A case of culture-negative endocarditis due to Streptococcus tigurinus

Kanamori, Hajime; Kakuta, Risako; Yano, Hisakazu; Suzuki, Tomoyuki; Gu, Yoshiaki; Oe, Chihiro; Inomata, Shinji; Aoyagi, Tetsuji; Hatta, Mochammad; Endo, Shiro; Tokuda, Koichi; Weber, David J.; Nakamura, Yasuhiro; Saiki, Yoshikatsu; Kaku, Mitsuo

doi:10.1016/j.jiac.2014.08.014

Cited by 11 publications

(12 citation statements)

References 15 publications

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“…Other invasive infections included spondylodiscitis, prosthetic joint infections, meningitis, encephalitis, and empyema (16). Others have subsequently reported similar severe infections in patients from Korea (17), Japan (18), and the United States (19). The high virulence potential of this organism has been demonstrated in a rat model of endocarditis wherein it was demonstrated that S. tigurinus strains have increased abilities to resist macrophage-mediated phagocytosis and to invade endothelial cells (20).…”

Section: Gram-positive Coccimentioning

confidence: 95%

What's in a Name? New Bacterial Species and Changes to Taxonomic Status from 2012 through 2015

Munson

Carroll

2017

J Clin Microbiol

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Technological advancements in fields such as molecular genetics and the human microbiome have resulted in an unprecedented recognition of new bacterial genus/species designations by the International Journal of Systematic and Evolutionary Microbiology. Knowledge of designations involving clinically significant bacterial species would benefit clinical microbiologists in the context of emerging pathogens, performance of accurate organism identification, and antimicrobial susceptibility testing. In anticipation of subsequent taxonomic changes being compiled by the Journal of Clinical Microbiology on a biannual basis, this compendium summarizes novel species and taxonomic revisions specific to bacteria derived from human clinical specimens from the calendar years 2012 through 2015.KEYWORDS anaerobes, bacteria, Gram-negative bacteria, Gram-positive bacteria, taxonomy H uman microbiome studies, particularly those involving genome sequencing, have resulted in a seeming explosion of novel bacterial taxonomy. While many of these organisms appear to play a commensal role in site-specific ecology, some of the organisms may be of clinical significance in various patient populations. Moreover, enhanced studies of known bacterial genomes in a variety of applications, including those of an epidemiologic nature, have given rise to revisions and amendments to accepted bacterial taxonomy. Summaries of microbial taxonomy updates, such as those introduced in this edition of the Journal of Clinical Microbiology, are essential to routine practice in the clinical microbiology laboratory.Since 2014, laboratories subscribing to the College of American Pathologists accreditation program have encountered checklist standard MIC.11375 in the context of biennial inspection exercises. The standard (1) requires laboratories to assimilate "taxonomic changes that potentially affect the choice of appropriate antimicrobials to report and/or the interpretative breakpoints to use." Cited as an example for the context of this standard is the Gram-negative bacillus with the former taxonomic designation Actinobacillus actinomycetemcomitans. The taxonomic revision in 1985 (2) resulting in organism classification within the genus Haemophilus subsequently enabled antimicrobial susceptibility testing of clinically significant isolates using standards outlined in Table 2E of CLSI supplement M100S (example provided in [3]). Haemophilus test medium, with a 16-to 18-hour incubation in 5% CO 2 enrichment, could be utilized for disk diffusion. Haemophilus test medium broth could also be inoculated for broth microdilution testing with 20-to 24-hour incubation in ambient air.Subsequent reclassification of this organism into the genus Aggregatibacter (4) has resulted in the transition of susceptibility testing guidelines to those specific to (former) HACEK group organisms (Aggregatibacter spp., Cardiobacterium spp., Eikenella corrodens, and Kingella spp.) in Table 9 of the CLSI guideline M45 (5).

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Section: Gram-positive Coccimentioning

confidence: 95%

What's in a Name? New Bacterial Species and Changes to Taxonomic Status from 2012 through 2015

Munson

Carroll

2017

J Clin Microbiol

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“…Streptococcus tigurinus is a recently discovered oral pathogen, which is able to cause infective endocarditis, meningitis, and spondylodiscitis [8–10]. After the first isolates (AZ_3a [type strain, synonym DSM 24864], AZ_1-AZ_15) were described in Zürich, Switzerland, in 2012 [10], additional S. tigurinus isolates were found again in Switzerland (strain 1366 with small colony variants nos.…”

Section: Introductionmentioning

confidence: 99%

“…After the first isolates (AZ_3a [type strain, synonym DSM 24864], AZ_1-AZ_15) were described in Zürich, Switzerland, in 2012 [10], additional S. tigurinus isolates were found again in Switzerland (strain 1366 with small colony variants nos. 2425 and 2426), in Japan (two isolates of infective endocarditis [11]), in India (single isolate from the oral cavity of a periodontitis patient [12]), again in Switzerland (several isolates from the oral cavity [13], again in Japan (culture-negative endocarditis case [8] and one from bacteremia [14]), in Spain (endocarditis case [15]), in France (two endocarditis cases [16]), and in Washington, USA, where 14 isolates were recovered from numerous body sides, expanding the spectrum of associated diseases [17]. Up to November 2016, seven S. tigurinus genome sequences (strains AZ_3a, 1366, 2425, 2426, DGIIBVI and JPIBVI, UC5873) have been made accessible in GenBank [18–20].…”

Section: Introductionmentioning

confidence: 99%

Streptococcus tigurinus is frequent among gtfR-negative Streptococcus oralis isolates and in the human oral cavity, but highly virulent strains are uncommon

