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B Streptococcus (b + streptococcus)
Kinds of B Streptococcus Selected AbstractsIn Utero Ethanol Exposure Impairs Defenses Against Experimental Group B Streptococcus in the Term Guinea Pig LungALCOHOLISM, Issue 2 2009Theresa W. Gauthier Background:, The effects of fetal alcohol exposure on the risks of neonatal lung injury and infection remain under investigation. The resident alveolar macrophage (AM) is the first line of immune defense against pulmonary infections. In utero ethanol (ETOH) exposure deranges the function of both premature and term guinea pig AM. We hypothesized that fetal ETOH exposure would increase the risk of pulmonary infection in vivo. Methods:, We developed a novel in vivo model of group B Streptococcus (GBS) pneumonia using our established guinea pig model of fetal ETOH exposure. Timed-pregnant guinea pigs were pair fed ±ETOH and some were supplemented with the glutathione (GSH) precursor S -adenosyl-methionine (SAM-e). Term pups were given GBS intratracheally while some were pretreated with inhaled GSH prior to the experimental GBS. Neonatal lung and whole blood were evaluated for GBS while isolated AM were evaluated using fluorescent microscopy for GBS phagocytosis. Results:, Ethanol-exposed pups demonstrated increased lung infection and sepsis while AM phagocytosis of GBS was deficient compared with control. When SAM-e was added to the maternal diet containing ETOH, neonatal lung and systemic infection from GBS was attenuated and AM phagocytosis was improved. Inhaled GSH therapy prior to GBS similarly protected the ETOH-exposed pup from lung and systemic infection. Conclusions:, In utero ETOH exposure impaired the neonatal lung's defense against experimental GBS, while maintaining GSH availability protected the ETOH-exposed lung. This study suggested that fetal alcohol exposure deranges the neonatal lung's defense against bacterial infection, and support further investigations into the potential therapeutic role for exogenous GSH to augment neonatal AM function. [source] Screening Strategies for Group B Streptococcus in the Third Trimester of PregnancyJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 12 2002APRN-BC, FAANP, Lorna Schumann PhD Purpose To identify the best screening protocol to prevent neonatal group B streptococcal (GBS) sepsis through literature review. Data Sources Selected research articles, texts, and Internet sources. Conclusions Centers for Disease Control and Prevention (CDC), American Academy of Pediatrics (AAP), American College of Obstetricians and Gynecologists (ACOG), and American College of Nurse Midwives (ACNM) have issued guidelines describing methods to identify pregnant women at risk of intrapartum transmission of GBS to their babies. Studies have been conducted to discover the superiority of one prevention method over the other but no consensus has been reached. Implications for Practice Before widely used prevention methods, approximately 8,000 babies each year became infected with GBS; of those, 400 died and many survivors suffered life-long sequelae. Adoption of an appropriate protocol can prevent transmission of GBS from a colonized mother to her infant. Clinicians should implement either universal culture-based or risk factor-based screening guidelines for prenatal diagnosis and intrapartum prophylaxis of GBS disease. [source] Threonine phosphorylation prevents promoter DNA binding of the Group B Streptococcus response regulator CovRMOLECULAR MICROBIOLOGY, Issue 6 2009Wan-Jung Lin Summary All living organisms communicate with the external environment for their survival and existence. In prokaryotes, communication is achieved by two-component systems (TCS) comprising histidine kinases and response regulators. In eukaryotes, signalling is accomplished by serine/threonine and tyrosine kinases. Although TCS and serine/threonine kinases coexist in prokaryotes, direct cross-talk between these families was first described in Group B Streptococcus (GBS). A serine/threonine kinase (Stk1) and a TCS (CovR/CovS) co-regulate toxin expression in GBS. Typically, promoter binding of regulators like CovR is controlled by phosphorylation of the conserved active site aspartate (D53). In this study, we show that Stk1 phosphorylates CovR at threonine 65. The functional consequence of threonine phosphorylation of CovR in GBS was evaluated using phosphomimetic and silencing substitutions. GBS encoding the phosphomimetic T65E allele are deficient for CovR regulation unlike