Haemolytic activity of the `Streptococcus milleri group' and relationship between haemolysis restricted to human red blood cells and pathogenicity in S. intermedius

Jacobs, Jan; Schot, Corrie S.; Schouls, Leo M.

doi:10.1099/0022-1317-49-1-55

Cited by 22 publications

(24 citation statements)

References 19 publications

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“…Among the factors that might explain the tendency for abscess formation, the cytotoxic intermedilysin has been demonstrated to be a significant contributing factor (12). Intermedilysin production is confined to the species S. intermedius, which is more frequently associated with abscess formation than S. anginosus and S. constellatus (4,7,8). However, in our study the majority of SAG isolates persisting in abscesses were identified as S. anginosus and S. constellatus.…”

Section: Discussioncontrasting

confidence: 44%

“…The observation of identical or distinct AFLP types in single patients was supported by identification to the 16S rRNA ribogroup level (8,9) and by phenotypic characteristics such as the pattern of hemolysis and Lancefield group (results not shown).…”

Section: Reproducibility and Discriminatory Index By Aflp Analysismentioning

confidence: 77%

“…Species identification was performed by the 16S rRNA reverse line blot hybridization assay. The previously described S. intermedius non-exclusive human hemolytic strains were assigned to the species S. constellatus (8), and the isolates within the S. anginosus species with different 16S rRNA groups were grouped together (9). Consecutively obtained isolates for which there were 7 or more days between the dates of first and subsequent recoveries were selected from the collection of isolates recovered from 1993 to 2000.…”

Section: Methodsmentioning

confidence: 99%

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Genotyping by Amplified Fragment Length Polymorphism Analysis Reveals Persistence and Recurrence of Infection with Streptococcus anginosus Group Organisms

Jacobs¹,

Tjhie²,

Smeets³

et al. 2003

J Clin Microbiol

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Streptococcus anginosus, Streptococcus constellatus, and Streptococcus intermedius, commonly referred to as the Streptococcus anginosus group (SAG), are commensal organisms known for their propensity to cause purulent infections which are difficult to eradicate. In this study, we determined the genetic similarities between SAG isolates consecutively recovered from single patients to assess the duration of infection or colonization. A total of 97 SAG isolates recovered from 30 patients were included; 65 (67.0%) of the isolates were abscess related. The isolates were identified by the 16S rRNA reverse line blot hybridization assay as S. anginosus (n ‫؍‬ 34), S. constellatus (n ‫؍‬ 55), and S. intermedius (n ‫؍‬ 8). Amplified fragment length polymorphism (AFLP) analysis of the SAG isolates produced discriminatory and reproducible patterns. Consecutive SAG isolates with identical AFLP types were found in 27 of 30 (90.0%) patients, and consecutive isolates with only a single AFLP type were demonstrated in 21 (70.0%) patients. The median delay between the times of recovery of the first and last isolates of identical AFLP types from each patient was 36 days, and this delay extended for more than 1 year in patients with both colonizing and abscess-related SAG isolates. In six bacteremic patients, paired blood and nonblood SAG isolates showed identical AFLP types. Streptococcus anginosus, Streptococcus constellatus, andStreptococcus intermedius are commonly referred to as the Streptococcus milleri group, recently designated the Streptococcus anginosus group (SAG) (10). SAG strains are known for their association with purulent infections that occur after local disruption of the mucosal barrier, such as in cases of ulceration, perforation, inflammation, or surgery (6, 14). These infections often cause significant morbidity and may require repeat drainage procedures (6). In our collection of consecutive clinical SAG isolates, we observed successive isolates from patients with persistent or recurrent infections. Although biochemical and serological data pointed to a close similarity of at least some of the isolates recovered from single patients, information on relatedness at the genetic level was lacking. To study the genetic similarities between these successive SAG isolates, we used amplified fragment length polymorphism (AFLP) analysis (19). MATERIALS AND METHODSBacterial strains. SAG isolates were consecutively collected from clinical specimens routinely submitted for culture to the Medical Microbiology Department of the University Hospital Maastricht, a 600-bed tertiary-care hospital. Culture, isolation, and identification to the SAG level have been described previously (7). Species identification was performed by the 16S rRNA reverse line blot hybridization assay. The previously described S. intermedius non-exclusive human hemolytic strains were assigned to the species S. constellatus (8), and the isolates within the S. anginosus species with different 16S rRNA groups were grouped together (9). Consecutively obtained ...

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Section: Discussioncontrasting

confidence: 44%

Section: Reproducibility and Discriminatory Index By Aflp Analysismentioning

confidence: 77%

Section: Methodsmentioning

confidence: 99%

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Genotyping by Amplified Fragment Length Polymorphism Analysis Reveals Persistence and Recurrence of Infection with Streptococcus anginosus Group Organisms

Jacobs¹,

Tjhie²,

Smeets³

et al. 2003

J Clin Microbiol

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“…In addition, S. intermedius forms more than one cluster (Fig. 3A and B) (19). The heterogeneity may be explained by recombination, which has been shown in the 16S rRNA gene for this group (38).…”

