1651
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Usein CR, Grigore L, Georgescu R, Cristea V, Bãltoiu M, Strãuţ M. Molecular characterization of adult-colonizing Streptococcus agalactiae from an area-based surveillance study in Romania. Eur J Clin Microbiol Infect Dis 2012; 31:2301-10. [DOI: 10.1007/s10096-012-1569-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 01/26/2012] [Indexed: 11/30/2022]
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1652
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Freudenstein D, Reinshagen K, Petzold A, Debus A, Schroten H, Tenenbaum T. Ultra late onset group B streptococcal sepsis with acute renal failure in a child with urethral obstruction: a case report. J Med Case Rep 2012; 6:68. [PMID: 22348641 PMCID: PMC3298714 DOI: 10.1186/1752-1947-6-68] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 02/20/2012] [Indexed: 11/10/2022] Open
Abstract
Introduction Group B streptococci are a well-known cause of early and late onset sepsis. In neonates and older children gram-negative bacteria are mostly found in urinary tract infections and urosepsis. In adults predisposing factors for group B streptococci urinary tract infection may include diabetes mellitus and chronic renal failure. Case presentation We present a rare case of a five-month-old Caucasian boy with ultra late onset urosepsis and acute renal failure caused by group B streptococci serotype V. Excretion urography showed a subvesical obstruction that consequently was surgically corrected after antibiotic treatment of the acute infection. Conclusions Group B streptococci serotype V, urogenitary tract malformations, previous hospitalization and medical interventions may be important risk factors for the development of ultra late onset Group B streptococci sepsis in non-neonates.
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Affiliation(s)
- Daniela Freudenstein
- University Children's Hospital Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim Germany.
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1653
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Edmond KM, Kortsalioudaki C, Scott S, Schrag SJ, Zaidi AKM, Cousens S, Heath PT. Group B streptococcal disease in infants aged younger than 3 months: systematic review and meta-analysis. Lancet 2012; 379:547-56. [PMID: 22226047 DOI: 10.1016/s0140-6736(11)61651-6] [Citation(s) in RCA: 420] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Despite widespread use of intrapartum antibiotic prophylaxis, group B streptococcus remains a leading cause of morbidity and mortality in infants in Europe, the Americas, and Australia. However, estimates of disease burden in many countries outside of these regions is not available. We aimed to examine the current global burden of invasive disease and the serotype distribution of group B streptococcus isolates. METHODS We searched Medline, Embase, and Wholis databases for studies on invasive early-onset (day 0-6) and late-onset (day 7-89) group B streptococcal disease. Eligible studies were those that described incidence, deaths, or serotypes. We also reviewed reference lists and contacted experts to seek unpublished data and data missed by our search. Random effects meta-analysis was used to pool data. FINDINGS 74 studies met the inclusion criteria; 56 studies reported incidence, 29 case fatality, and 19 serotype distribution. An additional search for studies that reported serotype distribution from Jan 1, 1980, yielded a total of 38 articles. Only five low-income countries were represented in the review and contributed 5% weight to the meta-analysis. 47 (69%) studies reported use of any intrapartum antibiotic prophylaxis. Substantial heterogeneity existed between studies. Mean incidence of group B streptococcus in infants aged 0-89 days was 0·53 per 1000 livebirths (95% CI 0·44-0·62) and the mean case fatality ratio was 9·6% (95% CI 7·5-11·8). Incidence of early-onset group B streptococcus (0·43 per 1000 livebirths [95% CI 0·37-0·49]) and case fatality (12·1%, [6·2-18·3]) were two-times higher than late-onset disease. Serotype III (48·9%) was the most frequently identified serotype in all regions with available data followed by serotypes Ia (22·9%), Ib (7·0%), II (6·2%), and V (9·1%). Studies that reported use of any intrapartum antibiotic prophylaxis were associated with lower incidence of early-onset group B streptococcus (0·23 per 1000 livebirths [95% CI 0·13-0·59]) than studies in which patients did not use prophylaxis (0·75 per 1000 livebirths [0·58-0·89]). INTERPRETATION More high-quality studies are needed to accurately estimate the global burden of group B streptococcus, especially in low-income countries. A conjugate vaccine incorporating five serotypes (Ia, Ib, II, III, V) could prevent most global group B streptococcal disease. FUNDING Child Epidemiology Reference Group (CHERG), WHO.
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Affiliation(s)
- Karen M Edmond
- London School of Hygiene and Tropical Medicine, London, UK.
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1654
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Berardi A, Di Fazzio G, Gavioli S, Di Grande E, Groppi A, Papa I, Piccinini G, Simoni A, Tridapalli E, Volta A, Facchinetti F, Ferrari F. Universal antenatal screening for group B streptococcus in Emilia-Romagna. J Med Screen 2012; 18:60-4. [PMID: 21852697 DOI: 10.1258/jms.2011.011023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Group B streptococcus (GBS) is a leading cause of severe infections in newborns. Intrapartum antibiotic chemoprophylaxis (IAP) reduces the rate of early-onset disease. The aim of this study is to determine the degree of clinicians' compliance with the suggested protocol for GBS prevention in Emilia-Romagna (Italy). METHODS Characteristics of each delivery were prospectively recorded in the period between October 2005 to December 2005. Standardized pro-forma were used to collect data. RESULTS Among 5118 babies, 7.2% (369) were preterm and 92.3% were born at term (4749). Antenatal screening was performed in 86.6% of women who delivered at term, of which 18.1% were GBS culture-positive. Information regarding culture site was available in 93.2% of women screened and recto-vaginal cultures were documented in 42.7%. IAP was administered to 28.7% of 3937 women at term who had either spontaneous delivery or emergency caesarean section. In this cohort, 15.9% were diagnosed GBS culture-positive, of which 92.6% received IAP. Prophylaxis was also administered to 8.4% (331) of women for no apparent reason. Compared with tertiary level hospitals, women delivering in primary/secondary hospitals were more likely to be both GBS screened (P < 0.0001; OR 3.04; CI 2.33-3.97) and to receive prophylaxis ≥4 hours before delivery (P = 0.0025; OR 1.57; CI 1.17-2.12). CONCLUSIONS GBS screening was performed in >85% of women and >90% of culture-positive women received prophylaxis. However, there is a need to educate clinicians about protocol adherence, as most cultures were suboptimal and cases of unnecessary IAP were administered. The screening was more effective in hospitals with fewer deliveries.
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Affiliation(s)
- Alberto Berardi
- Unità Operativa di Terapia Intensiva Neonatale, Azienda Ospedaliero-Universitaria Policlinico di Modena, Via del Pozzo, 71-41100 Modena (MO), Italy.
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1655
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Berger MB, Xu X, Williams JA, Van de Ven CJM, Mozurkewich EL. Early hospital discharge of infants born to group B streptococci-positive mothers: a decision analysis. BJOG 2012; 119:439-48. [PMID: 22251453 DOI: 10.1111/j.1471-0528.2011.03249.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To compare the cost-effectiveness of an additional 24-hour inpatient observation for asymptomatic term neonates born to group B streptococcus (GBS)-colonised mothers with adequate intrapartum antibiotic prophylaxis (IAP) after an initial 24-hour in-hospital observation. DESIGN Cost-effectiveness analysis from a societal perspective. SETTING United States. POPULATION Asymptomatic term neonates born to GBS-colonised mothers with IAP after an initial 24-hour in-hospital observation. METHODS Monte Carlo simulation for a decision tree model incorporating the following chance events: development of GBS sepsis during the second 24 hours of life, development of GBS sepsis between 48 hours and 7 days of life, prompt versus delayed treatment for sepsis, neonatal mortality and long-term health sequelae. MAIN OUTCOME MEASURES Expected cost and quality-adjusted life years (QALYs), Incremental cost-effectiveness ratio (ICER). RESULTS Delayed, versus early, hospital discharge results in similar mean expected QALYs, but substantially higher expected cost. The mean difference in QALY is 0.00016 (95% CI 0.00005-0.00040), whereas the mean difference in cost is $1170.96 (95% CI $750.13-1584.32). The ICER is estimated to be $9,771,520.87 per QALY (95% CI $2,573,139.89-24,407,017.82). The proportion of early-onset GBS that develops during the second 24 hours of life, the cost of 24 hours of inpatient observation, and the probability of long-term sequelae following prompt versus delayed treatment play important roles in determining the cost-effectiveness of delayed hospital discharge. CONCLUSION Cost-effectiveness analysis suggests that with adequate IAP, discharging asymptomatic term neonates to home after 24 hours is the preferred approach compared with 48 hours inpatient observation.
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Affiliation(s)
- M B Berger
- Department of Obstetrics and Gynecology, University of Michigan Health System, L4000 Women’s Hospital, 1500 East Medical Center Drive, Ann Arbor, MI 48109-5276, USA.
