Isolation ofStreptococcus tigurinus- a novel member ofStreptococcus mitisgroup from a case of periodontitis

Abstract

Streptococcus tigurinus is a new member of the Streptococcus viridians group and is closely related to Streptococcus mitis, Streptococcus pneumoniae, Streptococcus pseudopneumoniae, Streptococcus oralis, and Streptococcus infantis. The type strain AZ_3a(T) of S. tigurinus was originally isolated from a patient with infective endocarditis. Accurate identification of S. tigurinus is facilitated only by newer molecular methods like 16S rRNA gene analysis. During the course of study on bacteraemia and infective endocarditis with reference to periodontitis and viridians group of streptococci, a strain of S. tigurinus isolated from subgingival plaque of a patient with periodontitis identified by 16S rRNA gene analysis, which was originally identified as Streptococcus pluranimalium by Vitek 2. Confirmation by 16S rRNA gene analysis showed 99.39% similarity (1476/1485 bp) with S. tigurinus AZ_3a(T) (AORU01000002). To the best of our knowledge, this is the first report of isolation of S. tigurinus from the oral cavity of a periodontitis patient.

Analysis of Gastric Body Microbiota by Pyrosequencing: Possible Role of Bacteria Other ThanHelicobacter pyloriin the Gastric Carcinogenesis

“…in the HP(−) cancer group was more greater than the others (Table 2). The proportion of Streptococcus mitis group,20–22 such as S. pseudopneumoniae, S. mitis, S. infantis, S. oralis , and S. tigurinus , in the HP(−) cancer group was more higher than in that of the HP(+) cancer group (antrum, 33.9 vs. 8.4, P = 0.076; body, 34.1 vs. 0.33, P = 0.009; Table 2). These results suggest a role of S. mitis in the gastric carcinogenesis despite the absence of HP.…”

The novel speciesStreptococcus tigurinusand its association with oral infection

“…S. tigurinus not only was detected in patients with periodontitis but also in individuals without periodontal diseases. 41,53 Earlier studies have demonstrated that S. mitis, which is the closest related species to S. tigurinus, is a predominant early colonizing species of dental biofilms. 54 Although S. mitis is not a potent inducer of immune responses, it can antagonize the capacity of A. actinomycetemcomitans (a key pathogen associated with the localized aggressive form of periodontitis occurring in younger individuals) to stimulate IL-8.…”

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

“…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].…”