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Pellegrini A, Lentini G, Famà A, Bonacorsi A, Scoffone VC, Buroni S, Trespidi G, Postiglione U, Sassera D, Manai F, Pietrocola G, Firon A, Biondo C, Teti G, Beninati C, Barbieri G. CodY Is a Global Transcriptional Regulator Required for Virulence in Group B Streptococcus. Front Microbiol 2022; 13:881549. [PMID: 35572655 PMCID: PMC9096947 DOI: 10.3389/fmicb.2022.881549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 03/21/2022] [Indexed: 12/03/2022] Open
Abstract
Group B Streptococcus (GBS) is a Gram-positive bacterium able to switch from a harmless commensal of healthy adults to a pathogen responsible for invasive infections in neonates. The signals and regulatory mechanisms governing this transition are still largely unknown. CodY is a highly conserved global transcriptional regulator that links nutrient availability to the regulation of major metabolic and virulence pathways in low-G+C Gram-positive bacteria. In this work, we investigated the role of CodY in BM110, a GBS strain representative of a hypervirulent lineage associated with the majority of neonatal meningitis. Deletion of codY resulted in a reduced ability of the mutant strain to cause infections in neonatal and adult animal models. The observed decreased in vivo lethality was associated with an impaired ability of the mutant to persist in the blood, spread to distant organs, and cross the blood-brain barrier. Notably, the codY null mutant showed reduced adhesion to monolayers of human epithelial cells in vitro and an increased ability to form biofilms, a phenotype associated with strains able to asymptomatically colonize the host. RNA-seq analysis showed that CodY controls about 13% of the genome of GBS, acting mainly as a repressor of genes involved in amino acid transport and metabolism and encoding surface anchored proteins, including the virulence factor Srr2. CodY activity was shown to be dependent on the availability of branched-chain amino acids, which are the universal cofactors of this regulator. These results highlight a key role for CodY in the control of GBS virulence.
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Affiliation(s)
- Angelica Pellegrini
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | - Germana Lentini
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Agata Famà
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Andrea Bonacorsi
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | - Viola Camilla Scoffone
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | - Silvia Buroni
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | - Gabriele Trespidi
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | - Umberto Postiglione
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | - Davide Sassera
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | - Federico Manai
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
| | | | - Arnaud Firon
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Unité Biologie des Bactéries Pathogènes à Gram-positif, Paris, France
| | - Carmelo Biondo
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | | | - Concetta Beninati
- Department of Human Pathology and Medicine, University of Messina, Messina, Italy
| | - Giulia Barbieri
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, Pavia, Italy
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Lukić I, Getselter D, Koren O, Elliott E. Role of Tryptophan in Microbiota-Induced Depressive-Like Behavior: Evidence From Tryptophan Depletion Study. Front Behav Neurosci 2019; 13:123. [PMID: 31231198 PMCID: PMC6558209 DOI: 10.3389/fnbeh.2019.00123] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/20/2019] [Indexed: 12/26/2022] Open
Abstract
During the past decade, there has been a substantial rise in the knowledge about the effects of gut microbiota on host physiology and behavior, including depressive behavior. Initial studies determined that gut microbiota can regulate host tryptophan levels, which is a main serotonin precursor. A dysfunctional serotonergic system is considered to be one of the main factors contributing to the development of depression. Therefore, we hypothesized that regulation of brain tryptophan and serotonin can explain, at least partly, the effects of microbiota on depressive behavior. To test this hypothesis, we examined depressive-like behavior and brain levels of serotonin and tryptophan, of germ free (GF) and specific-pathogen free (SPF) mice under basal conditions, or after acute tryptophan depletion (ATD) procedure, which is a method to decrease tryptophan and serotonin levels in the brain. In basal conditions, GF mice exhibited less depressive-like behavior in sucrose preference, tail-suspension and forced swim tests, compared to SPF mice. In addition, in mice that were not subjected to ATD, GF mice displayed higher levels of tryptophan, serotonin and 5-hydroxyindoleacetic acid (the main degradation product of serotonin) in medial prefrontal cortex (mPFC) and hippocampus (HIPPO), compared to SPF mice. Interestingly, ATD increased depressive-like behavior of GF, but not of SPF mice. These behavioral changes were accompanied by a stronger reduction of tryptophan, serotonin and 5-hydroxyindoleacetic acid in mPFC and HIPPO in GF mice after ATD, when compared to SPF mice. Therefore, the serotonergic system of GF mice is more vulnerable to the acute challenge of tryptophan reduction, and GF mice after tryptophan reduction behave more similarly to SPF mice. These data provide functional evidence that microbiota affects depression-like behavior through influencing brain tryptophan accessibility and the serotonergic system.