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1656
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Dominance of serotype Ia among group B Streptococci causing invasive infections in nonpregnant adults in Portugal. J Clin Microbiol 2012; 50:1219-27. [PMID: 22219307 DOI: 10.1128/jcm.05488-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The population of group B streptococci (GBS) associated with invasive infections in nonpregnant adults from 2001 to 2008 was analyzed in isolates submitted from 24 hospital laboratories in Portugal (n = 225). The isolates were characterized by antimicrobial susceptibility, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and surface protein gene profiling. GBS invasive cases were found more frequently among men in all age groups. In addition, serotype Ia was the most frequent in our collection, whereas serotype V is dominant elsewhere. Serotype Ia was represented mainly by a single PFGE cluster defined by sequence type 23 (ST23) and surface protein gene eps and by ST24 and bca, similarly to neonatal invasive infections in Portugal, indicating that the same genetic lineages can be responsible for both vaginal colonization and invasive disease in all age groups. In contrast, the hypervirulent serotype III/ST17 neonatal lineage was responsible for a minority of infections. Serotype V isolates were distributed into two genetic lineages, one defined by ST1 and surface protein gene alp3 and macrolide resistant, and another presenting with ST2 and eps and fully susceptible to all antimicrobials tested. The erm(TR) gene was the most frequently found among erythromycin-resistant isolates, while the bovine-associated tet(O) gene was found in a minority of tetracycline-resistant isolates. Our data emphasize the importance of local identification of the genetic lineages responsible for GBS invasive infections in nonpregnant adults. The dominance of serotype Ia in invasive disease in Portugal highlights the importance of this serotype in GBS pathogenesis.
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1657
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Palumbo E, Fiaschi L, Brunelli B, Marchi S, Savino S, Pizza M. Antigen identification starting from the genome: a "Reverse Vaccinology" approach applied to MenB. Methods Mol Biol 2012; 799:361-403. [PMID: 21993656 DOI: 10.1007/978-1-61779-346-2_21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Most of the vaccines available today, albeit very effective, have been developed using traditional "old-style" methodologies. Technologies developed in recent years have opened up new perspectives in the field of vaccinology and novel strategies are now being used to design improved or new vaccines against infections for which preventive measures do not exist. The Reverse Vaccinology (RV) approach is one of the most powerful examples of biotechnology applied to the field of vaccinology for identifying new protein-based vaccines. RV combines the availability of genomic data, the analyzing capabilities of new bioinformatic tools, and the application of high throughput expression and purification systems combined with serological screening assays for a coordinated screening process of the entire genomic repertoire of bacterial, viral, or parasitic pathogens. The application of RV to Neisseria meningitidis serogroup B represents the first success of this novel approach. In this chapter, we describe how this revolutionary approach can be easily applied to any pathogen.
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1658
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Done SL. Fetal and neonatal bone health: update on bone growth and manifestations in health and disease. Pediatr Radiol 2012; 42 Suppl 1:S158-76. [PMID: 22395728 DOI: 10.1007/s00247-011-2251-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 08/02/2011] [Accepted: 08/30/2011] [Indexed: 12/19/2022]
Abstract
The neonatal period is classically described as the first 28 days of life, but owing to the fact that changes in skeletal tissue occur at a somewhat slower pace than those of other organ systems, events of the first few months are considered herein. Neonatal bone health is a problem of growing interest and concern because of the increasing recognition of its impact upon childhood, adolescent and even adult bone health. Osteoporosis in adulthood often has its roots in childhood and some forms may be prevented by proper attention to neonatal and childhood bone health. The premature infant likely suffers lifelong decreased bone mineral density as a result of its early birth and lack of adequate mineral stores that are typically present in full-term infants. Adequate embryogenesis, growth and development of the skeletal system are multifactorial and under the influence of a host of genes, growth factors and enzymes. The evaluation of skeletal dysplasias and their recognition are beyond the scope of this paper and will not be considered in this discussion. Here the focus will be on the adequacy of mineralization and metabolic aspects of the growth and development of the fetal and neonatal skeleton, the effect of birth, both preterm and term, maternal illness and health as well as infant diseases.
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Affiliation(s)
- Stephen L Done
- Department of Radiology, Seattle Children's Hospital, University of Washington, R5417, 4800 Sandpoint Way NE, Seattle, WA 98105, USA.
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1659
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Abstract
PURPOSE OF REVIEW Many physiologic and pathophysiologic processes are modulated by arginine availability, which can be regulated by arginase. An understanding of the conditions that result in elevated arginase activity as well as the consequences of arginine deficiency is essential for design of effective nutritional support for disease. This review will emphasize recent findings regarding effects of plasma arginase and arginine deficiencies in disease. RECENT FINDINGS Elevations in plasma arginase, derived primarily from hemolysis of red blood cells or liver damage, that are associated with arginine deficiency have been identified in an increasing number of diseases and conditions. Arginine insufficiency not only can activate a stress kinase pathway that impairs function of T lymphocytes but it also can inhibit the mitogen-activated protein kinase signaling pathway required for macrophage production of cytokines in response to bacterial endotoxin/lipopolysaccharide. SUMMARY There are at least two broad categories of arginine deficiency syndromes, involving either T-cell dysfunction or endothelial dysfunction, depending on the disease context in which arginine deficiency occurs. There is limited information regarding the safety and efficacy of supplementation with arginine or its precursor citrulline in ameliorating arginine deficiency in specific diseases, indicating the need for further studies.
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Affiliation(s)
- Sidney M Morris
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
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1660
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Tazi A, Bellais S, Tardieux I, Dramsi S, Trieu-Cuot P, Poyart C. Group B Streptococcus surface proteins as major determinants for meningeal tropism. Curr Opin Microbiol 2011; 15:44-9. [PMID: 22206860 DOI: 10.1016/j.mib.2011.12.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 11/30/2011] [Accepted: 12/01/2011] [Indexed: 11/30/2022]
Abstract
Streptococcus agalactiae (group B Streptococcus, GBS), a normal constituent of the intestinal microbiota is the major cause of human neonatal infections and a worldwide spread 'hypervirulent' clone, GBS ST-17, is strongly associated with neonatal meningitis. Adhesion to epithelial and endothelial cells constitutes a key step of the infectious process. Therefore GBS surface-anchored proteins are obvious potential adhesion mediators of barrier crossing and determinant of hypervirulence. This review addresses the most recent molecular insights gained from studies on GBS surface proteins proven to be involved in the crossing of the brain-blood barrier and emphasizes on the specificity of a hypervirulent clone that displays meningeal tropism.
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Affiliation(s)
- Asmaa Tazi
- Institut Cochin, Université Paris Descartes Sorbonne Paris Cité, CNRS (UMR 8104), Paris, France
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1661
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Dong JY, Qin LQ, Zhang Z, Zhao Y, Wang J, Arigoni F, Zhang W. Effect of oral L-arginine supplementation on blood pressure: a meta-analysis of randomized, double-blind, placebo-controlled trials. Am Heart J 2011; 162:959-65. [PMID: 22137067 DOI: 10.1016/j.ahj.2011.09.012] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 09/13/2011] [Indexed: 12/16/2022]
Abstract
BACKGROUND Previous studies suggest that L-arginine, an amino acid and a substrate of nitric oxide synthase, may have blood pressure (BP)-lowering effect. Because some studies were performed with limited number of patients with hypertension and therefore limited statistical power with sometimes inconsistent results, we aimed to examine the effect of oral L-arginine supplementation on BP by conducting a meta-analysis of randomized, double-blind, placebo-controlled trials. METHODS PubMed, Cochrane Central Register of Controlled Trials, and the ClinicalTrials.gov databases were searched through June 2011 to identify randomized, double-blind, placebo-controlled trials of oral L-arginine supplementation on BP in humans. We also reviewed reference lists of obtained articles. Either a fixed-effects or, in the presence of heterogeneity, a random-effects model was used to calculate the combined treatment effect. RESULTS We included 11 randomized, double-blind, placebo-controlled trials involving 387 participants with oral L-arginine intervention ranging from 4 to 24 g/d. Compared with placebo, L-arginine intervention significantly lowered systolic BP by 5.39 mm Hg (95% CI -8.54 to -2.25, P = .001) and diastolic BP by 2.66 mm Hg (95% CI -3.77 to -1.54, P < .001). Sensitivity analyses restricted to trials with a duration of 4 weeks or longer and to trials in which participants did not use antihypertensive medications yielded similar results. Meta-regression analysis suggested an inverse, though insignificant (P = .13), relation between baseline systolic BP and net change in systolic BP. CONCLUSIONS This meta-analysis provides further evidence that oral L-arginine supplementation significantly lowers both systolic and diastolic BP.
