterized histopathologically by profound infiltration of polymorphonuclear cells (PMNs, neutrophils) and greatly increases the risk for preterm labor, stillbirth, or neonatal GBS infection. The advent of animal models of chorioamnionitis provides a powerful tool to study host-pathogen relationships in vivo and ex vivo . The purpose of this study was to evaluate the innate immune response elicited by GBS and evaluate how antimicrobial strategies elaborated by these innate immune cells affect bacteria. Our work using a mouse model of GBS ascending vaginal infection during pregnancy reveals that clinically isolated GBS has the capacity to invade reproductive tissues and elicit host immune responses including infiltration of PMNs within the choriodecidua and placenta during infection, mirroring the human condition. Upon interacting with GBS, murine neutrophils elaborate DNA-containing extracellular traps, which immobilize GBS and are studded with antimicrobial molecules including lactoferrin. Exposure of GBS to holo- or apo-forms of lactoferrin reveals that the iron-sequestration activity of lactoferrin represses GBS growth and viability in a dose-dependent manner. Together, these data indicate that the mouse model of ascending infection is a useful tool to recapitulate human models of GBS infection during pregnancy. Furthermore, this work reveals that neutrophil extracellular traps ensnare GBS and repress bacterial growth via deposition of antimicrobial molecules, which drive nutritional immunity via metal sequestration strategies.

  12. The surface protein HvgA mediates group B streptococcus hypervirulence and meningeal tropism in neonates.

    Science.gov (United States)

    Tazi, Asmaa; Disson, Olivier; Bellais, Samuel; Bouaboud, Abdelouhab; Dmytruk, Nicolas; Dramsi, Shaynoor; Mistou, Michel-Yves; Khun, Huot; Mechler, Charlotte; Tardieux, Isabelle; Trieu-Cuot, Patrick; Lecuit, Marc; Poyart, Claire

    2010-10-25

    Streptococcus agalactiae (group B streptococcus; GBS) is a normal constituent of the intestinal microflora and the major cause of human neonatal meningitis. A single clone, GBS ST-17, is strongly associated with a deadly form of the infection called late-onset disease (LOD), which is characterized by meningitis in infants after the first week of life. The pathophysiology of LOD remains poorly understood, but our epidemiological and histopathological results point to an oral route of infection. Here, we identify a novel ST-17-specific surface-anchored protein that we call hypervirulent GBS adhesin (HvgA), and demonstrate that its expression is required for GBS hypervirulence. GBS strains that express HvgA adhered more efficiently to intestinal epithelial cells, choroid plexus epithelial cells, and microvascular endothelial cells that constitute the blood-brain barrier (BBB), than did strains that do not express HvgA. Heterologous expression of HvgA in nonadhesive bacteria conferred the ability to adhere to intestinal barrier and BBB-constituting cells. In orally inoculated mice, HvgA was required for intestinal colonization and translocation across the intestinal barrier and the BBB, leading to meningitis. In conclusion, HvgA is a critical virulence trait of GBS in the neonatal context and stands as a promising target for the development of novel diagnostic and antibacterial strategies.

  13. The effects of dietary kefir and low molecular weight sodium alginate on serum immune parameters, resistance against Streptococcus agalactiae and growth performance in Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Van Doan, Hien; Hoseinifar, Seyed Hossein; Tapingkae, Wanaporn; Khamtavee, Pimporn

    2017-03-01

    The present study evaluates the effects of dietary kefir and low molecular weight sodium alginate (LWMSA) (singular or combined) on non-specific immune response, disease resistance and growth performance of Nile tilapia (Oreochromis niloticus). Fish with average weight of 18.60 ± 0.04 g were supplied and randomly stocked in sixteen glass tanks (150 L) at density of 20 fish per tank. Fish were fed experimental diets as follows: 0 g kg -1 LMWSA (Control, Diet 1), 10 g kg -1 LMWSA (Diet 2), 40 g kg -1 kefir (Diet 3), and 10 g kg -1 LMWSA + 40 g kg -1 kefir (Diet 4) for 50 days. At the end of the feeding trial, serum lysozyme (SL), phagocytosis (PI), respiratory burst (RB), and alternative complement (ACH50) activities as well as growth performance were measured. Singular and combined administration of kefir and low molecular weight sodium alginate (LMWSA) significantly increased serum SL, PI, RB, and ACH50 activities compared control group (P < 0.05); the highest innate immune responses were observed in fish fed combinational diet (kefir + LMWSA) (P < 0.05). The results of experimental challenge revealed significantly higher resistance against Streptococcus agalactiae in fish fed supplemented diets and the highest post challenge survival rate was observed in synbiotic diet (P < 0.05). Similar results obtained in case of growth parameters. Feeding on supplemented diet significantly improved SGR and FCR and the highest growth parameters was observed in fish fed synbiotic diet (P < 0.05). These finding revealed that combined administration of dietary kefir and LMWSA can be considered for improving immune response, disease resistance and growth performance of Nile tilapia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Group B streptococcus - pregnancy

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000511.htm Group B streptococcus - pregnancy To use the sharing features on this page, please enable JavaScript. Group B streptococcus (GBS) is a type of bacteria that some ...

  15. Characterization of Isolates of Streptococcus agalactiae from Diseased Farmed and Wild Marine Fish from the U.S. Gulf Coast, Latin America, and Thailand.

    Science.gov (United States)

    Soto, Esteban; Wang, Rui; Wiles, Judy; Baumgartner, Wes; Green, Christopher; Plumb, John; Hawke, John

    2015-06-01

    We examined Lancefield serogroup B Streptococcus isolates recovered from diseased, cultured hybrid Striped Bass (Striped Bass Morone saxatilis × White Bass M. chrysops) and wild and cultured Gulf Killifish Fundulus grandis from coastal waters of the U.S. Gulf of Mexico (Gulf coast) and compared those isolates to strains from tilapias Oreochromis spp. reared in Mississippi, Thailand, Ecuador, and Honduras and to the original Gulf coast strain identified by Plumb et al. ( 1974 ). The isolates were subjected to phylogenetic, biochemical, and antibiotic susceptibility analyses. Genetic analysis was performed using partial sequence comparison of (1) the 16S ribosomal RNA (rRNA) gene; (2) the sipA gene, which encodes a surface immunogenic protein; (3) the cspA gene, which encodes a cell surface-associated protein; and (4) the secY gene, which encodes components of a general protein secretion pathway. Phylogenies inferred from sipA, secY, and cspA gene sequence comparisons were more discriminating than that inferred from the 16S rRNA gene sequence comparison. The U.S. Gulf coast strains showed a high degree of similarity to strains from South America and Central America and belonged to a unique group that can be distinguished from other group B streptococci. In agreement with the molecular findings, biochemical and antimicrobial resistance analyses demonstrated that the isolates recovered from the U.S. Gulf coast and Latin America were more similar to each other than to isolates from Thailand. Three laboratory challenge methods for inducing streptococcosis in Gulf Killifish were evaluated-intraperitoneal (IP) injection, immersion (IMM), and immersion plus abrasion (IMMA)-using serial dilutions of S. agalactiae isolate LADL 97-151, a representative U.S. Gulf coast strain. The dose that was lethal to 50% of test fish by 14 d postchallenge was approximately 2 CFU/fish via IP injection. In contrast, the fish that were challenged via IMM or IMMA presented cumulative mortality

  16. Prevalência de colonização por Streptococcus agalactiae em gestantes atendidas em maternidade do Ceará, no Brasil, correlacionando com os resultados perinatais Prevalence of the colonization by Streptococcus agalactiae in pregnant women from a maternity in Ceará, Brazil, correlating with perinatal outcomes

    Directory of Open Access Journals (Sweden)

    José Juvenal Linhares

    2011-12-01

    Full Text Available OBJETIVO: Analisar a prevalência de Streptococcus agalactiae, um estreptococo do Grupo B, em gestantes e seus possíveis fatores de risco, bem como o impacto perinatal e a suscetibilidade antimicrobiana das colonizadas. MÉTODOS: Foram avaliadas 213 gestantes a partir de 20 semanas de gestação, independente dos fatores de risco, atendidas em um hospital-escola terciário da zona Norte do Estado de Ceará, no Brasil. O cálculo do tamanho amostral ocorreu por conveniência. Foi utilizada técnica do swab estéril único para coleta de secreção das regiões vaginal e perianal. As amostras recém-obtidas eram armazenadas em meio de transporte Stuart e, no laboratório, inoculadas em meio seletivo Todd-Hewitt adicionado de gentamicina (8 ug/mL e ácido nalidíxico (15 ug/mL, com posterior subcultivo em placas em ágar-sangue. Nos materiais eram realizados teste de Gram, catalase com peróxido de oxigênio e CAMP (Christie, Atkins, Munch-Petersen, sendo confirmados sorologicamente com Streptococcal Grouping Kit, Oxoid®. As positivas foram submetidas a testes de suscetibilidade antimicrobiana. Foram também avaliadas variáveis socioeconômicas, reprodutivas, clínico-obstétricas e neonatais. Os dados foram analisados utilizando o programa Epi-Info 6.04. RESULTADOS: A prevalência de colonização encontrada foi de 9,8% pelo teste de CAMP, embora apenas 4,2% pelo sorológico. O único fator de proteção observado foi cor da pele branca (p=0,01, 0.45>OR>0.94, IC95%. Não foi observada diferença de prevalência do estreptococo do Grupo B com outras variáveis reprodutivas ou obstétricas. Ocorreu infecção em apenas um dos recém-nascidos de mães colonizadas, entretanto revelou-se infecção por Pseudomonas spp. Foi encontrada resistência para ampicilina (4/9 e cefalotina (4/9, penicilina (4/9 casos, eritromicina (3/9, clindamicina (7/9 e cloranfenicol (1/9. CONCLUSÕES: A taxa de infecção foi inferior à encontrada em outros estudos

  17. Spatiotemporal patterns, annual baseline and movement-related incidence of Streptococcus agalactiae infection in Danish dairy herds: 2000–2009

    DEFF Research Database (Denmark)

    Mweu, Marshal M.; Nielsen, Søren S.; Hisham Beshara Halasa, Tariq

    2014-01-01

    -herd sources of new herd infections coupled with the spatiotemporal distribution of the infection, may aid in effective targeting of control efforts. Thus, the objectives of this study were: (1) to describe the spatiotemporal patterns of infection with S. agalactiae in the population of Danish dairy herds from...

  18. Transcriptome adaptation of group B Streptococcus to growth in human amniotic fluid.

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    Izabela Sitkiewicz

    Full Text Available BACKGROUND: Streptococcus agalactiae (group B Streptococcus is a bacterial pathogen that causes severe intrauterine infections leading to fetal morbidity and mortality. The pathogenesis of GBS infection in this environment is poorly understood, in part because we lack a detailed understanding of the adaptation of this pathogen to growth in amniotic fluid. To address this knowledge deficit, we characterized the transcriptome of GBS grown in human amniotic fluid (AF and compared it with the transcriptome in rich laboratory medium. METHODS: GBS was grown in Todd Hewitt-yeast extract medium and human AF. Bacteria were collected at mid-logarithmic, late-logarithmic and stationary growth phase. We performed global expression microarray analysis using a custom-made Affymetrix GeneChip. The normalized hybridization values derived from three biological replicates at each growth point were obtained. AF/THY transcript ratios representing greater than a 2-fold change and P-value exceeding 0.05 were considered to be statistically significant. PRINCIPAL FINDINGS: We have discovered that GBS significantly remodels its transcriptome in response to exposure to human amniotic fluid. GBS grew rapidly in human AF and did not exhibit a global stress response. The majority of changes in GBS transcripts in AF compared to THY medium were related to genes mediating metabolism of amino acids, carbohydrates, and nucleotides. The majority of the observed changes in transcripts affects genes involved in basic bacterial metabolism and is connected to AF composition and nutritional requirements of the bacterium. Importantly, the response to growth in human AF included significant changes in transcripts of multiple virulence genes such as adhesins, capsule, and hemolysin and IL-8 proteinase what might have consequences for the outcome of host-pathogen interactions. CONCLUSIONS/SIGNIFICANCE: Our work provides extensive new information about how the transcriptome of GBS responds

  19. Genomic analysis reveals the molecular basis for capsule loss in the group B Streptococcus population.

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    Roberto Rosini

    Full Text Available The human and bovine bacterial pathogen Streptococcus agalactiae (Group B Streptococcus, GBS expresses a thick polysaccharide capsule that constitutes a major virulence factor and vaccine target. GBS can be classified into ten distinct serotypes differing in the chemical composition of their capsular polysaccharide. However, non-typeable strains that do not react with anti-capsular sera are frequently isolated from colonized and infected humans and cattle. To gain a comprehensive insight into the molecular basis for the loss of capsule expression in GBS, a collection of well-characterized non-typeable strains was investigated by genome sequencing. Genome based phylogenetic analysis extended to a wide population of sequenced strains confirmed the recently observed high clonality among GBS lineages mainly containing human strains, and revealed a much higher degree of diversity in the bovine population. Remarkably, non-typeable strains were equally distributed in all lineages. A number of distinct mutations in the cps operon were identified that were apparently responsible for inactivation of capsule synthesis. The most frequent genetic alterations were point mutations leading to stop codons in the cps genes, and the main target was found to be cpsE encoding the portal glycosyl transferase of capsule biosynthesis. Complementation of strains carrying missense mutations in cpsE with a wild-type gene restored capsule expression allowing the identification of amino acid residues essential for enzyme activity.

  20. Comparison of different sampling techniques and of different culture methods for detection of group B streptococcus carriage in pregnant women

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    Verhelst Rita

    2010-09-01

    Full Text Available Abstract Background Streptococcus agalactiae (group B streptococcus; GBS is a significant cause of perinatal and neonatal infections worldwide. To detect GBS colonization in pregnant women, the CDC recommends isolation of the bacterium from vaginal and anorectal swab samples by growth in a selective enrichment medium, such as Lim broth (Todd-Hewitt broth supplemented with selective antibiotics, followed by subculture on sheep blood agar. However, this procedure may require 48 h to complete. We compared different sampling and culture techniques for the detection of GBS. Methods A total of 300 swabs was taken from 100 pregnant women at 35-37 weeks of gestation. For each subject, one rectovaginal, one vaginal and one rectal ESwab were collected. Plating onto Columbia CNA agar (CNA, group B streptococcus differential agar (GBSDA (Granada Medium and chromID Strepto B agar (CA, with and without Lim broth enrichment, were compared. The isolates were confirmed as S. agalactiae using the CAMP test on blood agar and by molecular identification with tDNA-PCR or by 16S rRNA gene sequence determination. Results The overall GBS colonization rate was 22%. GBS positivity for rectovaginal sampling (100% was significantly higher than detection on the basis of vaginal sampling (50%, but not significantly higher than for rectal sampling (82%. Direct plating of the rectovaginal swab on CNA, GBSDA and CA resulted in detection of 59, 91 and 95% of the carriers, respectively, whereas subculturing of Lim broth yielded 77, 95 and 100% positivity, respectively. Lim broth enrichment enabled the detection of only one additional GBS positive subject. There was no significant difference between GBSDA and CA, whereas both were more sensitive than CNA. Direct culture onto GBSDA or CA (91 and 95% detected more carriers than Lim broth enrichment and subculture onto CNA (77%. One false negative isolate was observed on GBSDA, and three false positives on CA. Conclusions In

  1. [Prevention of perinatal infection caused by group B beta-hemolytic streptococcus].

    Science.gov (United States)

    Bevilacqua, G

    1999-01-01

    Streptococcus agalactiae strains or group B streptococci (GBS) are the leading cause of bacterial pneumoniae, sepsis and meningitis in neonates. GBS is also a major cause of bacteriemia in pregnant women. Colonization of the human rectovaginal tract with GBS is a risk factor associated with chorioamnionitis and transmission of the infection to the infant. Neonatal exposure to high concentrations of GBS, mainly during vaginal delivery, leads to colonisation of the lung airways and subsequent onset of severe diseases like pneumonia, sepsis and menigitis. GBS is present in the genitourinary tract of 10% to 40% of pregnant women, about 50% of the newborns of these mothers will be colonised during delivery and of these neonates, 1% to 2% present a severe invasive disease. The early-onset disease, appear in the neonates within 7 days of life and more than 90% occur within the first day of life. Fatal infection is associated commonly with fulminat and overwhelming early-onset disease. Maternal-intrapartum chemoprophylaxis is able to prevent the transmission of GBS to the newborn and to reduce the frequency and the severity of early onset disease. In many countries, in particular in US, several recommendations have been proposed to prevent the perinatal GBS infection. In this paper some recommendations to prevent GBS disease of the newborn, performed in collaboration with Italian Society of Perinatal Medicine, are presented. The most important problem in the prevention programme is the identification of the cases to treat, since it is not possible to give antibiotics to all the women. We combine two strategies for the identification of the women to be treated, one risk based and the other screening based. Intra-partum administration of ampicillin or penicillin is recommended for the women with one or more risk-factors (labour = 18 hours, intrapartum temperature > = 38 degrees C, previous infant with invasive GBS disease, diabetes) and for women with collect vaginal and

  2. Multiple-locus variant-repeat assay (MLVA) is a useful tool for molecular epidemiologic analysis of Streptococcus agalactiae strains causing bovine mastitis.

    Science.gov (United States)

    Radtke, Andreas; Bruheim, Torkjel; Afset, Jan Egil; Bergh, Kåre

    2012-06-15

    Group B streptococci (GBS) were considered a major cause of mastitis in cattle until preventive measures succeeded in controlling the disease in the 1970s and 1980s. During the last 5-6 years an increasing number of cases have been observed in some Scandinavian countries. A total of 187 GBS isolates from mastitis cases were collected from 119 animals in 34 Norwegian farms in the period from April 2007 to November 2010. 133 (71%) of the isolates were from farms with automated milking systems. The strains underwent typing of capsular polysaccharides (CPS) and surface proteins, and were analyzed by multi-locus variable repeat assay (MLVA) to investigate the epidemiological relationship of strains within and between farms. The GBS strains were differentiated into 12 types by CPS and surface protein analysis, with CPS types V (54%) and IV (34%) predominating. MLVA was superior to CPS and protein typing for strain differentiation, resolving the 187 strains into 37 types. In 29 of 34 farms all GBS strains had identical MLVA profiles specific for each farm. However, in one farm represented with 48 isolates, four MLVA variants with differences in one repeat locus were observed during the almost 3-year long collection period. Similar variations were observed at four other farms. This might reflect the stability of repeat loci under in vivo conditions. Farms with automated milking systems were overrepresented in this material. In conclusion, the five-loci MLVA allowed rapid high-resolution genotyping of the bovine GBS strains within and between farms. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Hibridación in situ para la detección de streptococcus agalactiae en tejidos de tilapia (oreochromis sp.)

    OpenAIRE

    Pulido, E. A.; Iregui, C. A.

    2010-01-01

    La estreptococosis es uno de los problemas sanitarios más serios en la acuicultura mundial. En Colombia la enfermedad afecta de manera importante las explotaciones de tilapia. se estandarizó la técnica de hibridación in situ (HIS ) en tejidos de tilapia previamente identificados como positivos a la presencia de S. agalactiae por la técnica de inmunoperoxidasa indirecta (IPI) y microbiología. Se obtuvo señal positiva en el interior de los granulomas con u...

  4. Influencia de la composición del medio de cultivo sobre la producción de pigmento por Streptococcus agalactiae

    OpenAIRE

    Carazo Carazo, Concepción

    2011-01-01

    Se ha estudiado la influencia de la composición del medio de cultivo sobre la producción de pigmento por s. agalactiae partiendo de un medio de cultivo diseñado para tal finalidad (new granada medium), eliminando uno a uno los componentes incluidos en su formulación original. Almidón, proteosa peptona (difco), suero, fosfatos y metrotexato influyen de forma importante en la formación y/o visualización del pigmento producido por este microorganismo. Se ha determinado que la fracción de proteos...

  5. Reduction of the use of antimicrobial drugs following the rapid detection of Streptococcus agalactiae in the vagina at delivery by real-time PCR assay.

    Science.gov (United States)

    Poncelet-Jasserand, E; Forges, F; Varlet, M-N; Chauleur, C; Seffert, P; Siani, C; Pozzetto, B; Ros, A

    2013-08-01

    To assess whether the determination of the presence of group B streptococci (GBS) in the vagina using a rapid polymerase chain reaction (PCR) assay at delivery was able to spare useless antimicrobial treatments, as compared with conventional culture at 34-38 weeks of gestation. Practical evaluation and prospective cost-effectiveness analysis. A university hospital in France. A cohort of 225 women in labour at the University-Hospital of Saint-Etienne. Each woman had a conventional culture performed at 34-38 weeks of gestation. At the beginning of labour, two vaginal swabs were sampled for rapid PCR testing and culture. The decision to prescribe a prophylactic antimicrobial treatment or not was taken according to the result of the PCR test. A comparative cost-effectiveness analysis of the two diagnostic strategies was carried out. Number of women receiving inadequate prophylactic antimicrobial drugs following each testing strategy, costs of PCR testing and culture, frequency of vaginal GBS, and diagnostic performance of the PCR test at delivery. The percentage of unnecessarily treated women was significantly reduced using the rapid test versus conventional culture (4.5 and 13.6%, respectively; P < 0.001). The rate of vaginal GBS at delivery was 12.5%. The incremental cost-effectiveness ratio (ICER) for each inadequate management avoided was €36 and €173 from the point of view of the healthcare system and hospital, respectively. The PCR assay reduced the number of inadequate antimicrobial treatments aimed to prevent the early onset of GBS disease. However, this strategy generates extra costs that must be put into balance with its clinical benefits. © 2013 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2013 RCOG.

  6. The GBS PI-2a pilus is required for virulence in mice neonates.

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    Salvatore Papasergi

    2011-04-01

    Full Text Available Streptococcus agalactiae (Group B Streptococcus is a leading cause of sepsis and meningitis in newborns. Most bacterial pathogens, including gram-positive bacteria, have long filamentous structures known as pili extending from their surface. Although pili are described as adhesive organelles, they have been also implicated in many other functions including thwarting the host immune responses. We previously characterized the pilus-encoding operon PI-2a (gbs1479-1474 in strain NEM316. This pilus is composed of three structural subunit proteins: PilA (Gbs1478, PilB (Gbs1477, and PilC (Gbs1474, and its assembly involves two class C sortases (SrtC3 and SrtC4. PilB, the bona fide pilin, is the major component whereas PilA, the pilus associated adhesin, and PilC the pilus anchor are both accessory proteins incorporated into the pilus backbone.In this study, the role of the major pilin subunit PilB was tested in systemic virulence using 6-weeks old and newborn mice. Notably, the non-piliated ΔpilB mutant was less virulent than its wild-type counterpart in the newborn mice model. Next, we investigated the possible role(s of PilB in resistance to innate immune host defenses, i.e. resistance to macrophage killing and to antimicrobial peptides. Phagocytosis and survival of wild-type NEM316 and its isogenic ΔpilB mutant in immortalized RAW 264.7 murine macrophages were not significantly different whereas the isogenic ΔsodA mutant was more susceptible to killing. These results were confirmed using primary peritoneal macrophages. We also tested the activities of five cationic antimicrobial peptides (AMP-1D, LL-37, colistin, polymyxin B, and mCRAMP and found no significant difference between WT and ΔpilB strains whereas the isogenic dltA mutant showed increased sensitivity.These results question the previously described role of PilB pilus in resistance to the host immune defenses. Interestingly, PilB was found to be important for virulence in the neonatal

  7. Hibridación in situ para la detección de Streptococcus agalactiae en tejidos de tilapia (Oreochromis sp.

    Directory of Open Access Journals (Sweden)

    E. A. Pulido

    2010-04-01

    Full Text Available La estreptococosis es uno de los problemas sanitarios más serios en la acuicultura mundial.En Colombia la enfermedad afecta de manera importante las explotaciones detilapia. Se estandarizó la técnica de hibridación in situ (HIS en tejidos de tilapia previamenteidentificados como positivos a la presencia de S. agalactiae por la técnicade inmunoperoxidasa indirecta (IPI y microbiología. Se obtuvo señal positiva en elinterior de los granulomas con una especificidad del 100%. Se logró amplificar significativamentela señal mediante el uso de la tiramida. La HIS en tejidos de tilapia puedeser usada para el diagnóstico y estudios de patogenésis y epidemiológicos con este microorganismo.Se requieren futuras investigaciones para optimizar la marcación de lasbacterias libres en los tejidos y evaluar la sensibilidad de la técnica.

  8. Hibridación in situ para la detección de streptococcus agalactiae en tejidos de tilapia (oreochromis sp.

    Directory of Open Access Journals (Sweden)

    E. A. Pulido

    2010-01-01

    Full Text Available La estreptococosis es uno de los problemas sanitarios más serios en la acuicultura mundial. En Colombia la enfermedad afecta de manera importante las explotaciones de tilapia. se estandarizó la técnica de hibridación in situ (HIS en tejidos de tilapia previamente identificados como positivos a la presencia de S. agalactiae por la técnica de inmunoperoxidasa indirecta (IPI y microbiología. Se obtuvo señal positiva en el interior de los granulomas con una especificidad del 100%. Se logró amplificar significativamente la señal mediante el uso de la tiramida. La HIS en tejidos de tilapia puede ser usada para el diagnóstico y estudios de patogenésis y epidemiológicos con este microorganismo. Se requieren futuras investigaciones para optimizar la marcación de las bacterias libres en los tejidos y evaluar la sensibilidad de la técnica.

  9. GBS public awareness, advocacy, and prevention--what's working, what's not and why we need a maternal GBS vaccine.

    Science.gov (United States)

    Burns, Gina; Plumb, Jane

    2013-08-28

    Group B Streptococcus (GBS) is the most common cause of severe early-onset (0-6 days) infection and a significant cause of serious late-onset (7-90 days) infection in infants. While most babies recover from their GBS infection, some are stillborn, more die in the first weeks of life and others suffer lifelong disability. Despite efforts in many developed countries to prevent these infections, the burden of GBS disease remains significant, particularly among the late onset infections, which are not preventable using current risk-based or screening strategies. Vaccination, once available, could prevent more cases of GBS infection than any other strategy, including preventing preterm labor and stillbirths caused by GBS infection, post-delivery GBS infection in the mother and late-onset GBS infection in the baby. Vaccination would also avoid allergic reactions to antibiotics and concern about the emergence of antibiotic resistant bacteria. We consider the history of the two largest group B Strep parent organizations (Group B Strep Association USA and Group B Strep Support UK) and the history of GBS prevention in their respective countries. We look at what is needed before a vaccine can be introduced and consider how acceptable a GBS vaccine would be from families' perspective. We also summarize what a perfect GBS vaccine would look like and what we should all strive to achieve. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Evaluation of procedures for typing of group B Streptococcus: a retrospective study

    Directory of Open Access Journals (Sweden)

    Hans-Christian Slotved

    2017-03-01

    Full Text Available Background This study evaluates two procedures for typing of Streptococcus agalactiae (group B streptococci; GBS isolates, using retrospective typing data from the period 2010 to 2014 with a commercial latex agglutination test (latex test and the Lancefield precipitation test (LP test. Furthermore, the genotype distribution of phenotypically non-typable (NT GBS isolates is presented. We also raise the awareness, that the difference in typing results obtained by phenotypical methods and genotype based methods may have implications on vaccine surveillance in case a GBS vaccine is introduced. Methods A total of 616 clinical GBS isolates from 2010 to 2014 were tested with both a latex test and the LP test. Among these, 66 isolates were genotyped by PCR, including 41 isolates that were phenotypically NT. Results The latex test provided a serotype for 83.8% of the isolates (95% CI [80.7–86.6] compared to 87.5% (95% CI [84.6–90.0] obtained by the LP method. The two assays provided identical capsular identification for all sero-typeable isolates (excluding NT isolates. The PCR assay provided a genotype designation to the 41 isolates defined as phenotypically NT isolates. Discussion We found that the latex test showed a slightly lower identification percentage than the LP test. Our recommendation is to use the latex agglutination as the routine primary assay for GBS surveillance, and then use the more labour intensive precipitation test on the NT isolates to increase the serotyping rate. A genotype could be assigned to all the phenotypically NT isolates, however, as a consequence genotyping will overestimate the coverage from possible future capsular polysaccharide based GBS vaccines.

  11. The changing epidemiology of group B streptococcus bloodstream infection

    DEFF Research Database (Denmark)

    Ballard, Mark S; Schønheyder, Henrik C; Knudsen, Jenny Dahl

    2016-01-01

    Background Population-based studies conducted in single regions or countries have identified significant changes in the epidemiology of invasive group B streptococcus (GBS) infection. However, no studies have concurrently compared the epidemiology of GBS infections among multiple different region...

  12. Antimicrobial resistance and molecular epidemiology of streptococci from bovine mastitis

    DEFF Research Database (Denmark)

    Rato, Márcia G.; Bexiga, Ricardo; Florindo, Carlos

    2013-01-01

    Streptococcus agalactiae (Group B Streptococcus, GBS), Streptococcus dysgalactiae subsp. dysgalactiae (Group C Streptococcus, GCS) and Streptococcus uberis are relevant mastitis pathogens, a highly prevalent and costly disease in dairy industry due to antibiotherapy and loss in milk production. T...

  13. Estimation of test characteristics of real-time PCR and bacterial culture for diagnosis of subclinical intramammary infections with Streptococcus agalactiae in Danish dairy cattle in 2012 using latent class analysis

    DEFF Research Database (Denmark)

    Mahmmod, Yasser; Toft, Nils; Katholm, Jørgen

    2013-01-01

    threshold (Ct) values against bacterial culture (BC) for diagnosis of S. agalactiae IMI using latent class analysis to avoid the assumption of a perfect reference test. A total of 614 dairy cows were randomly selected from 6 herds with bulk tank PCR Ct value ≤ 39 for S. agalactiae and S. aureus. At milk...... cut-offs, indicating under estimation of S. agalactiae IMI in the examined dairy cows. In conclusion, Se of PCR is always higher than Se of BC at all tested cut-offs. The lower cut-off, the more comparable becomes Se of PCR and Se of BC. The changes in Se in both PCR and BC at different Ct-value cut...... definition of infection may reflect a more general condition of cows being positive for S. agalactiae. Our findings indicate that PCR Ct-value cut-offs should be chosen according to the underlying latent infection definition of interest. Latent class analysis proposes a useful alternative to classic test...

  14. Comprehensive evaluation of immunomodulation by moderate hypoxia in S. agalactiae vaccinated Nile tilapia.

    Science.gov (United States)

    Gallage, Sanchala; Katagiri, Takayuki; Endo, Masato; Maita, Masashi

    2017-07-01

    Streptococcus agalactiae is a major bacterial pathogen in tilapia aquaculture. Vaccines are known to provide protection but S. agalactiae clearance in tilapia can be reduced by marginal environmental conditions. Therefore, the purpose of this study is to examine S. agalactiae clearance in vaccinated Nile tilapia under moderate hypoxic (55± 5% DO) and normoxic (85 ± 5%DO) conditions. Fish were acclimatized to either moderate hypoxia or normoxia and immunized with formalin-inactivated S. agalactiae. Fish were experimentally challenged with S. agalactiae at 30 days post-vaccination. Serum antibody titer was significantly higher in vaccinated fish kept under normoxic condition compared to the moderate hypoxic condition at fifteen and thirty days post-vaccination. The cumulative mortality following challenge was significantly reduced in vaccinated fish kept under normoxic condition compared to those in moderate hypoxic condition reflecting that pre-challenge antibody titer may correlate with survival of fish. Blood and tissue pathogen burden detection of S. agalactiae studies revealed that culturable S. agalactiae cells could not be detected in the blood of normoxic vaccinated fish at all the sampling points. In contrast, fish vaccinated in moderate hypoxic condition had considerable number of culturable S. agalactiae cells in their blood up to 5 days following challenge. Phagocytosis and intracellular reactive oxygen species (ROS) production were lowered by moderate hypoxia in vitro. Furthermore, presence of specific antibodies and higher specific antibody level in the serum increased phagocytosis, ROS production and lowered intracellular survival of S. agalactiae in head kidney leukocytes. Overall this study has highlighted that S. agalactiae clearance in vaccinated Nile tilapia is modulated by moderate hypoxia. One of the possible explanations for this might be less efficient phagocytic activities due to low oxygen availability and lower specific

  15. Quimioprofilaxis para evitar la colonización materna por estreptococo grupo B: consecuencias de no adoptar la recomendación internacional Maternal chemoprophylaxis against group B Streptococcus colonization: the consequences of not adopting the international recommendation

    Directory of Open Access Journals (Sweden)

    Jesús Reyna-Figueroa

    2008-04-01

    Full Text Available OBJETIVO: Conocer el criterio para la quimioprofilaxis en mujeres embarazadas colonizadas con Streptococcus agalactiae (SGB y las repercusiones de la infección en México. MATERIAL Y MÉTODOS: Se identificó a mujeres embarazadas con SGB mediante el cultivo cervicovaginal y/o urinario en una revisión de cinco años. Se formaron dos grupos: con uso de quimioprofilaxis, el primero, y sin uso de la misma, el segundo. Con base en la utilización de la prueba de ji cuadrada se determinó la diferencia de proporciones. La aproximación de ji cuadrada para la distribución de Poisson comparó los promedios de la infección neonatal. RESULTADOS: Se notificaron 274 cultivos positivos para SGB en 261 pacientes; 165 (60.2% cervicovaginales, 109 (39.7% urinarios, y en 13 pacientes (4.7% se obtuvo resultado positivo en ambos. De las 261 pacientes, 53 (5.6% recibieron profilaxis intraparto (pOBJECTIVE: To know the criteria which determine the chemoprophylaxis on pregnant women colonized by Streptococcus agalactiae (GBS and the impact in our environment. MATERIAL AND METHODS: A retrospective analysis, identifying pregnant women with isolation of Streptococcus agalactiae on screening cultures, cervical swabs and urine culture. Two groups were analyzed, group 1 received chemoprophylaxis, and group 2 without chemoprophylaxis. Chi square was used to asses the difference between proportions. Chi square approximation to Poisson distribution was used to compare the means of neonatal infection. RESULTS: A total of 274 cultures were reported with GBS isolation, on 261 patients; 165 (60.2% cervical swabs, 109 (39.7% urine culture and 13 patients from 274 (4.7% had positive culture on both specimens. Of this 261 patients, 53 (5.6% received chemoprophylaxis during labor (p<0.05. The CDC criteria were followed accuracy on 29.2%. CONCLUSIONS: There have not been established criteria for screening colonization by GBS in Mexican pregnant women.

