Presence of Streptococcus mutans strains harbouring the cnm gene correlates with dental caries status and IgA nephropathy conditions.

Taro Misaki,Shuhei Naka,Rina Hatakeyama,Kazuhiko Nakano,Ryota Nomura,Akiko Fukunaga,Taisuke Isozaki

doi:10.1038/srep36455

Taro Misaki, Shuhei Naka + Show 5 more

Open Access

https://doi.org/10.1038/srep36455

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Abstract

Streptococcus mutans is a major pathogen of human dental caries. Strains harbouring the cnm gene, which encodes Cnm, a collagen-binding protein, contribute to the development of several systemic diseases. In this study, we analysed S. mutans strains isolated from the oral cavity of immunoglobulin (Ig)A nephropathy (IgAN) patients to determine potential relationships between cnm and caries status as well as IgAN conditions. Saliva specimens were collected from 109 IgAN patients and the cnm status of isolated S. mutans strains was determined using PCR. In addition, the dental caries status (decayed, missing or filled teeth [DMFT] index) in patients who agreed to dental consultation (n = 49) was evaluated. The DMFT index and urinary protein levels in the cnm-positive group were significantly higher than those in the cnm-negative group (p < 0.05). Moreover, the urinary protein levels in the high DMFT (≥15) group were significantly higher than those in the low DMFT (<15) group (p < 0.05). Our results show that isolation of cnm-positive S. mutans strains from the oral cavity may be associated with urinary protein levels in IgAN patients, especially those with a high dental caries status.

Highlights

Background differences betweenS. mutans-negative groups and cnm-positive and cnm-negative S. mutans groups
We previously showed that the rate of cnm-positive S. mutans strains isolated from the oral cavity was found to be significantly higher in IgAN patients than in non-diseased controls, suggesting that the presence of cnm-positive S. mutans strains in the oral cavity may influence IgAN severity[18]
The present study clearly demonstrated that IgAN patients harbouring cnm-positive S. mutans strains in the oral cavity showed significantly higher DMFT index values and urinary protein levels compared with the cnm-negative S. mutans group

Summary

Introduction

Background differences betweenS. mutans-negative groups and cnm-positive and cnm-negative S. mutans groups. The association between % urinary protein 1+or higher and cnm-positive S. mutans in IgAN patients remained significantly different in subsequent logistic regression analysis adjusted for age and gender (p = 0.0011) (Supplementary Table S1). The cnm-positive S. mutans in the IgAN patients group was significantly associated with higher age, higher serum creatinine, lower estimated glomerular filtration rates (eGFR), % urinary occult blood 1+or higher and higher DMFT index These data did not remain significantly different in subsequent logistic regression analyses adjusted for age and gender (data not shown). The cnm-positive S. mutans group was significantly associated with lower eGFR (p = 0.0173) and higher renin-angiotensin system inhibitor (RAS-I) medication rates (p = 0.0444), these data did not remain significantly different in subsequent logistic regression analysis adjusted for age and sex (data not shown)

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Conclusion