strains encoding the non-phosphorylated T65A allele. Further, compared with wild-type or T65A CovR, the T65E CovR is unable to bind promoter DNA and is decreased for phosphorylation at D53, similar to Stk1-phosphorylated CovR. Collectively, we provide evidence for a novel mechanism of response regulator control that enables GBS (and possibly other prokaryotes) to fine-tune gene expression for environmental adaptation. [source] Lactococcus lactis produces short-chain quinones that cross-feed Group B Streptococcus to activate respiration growthMOLECULAR MICROBIOLOGY, Issue 5 2008Lahcen Rezaďki Summary Quinones are essential components of the respiration chain that shuttle electrons between oxidoreductases. We characterized the quinones synthesized by Lactococcus lactis, a fermenting bacterium that activates aerobic respiration when a haem source is provided. Two distinct subgroups were characterized: Menaquinones (MK) MK-8 to MK-10, considered as hallmarks of L. lactis, are produced throughout growth. MK-3 and demethylMK-3 [(D)MK-3] are newly identified and are present only late in growth. Production of (D)MK-3 was conditional on the carbon sugar and on the presence of carbon catabolite regulator gene ccpA. Electron flux driven by both (D)MK fractions was shared between the quinol oxidase and extracellular acceptors O2, iron and, with remarkable efficiency, copper. Purified (D)MK-3, but not MK-8,10, complemented a menB defect in L. lactis. We previously showed that a respiratory metabolism is activated in Group B Streptococcus (GBS) by exogenous haem and MK, and that this activity is implicated in virulence. Here we show that growing lactococci donate (D)MK to GBS to activate respiration and stimulate growth of this opportunist pathogen. We propose that conditions favouring (D)MK production in dense microbial ecosystems, as present in the intestinal tract, could favour implantation of (D)MK-scavengers like GBS within the complex. [source] The colonization incidence of group B streptococcus in pregnant women and their newborns in IstanbulPEDIATRICS INTERNATIONAL, Issue 1 2005Ilikkan Barbaros Abstracts,Background:,This study was designed to determine the incidence of group B Streptococcus (GBS) colonization in pregnant women and newborns, and to evaluate the antimicrobial resistance during delivery. Methods:,A total of 300 pregnant women and their newborns were enrolled in this prospective study performed in the maternity ward of Cerrahpasa Medical Faculty and Bakirkoy SSK Hospital, Istanbul, Turkey. Samples were collected from pregnant women and their newborns in the delivery room. Results:,GBS was isolated from 24 women and the colonization rate was found to be 8%. Two newborns were colonized with GBS. None of the isolates were resistant to penicillin, whereas 20% showed resistance to erythromycin and clindamycin. Conclusion:,Screening and antimicrobial susceptibility testing of GBS during pregnancy show similiar results with other studies performed in different regions of our country. [source] Protein expression changes induced in murine peritoneal macrophages by Group B StreptococcusPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 11 2010Federica Susta Abstract Protein expression changes induced in thioglycolate-elicited peritoneal murine macrophages (M,) by infection with type III Group B Streptococcus (GBS) are described. Proteins from control M, and M, incubated 2,h with live or heat-inactivated GBS were separated by 2-DE. Proteins whose expression was significantly different in infected M,, as compared with control cells, were identified by MS/MS analysis. Changes in the expression level of proteins involved in both positive and negative modulation of phagocytic functions, stress response and cell death were induced in M, by GBS infection. In particular, expression of enzymes playing a key role in production of reactive oxygen species was lowered in GBS-infected M,. Significant alterations in the expression of some metabolic enzymes were also observed, most of the glycolytic and of the pentose-cycle enzymes being down-regulated in M, infected with live GBS. Finally, evidence was obtained that GBS infection affects the expression of enzymes or enzyme subunits involved in ATP synthesis and in adenine nucleotides interconversion processes. [source] Antenatal screening and intrapartum management of Group B Streptococcus in the UKBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 3 2004Sara Kenyon Objective To determine whether there has been any change in UK policy