title: 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.
authors.affiliation: Department of Oral Microbiology, Showa University School of Dentistry, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Igarashi
authors.forename: A
authors.initials: A
authors.lastname: Yamamoto
authors.forename: N
authors.initials: N
authors.lastname: Goto
mesh_terms: D000818:Animals; D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis; D003773:Dental Plaque / Q000382:microbiology*; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D051381:Rats; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013291:Streptococcus / Q000302:isolation & purification; D013295:Streptococcus mutans / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial