Copyright © 2006, American Society for Microbiology. All Rights Reserved.
Detection of Cariogenic Streptococcus mutans in Extirpated Heart Valve and Atheromatous Plaque Specimens
Kazuhiko Nakano,1 Hiroaki Inaba,2 Ryota Nomura,1 Hirotoshi Nemoto,1 Munehiro Takeda,3 Hideo Yoshioka,3 Hajime Matsue,4 Toshiki Takahashi,4 Kazuhiro Taniguchi,4 Atsuo Amano,2 and Takashi Ooshima1*
Departments of Pediatric Dentistry,1 Oral Frontier Biology, Osaka University Graduate School of Dentistry, 1-8 Yamada-oka, Suita, Osaka 565-0871, Japan,2 Dentistry and Oral Surgery,3 Cardiovascular Surgery, Osaka Rosai Hospital, 1179-3 Nagasane-cho, Sakai, Osaka 591-0825, Japan4
Received 20 February 2006/ Returned for modification 19 April 2006/ Accepted 15 July 2006
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.