for the screening and intrapartum management of Group B Streptococcus in pregnancy over a two year period. Design Two national survey's of practice carried out in 1999 and 2001. Setting All obstetric units in the UK. Population Clinical directors of maternity services. Methods A questionnaire was sent to all clinical directors of maternity services in the UK requesting information about their policy and practice with respect to antenatal screening for Group B Streptococcus colonisation. Reminders were sent after one month. Main outcome measures Number of maternity units in the UK screening and offering intrapartum antibiotic prophylaxis for Group B Streptococcus colonisation in pregnancy. Results The response rates were 84% in 1999 and 82% in 2001. Of the responding units, six (3%) in 1999 and four (2%) in 2001 used vaginal swab based screening for Group B Streptococcus colonisation in the antenatal period. In 1999, intrapartum antibiotic prophylaxis was offered to women with a previous baby affected by Group B Streptococcus in 85% (176/207) of maternity units and in 2001 this had risen to 95% (193/203). Similarly, in 1999 intrapartum antibiotic prophylaxis was offered to women who were known carriers of Group B Streptococcus in 87% (179/207) of maternity units and in 2001 this had risen to 95% (193/203). Appropriate dosage of a recommended antibiotic was prescribed in 7% (9/123) units in 1999 and in 20% (35/178) units in 2001. Conclusions Although intrapartum antibiotic prophylaxis for women at high risk of giving birth to babies with Group B Streptococcus is widely practiced in the UK, a programme of antenatal screening for Group B Streptococcus colonisation has not been adopted along the lines advocated in the USA. There therefore remains an opportunity to evaluate such a screening programme in a randomised trial. [source] Children with Bacterial Meningitis Presenting to the Emergency Department during the Pneumococcal Conjugate Vaccine EraACADEMIC EMERGENCY MEDICINE, Issue 6 2008Lise E. Nigrovic MD Abstract Background:, The epidemiology of bacterial meningitis in children in the era of widespread heptavalent conjugate pneumococcal vaccination (PCV7) is unknown. Objectives:, The objective was to describe the epidemiology of bacterial meningitis in children presenting to the emergency department (ED) during the era of widespread PCV7 vaccination. Methods:, The authors retrospectively reviewed the medical records of all children aged 1 month to 19 years with bacterial meningitis who presented to the EDs of 20 U.S. pediatric centers (2001,2004). Bacterial meningitis was defined by a positive cerebrospinal fluid (CSF) culture for a bacterial pathogen or CSF pleocytosis (CSF white blood cell [WBC] count ,10 cells/mm3) in association with either a positive blood culture or a CSF latex agglutination study. Results:, A total of 231 children with bacterial meningitis were identified. The median age was 0.6 years (interquartile range [IQR] = 0.2,4.2). Eight patients (3% of all patients) died. The following bacterial pathogens were identified: Streptococcus pneumoniae (n = 77; 33.3%), Neisseria meningitidis (67; 29.0%), Group B Streptococcus (42; 18.2%), Escherichia coli (17; 7.4%), nontypeable Haemophilus influenzae (10; 4.3%), other Gram-negative bacilli (7; 3.0%), Listeria monocytogenes (5; 2.2%), Group A Streptococcus (5; 2.2%), and Moraxella catarrhalis (1; 0.4%). S. pneumoniae serotypes were determined in 37 of 77 patients; of these, 62% were due to nonvaccine serotypes (including 19A). Conclusions:, Although now a rare infectious disease in United States, bacterial meningitis still causes substantial morbidity in affected children. Despite the introduction of PCV7, S. pneumoniae remains the most common cause of bacterial meningitis in U.S. children, with approximately half of cases due to nonvaccine serotypes. [source] Late and ultra late onset Streptococcus B meningitis: clinical and bacteriological data over 6 years in FranceACTA PAEDIATRICA, Issue 1 2010J Guilbert Abstract Background:, Group B Streptococcus (GBS) is one of the leading causes of sepsis and meningitis in newborn. The objective of this study was to describe the characteristics of GBS meningitis in children aged between 7 and 89 days (late onset disease , LOD group) and to compare them with children aged more than 3 months (ultra late onset disease , ULOD group). Methods: Clinical and biological data were gathered by ACTIV/GPIP (a nationwide active surveillance network). The study population included 242 