Detection of Cariogenic Streptococcus mutans in Extirpated Heart Valve and Atheromatous Plaque Specimens

Abstract

The involvement of oral bacteria in the pathogenesis of cardiovascular diseases has been the focus of attention in many studies, and several periodontal pathogens have been detected in diseased cardiovascular lesions, suggesting relationships between oral microorganisms and cardiovascular diseases. However, no information is available regarding the involvement of cariogenic pathogens such as Streptococcus mutans. The presence of oral streptococcal species and periodontitis-related bacteria in 35 heart valve and 27 atheromatous plaque clinical specimens, as well as 32 dental plaque specimens from the same subjects, was analyzed using a PCR method. Furthermore, broad-range PCR with DNA sequencing analysis was employed to identify the bacterial species in those samples. Streptococcus mutans was frequently detected in the heart valve (69%) and atheromatous plaque (74%) specimens, while other bacterial species, including those related to periodontitis, were detected with much lower frequencies. The bacterial composition in cardiovascular tissues was found to be markedly distinct from that in dental plaque, with only a limited number of species, including S. mutans, in the cardiovascular regions shown to have possibly originated from the oral cavity. Semiquantitative assay results revealed that S. mutans was detected in significant quantities in the heart valve (40%) and atheromatous plaque (48%) specimens, whereas the quantities of all other tested bacterial species, including several related to periodontitis, were negligible in the cardiovascular samples. These results indicate that S. mutans is a possible causative agent of cardiovascular disease.Accumulated evidence suggests that oral bacterial pathogens are associated with several kinds of systemic diseases, such as infective endocarditis (IE), cardiovascular diseases, bacterial pneumonia, low birth weight, and diabetes mellitus (12). Those associations are speculated to be initiated by transient or prolonged bacteremia caused by oral infection: i.e., from professional dental treatments and daily oral care practices such as tooth brushing and flossing, as well as from food chewing, which possibly induces dissemination of oral bacteria into the bloodstream (21). Oral streptococcal species are major components of the oral microflora that are known to occasionally cause bacteremia and IE (13). Streptococcus mutans, a major pathogenic agent of dental caries, has also been isolated from the blood of patients with IE, strongly suggesting a close relationship of the pathogen with IE (5, 23, 24).The recent development of several molecular techniques has enabled prompt identification of targeted bacterial species in specimens with significantly improved specificity and sensitivity. PCR methods using primers constructed with a species-specific nucleotide alignment are widely used for the detection of specific species. In addition, broad-range eubacterial PCR with amplification of bacterial DNA and subsequent direct sequencing is considered to be a reliable diagnostic tool ...

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

“…The detection of S. mutans in specimens taken from patients with IE has been reported by either conventional or molecular techniques (Gauduchon et al, 2001;Nakano et al, 2006;Nomura et al, 2006;Vose et al, 1987;Ullman et al, 1988). Since IE is initiated by the colonization of the organism on the ECM of damaged endothelium in heart tissue (Moreillon & Que, 2004), bacterial molecules associated with adhesion to ECM are considered important.…”

Interleukin-37 suppresses the osteogenic responses of human aortic valve interstitial cells in vitro and alleviates valve lesions in mice

“…We and others have observed that stimulation of either Toll-like receptor (TLR) 2 or TLR4 induces the osteogenic responses characterized by the expression of BMP-2 and ALP, among several other osteogenic biomarkers, in human AVICs (8)(9)(10)(11)(12), leading to the formation of calcification deposits in vitro (11)(12)(13). Moreover, bacteria associated with chronic periodontal infection and bacterial agents have been detected in diseased human aortic valves (14,15), and inoculation of rabbits with oral bacteria induces aortic valve lesions (16). These findings suggest a link between TLRs and CAVD.…”

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

“…We have been conducting studies to determine the frequency of detection of oral bacteria in cardiovascular specimens (Nakano et al, 2006a and were interested in the clinical distribution frequency of strains similar to V1-V7. Thus the presence of these strains in cardiovascular specimens, including heart valve and atheromatous plaque samples extirpated during surgery, and dental plaque samples obtained during oral examination were analysed using the PCR method constructed for this study.…”

“…A total of 190 cardiovascular specimens (112 from heart valves and 78 from aortic aneurysms), collected from patients who underwent operations at the Department of Cardiovascular Surgery, Osaka Rosai Hospital, Sakai, Osaka, Japan, between December 2004 and July 2007, according to a protocol approved by the Ethics Committee of Osaka Rosai Hospital, and 49 dental plaque specimens collected from patients referred to the Department of Oral Surgery of Osaka Rosai Hospital prior to cardiovascular surgery, were then examined. Bacterial DNA was extracted from each specimen as described previously (Nakano et al, 2006a) and PCR analyses constructed for this study were carried out. The nucleotide alignment of amplified fragments from each positive specimen was confirmed by sequencing analysis.…”