  16. Contribution of the RgfD Quorum Sensing Peptide to rgf Regulation and Host Cell Association in Group B Streptococcus

    Directory of Open Access Journals (Sweden)

    Robert E. Parker

    2017-01-01

    Full Text Available Streptococcus agalactiae (group B Streptococcus; GBS is a common inhabitant of the genitourinary and/or gastrointestinal tract in up to 40% of healthy adults; however, this opportunistic pathogen is able to breach restrictive host barriers to cause disease and persist in harsh and changing conditions. This study sought to identify a role for quorum sensing, a form of cell to cell communication, in the regulation of the fibrinogen-binding (rgfBDAC two-component system and the ability to associate with decidualized endometrial cells in vitro. To do this, we created a deletion in rgfD, which encodes the putative autoinducing peptide, in a GBS strain belonging to multilocus sequence type (ST-17 and made comparisons to the wild type. Sequence variation in the rgf operon was detected in 40 clinical strains and a non-synonymous single nucleotide polymorphism was detected in rgfD in all of the ST-17 genomes that resulted in a truncation. Using qPCR, expression of rgf operon genes was significantly decreased in the ST-17 ΔrgfD mutant during exponential growth with the biggest difference (3.3-fold occurring at higher cell densities. Association with decidualized endometrial cells was decreased 1.3-fold in the mutant relative to the wild type and rgfC expression was reduced 22-fold in ΔrgfD following exposure to the endometrial cells. Collectively, these data suggest that this putative quorum sensing molecule is important for attachment to human tissues and demonstrate a role for RgfD in GBS pathogenesis through regulation of rgfC.

  17. Benih Keturunan Induk Ikan Nila yang Divaksinasi pada Tingkat Kematangan Gonad-2 Lebih Tahan Terhadap Infeksi Streptococcus agalactiae (RESISTANCE OF TILAPIA (OREOCHRIMIS NILOTICUS FRY VACCINATED AT DIFFERENT GONADAL DEVELOPMENTAL STAGES TOWARD STREPTOCO

    Directory of Open Access Journals (Sweden)

    Khairun Nissa

    2016-11-01

    Full Text Available The aim of this study was to evaluate the effectiveness of vaccination based on gonad maturationstages on tilapia brood stocks in which the released antibodies was able to be transferred to the seed.Vaccine composed with whole cells and extracellular product (ECP was injected at stage 2 and stage 3 ofthe gonad development stages at concentration of 109 CFU mL1 as much as 4 mL to 1 kg of brood fish.Control fish was unvaccinated treatment. Challenge study at seed was conducted by immersing S. agalactiaefor 30 minutes at 7, 14, 21, and 28 days post hatching (DPH in 107 CFU/mL. Antibody levels on broodstocks, eggs, and body fluids of seed, and relative percentage survival (RPS of seed post challenge studywere evaluated. The results showed that stage 2 of gonad developmental stages was found on 7 days postinitial spawning and stage 3 found on 14 days post initial spawning of brood fish. Vaccinated done in stage 2 of gonad developmental stages gave immunoglobulin serum in brood (0,166±0,001, egg (0,165±0,002,and seed aged 7, 14, 21, and 28 days post hatching (0,164±0,002, 0,162±0,005, 0,155±0,006, and 0,14±0,008respectively were significantly higher (P<0,05 compared to other treatment. Challenged test that doneby immersing with S. agalactiae suspension on larval aged 7, 14, 21, and 28 days had highest RPS(95,24%, 83,33%, 72,22%, and 56,02% respectively formed on seed from brood stock vaccination in gonaddevelopment stage 2. Vaccination in tilapia brood stocks at stage 2 of gonad developmental stages gavehighest protection by maternal immunity to the seed against S. agalactiae.

  18. STREPTOCOCCUS: A WORLDWIDE FISH HEALTH PROBLEM

    Science.gov (United States)

    Streptococcus iniae and S. agalactiae are important emergent pathogens that affect many fish species worldwide, especially in warm-water regions. In marine and freshwater systems, these Gram-positive bacteria cause significant economic losses, estimated at hundreds of millions of dollars annually. ...

  19. Exposición a Estreptococo del grupo B en mujeres mexicanas en edad reproductiva Serologic evidence of high exposure to Group B streptococci (Streptococcus agalactiae in Mexican women of reproductive age

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    Gerardo Palacios-Saucedo

    2002-01-01

    Full Text Available Objetivo. Evaluar la seroprevalencia de la infección por Estreptococo del grupo B (EGB en una muestra representativa de mujeres en edad reproductiva de la República Mexicana. Material y métodos. Se estudió una muestra representativa de sueros de la población femenina mexicana de 15 a 40 años de edad, de todos los niveles socioeconómicos. La muestra fue seleccionada del Banco Nacional de Sueros por muestreo aleatorio simple por computadora. Los sueros se obtuvieron durante la última encuesta seroepidemiológica nacional realizada en 1987 y 1988. Los ensayos para la estandarización y la evaluación de la seroprevalencia se llevaron a cabo en el Hospital de Pediatría del Centro Médico Nacional Siglo XXI, del Instituto Mexicano del Seguro Social (IMSS entre enero y noviembre de 1995. Se midieron anticuerpos IgG antipolisacárido de grupo de EGB usando un ensayo inmunoenzimático (ELISA estandarizado y validado en el laboratorio, utilizando un antígeno específico de grupo, producido y purificado a partir de la cepa de referencia de EGB 110. Resultados. Se estudió un total de 2 669 muestras de suero, de las cuales 2 405 fueron positivas para la presencia de anticuerpos IgG contra el antígeno de grupo de EGB. Esto corresponde a una seroprevalencia de 90.2 %. No hubo diferencia en los porcentajes de seropositividad por grupos de edad ni por entidades federativas. Conclusiones. Se detectó una elevada prevalencia de anticuerpos contra el antígeno de grupo del EGB. Los resultados de este estudio sugieren que existe una elevada exposición de las mujeres mexicanas jóvenes a este microrganismo.Objective. To assess the prevalence of IgG antibodies against Group B streptococci (GBS among women of reproductive age in Mexico. Material and Methods. Serum specimens were drawn from 15 to 40 year-old women, representative of all regions and socioeconomic levels of the country. The sample was randomly selected from Banco Nacional de Sueros (National

  20. Maternal vaginorectal colonization by Group B Streptococcus and ...

    African Journals Online (AJOL)

    During labour GBS and Listeria monocytogenes may infect the new-borns, leading to neonatal sepsis and meningitis. So far, there is no report on prevalence of GBS and Listeria monocytogenes among pregnant women in Mwanza. The objective of the study was to determine the magnitude of Group B Streptococcus and ...

  1. Evolution and Diversity of the Antimicrobial Resistance Associated Mobilome in Streptococcus suis: A Probable Mobile Genetic Elements Reservoir for Other Streptococci.

    Science.gov (United States)

    Huang, Jinhu; Ma, Jiale; Shang, Kexin; Hu, Xiao; Liang, Yuan; Li, Daiwei; Wu, Zuowei; Dai, Lei; Chen, Li; Wang, Liping

    2016-01-01

    Streptococcus suis is a previously neglected, newly emerging multidrug-resistant zoonotic pathogen. Mobile genetic elements (MGEs) play a key role in intra- and interspecies horizontal transfer of antimicrobial resistance (AMR) determinants. Although, previous studies showed the presence of several MGEs, a comprehensive analysis of AMR-associated mobilome as well as their interaction and evolution has not been performed. In this study, we presented the AMR-associated mobilome and their insertion hotspots in S. suis . Integrative conjugative elements (ICEs), prophages and tandem MGEs were located at different insertion sites, while 86% of the AMR-associated MGEs were inserted at rplL and rum loci. Comprehensive analysis of insertions at rplL and rum loci among four pathogenic Streptococcus species ( Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes , and S. suis ) revealed the existence of different groups of MGEs, including Tn5252, ICE Sp 1108, and TnGBS2 groups ICEs, Φm46.1 group prophage, ICE_ICE and ICE_prophage tandem MGEs. Comparative ICE genomics of ICE Sa 2603 family revealed that module exchange and acquisition/deletion were the main mechanisms in MGEs' expansion and evolution. Furthermore, the observation of tandem MGEs reflected a novel mechanism for MGE diversity. Moreover, an in vitro competition assay showed no visible fitness cost was observed between different MGE-carrying isolates and a conjugation assay revealed the transferability of ICE Sa 2603 family of ICEs. Our statistics further indicated that the prevalence and diversity of MGEs in S. suis is much greater than in other three species which prompted our hypothesis that S. suis is probably a MGEs reservoir for other streptococci. In conclusion, our results showed that acquisition of MGEs confers S. suis not only its capability as a multidrug resistance pathogen, but also represents a paradigm to study the modular evolution and matryoshkas of MGEs.

  2. Evolution and diversity of the antimicrobial resistance associated mobilome in Streptococcus suis: a probable mobile genetic elements reservoir for other streptococci

    Directory of Open Access Journals (Sweden)

    Jinhu Huang

    2016-10-01

    Full Text Available Streptococcus suis is a previously neglected, newly emerging multidrug-resistant zoonotic pathogen. Mobile genetic elements (MGEs play a key role in intra- and interspecies horizontal transfer of antimicrobial resistance (AMR determinants. Although previous studies showed the presence of several MGEs, a comprehensive analysis of AMR-associated mobilome as well as their interaction and evolution has not been performed. In this study, we presented the AMR-associated mobilome and their insertion hotspots in S. suis. Integrative conjugative elements (ICEs, prophages and tandem MGEs were located at different insertion sites, while 86% of the AMR-associated MGEs were inserted at rplL and rum loci. Comprehensive analysis of insertions at rplL and rum loci among four pathogenic Streptococcus species (Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes, and S. suis revealed the existence of different groups of MGEs, including Tn5252, ICESp1108, and TnGBS2 groups ICEs, Φm46.1 group prophage, ICE_ICE and ICE_prophage tandem MGEs. Comparative ICE genomics of ICESa2603 family revealed that module exchange and acquisition/deletion were the main mechanisms in MGEs’ expansion and evolution. Furthermore, the observation of tandem MGEs reflected a novel mechanism for MGE diversity. Moreover, an in vitro competition assay showed no visible fitness cost was observed between different MGE-carrying isolates and a conjugation assay revealed the transferability of ICESa2603 family of ICEs. Our statistics further indicated that the prevalence and diversity of MGEs in S. suis is much greater than in other three species which prompted our hypothesis that S. suis is probably a MGEs reservoir for other streptococci. In conclusion, our results showed that acquisition of MGEs confers S. suis not only its capability as a multidrug resistance pathogen, but also represents a paradigm to study the modular evolution and matryoshkas of MGEs.

  3. Vaccination against group B streptococcus.

    Science.gov (United States)

    Heath, Paul T; Feldman, Robert G

    2005-04-01

    Streptococcus agalactiae (Group B streptococcus) is an important cause of disease in infants, pregnant women, the elderly and in immunosuppressed adults. An effective vaccine is likely to prevent the majority of infant disease (both early and late onset), as well as Group B streptococcus-related stillbirths and prematurity, to avoid the current real and theoretical limitations of intrapartum antibiotic prophylaxis, and to be cost effective. The optimal time to administer such a vaccine would be in the third trimester of pregnancy. The main limitations on the production of a Group B streptococcus vaccine are not technical or scientific, but regulatory and legal. A number of candidates including capsular conjugate vaccines using traditional carrier proteins such as tetanus toxoid and mutant diphtheria toxin CRM197, as well as Group B streptococcus-specific proteins such as C5a peptidase, protein vaccines using one or more Group B streptococcus surface proteins and mucosal vaccines, have the potential to be successful vaccines. The capsular conjugate vaccines using tetanus and CRM197 carrier proteins are the most advanced candidates, having already completed Phase II human studies including use in the target population of pregnant women (tetanus toxoid conjugate), however, no definitive protein conjugates have yet been trialed. However, unless the regulatory environment is changed specifically to allow the development of a Group B streptococcus vaccine, it is unlikely that one will ever reach the market.

  4. Consideraciones sobre elaislamiento en exudados vaginales de Streptococcus morbillorum

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    J.M. F. Egido

    1995-06-01

    Full Text Available De el estúdio de 195 exudados vaginales enviados por el Servicio de Ginecologia de este hospital, durante el período 1988-1990, hemos seleccionado aquellos en los que el cultivo fue positivo para estreptococos, 58 (30% de los cuales 26 (44.8% correspondia a Streptococcus morbillorum, 9 (15.5% a Gardnerella vaginalis, 5 (8.6% a Enterococcus faecalis-durans, y a Streptococcus agalactiae, 3 (5.1% a Streptococcus mitis y Streptococcus mitis, 2 (3-4% a Streptococcus bovis y Streptococcus cremoris y 1 (1.7% a Streptococcus salivarius, Streptococcus equinus y Strptococcus sanguis II respectivamente. En todos los casos se observo antecedentes de actuacción medico- quirurjica en el tracto genital, y en el 52.8% de los casos fuô concomitante con el diagnostico clinico-micologico de candidiasis vaginal. La ideittificaccion bacteriologica se realizo mediante el sistema API 20 STREP (sistema api bioMêríeux GmbH, Nütingen, Alemania dando un patron tipico ("excelente identificacción" para el Streptococcus morbillorum.We have tested 195 vaginal secretions sent by Gynecology Service of this hospital between the years 1988 - 1990. We achieved positive culture for streptococci in 58 (30% of these cultures, 26 (44.8% corresponding to Streptococcus morbillorum 9 (15.5%, to Gardnerella vaginalis 5 (8.6%, to Enterococcus faecalis-durans and to Streptococcus agalactiae, 3 (5.1 % to Streptococcus mitis and milleri 2 (3-4%, to Streptococcus bovis and cremoris, and 1 (1.7% to Streptococcus salivarius, equinus and sanguis II respectively. We previously found that 52.8% of these patients were positive for vaginal candidiasis. The bacteriological identification done by the API 20 STREP System (bioMerieux GmbH, Nútingen, Germanyprovides a typical pattern ("good identification" for the Streptococcus morbillorum.

  5. Disparities in universal prenatal screening for group B streptococcus--North Carolina, 2002-2003.

    Science.gov (United States)

    2005-07-22

    Group B streptococcus (GBS) is a leading cause of neonatal morbidity and mortality in the United States. Intrapartum antibiotics administered to women at risk for transmitting GBS to their newborns are effective in preventing perinatal GBS infection. In 2002, CDC, the American Academy of Pediatrics, and the American College of Obstetricians and Gynecologists recommended universal prenatal screening for vaginal and rectal GBS colonization at 35-37 weeks' gestation. To examine prenatal GBS screening among pregnant women in North Carolina, CDC analyzed 2002 and 2003 data from the North Carolina Pregnancy Risk Assessment Monitoring System (PRAMS). The proportions of women reporting prenatal screening for GBS were similar in 2002 and 2003 (70% and 74%, respectively); however, for both years, women of Hispanic ethnicity and women who received prenatal care at a hospital or health department clinic were less likely to report prenatal screening for GBS. These findings underscore the need to increase GBS-related education and prevention activities targeted to these populations.

  6. Comparative evaluation of 5 different selective media for Group B Streptococcus screening in pregnant women.

    Science.gov (United States)

    Joubrel, Caroline; Gendron, Nicolas; Dmytruk, Nicolas; Touak, Gérald; Verlaguet, Martine; Poyart, Claire; Réglier-Poupet, Hélène

    2014-12-01

    We compared the performances and the cost-effectiveness of 5 selective media for Group B Streptococcus (GBS) screening in vaginal samples from pregnant women. The usefulness of these media is unquestionable for GBS screening; the choice will depend largely on the laboratory organization. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Mast cell degranulation by a hemolytic lipid toxin decreases GBS colonization and infection

    OpenAIRE

    Gendrin, Claire; Vornhagen, Jay; Ngo, Lisa; Whidbey, Christopher; Boldenow, Erica; Santana-Ufret, Veronica; Clauson, Morgan; Burnside, Kellie; Galloway, Dionne P.; Waldorf, Kristina Adams; Piliponsky, Adrian M.; Rajagopal, Lakshmi

    2015-01-01

    Ascending infection of microbes from the lower genital tract into the amniotic cavity increases the risk of preterm birth, stillbirth, and newborn infections. Host defenses that are critical for preventing ascending microbial infection are not completely understood. Group B Streptococcus (GBS) are Gram-positive bacteria that frequently colonize the lower genital tract of healthy women but cause severe infections during pregnancy, leading to preterm birth, stillbirth, or early-onset newborn in...

  8. Streptococcus agalactiae Serotype IV in Humans and Cattle, Northern Europe

    DEFF Research Database (Denmark)

    Lyhs, Ulrike; Kulkas, Laura; Katholm, Jorgen

    2016-01-01

    not differentiate between populations isolated from different host species. Isolates from humans and cattle differed in lactose fermentation, which is encoded on the accessory genome and represents an adaptation to the bovine mammary gland. Serotype IV-ST196 isolates were obtained from multiple dairy herds in both...

  9. Capsular Sialyltransferase Specificity Mediates Different Phenotypes in Streptococcus suis and Group B Streptococcus

    Directory of Open Access Journals (Sweden)

    David Roy

    2018-04-01

    Full Text Available The capsular polysaccharide (CPS represents a key virulence factor for most encapsulated streptococci. Streptococcus suis and Group B Streptococcus (GBS are both well-encapsulated pathogens of clinical importance in veterinary and/or human medicine and responsible for invasive systemic diseases. S. suis and GBS are the only Gram-positive bacteria which express a sialylated CPS at their surface. An important difference between these two sialylated CPSs is the linkage between the side-chain terminal galactose and sialic acid, being α-2,6 for S. suis but α-2,3 for GBS. It is still unclear how sialic acid may affect CPS production and, consequently, the pathogenesis of the disease caused by these two bacterial pathogens. Here, we investigated the role of sialic acid and the putative effect of sialic acid linkage modification in CPS synthesis using inter-species allelic exchange mutagenesis. To this aim, a new molecular biogenetic approach to express CPS with modified sialic acid linkage was developed. We showed that sialic acid (and its α-2,6 linkage is crucial for S. suis CPS synthesis, whereas for GBS, CPS synthesis may occur in presence of an α-2,6 sialyltransferase or in absence of sialic acid moiety. To evaluate the effect of the CPS composition/structure on sialyltransferase activity, two distinct capsular serotypes within each bacterial species were compared (S. suis serotypes 2 and 14 and GBS serotypes III and V. It was demonstrated that the observed differences in sialyltransferase activity and specificity between S. suis and GBS were serotype unrestricted. This is the first time that a study investigates the interspecies exchange of capsular sialyltransferase genes in Gram-positive bacteria. The obtained mutants represent novel tools that could be used to further investigate the immunomodulatory properties of sialylated CPSs. Finally, in spite of common CPS structural characteristics and similarities in the cps loci, sialic acid exerts

  10. Liamocin oil from Aureobasidium pullulans has antibacterial activity with specificity for species of Streptococcus

    Science.gov (United States)

    Liamocin oil from Aureobasidium pullulans NRRL 50380 was tested for antibacterial activity. Liamocins inhibited growth of Streptococcus agalactiae, S. uberis, S. mitis, S. infantarius, and S. mutans, with minimum inhibitory concentrations from 20 'g/ml to 78 'g/ml. Enterococcus faecalis was less sus...

  11. Consideraciones sobre elaislamiento en exudados vaginales de Streptococcus morbillorum

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    J.M. F. Egido

    1995-06-01

    Full Text Available De el estúdio de 195 exudados vaginales enviados por el Servicio de Ginecologia de este hospital, durante el período 1988-1990, hemos seleccionado aquellos en los que el cultivo fue positivo para estreptococos, 58 (30% de los cuales 26 (44.8% correspondia a Streptococcus morbillorum, 9 (15.5% a Gardnerella vaginalis, 5 (8.6% a Enterococcus faecalis-durans, y a Streptococcus agalactiae, 3 (5.1% a Streptococcus mitis y Streptococcus mitis, 2 (3-4% a Streptococcus bovis y Streptococcus cremoris y 1 (1.7% a Streptococcus salivarius, Streptococcus equinus y Strptococcus sanguis II respectivamente. En todos los casos se observo antecedentes de actuacción medico- quirurjica en el tracto genital, y en el 52.8% de los casos fuô concomitante con el diagnostico clinico-micologico de candidiasis vaginal. La ideittificaccion bacteriologica se realizo mediante el sistema API 20 STREP (sistema api bioMêríeux GmbH, Nütingen, Alemania dando un patron tipico ("excelente identificacción" para el Streptococcus morbillorum.

  12. Gene repertoire evolution of Streptococcus pyogenes inferred from phylogenomic analysis with Streptococcus canis and Streptococcus dysgalactiae.

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    Tristan Lefébure

    Full Text Available Streptococcus pyogenes, is an important human pathogen classified within the pyogenic group of streptococci, exclusively adapted to the human host. Our goal was to employ a comparative evolutionary approach to better understand the genomic events concomitant with S. pyogenes human adaptation. As part of ascertaining these events, we sequenced the genome of one of the potential sister species, the agricultural pathogen S. canis, and combined it in a comparative genomics reconciliation analysis with two other closely related species, Streptococcus dysgalactiae and Streptococcus equi, to determine the genes that were gained and lost during S. pyogenes evolution. Genome wide phylogenetic analyses involving 15 Streptococcus species provided convincing support for a clade of S. equi, S. pyogenes, S. dysgalactiae, and S. canis and suggested that the most likely S. pyogenes sister species was S. dysgalactiae. The reconciliation analysis identified 113 genes that were gained on the lineage leading to S. pyogenes. Almost half (46% of these gained genes were phage associated and 14 showed significant matches to experimentally verified bacteria virulence factors. Subsequent to the origin of S. pyogenes, over half of the phage associated genes were involved in 90 different LGT events, mostly involving different strains of S. pyogenes, but with a high proportion involving the horse specific pathogen S. equi subsp. equi, with the directionality almost exclusively (86% in the S. pyogenes to S. equi direction. Streptococcus agalactiae appears to have played an important role in the evolution of S. pyogenes with a high proportion of LGTs originating from this species. Overall the analysis suggests that S. pyogenes adaptation to the human host was achieved in part by (i the integration of new virulence factors (e.g. speB, and the sal locus and (ii the construction of new regulation networks (e.g. rgg, and to some extent speB.

  13. A Multi-Country Cross-Sectional Study of Vaginal Carriage of Group B Streptococci (GBS and Escherichia coli in Resource-Poor Settings: Prevalences and Risk Factors.

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    Piet Cools

    Full Text Available One million neonates die each year in low- and middle-income countries because of neonatal sepsis; group B Streptococcus (GBS and Escherichia coli are the leading causes. In sub-Saharan Africa, epidemiological data on vaginal GBS and E. coli carriage, a prerequisite for GBS and E. coli neonatal sepsis, respectively, are scarce but necessary to design and implement prevention strategies. Therefore, we assessed vaginal GBS and E. coli carriage rates and risk factors and the GBS serotype distribution in three sub-Saharan countries.A total of 430 women from Kenya, Rwanda and South Africa were studied cross-sectionally. Vaginal carriage of GBS and E. coli, and GBS serotype were assessed using molecular techniques. Risk factors for carriage were identified using multivariable logistic regression analysis.Vaginal carriage rates in reference groups from Kenya and South Africa were 20.2% (95% CI, 13.7-28.7% and 23.1% (95% CI, 16.2-31.9%, respectively for GBS; and 25.0% (95% CI, 17.8-33.9% and 27.1% (95% CI, 19.6-36.2%, respectively for E. coli. GBS serotypes Ia (36.8%, V (26.3% and III (14.0% were most prevalent. Factors independently associated with GBS and E. coli carriage were Candida albicans, an intermediate vaginal microbiome, bacterial vaginosis, recent vaginal intercourse, vaginal washing, cervical ectopy and working as a sex worker. GBS and E. coli carriage were positively associated.Reduced vaginal GBS carriage rates might be accomplished by advocating behavioral changes such as abstinence from sexual intercourse and by avoidance of vaginal washing during late pregnancy. It might be advisable to explore the inclusion of vaginal carriage of C. albicans, GBS, E. coli and of the presence of cervical ectopy in a risk- and/or screening-based administration of antibiotic prophylaxis. Current phase II GBS vaccines (a trivalent vaccine targeting serotypes Ia, Ib, and III, and a conjugate vaccine targeting serotype III would not protect the majority of

  14. Carriage of group B streptococcus in pregnant women from Oxford, UK

    Science.gov (United States)

    Jones, N; Oliver, K; Jones, Y; Haines, A; Crook, D

    2006-01-01

    Objective To investigate asymptomatic vagino‐rectal carriage of group B streptococcus (GBS) in pregnant women. Methods Women in the final trimester of pregnancy were recruited. A single vagino‐rectal swab was taken, with consent, for culture of GBS. Two microbiological methods for isolation of GBS from vagino‐ractal swabs were compared. The distribution of capsular serotypes of the GBS identified was determined. Epidemiological data for a subset (n = 167) of the pregnant women participating were examined. Results 21.3% were colonised vagino‐rectally with GBS. Risk factors for neonatal GBS disease (maternal fever, prolonged rupture of membranes, and preterm delivery) were present in 34 of 167 women (20.4%), and the presence of these factors correlated poorly with GBS carriage. Capsular serotypes III (26.4%), IA (25.8%), V (18.9%), and IB (15.7%) were prevalent in the GBS isolates. Selective broth culture of vagino‐rectal swabs was superior to selective plate culture, but the combination of both methods was associated with increased detection of GBS (7.5%). An algorithm for the identification of GBS from vagino‐rectal swabs was developed. Conclusions GBS carriage is prevalent in pregnant women in Oxfordshire, UK. The poor correlation between risk factors and GBS carriage requires further investigation in larger groups, given that the identification of these surrogate markers is recommended to guide administration of intrapartum antibiotic prophylaxis by the Royal College of Obstetricians of the UK. A selective broth culture detected more GBS carriers than a selective plate culture. PMID:16473927

  15. VNTR analysis reveals unexpected genetic diversity within Mycoplasma agalactiae, the main causative agent of contagious agalactia

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    Ayling Roger D

    2008-11-01

    Full Text Available Abstract Background Mycoplasma agalactiae is the main cause of contagious agalactia, a serious disease of sheep and goats, which has major clinical and economic impacts. Previous studies of M. agalactiae have shown it to be unusually homogeneous and there are currently no available epidemiological techniques which enable a high degree of strain differentiation. Results We have developed variable number tandem repeat (VNTR analysis using the sequenced genome of the M. agalactiae type strain PG2. The PG2 genome was found to be replete with tandem repeat sequences and 4 were chosen for further analysis. VNTR 5 was located within the hypothetical protein MAG6170 a predicted lipoprotein. VNTR 14 was intergenic between the hypothetical protein MAG3350 and the hypothetical protein MAG3340. VNTR 17 was intergenic between the hypothetical protein MAG4060 and the hypothetical protein MAG4070 and VNTR 19 spanned the 5' end of the pseudogene for a lipoprotein MAG4310 and the 3' end of the hypothetical lipoprotein MAG4320. We have investigated the genetic diversity of 88 M. agalactiae isolates of wide geographic origin using VNTR analysis and compared it with pulsed field gel electrophoresis (PFGE and random amplified polymorphic DNA (RAPD analysis. Simpson's index of diversity was calculated to be 0.324 for PFGE and 0.574 for VNTR analysis. VNTR analysis revealed unexpected diversity within M. agalactiae with 9 different VNTR types discovered. Some correlation was found between geographical origin and the VNTR type of the isolates. Conclusion VNTR analysis represents a useful, rapid first-line test for use in molecular epidemiological analysis of M. agalactiae for outbreak tracing and control.

  16. Resistance of Nile tilapia (Oreochromis niloticus) to Streptococcus iniae and S. agalatiae Ib is heritable but not correlated

    Science.gov (United States)

    Tilapia (Oreochromis sp.) are an important source of protein with an ecomonic value approaching US $8 billion yearly. Streptococcal disease, caused by Streptococcus iniae and S. agalactiae (both Gram positive bacteria), is an emerging or re-emerging disease negatively affecting tilapia aquaculture w...

  17. Padronização da técnica de multiplex PCR para a detecção de Staphylococcus aureus, Streptococcus agalactiae e Escherichia coli em amostras de leite bovino, obtidas de tanques de expansão

    OpenAIRE

    Troncarelli, Marcella Zampoli [UNESP

    2011-01-01

    Com o objetivo de normatizar a cadeia produtiva visando à melhoria da qualidade do leite no Brasil, o MAPA delineou a IN n° 51, em vigor desde julho de 2005. Em linha com estes parâmetros, objetivou-se, no presente estudo, padronizar o método de mPCR para a detecção de S. aureus, S. agalactiae e E. coli em amostras de leite bovino obtidas de tanques de expansão, e avaliar esta técnica como possível recurso diagnóstico a ser empregado em programas de controle de qualidade do leite oferecido pa...

  18. Group B streptococcus colonization and HIV in pregnancy: A cohort study in Nigeria.

    Science.gov (United States)

    Biobaku Oluwafunmilola, R; Olaleye Atinuke, O; Adefusi Olorunwa, F; Adeyemi Babalola, A; Onipede Anthony, O; Loto Olabisi, M; Imaralu John, O

    2017-01-01

    Group B streptococcus (GBS) is a leading cause of maternal and neonatal infectious morbidity. HIV is prevalent among pregnant women in Nigeria. To determine the rates of anogenital GBS colonization in our institution and compare GBS colonization rates between HIV positive and negative pregnant women. A cross-sectional comparative study was conducted over 6 months. Patients were separated according to their HIV status: positive and negative. GBS colonization was assessed by vaginal and anal swabs collected at 35-37 weeks of gestation and cultured in Todd-Hewitt broth, followed by a confirmatory test. Socio-demographic characteristics and CD4 count were extracted from patient medical records. Secondary outcomes were identification of risk factors for GBS colonization, antibiotic sensitivity, and any association between CD4 count and GBS colonization. Appropriate statistical analysis was done. A total of 200 patients attended the clinic; 67 HIV positive and 133 negative. Analyzed samples were 198; the overall prevalence of GBS was 18.2%. No significant difference in GBS colonization was noted between HIV positive (19.4% [13]) and negative patients (17.6% [23/131]). Most GBS isolates were susceptible to ampicillin (87%) and penicillin (81%). A high body mass index (BMI) was independently associated with GBS colonization (OR = 1.25, 95% CI: 1.04-1.51). No association was observed between CD4 counts and GBS colonization. A high prevalence of GBS colonization was observed in our institution. Colonization rates were independent of the HIV status but associated with a high BMI in HIV positive women.

  19. The group B streptococcal alpha C protein binds alpha1beta1-integrin through a novel KTD motif that promotes internalization of GBS within human epithelial cells.

    Science.gov (United States)

    Bolduc, Gilles R; Madoff, Lawrence C

    2007-12-01

    Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis and meningitis among neonates and a cause of morbidity among pregnant women and immunocompromised adults. GBS epithelial cell invasion is associated with expression of alpha C protein (ACP). Loss of ACP expression results in a decrease in GBS internalization and translocation across human cervical epithelial cells (ME180). Soluble ACP and its 170 amino acid N-terminal region (NtACP), but not the repeat protein RR', bind to ME180 cells and reduce internalization of wild-type GBS to levels obtained with an ACP-deficient isogenic mutant. In the current study, ACP colocalized with alpha(1)beta(1)-integrin, resulting in integrin clustering as determined by laser scanning confocal microscopy. NtACP contains two structural domains, D1 and D2. D1 is structurally similar to fibronectin's integrin-binding region (FnIII10). D1's (KT)D146 motif is structurally similar to the FnIII10 (RG)D1495 integrin-binding motif, suggesting that ACP binds alpha(1)beta(1)-integrin via the D1 domain. The (KT)D146A mutation within soluble NtACP reduced its ability to bind alpha(1)beta(1)-integrin and inhibit GBS internalization within ME180 cells. Thus ACP binding to human epithelial cell integrins appears to contribute to GBS internalization within epithelial cells.

  20. Organization of the capsule biosynthesis gene locus of the oral streptococcus Streptococcus anginosus.

    Science.gov (United States)

    Tsunashima, Hiroyuki; Miyake, Katsuhide; Motono, Makoto; Iijima, Shinji

    2012-03-01

    The capsular polysaccharide (CPS) of the important oral streptococcus Streptococcus anginosus, which causes endocarditis, and the genes for its synthesis have not been clarified. In this study, we investigated the gene locus required for CPS synthesis in S. anginosus. Southern hybridization using the cpsE gene of the well-characterized bacterium S. agalactiae revealed that there is a similar gene in the genome of S. anginosus. By using the colony hybridization technique and inverse PCR, we isolated the CPS synthesis (cps) genes of S. anginosus. This gene cluster consisted of genes containing typical regulatory genes, cpsA-D, and glycosyltransferase genes coding for glucose, rhamnose, N-acetylgalactosamine, and galactofuranose transferases. Furthermore, we confirmed that the cps locus is required for CPS synthesis using a mutant strain with a defective cpsE gene. The cps cluster was found to be located downstream the nrdG gene, which encodes ribonucleoside triphosphate reductase activator, as is the case in other oral streptococci such as S. gordonii and S. sanguinis. However, the location of the gene cluster was different from those of S. pneumonia and S. agalactiae. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  1. 40 Gb/s optical transmission systems

    DEFF Research Database (Denmark)

    Buxens Azcoaga, Alvaro Juan; Nielsen, Steen Krogh

    2003-01-01

    ; chromatic dispersion, Polarization Mode Dispersion (PMD), Self Phase Modulation (SPM) and linear or non-linear crosstalk among others. Regarding chromatic dispersion, sufficient evidence is presented for the need in 40 Gb/s systems of either modulation formats that allow for higher tolerance than....... Using a 9 ps pulsed RZ Tx, transmission is achieved over a 400 km link consisting of 5 spans of 80 km standard-SMF with a Quality (Q) factor of 17.7 dB, while for NRZ it is reduced to 15 dB. In another experimental verification over 40 km spans of standard-SMF, we could achieve transmission over 6 spans...

