Quantitative detection and virulence gene profiling of Prevotella intermedia and Porphyromonas gingivalis in periodontitis patients

Objective: The present study was designed to determine the prevalence and detection of key virulence genes in individuals with gingivitis and periodontitis in Al-Diwaniyah Governorate and is one of the initial reports of fimA and adpC gene prevalence in Iraq. Methods: Patients' age ranged from 18 to 68 years (mean = 36.77 years). Ninety clinical isolates were collected from these patients. The real-time PCR detected P. gingivalis and P. intermedia to calculate the number of bacterial loads [cycle threshold (Ct) values and copy numbers] and to detect the virulence factors fimA and adpC. Results: The percentages of detection for P. intermedia and P. gingivalis were 82.22% and 34.44%, respectively. The differences were found independent of sex and age. The average age of infected participants was 36.47±8.67 and 39.16±8.31 years for P. intermedia and P. gingivalis, respectively. Cycle threshold values were 33.69±4.45 and 26.85±3.71, and loads were 533,612 and 745.95 copies, respectively. P. gingivalis was more abundant in subjects over 45 years, while P. Intermedia was more frequent in those over 65. The fimA gene was present in 60% of P. gingivalis isolates, and adpC in 70% of P. intermedia. Conclusion: The percentage of P. intermedia was higher than that of P. gingivalis in periodontitis patients. The higher bacterial load with age indicated that cumulative tissue damage is involved. fimA and adpC genes were also particularly informative as they represent potential diagnostic and therapeutic targets. High P. intermedia prevalence suggests its role as a primary pathogen in periodontitis.