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1662
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Imperi M, Gherardi G, Berardi A, Baldassarri L, Pataracchia M, Dicuonzo G, Orefici G, Creti R. Invasive neonatal GBS infections from an area-based surveillance study in Italy. Clin Microbiol Infect 2011; 17:1834-9. [PMID: 21722258 DOI: 10.1111/j.1469-0691.2011.03479.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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1663
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Madureira P, Andrade EB, Gama B, Oliveira L, Moreira S, Ribeiro A, Correia-Neves M, Trieu-Cuot P, Vilanova M, Ferreira P. Inhibition of IL-10 production by maternal antibodies against Group B Streptococcus GAPDH confers immunity to offspring by favoring neutrophil recruitment. PLoS Pathog 2011; 7:e1002363. [PMID: 22114550 PMCID: PMC3219712 DOI: 10.1371/journal.ppat.1002363] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 09/22/2011] [Indexed: 11/19/2022] Open
Abstract
Group B Streptococcus (GBS) is the leading cause of neonatal pneumonia, septicemia, and meningitis. We have previously shown that in adult mice GBS glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an extracellular virulence factor that induces production of the immunosuppressive cytokine interleukin-10 (IL-10) by the host early upon bacterial infection. Here, we investigate whether immunity to neonatal GBS infection could be achieved through maternal vaccination against bacterial GAPDH. Female BALB/c mice were immunized with rGAPDH and the progeny was infected with a lethal inoculum of GBS strains. Neonatal mice born from mothers immunized with rGAPDH were protected against infection with GBS strains, including the ST-17 highly virulent clone. A similar protective effect was observed in newborns passively immunized with anti-rGAPDH IgG antibodies, or F(ab')2 fragments, indicating that protection achieved with rGAPDH vaccination is independent of opsonophagocytic killing of bacteria. Protection against lethal GBS infection through rGAPDH maternal vaccination was due to neutralization of IL-10 production soon after infection. Consequently, IL-10 deficient (IL-10−/−) mice pups were as resistant to GBS infection as pups born from vaccinated mothers. We observed that protection was correlated with increased neutrophil trafficking to infected organs. Thus, anti-rGAPDH or anti-IL-10R treatment of mice pups before GBS infection resulted in increased neutrophil numbers and lower bacterial load in infected organs, as compared to newborn mice treated with the respective control antibodies. We showed that mothers immunized with rGAPDH produce neutralizing antibodies that are sufficient to decrease IL-10 production and induce neutrophil recruitment into infected tissues in newborn mice. These results uncover a novel mechanism for GBS virulence in a neonatal host that could be neutralized by vaccination or immunotherapy. As GBS GAPDH is a structurally conserved enzyme that is metabolically essential for bacterial growth in media containing glucose as the sole carbon source (i.e., the blood), this protein constitutes a powerful candidate for the development of a human vaccine against this pathogen. Streptococcus agalactiae (Group B streptococcus, GBS) is the leading infectious cause of morbidity and mortality among neonates. However, there is still no satisfactory explanation of why neonates are so susceptible to GBS infections. Intrapartum antibiotic prophylaxis (IAP) was implemented in many countries but led to the emergence of antibiotic-resistant GBS strains. Therefore, maternal vaccination represents an attractive alternative to IAP. Here, we show that the high susceptibility of newborn mice to GBS infections is associated with their propensity to produce elevated amounts of immunosuppressive cytokine IL-10. We also demonstrate that IL-10 impairs neutrophil recruitment into infected organs thus preventing bacterial clearance. We identified extracellular GAPDH as the GBS factor that induces the high IL-10 production detected early upon neonatal infection. We show that maternal vaccination with recombinant GAPDH confers robust protective immunity against lethal infection with a GBS hyper-virulent strain in mice offspring. This protection can also be obtained either by antibody neutralization of GBS GAPDH or by blocking IL-10 binding to its receptor. As GBS GAPDH is an essential protein for bacterial growth, it is present in all GBS strains and thus constitutes an appropriate target antigen for a global effective vaccine against this pathogen.
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Affiliation(s)
- Pedro Madureira
- ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Elva Bonifácio Andrade
- ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Bernardo Gama
- ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Liliana Oliveira
- ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Susana Moreira
- IBB, Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Adília Ribeiro
- ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Margarida Correia-Neves
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, CNRS URA 2172, Paris, France
| | - Manuel Vilanova
- ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Porto, Portugal
| | - Paula Ferreira
- ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
- IBMC – Instituto de Biologia Molecular e Celular, Porto, Portugal
- * E-mail:
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1664
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Prust MJ, Gropman AL, Hauser N. New frontiers in neuroimaging applications to inborn errors of metabolism. Mol Genet Metab 2011; 104:195-205. [PMID: 21778100 PMCID: PMC3758691 DOI: 10.1016/j.ymgme.2011.06.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 06/25/2011] [Accepted: 06/26/2011] [Indexed: 12/21/2022]
Abstract
Most inborn errors of metabolism (IEMs) are associated with potential for injury to the developing central nervous system resulting in chronic encephalopathy, though the etiopathophysiology of neurological injury have not been fully established in many disorders. Shared mechanisms can be envisioned such as oxidative injury due to over-activation of N-Methyl-d-Aspartate (NMDA) receptors with subsequent glutamatergic damage, but other causes such as energy depletion or inflammation are possible. Neuroimaging has emerged as a powerful clinical and research tool for studying the brain in a noninvasive manner. Several platforms exist to study neural networks underlying cognitive processes, white matter/myelin microstructure, and cerebral metabolism in vivo. The scope and limitations of these methods will be discussed in the context of valuable information they provide in the study and management of selected inborn errors of metabolism. This review is not meant to be an exhaustive coverage of diagnostic findings on MRI in multiple IEMs, but rather to illustrate how neuroimaging modalities beyond T1 and T2 images, can add depth to an understanding of the underlying brain changes evoked by the selected IEMs. Emphasis will be placed on techniques that are available in the clinical setting. Though technically complex, many of these modalities have moved - or soon will - to the clinical arena.
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Affiliation(s)
- Morgan J. Prust
- Department of Neurology, Children’s National Medical Center, Washington, D.C., USA
| | - Andrea L. Gropman
- Department of Neurology, Children’s National Medical Center, Washington, D.C., USA
- Medical Genetics Branch, National Human Genome Research Institute, USA
- Corresponding author at: Department of Neurology, Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, D.C. 20010, USA. Fax: +1 202 476 5226. (A.L. Gropman)
| | - Natalie Hauser
- Medical Genetics Branch, National Human Genome Research Institute, USA
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1665
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Necchi F, Nardi-Dei V, Biagini M, Assfalg M, Nuccitelli A, Cozzi R, Norais N, Telford JL, Rinaudo CD, Grandi G, Maione D. Sortase A substrate specificity in GBS pilus 2a cell wall anchoring. PLoS One 2011; 6:e25300. [PMID: 21991306 PMCID: PMC3186789 DOI: 10.1371/journal.pone.0025300] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/31/2011] [Indexed: 11/18/2022] Open
Abstract
Streptococcus agalactiae, also referred to as Group B Streptococcus (GBS), is one of the most common causes of life-threatening bacterial infections in infants. In recent years cell surface pili have been identified in several Gram-positive bacteria, including GBS, as important virulence factors and promising vaccine candidates. In GBS, three structurally distinct types of pili have been discovered (pilus 1, 2a and 2b), whose structural subunits are assembled in high-molecular weight polymers by specific class C sortases. In addition, the highly conserved housekeeping sortase A (SrtA), whose main role is to link surface proteins to bacterial cell wall peptidoglycan by a transpeptidation reaction, is also involved in pili cell wall anchoring in many bacteria. Through in vivo mutagenesis, we demonstrate that the LPXTG sorting signal of the minor ancillary protein (AP2) is essential for pilus 2a anchoring. We successfully produced a highly purified recombinant SrtA (SrtA(ΔN40)) able to specifically hydrolyze the sorting signal of pilus 2a minor ancillary protein (AP2-2a) and catalyze in vitro the transpeptidation reaction between peptidoglycan analogues and the LPXTG motif, using both synthetic fluorescent peptides and recombinant proteins. By contrast, SrtA(ΔN40) does not catalyze the transpeptidation reaction with substrate-peptides mimicking sorting signals of the other pilus 2a subunits (the backbone protein and the major ancillary protein). Thus, our results add further insight into the proposed model of GBS pilus 2a assembly, in which SrtA is required for pili cell wall covalent attachment, acting exclusively on the minor accessory pilin, representing the terminal subunit located at the base of the pilus.
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Affiliation(s)
| | | | | | - Michael Assfalg
- Department of Biotechnology, University of Verona, Verona, Italy
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1666
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The use of blood counts and blood cultures to screen neonates born to partially treated group B Streptococcus-carrier mothers for early-onset sepsis: is it justified? Pediatr Infect Dis J 2011; 30:840-3. [PMID: 21617574 DOI: 10.1097/inf.0b013e3182223586] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND No clear recommendations exist regarding the approach to evaluate neonates born to partially treated group B Streptococcus (GBS)-carrier mothers for early-onset GBS (EO-GBS) sepsis. OBJECTIVE To determine the yield and drawbacks of screening, all neonates born to GBS-carrier mothers who received only one dose of IV antibiotic, less than 4 hours, before delivery (partially treated). METHODS A retrospective analysis was performed of all complete blood counts (CBCs) and blood cultures obtained from infants born during the period 2005 to 2009 to GBS-positive screened mothers treated with only one dose of antibiotic prior to delivery. A review was conducted of all neonatal EO-GBS sepsis cases during the study period. RESULTS : Of 5845 GBS-carrier mothers, 1648 (28%) received only one dose of antibiotic less than 4 hours before delivery. We traced the CBCs and blood cultures, which were taken from 1413/1648 (86%) infants after birth. In 234 (18%) of these 1413 neonates, a second CBC sample was taken due to abnormal result of the CBC (leukocytosis, leukopenia, or thrombocytopenia) or secondary to technical failure in obtaining the blood. None of the blood cultures taken in that screening protocol was GBS positive, but in 10 cases contamination with coagulase-negative Staphylococcus was reported. During the study period, EO-GBS sepsis was diagnosed in 11 neonates; all had clinical symptoms upon presentation. CONCLUSIONS The use of CBC and blood culture to screen neonates born to GBS-carrier mothers who received only one dose of IV antibiotic before delivery led to a negligible clinical yield and a high rate of technical failure. Although these findings are in line with the recent change in the Centers for Disease Control guidelines, they put in question the cost of this practice in terms of neonatal pain and parental anxiety.