  2. Contagious agalactia by Mycoplasma agalactiae in small ruminants in Brazil: first report Agalaxia contagiosa por Mycoplasma agalactiae em pequenos ruminantes no Brasil: primeiro relato

    Directory of Open Access Journals (Sweden)

    Edisio Oliveira de Azevedo

    2006-12-01

    Full Text Available Two outbreaks of contagious agalactia by Mycoplasma agalactiae occurred in Paraíba State, Northeastern Region of Brazil are reported. The disease was characterized by mastitis, agalactia and polyarthritis in does and polyarthritis and conjunctivitis in kids and lambs. Fever and anorexia were also observed. Morbidy was from 26.1% to 100% in does, 36.5 to 100% in kids and 49% in lambs. In one farm 14.3% of the lactating goats and 6.4% of the kids died or were euthanized. In the other, 3.3% of the does, 36.5% of the kids and 22.9% of the lambs died and 84 affected goats were euthanized to control the disease. M. agalactiae was isolated from milk, joint exudates, nasal swabs and ear washings. The colonies were characteristic of Mycoplasma and the agent did not ferment both glucose and arginin. It was typed as Mycoplasma agalactiae by immunoperoxidase and PCR. This is the first report of M. agalactiae infection in Brazil, but the source of the infection remains unknown.Dois surtos de agalaxia contagiosa causada por Mycoplasma agalactiae são descritos no Estado da Paraíba, região Nordeste do Brasil. A doença caracterizou-se por mastite, agalaxia e poliartrite em cabras e poliartrite e cerato-conjuntivite em cabritos e cordeiros. Febre e anorexia também foram observadas. A morbidade variou de 26,1% a 100% nas cabras, 36,5% a 100% em cabritos e 49,0% em cordeiros. Na primeira fazenda, 14,3% das cabras em lactação e 6,4% dos cabritos morreram ou foram sacrificados. Na outra propriedade, 3,3% dos caprinos adultos, 36,5% dos cabritos e 22,9% dos cordeiros morreram e outros 84 caprinos foram sacrificados para controle da doença. M. agalactiae foi isolado a partir de leite, líquido articular, suabe nasal e lavado do conduto auditivo externo. Colônias características de Mycoplasma e que não fermentaram a glicose e arginina foram observadas. A identificação de M. agalactiae foi realizada por imunoperoxidase indireta e PCR. Sendo assim, M

  3. Streptococcus suis

    DEFF Research Database (Denmark)

    Poggenborg, René; Gaïni, Shahin; Kjaeldgaard, Poul

    2008-01-01

    Meningitis and spondylodiscitis caused by Streptococcus suis is a rare disease which is contracted by occupational exposure to pigs. We report a 54-y-old pig-farm worker with S. suis meningitis and septicaemia complicated with thoracal and lumbar spine spondylodiscitis. The S. suis strain involved...

  4. 100 Gb/s single VCSEL data transmission link

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Estaran Tolosa, Jose Manuel; Li, Bomin

    2012-01-01

    100 Gb/s optical fiber transmission link with a single 1.5 um VCSEL has been experimentally demonstrated using 4-level pulse amplitude modulation.......100 Gb/s optical fiber transmission link with a single 1.5 um VCSEL has been experimentally demonstrated using 4-level pulse amplitude modulation....

  5. Maternal Colonization With Group B Streptococcus and Serotype Distribution Worldwide: Systematic Review and Meta-analyses.

    Science.gov (United States)

    Russell, Neal J; Seale, Anna C; O'Driscoll, Megan; O'Sullivan, Catherine; Bianchi-Jassir, Fiorella; Gonzalez-Guarin, Juan; Lawn, Joy E; Baker, Carol J; Bartlett, Linda; Cutland, Clare; Gravett, Michael G; Heath, Paul T; Le Doare, Kirsty; Madhi, Shabir A; Rubens, Craig E; Schrag, Stephanie; Sobanjo-Ter Meulen, Ajoke; Vekemans, Johan; Saha, Samir K; Ip, Margaret

    2017-11-06

    Maternal rectovaginal colonization with group B Streptococcus (GBS) is the most common pathway for GBS disease in mother, fetus, and newborn. This article, the second in a series estimating the burden of GBS, aims to determine the prevalence and serotype distribution of GBS colonizing pregnant women worldwide. We conducted systematic literature reviews (PubMed/Medline, Embase, Latin American and Caribbean Health Sciences Literature [LILACS], World Health Organization Library Information System [WHOLIS], and Scopus), organized Chinese language searches, and sought unpublished data from investigator groups. We applied broad inclusion criteria to maximize data inputs, particularly from low- and middle-income contexts, and then applied new meta-analyses to adjust for studies with less-sensitive sampling and laboratory techniques. We undertook meta-analyses to derive pooled estimates of maternal GBS colonization prevalence at national and regional levels. The dataset regarding colonization included 390 articles, 85 countries, and a total of 299924 pregnant women. Our adjusted estimate for maternal GBS colonization worldwide was 18% (95% confidence interval [CI], 17%-19%), with regional variation (11%-35%), and lower prevalence in Southern Asia (12.5% [95% CI, 10%-15%]) and Eastern Asia (11% [95% CI, 10%-12%]). Bacterial serotypes I-V account for 98% of identified colonizing GBS isolates worldwide. Serotype III, associated with invasive disease, accounts for 25% (95% CI, 23%-28%), but is less frequent in some South American and Asian countries. Serotypes VI-IX are more common in Asia. GBS colonizes pregnant women worldwide, but prevalence and serotype distribution vary, even after adjusting for laboratory methods. Lower GBS maternal colonization prevalence, with less serotype III, may help to explain lower GBS disease incidence in regions such as Asia. High prevalence worldwide, and more serotype data, are relevant to prevention efforts. © The Author 2017. Published by

  6. HIV positive patient with GBS-like syndrome.

    Science.gov (United States)

    Shepherd, Samantha J; Black, Heather; Thomson, Emma C; Gunson, Rory N

    2017-08-01

    Introduction. Guillain-Barré Syndrome (GBS) is an acute demyelinating polyneuropathy which can occur post-infection. Criteria of diagnosis of GBS include areflexia with progressive bilateral weakness in arms and legs. GBS can lead to severe respiratory and cardiac complications. The fatality rate can be up to 5 % in patients, depending on the severity of the symptoms. HIV can cause a range of neurological disorders including, on rare occasions, GBS. GBS can occur at any stage of HIV infection, highlighting the complexity of diagnosis of GBS within HIV patients. Case presentation. A 57 year old female with lumbar back pain radiating to the legs, poor mobility and tiredness, with reports of a viral-like illness four days previously, was initially diagnosed with a lower respiratory tract infection and discharged. Seventeen days later the patient was readmitted to hospital with progressive lower and upper limb weakness, areflexia and sensory loss. She was diagnosed with GBS and was unexpectedly discovered to be HIV-positive. HIV avidity was low indicating a recently acquired HIV infection. The patient was treated with intravenous immunoglobulin for five days for the GBS and commenced antriretrovirals for HIV. The patient was discharge from hospital 53 days after admission with walking aids and regular physiotherapy follow-up. . This case highlighted the need for all clinicians to be aware that patients with symptoms of GBS, regardless of clinical history should be offered an HIV test. GBS can be the first sign a patient is HIV-positive.

  7. A hemolytic pigment of Group B Streptococcus allows bacterial penetration of human placenta

    Science.gov (United States)

    Whidbey, Christopher; Harrell, Maria Isabel; Burnside, Kellie; Ngo, Lisa; Becraft, Alexis K.; Iyer, Lakshminarayan M.; Aravind, L.; Hitti, Jane

    2013-01-01

    Microbial infection of the amniotic fluid is a significant cause of fetal injury, preterm birth, and newborn infections. Group B Streptococcus (GBS) is an important human bacterial pathogen associated with preterm birth, fetal injury, and neonatal mortality. Although GBS has been isolated from amniotic fluid of women in preterm labor, mechanisms of in utero infection remain unknown. Previous studies indicated that GBS are unable to invade human amniotic epithelial cells (hAECs), which represent the last barrier to the amniotic cavity and fetus. We show that GBS invades hAECs and strains lacking the hemolysin repressor CovR/S accelerate amniotic barrier failure and penetrate chorioamniotic membranes in a hemolysin-dependent manner. Clinical GBS isolates obtained from women in preterm labor are hyperhemolytic and some are associated with covR/S mutations. We demonstrate for the first time that hemolytic and cytolytic activity of GBS is due to the ornithine rhamnolipid pigment and not due to a pore-forming protein toxin. Our studies emphasize the importance of the hemolytic GBS pigment in ascending infection and fetal injury. PMID:23712433

  8. Group B streptococcus detection in China: comparison of different screening methods and different sampling sites

    Directory of Open Access Journals (Sweden)

    Xi Wang, Yingna Song, Liangkun Ma, Juntao Liu, Yingchun Xu, Jie Yi

    2016-12-01

    Full Text Available Objectives: To evaluate the use of real-time polymerase chain reaction (RT-PCR and bacterial culture methods to detect group B streptococcus (GBS in Chinese pregnant women in the third trimester; to separately assess the prevalence of rectal and vaginal GBS colonization ; and to determine the antimicrobial susceptibility pattern of the isolates. Methodology: Samples were collected from 505 women at 35 and 37 weeks gestation at the Peking Union Medical College Hospital. Bacterial culture and RT-PCR were performed. Antimicrobial susceptibility to commonly used antibiotics was also analyzed. Results: The overall GBS colonization rate was 7.5%. The colonization rate, sensitivity, and negative predictive value of the bacterial culture method were 2.8%, 36.8%, and 95.1%, respectively, and these values were 7.3%, 97.4%, and 99.8%, respectively, for PCR (p<0.001. The GBS colonization rate of the rectum (6.7% was higher than that of the vagina (2.8% (p=0.005. Antimicrobial susceptibility testing showed that 100% were sensitive to penicillin, cephalosporin and vancomycin. Conclusions: RT-PCR was found to be a rapid and sensitive test for the detection of GBS colonization in Chinese pregnant women. Rectal swabbing was also important for detecting GBS colonization. β-lactams are the first-line antibiotics used for the treatment of GBS. J Microbiol Infect Dis 2016;6(4: 179-183

  9. The sensitivity to antibiotics of strains of group B streptococcus isolates from pregnant women in Belgrade

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    Jovanović Luka

    2016-01-01

    Full Text Available Introduction: Group B streptococcus (GBS is a significant human pathogen. GBS colonizes the vagina and it is one of the most important causes of early neonatal sepsis and meningitis. In many countries, screening of pregnant women and intrapartal use of antibiotics are common practice. Macrolide and lincosamide resistant strains of GBS are a significant problem, because these antibiotics are the second line therapy in case of penicillin allergy. Aim: Our aim was to investigate the frequency of antibiotic resistant strains of GBS and to detect macrolide resistance phenotypes in GBS strains obtained from pregnant women in Belgrade. Material and Methods: 105 GBS isolates were obtained from vaginal swabs of pregnant women attending two Gynecology and Obstetrics Centers in Belgrade. The isolates were tested for antimicrobial susceptibility pattern and D test were performed on Mueller Hinton agar. Results: Macrolide and lincosamide resistance was found in 30.4 %, and 23.8 % of isolates, respectively. There was a high frequency of tetracycline resistant strains (88.6 %. Most frequent macrolide resistant phenotype was iMLSb (macrolide and inducibile lincosamide resistance (62.4%. Conclusion: The results of our study indicate that there is a high level of macrolide resistance among GBS isolates in Serbia and the active surveillance is needed.

  10. Performance of Hitchens-Pike-Todd-Hewitt medium for group B streptococcus screening in pregnant women.

    Directory of Open Access Journals (Sweden)

    Simone Cristina Castanho Sabaini de Melo

    Full Text Available Group B streptococcus (GBS, which commonly colonizes the female genital tract and rectum, can cause infections in newborns with varying severity, possibly leading to death. The aim of the present study was to evaluate Hitchens-Pike-Todd-Hewitt (HPTH medium performance for GBS screening in pregnant women. A descriptive analytical cross-sectional study was performed with 556 pregnant women, of which 496 were at 35-37 weeks of gestation and 60 were at ≥ 38 weeks of gestation. The study was conducted from September 2011 to March 2014 in northern Paraná, Brazil. Vaginal and anorectal clinical specimens from each pregnant woman were plated on sheep blood agar (SBA and seeded on HPTH medium and Todd-Hewitt enrichment broth. Of the 496 pregnant women at 35-37 weeks of gestation, 141 (28.4% were positive for GBS, based on the combination of the three culture media and clinical specimens. The GBS colonization rates that were detected by each medium were 22.2% for HPTH medium, 21.2% for SBA, and 13.1% for Todd-Hewitt enrichment broth. Of the 60 pregnant women at ≥ 38 weeks of gestation, seven (11.7% were positive for GBS. These results demonstrate that HPTH medium and SBA were more sensitive than Todd-Hewitt enrichment broth for GBS screening in pregnant women and good GBS recovery in culture, indicating that the two media should be used together for vaginal and anorectal specimens.

  11. Mixed infection zones may be important in the epidemiology of contagious agalactia

    Directory of Open Access Journals (Sweden)

    Jafarizadeh Amirreza

    2016-06-01

    Full Text Available Introduction: The current study was designed to detect Mycoplasma agalactiae (Ma, Mycoplasma mycoides subsp. capri (Mmc, Mycoplasma capricolum subsp. capricolum (Mcc and Mycoplasma putrefaciens (Mp in sheep and goats with clinical signs consistent with contagious agalactia.

  12. Streptococcus agalactie como agente etiológico de Doença Sexualmente Transmissível Streptococcus agalactie involved in the etiology of Sexually Transmitted Diseases

    Directory of Open Access Journals (Sweden)

    Marcos Noronha Frey

    2011-12-01

    Full Text Available O Streptococcus agalactie é um importante micro-organismo causador de doenças em gestantes, neonatos, idosos (maiores de 65 anos de idade, e portadores de doenças crônicas debilitantes, sendo um patógeno incomum em pacientes que não se enquadrem nestas faixas etárias ou perfil clínico (1-5, e, raramente, é descrito como agente causador de doenças sexualmente transmissíveis. Descrevemos o caso de um adulto jovem hígido de 19 anos, apresentando lesões ulceradas genitais e oral, assim como corrimento uretral e ocular, sugestivas de terem sido causadas pelo Streptococcus agalactie, e adquiridas através do contato sexual (doenças sexualmente transmissíveis.Streptococcus agalactiae is an important microorganism involved in a number of conditions in pregnant women, newborns, elderly people (over 65 years of age and individuals with chronic disabling illnesses. This pathogen is infrequently found among patients outside this age range or clinical profile(1-5 and is rarely reported in the etiology of sexually transmitted diseases. Here we describe a case of an otherwise healthy 19 year-old male, who presented with ulcerative genital and oral lesions in association with urethral and ocular discharge, suggestive of Streptococcus agalactiae infection acquired through sexual contact.

  13. Increased risk of Group B Streptococcus invasive infection in HIV-exposed but uninfected infants : a review of the evidence and possible mechanisms

    Directory of Open Access Journals (Sweden)

    NICOLAS DAUBY

    2016-11-01

    Full Text Available Group B streptococcus (GBS is a major cause of neonatal sepsis and mortality worldwide. Studies from both developed and developing countries have shown that HIV exposed but uninfected (HEU infants are at increased risk of infectious morbidity, as compared to HIV unexposed uninfected infants (HUU. A higher susceptibility to GBS infections has been reported in HEU infants, particularly late-onset diseases (LOD and more severe manifestations of GBS diseases. We review here the possible explanations for increased susceptibility to GBS infection. Maternal GBS colonization during pregnancy is a major risk factor for early-onset GBS invasive disease but colonization rates are not higher in HIV-infected compared to HIV-uninfected pregnant women, while selective colonization with more virulent strains in HIV-infected women is suggested in some studies. Lower serotype specific GBS maternal antibody transfer and quantitative and qualitative defects of innate immune responses in HEU infants may play a role in the increased risk of GBS invasive disease. The impact of maternal antiretroviral treatment and its consequences on immune activation in HEU newborns is important to study. Maternal immunization presents a promising intervention to reduce GBS burden in the growing HEU population.

  14. Oral Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 to reduce Group B Streptococcus colonization in pregnant women: A randomized controlled trial.

    Science.gov (United States)

    Ho, Ming; Chang, Yin-Yi; Chang, Wei-Chun; Lin, Hung-Chih; Wang, Mei-Hung; Lin, Wu-Chou; Chiu, Tsan-Hung

    2016-08-01

    This study is to examine the effect of Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 taken orally before bedtime on Group B Streptococcus (GBS)-positive pregnant women with respect to becoming GBS negative. In total, 110 pregnant women at 35-37 weeks of gestation who were diagnosed by GBS culture as being GBS positive for both vaginal and rectal GBS colonization were randomly assigned to be orally treated with two placebo capsules or two probiotic capsules (containing L. rhamnosus GR-1 and L. reuteri RC-14) before bedtime until delivery. All women were tested for vaginal and rectal GBS colonization again by GBS culture on admission for delivery. Of the 110 participants, 99 completed the study (49 in the probiotic group and 50 in the placebo group). The GBS colonization results changed from positive to negative in 21 women in the probiotic group (42.9%) and in nine women in the placebo group (18.0%) during this period (Chi-square p=0.007). Oral probiotic containing L. rhamnosus GR-1 and L. reuteri RC-14 could reduce the vaginal and rectal GBS colonization rate in pregnant women. Copyright © 2016. Published by Elsevier B.V.

  15. Guillain-Barré Syndrome (GBS) and Flu Vaccine

    Science.gov (United States)

    ... Swine Variant Pandemic Other Guillain-Barré syndrome and Flu Vaccine Questions & Answers Language: English (US) Español Recommend ... it among people who have been vaccinated against flu? The background rate for GBS in the Unites ...

  16. Characterization of the duodenase-1 gene and its associations with resistance to Streptococuus agalactiae in hybrid tilapia (Oreochromis spp.).

    Science.gov (United States)

    Shen, Yubang; Fu, Gui Hong; Liu, Feng; Yue, Gen Hua

    2015-08-01

    Tilapia is a group of cultured teleost fishes whose production is threatened by some diseases. Identification of DNA markers associated with disease resistance in candidate genes may facilitate to accelerate the selection of disease resistance. The gene encoding a duodenase, which can trigger immune response, has not been studied in fish. We characterized the cDNA of duodenase-1 gene of hybrid tilapia. Its ORF is 759 bp, encoding a serine protease of 252 amino acids. This gene consisted of five exons and four introns. Its expression was detected in all 10 tissues examined, and it was highly expressed in the intestine and kidney. After a challenge with the bacterial pathogen, Streptococcus agalactiae, its expression was up-regulated significantly in the intestine, liver and spleen. We identified seven SNPs in the gene and found that four of them were significantly associated with the resistance to S. agalactiae (P tilapia. The SNP markers in the duodenase-1 gene associated with resistance to the bacterial pathogen, may facilitate the selection of tilapia resistant to the bacterial disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Recognition of Streptococcus pseudoporcinus Colonization in Women as a Consequence of Using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Group B Streptococcus Identification.

    Science.gov (United States)

    Suwantarat, Nuntra; Grundy, Maureen; Rubin, Mayer; Harris, Renee; Miller, Jo-Anne; Romagnoli, Mark; Hanlon, Ann; Tekle, Tsigereda; Ellis, Brandon C; Witter, Frank R; Carroll, Karen C

    2015-12-01

    During a 14-month period of using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for group B streptococcus (GBS) identification, we recovered 32 (1%) Streptococcus pseudoporcinus isolates from 3,276 GBS screening cultures from female genital sources (25 isolates from pregnant women and 7 from nonpregnant women). An additional two S. pseudoporcinus isolates were identified from a urine culture and a posthysterectomy wound culture. These isolates were found to cross-react with three different GBS antigen agglutination kits, PathoDx (Remel) (93%), Prolex (Pro-Lab Diagnostics) (38%), and Streptex (Remel) (53%). New approaches to bacterial identification in routine clinical microbiology laboratories may affect the prevalence of S. pseudoporcinus. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  18. Diversity and composition of vaginal microbiota of pregnant women at risk for transmitting Group B Streptococcus treated with intrapartum penicillin.

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    Luiz Fernando Wurdig Roesch

    Full Text Available Administering intravenous antibiotics during labor to women at risk for transmitting Group B Streptococcus (GBS can prevent infections in newborns. However, the impact of intrapartum antibiotic prophylaxis on mothers' microbial community composition is largely unknown. We compared vaginal microbial composition in pregnant women experiencing preterm birth at ≤ 32 weeks gestation that received intrapartum antibiotic prophylaxis with that in controls.Microbiota in vaginal swabs collected shortly before delivery from GBS positive women that received penicillin intravenously during labor or after premature rupture of membranes was compared to controls. Microbiota was analyzed by 16S rRNA sequencing using the PGM Ion Torrent to determine the effects of penicillin use during hospitalization and GBS status on its composition.Penicillin administration was associated with an altered vaginal microbial community composition characterized by increased microbial diversity. Lactobacillus sp. contributed only 13.1% of the total community in the women that received penicillin compared to 88.1% in the controls. Streptococcus sp. were present in higher abundance in GBS positive woman compared to controls, with 60% of the total vaginal microbiota in severe cases identified as Streptococcus sp.Vaginal communities of healthy pregnant women were dominated by Lactobacillus sp. and contained low diversity, while Group B Streptococcus positive women receiving intrapartum antibiotic prophylaxis had a modified vaginal microbiota composition with low abundance of Lactobacillus but higher microbial diversity.

  19. Diversity and composition of vaginal microbiota of pregnant women at risk for transmitting Group B Streptococcus treated with intrapartum penicillin.

    Science.gov (United States)

    Roesch, Luiz Fernando Wurdig; Silveira, Rita C; Corso, Andréa L; Dobbler, Priscila Thiago; Mai, Volker; Rojas, Bruna S; Laureano, Álvaro M; Procianoy, Renato S

    2017-01-01

    Administering intravenous antibiotics during labor to women at risk for transmitting Group B Streptococcus (GBS) can prevent infections in newborns. However, the impact of intrapartum antibiotic prophylaxis on mothers' microbial community composition is largely unknown. We compared vaginal microbial composition in pregnant women experiencing preterm birth at ≤ 32 weeks gestation that received intrapartum antibiotic prophylaxis with that in controls. Microbiota in vaginal swabs collected shortly before delivery from GBS positive women that received penicillin intravenously during labor or after premature rupture of membranes was compared to controls. Microbiota was analyzed by 16S rRNA sequencing using the PGM Ion Torrent to determine the effects of penicillin use during hospitalization and GBS status on its composition. Penicillin administration was associated with an altered vaginal microbial community composition characterized by increased microbial diversity. Lactobacillus sp. contributed only 13.1% of the total community in the women that received penicillin compared to 88.1% in the controls. Streptococcus sp. were present in higher abundance in GBS positive woman compared to controls, with 60% of the total vaginal microbiota in severe cases identified as Streptococcus sp. Vaginal communities of healthy pregnant women were dominated by Lactobacillus sp. and contained low diversity, while Group B Streptococcus positive women receiving intrapartum antibiotic prophylaxis had a modified vaginal microbiota composition with low abundance of Lactobacillus but higher microbial diversity.

  20. Regulation of virulence by a two-component system in group B streptococcus.

    Science.gov (United States)

    Jiang, Sheng-Mei; Cieslewicz, Michael J; Kasper, Dennis L; Wessels, Michael R

    2005-02-01

    Group B Streptococcus (GBS) is frequently carried in the gastrointestinal or genitourinary tract as a commensal organism, yet it has the potential to cause life-threatening infection in newborn infants, pregnant women, and individuals with chronic illness. Regulation of virulence factor expression may affect whether GBS behaves as an asymptomatic colonizer or an invasive pathogen, but little is known about how such factors are controlled in GBS. We now report the characterization of a GBS locus that encodes a two-component regulatory system similar to CsrRS (or CovRS) in Streptococcus pyogenes. Inactivation of csrR, encoding the putative response regulator, in two unrelated wild-type strains of GBS resulted in a marked increase in production of beta-hemolysin/cytolysin and a striking decrease in production of CAMP factor, an unrelated cytolytic toxin. Quantitative RNA hybridization experiments revealed that these two phenotypes were associated with a marked increase and decrease in expression of the corresponding genes, cylE and cfb, respectively. The CsrR mutant strains also displayed increased expression of scpB encoding C5a peptidase. Similar, but less marked, changes in gene expression were observed in CsrS (putative sensor component) mutants, evidence that CsrR and CsrS constitute a functional two-component system. Experimental infection studies in mice demonstrated reduced virulence of both CsrR and CsrS mutant strains relative to the wild type. Together, these results indicate that CsrRS regulates expression of multiple GBS virulence determinants and is likely to play an important role in GBS pathogenesis.

  1. Colonização materna e neonatal por estreptococo do grupo B em situações de ruptura pré-termo de membranas e no trabalho de parto prematuro Group B streptococcus maternal and neonatal colonization in preterm rupture of membranes and preterm labor

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    Marcelo Luís Nomura

    2009-08-01

    dois casos de sepse precoce por EGB nesta amostra, com prevalência de 10,8 casos por mil nascidos vivos e mortalidade de 50%. CONCLUSÕES: a amostra avaliada apresenta altas taxas de colonização materna por Streptococcus agalactiae. São necessários o uso de meio de cultura seletivo e a associação de culturas ano-retais e vaginais para aumentar a taxa de detecção do EGB. A incidência de sepse neonatal precoce foi elevada nesta população.PURPOSE: to indentify the prevalence and risk factors of maternal colonization by group B streptococcus (GBS in pregnant women with premature labor (PL and/or premature membrane rupture (PMR. METHODS: two anal and two vaginal swabs were collected from 203 pregnant women with diagnosis of PL or PMR assisted at the practice along one year. Pregnant women with imminent labor at admission were excluded. One swab of each source was placed in a transfer milieu and sent for culture in blood-agar plates; the two remaining swabs were incubated for 24 hours in Todd-Hewitt milieu for further sowing in blood-agar plates. Risk factors were analyzed by the chi-square test, Student's t-test (p-value set at 0.05 and 95% confidence interval and logistic regression. The following variables were analyzed: age, race, parity and mother schooling; culture results by source and type of culture; admission diagnosis; gestational age at admission; asymptomatic bacteriuria; gestational age at delivery; type of delivery; neonatal GBS colonization rate and immediate neonatal condition. RESULTS: prevalence of maternal GBS colonization was 27.6% (56 cases. The colonization rates according to gestational complications were 30% for PMR, 25.2% for PL and 17.8% for PL + PMR. Univariate analysis has shown that the variables Caucasian race, low level of schooling and bacteriuria were associated with higher colonization rates. Multivariate analysis showed that the presence of urinary infection was the only variable associated with maternal colonization. The GBS

  2. Group B streptococcus exploits vaginal epithelial exfoliation for ascending infection.

    Science.gov (United States)

    Vornhagen, Jay; Armistead, Blair; Santana-Ufret, Verónica; Gendrin, Claire; Merillat, Sean; Coleman, Michelle; Quach, Phoenicia; Boldenow, Erica; Alishetti, Varchita; Leonhard-Melief, Christina; Ngo, Lisa Y; Whidbey, Christopher; Doran, Kelly S; Curtis, Chad; Waldorf, Kristina M Adams; Nance, Elizabeth; Rajagopal, Lakshmi

    2018-04-09

    Thirteen percent of pregnancies result in preterm birth or stillbirth, accounting for fifteen million preterm births and three and a half million deaths annually. A significant cause of these adverse pregnancy outcomes is in utero infection by vaginal microorganisms. To establish an in utero infection, vaginal microbes enter the uterus by ascending infection; however, the mechanisms by which this occurs are unknown. Using both in vitro and murine models of vaginal colonization and ascending infection, we demonstrate how a vaginal microbe, group B streptococcus (GBS), which is frequently associated with adverse pregnancy outcomes, uses vaginal exfoliation for ascending infection. GBS induces vaginal epithelial exfoliation by activation of integrin and β-catenin signaling. However, exfoliation did not diminish GBS vaginal colonization as reported for other vaginal microbes. Rather, vaginal exfoliation increased bacterial dissemination and ascending GBS infection, and abrogation of exfoliation reduced ascending infection and improved pregnancy outcomes. Thus, for some vaginal bacteria, exfoliation promotes ascending infection rather than preventing colonization. Our study provides insight into mechanisms of ascending infection by vaginal microbes.

  3. Bilateral Necrotizing Fasciitis of the Foot Associated with Group B Streptococcus

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    Keitaro Fukuda

    2016-09-01

    Full Text Available Necrotizing fasciitis (NF is a severe bacterial infection involving fascia and subcutaneous tissue. It generally affects upper or lower extremities unilaterally, and there are few reports of bilateral-extremity NF. Here, we report a case of a 43-year-old male with type 1 diabetes who had NF on the left foot and subsequently developed NF on the other foot 1 week later. The patient survived with antimicrobial therapy and bilateral below-knee amputation. As group B streptococcus (GBS was isolated by blood culture and culture of excised tissues of both feet, bilateral GBS NF of the foot was diagnosed. GBS is a rare causative pathogen in NF; however, there have been two case reports of bilateral GBS NF of an extremity in which NF appeared on the opposite extremity 1 week after the primary site infection, as in our case. GBS was isolated from cultures of blood and excised tissues of both extremities in both cases. Together, these observations suggest that GBS has a potential to cause secondary NF at remote sites by hematogenous dissemination with approximately 1 week delay and thereby lead to bilateral NF.

  4. Bacteriuria with group B streptococcus and preterm birth

    DEFF Research Database (Denmark)

    Khalil, M. R.; Uldbjerg, N.; Thorsen, P.

    2015-01-01

    Objectives: Preterm delivery (PTD) contributes to 70% of all perinatal deaths and nearly 50% of permanent neurological damages in children. Treatment and follow-up to prevent recolonization in pregnant women with Group B Streptococcus (GBS) in the urine may reduce the frequency of PTD....... In a Cochrane review, the incidence of low birth weight infants was reduced, however, not for PTD. The association between asymptomatic bacteriuria during pregnancy and PTD remains controversial. The objective of this study was to investigate whether there is an association between GBS bacteriuria (BU......) in pregnancy and PTD. Method: A retrospective population-based cohort consisting of 36,097 pregnant women from Hospital Lillebaelt area, Denmark, during January 2002-December 2012, of whom 37.2% (equivalent to 13,417) have undergone culture of their urine at the Department of Clinical Microbiology. Information...

  5. Detection of Group B Streptococcus in Brazilian pregnant women and antimicrobial susceptibility patterns

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    Didier Silveira Castellano-Filho

    2010-12-01

    Full Text Available Group B Streptococcus (GBS is still not routinely screened during pregnancy in Brazil, being prophylaxis and empirical treatment based on identification of risk groups. This study aimed to investigate GBS prevalence in Brazilian pregnant women by culture or polymerase chain reaction (PCR associated to the enrichment culture, and to determine the antimicrobial susceptibility patterns of isolated bacteria, so as to support public health policies and empirical prophylaxis. After an epidemiological survey, vaginal and anorectal specimens were collected from 221 consenting laboring women. Each sample was submitted to enrichment culture and sheep blood agar was used to isolate suggestive GBS. Alternatively, specific PCR was performed from enrichment cultures. Antimicrobial susceptibility patterns were determined for isolated bacteria by agar diffusion method. No risk groups were identified. Considering the culture-based methodology, GBS was detected in 9.5% of the donors. Twenty five bacterial strains were isolated and identified. Through the culture-PCR methodology, GBS was detected in 32.6% specimens. Bacterial resistance was not detected against ampicillin, cephazolin, vancomycin and ciprofloxacin, whereas 22.7% were resistant to erythromycin and 50% were resistant to clindamycin. GBS detection may be improved by the association of PCR and enrichment culture. Considering that colony selection in agar plates may be laboring and technician-dependent, it may not reflect the real prevalence of streptococci. As in Brazil prevention strategies to reduce the GBS associated diseases have not been adopted, prospective studies are needed to anchor public health policies especially considering the regional GBS antimicrobial susceptibility patterns.

  6. Effect of Bacteriocin-like Inhibitory Substances Produced by Vaginal ...

    African Journals Online (AJOL)

    Reduction of vaginal Lactobacillus population leads to overgrowth of opportunistic organisms such as Streptococcus agalactiae (Group B Streptococcus, GBS), which causes life threatening neonatal infections. The activities of bacteriocin-like inhibitory substances (BLIS) produced by Lactobacillus species isolated from the ...

  7. The streptococcal phage SA2 and B30 endolysins act synergistically and kill mastitis causing streptococci in milk

    Science.gov (United States)

    Bovine mastitis results in billion dollar losses annually in the United States alone. Among the most relevant causative agents of this disease are members of the genus Streptococcus, particularly the species S. agalactiae (Group B Streptococcus; GBS), S. dysgalactiae (Group C; GCS), and S. uberis....

  8. Increased Age, but Not Parity Predisposes to Higher Bacteriuria Burdens Due to Streptococcus Urinary Tract Infection and Influences Bladder Cytokine Responses, Which Develop Independent of Tissue Bacterial Loads.

