Speciation of presumptive viridans streptococci from early onset neonatal sepsis

West, P. W. J.; Al-Sawan, Rimac; Foster, H. A.; Electricwala, Qudsiya; Alex, Aleyamma; Panigrahi, D

doi:10.1099/00222615-47-10-923

Cited by 13 publications

(9 citation statements)

References 19 publications

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“…Pneumococcus, groups C and G streptococci, as well as viridans streptococci clinical presentation is very similar to GBS infection and transmission seems to be secondary to bacterial colonization of the maternal genital tract. 47–51 Enterococcal EOS is usually mild compared to LOS and it is characterized by either a mild respiratory illness or diarrhea without a focal infection. Enterococcus faecalis is more frequently isolated than E. faecium and most of the isolates remain ampicillin susceptible.…”

Section: Early Onset Sepsismentioning

confidence: 99%

Neonatal Infectious Diseases

Camacho-González

Spearman

Stoll

2013

Pediatric Clinics of North America

373

143

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Synopsis Neonatal sepsis remains a feared cause of morbidity and mortality in the neonatal period. Maternal, neonatal and environmental factors are associated with risk of infection, and a combination of prevention strategies, judicious neonatal evaluation and early initiation of therapy are required to prevent adverse outcomes. The following chapter reviews recent trends in epidemiology, and provides an update on risk factors, diagnostic methods and management of neonatal sepsis.

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Section: Early Onset Sepsismentioning

confidence: 99%

Neonatal Infectious Diseases

Camacho-González

Spearman

Stoll

2013

Pediatric Clinics of North America

373

143

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“…The results of these and similar schemes have shown clearly that within the viridans streptococci, Streptococcus oralis is a significant agent of infective endocarditis and a major pathogen in patients with attenuated host defence mechanisms [6,10,[12][13][14]. The mechanisms by which S. oralis causes this wide range of infections are as yet unclear, but the sialidase produced by this bacterium has been proposed as contributing towards the pathogenicity of several other micro-organisms, including S. pneumoniae, Salmonella typhimurium and Vibrio cholerae [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Isolation and characterisation of sialidase from a strain of Streptococcus oralis

Byers¹,

Tarelli²,

Homer³

et al. 2000

Journal of Medical Microbiology

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Streptococcus oralis, the most virulent of the viridans streptococci, produces a sialidase and this exo-glycosidase has been implicated in the disease process of a number of pathogens. The sialidase of S. oralis strain AR3 was purified in order to understand the characteristics of this putative virulence determinant. The enzyme isolated as a high mol. wt aggregate (c. 325 kDa) was purified 4520-fold from late exponential phase cultures by a combination of ultrafiltration, ammonium sulphate precipitation, ionexchange and gel filtration chromatography. The sialidase component had a mol. wt of 144 kDa as determined by SDS-PAGE analysis. The purified sialidase released Nacetylneuraminic acid from a range of sialoglycoconjugates including human AE 1 -acid glycoprotein, bovine submaxillary mucin, colominic acid and sialyl-AE2,3-and sialyl-AE2,6-lactose. Also, N-glycolylneuraminic acid was cleaved from bovine submaxillary mucin. The sialidase had a K m of 11.8 ìM for AE 1 -acid glycoprotein, was active over a broad pH range with a pH optimum of 6.0 and cleaved AE2,3-, AE2,6-and AE2-8-sialyl glycosidic linkages with a marked preference for AE2,3-linkages. The enzyme was competitively inhibited by the sialic acid derivative, 2,3-dehydro-N-acetylneuraminic acid, with a K IC of 1.2 ìM. The characteristics of the purified sialidase would support a nutritional role for this enzyme that may be significant in the proliferation of this organism in the oral cavity and at extra-oral sites in association with life-threatening infections.

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“…Douglas and coworkers (13) documented that, out of 42 cases of infective endocarditis from which viridans group streptococci were isolated, the most common species were from the mitis group, namely, Streptococcus sanguis, S. oralis, and Streptococcus gordonii (isolation frequencies of 31.9, 29.8, and 12.7%, respectively). S. oralis is also the predominant species of the viridans group streptococci associated with septicemia in neutropenic patients (2) and neonates (33).…”

mentioning

confidence: 99%

Effect of Acidic pH on Expression of Surface-Associated Proteins of Streptococcus oralis

Wilkins

Beighton

Homer

2003

Appl Environ Microbiol

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Streptococcus oralis, a member of the mitis group of oral streptococci, is implicated in the pathogenesis of infective endocarditis and is the predominant aciduric non-mutans-group streptococcus in dental plaque. We undertook to identify the most abundant surface-associated proteins of S. oralis and to investigate changes in protein expression when the organism was grown under acidic culture conditions. Surface-associated proteins were extracted from cells grown in batch culture, separated by two-dimensional gel electrophoresis, excised, digested with trypsin, and analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry and liquid chromatography-tandem mass spectrometry. Putative functions were assigned by homology to a translated genomic database of Streptococcus pneumoniae. A total of 27 proteins were identified; these included a lipoprotein, a ribosome recycling factor, and the glycolytic enzymes phosphoglycerate kinase, fructose bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, and enolase. The most abundant protein, phosphocarrier protein HPr, was present as three isoforms. Neither lactate dehydrogenase nor pyruvate oxidase, dominant intracellular proteins, were present among the proteins on the gels, demonstrating that proteins in the surface-associated pool did not arise as a result of cell lysis. Eleven of the proteins identified were differentially expressed when cells were grown at pH 5.2 versus pH 7.0, and these included superoxide dismutase, a homologue of dipeptidase V from Lactococcus lactis, and the protein translation elongation factors G, Tu, and Ts. This study has extended the range of streptococcal proteins known to be expressed at the cell surface. Further investigations are required to ascertain their functions at this extracellular location and determine how their expression is influenced by other environmental conditions.Streptococcus oralis, a member of the mitis group of the viridans group streptococci, is a component of normal dental plaque, in which it forms a significant proportion of the aciduric microflora (5, 34). Aciduricity, the ability to grow under conditions of low pH, is considered a virulence determinant for bacteria associated with the initiation and progression of dental caries, although the precise role of S. oralis in this disease process has yet to be fully defined. In addition to the potential role of S. oralis in dental caries, it is well documented that S. oralis is associated with a range of extraoral diseases including endocarditis and infections in susceptible patients, including those who are immunologically compromised. Douglas and coworkers (13) documented that, out of 42 cases of infective endocarditis from which viridans group streptococci were isolated, the most common species were from the mitis group, namely, Streptococcus sanguis, S. oralis, and Streptococcus gordonii (isolation frequencies of 31.9, 29.8, and 12.7%, respectively). S. oralis is also the predominant species of the viridans group streptococci as...

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Speciation of presumptive viridans streptococci from early onset neonatal sepsis

Cited by 13 publications

References 19 publications

Neonatal Infectious Diseases

Neonatal Infectious Diseases

Isolation and characterisation of sialidase from a strain of Streptococcus oralis

Effect of Acidic pH on Expression of Surface-Associated Proteins of Streptococcus oralis

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