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 ba cteriological methods. Adult patients with a diagnosis of periodontitis wer e consecutively selected according to pre-defined clinical criteria. Microb iological samples were taken from the deepest four sites with bleeding. The samples were plated on blood agar plates, for the determination of the tot al 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 patien ts in The Netherlands were selected. Both patient groups showed similar cli nical characteristics, both in terms of age, gender and periodontal clinica l variables. A. actinomycetemcomitans was significantly more prevalent (23. 3% vs. 3.2%) in the Dutch group, while Porphyromonas gingivalis was signifi cantly more prevalent (64.5% vs. 36.7%) in the Spanish group. Bacteroides f orsythus and most commensal periodontal pathogens showed similar prevalence s, 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. gingiva lis and low of A, actinomycetemcomitans, while the flora from the Dutch gro up was characterised by a high prevalence of A. actinomycetemcomitans and P . micros.