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Affiliation(s)
- Iva Lukić
- Molecular and Behavioral Neuroscience, Bar-Ilan University, Safed, Israel
| | - Dmitriy Getselter
- Molecular and Behavioral Neuroscience, Bar-Ilan University, Safed, Israel
| | - Omry Koren
- Microbiome Research Laboratories, The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Evan Elliott
- Molecular and Behavioral Neuroscience, Bar-Ilan University, Safed, Israel
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Tavares GC, Pereira FL, Barony GM, Rezende CP, da Silva WM, de Souza GHMF, Verano-Braga T, de Carvalho Azevedo VA, Leal CAG, Figueiredo HCP. Delineation of the pan-proteome of fish-pathogenic Streptococcus agalactiae strains using a label-free shotgun approach. BMC Genomics 2019; 20:11. [PMID: 30616502 PMCID: PMC6323687 DOI: 10.1186/s12864-018-5423-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 12/27/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Streptococcus agalactiae (GBS) is a major pathogen of Nile tilapia, a global commodity of the aquaculture sector. The aims of this study were to evaluate protein expression in the main genotypes of GBS isolated from diseased fishes in Brazil using a label-free shotgun nano-liquid chromatography-ultra definition mass spectrometry (nanoLC-UDMSE) approach and to compare the differential abundance of proteins identified in strains isolated from GBS-infected fishes and humans. RESULTS A total of 1070 protein clusters were identified by nanoLC-UDMSE in 5 fish-adapted GBS strains belonging to sequence types ST-260 and ST-927 and the non-typeable (NT) lineage and 1 human GBS strain (ST-23). A total of 1065 protein clusters corresponded to the pan-proteome of fish-adapted GBS strains; 989 of these were identified in all fish-adapted GBS strains (core proteome), and 62 were shared by at least two strains (accessory proteome). Proteins involved in the stress response and in the regulation of gene expression, metabolism and virulence were detected, reflecting the adaptive ability of fish-adapted GBS strains in response to stressor factors that affect bacterial survival in the aquatic environment and bacterial survival and multiplication inside the host cell. Measurement of protein abundance among different hosts showed that 5 and 26 proteins were exclusively found in the human- and fish-adapted GBS strains, respectively; the proteins exclusively identified in fish isolates were mainly related to virulence factors. Furthermore, 215 and 269 proteins were up- and down-regulated, respectively, in the fish-adapted GBS strains in comparison to the human isolate. CONCLUSIONS Our study showed that the core proteome of fish-adapted GBS strains is conserved and demonstrated high similarity of the proteins expressed by fish-adapted strains to the proteome of the human GBS strain. This high degree of proteome conservation of different STs suggests that, a monovalent vaccine may be effective against these variants.
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Affiliation(s)
- Guilherme Campos Tavares
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Felipe Luiz Pereira
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gustavo Morais Barony
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cristiana Perdigão Rezende
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Wanderson Marques da Silva
- Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Thiago Verano-Braga
- Department of Physiology and Biophysics, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Vasco Ariston de Carvalho Azevedo
- Laboratory of Cellular and Molecular Genetics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Carlos Augusto Gomes Leal
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Henrique César Pereira Figueiredo
- AQUACEN - National Reference Laboratory of Aquatic Animal Diseases, Ministry of Agriculture, Livestock and Food Supply, Veterinary School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil. .,School of Veterinary, Department of Preventive Veterinary Medicine, Federal University of Minas Gerais, Av. Antônio Carlos 6627, Pampulha, Belo Horizonte, Minas Gerais, 30161-970, Brazil.
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Rogers GB, Keating DJ, Young RL, Wong ML, Licinio J, Wesselingh S. From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Mol Psychiatry 2016; 21:738-48. [PMID: 27090305 PMCID: PMC4879184 DOI: 10.1038/mp.2016.50] [Citation(s) in RCA: 574] [Impact Index Per Article: 71.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 02/22/2016] [Accepted: 02/25/2016] [Indexed: 02/06/2023]
Abstract
The human body hosts an enormous abundance and diversity of microbes, which perform a range of essential and beneficial functions. Our appreciation of the importance of these microbial communities to many aspects of human physiology has grown dramatically in recent years. We know, for example, that animals raised in a germ-free environment exhibit substantially altered immune and metabolic function, while the disruption of commensal microbiota in humans is associated with the development of a growing number of diseases. Evidence is now emerging that, through interactions with the gut-brain axis, the bidirectional communication system between the central nervous system and the gastrointestinal tract, the gut microbiome can also influence neural development, cognition and behaviour, with recent evidence that changes in behaviour alter gut microbiota composition, while modifications of the microbiome can induce depressive-like behaviours. Although an association between enteropathy and certain psychiatric conditions has long been recognized, it now appears that gut microbes represent direct mediators of psychopathology. Here, we examine roles of gut microbiome in shaping brain development and neurological function, and the mechanisms by which it can contribute to mental illness. Further, we discuss how the insight provided by this new and exciting field of research can inform care and provide a basis for the design of novel, microbiota-targeted, therapies.
