Direct detection of Streptococcus mutans in human dental plaque by polymerase chain reaction

Abstract

Streptococcus mutans is an etiological agent in human dental caries. A method for the detection of S. mutans directly from human dental plaque by polymerase chain reaction has been developed. Oligonucleotide primers specific for a portion of the dextranase gene (dexA) of S. mutans Ingbritt (serotype c) were designed to amplify a 1272-bp DNA fragment by polymerase chain reaction. The present method specifically detected S. mutans (serotypes c, e and f), but none of the other mutans streptococci: S. cricetus (serotype a), S. rattus (serotype b), S. sobrinus (serotypes d and g), and S. downei (serotype h), other gram-positive bacteria (16 strains of 12 species of cocci and 18 strains of 12 species of bacilli) nor gram-negative bacteria (1 strain of 1 species of cocci and 20 strains of 18 species of bacilli). The method was capable of detecting 1 pg of the chromosomal DNA purified from S. mutans Ingbritt and as few as 12 colony-forming units of S. mutans cells. The S. mutans cells in human dental plaque were also directly detected. Seventy clinical isolates of S. mutans isolated from the dental plaque of 8 patients were all positive by the polymerase chain reaction. These results suggest that the dexA polymerase chain reaction is suitable for the specific detection and identification of S. mutans.

Longitudinal study of dental caries incidence associated with Streptococcus mutans and Streptococcus sobrinus in pre-school children

“…This tool provides a more sensitive means of detection of cariogenic bacterial species, as compared to conventional culture techniques (Ono et al, 1994;Igarashi et al, 1996Igarashi et al, , 2000.…”

“…S. mutans JCM5175 T and S. sobrinus ATCC27607 T were used as controls. PCR detection of the tested species was performed using primers described by Igarashi et al (1996Igarashi et al ( , 2000 while that of 16S rDNA was done by the method of Goncharoff et al (1993).…”

“…Several investigators have also developed PCR methods and reported them to be more sensitive for detection than conventional culture techniques (Ono et al, 1994;Igarashi et al, 2000), as they have been shown to be able to detect low numbers of bacterial species with a detection limit of as few as 25-100 cells (Igarashi et al, 1996(Igarashi et al, , 2000, while being quick and relatively simple to perform. Further, PCR assays were found to be suitable for the specific detection and identification of human cariogenic bacteria, such as S. mutans and S. sobrinus (Igarashi et al, 1996(Igarashi et al, , 2000Shiroza et al, 1998).In a previous cross-sectional study, we reported that children harbouring both S. mutans and S. sobrinus had a significantly higher incidence of dental caries than those with S. (Okada et al, 2002). However, there are few longitudinal studies of the relationship between these two species and caries activities in children (Hirose et al, 1993).…”

“…S. mutans JCM5175 T and S. sobrinus ATCC27607 T were used as controls. PCR detection of the tested species was performed using primers described by Igarashi et al (1996Igarashi et al ( , 2000 while that of 16S rDNA was done by the method of Goncharoff et al (1993).Plaque samples were first harvested by centrifugation at 1600 g for 20 min. The supernatants were then discarded, and individual cell pellets were stored at À20 8C until DNA isolation.…”

Prevalence of cariogenic streptococci on incisor brackets detected by polymerase chain reaction

“…PCR is a simple, rapid, and highly specific method that uses specific DNA fractions for the detection and identification of microorganisms. 13,14 The purpose of this study was to analyze the prevalence of cariogenic streptococci on incisor brackets in vivo and to evaluate the relationship between cariogenic streptococci and oral hygiene indexes in maxillary incisor regions with the specific PCR methods for S sobrinus and S mutans.…”