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1667
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Barbadoro P, Marigliano A, Savini S, D'Errico MM, Prospero E. Group B Streptococcal sepsis: an old or ongoing threat? Am J Infect Control 2011; 39:e45-e48. [PMID: 21704424 DOI: 10.1016/j.ajic.2010.12.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 12/20/2010] [Accepted: 12/20/2010] [Indexed: 11/18/2022]
Abstract
BACKGROUND Group B Streptococcus (GBS) is a major cause of severe infections in newborns. Early-onset disease (EOD) occurs within the first week of life, and it is usually vertically transmitted. In late-onset disease (LOD), pathogens may also come from nosocomial sources. We report 3 cases of GBS infection in very low birth weight infants hospitalized by a neonatal intensive care unit (NICU) in Italy. METHODS The cluster was identified thanks to an active surveillance program; an epidemiologic investigation took place. Pulsed-field gel electrophoresis (PFGE) was used to assess the clonal relatedness of strains. An audit to stress the adherence to isolation precautions and hand hygiene was organized. RESULTS During a 16-day period, 2 preterm newborns developed GBS LOD; an earlier case of GBS EOD occurred in a baby hospitalized by the same ward. The 3 GBS strains had the same antibiotic susceptibility pattern. The PFGE profiles of the 2 cases of LOD are indistinguishable from each other and closely related with the case of EOD. Strict infection control measures were adopted. CONCLUSION The implementation of additional infection control measures was able to stop the diffusion of infection; however, clusters like this should remind us the ongoing threat of GBS for the small NICU patients.
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MESH Headings
- Adult
- Age of Onset
- Bacteremia
- Cross Infection/diagnosis
- Cross Infection/epidemiology
- Cross Infection/microbiology
- Cross Infection/transmission
- Electrophoresis, Gel, Pulsed-Field
- Female
- Humans
- Incidence
- Infant, Newborn
- Infant, Premature
- Infant, Premature, Diseases/diagnosis
- Infant, Premature, Diseases/epidemiology
- Infant, Premature, Diseases/microbiology
- Infant, Very Low Birth Weight
- Infection Control
- Infectious Disease Transmission, Vertical
- Intensive Care Units, Neonatal
- Italy
- Sepsis/diagnosis
- Sepsis/epidemiology
- Sepsis/microbiology
- Sepsis/transmission
- Streptococcal Infections/diagnosis
- Streptococcal Infections/epidemiology
- Streptococcal Infections/microbiology
- Streptococcal Infections/transmission
- Streptococcus agalactiae/classification
- Streptococcus agalactiae/genetics
- Streptococcus agalactiae/isolation & purification
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Affiliation(s)
- Pamela Barbadoro
- Department of Biomedical Science, Section of Hygiene, Polytechnic University of the Marches, Ancona, Italy; Hospital Hygiene Service, AOU Ospedali Riuniti Ancona, Ancona, Italy.
| | - Anna Marigliano
- Department of Biomedical Science, Section of Hygiene, Polytechnic University of the Marches, Ancona, Italy
| | - Sandra Savini
- Hospital Hygiene Service, AOU Ospedali Riuniti Ancona, Ancona, Italy
| | - Marcello Mario D'Errico
- Department of Biomedical Science, Section of Hygiene, Polytechnic University of the Marches, Ancona, Italy; Hospital Hygiene Service, AOU Ospedali Riuniti Ancona, Ancona, Italy
| | - Emilia Prospero
- Department of Biomedical Science, Section of Hygiene, Polytechnic University of the Marches, Ancona, Italy; Hospital Hygiene Service, AOU Ospedali Riuniti Ancona, Ancona, Italy
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1668
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Sosnowski P, Krauss H, Bogdanski P, Suliburska J, Jablecka A, Cieslewicz A, Pupek-Musialik D, Jastak R. The influence of short-term L-arginine supplementation on rats' muscular and hepatic cells in ischemia-reperfusion syndrome. J Physiol Biochem 2011; 68:1-9. [PMID: 21948185 DOI: 10.1007/s13105-011-0111-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 08/30/2011] [Indexed: 12/17/2022]
Abstract
Due to the complex mechanisms of L-arginine activity, it is difficult to determine the clinical significance of supplementation with this amino acid. The objective of this study was to determine the influence of short-term supplementation with L-arginine in stress conditions, induced by ischemia-reperfusion syndrome, by assessing the damage to muscular and hepatic cells on the basis of creatine kinase (CK), alanine aminotransferase (ALAT) and aspartic aminotransferase (AspAT) activity in blood and the level of oxygen free radicals in analyzed tissues of rats. We observed that induced ischemia of hind limb caused an increase in CK, ALAT and AspAT activity and an increase in the level of free radicals in liver, but not in skeletal muscle. Supplementation with L-arginine led to a reduction in serum activity of CK and AspAT and reduction of the level of free radicals in analysed tissues. Simultaneous supplementation with L -arginine AND L-NAME resulted in a reversal of changes induced by L-arginine supplementation in the case of AspAT and free radicals in skeletal muscle. The results indicate that under conditions of ischemia-reperfusion, short-term administration of L-arginine has a protective effect on skeletal muscle manifesting itself by reduction of CK in the serum and reduction of free radicals level in THIS tissue.
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Affiliation(s)
- Przemysław Sosnowski
- Department of Physiology, Poznan University of Medical Sciences, Swiecickiego 6 Str., 60-781 Poznan, Poland
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1669
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Banerjee A, Kim BJ, Carmona EM, Cutting AS, Gurney MA, Carlos C, Feuer R, Prasadarao NV, Doran KS. Bacterial Pili exploit integrin machinery to promote immune activation and efficient blood-brain barrier penetration. Nat Commun 2011; 2:462. [PMID: 21897373 PMCID: PMC3195231 DOI: 10.1038/ncomms1474] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 08/10/2011] [Indexed: 12/25/2022] Open
Abstract
Group B Streptococcus (GBS) is the leading cause of meningitis in newborn infants. Bacterial cell surface appendages, known as pili, have been recently described in streptococcal pathogens, including GBS. The pilus tip adhesin, PilA, contributes to GBS adherence to blood-brain barrier (BBB) endothelium; however, the host receptor and the contribution of PilA in central nervous system (CNS) disease pathogenesis are unknown. Here we show that PilA binds collagen, which promotes GBS interaction with the α₂β₁ integrin resulting in activation of host chemokine expression and neutrophil recruitment during infection. Mice infected with the PilA-deficient mutant exhibit delayed mortality, a decrease in neutrophil infiltration and bacterial CNS dissemination. We find that PilA-mediated virulence is dependent on neutrophil influx as neutrophil depletion results in a decrease in BBB permeability and GBS-BBB penetration. Our results suggest that the bacterial pilus, specifically the PilA adhesin, has a dual role in immune activation and bacterial entry into the CNS.
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Affiliation(s)
- Anirban Banerjee
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
| | - Brandon J. Kim
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
- These authors contributed equally to this work
| | - Ellese M. Carmona
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
- These authors contributed equally to this work
| | - Andrew S. Cutting
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
| | - Michael A. Gurney
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
| | - Chris Carlos
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
| | - Ralph Feuer
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
| | - Nemani V. Prasadarao
- Division of Infectious Diseases, Department of Pediatrics, Childrens Hospital Los Angeles and University of Southern California Keck School of Medicine, Los Angeles, California 90027, USA
| | - Kelly S. Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University, 5500 Campanile Drive, San Diego, California 92182, USA
- Department of Pediatrics, University of California–San Diego School of Medicine, La Jolla, California 92093, USA
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1670
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Workman JL, Weber MD, Nelson RJ. Dietary arginine depletion reduces depressive-like responses in male, but not female, mice. Behav Brain Res 2011; 223:81-7. [DOI: 10.1016/j.bbr.2011.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 04/06/2011] [Accepted: 04/10/2011] [Indexed: 01/12/2023]
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1671
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Khare B, Krishnan V, Rajashankar KR, I-Hsiu H, Xin M, Ton-That H, Narayana SV. Structural differences between the Streptococcus agalactiae housekeeping and pilus-specific sortases: SrtA and SrtC1. PLoS One 2011; 6:e22995. [PMID: 21912586 PMCID: PMC3166054 DOI: 10.1371/journal.pone.0022995] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 07/06/2011] [Indexed: 11/19/2022] Open
Abstract
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.