children hospitalized between 2001 and 2006 for GBS meningitis (220 in the LOD group and 22 in the ULOD group). Results:, Univariate analysis revealed that gestational age (GA) was significantly lower in the ULOD group as compared with the LOD group (respectively 35.6 weeks vs. 37.9 weeks, p = 0.002). Prevalence of early preterm birth (before the 32nd week GA) was significantly higher in the ULOD group than in the LOD group (32% vs. 7%, p = 0.002). No significant difference was found between the two groups for biological characteristics of lumbar puncture, GBS serotypes, complications and survival rate. Conclusion: These data suggest that LOD and ULOD would be the same clinical and bacteriological entity, except for prematurity, which seems significantly associated with ULOD. [source] Influence of probiotic vaginal lactobacilli on in vitro adhesion of urogenital pathogens to vaginal epithelial cellsLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2006G. Zárate Abstract Aims:, Lactobacilli, the predominant micro-organisms of the vaginal microbiota, play a major role in the maintenance of a healthy urogenital tract by preventing the colonization of pathogenic bacteria. The aim of the present study was to assess the ability of four vaginal Lactobacillus strains, previously selected for their probiotic features, to block in vitro the adherence of three human urogenital pathogens to vaginal epithelial cells (VEC). Methods and Results:, Three types of assays were performed in order to determine the inhibitory effect of lactobacilli on adhesion of urogenital pathogens to VEC: blockage by exclusion (lactobacilli and VEC followed by pathogens), competition (lactobacilli, VEC and pathogens together) and displacement (pathogens and VEC followed by the addition of lactobacilli). Bacterial adhesion to VEC was quantified by microscopy (×1000) after Gram's stain. All the strains were able to inhibit by exclusion and competition the adhesion of Staphylococcus aureus to VEC but none was able to decrease the attachment of Escherichia coli by neither of the mechanisms assayed. Only Lactobacillus acidophillus CRL 1259 and Lactobacillus paracasei CRL 1289 inhibited the attachment of Group B streptococci (GBS) to VEC by exclusion and competition respectively. Conclusions:,Lactobacillus of vaginal origin were able to inhibit the attachment of genitouropathogenic Staph. aureus and GBS to the vaginal epithelium. Significance and Impact of the Study:, The results support the probiotic potential of these Lactobacillus strains as anti-infective agents in the vagina and encourage further studies about their capacity to prevent and manage urogenital tract infections in females. [source] Regulation of purine biosynthesis by a eukaryotic-type kinase in Streptococcus agalactiaeMOLECULAR MICROBIOLOGY, Issue 5 2005Lakshmi Rajagopal Summary Group B streptococci (GBS) are the principal causal agents of human neonatal pneumonia, sepsis and meningitis. We had previously described the existence of a eukaryotic-type serine/threonine kinase (Stk1) and phosphatase (Stp1) in GBS that regulate growth and virulence of the pathogen. Our previous results also demonstrated that these enzymes reversibly phosphorylated an inorganic pyrophosphatase. To understand the role of these eukaryotic-type enzymes on growth of GBS, we assessed the stk1 -mutants for auxotrophic requirements. In this report, we describe that in the absence of the kinase (Stk1), GBS are attenuated for de novo purine biosynthesis and are consequently growth arrested. During growth in media lacking purines, the intracellular G nucleotide pools (GTP, GDP and GMP) are significantly reduced in the Stk1-deficient strains, while levels of A nucleotides (ATP, ADP and AMP) are marginally increased when compared with the isogenic wild-type strain., We, provide, evidence, that, the, reduced, pools of, G, nucleotides, result, from, altered, activity, of, the IMP utilizing enzymes, adenylosuccinate synthetase (PurA) and IMP dehydrogenase (GuaB) in these strains. We also demonstrate that Stk1 and Stp1 reversibly phosphorylate and consequently regulate PurA activity in GBS. Collectively, these data indicate the novel role of eukaryotic-type kinases in regulation of metabolic processes such as purine biosynthesis. [source] ORIGINAL ARTICLE: Isolation of Non-Activated Monocytes from Human Umbilical Cord BloodAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010Erik Normann Problem, Methods for monocyte purification are common but few work with umbilical cord