scholarly journals In-vitro antimicrobial susceptibility of the ‘Streptococcus milleri’ group (Streptococcus anginosus, Streptococcus constellatus and Streptococcus intermedius)

1996 ◽  
Vol 37 (2) ◽  
pp. 371-375 ◽  
Author(s):  
Jan A. Jacobs ◽  
Ellen E. Stobberingh
Keyword(s):  
Antimicrobial Susceptibility ◽  
Streptococcus Intermedius ◽  
Streptococcus Anginosus ◽  
Streptococcus Constellatus ◽  
Streptococcus Milleri ◽  
Streptococcus Milleri Group

scholarly journals Antibiotic Susceptibilities of Genetically Characterized Streptococcus milleri Group Strains

2001 ◽  
Vol 45 (5) ◽  
pp. 1511-1514 ◽  
Author(s):  
Michael Tracy ◽  
Anna Wanahita ◽  
Yevgeny Shuhatovich ◽  
Elizabeth A. Goldsmith ◽  
Jill E. Clarridge ◽  
...  
Keyword(s):  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Beta Lactam ◽  
Streptococcus Anginosus ◽  
Beta Lactam Antibiotics ◽  
Streptococcus Constellatus ◽  
Antibiotic Susceptibilities ◽  
Streptococcus Milleri ◽  
Streptococcus Milleri Group ◽  
Rrna Gene Sequencing

ABSTRACT Previous studies of the antibiotic susceptibility ofStreptococcus milleri group organisms have distinguished among species by using phenotypic techniques. Using 44 isolates that were speciated by 16S rRNA gene sequencing, we studied the MICs and minimum bactericidal concentrations of penicillin, ampicillin, ceftriaxone, and clindamycin for Streptococcus intermedius, Streptococcus constellatus, and Streptococcus anginosus. None of the organisms was resistant to beta-lactam antibiotics, although a few isolates were intermediately resistant; one strain of S. anginosus was tolerant to ampicillin, and another was tolerant to ceftriaxone. Six isolates were resistant to clindamycin, with representation from each of the three species. Relatively small differences in antibiotic susceptibilities among species of the S. milleri group show that speciation is unlikely to be important in selecting an antibiotic to treat infection caused by one of these isolates.

scholarly journals A streptolysin S homologue is essential for β-haemolytic Streptococcus constellatus subsp. constellatus cytotoxicity

Microbiology ◽  
2014 ◽  
Vol 160 (5) ◽  
pp. 980-991 ◽  
Author(s):  
Atsushi Tabata ◽  
Yuji Sato ◽  
Kentaro Maya ◽  
Kota Nakano ◽  
Ken Kikuchi ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Pcr Amplification ◽  
Haemolytic Activity ◽  
Deletion Mutants ◽  
Streptococcus Intermedius ◽  
Streptococcus Anginosus ◽  
Streptolysin S ◽  
Streptococcus Constellatus ◽  
The Family ◽  
The Relationship

Streptococcus constellatus is a member of the Anginosus group streptococci (AGS) and primarily inhabits the human oral cavity. S. constellatus is composed of three subspecies: S. constellatus subsp. constellatus (SCC), S. constellatus subsp. pharyngis and the newly described subspecies S. constellatus subsp. viborgensis. Although previous studies have established that SCC contains β-haemolytic strains, the factor(s) responsible for β-haemolysis in β-haemolytic SCC (β-SCC) has yet to be clarified. Recently, we discovered that a streptolysin S (SLS) homologue is the β-haemolytic factor of β-haemolytic Streptococcus anginosus subsp. anginosus (β-SAA), another member of the AGS. Furthermore, because previous studies have suggested that other AGS species, except for Streptococcus intermedius, do not possess a haemolysin(s) belonging to the family of cholesterol-dependent cytolysins, we hypothesized that, as with β-SAA, the SLS homologue is the β-haemolytic factor of β-SCC, and therefore aimed to investigate and characterize the haemolytic factor of β-SCC in the present study. PCR amplification revealed that all of the tested β-SCC strains were positive for the sagA homologue of SCC (sagA SCC). Further investigations using β-SCC strain W277 were conducted to elucidate the relationship between sagA SCC and β-haemolysis by constructing sagA SCC deletion mutants, which completely lost β-haemolytic activity. This loss of β-haemolytic activity was restored by trans-complementation of sagA SCC. Furthermore, a co-cultivation assay established that the cytotoxicity of β-SCC was clearly dependent on the presence of sagA SCC. These results demonstrate that sagA SCC is the factor responsible for β-SCC β-haemolysis and cytotoxicity.

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