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Affiliation(s)
- B. Khare
- Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - V. Krishnan
- Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - K. R. Rajashankar
- NE-CAT, Advanced Photon Source, Argonne National Laboratory, Chicago, Illinois, United States of America
| | - H. I-Hsiu
- University of Texas Health Science Center, Houston, Texas, United States of America
| | - M. Xin
- University of Texas Health Science Center, Houston, Texas, United States of America
| | - H. Ton-That
- University of Texas Health Science Center, Houston, Texas, United States of America
| | - S. V. Narayana
- Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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1672
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Martins ER, Andreu A, Correia P, Juncosa T, Bosch J, Ramirez M, Melo-Cristino J. Group B streptococci causing neonatal infections in barcelona are a stable clonal population: 18-year surveillance. J Clin Microbiol 2011; 49:2911-8. [PMID: 21697333 PMCID: PMC3147731 DOI: 10.1128/jcm.00271-11] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 06/04/2011] [Indexed: 11/20/2022] Open
Abstract
We analyzed 212 group B streptococci (GBS) from newborns with invasive infections in the area of Barcelona, Spain, between 1992 and 2009, with the aim of documenting changes in the prevalences of serotypes, antimicrobial resistance, and genetic lineages and evaluating their associations with either early-onset disease (EOD) or late-onset disease (LOD). Serotypes III (n = 118) and Ia (n = 47) together accounted for nearly 78% of the isolates. All isolates carried an alpha or alpha-like protein gene, and specific associations between genes and serotypes, such as serotype Ib and bca, serotype II and bca, serotype III and rib, and serotype V and alp3, reflected the presence of particular genetic lineages. Macrolide resistance (14.2%) was significantly associated with serotype V. Pulsed-field gel electrophoresis (PFGE) clustering was an excellent predictor of serotype and antibiotic resistance. The combination of PFGE and multilocus sequence typing revealed a large number of genetically distinct lineages. Still, specific lineages were dominant in our collection, particularly the serotype III/ST17/rib lineage, which had enhanced potential to cause LOD. Serotype Ia was concentrated in a single PFGE cluster composed of two genetic lineages: ST23/eps and ST24/bca. The ST24/bca sublineage of serotype Ia, which is found infrequently elsewhere, may be emerging as an important cause of neonatal invasive infections in the Mediterranean region. In spite of the introduction of prophylaxis, resulting in a pronounced decline in the frequency of EOD, the study revealed a remarkably stable clonal structure of GBS causing neonatal infections in Barcelona over a period of 18 years.
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Affiliation(s)
- E. R. Martins
- Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - A. Andreu
- Servei de Microbiología, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona
| | - P. Correia
- Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - T. Juncosa
- Servei de Microbiología, Hospital Sant Joan de Deu, Esplugues de Llobregat
| | - J. Bosch
- Servei de Microbiología, Hospital Clínic i Provincial, Barcelona, Spain
| | - M. Ramirez
- Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - J. Melo-Cristino
- Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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1673
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Morales P, Bustamante D, Espina-Marchant P, Neira-Peña T, Gutiérrez-Hernández MA, Allende-Castro C, Rojas-Mancilla E. Pathophysiology of perinatal asphyxia: can we predict and improve individual outcomes? EPMA J 2011. [PMID: 23199150 PMCID: PMC3405380 DOI: 10.1007/s13167-011-0100-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Perinatal asphyxia occurs still with great incidence whenever delivery is prolonged, despite improvements in perinatal care. After asphyxia, infants can suffer from short- to long-term neurological sequelae, their severity depend upon the extent of the insult, the metabolic imbalance during the re-oxygenation period and the developmental state of the affected regions. Significant progresses in understanding of perinatal asphyxia pathophysiology have achieved. However, predictive diagnostics and personalised therapeutic interventions are still under initial development. Now the emphasis is on early non-invasive diagnosis approach, as well as, in identifying new therapeutic targets to improve individual outcomes. In this review we discuss (i) specific biomarkers for early prediction of perinatal asphyxia outcome; (ii) short and long term sequelae; (iii) neurocircuitries involved; (iv) molecular pathways; (v) neuroinflammation systems; (vi) endogenous brain rescue systems, including activation of sentinel proteins and neurogenesis; and (vii) therapeutic targets for preventing or mitigating the effects produced by asphyxia.
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Affiliation(s)
- Paola Morales
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Diego Bustamante
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Pablo Espina-Marchant
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Tanya Neira-Peña
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Manuel A. Gutiérrez-Hernández
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Camilo Allende-Castro
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
| | - Edgardo Rojas-Mancilla
- Programme of Molecular & Clinical Pharmacology, ICBM, Medical Faculty, University of Chile, PO Box 70.000, Santiago 7, Chile
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1674
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Berardi A, Lugli L, Rossi C, China M, Chiossi C, Gambini L, Guidi B, Pedna MF, Piepoli M, Simoni A, Ferrari F. Intrapartum antibiotic prophylaxis failure and group-B streptococcus early-onset disease. J Matern Fetal Neonatal Med 2011; 24:1221-4. [PMID: 21714691 DOI: 10.3109/14767058.2011.552652] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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1675
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Bagnoli F, Baudner B, Mishra RPN, Bartolini E, Fiaschi L, Mariotti P, Nardi-Dei V, Boucher P, Rappuoli R. Designing the next generation of vaccines for global public health. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2011; 15:545-66. [PMID: 21682594 DOI: 10.1089/omi.2010.0127] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Vaccine research and development are experiencing a renaissance of interest from the global scientific community. There are four major reasons for this: (1) the lack of efficacious treatment for many devastating infections; (2) the emergence of multidrug resistant bacteria; (3) the need for improving the safety of the more traditional licensed vaccines; and finally, (4) the great promise for innovative vaccine design and research with convergence of omics sciences, such as genomics, proteomics, immunomics, and vaccinology. Our first project based on omics was initiated in 2000 and was termed reverse vaccinology. At that time, antigen identification was mainly based on bioinformatic analysis of a singular genome. Since then, omics-guided approaches have been applied to its full potential in several proof-of-concept studies in the industry, with the first reverse vaccinology-derived vaccine now in late stage clinical trials and several vaccines developed by omics in preclinical studies. In the meantime, vaccine discovery and development has been further improved with the support of proteomics, functional genomics, comparative genomics, structural biology, and most recently vaccinomics. We illustrate in this review how omics biotechnologies and integrative biology are expected to accelerate the identification of vaccine candidates against difficult pathogens for which traditional vaccine development has thus far been failing, and how research will provide safer vaccines and improved formulations for immunocompromised patients in the near future. Finally, we present a discussion to situate omics-guided rational vaccine design in the broader context of global public health and how it can benefit citizens in both developed and developing countries.
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1676
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Abstract
Knowledge of the nature, prognosis, and ways to treat brain lesions in neonatal infants has increased remarkably. Neonatal hypoxic-ischaemic encephalopathy (HIE) in term infants, mirrors a progressive cascade of excito-oxidative events that unfold in the brain after an asphyxial insult. In the laboratory, this cascade can be blocked to protect brain tissue through the process of neuroprotection. However, proof of a clinical effect was lacking until the publication of three positive randomised controlled trials of moderate hypothermia for term infants with HIE. These results have greatly improved treatment prospects for babies with asphyxia and altered understanding of the theory of neuroprotection. The studies show that moderate hypothermia within 6 h of asphyxia improves survival without cerebral palsy or other disability by about 40% and reduces death or neurological disability by nearly 30%. The search is on to discover adjuvant treatments that can further enhance the effects of hypothermia.
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1677
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Melin P. Neonatal group B streptococcal disease: from pathogenesis to preventive strategies. Clin Microbiol Infect 2011; 17:1294-303. [PMID: 21672083 DOI: 10.1111/j.1469-0691.2011.03576.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Streptococcus agalactiae, or group B streptococcus (GBS), remains the leading cause of neonatal sepsis and meningitis, as early-onset or late-onset diseases (EOD, LOD). Where consensus guidelines to detect and treat intrapartum women with GBS colonization have been widely adopted, incidence of neonatal EOD has dramatically declined. In response to both successful impacts on the incidence of GBS-EOD and analyses of missed opportunities, the first American guidelines for prevention issued in the 1990s have since been adapted in several stages to improve their efficacy. In some countries in Europe, nationwide guidelines, whether screening-based or risk-based, for the prevention of neonatal GBS diseases have also been issued and adopted, with the expected impact on incidence of GBS-EOD. In spite of universal screening, in spite of the great progress that has been made, GBS-EOD continues to occur and the GBS burden remains a significant public health issue. Continuous efforts to improve screening for GBS status continue to be important and may be able to take advantage of new rapid diagnostic technologies. The current screening-based strategy for prevention is highly effective but imperfect. Given the challenges, limitations and potential complications of maternal intrapartum prophylaxis, a new approach is still needed. Maternal immunization against GBS is an attractive alternative for the prevention of not only neonatal diseases but also stillbirths and maternal diseases. Vaccines against GBS may become the most effective and sustainable long-term preventive strategy.
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Affiliation(s)
- P Melin
- National Reference Centre for Group B Streptococci, Medical Microbiology Department, University Hospital of Liege, Liege, Belgium.
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1678
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Structural vaccinology to thwart antigenic variation in microbial pathogens. Proc Natl Acad Sci U S A 2011; 108:10029-30. [PMID: 21670300 DOI: 10.1073/pnas.1107324108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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1679
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Creti R, Imperi M, Pataracchia M, Alfarone G, Recchia S, Baldassarri L. Identification and molecular characterization of a S. agalactiae strain lacking the capsular locus. Eur J Clin Microbiol Infect Dis 2011; 31:233-5. [PMID: 21614482 DOI: 10.1007/s10096-011-1298-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 05/11/2011] [Indexed: 10/18/2022]
Abstract
During a national surveillance program on Group B streptococci (GBS) maternal carriage and neonatal infections, a GBS strain isolated from a pregnant woman's vagino-rectal swab was non typable by either serological or molecular methods. Further molecular characterization demonstrated that the strain lacked the entire capsular locus, possibly by a recombination event that excised a 14,1 Kbase pairs genomic fragment extending from the regulatory protein cpsX gene to the neuA gene. The natural loss of the capsular locus by GBS isolated from a human has never been described so far. Such an event, while possibly a dead-end from the evolutionary point of view, leaves a still able-to-colonize organism unrecognizable by the vaccines currently under development.
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Affiliation(s)
- R Creti
- Reparto di Malattie Batteriche Respiratorie e Sistemiche-Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161, Rome, Italy.
