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


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.


CONCLUSIONS
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.
Tsuzukibashi
O
O
Department of Laboratory Medicine for Dentistry, Nihon University School of Dentistry at Matsudo, Matsudo, Chiba, Japan.
Takada
K
K
Saito
M
M
Kimura
C
C
Yoshikawa
T
T
Makimura
M
M
Hirasawa
M
M
D016976:Aggregatibacter actinomycetemcomitans / Q000254:growth & development* / Q000302:isolation & purification*; D055113:Chronic Periodontitis / Q000382:microbiology*; D003470:Culture Media / Q000737:chemistry*; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D012703:Serotyping; D013045:Species Specificity
D003470:Culture Media; D004269:DNA, Bacterial