    Science.gov (United States)

    Sullivan, Matthew J; Carey, Alison J; Leclercq, Sophie Y; Tan, Chee K; Ulett, Glen C

    2016-01-01

    Streptococcus agalactiae causes urinary tract infection (UTI) in pregnant adults, non-pregnant adults, immune-compromised individuals and the elderly. The pathogenesis of S. agalactiae UTI in distinct patient populations is poorly understood. In this study, we used murine models of UTI incorporating young mice, aged and dam mice to show that uropathogenic S. agalactiae causes bacteriuria at significantly higher levels in aged mice compared to young mice and this occurs coincident with equivalent levels of bladder tissue colonisation at 24 h post-infection (p.i.). In addition, aged mice exhibited significantly higher bacteriuria burdens at 48 h compared to young mice, confirming a divergent pattern of bacterial colonization in the urinary tract of aged and young mice. Multiparous mice, in contrast, exhibited significantly lower urinary titres of S. agalactiae compared to age-matched nulliparous mice suggesting that parity enhances the ability of the host to control S. agalactiae bacteriuria. Additionally, we show that both age and parity alter the expression levels of several key regulatory and pro-inflammatory cytokines, which are known to be important the immune response to UTI, including Interleukin (IL)-1β, IL-12(p40), and Monocyte Chemoattractant Protein-1 (MCP-1). Finally, we demonstrate that other cytokines, including IL-17 are induced significantly in the S. agalactiae-infected bladder regardless of age and parity status. Collectively, these findings show that the host environment plays an important role in influencing the severity of S. agalactiae UTI; infection dynamics, particularly in the context of bacteriuria, depend on age and parity, which also affect the nature of innate immune responses to infection.

  9. Maternal and neonatal colonisation of group B streptococcus at Muhimbili National Hospital in Dar es Salaam, Tanzania: prevalence, risk factors and antimicrobial resistance

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    Lyamuya Eligius F

    2009-12-01

    Full Text Available Abstract Background Group B streptococcus (GBS, which asymptomatically colonises the vaginal and rectal areas of women, is the leading cause of septicemia, meningitis and pneumonia in neonates. In Tanzania no studies have been done on GBS colonisation of pregnant women and neonates. This study was conducted in Dar es Salaam, Tanzania to determine the prevalence of GBS colonisation among pregnant women, the neonatal colonisation rate and the antimicrobial susceptibility, thus providing essential information to formulate a policy for treatment and prevention regarding perinatal GBS diseases. Methods This cross sectional study involved 300 pregnant women attending antenatal clinic and their newborns delivered at Muhimbili National Hospital (MNH between October 2008 and March 2009. High vaginal, rectal, nasal, ear and umbilical swabs were cultured on Todd Hewitt Broth and in 5% sheep blood agar followed by identification of isolates using conventional methods and testing for their susceptibility to antimicrobial agents using the Kirby-Bauer method. Results GBS colonisation was confirmed in 23% of pregnant women and 8.9% of neonates. A higher proportion of GBS were isolated from the vagina (12.3% as compared to the rectum (5%. Prolonged duration of labour (>12 hrs was significantly shown to influence GBS colonisation in neonates P Conclusion Our findings seem to suggest that a quarter of pregnant women attending ANC clinic at MNH and approximately 10% of their newborns are colonised with GBS. All isolates were found to be sensitive to vancomycin and ampicillin which seem to be the most effective antibiotics for the time being. However there is a need for continuous antibiotics surveillance of GBS to monitor trend of resistance. The high isolation frequency of GBS among pregnant women suggests routine antenatal screening at 35 to 37 weeks of gestation in order to provide antibiotic prophylaxis to GBS carrier.

  10. Epidemiology of Toxoplasma and CMV serology and of GBS colonization in pregnancy and neonatal outcome in a Sicilian population.

    Science.gov (United States)

    Puccio, Giuseppe; Cajozzo, Cinzia; Canduscio, Laura Antonella; Cino, Lucia; Romano, Amelia; Schimmenti, Maria Gabriella; Giuffrè, Mario; Corsello, Giovanni

    2014-02-22

    Aim of our study is to analyze the immunological status in pregnancy for two main TORCH agents, Toxoplasma and Cytomegalovirus (CMV), and the results of group B streptococcus (GBS) screening, assessing the risk for congenital infection in a population from Palermo, Italy. We retrospectively analyzed the medical records of all inborn live newborns who were born in our division during 2012, gathering information about the mother, the pregnancy and neonatal hospitalization at birth. Whenever data were available, we categorized the serologic status of the mothers for Toxoplasma and CMV. We also considered the results of rectal and vaginal swabs for GBS. We compared the results in Italian and immigrant mothers. The neonatal outcome was evaluated in all cases at risk. Prevalence of anti-Toxo IgG antibodies was 17.97%, and was significantly higher in immigrant women (30% vs 16.4% in Italian women; p = 0.0008). Prevalence of anti-CMV IgG antibodies was 65.87%. Again, it was significantly higher in immigrant women (91.4% vs 62.5%, p = 3.31e-08). We compared those data with a previous study performed in our hospital in 2005-2006, and found that the prevalence of anti-Toxoplasma and anti-CMV antibodies in our population has remained stable, both in the immigrant and in the local population. Seroconversion rates and neonatal infections were rare: no seroconversions were observed for Toxoplasma, 4 seroconversions for CMV. One neonatal Toxoplasma infection and two neonatal CMV infections were documented. In some cases with dubious patterns or probable persistence of IgM, we performed additional tests and follow-up. Vaginal and rectal swabs were positive for GBS in 7.98% of cases, with no significant difference between the Italian and the immigrant population. No GBS neonatal sepsis was documented. The prevalence of Toxoplasma IgG antibodies in pregnant women was low in our population, if compared with European countries and with other parts of Italy, and is significantly

  11. Activity of Genital Tract Secretions and Synthetic Antimicrobial Peptides against Group B Streptococcus.

    Science.gov (United States)

    Agarwal, Nidhi; Buckley, Niall; Nakra, Natasha; Gialanella, Philip; Yuan, Weirong; Ghartey, Jeny P

    2015-12-01

    Genital tract secretions inhibit Escherichia coli (E. coli) through antimicrobial peptides (AMP) secreted by the host and vaginal microbiota. However, there are limited data against group B Streptococcus (GBS). Group B Streptococcus were incubated with cervico-vaginal lavage (CVL) samples from healthy non-pregnant women (n = 12) or synthetic AMP and monitored for bacterial growth using a turbidimetric approach. E. coli inhibitory activity was determined by a colony-forming unit assay. None of the CVL samples inhibited GBS. The human neutrophil peptide-1 and human defensin 5 inhibited GBS growth by ≥80% at concentrations ≥20 μg/mL and ≥50 μg/mL, respectively, while human beta-defensin 2 and LL-37 did not inhibit at highest concentration tested (100 μg/mL). In contrast, all AMP inhibited E. coli. Antimicrobial peptides may protect against E. coli colonization but have more limited activity against GBS. Future studies will focus on augmenting host defense with specific AMP to prevent genitourinary infection with these pathogenic organisms. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Infection and cellular defense dynamics in a novel 17β-estradiol murine model of chronic human group B streptococcus genital tract colonization reveal a role for hemolysin in persistence and neutrophil accumulation.

    Science.gov (United States)

    Carey, Alison J; Tan, Chee Keong; Mirza, Shaper; Irving-Rodgers, Helen; Webb, Richard I; Lam, Alfred; Ulett, Glen C

    2014-02-15

    Genital tract carriage of group B streptococcus (GBS) is prevalent among adult women; however, the dynamics of chronic GBS genital tract carriage, including how GBS persists in this immunologically active host niche long term, are not well defined. To our knowledge, in this study, we report the first animal model of chronic GBS genital tract colonization using female mice synchronized into estrus by delivery of 17β-estradiol prior to intravaginal challenge with wild-type GBS 874391. Cervicovaginal swabs, which were used to measure bacterial persistence, showed that GBS colonized the vaginal mucosa of mice at high numbers (10(6)-10(7) CFU/swab) for at least 90 d. Cellular and histological analyses showed that chronic GBS colonization of the murine genital tract caused significant lymphocyte and PMN cell infiltrates, which were localized to the vaginal mucosal surface. Long-term colonization was independent of regular hormone cycling. Immunological analyses of 23 soluble proteins related to chemotaxis and inflammation showed that the host response to GBS in the genital tract comprised markers of innate immune activation including cytokines such as GM-CSF and TNF-α. A nonhemolytic isogenic mutant of GBS 874391, Δcyle9, was impaired for colonization and was associated with amplified local PMN responses. Induction of DNA neutrophil extracellular traps, which was observed in GBS-infected human PMNs in vitro in a hemolysin-dependent manner, appeared to be part of this response. Overall, this study defines key infection dynamics in a novel murine model of chronic GBS genital tract colonization and establishes previously unknown cellular and soluble defense responses to GBS in the female genital tract.

  13. Using selective chromogenic plates to optimize isolation of group B Streptococcus in pregnant women

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    Romano Mattei

    2014-03-01

    Full Text Available Group B Streptococcus (GBS remains the leading cause of severe bacterial infections (sepsis, meningitis, pneumonia in neonates. We compared the detection of GBS from recto-vaginal swabs on blood agar and two chromogenic media and evaluated their antibiotic susceptibility. A total of 1351 swabs were taken from pregnant women at 35-37 weeks of gestation. Following enrichment in Todd Hewitt broth + nalidixic acid and colistin, the samples were plated on Columbia CNA agar (CNA, chromID Strepto B agar (STRB and Granada Agar (GRAN, respectively. GBS were found in 22.4% of recto-vaginal swabs from pregnant women. Sensitivity, specificity, positive and negative predictive values of GBS detection were 88%, 88%, 81% and 96% for CNA, 99%, 97%, 90% and 99% for STRB and 94%, 99%, 98% e 99% for GRAN; Cohen’s k index concordances for CNA, STREB and GRAN were 0.68, 0.92 and 0.96, respectively. All isolates were susceptible to penicillin, whereas resistances of erythromycin and clindamycin were 40% and 42%, respectively. To conclude, selective broth enrichment combined with chromogenic plates is recommended for GBS screening in pregnant women.

  14. Structure of a conjugative element in Streptococcus pneumoniae

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, M.N.; Priebe, S.D.; Guild, W.R.

    1986-06-01

    The authors have cloned and mapped a 69-kilobase (kb) region of the chromosome of Streptococcus pneumoniae DP1322, which carries the conjugative Omega(cat-tet) insertion from S. pneumoniae BM6001. This element proved to be 65.5 kb in size. Location of the junctions was facilitated by cloning a preferred target region from the wild-type strain Rx1 recipient genome. This target site was preferred by both the BM6001 element and the cat-erm-tet element from Streptococcus agalactiae B109. Within the BM6001 element cat and tet were separated by 30 kb, and cat was flanked by two copies of a sequence that was also present in the recipient strain Rx1 DNA. Another sequence at least 2.4 kb in size was found inside the BM6001 element and at two places in the Rx1 genome. Its role is unknown. The ends of the BM6001 element appear to be the same as those of the B109 element, both as seen after transfer to S. pneumoniae and as mapped by others in pDP5 after transposition in Streptococcus faecalis. No homology is seen between the ends of the BM6001 element and no evidence found suggesting that it ever circularizes.

  15. Evaluation of chromogenic medium and direct latex agglutination test for detection of group B streptococcus in vaginal specimens from pregnant women in Lebanon and Kuwait.

    Science.gov (United States)

    Ghaddar, Nahed; Alfouzan, Wadha; Anastasiadis, Elie; Al Jiser, Tamima; Itani, Saad Eddine; Dernaika, Racha; Eid, Toufic; Ghaddar, Ali; Charafeddine, Adib; Dhar, Rita; El Hajj, Hiba

    2014-10-01

    This study was undertaken to evaluate chromogenic medium and a direct latex agglutination test (DLA) for detection of Group B Streptococcus (GBS) in the vaginal specimens of pregnant women, and to ascertain the prevalence of GBS in this population in Kuwait and Lebanon. Vaginal swabs, collected from women at 35-37 weeks of gestation, were cultured on 5 % sheep blood agar (SBA), colistin nalidixic acid agar (CNA), Strept B Select chromogenic agar (SBS) as well as Lim enrichment broth in 168 cases in Lebanon while only SBA was used for 1391 samples in Kuwait. In addition, vaginal samples from 102 GBS-positive and 20 GBS-negative women near the time of delivery were collected in Kuwait for evaluation of the DLA test. During the study period, the prevalence of GBS colonization was determined to be 20.7 % (288/1391) in Kuwait while 18.4 % (31) of 168 pregnant women in Lebanon had vaginal cultures positive for GBS. By direct plating of vaginal swabs on the three media used, the isolation rates of GBS were 51.6, 64.5 and 77.4 % on SBA, CNA and SBS, respectively, which increased to 90.35, 93.1 and 96.8 %, respectively, following subculture in Lim broth after 18 h of incubation. The sensitivity of the DLA test was found to be dependent on the density of GBS colonization, resulting in 100 % sensitivity and 100 % specificity for heavy (>10(2) c.f.u. per swab) and moderately heavy (50-100 c.f.u. per swab) growth of GBS. However, for vaginal specimens yielding women. The DLA test, in particular, could prove to be a useful tool for immediate detection of GBS in women near delivery so that intrapartum antibiotic prophylaxis can be initiated. © 2014 The Authors.

  16. Implication of TLR- but not of NOD2-signaling pathways in dendritic cell activation by group B Streptococcus serotypes III and V.

    Directory of Open Access Journals (Sweden)

    Paul Lemire

    Full Text Available Group B Streptococcus (GBS is an important agent of life-threatening invasive infection. It has been previously shown that encapsulated type III GBS is easily internalized by dendritic cells (DCs, and that this internalization had an impact on cytokine production. The receptors underlying these processes are poorly characterized. Knowledge on the mechanisms used by type V GBS to activate DCs is minimal. In this work, we investigated the role of Toll-like receptor (TLR/MyD88 signaling pathway, the particular involvement of TLR2, and that of the intracellular sensing receptor NOD2 in the activation of DCs by types III and V GBS. The role of capsular polysaccharide (CPS, one of the most important GBS virulence factors in bacterial-DC interactions was evaluated using non-encapsulated mutants. Despite differences in the role of CPS between types III and V GBS in bacterial internalization and intracellular survival, no major differences were observed in their capacity to modulate release of cytokines by DC. For both serotypes, CPS had a minor role in this response. Production of cytokines by DCs was shown to strongly rely on MyD88-dependent signaling pathways, suggesting that DCs recognize GBS and become activated mostly through TLR signaling. Yet, GBS-infected TLR2-/- DCs only showed a partial reduction in the production of IL-6 and CXCL1 compared to control DCs. Surprisingly, CXCL10 release by type III or type V GBS-infected DCs was MyD88-independent. No differences in DC activation were observed between NOD2-/- and control DCs. These results demonstrate the involvement of various receptors and the complexity of the cytokine production pathways activated by GBS upon DC infection.

  17. Mycoplasma agalactiae Induces Cytopathic Effects in Infected Cells Cultured In Vitro.

    Directory of Open Access Journals (Sweden)

    Shrilakshmi Hegde

    Full Text Available Mycoplasma agalactiae is the etiological agent of the contagious agalactia syndrome in sheep and goats and causes significant economic losses worldwide. Yet the mechanism of pathogenesis is largely unknown. Even whole-genome sequence analysis of its pathogenic type strain did not lead to any conclusions regarding its virulence or pathogenicity factors. Although inflammation and tissue destruction at the local site of M. agalactiae infection are largely considered as effects of the host immune response, the direct effect of the agent on host cells is not completely understood. The aim of this study was to investigate the effect of M. agalactiae infection on the quality and viability of host cells in vitro. Changes in cell morphology including cell elongation, cytoplasm shrinkage and membrane blebbing were observed in infected HeLa cells. Chromatin condensation and increased caspase-3 cleavage in infected HeLa cells 48 h after infection suggests an apoptosis-like phenomenon in M. agalactiae-infected cells. In compliance with these results, decreased viability and cell lysis of M. agalactiae-infected HeLa cells was also observed. Measurement of the amount of LDH released after M. agalactiae infection revealed a time- and dose-dependent increase in HeLa cell lysis. A significant decrease in LDH released after gentamicin treatment of infected cells confirmed the major role of cytadherent M. agalactiae in inducing host cell lysis. This is the first study illustrating M. agalactiae's induction of cytopathic effects in infected HeLa cells. Further detailed investigation of infected host tissue for apoptotic markers might demonstrate the association between M. agalactiae-induced host cell lysis and the tissue destruction observed during M. agalactiae natural infection.

  18. Coherent 40 Gb/s SP-16QAM and 80 Gb/s PDM-16QAM in an Optimal Supercomputer Optical Switch Fabric

    DEFF Research Database (Denmark)

    Karinou, Fotini; Borkowski, Robert; Zibar, Darko

    2013-01-01

    We demonstrate, for the first time, the feasibility of using 40 Gb/s SP-16QAM and 80 Gb/s PDM-16QAM in an optimized cell switching supercomputer optical interconnect architecture based on semiconductor optical amplifiers as ON/OFF gates.......We demonstrate, for the first time, the feasibility of using 40 Gb/s SP-16QAM and 80 Gb/s PDM-16QAM in an optimized cell switching supercomputer optical interconnect architecture based on semiconductor optical amplifiers as ON/OFF gates....

  19. Genome analysis of multiple pathogenic isolates of Streptococcus agalactiae : Implications for the microbial "pan-genome"

    NARCIS (Netherlands)

    Tettelin, H; Masignani, [No Value; Cieslewicz, MJ; Donati, C; Medini, D; Ward, NL; Angiuoli, SV; Crabtree, J; Jones, AL; Durkin, AS; DeBoy, RT; Davidsen, TM; Mora, M; Scarselli, M; Ros, IMY; Peterson, JD; Hauser, CR; Sundaram, JP; Nelson, WC; Madupu, R; Brinkac, LM; Dodson, RJ; Rosovitz, MJ; Sullivan, SA; Daugherty, SC; Haft, DH; Selengut, J; Gwinn, ML; Zhou, LW; Zafar, N; Khouri, H; Radune, D; Dimitrov, G; Watkins, K; O'Connor, KJB; Smith, S; Utterback, TR; White, O; Rubens, CE; Grandi, G; Madoff, LC; Kasper, DL; Telford, JL; Wessels, MR; Rappuoli, R; Fraser, CM

    2005-01-01

    The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design. Unfortunately, the sequence of a single genome does not reflect how genetic variability drives pathogenesis within a bacterial species and

  20. [Clinical analysis and follow-up of neonatal purulent meningitis caused by group B streptococcus].

    Science.gov (United States)

    Zhu, Minli; Zhu, Jianghu; Li, Haijing; Liu, Peining; Lin, Zhenlang

    2014-02-01

    To study the clinical characteristics, antibiotics sensitivity and outcome of group B streptococcus (GBS) meningitis in neonates in order to provide the guide for early diagnosis and appropriate treatment. A retrospective review was performed and a total of 13 cases of neonatal purulent meningitis caused by GBS were identified in the Neonatal Intensive Care Unit of Yuying Children's Hospital of Wenzhou Medical University from January 1, 2005 to May 31, 2013. The clinical characteristics, antibiotics sensitivity test results and outcome were analyzed. Fever, poor feeding, seizure and lethargy were common clinical signs of neonatal purulent meningitis caused by GBS. Three cases of early onset GBS meningitis received prepartum antibiotics. All 13 cases had abnormal C-reactive protein (CRP) level, and 11 cases had increased CRP within hours after admission. Of the 13 patients, 7 were cured, 4 discharged with improvement, 2 patients died during hospitalization after being given up because of serious complication. The average length of stay for recovered patients was (47 ± 21)d. Acute complications mainly included hyponatremia (5 cases), intracranial hemorrhage (3 cases) , ventriculomegaly (3 cases) , subdural collection (2 cases) , hydrocephalus (2 cases), septic shock (2 cases), cerebral hernia (1 case), encephalomalacia (1 case). One preterm patient with early onset GBS meningitis died 1 month after hospital discharge. Among 7 survivors with 10-24 months follow-up, 3 were early onset GBS meningitis, 2 with normal results of neurologic examination, 1 with delayed motor development, 4 were late onset GBS meningitis, 1 with normal results of neurologic examination, 3 were neurologically impaired with manifestations including delayed motor development (2 cases) and seizures (1 case). All the GBS strains were sensitive to penicillin and linezolid (13/13, 10/10), the susceptibility to levofloxacin, ampicillin and vancomycin were 11/12, 9/10, 8/13 respectively. The clinical

  1. A new orthogonal labeling scheme based on a 40-Gb/s DPSK payload and a 2.5-Gb/s PolSK label

    DEFF Research Database (Denmark)

    Xu, Lin; Chi, Nan; Oxenløwe, Leif Katsuo

    2005-01-01

    In this letter, we propose and experimentally demonstrate a new orthogonal labeling scheme based on a 40-Gb/s differential phase-shift keying payload and a 2.5-Gb/s polarization-shift keying label, which entirely eliminates the modulation crosstalk between the payload and label and shows negligible...

  2. Carrier phase estimation for coherent equalization of 43-Gb/s POLMUX-NRZ-DQPSK transmission with 10.7-Gb/s NRZ neighbours

    NARCIS (Netherlands)

    Borne, van den D.; Fludger, C.R.S.; Duthel, T.; Wuth, T.; Schmidt, E.D.; Schulien, C.; Gottwald, E.; Khoe, G.D.; Waardt, de H.

    2007-01-01

    We show the influence of 10.7-Gb/s NRZ neighbors on 43-Gb/s polarization-multiplexed NRZ-DQPSK transmission combined with digital coherent equalization. The impact of XPM induced phase noise is reduced with an optimized carrier phase estimation (CPE) algorithm.

  3. Phenotypical characteristics of group B streptococcus in parturients

    Directory of Open Access Journals (Sweden)

    Jose Antonio Simoes

    Full Text Available Colonization by Group B Streptococcus (GBS is highly prevalent among pregnant women, with prevalence rates ranging between 4% and 30%. The infection may be transmitted vertically and may result in serious neonatal consequences. In the period from November 2003 to May 2004, a cross-sectional study was carried out among 316 parturients at the Jundiaí Teaching Hospital to establish the prevalence of genital GBS colonization, to identify the factors associated with colonization and the characteristic phenotypes of these streptococci. Samples from rectal and vaginal areas were collected for selective culture in Todd-Hewitt broth. Susceptibility to 7 antimicrobial agents was tested using the antibiotic diffusion disk technique, and the isolated strains were classified using specific antisera. The prevalence of GBS colonization was 14.6%. No strain was resistant to penicillin, ampicillin, erythromycin or nitrofurantoin. The majority of strains were sensitive to cephalothin. Greatest resistance was to gentamicin (76.1%, followed by clindamycin (17.4%. The most frequent serotype was Ib (23.9%, followed by serotypes II and Ia (19.6% and 17.4%, respectively. There was no correlation between serotype and greater antimicrobial resistance. In conclusion, the prevalence of GBS in parturients was high and penicillin continues to be the drug of choice for intrapartum prophylaxis. The most frequent serotype (Ib found in this study differs from those found in the majority of studies carried out in other countries, revealing the need to identify prevalent serotypes in each region so that specific vaccines can be designed.

  4. Intrapartum antibiotic exposure for group B Streptococcus treatment did not increase penicillin allergy in children.

    Science.gov (United States)

    May, Sara M; Hartz, Martha F; Joshi, Avni Y; Park, Miguel A

    2016-02-01

    Group B Streptococcus (GBS) is the leading infectious cause of neonatal morbidity and mortality in the United States. Intrapartum administration of antibiotics to mothers with positivity to GBS is performed for prevention, with penicillin being the drug of choice. Previous studies have noted an increase in atopic diseases other than drug allergy associated with intrapartum antibiotic exposure. To determine whether intrapartum exposure to penicillin for GBS increases the likelihood of penicillin allergy in children. Retrospective chart review was performed for patients from a birth cohort. The birth cohort included children born in 2007 at a tertiary care hospital and had local addresses. Information on GBS status of the mother, intrapartum antibiotic exposure, delivery mode, and birth order was collected and analyzed. Of 927 children identified, 804 were included in the cohort. Eighty children (10%) had a reported penicillin allergy; most were white (79%) and boys (61%). Intrapartum exposure to penicillin (odds ratio 0.84, 95% confidence interval 0.45-1.57, P = .59) or to amoxicillin or ampicillin (odds ratio 0.22, 95% confidence interval 0.01-3.71, P = .29) did not increase the risk of penicillin allergy in children. In addition, all other factors evaluated did not affect the risk of penicillin allergy in children. To the authors' knowledge, this is the first study to evaluate intrapartum exposure to penicillin for GBS treatment and subsequent development of penicillin allergy in the child. In contrast to other atopic diseases, intrapartum antibiotic exposure does not alter the risk of penicillin allergy. Parents and obstetricians should be reassured when using penicillin for prevention of neonatal GBS. Published by Elsevier Inc.

  5. Prevalence of streptococcus group B in tracheal tube secretions of neonates with respiratory distress: a brief report

    Directory of Open Access Journals (Sweden)

    Khosravi N

    2013-02-01

    Full Text Available Background: Infection with group B streptococcus (GBS can present with respiratory distress, Pneumonia, meningitis and Osteomyelitis in neonates. The aim of this study was to determine the prevalence of GBS colonization in trachea of intubated neonates.Methods: This observational analytic study was performed upon 33 intubated neonates due to respiratory distress in neonatal intensive care unit (NICU Rasoul Hospital in Tehran, Iran during 2010-2012. Tracheal secretions cultured upon TODD-HEWITT BROTH and sheep blood agar 5%., chi-square test was used for compare the qualitative variables. P<0.05 was considered meaningful.Results: Three cases had positive streptococcal culture (9.1% and four cases had posi-tive culture for non-streptococcal organisms. no meaningful relation observed between positive GBS culture and neonatal gender, kind of delivery, PROM.Conclusion: Prevalence of GBS positive results (9% in present study is very close to GBS colonization in pregnant women; although the higher colonization rate of pregnant women are expected.

  6. Prenatal and neonatal Group B Streptococcus screening and serotyping in Lebanon: incidence and implications.

    Science.gov (United States)

    Seoud, Muheiddine; Nassar, Anwar H; Zalloua, Pierre; Boghossian, Nansi; Ezeddine, Jihad; Fakhoury, Hassan; Abboud, Joseph; Melki, Imad; Araj, George; Nacouzi, Ghinwa; Sanyoura, May; Yunis, Khalid

    2010-03-01

    The study aimed at determining the prevalence, risk factors, perinatal transmission, and serotypes of Group B Streptococcus (GBS) among pregnant women and their newborns in Beirut, Lebanon. This was a cross-sectional study of all pregnant women admitted from February to September 2006 to three major hospitals. Overall, 137 of 775 (17.7%) mothers and 50 of 682 newborns (7.3%) tested positive for GBS. Maternal colonization was not associated with maternal age, household income, gravidity, intrapartum fever, preterm labor, or premature rupture of membrane. Transmission rate was 40/120 (30%). Serotype 5 (24.1%) was the most common followed by serotype 1a (15.0%), 3 (14.4%), 2 (11.8%) and 1b (7.5%). Pregnant women in Lebanon appear to have a relatively high prevalence of GBS colonization with no identifiable risk factors for its acquisition. These results could provide basis for the institution of a national policy for universal maternal GBS screening to reduce neonatal morbidity and mortality.

  7. Evaluation of a rapid, real-time intrapartum group B Streptococcus assay

    Science.gov (United States)

    YOUNG, Brett C.; DODGE, Laura E.; GUPTA, Munish; RHEE, Julie S.; HACKER, Michele R.

    2011-01-01

    OBJECTIVE To evaluate an intrapartum nucleic acid amplification test (NAAT) for Group B streptococcus (GBS). STUDY DESIGN Prospective cohort study of 559 women comparing intrapartum GBS culture with antepartum culture and intrapartum NAAT. RESULTS GBS prevalence was 19.5% by antepartum culture and 23.8% by intrapartum culture. Compared with intrapartum culture, antepartum culture had 69.2% sensitivity (60.6–76.9) and 96.0% specificity (93.7–97.7). The NAAT demonstrated sensitivity of 90.8% (84.6–95.2), specificity of 97.6% (95.6–98.8), and predictive values exceeding 92%. The incidence of discordant cultures was 10.4%. Of the women with negative antepartum and positive intrapartum cultures, only 1 (2.4%) received intrapartum antibiotics. Compared with white women, black (P=0.02) and Hispanic (P=0.02) women were more likely to have discordant cultures. CONCLUSION This intrapartum NAAT has excellent characteristics. It may be superior to antepartum culture for detecting intrapartum GBS—allowing more accurate management of laboring mothers and reducing neonatal GBS sepsis. PMID:21864820

  8. Membrane Vesicles of Group B Streptococcus Disrupt Feto-Maternal Barrier Leading to Preterm Birth.

    Directory of Open Access Journals (Sweden)

    Manalee Vishnu Surve

    2016-09-01

    Full Text Available Infection of the genitourinary tract with Group B Streptococcus (GBS, an opportunistic gram positive pathogen, is associated with premature rupture of amniotic membrane and preterm birth. In this work, we demonstrate that GBS produces membrane vesicles (MVs in a serotype independent manner. These MVs are loaded with virulence factors including extracellular matrix degrading proteases and pore forming toxins. Mice chorio-decidual membranes challenged with MVs ex vivo resulted in extensive collagen degradation leading to loss of stiffness and mechanical weakening. MVs when instilled vaginally are capable of anterograde transport in mouse reproductive tract. Intra-amniotic injections of GBS MVs in mice led to upregulation of pro-inflammatory cytokines and inflammation mimicking features of chorio-amnionitis; it also led to apoptosis in the chorio-decidual tissue. Instillation of MVs in the amniotic sac also resulted in intrauterine fetal death and preterm delivery. Our findings suggest that GBS MVs can independently orchestrate events at the feto-maternal interface causing chorio-amnionitis and membrane damage leading to preterm birth or fetal death.

  9. Membrane Vesicles of Group B Streptococcus Disrupt Feto-Maternal Barrier Leading to Preterm Birth

    Science.gov (United States)

    Sthanam, Lakshmi Kavitha; Srivastava, Rohit; Basu, Bhakti; Dutta, Suryendu; Sen, Shamik; Modi, Deepak

    2016-01-01

    Infection of the genitourinary tract with Group B Streptococcus (GBS), an opportunistic gram positive pathogen, is associated with premature rupture of amniotic membrane and preterm birth. In this work, we demonstrate that GBS produces membrane vesicles (MVs) in a serotype independent manner. These MVs are loaded with virulence factors including extracellular matrix degrading proteases and pore forming toxins. Mice chorio-decidual membranes challenged with MVs ex vivo resulted in extensive collagen degradation leading to loss of stiffness and mechanical weakening. MVs when instilled vaginally are capable of anterograde transport in mouse reproductive tract. Intra-amniotic injections of GBS MVs in mice led to upregulation of pro-inflammatory cytokines and inflammation mimicking features of chorio-amnionitis; it also led to apoptosis in the chorio-decidual tissue. Instillation of MVs in the amniotic sac also resulted in intrauterine fetal death and preterm delivery. Our findings suggest that GBS MVs can independently orchestrate events at the feto-maternal interface causing chorio-amnionitis and membrane damage leading to preterm birth or fetal death. PMID:27583406

  10. Group B streptococcus serotype prevalence in reproductive-age women at a tertiary care military medical center relative to global serotype distribution

    Directory of Open Access Journals (Sweden)

    Williams Julie

    2010-11-01

    Full Text Available Abstract Background Group B Streptococcus (GBS serotype (Ia, Ib, II-IX correlates with pathogen virulence and clinical prognosis. Epidemiological studies of seroprevalence are an important metric for determining the proportion of serotypes in a given population. The purpose of this study was to evaluate the prevalence of individual GBS serotypes at Madigan Healthcare System (Madigan, the largest military tertiary healthcare facility in the Pacific Northwestern United States, and to compare seroprevalences with international locations. Methods To determine serotype distribution at Madigan, we obtained GBS isolates from standard-of-care anogenital swabs from 207 women of indeterminate gravidity between ages 18-40 during a five month interval. Serotype was determined using a recently described molecular method of polymerase chain reaction by capsular polysaccharide synthesis (cps genes associated with pathogen virulence. Results Serotypes Ia, III, and V were the most prevalent (28%, 27%, and 17%, respectively. A systematic review of global GBS seroprevalence, meta-analysis, and statistical comparison revealed strikingly similar serodistibution at Madigan relative to civilian-sector populations in Canada and the United States. Serotype Ia was the only serotype consistently higher in North American populations relative to other geographic regions (p Conclusion This study establishes PCR-based serotyping as a viable strategy for GBS epidemiological surveillance. Our results suggest that GBS seroprevalence remains stable in North America over the past two decades.

  11. The GBS code for tokamak scrape-off layer simulations

    International Nuclear Information System (INIS)

    Halpern, F.D.; Ricci, P.; Jolliet, S.; Loizu, J.; Morales, J.; Mosetto, A.; Musil, F.; Riva, F.; Tran, T.M.; Wersal, C.

    2016-01-01

    We describe a new version of GBS, a 3D global, flux-driven plasma turbulence code to simulate the turbulent dynamics in the tokamak scrape-off layer (SOL), superseding the code presented by Ricci et al. (2012) [14]. The present work is driven by the objective of studying SOL turbulent dynamics in medium size tokamaks and beyond with a high-fidelity physics model. We emphasize an intertwining framework of improved physics models and the computational improvements that allow them. The model extensions include neutral atom physics, finite ion temperature, the addition of a closed field line region, and a non-Boussinesq treatment of the polarization drift. GBS has been completely refactored with the introduction of a 3-D Cartesian communicator and a scalable parallel multigrid solver. We report dramatically enhanced parallel scalability, with the possibility of treating electromagnetic fluctuations very efficiently. The method of manufactured solutions as a verification process has been carried out for this new code version, demonstrating the correct implementation of the physical model.

