Differences in the composition of the subgingival microbiota of two periodontitis populations of different geographical origin. A comparison between Spain and The Netherlands

The purpose of this study was to compare the subgingival microbiota of two geographically distinct patient populations using identical clinical and bacteriological methods. Adult patients with a diagnosis of periodontitis were consecutively selected according to pre-defined clinical criteria. Microbiological samples were taken from the deepest four sites with bleeding. The samples were plated on blood agar plates, for the determination of the total anaerobic counts and identification of specific bacterial pathogens, and on TSBV and McConkey for isolation of Actinobacillus actinomycetemcomitans and enteric rods, respectively. Thirty-one patients in Spain and 30 patients in The Netherlands were selected. Both patient groups showed similar clinical characteristics, both in terms of age, gender and periodontal clinical variables. A. actinomycetemcomitans was significantly more prevalent (23.3% vs. 3.2%) in the Dutch group, while Porphyromonas gingivalis was significantly more prevalent (64.5% vs. 36.7%) in the Spanish group. Bacteroides forsythus and most commensal periodontal pathogens showed similar prevalences, except Peptostreptococcus micros that was significantly more frequent in the Dutch group (96.7% vs, 74.2%). In summary, the subgingival microbiota from the Spanish group was characterised by a high prevalence of P. gingivalis and low of A, actinomycetemcomitans, while the flora from the Dutch group was characterised by a high prevalence of A. actinomycetemcomitans and P. micros.