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1680
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Vadillo-Ortega F, Perichart-Perera O, Espino S, Avila-Vergara MA, Ibarra I, Ahued R, Godines M, Parry S, Macones G, Strauss JF. Effect of supplementation during pregnancy with L-arginine and antioxidant vitamins in medical food on pre-eclampsia in high risk population: randomised controlled trial. BMJ 2011; 342:d2901. [PMID: 21596735 PMCID: PMC3100912 DOI: 10.1136/bmj.d2901] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To test the hypothesis that a relative deficiency in L-arginine, the substrate for synthesis of the vasodilatory gas nitric oxide, may be associated with the development of pre-eclampsia in a population at high risk. DESIGN Randomised, blinded, placebo controlled clinical trial. SETTING Tertiary public hospital in Mexico City. PARTICIPANTS Pregnant women with a history of a previous pregnancy complicated by pre-eclampsia, or pre-eclampsia in a first degree relative, and deemed to be at increased risk of recurrence of the disease were studied from week 14-32 of gestation and followed until delivery. INTERVENTIONS Supplementation with a medical food-bars containing L-arginine plus antioxidant vitamins, antioxidant vitamins alone, or placebo-during pregnancy. MAIN OUTCOME MEASURE Development of pre-eclampsia/eclampsia. RESULTS 222 women were allocated to the placebo group, 228 received L-arginine plus antioxidant vitamins, and 222 received antioxidant vitamins alone. Women had 4-8 prenatal visits while receiving the bars. The incidence of pre-eclampsia was reduced significantly (χ(2) = 19.41; P < 0.001) in women randomised to L-arginine plus antioxidant vitamins compared with placebo (absolute risk reduction 0.17 (95% confidence interval 0.12 to 0.21). Antioxidant vitamins alone showed an observed benefit, but this effect was not statistically significant compared with placebo (χ(2) = 3.76; P = 0.052; absolute risk reduction 0.07, 0.005 to 0.15). L-arginine plus antioxidant vitamins compared with antioxidant vitamins alone resulted in a significant effect (P = 0.004; absolute risk reduction 0.09, 0.05 to 0.14). CONCLUSIONS Supplementation during pregnancy with a medical food containing L-arginine and antioxidant vitamins reduced the incidence of pre-eclampsia in a population at high risk of the condition. Antioxidant vitamins alone did not have a protective effect for prevention of pre-eclampsia. Supplementation with L-arginine plus antioxidant vitamins needs to be evaluated in a low risk population to determine the generalisability of the protective effect, and the relative contributions of L-arginine and antioxidant vitamins to the observed effects of the combined treatment need to be determined. Trial registration Clinical trials NCT00469846.
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Affiliation(s)
- Felipe Vadillo-Ortega
- Department of Experimental Medicine, School of Medicine, Universidad Nacional, Autonoma de Mexico, Torre de Investigacion, 3er Piso, Ciudad Universitaria, Mexico, DF 04510.
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1681
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Structure-based approach to rationally design a chimeric protein for an effective vaccine against Group B Streptococcus infections. Proc Natl Acad Sci U S A 2011; 108:10278-83. [PMID: 21593422 DOI: 10.1073/pnas.1106590108] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Structural vaccinology is an emerging strategy for the rational design of vaccine candidates. We successfully applied structural vaccinology to design a fully synthetic protein with multivalent protection activity. In Group B Streptococcus, cell-surface pili have aroused great interest because of their direct roles in virulence and importance as protective antigens. The backbone subunit of type 2a pilus (BP-2a) is present in six immunogenically different but structurally similar variants. We determined the 3D structure of one of the variants, and experimentally demonstrated that protective antibodies specifically recognize one of the four domains that comprise the protein. We therefore constructed a synthetic protein constituted by the protective domain of each one of the six variants and showed that the chimeric protein protects mice against the challenge with all of the type 2a pilus-carrying strains. This work demonstrates the power of structural vaccinology and will facilitate the development of an optimized, broadly protective pilus-based vaccine against Group B Streptococcus by combining the uniquely generated chimeric protein with protective pilin subunits from two other previously identified pilus types. In addition, this work describes a template procedure that can be followed to develop vaccines against other bacterial pathogens.
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1682
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Senn BM, Visram Z, Meinke AL, Neubauer C, Gelbmann D, Sinzinger J, Hanner M, Lundberg U, Boisvert H, Reinscheid D, von Gabain A, Nagy E. Monoclonal antibodies targeting different cell wall antigens of group B streptococcus mediate protection in both Fc-dependent and independent manner. Vaccine 2011; 29:4116-24. [DOI: 10.1016/j.vaccine.2011.03.100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Revised: 03/20/2011] [Accepted: 03/28/2011] [Indexed: 10/18/2022]
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1683
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Hendrickx APA, Budzik JM, Oh SY, Schneewind O. Architects at the bacterial surface - sortases and the assembly of pili with isopeptide bonds. Nat Rev Microbiol 2011; 9:166-76. [PMID: 21326273 DOI: 10.1038/nrmicro2520] [Citation(s) in RCA: 195] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The cell wall envelope of Gram-positive bacteria can be thought of as a surface organelle for the assembly of macromolecular structures that enable the unique lifestyle of each microorganism. Sortases - enzymes that cleave the sorting signals of secreted proteins to form isopeptide (amide) bonds between the secreted proteins and peptidoglycan or polypeptides - function as the principal architects of the bacterial surface. Acting alone or with other sortase enzymes, sortase construction leads to the anchoring of surface proteins at specific sites in the envelope or to the assembly of pili, which are fibrous structures formed from many protein subunits. The catalysis of intermolecular isopeptide bonds between pilin subunits is intertwined with the assembly of intramolecular isopeptide bonds within pilin subunits. Together, these isopeptide bonds endow these sortase products with adhesive properties and resistance to host proteases.
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Affiliation(s)
- Antoni P A Hendrickx
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, Illinois 60637, USA
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1684
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Sillanpää J, Nallapareddy SR, Singh KV, Prakash VP, Fothergill T, Ton-That H, Murray BE. Characterization of the ebp(fm) pilus-encoding operon of Enterococcus faecium and its role in biofilm formation and virulence in a murine model of urinary tract infection. Virulence 2011; 1:236-46. [PMID: 20676385 DOI: 10.4161/viru.1.4.11966] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We recently identified 15 genes encoding putative surface proteins with features of MSCRAMMs and/or pili in the Enterococcus faecium TX0016 (DO) genome, including four predicted pilus-encoding gene clusters; we also demonstrated that one of these, ebpABC(fm), is transcribed as an operon, that its putative major pilus subunit, EbpC(fm) (also called pilB), is polymerized into high molecular weight complexes, and that it is enriched among clinical E. faecium isolates. Here, we created a deletion of the ebpABC(fm) operon in an endocarditis-derived E. faecium strain (TX82) and showed, by a combination of whole-cell ELISA, flow cytometry, immunoblot and immunogold electron microscopy, that this deletion abolished EbpC(fm) expression and eliminated EbpC(fm)-containing pili from the cell surface. However, transcription of the downstream sortase, bps(fm), was not affected. Importantly, the ebpABC(fm) deletion resulted in significantly reduced biofilm formation (p < 0.0001) and initial adherence (p < 0.0001) versus the wild-type; both were restored by complementing ebpABC(fm) in trans, which also restored cell surface expression of EbpC(fm) and pilus production. Furthermore, the deletion mutant was significantly attenuated in two independent mixed infection mouse urinary tract experiments, i.e., outnumbered by the wild-type in kidneys (p = 0.0003 and < 0.0001, respectively) and urinary bladders (p = 0.0003 and = 0.002). In conclusion, we have shown that the ebpABC(fm) locus encodes pili on the E. faecium TX82 cell surface and provide the first evidence that pili of this emerging pathogen are important for its ability to form biofilm and to cause infection in an ascending UTI model.
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Affiliation(s)
- Jouko Sillanpää
- Department of Internal Medicine, and Center for the Study of Emerging and Re-emerging Pathogens, Division of Infectious Diseases, University of Texas Medical School at Houston, Houston, TX, USA
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1685
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Papasergi S, Brega S, Mistou MY, Firon A, Oxaran V, Dover R, Teti G, Shai Y, Trieu-Cuot P, Dramsi S. The GBS PI-2a pilus is required for virulence in mice neonates. PLoS One 2011; 6:e18747. [PMID: 21525979 PMCID: PMC3078112 DOI: 10.1371/journal.pone.0018747] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 03/10/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND 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. METHODOLOGY/PRINCIPAL FINDINGS 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. CONCLUSIONS/SIGNIFICANCE 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 context.