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Affiliation(s)
- G B Rogers
- South Australian Health and Medical Research Institute, Infection and Immunity Theme, School of Medicine, Flinders University, Adelaide, SA, Australia
| | - D J Keating
- South Australian Health and Medical Research Institute, Centre for Neuroscience and Department of Human Physiology, Flinders University, Adelaide, SA, Australia
| | - R L Young
- South Australian Health and Medical Research Institute, Department of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - M-L Wong
- South Australian Health and Medical Research Institute, Mind and Brain Theme, and Flinders University, Adelaide, SA, Australia
| | - J Licinio
- South Australian Health and Medical Research Institute, Mind and Brain Theme, and Flinders University, Adelaide, SA, Australia
| | - S Wesselingh
- South Australian Health and Medical Research Institute, Infection and Immunity Theme, School of Medicine, Flinders University, Adelaide, SA, Australia
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Abstract
OBJECT
Brain abscesses could lead to cerebral symptoms through tissue destruction, edema, changes in brain architecture, and increased intracranial pressure. However, the possibility that the pus itself could contribute to symptoms has received little attention. Brain abscesses are areas of tissue destruction, proteolysis, and formation of free amino acids, which are energy substrates for bacteria and possible sources of ammonia. Ammonia is neurotoxic, may cause brain edema, and could contribute to the symptoms of brain abscesses.
METHODS
The authors analyzed the extracellular phase of pus from 14 patients with brain abscesses with respect to ammonia and amino acids. For comparison, CSF from 10 patients undergoing external ventricular drainage was included. The ammonia-forming ability of Streptococcus intermedius and Staphylococcus aureus, two common microbial isolates in brain abscesses, was studied in vitro.
RESULTS
In brain abscesses ammonia was 15.5 mmol/L (median value; range 1.7–69.2 mmol/L). In CSF ammonia was 29 μmol/L (range 17–55 μmol/L; difference from value in pus: p < 0.001). The total concentration of amino acids in brain abscesses was 1.12–16 times higher than the ammonia concentration (p = 0.011). The median glucose value in pus was 0 mmol/L (range 0–2.1 mmol/L), lactate was 21 mmol/L (range 3.3–26.5 mmol/L), and pH was 6.8 (range 6.2–7.3). In vitro, S. intermedius and S. aureus formed ammonia at 6–7 mmol/L in 24 hours when incubated with 20 proteinogenic amino acids plus g-aminobutyric acid (GABA), taurine, and glutathione at 1 mmol/L.
CONCLUSIONS
Intracerebral abscesses contain toxic levels of ammonia. At the concentrations found in pus, ammonia could contribute to the brain edema and the symptoms of brain abscesses.
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Affiliation(s)
| | | | - Bjørnar Hassel
- 2Complex Neurology and Neurohabilitation, Oslo University Hospital, Oslo; and
- 3Norwegian Defence Research Establishment (FFI), Kjeller, Norway
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Serotonin, tryptophan metabolism and the brain-gut-microbiome axis. Behav Brain Res 2014; 277:32-48. [PMID: 25078296 DOI: 10.1016/j.bbr.2014.07.027] [Citation(s) in RCA: 1106] [Impact Index Per Article: 110.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/08/2014] [Accepted: 07/16/2014] [Indexed: 12/14/2022]
Abstract
The brain-gut axis is a bidirectional communication system between the central nervous system and the gastrointestinal tract. Serotonin functions as a key neurotransmitter at both terminals of this network. Accumulating evidence points to a critical role for the gut microbiome in regulating normal functioning of this axis. In particular, it is becoming clear that the microbial influence on tryptophan metabolism and the serotonergic system may be an important node in such regulation. There is also substantial overlap between behaviours influenced by the gut microbiota and those which rely on intact serotonergic neurotransmission. The developing serotonergic system may be vulnerable to differential microbial colonisation patterns prior to the emergence of a stable adult-like gut microbiota. At the other extreme of life, the decreased diversity and stability of the gut microbiota may dictate serotonin-related health problems in the elderly. The mechanisms underpinning this crosstalk require further elaboration but may be related to the ability of the gut microbiota to control host tryptophan metabolism along the kynurenine pathway, thereby simultaneously reducing the fraction available for serotonin synthesis and increasing the production of neuroactive metabolites. The enzymes of this pathway are immune and stress-responsive, both systems which buttress the brain-gut axis. In addition, there are neural processes in the gastrointestinal tract which can be influenced by local alterations in serotonin concentrations with subsequent relay of signals along the scaffolding of the brain-gut axis to influence CNS neurotransmission. Therapeutic targeting of the gut microbiota might be a viable treatment strategy for serotonin-related brain-gut axis disorders.