  12. Streptococcus suis, an emerging drug-resistant animal and human pathogen

    Directory of Open Access Journals (Sweden)

    Claudio ePalmieri

    2011-11-01

    Full Text Available Streptococcus suis, a major porcine pathogen, has been receiving growing attention not only for its role in severe and increasingly reported infections in humans, but also for its involvement in drug resistance. Recent studies and the analysis of sequenced genomes have been providing important insights into the S. suis resistome, and have resulted in the identification of resistance determinants for tetracyclines, macrolides, aminoglycosides, chloramphenicol, antifolate drugs, streptothricin, and cadmium salts. Resistance gene-carrying genetic elements described so far include integrative and conjugative elements, transposons, genomic islands, phages, and chimeric elements. Some of these elements are similar to those reported in major streptococcal pathogens such as Streptococcus pyogenes, Streptococcus pneumoniae, and Streptococcus agalactiae and share the same chromosomal insertion sites. The available information strongly suggests that S. suis is an important antibiotic resistance reservoir that can contribute to the spread of resistance genes to the above-mentioned streptococci. S. suis is thus a paradigmatic example of possible intersections between animal and human resistomes.

  13. Emergence of group B Streptococcus serotype IV in women of child-bearing age in Ireland.

    LENUS (Irish Health Repository)

    Kiely, R A

    2011-02-01

    This study determined the carriage rate and serotype distribution of group B Streptococcus (GBS) in women of child-bearing age in the southern region of Ireland. A total of 2000 vaginal swabs collected in two periods in 2004 and 2006 were examined and revealed a GBS carriage rate of 16·1%. Serotyping of isolates showed that serotypes Ia, II, III, IV, and V were the most prevalent. A high prevalence of serotype IV was found, increasing from 7·6% to 15·2% between 2004 and 2006. Random amplified polymorphic DNA analysis demonstrated considerable genetic heterogeneity in the serotype IV isolates. This serotype should be considered for inclusion in potential vaccines for use in Ireland.

  14. Transcriptomic response of goat mammary epithelial cells to Mycoplasma agalactiae challenge – a preliminary study

    DEFF Research Database (Denmark)

    Ogorevc, Jernej; Mihevc, Sonja Prpar; Hedegaard, Jakob

    2015-01-01

    Mycoplasma agalactiae (Ma) is one of the main aetiological agents of intramammary infections in small ruminants, causing contagious agalactia. To better understand the underlying disease patterns a primary goat mammary epithelial cell (pgMEC) culture was established from the mammary tissue and ch....... Additionally, the results represent comprehensive goat mammary transcriptome information and demonstrate the applicability of the comparative genomics approach for annotation of goat data, using transcriptome information of a closely related species (Bos taurus) as a reference....

  15. Transcriptomic response of goat mammary epithelial cells to Mycoplasma agalactiae challenge – a preliminary study

    DEFF Research Database (Denmark)

    Ogorevc, Jernej; Mihevc, Sonja Prpar; Hedegaard, Jakob

    2015-01-01

    Mycoplasma agalactiae (Ma) is one of the main aetiological agents of intramammary infections in small ruminants, causing contagious agalactia. To better understand the underlying disease patterns a primary goat mammary epithelial cell (pgMEC) culture was established from the mammary tissue......, steroid metabolism, fatty acid metabolism, apoptosis signalling, transcription regulation, and cell cycle regulation. Based on the results we suggest that mammary epithelial cells in vivo contribute to the immune system by the induced expression of cytokines and other chemotactic agents, activation...

  16. Isolation and prevalence of Mycoplasma agalactiae in Kurdish sheep in Kurdistan, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Khezri

    Full Text Available Aim: Ruminant Mycoplasmosis are important diseases worldwide and several are listed by the World Organization for Animal Health (OIE to be of major economic significant. The aim of this study was to isolation mycoplasmas from sheep presenting contagious agalactiae (CA in Kurdistan in the West of Iran. Materials and Methods: Sixty-nine samples included (milk, conjuctiva swabs, synovial fluid and ear canal swabs were examined by PCR assay during 2011-2012. DNA was extracted from enriched samples. Two primers (forward and reverse amplify a 163bp region of 16S rRNA gene of Mycoplasma genus and two primers amplify 375bp region of 16S rRNA gene of Mycoplasma agalactiae (M. agalactiae species were used. Results: This proved that 46 samples (66.7% were infected with Mycoplasma in culture and PCR test, respectively. On the PCR test, 15 isolates (32.6% examined were positive for M. agalactiae that showed specific amplicon at 375bp. All Mycoplasma positive samples were analyzed for M. agalactiae infection by PCR method and 31 isolates (67.4% examined were negative for M. agalactiae. The finding of other mycoplasmas with significant epidemiology challenges existing plans for the control of CA in sheep population in Iran. Conclusion: The results of the present study show that M. agalactiae in CA disease in Kurdistan Province, 32.6% involved. In Iran, only M. agalactiae vaccines are commercially available, thus, the animals are not protected against these other species. [Vet World 2012; 5(12.000: 727-731

  17. Geographic Distribution of Maternal Group B Streptococcus Colonization and Infant Death During Birth Hospitalization: Eastern Wisconsin

    Directory of Open Access Journals (Sweden)

    Jessica J. F. Kram

    2016-04-01

    Full Text Available Purpose: Maternal group B Streptococcus (GBS can be transmitted from a colonized mother to newborn during vaginal delivery and may or may not contribute to infant death. This study aimed to explore the geographic distribution and risk factors of maternal GBS colonization and infant death during birth hospitalization. Methods: We retrospectively studied mothers with live birth(s in a large eastern Wisconsin hospital system from 2007 through 2013. Associations between maternal and neonatal variables, GBS colonization and infant death were examined using chi-squared, Mann-Whitney U and t-tests. Multivariable logistic regression models also were developed. Results: Study population (N = 99,305 had a mean age of 28.1 years and prepregnancy body mass index (BMI of 26.7 kg/m2; 64.0% were white, 59.2% married, 39.3% nulliparous and 25.7% cesarean delivery. Mean gestational age was 39.0 weeks. Rate of maternal GBS colonization (22.3% overall was greater in blacks (34.1% vs. 20.1% in whites, P < 0.0001, unmarried women (25.5% vs. 20.0% married, P < 0.0001, women with sexually transmitted or other genital infections (P < 0.0001 and residents of ZIP code group 532XX (P < 0.0001, and was associated with increasing BMI (P < 0.0001. All predictors of colonization were significant on multivariable analysis. Rate of infant death was 5.7 deaths/1,000 live births (n = 558 excluding lethal anomalies and stillbirths and was negatively associated with maternal GBS colonization (P < 0.0001. On multivariable analysis, 532XX ZIP code group, lower gestational age, preterm labor, hyaline membrane disease, normal spontaneous vaginal delivery, hydramnios, oligohydramnios and absence of maternal GBS were associated with infant death. Conclusions: Geographic characteristics were associated with infant death and maternal GBS colonization. Further research is needed to determine if increased surveillance or treatment of mothers colonized with GBS decreases the risk of infant

  18. Listeria monocytogenes infection in pregnancy and neonatal sepsis

    Directory of Open Access Journals (Sweden)

    Francesca Pascale

    2008-06-01

    Full Text Available Authors report a fatal neonatal sepsis caused by Listeria monocytogenes. While the diagnostic procedure aimed to identify the microrganism is described, it is emphasized the importance to recover Streptococcus agalactiae (GBS and L. monocytogenes by means of vaginal-rectal swab culture. The intrapartum screening for L. monocytogenes, by Polymerase Chain Reaction (PCR providing results in 75 minutes is also evaluated.

  19. Heterodyne detection of CPFSK signals with and without wavelength conversion up to 5 Gb/s

    DEFF Research Database (Denmark)

    Pedersen, Rune Johan Skullerud; Ebskamp, F.; Mikkelsen, Benny

    1993-01-01

    Detection of wavelength converted signals by a coherent continuous-phase frequency-shift-keying receiver is reported. The signals are wavelength converted over 35 nm, and record receiver sensitivities of -38.7 dBm at 4.0Gb/s and -35.6 dBm at 4.8Gb/s are obtained. Comparison between results...

  20. STIMULUS: End-System Network Interface Controller for 100 Gb/s Wide Area Networks

    Energy Technology Data Exchange (ETDEWEB)

    Zarkesh-Ha, Payman [University of New Mexico

    2014-09-12

    The main goal of this research grant is to develop a system-level solution leveraging novel technologies that enable network communications at 100 Gb/s or beyond. University of New Mexico in collaboration with Acadia Optronics LLC has been working on this project to develop the 100 Gb/s Network Interface Controller (NIC) under this Department of Energy (DOE) grant.

  1. First Experimental Demonstration of Coherent CAP for 300-Gb/s Metropolitan Optical Networks

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Iglesias Olmedo, Miguel; Zibar, Darko

    2014-01-01

    We report on high - capacity coherent links employing dual polarization 2D - CAP modulation, allowing for signal design in 8 - dimensional space. Successful demodulation of 221 Gb/s (7.5 b/s/Hz) and 336 Gb/s (7.8 b/s/Hz) after 225 km and 451 km of standard single - mode fiber (SSMF) is achieved....

  2. Short communication: In vitro antimicrobial susceptibility of Mycoplasma agalactiae strains isolated from dairy goats.

    Science.gov (United States)

    Paterna, A; Sánchez, A; Gómez-Martín, A; Corrales, J C; De la Fe, C; Contreras, A; Amores, J

    2013-01-01

    This study examined the susceptibility to several antimicrobials of 28 isolates of Mycoplasma agalactiae obtained from goats in a region (southeastern Spain) where contagious agalactia is endemic. For each isolate, the minimum inhibitory concentration (MIC) against 12 antimicrobials of the quinolone, macrolide, aminoglycoside, and tetracycline families was determined. The antimicrobials with the lowest MIC were enrofloxacin, ciprofloxacin, tylosin, and doxycycline, all with MIC90 (concentration at which growth of 90% of the isolates is inhibited) <1 µg/mL. Norfloxacin (a quinolone) showed a wide MIC range (0.1-12.8 µg/mL), suggesting a resistance mechanism toward this antimicrobial that was not elicited by enrofloxacin or ciprofloxacin (the other quinolones tested). Erythromycin showed the highest MIC90 such that its use against Mycoplasma agalactiae is not recommended. Finally, Mycoplasma agalactiae isolates obtained from goat herds with clinical symptoms of contagious agalactia featured higher MIC90 and MIC50 (concentration at which growth of 50% of the isolates is inhibited) values for many of the antimicrobials compared with isolates from asymptomatic animals. The relationship between the extensive use of antimicrobials in herds with clinical contagious agalactia and variations in MIC requires further study. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Exploring internal features of 16S rRNA gene for identification of clinically relevant species of the genus Streptococcus

    Science.gov (United States)

    2011-01-01

    Background Streptococcus is an economically important genus as a number of species belonging to this genus are human and animal pathogens. The genus has been divided into different groups based on 16S rRNA gene sequence similarity. The variability observed among the members of these groups is low and it is difficult to distinguish them. The present study was taken up to explore 16S rRNA gene sequence to develop methods that can be used for preliminary identification and can supplement the existing methods for identification of clinically-relevant isolates of the genus Streptococcus. Methods 16S rRNA gene sequences belonging to the isolates of S. dysgalactiae, S. equi, S. pyogenes, S. agalactiae, S. bovis, S. gallolyticus, S. mutans, S. sobrinus, S. mitis, S. pneumoniae, S. thermophilus and S. anginosus were analyzed with the purpose to define genetic variability within each species to generate a phylogenetic framework, to identify species-specific signatures and in-silico restriction enzyme analysis. Results The framework based analysis was used to segregate Streptococcus spp. previously identified upto genus level. This segregation was validated using species-specific signatures and in-silico restriction enzyme analysis. 43 uncharacterized Streptococcus spp. could be identified using this approach. Conclusions The markers generated exploring 16S rRNA gene sequences provided useful tool that can be further used for identification of different species of the genus Streptococcus. PMID:21702978

  4. 0.4 THz Photonic-Wireless Link With 106 Gb/s Single Channel Bitrate

    DEFF Research Database (Denmark)

    Jia, Shi; Pang, Xiaodan; Ozolins, Oskars

    2018-01-01

    To accommodate the demand of exponentially increased global wireless data traffic, the prospective data rates for wireless communication in the market place will soon reach 100 Gb/s and beyond. In the lab environment, wireless transmission throughput has been elevated to the level of over 100 Gb....../s attributed to the development of photonic-assisted millimeter wave and terahertz (THz) technologies. However, most of recent demonstrations with over 100 Gb/s data rates are based on spatial or frequency division multiplexing techniques, resulting in increased system's complexity and energy consumption. Here......, we experimentally demonstrate a single channel 0.4 THz photonic-wireless link achieving a net data rate of beyond 100 Gb/s by using a single pair of THz emitter and receiver, without employing any spatial/frequency division multiplexing techniques. The high throughput up to 106 Gb/s within a single...

  5. Demonstration of the First Real-Time End-to-End 40-Gb/s PAM-4 for Next-Generation Access Applications using 10-Gb/s Transmitter

    DEFF Research Database (Denmark)

    Wei, J. L.; Eiselt, Nicklas; Griesser, Helmut

    2016-01-01

    We demonstrate the first known experiment of a real-time end-to-end 40-Gb/s PAM-4 system for next-generation access applications using 10-Gb/s class transmitters only. Based on the measurement of a real-time 40-Gb/s PAM system, low-cost upstream and downstream link power budgets are estimated. Up...

  6. Controlled Human Infection for Vaccination Against Streptococcus Pyogenes

    Science.gov (United States)

    2018-04-26

    Streptococcus Pyogenes Pharyngitis; Streptococcus Pharyngitis; Strep Throat; Streptococcus Pyogenes Infection; Group A Streptococcus: B Hemolytic Pharyngitis; Group A Streptococcal Infection; Gram-Positive Bacterial Infections; Bacterial Infections

  7. Antibiotic susceptibility patterns and prevalence of group B Streptococcus isolated from pregnant women in Misiones, Argentina Sensibilidade a antibióticos e prevalência de Streptococcus do grupo B em mulheres grávidas em Missiones, Argentina

    Directory of Open Access Journals (Sweden)

    M. Quiroga

    2008-06-01

    Full Text Available This study was performed to determine the susceptibility patterns and the colonization rate of Group B Streptococcus (GBS in a population of pregnant women. From January 2004 to December 2006, vaginal-rectal swabs were obtained from 1105 women attending Dr. Ramón Madariaga Hospital, in Posadas, Misiones, Argentina. The carriage rate of GBS among pregnant women was 7.6%. A total of 62 GBS strains were randomly selected for in vitro susceptibility testing to penicillin G, ampicillin, tetracycline, levofloxacin, gatifloxacin, ciprofloxacin, quinupristin-dalfopristin, linezolid, vancomycin, rifampicin, trimethoprim-sulfametoxazol, nitrofurantoin, gentamicin, clindamycin and erythromycin, and determination of resistance phenotypes. No resistance to penicillin, ampicillin, quinupristin-dalfopristin, linezolid, and vancomycin was found. Of the isolates examined 96.8%, 98.3%, 46.8%, and 29.0% were susceptible to rifampicin, nitrofurantoin, trimethoprim-sulfametoxazol and tetracycline, respectively. Rank order of susceptibility for the quinolones was: gatifloxacin (98.4% > levofloxacin (93.5% > ciprofloxacin (64.5%. The rate of resistance to erythromycin (9.7% was higher than that of other reports from Argentina. High-level resistance to gentamicin was not detected in any of the isolates. Based on our finding of 50% of GBS isolates with MIC to gentamicin equal o lower than 8 µg/ml, a concentration used in one of the selective media recommended for GBS isolation, we suggested, at least in our population, the use of nalidixic acid and colistin in selective media with the aim to improve the sensitivity of screening cultures for GBS carriage in women.Esse estudo objetivou determinar os padrões de sensibilidade a antibióticos e as taxas de colonização de Streptococcus do grupo B (GBS em uma população de mulheres grávidas. Entre janeiro de 2004 e dezembro de 2006, foram obtidos swabs vaginais-retais de 1105 mulheres no Hospital Dr. Ramon Madariaga, em

  8. Crystal Structure of the N-terminal Domain of the Group B Streptococcus Alpha C Protein

    Energy Technology Data Exchange (ETDEWEB)

    Auperin,T.; Bolduc, G.; Baron, M.; Heroux, A.; Filman, D.; Madoff, L.; Hogle, J.

    2005-01-01

    Group B Streptococcus (GBS) is the leading cause of bacterial pneumonia, sepsis, and meningitis among neonates and an important cause of morbidity among pregnant women and immunocompromised adults. Invasive diseases due to GBS are attributed to the ability of the pathogen to translocate across human epithelial surfaces. The alpha C protein (ACP) has been identified as an invasin that plays a role in internalization and translocation of GBS across epithelial cells. The soluble N-terminal domain of ACP (NtACP) blocks the internalization of GBS. We determined the 1.86-{angstrom} resolution crystal structure of NtACP comprising residues Ser{sup 52} through Leu{sup 225} of the full-length ACP. NtACP has two domains, an N-terminal {beta}-sandwich and a C-terminal three-helix bundle. Structural and topological alignments reveal that the {beta}-sandwich shares structural elements with the type III fibronectin fold (FnIII), but includes structural elaborations that make it unique. We have identified a potential integrin-binding motif consisting of Lys-Thr-Asp{sup 146}, Arg{sup 110}, and Asp{sup 118}. A similar arrangement of charged residues has been described in other invasins. ACP shows a heparin binding activity that requires NtACP. We propose a possible heparin-binding site, including one surface of the three-helix bundle, and nearby portions of the sandwich and repeat domains. We have validated this prediction using assays of the heparin binding and cell-adhesion properties of engineered fragments of ACP. This is the first crystal structure of a member of the highly conserved Gram-positive surface alpha-like protein family, and it will enable the internalization mechanism of GBS to be dissected at the atomic level.

  9. GROUP-B STREPTOCOCCUS IN PREGNANT WOMEN: Prevalence of Colonization and Sensitivity Pattern in Denpasar during June 2007May 2008

    Directory of Open Access Journals (Sweden)

    N Sri-Budayanti

    2013-01-01

    Full Text Available Objective: Group-B Streptococci (GBS are Gram-positive cocci that are the most common cause of early onset neonatal sepsis. The mortality rate of early onset neonatal sepsis has been reported up to 50%. One of the major risks of early onset neonatal sepsis is GBS colonization in birthcanal of pregnant women that can infect the baby during process of vaginal delivery. Antibiotic chemoprophylaxis for pregnant women that is colonized by GBS can reduce the risk of early onset neonatal sepsis. The detection of GBS colonization needs Todd Hewitt (TH enrichment medium toreduce false negative result. Until now, there is no report about either prevalence of colonization or sensitivity pattern of Group B Streptococcus among pregnant women in Denpasar. The aims of this research were to determine the prevalence of GBS colonization and sensitivity pattern of GBS amongpregnant women with Todd Hewitt enrichment medium.Method: This research was a descriptive cross-sectional study. Vaginal swab specimens from 3537 weeks gestation pregnant women were collected and 32 samples that met the inclusion criteria were cultured on Blood agar (BA plates, Chromagar (CA plates, and Todd Hewitt (TH broth. The GBS colonization that grew in culture medium was followed by antibiotic sensitivity test.Results: In the present study, we found that the prevalence of GBS colonization in pregnant women detected with culture method using BA and CA without TH broth was 9.4%, whereas the prevalence with culture method using BA and CA enriched by TH broth was 31.3%. Moreover, GBS showed resistance to penicillin, erythromycin, and cefazolin. It is indicated that TH enrichment medium seems to be promising as a screening method for GBS colonization in pregnant women in Bali.Conclusion: There was an enrichment detection of GBS prevalence colonization in pregnant women detected the swab with culture method using BA and CA enriched by TH compare to BA and CA without TH broth

  10. Vertical transmission of group B Streptococcus and associated factors among pregnant women: a cross-sectional study, Eastern Ethiopia

    Directory of Open Access Journals (Sweden)

    Yadeta TA

    2018-03-01

    Full Text Available Tesfaye Assebe Yadeta,1 Alemayehu Worku,2 Gudina Egata,3 Berhanu Seyoum,4 Dadi Marami,4 Yemane Berhane5 1School of Nursing and Midwifery, College of Health and Medical Sciences, Haramaya University, Harar, Ethiopia; 2Department of Epidemiology and Biostatistics, School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia; 3School of Public Health, College of Health and Medical Sciences, Haramaya University, Harar, Ethiopia; 4Department of Medical Laboratory Science, College of Health and Medical Sciences, Haramaya University, Harar, Ethiopia; 5Department of Epidemiology, Addis Continental Institute of Public Health, Addis Ababa, Ethiopia Background: Vertically transmitted group B Streptococcus (GBS causes fetal and neonatal infections. However, there is limited information on the vertical transmission of GBS in low-income countries. This study, therefore, aimed to determine the rate of vertical transmission of GBS and associated factors among pregnant women in Eastern Ethiopia.Subjects and methods: A cross-sectional, facility-based study was conducted among pregnant women in Harar town, Eastern Ethiopia, from June to October, 2016. GBS positivity of pregnant women was confirmed by culture of rectovaginal swab. Vertical transmission at birth was confirmed by culture on swabs taken from the ear canal, umbilicus, axilla, groin, and nose within 6 hours after birth. Prevalence ratio (PR along with 95% CI was estimated to examine factors associated with vertical transmission using log binomial regression analysis.Results: Out of 231 GBS-colonized pregnant women at delivery, 104 births were identified as GBS colonized with a vertical transmission rate of 45.02% and 95% CI: 38.49, 51.68. Of 104 vertical transmission cases, 65 (62.50% received no intrapartum antibiotic prophylaxis (IAP, 28 (26.92% received it <4 hours before delivery, and 11 (10.58% received it ≥4 hours before delivery. Pre-labor rupture of membranes at term (PR: 1.93; 95

  11. Comparative evaluation of Strepto B ID chromogenic medium and Granada media for the detection of Group B streptococcus from vaginal samples of pregnant women.

    Science.gov (United States)

    Tazi, Asmaa; Réglier-Poupet, Hélène; Dautezac, François; Raymond, Josette; Poyart, Claire

    2008-06-01

    Two types of selective media, the chromogenic medium Strepto B ID and two non-chromogenic media Strepto B agar and the Granada medium, were tested and compared to blood agar plates (BAP) for screening of Group B streptococcus vaginal colonization in pregnant women. All tested media were comparable in terms of sensitivity however, their use in routine laboratories may markedly facilitate the rapid detection of GBS in vaginal samples.

  12. Phenotypic and genotypic antimicrobial susceptibility pattern of Streptococcus spp. isolated from cases of clinical mastitis in dairy cattle in Poland.

    Science.gov (United States)

    Kaczorek, E; Małaczewska, J; Wójcik, R; Rękawek, W; Siwicki, A K

    2017-08-01

    Mastitis of dairy cattle is one of the most frequently diagnosed diseases worldwide. The main etiological agents of mastitis are bacteria of the genus Streptococcus spp., in which several antibiotic resistance mechanisms have been identified. However, detailed studies addressing this problem have not been conducted in northeastern Poland. Therefore, the aim of our study was to analyze, on phenotypic and genotypic levels, the antibiotic resistance pattern of Streptococcus spp. isolated from clinical cases of mastitis from dairy cattle in this region of Poland. The research was conducted using 135 strains of Streptococcus (Streptococcus uberis, n = 53; Streptococcus dysgalactiae, n = 41; Streptococcus agalactiae, n = 27; other streptococci, n = 14). The investigation of the antimicrobial susceptibility to 8 active substances applied in therapy in the analyzed region, as well as a selected bacteriocin (nisin), was performed using the minimum inhibitory concentration method. The presence of selected resistance genes (n = 14) was determined via PCR. We also investigated the correlation between the presence of resistance genes and the antimicrobial susceptibility of the examined strains in vitro. The highest observed resistance of Streptococcus spp. was toward gentamicin, kanamycin, and tetracycline, whereas the highest susceptibility occurred toward penicillin, enrofloxacin, and marbofloxacin. Additionally, the tested bacteriocin showed high efficacy. The presence of 13 analyzed resistance genes was observed in the examined strains [gene mef(A) was not detected]. In most strains, at least one resistance gene, mainly responsible for resistance to tetracyclines [tet(M), tet(K), tet(L)], was observed. However, a relationship between the presence of a given resistance gene and antimicrobial susceptibility on the phenotypic level was not always observed. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Septicemia with Streptococcus pseudopneumoniae

    DEFF Research Database (Denmark)

    Fuursted, Kurt; Littauer, Pia Jeanette; Greve, Thomas

    2016-01-01

    Streptococcus pseudopneumoniae was described in 2004 as a new human pathogen, acknowledged in a range of clinical infections typically associated to the respiratory tract. This report demonstrates that S. pseudopneumoniae has the potential to cause invasive infection. In blood cultures from three...... and the antibiogram and resistome revealed no antibiotic resistance....

  14. Bacteremia with Streptococcus pneumoniae

    DEFF Research Database (Denmark)

    Christensen, J S; Jensen, T G; Kolmos, H J

    2012-01-01

    We conducted a hospital-based cohort study among adult patients with first-time Streptococcus pneumoniae bacteremia (SPB) from 2000 through 2008. Patients were identified in a population-based bacteremia database and followed up for mortality through the Danish Civil Registration System (CRS...

  15. Infecção congênita em cabritos por Mycoplasma agalactiae

    Directory of Open Access Journals (Sweden)

    N.S. Silva

    2014-04-01

    Full Text Available This study aimed to report three cases of contagious agalactia (CA by Mycoplasma agalactiae in goat kids born with polyarthritis. The nanny goats belonging to two different herds presented clinical signs of CA during pregnancy and in parturition they were apparently healthy. The carpal articulations of the three goat kids, the tarsus articulation in one, and thigh-femoral articulation in another showed swelling, pain and impairment of the flexion-extension movements. The articular liquid was collected from two goat kids at birth and revealed a content which varied from transparent to fibrinopurulent, presenting a yellow coloring. The samples were plated on modified Hayflick. The colonies had the appearance of "fried egg" and were confirmed as being M. agalactiae by biochemical tests and 16S rRNA PCR. Blood was collected from three animals soon after birth and submitted to the indirect ELISA test for the determination of the titration of the anti- M. agalactiae antibodies. The results confirmed that the goat kids were infected during pregnancy by M. agalactiae and resulted in the birth of an offspring with clinical signs of CA being immune tolerant.

  16. Low-cost and miniaturized 100-Gb/s (2 × 50 Gb/s) PAM-4 TO-packaged ROSA for data center networks.

    Science.gov (United States)

    Kang, Sae-Kyoung; Huh, Joon Young; Lee, Jie Hyun; Lee, Joon Ki

    2018-03-05

    We design and implement a cost-effective and compact 100-Gb/s (2 × 50 Gb/s) PAM-4 receiver optical sub-assembly (ROSA) by using a TO-can package instead of an expensive box-type package. It consists of an optical demultiplexer, two PIN-PDs and a 2-channel linear transimpedance amplifier. The components are passively aligned and assembled using alignment marks engraved on each part. With a real-time PAM-4 DSP chip, we measured the back-to-back receiver sensitivities of the 100-Gb/s ROSA based on TO-56 to be less than -13.2 dBm for both channels at a bit error rate of 2.4e-4. The crosstalk penalty due to the adjacent channel interference was observed around 0.1 dB.

  17. Selective versus non-selective culture medium for group B streptococcus detection in pregnancies complicated by preterm labor or preterm-premature rupture of membranes

    Directory of Open Access Journals (Sweden)

    Marcelo Luís Nomura

    Full Text Available The objective of this study was to identify group B streptococcus (GBS colonization rates and compare detection efficiency of selective versus non-selective culture media and anorectal versus vaginal cultures in women with preterm labor and preterm-premature rupture of membranes (PROM. A prospective cohort study of 203 women was performed. Two vaginal and two anorectal samples from each woman were collected using sterile swabs. Two swabs (one anorectal and one vaginal were placed separately in Stuart transport media and cultured in blood-agar plates for 48 hours; the other two swabs were inoculated separately in Todd-Hewitt selective media for 24 hours and then subcultured in blood-agar plates. Final GBS identification was made by the CAMP test. A hundred thrity-two cultures out of 812 were positive. The maternal colonization rate was 27.6%. Colonization rates were 30% for preterm PROM and 25.2% for preterm labor. Todd-Hewitt selective medium detected 87.5% and non-selective medium 60.7% GBS-positive women. Vaginal samples and anorectal samples had the same detection rate of 80.3%. Anorectal selective cultures detected 75% of carriers; 39% of GBS-positive women were detected only in selective medium. A combined vaginal-anorectal selective culture is appropriate for GBS screening in this population, minimizing laboratory costs.

  18. Development of real-time PCR for detection and quantitation of Streptococcus parauberis.

    Science.gov (United States)

    Nguyen, T L; Lim, Y J; Kim, D-H; Austin, B

    2016-01-01

    Streptococcus parauberis is an increasing threat to aquaculture of olive flounder, Paralichthys olivaceus Temminck & Schlegel, in South Korea. We developed a real-time polymerase chain reaction (PCR) method using the TaqMan probe assay to detect and quantify S. parauberis by targeting the gyrB gene sequences, which are effective for molecular analysis of the genus Streptococcus. Our real-time PCR assay is capable of detecting 10 fg of genomic DNA per reaction. The intra- and interassay coefficient of variation (CV) values ranged from 0.42-1.95%, demonstrating that the assay has good reproducibility. There was not any cross-reactivity to Streptococcus iniae or to other streptococcal/lactococcal fish pathogens, such as S. agalactiae and Lactococcus garvieae, indicating that the assay is highly specific to S. parauberis. The results of the real-time PCR assay corresponded well to those of conventional culture assays for S. parauberis from inoculated tissue homogenates (r = 0.957; P < 0.05). Hence, this sensitive and specific real-time PCR is a valuable tool for diagnostic quantitation of S. parauberis in clinical samples. © 2014 John Wiley & Sons Ltd.

  19. Radioimmunoassay of serum antibodies with B-streptococcus specificity in pregnant women and infants

    International Nuclear Information System (INIS)

    Frey, C.W.

    1980-01-01

    In a specific competitive radioimmunoassay of purified rabbit antibodies, labeled with iodine 125 against group- and type-antigens of streptococcus agalactiae (streptococci type B), we investigated the amount of serum anti-bodies providing specificity of streptococci type B in not preselected pregnant women, newborn and babies with colonies of streptococci type B or with diseases due to streptococci type B and in some of their mothers. These antibodies could be detected in 26 of 45 pregnant women and in 3 of 7 children with colonies of streptococci type B. 5 of 18 newborn with the ''early-onset'' type of infection and 6 of 7 of their mothers provided antibodies with specificity of streptococci type B as did one of two newborn with the ''late onset'' type of infection. Contrary to the supposition of Baker and Kasper and in accordance with the findings of Wilkinson, the ''risk group'' cannot be determined only by detecting the antibodies against streptococci type B. The risk group comprises those persons in whom the colonisation of streptococci agalactiae leads to the frequently life-threatening infecton of neonatals with streptococci type B. (orig.) [de

  20. 10 Gb/s bidirectional single fibre long reach PON link with distributed Raman amplification

    DEFF Research Database (Denmark)

    Tafur Monroy, Idelfonso; Kjær, Rasmus; Jeppesen, Palle

    2006-01-01

    We report operation of a single fibre bidirectional 80 km long reach PON link with symmetric up- and-downstream data rate of 10 Gb/s supported by distributed Raman fibre amplification only.......We report operation of a single fibre bidirectional 80 km long reach PON link with symmetric up- and-downstream data rate of 10 Gb/s supported by distributed Raman fibre amplification only....

  1. Phase Modulation for postcompensation of dispersion in 160-Gb/s systems

    DEFF Research Database (Denmark)

    Siahlo, Andrei; Clausen, A. T.; Oxenløwe, Leif Katsuo

    2005-01-01

    Tunable postcompensation of second-order dispersion by sinusoidal phase modulation is realized for a 160-Gb/s optical transmission system. Accumulated dispersions with magnitudes up to 4 ps/nm are compensated in the receiver end.......Tunable postcompensation of second-order dispersion by sinusoidal phase modulation is realized for a 160-Gb/s optical transmission system. Accumulated dispersions with magnitudes up to 4 ps/nm are compensated in the receiver end....

  2. 160 Gb/s Raman-assisted notch-filtered XPM wavelength conversion and transmission

    DEFF Research Database (Denmark)

    Galili, Michael; Oxenløwe, Leif Katsuo; Mulvad, Hans Christian Hansen

    2007-01-01

    In-line wavelength conversion of 160 Gb/s data by Raman-assisted notch-filtered XPM is demonstrated for 130 km total transmission. The improvement in system performance from applying Raman gain during conversion is shown.......In-line wavelength conversion of 160 Gb/s data by Raman-assisted notch-filtered XPM is demonstrated for 130 km total transmission. The improvement in system performance from applying Raman gain during conversion is shown....

  3. BRAINSTEM AUDITORY EVOKED POTENTIAL AS AN INDEX OF CNS DEMYELINATION IN GUILLAIN -BARRÉ SYNDROME (GBS

    Directory of Open Access Journals (Sweden)

    Smita Singh

    2016-01-01

    Full Text Available Background: Guillain-Barré Syndrome (GBS is an acute, frequently severe and fulminant polyradicular neuropathy that is autoimmune in nature. GBS manifest as rapidly evolving areflexic motor paralysis with or without sensory disturbances. It mainly involves peripheral nervous system and autonomic nervous system. There are rare evidences about the involvement of central nervous system (CNS in GBS. Aims: The main objective of the study was to assess the CNS involvement in GBS using the Brainstem Auditory Evoked Potential (BAEP. Methods & Material: The study was conducted in the clinical neurophysiology lab in the department of physiology, CSMMU Lucknow. Study group involved 26 subjects (n=26 having GBS and control group involved 30 normal subjects (n=30. BAEPS were recorded by Neuroperfect- EMG 2000 EMG/NCV/EPsytem. The data so obtained were subjected to analysis using Statistical Package for Social Sciences (SPSS Version 13.0. Results & Conclusions: There was significant increase in PIII & PV peak latencies and PI-PIII & PI-PV interpeak latencies in both left and right ear in the study group, which showed the CNS involvement in GBS which can be assessed using BAEP.