Conrads

Barth

Möckel

et al. 2017

Journal of Oral Microbiology

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Streptococcus tigurinus is a new member of the Mitis group and is associated with infective endocarditis. Low and high virulent variants have been described. A search was made in the national reference collection of endocarditis isolates for S. tigurinus –like strains by sequencing housekeeping genes (16S rRNA-gene, gdh, groEL, sodA ). The strains were further profiled by polymerase chain reaction (PCR) targeting a choice of virulence genes ( rib -like, cshA -like, gtfR, int, pitA, hylA ). To study the prevalence and abundance of S. tigurinus in the saliva and on the mucosal membranes of 35 healthy adults, PCRs detecting two variants of the 16S operon and virulence genes were applied. Among the endocarditis isolates, eight strains (all gtfR -negative and former S. oralis ) holding the specific S. tigurinus 16S motif were found, but the pattern of genes related to high virulence found in the S. tigurinus type strain could not be detected in any of these strains. A close phylogenetic proximity between S. tigurinus and S. oralis was observed, with intersectional hybrid strains formed. This was supported by concatenated housekeeping sequences, in silico DNA–DNA hybridization, pathogenomic profiling, and multidimensional scaling. In the oral samples, S. tigurinus could be detected frequently, especially in the most common operon variant, but none of the type strain–related virulence factors were found. Low virulent S. tigurinus –like strains can be found frequently and in high prevalence (66%) and abundance (12.5%) in the oral cavity of healthy adults. In strain collections, they are among the formerly known gtfR -negative S. oralis . Highly virulent strains seem to be uncommon. Though closely related, S. oralis and S. tigurinus can be separated by the presence or absence of gtfR and dextran production. Hybrids of both species can be found. The variable arsenal of virulence genes found in this study emphasizes the genetic plasticity of Mitis group streptococci.

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“…Since the first report of S. tigurinus infection in 2012, S. tigurinus has been isolated from several additional sterile sites, including cerebrospinal fluid, heart valves, and joint fluid (2,3). It has been associated with serious invasive infections, including infective endocarditis, culture-negative endocarditis, spondylodiscitis, bacteremia, meningitis, prosthetic joint infections, and thoracic empyema (2,4). Small colony variants of S. tigurinus were associated with a prosthetic joint infection (3).…”

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confidence: 99%

Clinical Significance and Characterization of Streptococcus tigurinus Isolates in an Adult Population

Bourassa

Clarridge

2015

J Clin Microbiol

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Streptococcus tigurinus is a newly described member of the Streptococcus mitis group. Due to the difficulty in distinguishing viridans group streptococci (VGS) by phenotype, analysis of 16S rRNA sequences is necessary for the accurate identification of most species. Through a laboratory policy of analyzing all clinically significant isolates from the VGS group by16S rRNA gene sequencing, we identified 14 S. tigurinus isolates from 11 patients. The Vitek 2 system most commonly gave an excellent rating to an incorrect identification (e.g., Streptococcus mitis), as did matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) (e.g., Streptococcus oralis). S. tigurinus strains were recovered from numerous body sites, including the blood, peritoneal fluid, bone, synovial fluid, a perianal abscess, and an arm wound. Retrospective chart review indicated that most isolates were clinically significant, with bacteremia (n ‫؍‬ 5), soft tissue infections (n ‫؍‬ 3) osteomyelitis (n ‫؍‬ 2), infected joint prosthesis (n ‫؍‬ 2), and peritonitis (n ‫؍‬ 2) being the most common, thus expanding the spectrum of disease associated with S. tigurinus. Streptococcus tigurinus was first described after isolation from a patient with infective endocarditis. Isolates of alpha-hemolytic, catalase-negative Gram-positive cocci were recovered from multiple blood cultures of a 74-year-old patient. The isolates were initially identified as viridans group streptococci (VGS). However, analysis of 16S rRNA sequences revealed that the isolates were distinct members of the Streptococcus mitis group (SMG) and were closely related to Streptococcus pneumoniae, Streptococcus pseudopneumoniae, Streptococcus mitis, Streptococcus infantis, and Streptococcus oralis (1). This novel Streptococcus strain was named Streptococcus tigurinus. Since the first report of S. tigurinus infection in 2012, S. tigurinus has been isolated from several additional sterile sites, including cerebrospinal fluid, heart valves, and joint fluid (2, 3). It has been associated with serious invasive infections, including infective endocarditis, culture-negative endocarditis, spondylodiscitis, bacteremia, meningitis, prosthetic joint infections, and thoracic empyema (2, 4). Small colony variants of S. tigurinus were associated with a prosthetic joint infection (3). S. tigurinus has also been isolated from the subgingival plaque of a patient with periodontitis (5). In vitro studies have shown S. tigurinus to be highly virulent in a rat model of experimental endocarditis (6).Because of its relatedness to SMG, S. tigurinus has been hypothesized to be a commensal of the human oral cavity. Data to support this hypothesis, however, are conflicting (7). In a screen of saliva specimens from 31 volunteers, S. tigurinus was not identified among the more than 600 strains of alpha-hemolytic bacterial colonies isolated (2). In a second study that used a specific 16S rRNA gene real-time TaqMan PCR assay, however, S. tigurinus was detected in the saliva and subgingiv...

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A case of culture-negative endocarditis due to Streptococcus tigurinus

Cited by 11 publications

References 15 publications

What's in a Name? New Bacterial Species and Changes to Taxonomic Status from 2012 through 2015

What's in a Name? New Bacterial Species and Changes to Taxonomic Status from 2012 through 2015

Streptococcus tigurinus is frequent among gtfR-negative Streptococcus oralis isolates and in the human oral cavity, but highly virulent strains are uncommon

Clinical Significance and Characterization of Streptococcus tigurinus Isolates in an Adult Population

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