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Clarke G, Stilling RM, Kennedy PJ, Stanton C, Cryan JF, Dinan TG. Minireview: Gut microbiota: the neglected endocrine organ. Mol Endocrinol 2014; 28:1221-38. [PMID: 24892638 DOI: 10.1210/me.2014-1108] [Citation(s) in RCA: 664] [Impact Index Per Article: 66.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The concept that the gut microbiota serves as a virtual endocrine organ arises from a number of important observations. Evidence for a direct role arises from its metabolic capacity to produce and regulate multiple compounds that reach the circulation and act to influence the function of distal organs and systems. For example, metabolism of carbohydrates results in the production of short-chain fatty acids, such as butyrate and propionate, which provide an important source of nutrients as well as regulatory control of the host digestive system. This influence over host metabolism is also seen in the ability of the prebiotic inulin to influence production of relevant hormones such as glucagon-like peptide-1, peptide YY, ghrelin, and leptin. Moreover, the probiotic Lactobacillus rhamnosus PL60, which produces conjugated linoleic acid, has been shown to reduce body-weight gain and white adipose tissue without effects on food intake. Manipulating the microbial composition of the gastrointestinal tract modulates plasma concentrations of tryptophan, an essential amino acid and precursor to serotonin, a key neurotransmitter within both the enteric and central nervous systems. Indirectly and through as yet unknown mechanisms, the gut microbiota exerts control over the hypothalamic-pituitary-adrenal axis. This is clear from studies on animals raised in a germ-free environment, who show exaggerated responses to psychological stress, which normalizes after monocolonization by certain bacterial species including Bifidobacterium infantis. It is tempting to speculate that therapeutic targeting of the gut microbiota may be useful in treating stress-related disorders and metabolic diseases.
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Affiliation(s)
- Gerard Clarke
- Alimentary Pharmabiotic Centre (G.C., R.M.S., P.J.K., C.S., J.F.C., T.G.D.) and Departments of Psychiatry (G.C., C.S., T.G.D.) and Anatomy and Neuroscience (J.F.C.), University College Cork, Cork, Ireland; and Teagasc (C.S.), Moorepark, Fermoy, Cork, Ireland
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Lactic acid is a potential virulence factor for group B Streptococcus. Microb Pathog 2009; 46:43-52. [DOI: 10.1016/j.micpath.2008.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 10/07/2008] [Accepted: 10/17/2008] [Indexed: 11/22/2022]
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Palacios GC, Gonzalez MN, Beltran M, Arredondo JL, Torres J, Solorzano F. High-virulence clone of group B streptococci unable to grow at high temperatures is present in serotypes other than type III. Curr Microbiol 2006; 54:42-7. [PMID: 17171465 DOI: 10.1007/s00284-006-0291-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 07/10/2006] [Indexed: 10/23/2022]
Abstract
Highly virulent clonotypes of serotype III seem to cause much of the perinatal morbidity and mortality attributed to Streptococcus agalactiae (group B streptococci, GBS), One of these clonal types, designated the "high-virulence clone" (HVC), was identified by its inability to grow at 40 degrees C in a chemically defined medium. In the present study, this inability to grow at high temperatures was used as a marker to identify HVC in a sample of 286 Mexican GBS isolates. Forty-three isolates (15%) were identified as belonging to this clone: 15 were invasive isolates, 33 were serotype III (77%), and 10 were of serotypes other than type III (23%). These results demonstrate that HVC is more prevalent in Mexico than previously reported and that this clone is not restricted to serotype III isolates.
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Affiliation(s)
- Gerardo C Palacios
- Departamento de Infectologia and Unidad de Investigacion en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
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10
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Gao HJ, Du GC, Chen J. Analysis of metabolic fluxes for hyaluronic acid (HA) production by Streptococcus zooepidemicus. World J Microbiol Biotechnol 2006. [DOI: 10.1007/s11274-005-9047-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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11
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Rosa-Fraile M, Sampedro A, Rodríguez-Granger J, García-Peña ML, Ruiz-Bravo A, Haïdour A. Pigment production by Streptococcus agalactiae in quasi-defined media. Appl Environ Microbiol 2001; 67:473-4. [PMID: 11133484 PMCID: PMC92604 DOI: 10.1128/aem.67.1.473-474.2001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A quasi-defined medium that supports the growth of Streptococcus agalactiae as pigmented colonies has been developed. The medium contains starch, a peptic digest of albumin, amino acids, nucleosides, vitamins, and salts. The presence of free cysteine, which could be replaced with other sulphur-containing compounds and to a lesser degree by reducing agents, was required for pigment formation.
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Affiliation(s)
- M Rosa-Fraile
- Microbiology Service, Virgen de las Nieves Hospital, 18014 Granada
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12
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Palacios GC, Eskew EK, Solorzano F, Mattingly SJ. Decreased capacity for type-specific-antigen synthesis accounts for high prevalence of nontypeable strains of group B streptococci in Mexico. J Clin Microbiol 1997; 35:2923-6. [PMID: 9350760 PMCID: PMC230088 DOI: 10.1128/jcm.35.11.2923-2926.1997] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The low incidence of group B streptococcal (GBS) invasive neonatal disease in Mexico has been attributed to the low prevalence of serotype III strains, a major serotype in developed countries. In addition, nontypeable strains account for 12% of the isolates in Mexico and < 1% of the isolates in the United States. In this study, 57 GBS isolates (28 nontypeable by the Lancefield procedure) from carrier and infected neonates and women from Mexico were also examined for the presence of type-specific antigen by an enzymatic procedure using N-acetylmuramidase digestion of the cell wall to release soluble type-specific antigen. Of the 28 nontypeable strains from Mexico, 23 were typeable by the enzyme extraction procedure, with serotype III being the predominant serotype in invasive disease. These results suggest that nontypeable isolates of GBS should be further examined by the enzymatic extraction procedure to determine the presence of type-specific antigen. Furthermore, these limited results suggest that serotype III is likely a major serotype in invasive disease also in Mexico.
