Biochemical and genetic characterization of serologically untypable <i>Streptococcus mutans</i> strains isolated from patients with bacteremia

Fujiwara, Taku; Nakano, Kazuhiko; Kawaguchi, Masashi; Ooshima, Takashi; Sobue, S; Kawabata, Shigetada; Nakagawa, Ichirô; Hamada, Shigeyuki

doi:10.1034/j.1600-0722.2001.00119.x

Cited by 45 publications

(59 citation statements)

References 26 publications

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“…The inability of certain strains to utilize b-glucosides is also associated with deletions in the bgl or cel genes (Old et al, 2006). Other researchers have reported that genes required for formation of serotypespecific polysaccharide are absent from untypable isolates (Fujiwara et al, 2001). There is also evidence for the existence of genes in some strains of S. mutans that are not found in UA159.…”

Section: Introductionmentioning

confidence: 74%

Dispensable genes and foreign DNA in Streptococcus mutans

Waterhouse¹,

Russell²

2006

Microbiology

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A range of properties, including the ability to utilize various sugars, bind macromolecules and produce mutacins, are known to vary in their occurrence in different strains of Streptococcus mutans. In addition, insertion-sequence elements show a limited distribution and sequencing of the genome of S. mutans UA159 has revealed the presence of putative genomic islands of atypical base composition indicative of foreign DNA. PCR primers flanking regions suspected of having inserted DNA were designed on the basis of the genome sequence of S. mutans UA159 and used to explore variation in a collection of 39 strains isolated in various parts of the world over the last 40 years. Extensive differences between strains were detected, and similar insertion/deletion events appear to be present in the genomes of strains with very different origins. In two instances, insertion of foreign DNA appears to have displaced original S. mutans genes. Together with previous results on the occurrence of deletions in genes associated with sugar metabolism, the results indicate that S. mutans has a core genome and a dispensable genome, and that dispensable genes have become widely distributed through horizontal transfer.

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Section: Introductionmentioning

confidence: 74%

Dispensable genes and foreign DNA in Streptococcus mutans

Waterhouse¹,

Russell²

2006

Microbiology

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Section: Methodsmentioning

confidence: 99%

“…The amplified fragments were visualized in 0.7 % agarose gel in the presence of 1 mg ethidium bromide ml 21 . For all detections, strains TW871 and MT8148 (Fujiwara et al, 2001;Ooshima et al, 1983) were used as positive and negative controls, respectively.Analysis of clonal relationship using MLST. One S. mutans strain possessing the cnm gene from each subject was randomly selected and analysed by the MLST scheme, as described previously (Nakano et al, 2007).…”

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confidence: 99%

Multilocus sequence typing analysis of Streptococcus mutans strains with the cnm gene encoding collagen-binding adhesin

Lapirattanakul

Nakano

Nomura

et al. 2011

Journal of Medical Microbiology

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Streptococcus mutans is one of the oral pathogens associated with infective endocarditis (IE).With respect to bacterial binding ability to the extracellular matrix, the Cnm protein, a cell surface collagen-binding adhesin of S. mutans, is known as one of the possible virulence factors with regard to IE. In this study, we aimed to determine the distribution of the cnm gene, which encodes Cnm, in a large number of clinical isolates of S. mutans from Thai subjects. Then, the cnm-positive strains were classified using a multilocus sequence typing (MLST) scheme, which we constructed previously. In addition, the data were analysed together with our previous MLST data of cnmpositive strains from Japan and Finland in order to evaluate the clonal relationship among S. mutans strains harbouring the cnm gene. The cnm gene was detected in 12.4 % of all 750 Thai isolates, and serotype f showed the highest rate of detection (54.5 %). According to the MLST data, two clonal complex groups were revealed as the important clones related to cnm-positive S. mutans from various origins of isolation. Moreover, the collagen-binding properties of S. mutans strains with the cnm gene were significantly greater than those of strains without the gene, although four cnm-negative strains classified into two sequence types (STs), ST110 and ST136, showed extremely high collagen-binding rates suggesting the presence of additional genes involved with collagen binding in these STs. Taken together, these results provided information on both epidemiological as well as evolutional aspects of S. mutans possessing the cnm gene. INTRODUCTIONStreptococcus mutans is a well-known pathogen of dental caries (Hamada & Slade, 1980), which consists of four serotypes, c, e, f and k (Linzer et al., 1986;). The detection rate of serotype c is highest among the strains isolated from oral cavities, followed by serotype e, while serotypes f and k are regarded as being present in minor proportions . Various pieces of evidence show the association of S. mutans with some life-threatening diseases such as infective endocarditis (IE), although the major species related to IE belong to the mitis group of oral streptococci (Banas, 2004;Mylonakis & Calderwood, 2001). Moreover, continuous detections of this bacterium in specimens from patients suffering from such disease emphasize the importance of S. mutans in IE (Gauduchon et al., 2001;Nomura et al., 2006;Vose et al., 1987;Ullman et al., 1988). Indeed, studies to clarify specific components involved in IE in S. mutans have also been performed worldwide (Beg et al., 2002;Jung et al., 2009; MatsumotoNakano et al., 2009;Miller-Torbert et al., 2008).IE is initiated by the binding of bacterial surface molecules to host extracellular matrix (ECM) proteins exposed on damaged heart tissue (Moreillon & Que, 2004). In S. mutans, collagen-binding adhesin or Cnm protein, encoded by the cnm gene, was reported as a strain-specific collagen-binding molecule (Sato et al., 2004). The Cnm protein possesses a collagen-binding domain (CBD) in ...

