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

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.

<b><i>Campylobacter rectus</i></b> in the Oral Cavity Correlates with Proteinuria in Immunoglobulin A Nephropathy Patients

“…Urinary protein excretion and urinary occult blood were significantly higher in the IgAN group than in the control group ( p < 0.0001). cnm -positive S. mutans was significantly more prevalent in the IgAN group than in the control group ( p < 0.05) as described in detail previously [23]. …”

“…Comparisons between cnm -positive and -negative S. mutans groups of IgAN patients were as described in detail previously [23]. The percentage of urinary protein 1+ or higher and urinary protein levels in the cnm -positive group were significantly higher than those in the cnm -negative group in IgAN patients ( p < 0.05) [23].…”

“…The percentage of urinary protein 1+ or higher and urinary protein levels in the cnm -positive group were significantly higher than those in the cnm -negative group in IgAN patients ( p < 0.05) [23]. …”

“…Our recent studies suggest that cnm -positive S. mutans strains could be associated with aggravated cerebral haemorrhaging [16-18], non-alcoholic steatohepatitis [19, 20] and inflammatory bowel disease [21]. We also demonstrated that cnm -positive S. mutans was associated with IgAN [22, 23]. …”

“…In this study, we investigated cnm -positive S. mutans in saliva specimens and clinical data of each subject as reported previously [23]. In addition, saliva specimens kept frozen at –20°C were used to evaluate the presence of C. rectus and T. denticola DNA by PCR as described previously [24].…”