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Affiliation(s)
- G C Palacios
- Departamento de Infectologia, Hospital de Pediatria, Instituto Mexicano del Seguro Social, Mexico City, Mexico
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13
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Sanford BA, de Feijter AW, Wade MH, Thomas VL. A dual fluorescence technique for visualization of Staphylococcus epidermidis biofilm using scanning confocal laser microscopy. JOURNAL OF INDUSTRIAL MICROBIOLOGY 1996; 16:48-56. [PMID: 8820019 DOI: 10.1007/bf01569921] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A new dual fluorescence technique is described which, when combined with scanning confocal laser microscopy (SCLM), can be used to visualize the components of biofilm produced by Staphylococcus epidermidis. Chemostat cultures of RP62A (a well-characterized slime-producing strain of S. epidermidis) were used to produce mature biofilm on polyvinylchloride (PVC) disks immobilized in a modified Robbins device using a 'seed' and 'feed' model system. Serial horizontal and vertical optical thin sections, as well as three-dimensional computer reconstructions, were obtained on in situ biofilm using the dual fluorescence procedure. Bacteria were visualized by green autofluorescence excited at 488 nm with an Argon laser. Cell-associated and exocellular matrix material (slime) was visualized by red fluorescence excited at 568 nm with a Krypton laser after interaction of the biofilm with Texas Red-labeled wheat germ agglutinin which is a slime-specific lectin marker. Structural analysis revealed that the cocci grew in slime-embedded cell clusters forming distinct conical-shaped microcolonies. Interspersed open channels served to connect the bulk liquid with the deepest layers of the mature, hydrated biofilm which increased overall surface area and likely facilitated the exchange of nutrients and waste products throughout the biofilm. The combined dual fluorescence technique and SCLM is potentially useful as a specific noninvasive tool for studying the effect of antimicrobial agents on the process of biofilm formation and for the characterization of the architecture of S. epidermidis biofilm formed in in vivo and in vitro on medical grade virgin or modified inert polymer surfaces.
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Affiliation(s)
- B A Sanford
- Department of Microbiology, University of Texas Health Science Center at San Antonio, Texas 78284, USA
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14
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Sanford BA, Thomas VL, Mattingly SJ, Ramsay MA, Miller MM. Lectin-biotin assay for slime present in in situ biofilm produced by Staphylococcus epidermidis using transmission electron microscopy (TEM). JOURNAL OF INDUSTRIAL MICROBIOLOGY 1995; 15:156-61. [PMID: 8519472 DOI: 10.1007/bf01569820] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A lectin-biotin assay was developed for use in the specific detection of slime produced by Staphylococcus epidermidis RP62A and M187sp11 grown in a chemically defined medium. Mature biofilm was formed on polyvinylchloride (PVC) disks using a combined chemostat-modified Robbins device (MRD) model system. Specimens fixed in situ were: 1) stained with ruthenium red; 2) reacted overnight with biotin-labeled lectins (WGA, succinyl-WGA, Con A, or APA) followed by treatment with gold-labeled extravidin; or 3) reacted with antibodies against S. epidermidis RP62A capsular polysaccharide/adhesin (PS/A) using an immunogold procedure. WGA and succinyl-WGA (S-WGA), which specifically bind N-acetylglucosamine, were shown by TEM to react only with slime, both cell-associated and exocellular. In contrast, Con A, APA and anti-PS/A reacted with the bacterial cell surface but did not react with slime. These results indicate the usefulness of WGA lectin as a specific marker for detection of the presence and distribution of slime matrix material in S. epidermidis biofilm.