monocytes that do not activate the cell for subsequent culture analysis. Methods of study, The collection procedure avoids use of needles and procedures that variably activate blood clotting and uses a purification procedure that involves diluted Ficoll, autologous serum to remove platelets and 42% and 51% Percoll step gradients for the final purification. The resulting monocytes were stimulated with bacterial lipopolysaccharide and formalin-treated bacteria Escherichia coli and group B streptococci (GBS) to secrete TNF-, and IL-1,, measured by ELISA. Results, The purification procedure results in non-active but stimulation-competent monocytes with high yields (2.3,9 × 107 cells) and purity (from 70% to 98%). Conclusion, We describe a procedure that is easy, uses common reagents and provides a uniformly high yield and purity of non-activated fetal monocytes for studies of innate defense responses. [source] Distribution of genotypes and antibiotic resistance genes among invasive Streptococcus agalactiae (group B streptococcus) isolates from Australasian patients belonging to different age groupsCLINICAL MICROBIOLOGY AND INFECTION, Issue 3 2008Z. Zhao Abstract Serotype distribution and antibiotic resistance (AR) among group B streptococci (GBS) affect GBS disease prevention strategies, but vary among patient groups. A multiplex PCR-based reverse line blot (mPCR/RLB) hybridisation assay was used to compare the distributions of GBS serotypes, serotype III subtypes and AR-associated genes among 666 invasive isolates from 663 patients, divided into five age groups: infants, early-onset (EO; 0,6 days) and late-onset (LO; 7,90 days); children (aged 3 months to 14 years); women of childbearing age (WCBA; aged 15,45 years); and other adults (males aged >15 years; females aged >45 years). Serotypes Ia and V and serosubtype III-1 accounted for 60% of infections. Serosubtype III-2, which corresponds to a virulent clone belonging to sequence type (ST)17, was relatively uncommon overall (7%), but was associated strongly with LO infant infections, in which it was significantly more common than in adult infections (25/104 (24%) vs. 9/392 (2%), p <0.0001) or in EO infections (25/104 (24%) vs. 14/155 (9%), p <0.005). Erythromycin resistance genes were found in 8% of all isolates (ermB 3%, ermA 2.5% and mefA/E 2%), in 11,15% of isolates of serotypes II and V and subtype III-1, but in none of the isolates of serosubtype III-2 (III-2, 0/49 vs. all others, 54/618 (9%), p <0.04). In summary, the virulent serosubtype III-2 was associated strongly with LO infant GBS infection, but was less likely than other serotypes or serosubtype III-1 to carry AR genes. [source] Genetic relatedness between group B streptococci originating from bovine mastitis and a human group B streptococcus type V cluster displaying an identical pulsed-field gel electrophoresis patternCLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2006I. C. M. Oliveira Abstract Twenty isolates of group B streptococcus (GBS) were recovered from the milk of cows with bovine mastitis on three farms located in the south and south-east of Brazil between 1987 and 1988. These isolates were characterised by molecular methods and compared with a collection of 103 human GBS isolates from colonised and infected patients in the same region between 1980 and 2003. Some of the bovine isolates shared identical or similar pulsed-field gel electrophoresis (PFGE) patterns with a PFGE clone of human GBS type V. In addition, these bovine and human isolates also possessed the same ribotype. Multilocus sequence typing (MLST) of representative isolates confirmed the genetic relationship between the human and bovine GBS isolates with identical PFGE patterns, which clustered in the same ST-26 clonal complex. These data support the hypothesis that some bovine GBS strains are related closely to human isolates and may infect humans, or vice versa. Further comparative genomic analyses of GBS isolates from bovine and human origins are required to investigate this hypothesis further. [source] Evasion of macrophage scavenger receptor A-mediated recognition by pathogenic streptococciEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2008Thomas Areschoug Abstract PRR recognize conserved structures on pathogenic microbes and are important for the defense against invading microorganisms. However, accumulating evidence indicates that many pathogens have evolved mechanisms to avoid recognition by PRR. One type of PRR is the macrophage scavenger receptor A (SR-A), which has