Section: Discussionmentioning

confidence: 99%

Identification of 43 Streptococcus Species by Pyrosequencing Analysis of the rnpB Gene

et al. 2005

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Pyrosequencing technology was evaluated for identification of species within the Streptococcus genus. Two variable regions in the rnpB gene, which encodes the RNA subunit of endonuclease P, were sequenced in two reactions. Of 43 species, all could be identified to the species level except strains of the species pairs Streptococcus anginosus/S. constellatus and S. infantis/S. peroris. A total of 113 blood culture isolates were identified by pyrosequencing analysis of partial rnpB sequences. All but eight isolates could be unambiguously assigned to a specific species when the first 30 nucleotides of the two regions were compared to an rnpB database comprising 107 streptococcal strains. Principal coordinate analysis of sequence variation of strains from viridans group streptococci resulted in species-specific clusters for the mitis and the salivarius groups but not for the anginosus group. The identification capacity of pyrosequencing was compared to the biochemical test systems VITEK 2 and Rapid ID 32 Strep. The concordance between pyrosequencing and VITEK 2 was 75%, and for Rapid ID 32 Strep the corresponding figure was 77%. Isolates with discrepant identifications in the three methods were subjected to entire rnpB DNA sequence analysis that confirmed the identifications by pyrosequencing. In conclusion, pyrosequencing analysis of the rnpB gene can reliably identify Streptococcus species with high resolution.Species identification by molecular methods is emerging in the field of microbiological diagnostics and the demand for simple, sensitive, specific, and robust tests is increasing. Broad range identification methods are needed for genera with a large number of species. The genus Streptococcus is a diverse group of approximately 50 species, including many important pathogens for humans and domesticated animals. Current means of classification rely on manual or automated phenotypic test systems, but up to 25% of examined streptococcal strains are incorrectly or ambiguously identified (13, 24). The misidentifications occur because of phenotypic trait variability among strains within a given species (3) and inconsistency in biochemical traits of the same strain (41). Small alterations in manual procedures of the tests may also give false results.Several DNA-based methods have been evaluated for species identification of streptococci. DNA hybridization has been successfully used for detection of few species (4, 18) but has a limited use in broad range identification. Streptococcal species can be identified by measuring the tRNA intergenic lengths (8) and up to 31 species were distinguishable when the fragments were separated by capillary electrophoresis (2). Size separation can also be used for species identification when combined with amplification of selected targets (11, 23), arbitrarily primed PCR (33), and restriction of amplified rRNA genes (21, 37). The latter can discriminate a large number of species, but in all of these methods the identification is based on complex band patterns with limitations in resol...

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“…ILY is a member of the cholesterol-dependent cytolysins (CDC) which include streptolysin O (SLO) (4,19), and it has been shown to directly cause cell membrane damage in human erythrocytes and in cell lines derived from the major organs involved in deep-seated infections by S. intermedius (25). Therefore, ILY has been suggested as a potentially important virulence factor of this species (17,25). It has also been shown that the production level of ILY in isolates from deep-seated abscesses is 6.2-10.2-fold higher than in strains from normal habitats such as dental plaque, although no differences in production levels of other potential virulence factors such as hyaluronidase and sialidase were found (27).…”

mentioning

confidence: 99%

Intermedilysin Is Essential for the Invasion of Hepatoma HepG2 Cells by Streptococcus intermedius

Sukeno

Nagamune

Whiley

et al. 2005

Microbiology and Immunology

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Streptococcus intermedius is a member of the Anginosus group streptococci (AGS), which form part of the normal oral, urogenital and gastrointestinal microflora. AGS are recognized as opportunistic pathogens that cause purulent infection and abscess formation (6,16,32,(37)(38)(39). Notably, S. intermedius is an important pathogen of humans frequently causing deep-seated infections including abscesses in the brain and liver (38,39 Abstract: Streptococcus intermedius causes endogenous infections leading to abscesses. This species produces intermedilysin (ILY), a human-specific cytolysin. Because of the significant correlation between higher ILY production levels by S. intermedius and deep-seated abscesses, we constructed ily knockout mutant UNS38 B3 and complementation strain UNS38 B3R1 in order to investigate the role of ILY in deep-seated infections. Strain UNS38 reduced the viability of human liver cell line HepG2 at infection but not of rat liver cell line BRL3A. Isogenic mutant strain UNS38 B3 was not cytotoxic in either cell line. Quantification of S. intermedius revealed that in infected HepG2 cells UNS38 but not UNS38 B3 increased intracellularly concomitantly with increasing cell damage. This difference between UNS38 and UNS38 B3 was not observed with UNS38 B3R1. Invasion and proliferation in BRL3A cells was not observed. Masking UNS38 or UNS38 B3R1 with ILY antibody drastically decreased adherence and invasion of HepG2. Moreover, coating strain UNS38 B3 with ILY partially restored adherence to HepG2 but without subsequent bacterial growth. At 1 day post-infection, many intact UNS38 were detected in the damaged phagosomes of HepG2 with bacterial proliferation observed in the cytoplasm of dead HepG2 after an additional 2 day incubation. These results indicate that surface-bound ILY on S. intermedius is an important factor for invasion of human cells by this bacterium and that secretion of ILY within host cells is essential for subsequent host cell death. These data strongly implicate ILY as an important factor in the pathogenesis of abscesses in vivo by this streptococcus.

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Haemolytic activity of the `Streptococcus milleri group' and relationship between haemolysis restricted to human red blood cells and pathogenicity in S. intermedius

Cited by 22 publications

References 19 publications

Genotyping by Amplified Fragment Length Polymorphism Analysis Reveals Persistence and Recurrence of Infection with Streptococcus anginosus Group Organisms

Genotyping by Amplified Fragment Length Polymorphism Analysis Reveals Persistence and Recurrence of Infection with Streptococcus anginosus Group Organisms

Identification of 43 Streptococcus Species by Pyrosequencing Analysis of the rnpB Gene

Intermedilysin Is Essential for the Invasion of Hepatoma HepG2 Cells by Streptococcus intermedius

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