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Affiliation(s)
- B A Sanford
- Department of Microbiology, University of Texas Health Science Center at San Antonio 78284-7758, USA
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15
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Mattingly SJ, Eskew EK. Temperature sensitivity of fructose-1,6-biphosphate aldolase accounts for the inability of the high-virulence clone ofStreptococcus agalactiae to grow at 40°C. Curr Microbiol 1993. [DOI: 10.1007/bf01577369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
A method for the analysis of lipoteichoic acid (LTA) by polyacrylamide gel electrophoresis (PAGE) is described. Purified LTA from Streptococcus agalactiae tended to smear in the upper two-thirds of a 30 to 40% linear polyacrylamide gel, while the chemically deacylated form (cdLTA) migrated as a ladder of discrete bands, reminiscent of lipopolysaccharides. The deacylated polymer appeared to separate in this system on the basis of size, as evident from results obtained from PAGE analysis of cdLTA subjected to limited acid hydrolysis and LTA that had been fractionated by gel filtration. A survey of cdLTA from other streptococci revealed similarities in molecular weight ranges. The polymer from Enterococcus hirae was of a higher molecular weight. This procedure was used to examine the effect of penicillin and chloramphenicol on the synthesis, turnover, and heterogeneity of LTA in S. agalactiae. Penicillin appeared to enhance LTA synthesis while causing the release of this polymer into the supernatant fluid. In contrast, chloramphenicol inhibited the synthesis of this molecule and resulted in its depletion from the cell surface. Penicillin did not alter the heterogeneity of this polymer, but chloramphenicol caused an apparent shift to a lower-molecular-weight from of the LTA, as determined by PAGE. This shift in the heterogeneity of LTA did not appear to be due to increased carbohydrate substitution, since chloramphenicol did not alter the electrophoretic migration profile of LTA from E. hirae. From a pulse-chase study, it was determined that LTA was released as a consequence of deacylation.
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17
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Mattingly SJ, Maurer JJ, Eskew EK, Cox F. Identification of a high-virulence clone of serotype III Streptococcus agalactiae by growth characteristics at 40 degrees C. J Clin Microbiol 1990; 28:1676-7. [PMID: 2199528 PMCID: PMC268017 DOI: 10.1128/jcm.28.7.1676-1677.1990] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A high-virulence clone of serotype III Streptococcus agalactiae causing invasive neonatal disease was previously identified by multilocus enzyme electrophoresis. A simple procedure involving growth at 40 degrees C distinguished all isolates classified in this high-virulence clone from other serotype III isolates, which are more frequently associated with asymptomatically colonized infants, as well as the other serotypes of group B streptococci. The high-virulence clone failed to grow at 40 degrees C in FMC, a chemically defined medium, in contrast to the other organisms, which grew readily.
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Affiliation(s)
- S J Mattingly
- Department of Microbiology, University of Texas Health Science Center, San Antonio 78284
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18
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Maurer JJ, Mattingly SJ. In vitro method to differentiate isolates of type III Streptococcus agalactiae from symptomatic and asymptomatic patients. J Clin Microbiol 1988; 26:686-91. [PMID: 3284898 PMCID: PMC266412 DOI: 10.1128/jcm.26.4.686-691.1988] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Streptococcus agalactiae (group B streptococci) isolates from infected infants have been demonstrated to have three- to fourfold or higher levels of cell-associated lipoteichoic acid than isolates from asymptomatically colonized infants, suggesting a role for this cell surface polymer in the relative virulence of these organisms. The present study indicates that symptomatic isolates of type III group B streptococci can be readily differentiated from asymptomatic strains by their response to various levels of phosphate in a chemically defined medium (FMC). Both classes of isolates had the same doubling time (TD of 30 to 35 min) in FMC containing 65 mM sodium phosphate. However, levels of phosphate greater than 125 mM distinguished the two classes of strains. Asymptomatic strains pregrown in 65 mM phosphate to the stationary phase rapidly initiated growth at elevated phosphate levels, while symptomatic strains initiated growth only after a prolonged incubation period (greater than 400 min). These results suggest that the physiological growth response of clinical isolates of group B streptococci to phosphate can serve as a diagnostic aid in screening potentially virulent strains in pregnant women and newborn infants.
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Affiliation(s)
- J J Maurer
- Department of Microbiology, University of Texas Health Science Center, San Antonio 78284
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19
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Mattingly SJ, Johnston BP. Comparative analysis of the localization of lipoteichoic acid in Streptococcus agalactiae and Streptococcus pyogenes. Infect Immun 1987; 55:2383-6. [PMID: 3308704 PMCID: PMC260717 DOI: 10.1128/iai.55.10.2383-2386.1987] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The cellular locations of deacylated lipoteichoic acid (dLTA) and lipoteichoic acid (LTA) were examined in late-exponential-phase cells of a serotype III strain of Streptococcus agalactiae (group B streptococci [GBS]) isolated from an infant with late-onset meningitis and compared with a fresh clinical isolate of Streptococcus pyogenes (group A streptococci [GAS]). LTA and dLTA were found to be associated with the protoplast membranes of both organisms, with only dLTA found in mutanolysin cell wall digests. Both organisms released dLTA during growth, but only the GAS released substantial levels of LTA into the culture medium. However, penicillin treatment (5 micrograms/ml for 60 min) of GBS resulted in the recovery of LTA in cell wall digests as well as in the culture medium. These results suggest that under normal growth conditions, the hydrophobic region (glycolipid) of LTA remains associated with the cytoplasmic membrane of GBS and unavailable for hydrophobic interactions at the cell surface with epithelial cells. In contrast, release of LTA into the environment by the GAS allows the fatty acid moieties to interact with hydrophobic domains on the surface of epithelial cells. These results may help explain the marked differences in the specificity of binding between these two major streptococcal pathogens for human fetal and adult epithelial cells.