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Affiliation(s)
- Salvatore Papasergi
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France
- URA CNRS 2172, Paris, France
- The Elie Metchnikoff Deparment, University of Messina, Messina, Italy
| | - Sara Brega
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France
- URA CNRS 2172, Paris, France
| | - Michel-Yves Mistou
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France
- URA CNRS 2172, Paris, France
- INRA, MICALIS UMR 1319, Equipe Paroi, Jouy-en-Josas, France
| | - Arnaud Firon
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France
- URA CNRS 2172, Paris, France
| | - Virginie Oxaran
- INRA, MICALIS UMR1319, Equipe Protéines de Surface Utiles, Jouy-en-Josas, France
| | - Ron Dover
- Depatment of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Giuseppe Teti
- The Elie Metchnikoff Deparment, University of Messina, Messina, Italy
| | - Yechiel Shai
- Depatment of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Patrick Trieu-Cuot
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France
- URA CNRS 2172, Paris, France
| | - Shaynoor Dramsi
- Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, Paris, France
- URA CNRS 2172, Paris, France
- * E-mail:
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1686
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Lancaster L, Saydam M, Markey K, Ho MM, Mawas F. Immunogenicity and physico-chemical characterisation of a candidate conjugate vaccine against group B streptococcus serotypes Ia, Ib and III. Vaccine 2011; 29:3213-21. [DOI: 10.1016/j.vaccine.2011.02.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 02/12/2011] [Indexed: 10/18/2022]
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1687
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Gentile MA, Melchiorre S, Emolo C, Moschioni M, Gianfaldoni C, Pancotto L, Ferlenghi I, Scarselli M, Pansegrau W, Veggi D, Merola M, Cantini F, Ruggiero P, Banci L, Masignani V. Structural and functional characterization of the Streptococcus pneumoniae RrgB pilus backbone D1 domain. J Biol Chem 2011; 286:14588-97. [PMID: 21367860 DOI: 10.1074/jbc.m110.202739] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Streptococcus pneumoniae expresses on its surface adhesive pili, involved in bacterial attachment to epithelial cells and virulence. The pneumococcal pilus is composed of three proteins, RrgA, RrgB, and RrgC, each stabilized by intramolecular isopeptide bonds and covalently polymerized by means of intermolecular isopeptide bonds to form an extended fiber. RrgB is the pilus scaffold subunit and is protective in vivo in mouse models of sepsis and pneumonia, thus representing a potential vaccine candidate. The crystal structure of a major RrgB C-terminal portion featured an organization into three independently folded protein domains (D2-D4), whereas the N-terminal D1 domain (D1) remained unsolved. We have tested the four single recombinant RrgB domains in active and passive immunization studies and show that D1 is the most effective, providing a level of protection comparable with that of the full-length protein. To elucidate the structural features of D1, we solved the solution structure of the recombinant domain by NMR spectroscopy. The spectra analysis revealed that D1 has many flexible regions, does not contain any intramolecular isopeptide bond, and shares with the other domains an Ig-like fold. In addition, we demonstrated, by site-directed mutagenesis and complementation in S. pneumoniae, that the D1 domain contains the Lys residue (Lys-183) involved in the formation of the intermolecular isopeptide bonds and pilus polymerization. Finally, we present a model of the RrgB protein architecture along with the mapping of two surface-exposed linear epitopes recognized by protective antisera.
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1688
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Cozzi R, Malito E, Nuccitelli A, D'Onofrio M, Martinelli M, Ferlenghi I, Grandi G, Telford JL, Maione D, Rinaudo CD. Structure analysis and site-directed mutagenesis of defined key residues and motives for pilus-related sortase C1 in group B Streptococcus. FASEB J 2011; 25:1874-86. [PMID: 21357525 DOI: 10.1096/fj.10-174797] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In group B Streptococcus (GBS), 3 structurally distinct types of pili have been discovered as potential virulence factors and vaccine candidates. The pilus-forming proteins are assembled into high-molecular-weight polymers via a transpeptidation mechanism mediated by specific class C sortases. Using a multidisciplinary approach including bioinformatics, structural and biochemical studies, and in vivo mutagenesis, we performed a broad characterization of GBS sortase C1 of pilus island 2a. The high-resolution X-ray structure of the enzyme revealed that the active site, into the β-barrel core of the enzyme, is made of the catalytic triad His157-Cys219-Arg228 and covered by a loop, known as the "lid." We show that the catalytic triad and the predicted N- and C-terminal transmembrane regions are required for the enzyme activity. Interestingly, by in vivo complementation mutagenesis studies, we found that the deletion of the entire lid loop or mutations in specific lid key residues had no effect on catalytic activity of the enzyme. In addition, kinetic characterizations of recombinant enzymes indicate that the lid mutants can still recognize and cleave the substrate-mimicking peptide at least as well as the wild-type protein.
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Affiliation(s)
- Roberta Cozzi
- Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy
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1689
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Mertes PM, Karila C, Demoly P, Auroy Y, Ponvert C, Lucas MM, Malinovsky JM. [What is the reality of anaphylactoid reactions during anaesthesia? Classification, prevalence, clinical features, drugs involved and morbidity and mortality]. ACTA ACUST UNITED AC 2011; 30:223-39. [PMID: 21353759 DOI: 10.1016/j.annfar.2011.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- P-M Mertes
- Service d'anesthésie-réanimation chirurgicale, hôpital Central, CHU de Nancy, 29 avenue de Lattre-de-Tassigny, Nancy cedex, France.
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1690
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Vengadesan K, Ma X, Dwivedi P, Ton-That H, Narayana SVL. A model for group B Streptococcus pilus type 1: the structure of a 35-kDa C-terminal fragment of the major pilin GBS80. J Mol Biol 2011; 407:731-43. [PMID: 21333654 DOI: 10.1016/j.jmb.2011.02.024] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 02/09/2011] [Accepted: 02/10/2011] [Indexed: 10/18/2022]
Abstract
The Gram-positive pathogen Streptococcus agalactiae, known as group B Streptococcus (GBS), is the leading cause of bacterial septicemia, pneumonia, and meningitis among neonates. GBS assembles two types of pili-pilus islands (PIs) 1 and 2-on its surface to adhere to host cells and to initiate colonization for pathogenesis. The GBS PI-1 pilus is made of one major pilin, GBS80, which forms the pilus shaft, and two secondary pilins, GBS104 and GBS52, which are incorporated into the pilus at various places. We report here the crystal structure of the 35-kDa C-terminal fragment from GBS80, which is composed of two IgG-like domains (N2-N3). The structure was solved by single-wavelength anomalous dispersion using sodium-iodide-soaked crystals and diffraction data collected at the home source. The N2 domain exhibits a cnaA/DEv-IgG fold with two calcium-binding sites, while the N3 domain displays a cnaB/IgG-rev fold. We have built a model for full-length GBS80 (N1, N2, and N3) with the help of available homologous major pilin structures, and we propose a model for the GBS PI-1 pilus shaft. The N2 and N3 domains are arranged in tandem along the pilus shaft, whereas the respective N1 domain is tilted by approximately 20° away from the pilus axis. We have also identified a pilin-like motif in the minor pilin GBS52, which might aid its incorporation at the pilus base.
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Affiliation(s)
- Krishnan Vengadesan
- Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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1691
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Boralevi F. [What's new in paediatric dermatology?]. Ann Dermatol Venereol 2011; 137 Suppl 4:S145-57. [PMID: 21193118 DOI: 10.1016/s0151-9638(10)70041-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This paper summarizes a review of the medical literature focused on the field of pediatric dermatology from December 2009 to November 2010. Our objective was to select the papers published in the main journals of dermatology, internal medicine, pediatrics, infectious diseases and allergy that bring new information and significant advances concerning skin diseases in children. Recent advances in the field of infantile hemangiomas and atopic dermatitis are particularly detailed. This review also covers the main the following topics: psoriasis, Kawasaki disease, head lice and warts management, lichen, rare diseases such as epidermolyses bullosae.
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Affiliation(s)
- F Boralevi
- Unité de dermatologie pédiatrique, Hôpital Pellegrin-enfant, Place Amélie Raba-Léon, 33076 Bordeaux cedex, France.
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1692
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Congenital Syphilis Like Many Years Ago. Case Rep Infect Dis 2011; 2011:235059. [PMID: 22567464 PMCID: PMC3336237 DOI: 10.1155/2011/235059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 07/25/2011] [Indexed: 11/17/2022] Open
Abstract
This case concerns a premature infant with typical signs of congenital syphilis born to an untreated foreign mother.
Syphilis prevalence in pregnant women has been rising in Italy since the beginning of the 21st century, mainly due to immigration.
A correct antenatal syphilis screening and consequent adequate therapy of pregnant woman are fundamental to prevent the neonatal infection.
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1693
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Reiss A, Braun JS, Jäger K, Freyer D, Laube G, Bührer C, Felderhoff-Müser U, Stadelmann C, Nizet V, Weber JR. Bacterial pore-forming cytolysins induce neuronal damage in a rat model of neonatal meningitis. J Infect Dis 2010; 203:393-400. [PMID: 21186256 DOI: 10.1093/infdis/jiq047] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Group B Streptococcus (GBS) and Streptococcus pneumoniae (SP) are leading causes of bacterial meningitis in neonates and children. Each pathogen produces a pore-forming cytolytic toxin, β-hemolysin/cytolysin (β-h/c) by GBS and pneumolysin by SP. The aim of this study was to understand the role of these pore-forming cytotoxins, in particular of the GBS β-h/c, as potential neurotoxins in experimental neonatal meningitis. METHODS Meningitis was induced in 7- and 11-day-old rats by intracisternal injection of wild type (WT) GBS or SP and compared with isogenic β-h/c- or pneumolysin-deficient mutants, or a double mutant of SP deficient in pneumolysin and hydrogen peroxide production. RESULTS GBS β-h/c and SP pneumolysin contributed to neuronal damage, worsened clinical outcome and weight loss, but had no influence on the early kinetics of leukocyte influx and bacterial growth in the cerebrospinal fluid. In vitro, β-h/c-induced neuronal apoptosis occurred independently of caspase-activation and was not preventable by the broad spectrum caspase-inhibitor z-VAD-fmk. CONCLUSIONS These data suggest that both cytolytic toxins, the GBS β-h/c and SP pneumolysin, contribute to neuronal damage in meningitis and extend the concept of a key role for bacterial pore-forming cytolysins in the pathogenesis and sequelae of neonatal meningitis.