  4. Management of group b streptococcus-positive pregnant women at maternity homes in JAPAN: a questionnaire survey of compliance among midwives.

    Science.gov (United States)

    Yamaguchi, Kotomi; Ohashi, Kazutomo

    2018-01-01

    Per the 2014 Japanese Midwives Association (JMA) guidelines, midwives were allowed to manage the deliveries for group B streptococcus (GBS)-positive pregnant women in labour at maternity homes without the supervision of a medical doctor if they complied with the guidelines of the Japan Society of Obstetrics and Gynecology (JSOG), wherein midwives working for maternity homes are expected to cooperate with commissioned obstetricians and paediatricians in cooperative medical facilities. We examined the rate of compliance with these JMA and JSOG guidelines regarding the management of GBS-positive pregnant women among midwives at maternity homes in Japan. Between October and December 2015, an anonymous questionnaire was distributed to 337 maternity homes registered with the JMA by mail. The questionnaire obtained information regarding the timing of GBS screening, specimen collection, transfer of GBS-positive pregnant women from a maternity home to a hospital, administration of intrapartum antibiotic prophylaxis, and collaboration between midwives and commissioned obstetricians. Data were analysed using descriptive statistics. We used frequency distribution as the statistical test. Responses were received from 246 (73.0%) maternity homes, of which complete responses from 204 maternity homes (valid response rate, 60.5%) were analysed. Of these 204 maternity homes, only 97 (47.5%) conducted a GBS screening test during 33-37 weeks of gestation as recommended by the JSOG guidelines. Although midwives alone managed GBS-positive pregnant women in labour at 135 maternity homes (66.2%), intrapartum antibiotic prophylaxis, as recommended by the JSOG guidelines, was conducted in only 111 (54.4%). Moreover, only 37.0% (50/135) and 82.2% (111/135) of maternity homes ensured that GBS-positive pregnant women in labour with an elapse of ≥18 h after PROM and a body temperature of ≥38.0 °C, respectively, were transferred to a hospital by ambulance. Only at 58.3% (119/204) of

  5. 10 Gb/s OEIC optical receiver front-end and 3.125 Gb/s PHEMT limiting amplifier

    International Nuclear Information System (INIS)

    Fan Chao; Jiao Shilong; Wu Yunfeng; Ye Yutang; Chen Tangsheng; Yang Lijie; Feng Ou

    2009-01-01

    A 10 Gb/s OEIC (optoelectronic integrated circuit) optical receiver front-end has been studied and fabricated based on the Φ-76 mm GaAs PHEMT process; this is the first time that a limiting amplifier (LA) has been designed and realized using depletion mode PHEMT. An OEIC optical receiver front-end mode composed of an MSM photodiode and a current mode transimpedance amplifier (TIA) has been established and optimized by simulation software ATLAS. The photodiode has a bandwidth of 10 GHz, a capacitance of 3 fF/μm and a photosensitive area of 50 x 50 μm 2 . The whole chip has an area of 1511 x 666 μm 2 . The LA bandwidth is expanded by spiral inductance which has been simulated by software HFSS. The chip area is 1950 x 1910 μm 2 and the measured results demonstrate an input dynamic range of 34 dB (10-500 mVpp) with constant output swing of 500 mVpp.

  6. 10 Gb/s OEIC optical receiver front-end and 3.125 Gb/s PHEMT limiting amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Fan Chao; Jiao Shilong; Wu Yunfeng; Ye Yutang [School of Opto-Electronic Information, UESTC, Chengdu 610054 (China); Chen Tangsheng; Yang Lijie; Feng Ou, E-mail: fanchao41@126.co [Nanjing Electronic Devices Institute, Nanjing 210016 (China)

    2009-10-15

    A 10 Gb/s OEIC (optoelectronic integrated circuit) optical receiver front-end has been studied and fabricated based on the {Phi}-76 mm GaAs PHEMT process; this is the first time that a limiting amplifier (LA) has been designed and realized using depletion mode PHEMT. An OEIC optical receiver front-end mode composed of an MSM photodiode and a current mode transimpedance amplifier (TIA) has been established and optimized by simulation software ATLAS. The photodiode has a bandwidth of 10 GHz, a capacitance of 3 fF/{mu}m and a photosensitive area of 50 x 50 {mu}m{sup 2}. The whole chip has an area of 1511 x 666 {mu}m{sup 2}. The LA bandwidth is expanded by spiral inductance which has been simulated by software HFSS. The chip area is 1950 x 1910 {mu}m{sup 2} and the measured results demonstrate an input dynamic range of 34 dB (10-500 mVpp) with constant output swing of 500 mVpp.

  7. Epidemiology of Mycoplasma agalactiae and Mycoplasma mycoides cluster in flocks of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Sandra Batista dos Santos

    2018-04-01

    Full Text Available ABSTRACT: The present study aimed to investigate contagious agalactia (CA in flocks from Pernambuco State. The study involved 225 goats and 63 ewes; 288 milk samples and 100 vaginal swabs were collected in total. The PCR assays were carried out using specific primers to Mycoplasma agalactiae and the Mycoplasma mycoides cluster. Among the goat’s milk samples,12.0% (27/225 were positive for Mycoplasma agalactiae DNA, while 5.3% (12/225 contained the Mycoplasma mycoides cluster. Of the vaginal swabs taken from goats, 15.4% (12/78 were positive for Mycoplasma agalactiae DNA and 3.8% (3/78 contained the Mycoplasma mycoides cluster. In the case of ewes, 4.3% (1/23 of the milk samples contained Mycoplasma agalactiae DNA, and 7.5% (3/40 were positive for the Mycoplasma mycoides cluster. Vaginal swabs taken from sheep´s were negative. Analysis of risk factors for mycoplasmosis, showed that goats and sheep flocks on the extensive breeding system are more likely to have mycoplasmosis than those on the intensive breeding system (odds ratio (OR 6.2; p=0.004; meat goat and sheep flocks are more likely to have infection compared to dairy flocks (OR 4.8; p=0.011; unclean animal housing increases the chances of infection (OR 5.0; p=0.031 and not performing quarantine increases the chances of mycoplasmosis (OR 4.6; p=0.042. Based on these findings we conclude that CA syndrome in the semiarid region of Pernambuco state can be associated with Mycoplasma agalactiae and Mycoplasma mycoides cluster.

  8. Group B Streptococcus prophylaxis in patients who report a penicillin allergy: a follow-up study.

    Science.gov (United States)

    Critchfield, Agatha S; Lievense, Stacey P; Raker, Christina A; Matteson, Kristen A

    2011-02-01

    The purpose of this study was to compare adherence to the 2002 Centers for Disease Control (CDC) guidelines for the prevention of perinatal group B Streptococcus (GBS) disease in patients who are allergic to penicillin during the years 2004-2006 and 2008. Previous data from our institution revealed suboptimal adherence to the 2002 CDC guidelines for GBS prophylaxis among women who are allergic to penicillin. These data caused the hospital to implement a series of interventions. The original cohort (2004-2006) was compared with a cohort of women who delivered between April 2008 and January 2009 (n = 74) to determine whether the proportion of women who had antimicrobial sensitivity testing and who had received an appropriate antibiotic had improved. In 2008, 76% (95% confidence interval, 66-84%) of GBS-positive women who are allergic to penicillin received an appropriate antibiotic (compared with 16.2% in 2004-2006; P sensitivity testing was performed in 79.4% of cases (95% confidence interval, 68-87%), compared with 11.4% in 2004-2006 (P penicillin improved dramatically. Copyright © 2011 Mosby, Inc. All rights reserved.

  9. Virulence Factors of Streptococcus mutans.

    Science.gov (United States)

    1986-08-01

    763512/715242 Final Report U VIRULENCE FACTORS OF STREPTOCOCCUS MUTANS U Samuel Rosen Department of Oral Biology For the Period April 1, 1983 - June 30...00 FINAL REPORT VIRULENCE FACTORS OF STREPTOCOCCUS MUTANS Sam Rosen, Irving Shklair, E. X. Beck and F. M. Beck Ohio State University Columbus,Oh and...206-212. Johnson CP, Gorss S, Hillman JD (1978). Cariogenic properties of LDH deficient mutants of streptococcus mutans . J Dent Res 57, Special Issue

  10. PENAPISAN ISOLAT BAKTERI Streptococcus spp. SEBAGAI KANDIDAT ANTIGEN DALAM PEMBUATAN VAKSIN, SERTA EFIKASINYA UNTUK PENCEGAHAN PENYAKIT STREPTOCOCCOSIS PADA IKAN NILA, Oreochromis niloticus

    Directory of Open Access Journals (Sweden)

    Taukhid Taukhid

    2011-04-01

    Full Text Available Riset dengan tujuan untuk memperoleh isolat kandidat yang imunogenik bagi pembuatan vaksin untuk pengendalian penyakit streptococcosis pada ikan nila telah dilakukan. Karakterisasi dilakukan secara biokimia dan API 20 STREP terhadap 15 isolat bakteri Streptococcus spp. Uji Koch’s Postulate kemudian dilakukan untuk mengetahui peran bakteri pada infeksi streptococcosis pada ikan nila. Konfirmasi taksonomis hingga level spesies isolat bakteri S. agalactiae dilakukan dengan teknik Polymerase Chain Reaction (PCR dengan menggunakan primer spesifik. Uji patogenisitas dilakukan terhadap 6 isolat yang terdiri atas 5 isolat S. agalactiae (N3M, N4M, N14G, N17O, NK1 dan 1 isolat S. iniae (N2O. Hasil penapisan menunjukkan bahwa bakteri S. agalactiae (N4M memiliki nilai LD50 terkecil, dan nilai terbesar dimiliki oleh bakteri S. iniae (N2O. Isolat bakteri N4M digunakan sebagai sumber antigen dalam pembuatan vaksin anti streptococcosis. Vaksin disiapkan dalam bentuk sel utuh dan diinaktivasi dengan formalin, pemanasan, dan sonikasi. Nilai titer antibodi dan sintasan tertinggi diperoleh pada kelompok ikan yang divaksin dengan formalin killed vaccine dibandingkan dengan teknik inaktivasi lainnya (heat killed vaccine dan sonicated vaccine.

  11. Characterization of a Streptococcus suis tet(O/W/32/O)-carrying element transferable to major streptococcal pathogens.

    Science.gov (United States)

    Palmieri, Claudio; Magi, Gloria; Mingoia, Marina; Bagnarelli, Patrizia; Ripa, Sandro; Varaldo, Pietro E; Facinelli, Bruna

    2012-09-01

    Mosaic tetracycline resistance determinants are a recently discovered class of hybrids of ribosomal protection tet genes. They may show different patterns of mosaicism, but their final size has remained unaltered. Initially thought to be confined to a small group of anaerobic bacteria, mosaic tet genes were then found to be widespread. In the genus Streptococcus, a mosaic tet gene [tet(O/W/32/O)] was first discovered in Streptococcus suis, an emerging drug-resistant pig and human pathogen. In this study, we report the molecular characterization of a tet(O/W/32/O) gene-carrying mobile element from an S. suis isolate. tet(O/W/32/O) was detected, in tandem with tet(40), in a circular 14,741-bp genetic element (39.1% G+C; 17 open reading frames [ORFs] identified). The novel element, which we designated 15K, also carried the macrolide resistance determinant erm(B) and an aminoglycoside resistance four-gene cluster including aadE (streptomycin) and aphA (kanamycin). 15K appeared to be an unstable genetic element that, in the absence of recombinases, is capable of undergoing spontaneous excision under standard growth conditions. In the integrated form, 15K was found inside a 54,879-bp integrative and conjugative element (ICE) (50.5% G+C; 55 ORFs), which we designated ICESsu32457. An ∼1.3-kb segment that apparently served as the att site for excision of the unstable 15K element was identified. The novel ICE was transferable at high frequency to recipients from pathogenic Streptococcus species (S. suis, Streptococcus pyogenes, Streptococcus pneumoniae, and Streptococcus agalactiae), suggesting that the multiresistance 15K element can successfully spread within streptococcal populations.

  12. Isolation and characterization of Streptococcus spp. group B in Nile tilapias (Oreochromis niloticus reared in hapas nets and earth nurseries in the northern region of Parana State, Brazil

    Directory of Open Access Journals (Sweden)

    Salvador Rogério

    2005-01-01

    Full Text Available The objective of this study was to isolate and characterize Streptococcus spp. in Nile tilapias (Oreochromis niloticus reared in net-pens and earth nurseries. Eight intensive tilapia-rearing farms were investigated in north Paraná, Brazil from April 1st 2001 to April 30th 2002. The fish were reared in a system of hapas nets on four farms and in earth nurseries on other four farms. A total of 370 samples were analyzed of material collected from 120 fish (brain, liver, kidney, skin scrapes, ascites liquid and eye that were sown on BHI agar (Brain Heart Infusion supplemented with 1% yeast extract and sheep blood. Streptococcus spp. was isolated in 36 of the samples (18 brain, eight liver, eight kidney and two ascites liquid from 25 fish. Streptococci were isolated in both systems, almost in the same proportion. First the streptococci were characterized by the catalase and esculin test, growth in methylene blue and sodium chloride at 6.5%. They were classified in groups by the Slidex Strepto-Kit (BioMerieux, France. The phenotypic characteristics were determined by the Api 20 Strep microtest system (BioMerieux, France. The 36 Streptococcus spp. samples did not present hemolysis and were classified as Lancefield group B. Further 16 samples were identified as Streptococcus agalactiae and 20 were not identified by the Api 20 Strep, but presented the same biochemical profile described for the reference strain of Streptococcus difficile (ND-2-22.

  13. Screening for group B Streptococcus in pregnant women: a systematic review and meta-analysis Rastreo de Streptococcus del grupo B en gestantes: revisión sistemática y metanálisis Rastreamento de Streptococcus do grupo B em gestantes: revisão sistemática e metanálise

    Directory of Open Access Journals (Sweden)

    Mônica Taminato

    2011-12-01

    Full Text Available Infection with Group B Streptococcus (GBS is considered an important public health problem. It is associated with: Neonatal sepsis, meningitis, pneumonia, neonatal death, septic abortion, chorioamnionitis, endometritis and other perinatal infections. The aim of this study was to determine the best screening strategy for GBS in pregnant women. For this a systematic review and meta-analysis were carried out in the Nursing Department of the Federal University of São Paulo, Cochrane Center, Brazil. Sources used were, EMBASE, LILACS, Medline, list of references, personal communication and the Cochrane library. The criterion for the selection of the studies was; studies which analyze some type of screening for GBS in pregnant women. Independent of the comparator, all analyses were in favor of a universal screening program for reducing the incidence of neonatal sepsis. The evidence obtained in this study suggests that the strategy of universal screening of pregnant women associated with the use of prophylactic antibiotics is safe and effective.La infección por Streptococcus del grupo B (GBS es considerada un importante problema de salud pública. Los estreptococos están asociados a: sepsis neonatal, meningitis, neumonía, muerte neonatal, aborto séptico, corioamnionitis, endometritis y otras infecciones perinatales. El objetico del estudio fue determinar la mejor estrategia de rastreo de GBS en gestantes. Se trata de una revisión Sistemática con Metanálisis. Fue realizada en el Departamento de Enfermería de la Universidad Federal de Sao Paulo, Centro Cochrane de Brasil. Se utilizaron las siguientes fuentes: EMBASE, LILACS, Medline, lista de referencias bibliográficas, comunicación personal y Cochrane Library. Como criterio para la selección de los estudios, se escogieron los que analizaron algún tipo de rastreo para GBS en gestantes. Independientemente del comparador, todos los análisis fueron favorables al programa de screening universal

  14. Isolation and identification of Mycoplasma agalactiae by culture and polymerase chain reaction (PCR from sheep of Qom province, Iran

    Directory of Open Access Journals (Sweden)

    Abtin, A.R.

    2013-05-01

    Full Text Available Contagious agalactia (C.A is an infectious syndrome of sheep that is characterized by mastitis andsubsequent failure of milk production, arthritis, abortion and keratoconjunctivitis. Mycoplasma agalactiae(M. agalactiae is the main cause of the disease in sheep. The aim of this study was isolation andidentification of M. agalactiae with culture and polymerase chain reaction (PCR assay from sheep of Qomprovince in Iran. A total of 102 samples were collected from milk secretion, eye, ear and joint exudates ofsheep. All samples were cultured in PPLO broth supplemented for M. agalaciae isolation. The bacteriaDNAs were extracted by phenol/chloroform method and the PCR assay was applied for detecting ofMycoplasma genus in 163bp fragment of 16S rRNA gene and M. agalactiae in 375bp fragment oflipoprotein gene from culture as same as in clinical samples. Out of the 102 samples, 19(18.63% cultureswere shown positive and typical Mycoplasma colonies in PPLO agar culture diagnostic method and59(57.8% were scored positive by Mycoplasma genus PCR, 19(18.62% of the samples were scoredpositive by using M. agalactiae PCR as diagnostic method. Out of the 102 samples, 19 samples wereshown both positive in the culture and PCR, 42 samples were shown both negative in the culture and PCR.40 samples were negative in the culture and positive in PCR whereas only one sample was positive inculture and negative in PCR. The results showed that the more isolations of M. agalactiae were taken from milk and less in joint samples. M. agalactiae was one of the main factors of contagious agalactia that was detected for the first time from sheep in Qom province.

  15. Genetic Transformation of Streptococcus mutans

    OpenAIRE

    Perry, Dennis; Kuramitsu, Howard K.

    1981-01-01

    Three strains of Streptococcus mutans belonging to serotypes a, c, and f were transformed to streptomycin resistance by deoxyribonucleic acids derived from homologous and heterologous streptomycin-resistant strains of S. mutans and Streptococcus sanguis strain Challis. Homologous transformation of S. mutans was less efficient than heterologous transformation by deoxyribonucleic acids from other strains of S. mutans.

  16. Genome characterization and population genetic structure of the zoonotic pathogen, Streptococcus canis

    Directory of Open Access Journals (Sweden)

    Richards Vincent P

    2012-12-01

    Full Text Available Abstract Background Streptococcus canis is an important opportunistic pathogen of dogs and cats that can also infect a wide range of additional mammals including cows where it can cause mastitis. It is also an emerging human pathogen. Results Here we provide characterization of the first genome sequence for this species, strain FSL S3-227 (milk isolate from a cow with an intra-mammary infection. A diverse array of putative virulence factors was encoded by the S. canis FSL S3-227 genome. Approximately 75% of these gene sequences were homologous to known Streptococcal virulence factors involved in invasion, evasion, and colonization. Present in the genome are multiple potentially mobile genetic elements (MGEs [plasmid, phage, integrative conjugative element (ICE] and comparison to other species provided convincing evidence for lateral gene transfer (LGT between S. canis and two additional bovine mastitis causing pathogens (Streptococcus agalactiae, and Streptococcus dysgalactiae subsp. dysgalactiae, with this transfer possibly contributing to host adaptation. Population structure among isolates obtained from Europe and USA [bovine = 56, canine = 26, and feline = 1] was explored. Ribotyping of all isolates and multi locus sequence typing (MLST of a subset of the isolates (n = 45 detected significant differentiation between bovine and canine isolates (Fisher exact test: P = 0.0000 [ribotypes], P = 0.0030 [sequence types], suggesting possible host adaptation of some genotypes. Concurrently, the ancestral clonal complex (54% of isolates occurred in many tissue types, all hosts, and all geographic locations suggesting the possibility of a wide and diverse niche. Conclusion This study provides evidence highlighting the importance of LGT in the evolution of the bacteria S. canis, specifically, its possible role in host adaptation and acquisition of virulence factors. Furthermore, recent LGT detected between S. canis and human

  17. Genome characterization and population genetic structure of the zoonotic pathogen, Streptococcus canis.

    Science.gov (United States)

    Richards, Vincent P; Zadoks, Ruth N; Pavinski Bitar, Paulina D; Lefébure, Tristan; Lang, Ping; Werner, Brenda; Tikofsky, Linda; Moroni, Paolo; Stanhope, Michael J

    2012-12-18

    Streptococcus canis is an important opportunistic pathogen of dogs and cats that can also infect a wide range of additional mammals including cows where it can cause mastitis. It is also an emerging human pathogen. Here we provide characterization of the first genome sequence for this species, strain FSL S3-227 (milk isolate from a cow with an intra-mammary infection). A diverse array of putative virulence factors was encoded by the S. canis FSL S3-227 genome. Approximately 75% of these gene sequences were homologous to known Streptococcal virulence factors involved in invasion, evasion, and colonization. Present in the genome are multiple potentially mobile genetic elements (MGEs) [plasmid, phage, integrative conjugative element (ICE)] and comparison to other species provided convincing evidence for lateral gene transfer (LGT) between S. canis and two additional bovine mastitis causing pathogens (Streptococcus agalactiae, and Streptococcus dysgalactiae subsp. dysgalactiae), with this transfer possibly contributing to host adaptation. Population structure among isolates obtained from Europe and USA [bovine = 56, canine = 26, and feline = 1] was explored. Ribotyping of all isolates and multi locus sequence typing (MLST) of a subset of the isolates (n = 45) detected significant differentiation between bovine and canine isolates (Fisher exact test: P = 0.0000 [ribotypes], P = 0.0030 [sequence types]), suggesting possible host adaptation of some genotypes. Concurrently, the ancestral clonal complex (54% of isolates) occurred in many tissue types, all hosts, and all geographic locations suggesting the possibility of a wide and diverse niche. This study provides evidence highlighting the importance of LGT in the evolution of the bacteria S. canis, specifically, its possible role in host adaptation and acquisition of virulence factors. Furthermore, recent LGT detected between S. canis and human bacteria (Streptococcus urinalis) is cause for concern

  18. Genome characterization and population genetic structure of the zoonotic pathogen, Streptococcus canis

    Science.gov (United States)

    2012-01-01

    Background Streptococcus canis is an important opportunistic pathogen of dogs and cats that can also infect a wide range of additional mammals including cows where it can cause mastitis. It is also an emerging human pathogen. Results Here we provide characterization of the first genome sequence for this species, strain FSL S3-227 (milk isolate from a cow with an intra-mammary infection). A diverse array of putative virulence factors was encoded by the S. canis FSL S3-227 genome. Approximately 75% of these gene sequences were homologous to known Streptococcal virulence factors involved in invasion, evasion, and colonization. Present in the genome are multiple potentially mobile genetic elements (MGEs) [plasmid, phage, integrative conjugative element (ICE)] and comparison to other species provided convincing evidence for lateral gene transfer (LGT) between S. canis and two additional bovine mastitis causing pathogens (Streptococcus agalactiae, and Streptococcus dysgalactiae subsp. dysgalactiae), with this transfer possibly contributing to host adaptation. Population structure among isolates obtained from Europe and USA [bovine = 56, canine = 26, and feline = 1] was explored. Ribotyping of all isolates and multi locus sequence typing (MLST) of a subset of the isolates (n = 45) detected significant differentiation between bovine and canine isolates (Fisher exact test: P = 0.0000 [ribotypes], P = 0.0030 [sequence types]), suggesting possible host adaptation of some genotypes. Concurrently, the ancestral clonal complex (54% of isolates) occurred in many tissue types, all hosts, and all geographic locations suggesting the possibility of a wide and diverse niche. Conclusion This study provides evidence highlighting the importance of LGT in the evolution of the bacteria S. canis, specifically, its possible role in host adaptation and acquisition of virulence factors. Furthermore, recent LGT detected between S. canis and human bacteria (Streptococcus

  19. Genotyping by sequencing (GBS, an ultimate marker-assisted selection (MAS tool to accelerate plant breeding

    Directory of Open Access Journals (Sweden)

    Jiangfeng eHe

    2014-09-01

    Full Text Available Marker-assisted selection (MAS refers to the use of molecular markers to assist phenotypic selections in crop improvement. Several types of molecular markers, such as single nucleotide polymorphism (SNP, have been identified and effectively used in plant breeding. The application of next-generation sequencing (NGS technologies has led to remarkable advances in whole genome sequencing, which provides ultra-throughput sequences to revolutionize plant genotyping and breeding. To further broaden NGS usages to large crop genomes such as maize and wheat, genotyping by sequencing (GBS has been developed and applied in sequencing multiplexed samples that combine molecular marker discovery and genotyping. GBS is a novel application of NGS protocols for discovering and genotyping SNPs in crop genomes and populations. The GBS approach includes the digestion of genomic DNA with restriction enzymes followed by the ligation of barcode adapter, PCR amplification and sequencing of the amplified DNA pool on a single lane of flow cells. Bioinformatic pipelines are needed to analyze and interpret GBS datasets. As an ultimate MAS tool and a cost-effective technique, GBS has been successfully used in implementing genome-wide association study (GWAS, genomic diversity study, genetic linkage analysis, molecular marker discovery and genomic selection (GS under a large scale of plant breeding programs.

  20. Meningitis por Streptococcus suis

    OpenAIRE

    Geffner Sclarsky, D. E.; Moreno Muñoz, R.; Campillo Alpera, Mª.S.; Pardo Serrano, F.J.; Gómez Gómez, A.; Martínez-Lozano, Mª.D.

    2001-01-01

    La infección humana por Streptococcus suis (S. suis) es una zoonosis, con un riesgo ocupacional conocido y que suele presentarse como meningitis purulenta, que tiene baja mortalidad y frecuentes secuelas de hipoacusia y ataxia. Se han publicado menos de 150 casos humanos desde el informe original de hace 30 años. Hay una reconocida distribución geográfica viviendo la mayoría de los afectados en el norte de Europa y el sudeste Asiático. En España se han comunicado dos pacientes con enfermedad ...

  1. Novel IgG-Degrading Enzymes of the IgdE Protease Family Link Substrate Specificity to Host Tropism of Streptococcus Species.

    Science.gov (United States)

    Spoerry, Christian; Hessle, Pontus; Lewis, Melanie J; Paton, Lois; Woof, Jenny M; von Pawel-Rammingen, Ulrich

    2016-01-01

    Recently we have discovered an IgG degrading enzyme of the endemic pig pathogen S. suis designated IgdE that is highly specific for porcine IgG. This protease is the founding member of a novel cysteine protease family assigned C113 in the MEROPS peptidase database. Bioinformatical analyses revealed putative members of the IgdE protease family in eight other Streptococcus species. The genes of the putative IgdE family proteases of S. agalactiae, S. porcinus, S. pseudoporcinus and S. equi subsp. zooepidemicus were cloned for production of recombinant protein into expression vectors. Recombinant proteins of all four IgdE family proteases were proteolytically active against IgG of the respective Streptococcus species hosts, but not against IgG from other tested species or other classes of immunoglobulins, thereby linking the substrate specificity to the known host tropism. The novel IgdE family proteases of S. agalactiae, S. pseudoporcinus and S. equi showed IgG subtype specificity, i.e. IgdE from S. agalactiae and S. pseudoporcinus cleaved human IgG1, while IgdE from S. equi was subtype specific for equine IgG7. Porcine IgG subtype specificities of the IgdE family proteases of S. porcinus and S. pseudoporcinus remain to be determined. Cleavage of porcine IgG by IgdE of S. pseudoporcinus is suggested to be an evolutionary remaining activity reflecting ancestry of the human pathogen to the porcine pathogen S. porcinus. The IgG subtype specificity of bacterial proteases indicates the special importance of these IgG subtypes in counteracting infection or colonization and opportunistic streptococci neutralize such antibodies through expression of IgdE family proteases as putative immune evasion factors. We suggest that IgdE family proteases might be valid vaccine targets against streptococci of both human and veterinary medical concerns and could also be of therapeutic as well as biotechnological use.

  2. A microwave-irradiated Streptococcus agalactiae vaccine provides partial protection against experimental challenge in Nile tilapia, Oreochromis niloticus

    Science.gov (United States)

    Microwave irradiation, as opposed to formalin exposure, has not routinely been used in the preparation of killed vaccines despite the advantages of decreased chemical toxicity, ability to kill cells quickly, ease of completion requiring only a standard microwave, and potential increased protein cons...

  3. 10 Gb/s operation of photonic crystal silicon optical modulators.

    Science.gov (United States)

    Nguyen, Hong C; Sakai, Yuya; Shinkawa, Mizuki; Ishikura, Norihiro; Baba, Toshihiko

    2011-07-04

    We report the first experimental demonstration of 10 Gb/s modulation in a photonic crystal silicon optical modulator. The device consists of a 200 μm-long SiO2-clad photonic crystal waveguide, with an embedded p-n junction, incorporated into an asymmetric Mach-Zehnder interferometer. The device is integrated on a SOI chip and fabricated by CMOS-compatible processes. With the bias voltage set at 0 V, we measure a V(π)L pseudo-random bit sequence signal. An open eye pattern is observed at bitrates of 10 Gb/s and 2 Gb/s, with and without pre-emphasis of the drive signal, respectively.

  4. A less invasive approach to screening for early onset neonatal GBS.

    LENUS (Irish Health Repository)

    Glackin, S

    2015-03-01

    Recent recommendations for the management of an asymptomatic term infant with one septic risk factor for Group B Streptococcal (GBS) invasive disease have advised a clinical approach. Following a previous audit in our unit which showed that high numbers of asymptomatic infants were receiving antibiotics, a new protocol was introduced which emphasised the importance of clinical examination. This study assessed the safety and efficacy of this new protocol through chart review of 1855 eligible infants. We found a statistically significant decrease (P < 0.0001) from 444 (19%) to 121 (6.5%) in the total number of term infants who underwent septic evaluations and received antibiotics. 241 asymptomatic infants with one septic risk factor were managed conservatively. No eligible infants had GBS invasive disease during the three month study period. The new protocol is a safe and effective tool for evaluating infants at risk of GBS invasive disease.

  5. Delineation of Streptococcus dysgalactiae, its subspecies, and its clinical and phylogenetic relationship to Streptococcus pyogenes

    DEFF Research Database (Denmark)

    Jensen, Anders; Kilian, Mogens

    2011-01-01

    The close phylogenetic relationship of the important pathogen Streptococcus pneumoniae and several species of commensal streptococci, particularly Streptococcus mitis and Streptococcus pseudopneumoniae, and the recently demonstrated sharing of genes and phenotypic traits previously considered...

  6. Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection

    OpenAIRE

    Hegde, Shivanand; Hegde, Shrilakshmi; Zimmermann, Martina; Flöck, Martina; Spergser, Joachim; Rosengarten, Renate; Chopra-Dewasthaly, Rohini

    2015-01-01

    Mycoplasmas possess complex pathogenicity determinants that are largely unknown at the molecular level. Mycoplasma agalactiae serves as a useful model to study the molecular basis of mycoplasma pathogenicity. The generation and in vivo screening of a transposon mutant library of M. agalactiae were employed to unravel its host colonization factors. Tn4001mod mutants were sequenced using a novel sequencing method, and functionally heterogeneous pools containing 15 to 19 selected mutants were sc...

  7. 40 Gb/s Pulse Generation Using Gain Switching of a Commercially Available Laser Module

    DEFF Research Database (Denmark)

    Nørregaard, Jesper; Hanberg, Jesper; Franck, Thorkild

    1999-01-01

    The laser module contains a single-mode, distributed feedback (DFB) laser diode. The epi-structure of the laser diode is grown by MOCVD as a multiple quantum well heterostructure. The DFB grating is defined by holography, and the laser diode is designed with a co-planar contact metallization...... time division multiplexing to generate a 40 Gb/s RZ pattern.The presentation will report on further details on the laser module including chirp characteristics, and show the eye diagrams taken at 10 and 40 Gb/s....

  8. 320-to-40-Gb/s optical demultiplexing using four-wave mixing in a quantum-dot soa

    NARCIS (Netherlands)

    Matsuura, M.; Gomez-Agis, F.; Calabretta, N.; Raz, O.; Dorren, H.J.S.

    2012-01-01

    We report, for the first time, the optical demultiplexing of a 320-Gb/s intensity-modulated signal using four-wave mixing in a quantum-dot semiconductor optical amplifier. Error-free operations were successfully achieved for all the 40-Gb/s channels extracted by the optical demultiplexer.

  9. Streptococcus suis infection

    Science.gov (United States)

    Feng, Youjun; Zhang, Huimin; Wu, Zuowei; Wang, Shihua; Cao, Min; Hu, Dan; Wang, Changjun

    2014-01-01

    Streptococcus suis (S. suis) is a family of pathogenic gram-positive bacterial strains that represents a primary health problem in the swine industry worldwide. S. suis is also an emerging zoonotic pathogen that causes severe human infections clinically featuring with varied diseases/syndromes (such as meningitis, septicemia, and arthritis). Over the past few decades, continued efforts have made significant progress toward better understanding this zoonotic infectious entity, contributing in part to the elucidation of the molecular mechanism underlying its high pathogenicity. This review is aimed at presenting an updated overview of this pathogen from the perspective of molecular epidemiology, clinical diagnosis and typing, virulence mechanism, and protective antigens contributing to its zoonosis. PMID:24667807

  10. Random Tagging Genotyping by Sequencing (rtGBS, an Unbiased Approach to Locate Restriction Enzyme Sites across the Target Genome.