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Affiliation(s)
- S J Mattingly
- Department of Microbiology, University of Texas Health Science Center at San Antonio 78284
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20
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Slifkin M, Cumbie R. Identification of group B streptococcal antigen with lectin-bound polystyrene particles. J Clin Microbiol 1987; 25:1172-5. [PMID: 3301888 PMCID: PMC269170 DOI: 10.1128/jcm.25.7.1172-1175.1987] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The lectin of the tomato, Lycopersicon esculentum, or of the potato, Solanum tuberosum, can be passively coupled to amide-modified polystyrene spheres to be used as a detection reagent for the specific identification of group B streptococcal cultures grown in selective or nonselective Todd-Hewitt broth for 5 and 4 h, respectively. Agglutination occurred when the lectin reagents were allowed to react with either the cell suspension, clarified broth, or antigen extracts from group B streptococci grown in Todd-Hewitt broth. No agglutination occurred when these lectins were allowed to react with strains of serogroup A, C, D, F, or G streptococci. False-negative agglutination responses may occur with certain serotype of group B streptococci grown on Columbia sheep blood agar. A 20-min staining time permitted the specific labeling of fixed smears of group B streptococci with fluorescein-conjugated Lycopersicon lectin. The lectin from the solanaceous plant Datura stramonium did not agglutinate group B streptococci or other clinically significant streptococcal serogroups.
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21
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Straus DC, Brown JG, Garner CW. High-density and low-density capsule production byStreptococcus zooepidemicus. Curr Microbiol 1987. [DOI: 10.1007/bf01568161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Covalent linkage of the type- and group-specific antigens to the peptide moiety of the peptidoglycan of serotype III group BStreptococcus. Curr Microbiol 1986. [DOI: 10.1007/bf01568519] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Blanco JD, Gibbs RS, Krebs LF. Inhibition of group B streptococci by amniotic fluid from patients with intra-amniotic infection and from control subjects. Am J Obstet Gynecol 1983; 147:247-50. [PMID: 6353921 DOI: 10.1016/0002-9378(83)91105-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This study describes the inhibition of group B streptococci by amniotic fluid from 50 patients with intra-amniotic infection and 50 matched, noninfected control subjects. Patients were matched for gestational age, time from rupture of membranes to delivery, and time from rupture of membranes to collection of the sample of fluid. Study patients had the clinical diagnosis of intra-amniotic infection and greater than or equal to 10(2) colony-forming units of a high-virulence organism per milliliter. None of the control patients became infected or received antibiotics. We collected the amniotic fluid in the study patients prior to antibiotic therapy. A comparison of bacterial growth in the amniotic fluid versus the amniotic fluid plus phosphate showed that only eight (16%) of the intra-amniotic infection samples of fluid were inhibitory, whereas 18 (36%) of the control samples of fluid were inhibitory (X2 = 5.20, p less than 0.02). However, a comparison of group B streptococci growth in amniotic fluid and Todd-Hewitt broth did not show a statistically significant difference. We conclude that the amniotic fluid bacterial inhibitory assay with group B streptococci is technically more difficult to perform and interpret.
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Durham DL, Straus DC. Extracellular products of type IIIStreptococcus agalactiae and their relationship to virulence. Curr Microbiol 1983. [DOI: 10.1007/bf01566964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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Doran TI, Mattingly SJ. Association of type- and group-specific antigens with the cell wall of serotype III group B streptococcus. Infect Immun 1982; 36:1115-22. [PMID: 7047392 PMCID: PMC551446 DOI: 10.1128/iai.36.3.1115-1122.1982] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The type-specific antigens (TSA) of group B streptococcus (GBS) represent the primary virulence factors for these organisms, yet little is known about their relationship to the cell surface of GBS. Crude cell walls of serotype III GBS strain 110 were purified by extraction with sodium dodecyl sulfate, LiCl, and urea, which removed essentially all of the protein associated with the cell wall as determined by amino acid analysis. Only those amino acids found in peptidoglycan were present, which included alanine, lysine, and glutamate (3.5:1:1 molar ratio). In contrast, these procedures resulted in the release of only 4.6% of the wall-associated TSA, indicating that protein was not the primary means by which TSA was bound to the cell surface. Mutanolysin (20 micrograms/ml) treatment of purified cell walls resulted in the release of 95% of the wall-associated TSA. The covalent association of TSA, the group B polysaccharide, and the peptidoglycan was demonstrated by the presence of N-acetylmuramic acid, rhamnose, alanine, glutamate, and lysine in mutanolysin-extracted TSA material purified by DEAE-Sephacel anion exchange and Sepharose 4B gel chromatography. Chemical analysis of purified cell walls revealed that group B antigen and peptidoglycan comprised 37.4 and 36.5%, respectively, whereas TSA accounted for 22.1 to 24.5% of the weight of the purified walls. Of the total 283.5 mg of TSA produced per 10-liter culture of GBS strain 110, 8.4% was released into the supernatant fluid. The remainder (249 mg) comprised the cell wall antigen. As described above, 4.6% of the cell wall antigen was extractable by nonenzymatic methods, which represented 3.8% of the total TSA, whereas 87.8% of the total TSA produced appeared to be covalently attached to the cell wall.
