Streptococcus mutans, Streptococcus sobrinus and Candida albicans in oral samples from caries-free and caries-active children.

AIM: This was to examine the occurrence of S. mutans, S. sobrinus and C. albicans in dental plaque and saliva from caries-free and caries-active Greek children. METHODS: Saliva and dental plaque samples from 46 caries-free and 51 caries-active 3-to-13-year-old children were examined using selective media for the three microbes. Identification of isolated mutans streptococci (S. mutans and S. sobrinus) was performed with biochemical test and specific DNA probes. The salivary levels of mutans streptococci were additionally determined by a chair-side test (Dentocult® SM strips). RESULTS: The isolation frequencies of S. mutans, S. sobrinus and C. albicans were 66, 11 and 18 %, respectively. Caries-active children harboured more frequently and at significantly higher numbers the specific microbes than caries-free children. A similar pattern was observed with the Dentocult® SM strip scores. No correlation was found between the presence of these microbes and the age or gender of the children. CONCLUSIONS: Caries experience was statistically significantly related to the presence of all three microbes under study, both in dental plaque and saliva.

Characterization of a new serotype g isolate of Aggregatibacter actinomycetemcomitans.

Aggregatibacter actinomycetemcomitans is usually isolated from the oral cavity where it is associated with active periodontitis. The species can be divided into six serotypes (a-f) according to their surface carbohydrate antigens. However, some clinical isolates cannot be grouped within these six serotypes. Gram-negative, facultative anaerobic, catalase-positive coccobacilli were isolated from a patient with periodontitis and identified by employing genetic, biochemical and serological analyses. Phenotypic data identified the isolate as A. actinomycetemcomitans. Serotype-specific polysaccharide antigen from the isolate was untypeable by immunodiffusion testing in comparison with reference A. actinomycetemcomitans serotype a to f strains. Biofilm formation by the isolate was strong but cytotoxic activity was low. Gas chromatography/mass spectroscopy analysis of partially methylated alditol acetates from surface polysaccharide showed the presence of 2,4-di-O-methyl-rhamnose and 2,3,6-tri-O-methyl-glucose, with a 1 : 1 m ratio. The (1)H- and (13)C-nuclear magnetic resonance spectra of the antigen showed that both constituent glycoses had alpha-anomeric configuration. It is proposed that the untyped strain is a new A. actinomycetemcomitans serotype, designated serotype g.

A novel selective medium for isolation of Aggregatibacter (Actinobacillus) actinomycetemcomitans.

BACKGROUND AND OBJECTIVE: Conventional selective media have been used for the selection of Aggregatibacter (Actinobacillus) actinomycetemcomitans in clinical samples. The proportion of A. actinomycetemcomitans grown on the selective media in vitro may not reflect the true counts in vivo because of the low selectivity. A novel selective medium, designated AASM, was developed for the isolation of A. actinomycetemcomitans. MATERIAL AND METHODS: AASM was prepared by adding of 200 microg/mL of vancomycin and 10 U/mL of bacitracin to AAGM, which contains dextrose, sodium bicarbonate, trypticase soy, yeast extract and agar. Clinical efficacy was evaluated by the recovery, on AASM, of A. actinomycetemcomitans from subgingival samples of 44 periodontally healthy subjects and 76 patients with chronic periodontitis. RESULTS: All serotypes (a-f) of A. actinomycetemcomitans strains grew well, and the average growth recovery of A. actinomycetemcomitans on AASM medium was 94.4% (80.0-109.7%) of that on AAGM. The exclusive rate of other bacteria was 99.9% in clinical samples cultured on AASM. A. actinomycetemcomitans was not detected in periodontally healthy persons but was detected in 25 (32.9%) patients with chronic periodontitis. The predominant serotype was c, detected in 11 subjects. CONCLUSION: The new selective medium, AASM, was highly selective for A. actinomycetemcomitans, eliminated possible false-positive results and was useful for the isolation of A. actinomycetemcomitans from clinical samples.

Design of a unique PCR primer for detection of oral HPV infection.

Human papillomavirus (HPV) has been known as a pathogen of oral dysplasia. However, suitable PCR primers for the detection of oral HPV infection have not been reported. The aim of this study was to design unique consensus primers. The consensus primers were designed by homologues analyses between subtypes 2, 6, 11, 13, 16, 18, 30, 32 and 58, which frequently infect the oral membrane. PCR, with our designed primer, detected HPV DNA subtypes 2, 6, 11, 16, 18 and 58, and also showed PCR product from a clinical papilloma sample. These results indicate that our designed consensus primer can be used for the study of the relationships between oral disease and HPV infection.