been shown to play an important role in recognition and non-opsonic phagocytosis of pathogenic bacteria. The bacterial ligands for SR-A have been suggested to be LPS or lipoteichoic acid. Here, we use murine bone marrow-derived macrophages to analyze the role of SR-A in non-opsonic phagocytosis of two major Gram-positive pathogens, Streptococcus agalactiae (group B streptococcus; GBS) and Streptococcus pyogenes. We show that the polysaccharide capsule of GBS and the surface M protein of S. pyogenes, two important virulence factors, prevent SR-A-mediated non-opsonic phagocytosis of streptococci. The sialic acid moiety of the GBS capsule was crucial for its ability to prevent recognition by SR-A. Moreover, we show that a ligand on GBS recognized by SR-A in the absence of capsule is the surface lipoprotein Blr. These findings represent the first example of a microbial strategy to prevent recognition by SR-A and suggest that bacterial surface proteins may be of importance as ligands for SR-A. [source] Incubation time required for neonatal blood cultures to become positiveJOURNAL OF PAEDIATRICS AND CHILD HEALTH, Issue 12 2006Luke Jardine Aim: We aimed to determine the laboratory detection time of bacteraemia in neonatal blood cultures, and whether this differed by: organism; samples deemed to represent true bacteraemia versus contaminants; and blood cultures collected from an infant <48 h of age (early) or ,48 h of age (late). Methods: A retrospective audit of all positive blood cultures collected from neonates in the Grantley Stable Neonatal Unit, Royal Women's Hospital, Brisbane, between 1 January 2000 and 31 December 2004 was undertaken. The bacteraemia detection method used was the BacTAlert system with Peds bottles. Results: Two hundred and three positive blood cultures were included in the analysis. One hundred and sixteen (57%) were deemed septicaemia, 87 (43%) were deemed contaminants. The median (interquartile range) time to positivity for positive blood cultures deemed septicaemia and contaminants were 15.9 (11.6, 22.2) and 30.2 (20.4, 43.9) h, respectively. Fifty-six (28%) positive blood cultures were collected when infants were <48 h of age and 147 (72%) were collected in infants ,48 h of age. Post hoc analysis revealed that the time to positivity for early septicaemia was 13.7 (11, 16.7) h; early contaminant was 25.2 (19.2, 33.8) h; late septicaemia was 17.2 (12.2, 23.4) h; and late contaminant was 37.9 (21.7, 51.2) h. The time to positivity for: Group B streptococcus was 9.3 (8.2, 11.0) h; Escherichia coli was 11.3 (10.0, 13.5) h; and coagulase-negative staphylococci was 28.9 (20.5, 41.2) h. Conclusion: The incubation time for positive blood cultures significantly differs by organism type and whether they are considered early or late septicaemia versus contaminants. We recommend that: infants who are <48 h of age at the time of blood culture collection, who remain clinically well and have negative cultures 36 h after the initial collection can safely have their antibiotic treatment ceased; infants who are ,48 h of age at the time of collection should continue antibiotic treatment for at least 48 h before cessation is considered. [source] N -Acetylcysteine Improves Group B Streptococcus Clearance in a Rat Model of Chronic Ethanol IngestionALCOHOLISM, Issue 7 2009Sonja M. Tang Background:, Sepsis is the most common risk factor associated with acute respiratory distress syndrome (ARDS) and results in a 40,60% mortality rate due to respiratory failure. Furthermore, recent epidemiological studies have demonstrated that a history of alcohol abuse increases the risk of ARDS by 3.6-fold. More recently, group B streptococcus (GBS) infections in nonpregnant adults have been increasing, particularly in alcoholics where there is an increased risk of lobular invasion and mortality. We have shown in an established rat model that chronic ethanol ingestion impaired macrophage internalization of inactivated infectious particles in vitro and enhanced bidirectional protein flux across the alveolar epithelial-endothelial barriers, both of which were attenuated when glutathione precursors were added to the diet. We hypothesized that chronic ethanol ingestion would increase the risk of infection even though GBS is less pathogenic but that dietary N -acetylcysteine (NAC), a glutathione precursor, would improve in vivo clearance of infectious particles and reduce systemic infection. Methods:, After 6 weeks of ethanol feeding, rats were given GBS intratracheally and sacrificed 24 hours