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Durham DL, Mattingly SJ, Doran TI, Milligan TW, Straus DC. Correlation between the production of extracellular substances by type III group B streptococcal strains and virulence in a mouse model. Infect Immun 1981; 34:448-54. [PMID: 7030959 PMCID: PMC350887 DOI: 10.1128/iai.34.2.448-454.1981] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Twelve strains of serotype III group B streptococci (8 isolated from cases of neonatal disease, 3 isolated from asymptomatically colonized infants, and 1 laboratory reference strain) were examined for the vitro production of three potential extracellular virulence products: type-specific antigen, neuraminidase, and protease. In addition, virulence in a mouse model, expressed as 50% lethal dose, was determined for the 12 strains to determine whether a relationship existed between the production of any of the three extracellular products and virulence. Only production of extracellular type-specific antigen showed a correlation with virulence in the mouse model. The high producers of extracellular type-specific antigen were an average of 166-fold more virulent for mice than low producers of the same component. There was no correlation between virulence and either neuraminidase or protease production, nor was there a correlation between either of these two extracellular products and the levels of extracellular type-specific antigen. When levels of group B streptococci of each type (a high and low producer of extracellular type-specific antigen) in organs of infected mice were examined, comparable levels of organisms were found in the brain, spleen, and lungs of mice near death regardless of the initial inoculum. However, the high producer of extracellular type-specific antigen caused death in mice with a 2 to 3 log lower inoculum than the low producer, suggesting that these strains may be more invasive.
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Doran TI, Straus DC, Mattingly SJ. Factors influencing release of type III antigens by group B streptococci. Infect Immun 1981; 31:615-23. [PMID: 7012015 PMCID: PMC351353 DOI: 10.1128/iai.31.2.615-623.1981] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The release of serotype III group B streptococcal polysaccharides into the supernatant fluid was examined under a variety of physiological conditions. Release of both high- and low-molecular-weight type III antigens was fairly constant throughout exponential growth, but increased markedly upon entering the stationary phase of growth. Increased glucose and decreased phosphate concentrations both caused a large increase in release of antigens. Inhibition of protein synthesis in exponentially growing cells by chloramphenicol (10 micrograms/ml) caused a condition of unbalanced growth in which antigen release was increased greatly over control values. Strain variability in antigen release was also observed. Strains which are known to be high neuraminidase producers released elevated levels of both low- and high-molecular-weight type III antigens. Non-neuraminidase-producing strains released considerably less high-molecular-weight antigen, but similar levels of the low-molecular-weight antigen compared with the high neuraminidase producers. Strain D136C, a type III non-neuraminidase producer, released negligible quantities of the high-molecular-weight antigen in the supernatant fluid. These results indicate that both the physiological environment and the type III strain are important in determining the quantity of type-specific antigen released into the culture fluid.
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Abstract
Two sialic acid-containing type III group B streptococcal antigens were obtained from a supernatant growth medium, purified by anion exchange or gel filtration, and found to be free of group B reactivity. Quantitation of the high-molecular-weight extracellular type III antigen indicated that approximately 20-fold more antigen was recoverable from the growth medium than could be obtained by neutral buffer extraction of whole cells.
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29
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Milligan TW, Baker CJ, Straus DC, Mattingly SJ. Association of elevated levels of extracellular neuraminidase with clinical isolates of type III group B streptococci. Infect Immun 1978; 21:738-46. [PMID: 361576 PMCID: PMC422060 DOI: 10.1128/iai.21.3.738-746.1978] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The level of total extracellular neuraminidase produced by 74 clinical isolates of group B streptococci isolated from diseased or asymptomatically colonized infants was assayed. Extracellular neuraminidase was obtained from concentrated filtrates of exponentially growing cultures of group B streptococci grown in a chemically defined medium (FMC) containing supplemental protein. The total activity of extracellular enzyme produced by these clinical isolates ranged from less than 10 to 360 nmol of sialic acid released per min per mg of cell dry weight. Strains were arbitrarily classified as either nonproducers (less than 10 nmol/min per mg of cell dry weight), low producers (greater than 10 to less than or equal 140 nmol/min per mg of cell dry weight), or high producers (greater than 140 to 360 nmol/min per mg of cell dry weight). Type III isolates from diseased infants were significantly more often classified as high producers than strains of group B streptococci of other serotypes from diseased infants (P less than 0.001). Furthermore, the serotype III strains isolated from neonatal infections were more often high producers than those of the same serotype from asymptomatically colonized infants (P less than 0.025). These results suggest that the ability to produce elevated levels of neuraminidase may be related to the frequent association of type III strains with disease among neonates.
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