Actinobacillus actinomycetemcomitans serotype e - biotypes, genetic diversity and distribution in relation to periodontal status

Actinobacillus actinomycetemcomitans isolates from 356 individuals were scr eened for identification of serotype e in order to investigate its distribu tion in relation to periodontal status. From subjects with serotype e, 1-6 isolates per subject (n= 61) were genotyped using arbitrarily primed-polyme rase chain reaction (AP-PCR) and apaH gene polymerase chain reaction-restri ction fragment-length polymorphism (PCR-RFLP) analysis to determine the gen etic heterogeneity within the serotype. Furthermore, one serotype e strain per subject was tested for fermentation of 8 carbohydrates for biotyping. A mong patients with adult periodontitis (n=219), localized juvenile periodon titis (n=55) and other forms of early-onset periodontitis (n=18) serotypes b, a and c, respectively, were the most frequently detected serotypes. Non- periodontitis subjects (n=64) were predominantly colonized with serotype c. Serotype e was found in 30 (14%) adult periodontitis patients, 2(11%)early -onset periodontitis patients and in 5 (8%) non-periodontitis individuals, but in none of the 55 localized juvenile periodontitis patients. AP-PCR dis tinguished 3 and apaH gene PCR-RFLP analysis 2 genotypes among the 61 A. ac tinomycetemcomitans serotype e isolates, one genotype per subject. The AP-P CR genotypes and 3 represented the apaH genotype and the AP-PCR genotype 2 the apaH genotype 2. On the basis of variable fermentation of galactose and xylose, 3 biotypes among A. actinomycetemcomitans serotype e were establis hed. Contrary to the absence of A. actinomycetemcomitans serotype e in loca lized juvenile periodontitis patients, its detection frequency was comparab le among other forms of periodontitis and periodontal health. Clinical sero type e isolates form at least ? genetic types and 3 biotypes.