later. GBS colony-forming units were counted in the lung, liver, spleen, and bronchoalveolar lavage fluid. Acute lung injury in response to GBS was also assessed. Results:, Chronic ethanol exposure decreased GBS clearance from the lung indicating an active lung infection. In addition, increased colonies formed within the liver and spleen indicated that ethanol increased the risk of systemic infection. Ethanol also exacerbated the acute lung injury induced by GBS. NAC supplementation normalized GBS clearance by the lung, prevented the appearance of GBS systemically, and attenuated acute lung injury. Conclusions:, These data suggested that chronic alcohol ingestion increased the susceptibility of the lung to bacterial infections from GBS as well as systemic infections. Furthermore, dietary NAC improved in vivo clearance of GBS particles, attenuated acute lung injury, and disseminated infection. [source] The colonization incidence of group B streptococcus in pregnant women and their newborns in IstanbulPEDIATRICS INTERNATIONAL, Issue 1 2005Ilikkan Barbaros Abstracts,Background:,This study was designed to determine the incidence of group B Streptococcus (GBS) colonization in pregnant women and newborns, and to evaluate the antimicrobial resistance during delivery. Methods:,A total of 300 pregnant women and their newborns were enrolled in this prospective study performed in the maternity ward of Cerrahpasa Medical Faculty and Bakirkoy SSK Hospital, Istanbul, Turkey. Samples were collected from pregnant women and their newborns in the delivery room. Results:,GBS was isolated from 24 women and the colonization rate was found to be 8%. Two newborns were colonized with GBS. None of the isolates were resistant to penicillin, whereas 20% showed resistance to erythromycin and clindamycin. Conclusion:,Screening and antimicrobial susceptibility testing of GBS during pregnancy show similiar results with other studies performed in different regions of our country. [source] Structure of laminin-binding adhesin (Lmb) from Streptococcus agalactiaeACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2009Preethi Ragunathan Adhesion/invasion of pathogenic bacteria is a critical step in infection and is mediated by surface-exposed proteins termed adhesins. The crystal structure of recombinant Lmb, a laminin-binding adhesin from Streptococcus agalactiae, has been determined at 2.5,Ĺ resolution. Based on sequence and structural homology, Lmb was placed into the cluster 9 family of the ABC (ATP-binding cassette) transport system. The structural organization of Lmb closely resembles that of ABC-type solute-binding proteins (SBPs), in which two structurally related globular domains interact with each other to form a metal-binding cavity at the interface. The bound zinc in Lmb is tetrahedrally coordinated by three histidines and a glutamate from both domains. A comparison of Lmb with other metal transporters revealed an interesting feature of the dimerization of molecules in the crystallographic asymmetric unit in all zinc-binding transporters. A closer comparison of Lmb with the zinc-binding ZnuA from Escherichia coli and Synechocystis 6803 suggested that Lmb might undergo a unique structural rearrangement upon metal binding and release. The crystal structure of Lmb provides an impetus for further investigations into the molecular basis of laminin binding by human pathogens. Being ubiquitous in all serotypes of group B streptococcus (GBS), the structure of Lmb may direct the development of an efficient vaccine. [source] Expression, purification, crystallization and preliminary crystallographic analysis of laminin-binding protein (Lmb) from Streptococcus agalactiaeACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2009Preethi Ragunathan Laminin-binding protein (Lmb), a surface-exposed lipoprotein from Streptococcus agalactiae (group B streptococcus), mediates attachment to human laminin and plays a crucial role in the adhesion/invasion of eukaryotic host cells. However, the structural basis of laminin binding still remains unclear. In the context of detailed structural analysis, the lmb gene has been cloned, expressed in Escherichia coli, purified and crystallized. The crystals diffracted to a resolution of 2.5,Ĺ and belonged to the monoclinic space group P21, with unit-cell parameters a = 56.63, b = 70.60, c = 75.37,Ĺ, , = 96.77°. [source] Scavenger receptors: role in innate immunity and microbial pathogenesisCELLULAR MICROBIOLOGY, Issue 8 2009Thomas Areschoug Summary Accumulating evidence