Coincidence of Sulfate-reducing bacteria (SRB) with P.gingivalis

Introduction: SRB partake in a variety of anaerobic microbial ecosystems as terminal degraders of the fermentation end-products. In recent years, the occurrence of SRB in periodontitis patients has been reported by our research group. The aim of this study was to monitor the prevalence of SRB in periodontal diseases, and to find out the coincidence of SRB with other putative periodontal pathogenic bacteria. Material and methods: The presence of SRB was determined by real time PCR of Desulfomicrobium orale and Desulfovibrium fairfieldensis using the GeneAmp 5700 Sequence Detection System. TaqMan probe was used for fluorescence revelation. We used the ParoCheck® Kit 20 assay determining 20 periodontopathogens. Each periodontal pathogen is detected by five measuring points on the chip. The analysis of bound probes is then carried out using the CheckReport analysis-software. Fifteen patients in the recall program who had completed conventional periodontal therapy with remaining probing pocket depths of 5-8 mm were enrolled. The clinical parameters, which included PD, AL, BoP, GI and PI were recorded and microbiological samples and GCF samples were collected at base-line, 3 and 6 months. The study was performed according to the guidelines of the ethical commission of the University of Witten/Herdecke. Statistical comparison was performed by Mann-Whitney U test and at different time intervals by Kruskal-Wallis coupled with Wilcoxon signed-rank test. An alpha level of < 0.05 was considered statistically significant. Results: Presence of SRB was negatively correlated with Aa presence in periodontal pockets (p<0.05). SRB were found to be associated with occurence of Pg, Tf and Td at least in one pocket. Conclusions: Our clinical study indicates the SRB as “late colonizers” in the subgingival biofilm formation. Therefore, the presence of SRB may indicate pockets in a state of risk for progressive destructive periodontal disease.