    Directory of Open Access Journals (Sweden)

    Elena Hilario

    Full Text Available Genotyping by sequencing (GBS is a restriction enzyme based targeted approach developed to reduce the genome complexity and discover genetic markers when a priori sequence information is unavailable. Sufficient coverage at each locus is essential to distinguish heterozygous from homozygous sites accurately. The number of GBS samples able to be pooled in one sequencing lane is limited by the number of restriction sites present in the genome and the read depth required at each site per sample for accurate calling of single-nucleotide polymorphisms. Loci bias was observed using a slight modification of the Elshire et al.some restriction enzyme sites were represented in higher proportions while others were poorly represented or absent. This bias could be due to the quality of genomic DNA, the endonuclease and ligase reaction efficiency, the distance between restriction sites, the preferential amplification of small library restriction fragments, or bias towards cluster formation of small amplicons during the sequencing process. To overcome these issues, we have developed a GBS method based on randomly tagging genomic DNA (rtGBS. By randomly landing on the genome, we can, with less bias, find restriction sites that are far apart, and undetected by the standard GBS (stdGBS method. The study comprises two types of biological replicates: six different kiwifruit plants and two independent DNA extractions per plant; and three types of technical replicates: four samples of each DNA extraction, stdGBS vs. rtGBS methods, and two independent library amplifications, each sequenced in separate lanes. A statistically significant unbiased distribution of restriction fragment size by rtGBS showed that this method targeted 49% (39,145 of BamH I sites shared with the reference genome, compared to only 14% (11,513 by stdGBS.

  11. Field Trial of 40 Gb/s Optical Transport Network using Open WDM Interfaces

    DEFF Research Database (Denmark)

    Fagertun, Anna Manolova; Ruepp, Sarah Renée; Petersen, Martin Nordal

    2013-01-01

    An experimental field-trail deployment of a 40Gb/s open WDM interface in an operational network is presented, in cross-carrier interconnection scenario. Practical challenges of integration and performance measures for both native and alien channels are outlined....

  12. High-performance semiconductor optical preamplifier receiver at 10 Gb/s

    DEFF Research Database (Denmark)

    Mikkelsen, Benny; Jørgensen, Carsten Gudmann; Jensen, N.

    1993-01-01

    A semiconductor optical preamplifier receiver for bitrates of 10 Gb/s is described. The measured sensitivity is -28 dBm, with a polarization sensitivity of less than 0.5 dB. Using the same transmitter and receiver configuration but with a 980-nm pumped fiber amplifier instead of the semiconductor...... amplifier, the sensitivity is -34 dBm...

  13. Error-free 320 Gb/s simultaneous add-drop multiplexing

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Oxenløwe, Leif Katsuo; Clausen, Anders

    2007-01-01

    We report on the first demonstration of error-free time-division add-drop multiplexing at 320 Gb/s. The add- and drop-operations are performed simultaneously in a non-linear optical loop mirror with only 100 m of highly non-linear fibre....

  14. 8x40 Gb/s RZ all-optical broadcasting utilizing an electroabsorption modulator

    DEFF Research Database (Denmark)

    Xu, Lin; Chi, Nan; Yvind, Kresten

    2004-01-01

    We experimentally demonstrate all-optical broadcasting through simultaneous 8 × 40 Gb/s wavelength conversion in the RZ format based on cross absorption modulation in an electroabsorption modulator. The original intensity-modulated information is successfully duplicated onto eight wavelengths...

  15. Field trial of 160 Gb/s all-optical packet switching

    NARCIS (Netherlands)

    Liu, Y.; Herrera Llorente, J.; Raz, O.; Tangdiongga, E.; Marti, J.; Ramos, F.; Maxwell, G.D.; Poustie, A.; Mulvad, H.C.H.; Hill, M.T.; Waardt, de H.; Khoe, G.D.; Koonen, A.M.J.; Dorren, H.J.S.; Nakano, Y.

    2007-01-01

    We present the results of a transmission experiment, over 110 km of field installed fiber, for an all-optical 160 Gb/s packet switching system. The system uses in-band optical labels which are processed entirely in the optical domain using a narrow-band all-optical filter. The label decision

  16. 40-Gb/s all-optical processing systems using hybrid photonic integration technology

    NARCIS (Netherlands)

    Kehayas, E.; Tsiokos, D.; Bakapoulos, P.; Apostolopoulos, D.; Petrantonakis, D.; Stampoulidis, L.; Poustie, A.; McDougall, R.; Maxwell, G.D.; Liu, Y.; Zhang, S.; Dorren, H.J.S.; Seoane, J.; Van Holm-Nielsen, P.; Jeppesen, P.; Avramopoulos, H.

    2006-01-01

    This paper presents an experimental performance characterization of all-optical subsystems at 40 Gb/s using interconnected hybrid integrated all-optical semiconductor optical amplifier (SOA) Mach-Zehnder interferometer (MZI) gates and flip-flop prototypes. It was shown that optical gates can be

  17. 10 Gb/s Real-Time All-VCSEL Low Complexity Coherent scheme for PONs

    DEFF Research Database (Denmark)

    Rodes Lopez, Roberto; Cheng, Ning; Jensen, Jesper Bevensee

    2012-01-01

    Real time demodulation of a 10 Gb/s all-VCSEL based coherent PON link with a simplified coherent receiver scheme is demonstrated. Receiver sensitivity of −33 dBm is achieved providing high splitting ratio and link reach....

  18. 320 Gb/s Nyquist OTDM received by polarization-insensitive time-domain OFT

    DEFF Research Database (Denmark)

    Hu, Hao; Kong, Deming; Palushani, Evarist

    2014-01-01

    We have demonstrated the generation of a 320 Gb/s Nyquist-OTDM signal by rectangular filtering on an RZ-OTDM signal with the filter bandwidth (320 GHz) equal to the baud rate (320 Gbaud) and the reception of such a Nyquist-OTDM signal using polarization-insensitive time-domain optical Fourier tra...

  19. Evaluating imputation algorithms for low-depth genotyping-by-sequencing (GBS) data

    Science.gov (United States)

    Well-powered genomic studies require genome-wide marker coverage across many individuals. For non-model species with few genomic resources, high-throughput sequencing (HTS) methods, such as Genotyping-By-Sequencing (GBS), offer an inexpensive alternative to array-based genotyping. Although affordabl...

  20. Classification and characterization of species within the genus lens using genotyping-by-sequencing (GBS.

    Directory of Open Access Journals (Sweden)

    Melissa M L Wong

    Full Text Available Lentil (Lens culinaris ssp. culinaris is a nutritious and affordable pulse with an ancient crop domestication history. The genus Lens consists of seven taxa, however, there are many discrepancies in the taxon and gene pool classification of lentil and its wild relatives. Due to the narrow genetic basis of cultivated lentil, there is a need towards better understanding of the relationships amongst wild germplasm to assist introgression of favourable genes into lentil breeding programs. Genotyping-by-sequencing (GBS is an easy and affordable method that allows multiplexing of up to 384 samples or more per library to generate genome-wide single nucleotide Polymorphism (SNP markers. In this study, we aimed to characterize our lentil germplasm collection using a two-enzyme GBS approach. We constructed two 96-plex GBS libraries with a total of 60 accessions where some accessions had several samples and each sample was sequenced in two technical replicates. We developed an automated GBS pipeline and detected a total of 266,356 genome-wide SNPs. After filtering low quality and redundant SNPs based on haplotype information, we constructed a maximum-likelihood tree using 5,389 SNPs. The phylogenetic tree grouped the germplasm collection into their respective taxa with strong support. Based on phylogenetic tree and STRUCTURE analysis, we identified four gene pools, namely L. culinaris/L. orientalis/L. tomentosus, L. lamottei/L. odemensis, L. ervoides and L. nigricans which form primary, secondary, tertiary and quaternary gene pools, respectively. We discovered sequencing bias problems likely due to DNA quality and observed severe run-to-run variation in the wild lentils. We examined the authenticity of the germplasm collection and identified 17% misclassified samples. Our study demonstrated that GBS is a promising and affordable tool for screening by plant breeders interested in crop wild relatives.

  1. Development and host compatibility of plasmids for two important ruminant pathogens, Mycoplasma bovis and Mycoplasma agalactiae.

    Directory of Open Access Journals (Sweden)

    Shukriti Sharma

    Full Text Available Mycoplasma bovis is a cause of pneumonia, mastitis, arthritis and otitis media in cattle throughout the world. However, despite its clinical significance, there is a paucity of tools to genetically manipulate it, impeding our capacity to further explore the molecular basis of its virulence. To address this limitation, we developed a series of homologous and heterologous replicable plasmids from M. bovis and M. agalactiae. The shortest replicable oriC plasmid based on the region downstream of dnaA in M. bovis was 247 bp and contained two DnaA boxes, while oriC plasmids based on the region downstream of dnaA in M. agalactiae strains 5632 and PG2 were 219 bp and 217 bp in length, respectively, and contained only a single DnaA box. The efficiency of transformation in M. bovis and M. agalactiae was inversely correlated with the size of the oriC region in the construct, and, in general, homologous oriC plasmids had a higher transformation efficiency than heterologous oriC plasmids. The larger pWholeoriC45 and pMM21-7 plasmids integrated into the genomic oriC region of M. bovis, while the smaller oriC plasmids remained extrachromosomal for up to 20 serial passages in selective media. Although specific gene disruptions were not be achieved in M. bovis in this study, the oriC plasmids developed here could still be useful as tools in complementation studies and for expression of exogenous genes in both M. bovis and M. agalactiae.

  2. Development and Host Compatibility of Plasmids for Two Important Ruminant Pathogens, Mycoplasma bovis and Mycoplasma agalactiae

    Science.gov (United States)

    Sharma, Shukriti; Citti, Chistine; Sagné, Eveline; Marenda, Marc S.

    2015-01-01

    Mycoplasma bovis is a cause of pneumonia, mastitis, arthritis and otitis media in cattle throughout the world. However, despite its clinical significance, there is a paucity of tools to genetically manipulate it, impeding our capacity to further explore the molecular basis of its virulence. To address this limitation, we developed a series of homologous and heterologous replicable plasmids from M. bovis and M. agalactiae. The shortest replicable oriC plasmid based on the region downstream of dnaA in M. bovis was 247 bp and contained two DnaA boxes, while oriC plasmids based on the region downstream of dnaA in M. agalactiae strains 5632 and PG2 were 219 bp and 217 bp in length, respectively, and contained only a single DnaA box. The efficiency of transformation in M. bovis and M. agalactiae was inversely correlated with the size of the oriC region in the construct, and, in general, homologous oriC plasmids had a higher transformation efficiency than heterologous oriC plasmids. The larger pWholeoriC45 and pMM21-7 plasmids integrated into the genomic oriC region of M. bovis, while the smaller oriC plasmids remained extrachromosomal for up to 20 serial passages in selective media. Although specific gene disruptions were not be achieved in M. bovis in this study, the oriC plasmids developed here could still be useful as tools in complementation studies and for expression of exogenous genes in both M. bovis and M. agalactiae. PMID:25746296

  3. Experimental infections with Mycoplasma agalactiae identify key factors involved in host-colonization.

    Directory of Open Access Journals (Sweden)

    Eric Baranowski

    Full Text Available Mechanisms underlying pathogenic processes in mycoplasma infections are poorly understood, mainly because of limited sequence similarities with classical, bacterial virulence factors. Recently, large-scale transposon mutagenesis in the ruminant pathogen Mycoplasma agalactiae identified the NIF locus, including nifS and nifU, as essential for mycoplasma growth in cell culture, while dispensable in axenic media. To evaluate the importance of this locus in vivo, the infectivity of two knock-out mutants was tested upon experimental infection in the natural host. In this model, the parental PG2 strain was able to establish a systemic infection in lactating ewes, colonizing various body sites such as lymph nodes and the mammary gland, even when inoculated at low doses. In these PG2-infected ewes, we observed over the course of infection (i the development of a specific antibody response and (ii dynamic changes in expression of M. agalactiae surface variable proteins (Vpma, with multiple Vpma profiles co-existing in the same animal. In contrast and despite a sensitive model, none of the knock-out mutants were able to survive and colonize the host. The extreme avirulent phenotype of the two mutants was further supported by the absence of an IgG response in inoculated animals. The exact role of the NIF locus remains to be elucidated but these data demonstrate that it plays a key role in the infectious process of M. agalactiae and most likely of other pathogenic mycoplasma species as many carry closely related homologs.

  4. Mycoplasma agalactiae in semen and milk of goat from Pernambuco state, Brazil

    Directory of Open Access Journals (Sweden)

    Bruno H.L.S. Alves

    2013-11-01

    Full Text Available In goat and sheep flocks, mycoplasmosis is a disease that may cause severe economical losses associated with polyarthritis, mastitis, agalactia, conjunctivitis, pneumonia and reproductive failure. The latter may involve repeat breeding, granular vulvovaginitis, infertility and abortions. The aim of the present study was to assess the occurrence of Mycoplasma agalactiae (Ma in semen and milk samples from naturally infected goat in the semiarid region from Pernambuco State, Northeast from Brazil. Thirty-nine semen samples and 81 milk samples were submitted to DNA extraction using a commercially available kit and following the manufacturer's instructions. The polymerase chain reaction (PCR was then performed in accordance with protocols described in the literature. The results of the present study revealed the presence of Ma in the DNA of 17.9% (7/39 of the semen samples and 3.7% (3/81 of the milk samples. The results obtained in the present study confirm the elimination of the DNA of Ma in the semen and milk samples. The presence of this agent in goat flocks is considered very risky in terms of reproductive disorders and contagious agalactia outbreaks in the Northeast region of Brazil.

  5. A Highly Arginolytic Streptococcus Species That Potently Antagonizes Streptococcus mutans.

    Science.gov (United States)

    Huang, Xuelian; Palmer, Sara R; Ahn, Sang-Joon; Richards, Vincent P; Williams, Matthew L; Nascimento, Marcelle M; Burne, Robert A

    2016-01-29

    The ability of certain oral biofilm bacteria to moderate pH through arginine metabolism by the arginine deiminase system (ADS) is a deterrent to the development of dental caries. Here, we characterize a novel Streptococcus strain, designated strain A12, isolated from supragingival dental plaque of a caries-free individual. A12 not only expressed the ADS pathway at high levels under a variety of conditions but also effectively inhibited growth and two intercellular signaling pathways of the dental caries pathogen Streptococcus mutans. A12 produced copious amounts of H2O2 via the pyruvate oxidase enzyme that were sufficient to arrest the growth of S. mutans. A12 also produced a protease similar to challisin (Sgc) of Streptococcus gordonii that was able to block the competence-stimulating peptide (CSP)-ComDE signaling system, which is essential for bacteriocin production by S. mutans. Wild-type A12, but not an sgc mutant derivative, could protect the sensitive indicator strain Streptococcus sanguinis SK150 from killing by the bacteriocins of S. mutans. A12, but not S. gordonii, could also block the XIP (comX-inducing peptide) signaling pathway, which is the proximal regulator of genetic competence in S. mutans, but Sgc was not required for this activity. The complete genome sequence of A12 was determined, and phylogenomic analyses compared A12 to streptococcal reference genomes. A12 was most similar to Streptococcus australis and Streptococcus parasanguinis but sufficiently different that it may represent a new species. A12-like organisms may play crucial roles in the promotion of stable, health-associated oral biofilm communities by moderating plaque pH and interfering with the growth and virulence of caries pathogens. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  6. Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection.

    Science.gov (United States)

    Hegde, Shivanand; Hegde, Shrilakshmi; Zimmermann, Martina; Flöck, Martina; Spergser, Joachim; Rosengarten, Renate; Chopra-Dewasthaly, Rohini

    2015-07-01

    Mycoplasmas possess complex pathogenicity determinants that are largely unknown at the molecular level. Mycoplasma agalactiae serves as a useful model to study the molecular basis of mycoplasma pathogenicity. The generation and in vivo screening of a transposon mutant library of M. agalactiae were employed to unravel its host colonization factors. Tn4001mod mutants were sequenced using a novel sequencing method, and functionally heterogeneous pools containing 15 to 19 selected mutants were screened simultaneously through two successive cycles of sheep intramammary infections. A PCR-based negative selection method was employed to identify mutants that failed to colonize the udders and draining lymph nodes in the animals. A total of 14 different mutants found to be absent from ≥ 95% of samples were identified and subsequently verified via a second round of stringent confirmatory screening where 100% absence was considered attenuation. Using this criterion, seven mutants with insertions in genes MAG1050, MAG2540, MAG3390, uhpT, eutD, adhT, and MAG4460 were not recovered from any of the infected animals. Among the attenuated mutants, many contain disruptions in hypothetical genes, implying their previously unknown role in M. agalactiae pathogenicity. These data indicate the putative role of functionally different genes, including hypothetical ones, in the pathogenesis of M. agalactiae. Defining the precise functions of the identified genes is anticipated to increase our understanding of M. agalactiae infections and to develop successful intervention strategies against it. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. Is Penicillin plus Gentamicin Synergistic against Clinical Group B Streptococcus isolates?: A in-vitro Study.

    Directory of Open Access Journals (Sweden)

    Corinne Ruppen

    2016-10-01

    Full Text Available Group B Streptococcus (GBS is increasingly causing invasive infections in nonpregnant adults. Elderly patients and those with comorbidities are at increased risk. On the basis of previous studies focusing on neonatal infections, penicillin plus gentamicin is recommended for infective endocarditis (IE and periprosthetic joint infections (PJI in adults. The purpose of this study was to investigate whether a synergism with penicillin and gentamicin is present in GBS isolates that caused IE and PJI. We used 5 GBS isolates, two clinical strains and three control strains, including one displaying high-level gentamicin resistance (HLGR. The results from the checkerboard and time-kill assays (TKAs were compared. For TKAs, antibiotic concentrations for penicillin were 0.048 and 0.2 mg/L, and for gentamicin 4 mg/L or 12.5 mg/L. In the checkerboard assay, the median fractional inhibitory concentration indices (FICIs of all isolates indicated indifference. TKAs for all isolates failed to demonstrate synergism with penicillin 0.048 or 0.2 mg/L, irrespective of gentamicin concentrations used. Rapid killing was seen with penicillin 0.048 mg/L plus either 4 mg/L or 12.5 mg/L gentamicin, from 2 h up to 8 h hours after antibiotic exposure. TKAs with penicillin 0.2 mg/L decreased the starting inoculum below the limit of quantification within 4 h to 6 h, irrespective of the addition of gentamicin. Fast killing was seen with penicillin 0.2 mg/L plus 12.5 mg/L gentamicin within the first 2 h. Our in vitro results indicate that the addition of gentamicin to penicillin contributes to faster killing at low penicillin concentrations, but only within the first few hours. Twenty-four hours after antibiotic exposure, PEN alone was bactericidal and synergism was not seen.

  8. Design and OAM&P aspects of a DWDM system equipped with a 40Gb/s PM-QPSK alien wavelength and adjacent 10Gb/s channels

    DEFF Research Database (Denmark)

    Nuijts, Roeland; Bjørn, Lars Lange; Petersen, Martin Nordal

    2011-01-01

    We present theoretical and experimental investigations of the interaction, in terms of BER performance, between a 40Gb/s PM-QPSK alien wavelength and adjacent (50GHz spacing) 10Gb/s NRZ-OOK channels. Experiments were conducted on the Hamburg-Copenhagen section of the Amsterdam-Copenhagen CBF (Cross...... Border Fiber) connection between SURFnet and NORDUnet. Furthermore, we investigated the OAM&P (Operation, Administration, Maintenance and Provisioning) of an alien wavelength in CBF transmission systems....

  9. Fabrication of 32Gb/s Electroabsorption Modulated Distributed Feedback Lasers by Selective Area Growth Technology

    International Nuclear Information System (INIS)

    Zhou Dai-Bing; Wang Hui-Tao; Zhang Rui-Kang; Wang Bao-Jun; Bian Jing; An Xin; Lu Dan; Zhao Ling-Juan; Zhu Hong-Liang; Ji Chen; Wang Wei

    2015-01-01

    A 32 Gb/s monolithically integrated electroabsorption modulated laser is fabricated by selective area growth technology. The threshold current of the device is below 13 mA. The output power exceeds 10 mW at 0 V bias when the injection current of the distributed feedback laser is 100 mA at 25°C. The side mode suppression ratio is over 50 dB. A 32Gb/s eye diagram is measured with a 3.5V pp nonreturn-to-zero pseudorandom modulation signal at −2.3 V bias. A clearly opening eyediagram with a dynamic extinction ratio of 8.01 dB is obtained. (paper)

  10. Demonstration of an 8 × 25-Gb/s optical time-division multiplexing system

    Science.gov (United States)

    Wang, Dong; Huo, Li; Li, Yunbo; Wang, Lei; Li, Han; Jiang, Xiangyu; Chen, Xin; Lou, Caiyun

    2017-11-01

    An 8 × 25-Gb/s optical time-division multiplexing (OTDM) system is demonstrated experimentally. The optical pulse source is based on optical frequency comb (OFC) generation and pulse shaping, which can generate nearly chirp-free 25-GHz 1.6-ps optical Gaussian pulse. The eightfold optical time-division demultiplexer consists of a single-driven dual-parallel Mach-Zehnder modulator (DPMZM) and a Mamyshev reshaper. Error-free demultiplexing of 8 × 25-Gb/s back-to-back (B2B) signal with a power penalty of 4.1 dB to 4.4 dB at a bit error rate (BER) of 10-9 is achieved to confirm the performance of the proposed system.

  11. A robust, simple genotyping-by-sequencing (GBS approach for high diversity species.

    Directory of Open Access Journals (Sweden)

    Robert J Elshire

    Full Text Available Advances in next generation technologies have driven the costs of DNA sequencing down to the point that genotyping-by-sequencing (GBS is now feasible for high diversity, large genome species. Here, we report a procedure for constructing GBS libraries based on reducing genome complexity with restriction enzymes (REs. This approach is simple, quick, extremely specific, highly reproducible, and may reach important regions of the genome that are inaccessible to sequence capture approaches. By using methylation-sensitive REs, repetitive regions of genomes can be avoided and lower copy regions targeted with two to three fold higher efficiency. This tremendously simplifies computationally challenging alignment problems in species with high levels of genetic diversity. The GBS procedure is demonstrated with maize (IBM and barley (Oregon Wolfe Barley recombinant inbred populations where roughly 200,000 and 25,000 sequence tags were mapped, respectively. An advantage in species like barley that lack a complete genome sequence is that a reference map need only be developed around the restriction sites, and this can be done in the process of sample genotyping. In such cases, the consensus of the read clusters across the sequence tagged sites becomes the reference. Alternatively, for kinship analyses in the absence of a reference genome, the sequence tags can simply be treated as dominant markers. Future application of GBS to breeding, conservation, and global species and population surveys may allow plant breeders to conduct genomic selection on a novel germplasm or species without first having to develop any prior molecular tools, or conservation biologists to determine population structure without prior knowledge of the genome or diversity in the species.

  12. 160 Gb/s OFDM transmission utilizing an all-optical symbol generator based on PLC

    Science.gov (United States)

    Liang, Xiaojun; Qiao, Yaojun; Li, Wei; Mei, Junyao; Qin, Yi

    2009-11-01

    We demonstrate a 160 Gb/s orthogonal frequency division multiplexing (OFDM) system using an all-optical symbol generator based on planar light circuit (PLC) technology. Excellent bit error rate (BER) is observed after long-distance transmission. The proposed symbol generator fundamentally eliminates the processing speed limits introduced by electronics and is suitable for high integration, making it physically realizable to build high-speed all-optical OFDM systems with a large number of subcarriers.

  13. Modeling novel back-pressure mechanisms for a 100 Gb/s switch

    DEFF Research Database (Denmark)

    Fagertun, Anna Manolova; Ruepp, Sarah Renée

    2012-01-01

    In this work we evaluate the performance of novel back-pressure mechanisms in a Clos-based 100 Gb/s switch system via OPNET modeler simulations. The effectiveness of the mechanisms under different switch configurations, as well as under different traffic patterns, is presented. Our results indicate...... that the proposed back-pressure techniques can effectively reduce the requirements for buffer space in the different stages of the Clos switch....

  14. Experimental Investigation of Digital Compensation of DGD for 112 Gb/s PDM-QPSK Clock Recovery

    DEFF Research Database (Denmark)

    Zibar, Darko; de Oliviera, Julio Cesar R.; Ribeiro, Vitor B.

    2011-01-01

    For the first time, the impact of DGD on clock recovery for 112Gb/s PDM-QPSK is experimentally investigated and quantified. We propose and experimentally demonstrate novel digital adaptive timing error detector which is robust to DGD....

  15. A 10 Gb/s passive-components-based WDM-TDM reconfigurable optical access network architecture

    NARCIS (Netherlands)

    Tran, N.C.; Jung, H.D.; Okonkwo, C.M.; Tangdiongga, E.; Koonen, A.M.J.

    2011-01-01

    We propose a cost-effective, reconfigurable optical access network by employing passive components in the remote node and dual conventional optical transceivers in ONUs. The architecture is demonstrated with bidirectional transmission at 10 Gb/s.

  16. Up to 40 Gb/s wireless signal generation and demodulation in 75-110 GHz band using photonic techniques

    DEFF Research Database (Denmark)

    Sambaraju, R.; Zibar, Darko; Caballero Jambrina, Antonio

    2010-01-01

    Record wireless signal capacity of up to 40 Gb/s is demonstrated in the 75-110 GHz band. All-optical OFDM and photonic up-conversion are used for generation and digital coherent detection for demodulation....

  17. 2.5 Gb/s laser-driver GaAS IC

    DEFF Research Database (Denmark)

    Riishøj, Jesper

    1993-01-01

    A laser-diode driver GaAs IC incorporating an optional NRZ/RZ (non-return-to-zero/return-to-zero) conversion facility, having ECL (emitter-coupled logic) and SCFL (source-coupled FET logic)-compatible inputs and providing a 0-60-mA adjustable output current into a 50-Ω/5-V termination at bit rates...... obtained. To verify laser driving performance a back-to-back optical-fiber transmission experiment was performed, giving good optical eye diagrams at 2.5 Gb/s. The electrooptical interplay between laser-diode driver and laser-diode has been demonstrated using SPICE simulations...... up to 2 Gb/s NRZ and maintaining a clear eye opening of 50 mA at 2.5 Gb/s NRZ bit rate has been designed, using a commercial 1-μm gate-length (Fτ=12 GHz) GaAs MESFET foundry service. The high maximum output current is obtained by implementing the output driver as a cascode differential amplifier...

  18. Architectural Design Study for a 10Gb/s Ethernet Switch

    CERN Document Server

    Oltean, Alexandra Dana

    2004-01-01

    The demand for 10Gb/s switches at this early stage in the market is primarily for modular solutions that can grow as do the bandwidth requirements. This indicates a requirement for chassis based solutions where individual line cards can be added to a chassis infrastructure and have to communicate across a 10Gb/s switching backplane. The present study is provides an architectural design solution for a passive copper backplane used for moving data between the line cards of a 10Gb/s Ethernet switch system. The ability to pass multi-gigabit data rates through a backplane system requires great attention to details previously thought to be irrelevant at lower frequencies. The trace dimensions, the via holes diameters, the backplane materials and choice of connectors, all play a crucial role in determining the success of the system. At high-speed even a subtle change in any of these elements can drastically affect the end-to-end system performance. In this context, the study presents the modeling and simulation work...

  19. Receiver Architecture for 12.5 Gb/s 16-ary Pulse Position Modulation (PPM) Signaling

    Energy Technology Data Exchange (ETDEWEB)

    Mendez, A J; Gagliardi, R M; Hernandez, V J; Bennett, C V

    2008-07-11

    PPM is a signaling scheme that enables the transmission of multiple bits per symbol [1]. It has found favor in the regime of free space optical communications ('FSO' or 'Lasercom'); however, PPM has yet to be widely applied to fiber optic-based communications. Its limitation in fiber results from the exceedingly high bandwidth requirements needed to electronically process a directly detected pulse, especially as the symbol rate increases and the pulse width correspondingly decreases. As a solution, we introduced the concept of a virtual quadrant receiver for receiving 1.25 Gb/s 4-ary PPM, where photonic processing reduced the number of required electronic components [2]. In this paper, we extend these photonic process techniques to a 16-ary, 12.5 Gb/s (10 Gb/s plus 8B/10B line coding) PPM communications system for fiber optic avionics, wherein much of the receiver processing is enabled by techniques based on planar lightwave circuits (PLCs). The architecture is applicable to higher input data rates and M-ary PPM. In the following, we present the PPM encoding and decoding architectures and numerically simulated results.

  20. End-System Network Interface Controller for 100 Gb/s Wide Area Networks: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Jesse [Acadia Optronics LLC, Rockville, MD (United States)

    2013-08-30

    In recent years, network bandwidth requirements have scaled multiple folds, pushing the need for the development of data exchange mechanisms at 100 Gb/s and beyond. High performance computing, climate modeling, large-scale storage, and collaborative scientific research are examples of applications that can greatly benefit by leveraging high bandwidth capabilities of the order of 100 Gb/s. Such requirements and advances in IEEE Ethernet standards, Optical Transport Unit4 (OTU4), and host-system interconnects demand a network infrastructure supporting throughput rates of the order of 100 Gb/s with a single wavelength. To address such a demand Acadia Optronics in collaboration with the University of New Mexico, proposed and developed a end-system Network Interface Controller (NIC) for the 100Gbps WANs. Acadia’s 100G NIC employs an FPGA based system with a high-performance processor interconnect (PCIe 3.0) and a high capacity optical transmission link (CXP) to provide data transmission at the rate of 100 Gbps.

  1. Generating a Square Switching Window for Timing Jitter Tolerant 160 Gb/s Demultiplexing by the Optical Fourier Transform Technique

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Galili, Michael; Clausen, A. T:

    2006-01-01

    A square spectrum is optically Fourier transformed into a square pulse in the time domain. This is used to demultiplex a 160 Gb/s data signal with a significant increase in jitter tolerance to 2.6 ps.......A square spectrum is optically Fourier transformed into a square pulse in the time domain. This is used to demultiplex a 160 Gb/s data signal with a significant increase in jitter tolerance to 2.6 ps....

  2. 40 Gb/s Lane Rate NG-PON using Electrical/Optical Duobinary, PAM-4 and Low Complex Equalizations

    DEFF Research Database (Denmark)

    Wei, J. L.; Grobe, Klaus; Wagner, Christoph

    2016-01-01

    We present the first numerical investigation and comparison of 40-Gb/s lane rate electrical Duobinary, optical Duobinary and PAM-4 for NG-PONs incorporating low complex linear and nonlinear post-equalizations.......We present the first numerical investigation and comparison of 40-Gb/s lane rate electrical Duobinary, optical Duobinary and PAM-4 for NG-PONs incorporating low complex linear and nonlinear post-equalizations....

  3. Recombination-deficient Streptococcus sanguis

    International Nuclear Information System (INIS)

    Daneo-Moore, L.; Volpe, A.

    1985-01-01

    A UV-sensitive derivative was obtained from Streptococcus sanguis Challis. The organism could be transformed with a number of small streptococcal plasmids at frequencies equal to, or 1 logarithm below, the transformation frequencies for the parent organism. However, transformation with chromosomal DNA was greatly impaired in the UV-sensitive derivative

  4. Salivary agglutinin, which binds Streptococcus mutans and Helicobacter pylori, is the lung scavenger receptor cysteine-rich protein gp-340.

    Science.gov (United States)

    Prakobphol, A; Xu, F; Hoang, V M; Larsson, T; Bergstrom, J; Johansson, I; Frängsmyr, L; Holmskov, U; Leffler, H; Nilsson, C; Borén, T; Wright, J R; Strömberg, N; Fisher, S J

    2000-12-22

    Salivary agglutinin is a high molecular mass component of human saliva that binds Streptococcus mutans, an oral bacterium implicated in dental caries. To study its protein sequence, we isolated the agglutinin from human parotid saliva. After trypsin digestion, a portion was analyzed by matrix-assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), which gave the molecular mass of 14 unique peptides. The remainder of the digest was subjected to high performance liquid chromatography, and the separated peptides were analyzed by MALDI-TOF/post-source decay; the spectra gave the sequences of five peptides. The molecular mass and peptide sequence information showed that salivary agglutinin peptides were identical to sequences in lung (lavage) gp-340, a member of the scavenger receptor cysteine-rich protein family. Immunoblotting with antibodies that specifically recognized either lung gp-340 or the agglutinin confirmed that the salivary agglutinin was gp-340. Immunoblotting with an antibody specific to the sialyl Le(x) carbohydrate epitope detected expression on the salivary but not the lung glycoprotein, possible evidence of different glycoforms. The salivary agglutinin also interacted with Helicobacter pylori, implicated in gastritis and peptic ulcer disease, Streptococcus agalactiae, implicated in neonatal meningitis, and several oral commensal streptococci. These results identify the salivary agglutinin as gp-340 and suggest it binds bacteria that are important determinants of either the oral ecology or systemic diseases.

  5. Streptococcus pneumoniae Drugs Resistance in Acute Rhinosinusitis

    Directory of Open Access Journals (Sweden)

    Chong Jie Hao

    2016-03-01

    Full Text Available Background: Acute rhinosinusitis that usually caused by Streptococcus pneumoniae becomes the reason why patients seek for medical care. Drugs resistance in Streptococcus pneumoniae is increasing worldwide. This study was conducted to determine drugs resistance of Streptococcus pneumonia from acute rhinosinusitis in Dr. Hasan Sadikin General Hospital. Methods: A descriptive laboratory study was conducted in June–October 2014 at the Laboratory of Microbiology Faculty of Medicine Universitas Padjadjaran. The sample was taken using nasopharyngeal swabbing from 100 acute rhinosinusitis patients in Dr. Hasan Sadikin General Hospital and planted on tryptic soy agar containing 5% sheep blood and 5 μg/ml of gentamicin sulphate and then incubated in 5% CO2 incubator at 37°C for 24 hours. The identification of Streptococcus pneumonia was performed by optochin test. The susceptibility test against Streptococcus pneumoniae was done using disk diffusion method.The antibiotic disks were trimethoprim-sulfamethoxazole, oxacillin, levofloxacin, azithromycin, and doxycycline. Results: Out of 100 samples, 8 of them were tested positive for Streptococcus pneumoniae. Three of Streptococcus pneumoniae isolates died with unknown reason after it were stored at -80 .The drugs resistance test showed the resistance of Streptococcus pneumonia to oxacillin, azithromycin and trimethoprim were 6, whereas levofloxacin and doxycycline are 4. Conclusions: Streptococcus pneumonia drugs resistance in acute rhinosinusitis shows the resistance of Streptococcus pneumoniae to oxacillin, azithromycin and trimethoprim are 6, whereas the resistance to levofloxacin and doxycycline are 4.