shows that many scavenger receptors (SR), including SR-A, MARCO and CD36, represent an important part of the innate immune defence by acting as pattern-recognition receptors, in particular against bacterial pathogens. Several SR are expressed on macrophages and dendritic cells, where they act as phagocytic receptors mediating non-opsonic phagocytosis of pathogenic microbes. Another important function of some SR is to act as co-receptors to Toll-like receptors (TLR), modulating the inflammatory response to TLR agonists. On bacteria, the SR ligands have commonly been reported to be lipopolysaccharide and lipoteichoic acid, but recent advances in the field indicate that bacterial surface proteins play a more important role as target molecules for SR than previously thought. Interestingly, recent data show that major pathogens, including Streptococcus pyogenes and the group B streptococcus, have evolved mechanisms to evade SR-mediated recognition. Moreover, intracellular pathogens, such as hepatitis C virus and Plasmodium falciparum, utilize the SR to gain entry into host cells, focusing interest on the importance of SR also in the molecular pathogenesis of infectious diseases. This review highlights the complex interactions between SR and pathogenic microbes, and discusses the role of these interactions in host defence and microbial pathogenesis. [source] Distribution of genotypes and antibiotic resistance genes among invasive Streptococcus agalactiae (group B streptococcus) isolates from Australasian patients belonging to different age groupsCLINICAL MICROBIOLOGY AND INFECTION, Issue 3 2008Z. Zhao Abstract Serotype distribution and antibiotic resistance (AR) among group B streptococci (GBS) affect GBS disease prevention strategies, but vary among patient groups. A multiplex PCR-based reverse line blot (mPCR/RLB) hybridisation assay was used to compare the distributions of GBS serotypes, serotype III subtypes and AR-associated genes among 666 invasive isolates from 663 patients, divided into five age groups: infants, early-onset (EO; 0,6 days) and late-onset (LO; 7,90 days); children (aged 3 months to 14 years); women of childbearing age (WCBA; aged 15,45 years); and other adults (males aged >15 years; females aged >45 years). Serotypes Ia and V and serosubtype III-1 accounted for 60% of infections. Serosubtype III-2, which corresponds to a virulent clone belonging to sequence type (ST)17, was relatively uncommon overall (7%), but was associated strongly with LO infant infections, in which it was significantly more common than in adult infections (25/104 (24%) vs. 9/392 (2%), p <0.0001) or in EO infections (25/104 (24%) vs. 14/155 (9%), p <0.005). Erythromycin resistance genes were found in 8% of all isolates (ermB 3%, ermA 2.5% and mefA/E 2%), in 11,15% of isolates of serotypes II and V and subtype III-1, but in none of the isolates of serosubtype III-2 (III-2, 0/49 vs. all others, 54/618 (9%), p <0.04). In summary, the virulent serosubtype III-2 was associated strongly with LO infant GBS infection, but was less likely than other serotypes or serosubtype III-1 to carry AR genes. [source] Genetic relatedness between group B streptococci originating from bovine mastitis and a human group B streptococcus type V cluster displaying an identical pulsed-field gel electrophoresis patternCLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2006I. C. M. Oliveira Abstract Twenty isolates of group B streptococcus (GBS) were recovered from the milk of cows with bovine mastitis on three farms located in the south and south-east of Brazil between 1987 and 1988. These isolates were characterised by molecular methods and compared with a collection of 103 human GBS isolates from colonised and infected patients in the same region between 1980 and 2003. Some of the bovine isolates shared identical or similar pulsed-field gel electrophoresis (PFGE) patterns with a PFGE clone of human GBS type V. In addition, these bovine and human isolates also possessed the same ribotype. Multilocus sequence typing (MLST) of representative isolates confirmed the genetic relationship between the human and bovine GBS isolates with identical PFGE patterns, which clustered in the same ST-26 clonal complex. These data support the hypothesis that some bovine GBS strains are related closely to human isolates and may infect humans, or vice versa. Further comparative genomic analyses of GBS isolates from bovine and human origins are required to investigate this hypothesis further. [source] | ||||||||||||||||||||||||||||