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“…The colony morphology of these strains on agar plates was apparently different from that of typical S. mutans strains, whereas it was similar to strains generated by inactivation of the genes encoding GTFs (Ooshima et al, 2001). As the occurrence of S. mutans without GTF expression is extremely rare in the oral cavity, we performed molecular characterization of the GTFs in the V1 strain isolated from the infected heart valve of this patient and speculate on its origin based on the results of strain-specific characterization.…”

Section: Introductionmentioning

confidence: 92%

“…The bacterium synthesizes adhesive glucan from sucrose by the action of three types of glucosyltransferase (GTF: GTFB, GTFC and GTFD), each of which, at an optimum ratio, has been shown to be important for sucrose-dependent adherence (Ooshima et al, 2001). GTFs are known to be important virulence factors of S. mutans for dental caries, as inactivation of the genes encoding each GTF results in a drastic reduction in caries-inducing activity in animal experiments (Yamashita et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of Streptococcus mutans strains isolated from the heart valve of an infective endocarditis patient

Nemoto

Nakano

Nomura

et al. 2008

Journal of Medical Microbiology

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Streptococcus mutans, known to be an aetiological agent of dental caries, is occasionally isolated from patients with infective endocarditis (IE). S. mutans strains with a defect in all three types of glucosyltransferase (GTF) obtained from an infected heart valve extirpated from an IE patient have been reported previously. In this study, molecular analyses of strains detected in heart valve (strain V1) and dental plaque (strain P1) samples taken from the same patient were performed. Complete nucleotide alignments of the gtfB, gtfC and gtfD regions in strains V1 and P1, as well as in the reference strain MT8148, were determined, which revealed the existence of alignments with a high similarity to erythromycin-and spectinomycin-resistance genes in the middle of the gtfBgtfC and gtfD genes, respectively, of V1. Strain V1 also showed a higher MIC for these two antibiotics compared with strain P1. Next, primers to detect the specific sequences of the antibiotic-resistance genes in strain V1 were constructed and PCR amplification was performed with template DNA from dental plaque and infected valve tissue samples taken from the patient. Attenuated expression of GTFs in V1 caused a significantly lower susceptibility to phagocytosis by human polymorphonuclear leukocytes compared with the reference strain. These results suggest that the blood isolate V1 found in the oral cavity invaded and survived in the bloodstream for a long duration and that this was related to its virulence in IE in our patient.

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Biochemical and genetic characterization of serologically untypable Streptococcus mutans strains isolated from patients with bacteremia

Cited by 45 publications

References 26 publications

Dispensable genes and foreign DNA in Streptococcus mutans

Dispensable genes and foreign DNA in Streptococcus mutans

Multilocus sequence typing analysis of Streptococcus mutans strains with the cnm gene encoding collagen-binding adhesin

Molecular characterization of Streptococcus mutans strains isolated from the heart valve of an infective endocarditis patient

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