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Affiliation(s)
- Anja Reiss
- Department of Neonatology, Charité Universitätsmedizin Berlin, Berlin, Germany
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1694
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Meinke AL, Senn BM, Visram Z, Henics TZ, Minh DB, Schüler W, Neubauer C, Gelbmann D, Noiges B, Sinzinger J, Hanner M, Dewasthaly S, Lundberg U, Hordnes K, Masoud H, Sevelda P, von Gabain A, Nagy E. Immunological fingerprinting of group B streptococci: From circulating human antibodies to protective antigens. Vaccine 2010; 28:6997-7008. [DOI: 10.1016/j.vaccine.2010.08.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 08/03/2010] [Accepted: 08/06/2010] [Indexed: 11/25/2022]
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1695
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Progress in the development of effective vaccines to prevent selected gram-positive bacterial infections. Am J Med Sci 2010; 340:218-25. [PMID: 20697258 DOI: 10.1097/maj.0b013e3181e939ab] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Infections caused by virulent Gram-positive bacteria, such as Staphylococcus aureus, group B streptococci and group A streptococci, remain significant causes of morbidity and mortality despite progress in antimicrobial therapy. Despite significant advances in the understanding of the pathogenesis of infection caused by these organisms, there are only limited strategies to prevent infection. In this article, we review efforts to develop safe and effective vaccines that would prevent infections caused by these 3 pathogens.
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1696
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Abstract
Vaccines have saved the lives of millions of children and continue to be essential interventions to control infectious diseases among people of all ages. The list of recommended vaccines for children has expanded in recent years; however, many viral, bacterial and parasitic infections remain a major cause of morbidity and mortality in children. Improved vaccines to prevent Streptococcus pneumoniae and Neisseria meningitidis infections in children will soon be available. Recent scientific advances are being applied to design new childhood vaccines affording enhanced efficacy, safety and tolerability. Financial barriers and other obstacles to adequate vaccine access need to be eliminated to assure coverage for all children and adolescents.
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1697
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Berardi A, Rossi C, Biasini A, Minniti S, Venturelli C, Ferrari F, Facchinetti F. Efficacy of intrapartum chemoprophylaxis less than 4 hours duration. J Matern Fetal Neonatal Med 2010; 24:619-25. [PMID: 20828241 DOI: 10.3109/14767058.2010.511347] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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1698
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Kuhn P, Dheu C, Bolender C, Chognot D, Keller L, Demil H, Donato L, Langer B, Messer J, Astruc D. Incidence and distribution of pathogens in early-onset neonatal sepsis in the era of antenatal antibiotics. Paediatr Perinat Epidemiol 2010; 24:479-87. [PMID: 20670228 DOI: 10.1111/j.1365-3016.2010.01132.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In 2001 France issued a new set of guidelines for the use of antenatal antibiotics (AA). These guidelines recommended intrapartum antimicrobial prophylaxis (IAP) to prevent group B streptococcal (GBS) disease and AA to prolong pregnancy in the event of preterm premature rupture of membranes (AA for PPROM). This study aims to determine the effects of AA, recommended by national guidelines, on the incidence and distribution of pathogens in early-onset neonatal sepsis (EONS). We performed a population-based, prospective, observational study of level II and III perinatal centres throughout the region of Alsace, a northeastern area of France, between March 2004 and February 2005. The study population included all neonates with confirmed or probable EONS, who were treated with antibiotics for at least 5 days. We analysed exposure to AA, as well as clinical and microbiological data obtained from medical records. A total of 20 131 neonates were born during the study period, and 217 were included in the study. Of these, 24 subjects had confirmed sepsis, 140 had probable sepsis and 53 had possible EONS. The overall incidence of confirmed EONS was 1.19 per 1000 births. The infecting bacteria was GBS in 15 of 24 (62.5%) confirmed EONS cases (incidence: 0.75 per 1000 births) and in 81 of 140 (58%) probable sepsis cases. Escherichia coli was identified in 6 of 24 (25%) cases of confirmed EONS (incidence: 0.3 per 1000 births) and in 30 of 140 (21%) cases of clinical sepsis. Among E. coli infections (n= 36), amoxicillin resistance (n= 18) was statistically linked with AA use (P = 0.045). This link was significant in cases of PPROM (P = 0.015), but not when IAP was administered to prevent GBS disease (P = 0.264). IAP was not performed in 18 of 60 (30%) cases and 32 of 93 (34%) cases, despite positive screening or the presence of risk factors for EONS, respectively. Group B streptococcus remains the predominant pathogen in the era of AA. Aminopenicillin-resistant E. coli infections seem to be linked to prolonged AA in cases of PPROM and appear to preferentially affect preterm infants. Therefore, postnatal treatment strategies should consider this possible effect. Our data indicate that the current policy of GBS maternal prophylaxis is not associated with an excessive risk of pathogen resistance. Considering the high incidence of GBS EONS in our region, possible progress could result from better observance of guidelines. These results strengthen the need for continuation of surveillance.
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Affiliation(s)
- Pierre Kuhn
- Service de Pédiatrie 2, Hôpital de Hautepierre, Centre Hospitalier Universitaire de Strasbourg, Strasbourg, France.
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1699
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Emergence and global dissemination of host-specific Streptococcus agalactiae clones. mBio 2010; 1. [PMID: 20824105 PMCID: PMC2932510 DOI: 10.1128/mbio.00178-10] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 07/20/2010] [Indexed: 01/04/2023] Open
Abstract
To examine the global diversity of Streptococcus agalactiae (group B streptococci [GBS]) and to elucidate the evolutionary processes that determine its population genetics structure and the reported changes in host tropism and infection epidemiology, we examined a collection of 238 bovine and human isolates from nine countries on five continents. Phylogenetic analysis based on the sequences of 15 housekeeping genes combined with patterns of virulence-associated traits identified a genetically heterogeneous core population from which virulent lineages occasionally emerge as a result of recombination affecting major segments of the genome. Such lineages, like clonal complex 17 (CC17) and two distinct clusters of CC23, are exclusively adapted to either humans or cattle and successfully spread globally. The recent emergence and expansion of the human-associated and highly virulent sequence type 17 (ST17) could conceivably account, in part, for the increased prevalence of neonatal GBS infections after 1960. The composite structure of the S. agalactiae genome invalidates phylogenetic inferences exclusively based on multilocus sequence typing (MLST) data and thereby the previously reported conclusion that the human-associated CC17 emerged from the bovine-associated CC67. Group B streptococci (GBS) (Streptococcus agalactiae) have long been recognized as important causes of mastitis in cattle. After 1960, GBS also became the most prevalent cause of invasive and often fatal infections in newborns. At the same time, GBS are carried by a substantial proportion of healthy individuals. The aims of this study were to elucidate the genetic mechanisms that lead to diversification of the GBS population and to examine the relationship between virulence and host preference of evolutionary lineages of GBS. Genetic analysis of GBS isolates from worldwide sources demonstrated epidemic clones adapted specifically to either the human or bovine host. Such clones seem to emerge from a genetically heterogeneous core population as a result of recombination affecting major segments of the genome. Emergence and global spread of certain clones explain, in part, the change in epidemiology of GBS disease and may have implications for prevention.
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1700
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Granlund M, Axemo P, Bremme K, Bryngelsson AL, Carlsson Wallin M, Ekström CM, Håkansson S, Jacobsson B, Källén K, Spetz E, Tessin I. Antimicrobial resistance in colonizing group B Streptococci before the implementation of a Swedish intrapartum antibiotic prophylaxis program. Eur J Clin Microbiol Infect Dis 2010; 29:1195-201. [PMID: 20706855 DOI: 10.1007/s10096-010-0877-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2009] [Accepted: 01/05/2010] [Indexed: 11/27/2022]
Abstract
The prevalence of antibiotic resistance and their genetic determinants in colonizing group B streptococci (GBS) sampled in a Swedish nationwide survey was examined. In five GBS isolates (1.3%), kanamycin/amikacin resistance and the presence of the aphA-3 gene was identified. Three of these isolates carried the aad-6 gene and were streptomycin-resistant. Screening with kanamycin and streptomycin 1,000-μg disks enabled a rapid and easy detection of these isolates. In all, 312/396 (79%) GBS were tetracycline-resistant and 95% of the examined isolates harbored the tetM gene. Among the 22 (5.5%) GBS resistant to erythromycin and/or clindamycin, the ermB gene was detected in nine isolates (41%) and erm(A/TR) in ten isolates (45%). A high level of erythromycin and clindamycin resistance with minimum inhibitory concentrations (MICs) >256 mg/L was found in four serotype V isolates that harbored ermB. The erythromycin/clindamycin resistance was distributed among all of the common serotypes Ia, Ib, II, III, IV, and V, but was not present in any of the 44 serotype III isolates associated to clonal complex 17. Screening for penicillin resistance with 1-μg oxacillin disks showed a homogenous population with a mean inhibition zone of 20 mm. A change in the present oxacillin breakpoints for GBS is suggested.
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Affiliation(s)
- M Granlund
- Department of Clinical Bacteriology, Umeå University Hospital, 901 85 Umeå, Sweden.
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