  6. Pretreatment with Pancaspase Inhibitor (Z-VAD-FMK Delays but Does Not Prevent Intraperitoneal Heat-Killed Group B Streptococcus-Induced Preterm Delivery in a Pregnant Mouse Model

    Directory of Open Access Journals (Sweden)

    Ozlem Equils

    2009-01-01

    Full Text Available Caspases and apoptosis are thought to play a role in infection-associated preterm-delivery. We have shown that in vitro treatment with pancaspase inhibitor Z-VAD-FMK protects trophoblasts from microbial antigen-induced apoptosis. Objective. To examine whether in vivo administration of Z-VAD-FMK would prevent infection-induced preterm-delivery. Methods. We injected 14.5 day-pregnant-mice with heat-killed group B streptococcus (HK-GBS. Apoptosis within placentas and membranes was assessed by TUNEL staining. Calpain expression and caspase-3 activation were assessed by immunohistochemistry. Preterm-delivery was defined as expulsion of a fetus within 48 hours after injection. Results. Intrauterine (i.u. or intraperitoneal (i.p. HK-GBS injection led to preterm-delivery and induced apoptosis in placentas and membranes at 14 hours. The expression of calpain, a caspase-independent inducer of apoptosis, was increased in placenta. Treatment with the specific caspase inhibitor Z-VAD-FMK (i.p. prior to HK-GBS (i.p. delayed but did not prevent preterm-delivery. Conclusion. Caspase-dependent apoptosis appears to play a role in the timing but not the occurrence of GBS-induced preterm delivery in the mouse.

  7. Adhesion of streptococcus rattus and streptococcus mutans to metal surfaces

    International Nuclear Information System (INIS)

    Branting, C.; Linder, L.E.; Sund, M.-L.; Oden, A.; Wiatr-Adamczak, E.

    1988-01-01

    The adhesion of Streptococcus rattus BHT and Streptococcus mutans IB to metal specimens of amalgam, silver, tin and copper was studied using (6- 3 H) thymidine labeled cells. In the standard assay the metal specimens were suspended by a nylon thread in an adhesion solution containing a chemically defined bacterial growth medium (FMC), sucrose, and radiolabeled bacteria. Maximum amounts of adhering bacteria were obtained after about 100 min of incubation. Saturation of the metal specimens with bacteria was not observed. Both strains also adhered in the absence of sucrose, indicating that glucan formation was not necessary for adhesion. However, in the presence of glucose, adhesion was only 26-45% of that observed in the presence of equimolar sucrose. Sucrose-dependent stimulation of adhesion seemed to be due to increased cell-to-cell adhesion capacity. Isolated radiolabeled water-insoluble and water-soluble polysaccharides produced from sucrose by S. rattus BHT were not adsorbed to the metal surfaces. (author)

  8. Adhesion of streptococcus rattus and streptococcus mutans to metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Branting, C.; Linder, L.E.; Sund, M.-L.; Oden, A.; Wiatr-Adamczak, E.

    1988-01-01

    The adhesion of Streptococcus rattus BHT and Streptococcus mutans IB to metal specimens of amalgam, silver, tin and copper was studied using (6-/sup 3/H) thymidine labeled cells. In the standard assay the metal specimens were suspended by a nylon thread in an adhesion solution containing a chemically defined bacterial growth medium (FMC), sucrose, and radiolabeled bacteria. Maximum amounts of adhering bacteria were obtained after about 100 min of incubation. Saturation of the metal specimens with bacteria was not observed. Both strains also adhered in the absence of sucrose, indicating that glucan formation was not necessary for adhesion. However, in the presence of glucose, adhesion was only 26-45% of that observed in the presence of equimolar sucrose. Sucrose-dependent stimulation of adhesion seemed to be due to increased cell-to-cell adhesion capacity. Isolated radiolabeled water-insoluble and water-soluble polysaccharides produced from sucrose by S. rattus BHT were not adsorbed to the metal surfaces.

  9. Streptococcus oligofermentans inhibits Streptococcus mutans in biofilms at both neutral pH and cariogenic conditions

    NARCIS (Netherlands)

    Bao, X.; de Soet, J.J.; Tong, H.; Gao, X.; He, L.; van Loveren, C.; Deng, D.M.

    2015-01-01

    Homeostasis of oral microbiota can be maintained through microbial interactions. Previous studies showed that Streptococcus oligofermentans, a non-mutans streptococci frequently isolated from caries-free subjects, inhibited the cariogenic Streptococcus mutans by the production of hydrogen peroxide

  10. Antibiotic Susceptibility of Periodontal Streptococcus Constellatus and Streptococcus Intermedius Clinical Isolates

    NARCIS (Netherlands)

    Rams, Thomas E; Feik, Diane; Mortensen, Joel E; Degener, John E; van Winkelhoff, Arie J

    2014-01-01

    Background: Streptococcus constellatus and Streptococcus intermedius in subgingival dental plaque biofilms may contribute to forms of periodontitis that resist treatment with conventional mechanical root debridement/surgical procedures and may additionally participate in some extraoral infections.

  11. Comparaison de la souche 7784 hypovirulente de Mycoplasma agalactiae à la souche type virulente PG2 par la technique d'hybridation soustractive suppressive

    OpenAIRE

    Bonnefin, Nathalie

    2003-01-01

    Mycoplasma agalactiae est l'agent principal responsable de l'agalactie contagieuse des ovins et caprins, un syndrome largement répandu dans le monde et regroupant des atteintes mammaires, articulaires et oculaires. Afin de rechercher les bases moléculaires du pouvoir pathogène de M. agalactiae, la technique d'hybridation soustractive suppressive, qui permet l'identification de séquences présentes dans un génome mais absentes d'un autre, a été utilisée. Deux souches de M. agalactiae ont été co...

  12. Conceptual studies of construction and safety enhancement of ocean SMART mounted on GBS

    International Nuclear Information System (INIS)

    Kim, Min-Gil; Lee, Kang-Heon; Kim, Seong Gu; Woo, Il-Guk; Han, Jeong-Hoon; Lee, Phill-Seung; Lee, Jeong Ik

    2014-01-01

    Highlights: • We suggested the concept of coupling the SMART to the GBS, and we made suggested improvements. • We describe the design concepts and GA of SMART ONPP. • We analyzed seismic feature of SMART ONPP preliminarily. • We suggested the concept of coupling the IPSS to the SMART ONPP, and we made suggested improvements. - Abstract: From the Fukushima accident, protection of NPPs from any imaginable natural disasters became very important. In this study, the authors suggest a new concept of ocean nuclear power plant (ONPP) by using SMART as a reference reactor, which is the most recent Small Modular Reactor (SMR) developed by Korea, to demonstrate that the proposed concept can improve the safety of NPP from earthquake and tsunami. The proposed concept utilizes Gravity Based Structure (GBS), which is a widely spread construction technique of offshore plants. Because, floating type or submerged type NPPs can be easily affected by severe ocean environments such as tsunamis and storms, additional safety features have to be added to the existing land based plant. In contrast, the newly proposed GBS-type ONPP does not require going through significant design modifications due to inherent characteristics of the construction method. The authors have demonstrated this concept can be applied to the large nuclear power plant in the previous work and will expand this concept for SMRs in this paper. The authors discuss the new concept by presenting design parameters, design requirements, and the new total general arrangement. Furthermore, due to the unique configuration of ONPP SMART, innovative passive safety features can be added to the existing SMART design. The performance of proposed concept to resist earthquake as well as newly added passive safety feature will be discussed by presenting simplified analysis results

  13. Conceptual studies of construction and safety enhancement of ocean SMART mounted on GBS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Gil, E-mail: gggggtt@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, Kang-Heon, E-mail: welcome@kaist.ac.kr [Division of Ocean Systems Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Seong Gu, E-mail: skim07@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Woo, Il-Guk, E-mail: igwoo@dsme.co.kr [Department of Energy System R and D (Plant R and D), Daewoo Shipbuilding and Marine Engineering Co., Ltd., 221-17, Nonhyun-Dong, Gangnam-Gu, Seoul 135-010 (Korea, Republic of); Han, Jeong-Hoon, E-mail: jhhan1@dsme.co.kr [Department of Energy System R and D (Plant R and D), Daewoo Shipbuilding and Marine Engineering Co., Ltd., 221-17, Nonhyun-Dong, Gangnam-Gu, Seoul 135-010 (Korea, Republic of); Lee, Phill-Seung, E-mail: philseung@kaist.edu [Division of Ocean Systems Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Lee, Jeong Ik, E-mail: jeongiklee@kaist.ac.kr [Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2014-10-15

    Highlights: • We suggested the concept of coupling the SMART to the GBS, and we made suggested improvements. • We describe the design concepts and GA of SMART ONPP. • We analyzed seismic feature of SMART ONPP preliminarily. • We suggested the concept of coupling the IPSS to the SMART ONPP, and we made suggested improvements. - Abstract: From the Fukushima accident, protection of NPPs from any imaginable natural disasters became very important. In this study, the authors suggest a new concept of ocean nuclear power plant (ONPP) by using SMART as a reference reactor, which is the most recent Small Modular Reactor (SMR) developed by Korea, to demonstrate that the proposed concept can improve the safety of NPP from earthquake and tsunami. The proposed concept utilizes Gravity Based Structure (GBS), which is a widely spread construction technique of offshore plants. Because, floating type or submerged type NPPs can be easily affected by severe ocean environments such as tsunamis and storms, additional safety features have to be added to the existing land based plant. In contrast, the newly proposed GBS-type ONPP does not require going through significant design modifications due to inherent characteristics of the construction method. The authors have demonstrated this concept can be applied to the large nuclear power plant in the previous work and will expand this concept for SMRs in this paper. The authors discuss the new concept by presenting design parameters, design requirements, and the new total general arrangement. Furthermore, due to the unique configuration of ONPP SMART, innovative passive safety features can be added to the existing SMART design. The performance of proposed concept to resist earthquake as well as newly added passive safety feature will be discussed by presenting simplified analysis results.

  14. All-optical 10 Gb/s AND logic gate in a silicon microring resonator

    DEFF Research Database (Denmark)

    Xiong, Meng; Lei, Lei; Ding, Yunhong

    2013-01-01

    An all-optical AND logic gate in a single silicon microring resonator is experimentally demonstrated at 10 Gb/s with 50% RZ-OOK signals. By setting the wavelengths of two intensity-modulated input pumps on the resonances of the microring resonator, field-enhanced four-wave mixing with a total inp...... power of only 8.5 dBm takes place in the ring, resulting in the generation of an idler whose intensity follows the logic operation between the pumps. Clear and open eye diagrams with a bit-error- ratio below 10−9 are achieved....

  15. Cost-effectiveness of maternal GBS immunization in low-income sub-Saharan Africa.

    Science.gov (United States)

    Russell, Louise B; Kim, Sun-Young; Cosgriff, Ben; Pentakota, Sri Ram; Schrag, Stephanie J; Sobanjo-Ter Meulen, Ajoke; Verani, Jennifer R; Sinha, Anushua

    2017-12-14

    A maternal group B streptococcal (GBS) vaccine could prevent neonatal sepsis and meningitis. Its cost-effectiveness in low-income sub-Saharan Africa, a high burden region, is unknown. We used a decision tree model, with Markov nodes to project infants' lifetimes, to compare maternal immunization delivered through routine antenatal care with no immunization. 37 countries were clustered on the basis of economic and health resources and past public health performance. Vaccine efficacy for covered serotypes was ranged from 50% to 90%. The model projected EOGBS (early-onset) and LOGBS (late-onset) cases and deaths, disability-adjusted life years (DALYs), healthcare costs (2014 US$), and cost-effectiveness for a representative country in each of the four clusters: Guinea-Bissau, Uganda, Nigeria, and Ghana. Maximum vaccination costs/dose were estimated to meet two cost-effectiveness benchmarks, 0.5 GDP and GDP per capita/DALY, for ranges of disease incidence (reported and adjusted for under-reporting) and vaccine efficacy. At coverage equal to the proportion of pregnant women with≥4 antenatal visits (ANC4) and serotype-specific vaccine efficacy of 70%, maternal GBS immunization would prevent one-third of GBS cases and deaths in Uganda and Nigeria, where ANC4 is 50%, 42-43% in Guinea-Bissau (ANC4=65%), and 55-57% in Ghana (ANC4=87%). At a vaccination cost of $7/dose, maternal immunization would cost $320-$350/DALY averted in Guinea-Bissau, Nigeria, and Ghana, less than half these countries' GDP per capita. In Uganda, which has the lowest case fatality ratios, the cost would be $573/DALY. If the vaccine prevents a small proportion of stillbirths, it would be even more cost-effective. Vaccination cost/dose, disease incidence, and case fatality were key drivers of cost/DALY in sensitivity analyses. Maternal GBS immunization could be a cost-effective intervention in low-income sub-Saharan Africa, with cost-effectiveness ratios similar to other recently introduced vaccines

  16. Quantum key distribution for 10 Gb/s dense wavelength division multiplexing networks

    International Nuclear Information System (INIS)

    Patel, K. A.; Dynes, J. F.; Lucamarini, M.; Choi, I.; Sharpe, A. W.; Yuan, Z. L.; Shields, A. J.; Penty, R. V.

    2014-01-01

    We demonstrate quantum key distribution (QKD) with bidirectional 10 Gb/s classical data channels in a single fiber using dense wavelength division multiplexing. Record secure key rates of 2.38 Mbps and fiber distances up to 70 km are achieved. Data channels are simultaneously monitored for error-free operation. The robustness of QKD is further demonstrated with a secure key rate of 445 kbps over 25 km, obtained in the presence of data lasers launching conventional 0 dBm power. We discuss the fundamental limit for the QKD performance in the multiplexing environment

  17. A 1.5 Gb/s monolithically integrated optical receiver in the standard CMOS process

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xindong; Mao Luhong; Yu Changliang; Zhang Shilin; Xie Sheng, E-mail: xxd@tju.edu.c [School of Electronic Information Engineering, Tianjin University, Tianjin 300072 (China)

    2009-12-15

    A monolithically integrated optical receiver, including the photodetector, has been realized in Chartered 0.35 {mu}m EEPROM CMOS technology for 850 nm optical communication. The optical receiver consists of a differential photodetector, a differential transimpedance amplifier, three limiting amplifiers and an output circuit. The experiment results show that the receiver achieves an 875 MHz 3 dB bandwidth, and a data rate of 1.5 Gb/s is achieved at a bit-error-rate of 10{sup -9}. The chip dissipates 60 mW under a single 3.3 V supply. (semiconductor integrated circuits)

  18. A 1.5 Gb/s monolithically integrated optical receiver in the standard CMOS process

    International Nuclear Information System (INIS)

    Xiao Xindong; Mao Luhong; Yu Changliang; Zhang Shilin; Xie Sheng

    2009-01-01

    A monolithically integrated optical receiver, including the photodetector, has been realized in Chartered 0.35 μm EEPROM CMOS technology for 850 nm optical communication. The optical receiver consists of a differential photodetector, a differential transimpedance amplifier, three limiting amplifiers and an output circuit. The experiment results show that the receiver achieves an 875 MHz 3 dB bandwidth, and a data rate of 1.5 Gb/s is achieved at a bit-error-rate of 10 -9 . The chip dissipates 60 mW under a single 3.3 V supply. (semiconductor integrated circuits)

  19. 12.5 Gb/s carrier-injection silicon Mach—Zehnder optical modulator

    International Nuclear Information System (INIS)

    Chen Hongtao; Ding Jianfeng; Yang Lin

    2012-01-01

    We demonstrate a 12.5 Gb/s carrier-injection silicon Mach—Zehnder optical modulator. Under a nonreturn-zero (NRZ) pre-emphasized electrical drive signal with voltage swing of 6.3 V and forward bias of 0.7 V, the eye is clearly opened with an extinction ratio of 8.4 dB. The device exhibits high modulation efficiency, with a figure of merit V π L of 0.036 V·mm. (semiconductor devices)

  20. CHARACTERIZATION AND MODELING OF SOLITON TRANSMISSION AT 2.5 GB/S OVER 200 KM

    Directory of Open Access Journals (Sweden)

    KHALID A. S. AL-KHATEEB

    2010-09-01

    Full Text Available Soliton characteristics and soliton transmission have been simulated using a VPI simulator. Simulation was also used to construct and study a soliton communication system. Near soliton pulses emitted by an actively mode-locked laser is then compressed in a dispersion-compensating fiber (DCF to produce solitons. The effects of non-linearity and active pre-chirping of mode-locked laser diode sources were also investigated. Assessment on a modeled system using real data shows that propagation over 250 km at 2.5 Gb/s in standard fibers with 20 ps pulse widths is possible in the 1550 nm wavelength range.

  1. First Isolation of Streptococcus halichoeri and Streptococcus phocae from a Steller Sea Lion (Eumetopias jubatus) in South Korea.

    Science.gov (United States)

    Lee, Kichan; Kim, Ji-Yeon; Jung, Suk Chan; Lee, Hee-Soo; Her, Moon; Chae, Chanhee

    2016-01-01

    Streptococcus species are emerging potential pathogens in marine mammals. We report the isolation and identification of Streptococcus halichoeri and Streptococcus phocae in a Steller sea lion (Eumetopias jubatus) in South Korea.

  2. Directly Modulated and ER Enhanced Hybrid III-V/SOI DFB Laser Operating up to 20 Gb/s for Extended Reach Applications in PONs

    DEFF Research Database (Denmark)

    Cristofori, Valentina; Da Ros, Francesco; Chaibi, Mohamed E.

    2017-01-01

    We demonstrate error-free performance of an MRR filtered DML on the SOI platform over 40- and 81-km of SSW. The device operates up to 17.5 Gb/s over 81 km and 20 Gb/s over 40 km.......We demonstrate error-free performance of an MRR filtered DML on the SOI platform over 40- and 81-km of SSW. The device operates up to 17.5 Gb/s over 81 km and 20 Gb/s over 40 km....

  3. Optical Synchronization of a 10-G Ethernet Packet and Time-Division Multiplexing to a 50-Gb/s Signal Using an Optical Time Lens

    DEFF Research Database (Denmark)

    Hu, Hao; Laguardia Areal, Janaina; Palushani, Evarist

    2010-01-01

    A 10-G Ethernet packet with maximum packet size of 1518 bytes is synchronized to a master clock with 200-kHz frequency offset using a time lens. The input 10-Gb/s non-return-to-zero packet is at the same time converted into a return-to-zero (RZ) packet with a pulsewidth of 10 ps and then time......-division multiplexed with four 10-Gb/s optical time-division-multiplexing (OTDM) channels, thus constituting a 50-Gb/s OTDM serial signal. Error-free performances of the synchronized RZ packet and demultiplexed packet from the aggregated 50-Gb/s OTDM signal are achieved....

  4. Prevalence and drug susceptibility pattern of group B Streptococci (GBS) among pregnant women attending antenatal care (ANC) in Nekemte Referral Hospital (NRH), Nekemte, Ethiopia.

    Science.gov (United States)

    Mengist, Hylemariam Mihiretie; Zewdie, Olifan; Belew, Adugna; Dabsu, Regea

    2017-08-10

    The main objective of this study was to determine the prevalence and drug susceptibility pattern of group B Streptococci (GBS) among pregnant women. The specific objectives include; (1) To determine the prevalence of GBS colonization among pregnant women (2) To determine the drug susceptibility pattern of GBS among pregnant women and (3) To identify associated risk factors with GBS colonization among pregnant women. The median age of the participants was 24.5 years (range 16-38) and 86% participants were urban residents. The total prevalence of maternal GBS colonization from vaginal swab culture was 12.2% (22/180). The prevalence of GBS colonization rate was significantly higher in those pregnant women above 37 weeks of gestation [AOR, 95% CI 2.1 (1.2, 11.6), P = 0.03] and married ones [AOR, 95% CI 3.2 (1.8, 11.6), P < 0.021]. Twenty (91%) of GBS isolates were sensitive to vancomycin and the highest resistance was observed against penicillin G (77.3%). The prevalence of GBS colonization in this study was significantly high and differed by gestational age and marital status. None of the GBS isolates were resistant to vancomycin but higher resistance was shown against Penicillin G.

  5. Self-passivation Rule and the Effect of Post-treatment in GBs of Solar Cell Materials

    Science.gov (United States)

    Liu, Chengyan; Chen, Shiyou; Xiang, Hongjun; Gong, Xingao

    Grain boundaries (GBs) existing in polycrystalline semiconductors alloys inducing a great deal of deep defect levels are usually harmful to cells' photovoltaic performance. Experimental and theoretical investigations verified that these defect levels come from the GBs' dangling bonds. We find that, the defect levels in anion core of GB can be passivated by its cations, called by self-passivation. For instance, the post-treated by CdCl2, Cd can eliminate the defect levels by saturating Te dangling bonds in the grain boundary of CdTe. We verify that the idea of self-passivation rule can perfectly explain the benign GBs of CISe and CZTS by sodium treatment. The present work reveals a general mechanism about how dopants in GBs eliminate the defect states through passivating the dangling bonds in covalent polycrystalline semiconductors, and sheds light on how to passivate dangling bonds in GBs with alterative processes. National Science Foundation of China, international collaboration project of MOST, Pujiang plan, Program for Professor of Special Appointment (Eastern Scholar), and Shanghai Rising-star program.

  6. Genotyping-by-sequencing (GBS), an ultimate marker-assisted selection (MAS) tool to accelerate plant breeding.

    Science.gov (United States)

    He, Jiangfeng; Zhao, Xiaoqing; Laroche, André; Lu, Zhen-Xiang; Liu, HongKui; Li, Ziqin

    2014-01-01

    Marker-assisted selection (MAS) refers to the use of molecular markers to assist phenotypic selections in crop improvement. Several types of molecular markers, such as single nucleotide polymorphism (SNP), have been identified and effectively used in plant breeding. The application of next-generation sequencing (NGS) technologies has led to remarkable advances in whole genome sequencing, which provides ultra-throughput sequences to revolutionize plant genotyping and breeding. To further broaden NGS usages to large crop genomes such as maize and wheat, genotyping-by-sequencing (GBS) has been developed and applied in sequencing multiplexed samples that combine molecular marker discovery and genotyping. GBS is a novel application of NGS protocols for discovering and genotyping SNPs in crop genomes and populations. The GBS approach includes the digestion of genomic DNA with restriction enzymes followed by the ligation of barcode adapter, PCR amplification and sequencing of the amplified DNA pool on a single lane of flow cells. Bioinformatic pipelines are needed to analyze and interpret GBS datasets. As an ultimate MAS tool and a cost-effective technique, GBS has been successfully used in implementing genome-wide association study (GWAS), genomic diversity study, genetic linkage analysis, molecular marker discovery and genomic selection under a large scale of plant breeding programs.

  7. Streptococcus tangierensis sp. nov. and Streptococcus cameli sp. nov., two novel Streptococcus species isolated from raw camel milk in Morocco.

    Science.gov (United States)

    Kadri, Zaina; Vandamme, Peter; Ouadghiri, Mouna; Cnockaert, Margo; Aerts, Maarten; Elfahime, El Mostafa; Farricha, Omar El; Swings, Jean; Amar, Mohamed

    2015-02-01

    Biochemical and molecular genetic studies were performed on two unidentified Gram-stain positive, catalase and oxidase negative, non-hemolytic Streptococcus-like organisms recovered from raw camel milk in Morocco. Phenotypic characterization and comparative 16S rRNA gene sequencing demonstrated that the two strains were highly different from each other and that they did not correspond to any recognized species of the genus Streptococcus. Phylogenetic analysis based on 16S rRNA gene sequences showed the unidentified organisms each formed a hitherto unknown sub-line within the genus Streptococcus, displaying a close affinity with Streptococcus moroccensis, Streptococcus minor and Streptococcus ovis. DNA G+C content determination, MALDI-TOF mass spectrometry and biochemical tests demonstrated the bacterial isolates represent two novel species. Based on the phenotypic distinctiveness of the new bacteria and molecular genetic evidence, it is proposed to classify the two strains as Streptococcus tangierensis sp. nov., with CCMM B832(T) (=LMG 27683(T)) as the type strain, and Streptococcus cameli sp. nov., with CCMM B834(T) (=LMG 27685(T)) as the type strain.

  8. Broadband Packaging of Photodetectors for 100 Gb/s Ethernet Applications

    DEFF Research Database (Denmark)

    Jiang, Chenhui; Krozer, Viktor; Bach, Heinz-Gunter

    2013-01-01

    The packing structure of functional modules is a major limitaion in achieving a desired performance for 100 Gb/s ethernet applications. This paper presents a methodology of developing advanced packaging of photodetectors (PDs) for high-speed data transmission applications by using 3-D electromagn......The packing structure of functional modules is a major limitaion in achieving a desired performance for 100 Gb/s ethernet applications. This paper presents a methodology of developing advanced packaging of photodetectors (PDs) for high-speed data transmission applications by using 3-D...... electromagnetic (EM) simulations. A simplified model of the PD module is first used to analyze and optimize packaging structures and propose an optimal packaging design based on the simplified model. Although a PD module with improved performance proved the success of the optimal packaging design, the simplified...... of limiting the bandwidth of PD modules. After eliminating the mode mismatch effect by improving the chip-conductor-backed coplanar waveguide transition, a final optimal packaging structure is implemented for the PD module with reduced attenuation up to 100 GHz and a broader 3-dB bandwidth of more than 90 GHz...

  9. 45 Gb/s low complexity optical front-end for soft-decision LDPC decoders.

    Science.gov (United States)

    Sakib, Meer Nazmus; Moayedi, Monireh; Gross, Warren J; Liboiron-Ladouceur, Odile

    2012-07-30

    In this paper a low complexity and energy efficient 45 Gb/s soft-decision optical front-end to be used with soft-decision low-density parity-check (LDPC) decoders is demonstrated. The results show that the optical front-end exhibits a net coding gain of 7.06 and 9.62 dB for post forward error correction bit error rate of 10(-7) and 10(-12) for long block length LDPC(32768,26803) code. The performance over a hard decision front-end is 1.9 dB for this code. It is shown that the soft-decision circuit can also be used as a 2-bit flash type analog-to-digital converter (ADC), in conjunction with equalization schemes. At bit rate of 15 Gb/s using RS(255,239), LDPC(672,336), (672, 504), (672, 588), and (1440, 1344) used with a 6-tap finite impulse response (FIR) equalizer will result in optical power savings of 3, 5, 7, 9.5 and 10.5 dB, respectively. The 2-bit flash ADC consumes only 2.71 W at 32 GSamples/s. At 45 GSamples/s the power consumption is estimated to be 4.95 W.

  10. 100-Gb/s InP DP-IQ modulator for small-form-factor pluggable coherent transceivers

    Science.gov (United States)

    Kikuchi, Nobuhiro; Ogiso, Yoshihiro; Yamada, Eiichi

    2016-02-01

    We developed a compact InP-based DP-IQ modulator for small-form-factor pluggable coherent transceivers. The modulator achieves 112-Gb/s DP-QPSK modulation with a driving voltage of 6 Vppd. In addition, it provides 86-Gb/s DP-16 QAM signal generation and 240-km transmission with negligible degradation of BER performance. The halfwavelength voltage of our recent device is 1.9 V, and a high median extinction ratio of over 32 dB was achieved for more than 1,400 child MZ modulators. We have also proposed an athermal InP-based twin IQ modulator that enables us to use a modulator in a TEC-free operation. It contributes to lowering the power consumption of transceivers. Under a constant driving condition, there is little change in 56-Gb/s x 2 QPSK modulation characteristics in the range of 20 to 80°C.

  11. Functional analysis of the glycogen binding subunit CG9238/Gbs-70E of protein phosphatase 1 in Drosophila melanogaster.

    Science.gov (United States)

    Kerekes, Éva; Kókai, Endre; Páldy, Ferenc Sándor; Dombrádi, Viktor

    2014-06-01

    The product of the CG9238 gene that we termed glycogen binding subunit 70E (Gbs-70E) was characterized by biochemical and molecular genetics methods. The interaction between Gbs-70E and all catalytic subunits of protein phosphatase 1 (Pp1-87B, Pp1-9C, Pp1-96A and Pp1-13C) of Drosophila melanogaster was confirmed by pairwise yeast two-hybrid tests, co-immunoprecipitation and pull down experiments. The binding of Gbs-70E to glycogen was demonstrated by sedimentation analysis. With RT-PCR we found that the mRNAs coding for the longer Gbs-70E PB/PC protein were expressed in all developmental stages of the fruit flies while the mRNA for the shorter Gbs-70E PA was restricted to the eggs and the ovaries of the adult females. The development specific expression of the shorter splice variant was not conserved in different Drosophila species. The expression level of the gene was manipulated by P-element insertions and gene deletion to analyze the functions of the gene product. A small or moderate reduction in the gene expression resulted in no significant changes, however, a deletion mutant expressing very low level of the transcript lived shorter and exhibited reduced glycogen content in the imagos. In addition, the gene deletion decreased the fertility of the fruit flies. Our results prove that Gbs-70E functions as the glycogen binding subunit of protein phosphatase 1 that regulates glycogen content and plays a role in the development of eggs in D. melanogaster. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Surface-bound capsular polysaccharide of type Ia group B Streptococcus mediates C1 binding and activation of the classic complement pathway

    International Nuclear Information System (INIS)

    Levy, N.J.; Kasper, D.L.

    1986-01-01

    The role of surface-bound type Ia group B Streptococcus (GBS) capsular polysaccharide in anti-body-independent binding of C1 and activation of the classic component pathway was investigated. In a radiolabeled bacterial-polymorphonuclear leukocyte (PMN) association assay, a measure of bacterial opsonization, preincubation of 3 H-type Ia GBS with purified F(ab') 2 to the organism blocked the association of the bacteria with PMN', and the inhibitory effect was dose dependent. The specificity of F(ab') 2 blocking was shown after adsorption of F(ab') 2 with type Ia polysaccharide-sensitized erythrocytes. Polysaccharide-adsorbed F(ab') 2 had a 70% decrease in ability to block the association of bacteria with PMN. Neuraminidase digestion removed 80% of the terminal sialic acid residues from the native polysaccharide. These neuraminidase-digested organisms had a 72% decrease in binding and transfer of purified C1 compared with non-enzyme-treated organisms. Type Ia capsular polysaccharide bound to sheep erythrocytes promoted classic complement pathway-mediated hemolysis of the cells. The role of C1 inhibitor (INH) in modulation of C1 activation by the organisms was investigated. The possibility existed that the C1 INH could be bound by the bacteria, allowing C1 activation to occur in the fluid phase. The inhibitor was purified from human serum, and its activity was measured before and after incubation with type Ia GBS. The organisms had no effect on C1 INH activity. Thus surface-bound capsular polysacchardie of type Ia GBS mediates C1 binding and classic pathway activation, and this does not involve the C1 INH

  13. Multiple lung abscesses caused by Streptococcus constellatus

    Directory of Open Access Journals (Sweden)

    Vanina Rognoni

    2018-02-01

    Full Text Available Despite numerous descriptions of body abscesses produced by Streptococcus milleri group bacteria, lung abscesses caused by this group remain under-reported and the clinical and laboratory features have yet to be fully characterised. We present the case of a patient admitted with lung multiple abscesses produced by Streptococcus constellatus.

  14. Group A Streptococcus vulvovaginitis in breastfeeding women.

    Science.gov (United States)

    Rahangdale, Lisa; Lacy, Judith; Hillard, Paula A

    2008-08-01

    Group A beta-hemolytic streptococcus-associated vulvovaginitis is uncommon in adult women. Clinicians should include group A beta-hemolytic streptococcus as a possible cause of vulvovaginal symptoms in breastfeeding women. Along with appropriate antibiotic therapy, vaginal estrogen therapy may be considered to diminish susceptibility to recurrent infection in women with vaginal atrophy.

  15. Streptococcus suis meningitis, a poacher's risk

    NARCIS (Netherlands)

    Halaby, T.; Hoitsma, E.; Hupperts, R.; Spanjaard, L.; Luirink, M.; Jacobs, J.

    2000-01-01

    Streptococcus suis infection is a zoonosis that has been mainly reported in pig-rearing and pork-consuming countries. The most common disease manifestation is meningitis, often associated with cochleovestibular signs. The causative agent is Streptococcus suis serotype 2, found as a commensal in the

  16. Wavelength conversion of 80 Gb/s RZ-DPSK Pol-MUX signals in a silicon nanowire

    DEFF Research Database (Denmark)

    Vukovic, Dragana; Peucheret, Christophe; Oxenløwe, Leif Katsuo

    2014-01-01

    All-optical wavelength conversion of 80 Gb/s RZ-DPSK polarization multiplexed signals is demonstrated in a silicon nanowire using an angled-pump scheme. The quality of the converted signal is characterized through BER measurements for the first time.......All-optical wavelength conversion of 80 Gb/s RZ-DPSK polarization multiplexed signals is demonstrated in a silicon nanowire using an angled-pump scheme. The quality of the converted signal is characterized through BER measurements for the first time....

  17. 41.6 Gb/s RZ-DPSK to NRZ-DPSK Format Conversion in a Microring Resonator

    DEFF Research Database (Denmark)

    Xiong, Meng; Ozolins, Oskars; Ding, Yunhong

    2012-01-01

    RZ-DPSK to NRZ-DPSK format conversion in a silicon microring resonator is demonstrated experimentally for the first time at 41.6 Gb/s. The converted signal eye diagrams and bit-error-rate measurements show the good performance of the scheme........RZ-DPSK to NRZ-DPSK format conversion in a silicon microring resonator is demonstrated experiment