IADR Abstract Archives
Characterization of Genetic Diversity in Porphyromonas Gingivalis: MALDI-TOF-MS, MLST, PFGE
Objectives: P. gingivalis, is highly prevalent in Colombian periodontitis patients (71.5%), and shows variability in the virulence, suggesting multiple clonal types associated with periodontal health or disease. To understand its virulence and evolution, exploring its genetic diversity and patterns of genetic exchange is necessary. Objective: To evaluate and compare the genetic diversity of Colombian clinical isolates of P. gingivalis using MALDI-TOF-MS, MLST, and PFGE.
Methods: 39 P. gingivalis isolates from subgingival plaque (n=34) and peripheral blood (n=5) from diagnosed periodontitis patients were evaluated. Each isolate was cultured on Brucella agar supplemented with hemin/menadione and sheep blood and incubated at 37°C for 7 days under anaerobic conditions. They were typed using mass spectrometry (MALDI-TOF-MS), multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Reference strains P. gingivalis ATCC33277 and W83 were used as controls. Simpson's Diversity Index (SID) was evaluated, and concordance between methods was determined using adjusted Rand Index (AR) and adjusted Wallace Coefficient (AW) with 95% confidence intervals.
Results: All isolates exhibited new sequence types (ST), not previously reported in the worldwide, showing high heterogeneity and differences with reference strains. Simpson's diversity indices were 0.994, 0.983, and 0.979 for PFGE, MALDI-TOF-MS, and MLST, respectively. Results revealed 11.2% concordance between MALDI-TOF-MS and MLST, 35.8% between MLST and PFGE, and 20.3% between MALDI-TOF-MS and PFGE. MALDI-TOF ↔ MLST and MALDI-TOF ↔ PFGE comparisons showed statistical differences p=0.024
Conclusions: P. gingivalis isolates exhibit marked genetic diversity. Although MALDI-TOF-MS is valuable for revealing variability, significant differences exist when compared to other typing methods.
Methods: 39 P. gingivalis isolates from subgingival plaque (n=34) and peripheral blood (n=5) from diagnosed periodontitis patients were evaluated. Each isolate was cultured on Brucella agar supplemented with hemin/menadione and sheep blood and incubated at 37°C for 7 days under anaerobic conditions. They were typed using mass spectrometry (MALDI-TOF-MS), multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Reference strains P. gingivalis ATCC33277 and W83 were used as controls. Simpson's Diversity Index (SID) was evaluated, and concordance between methods was determined using adjusted Rand Index (AR) and adjusted Wallace Coefficient (AW) with 95% confidence intervals.
Results: All isolates exhibited new sequence types (ST), not previously reported in the worldwide, showing high heterogeneity and differences with reference strains. Simpson's diversity indices were 0.994, 0.983, and 0.979 for PFGE, MALDI-TOF-MS, and MLST, respectively. Results revealed 11.2% concordance between MALDI-TOF-MS and MLST, 35.8% between MLST and PFGE, and 20.3% between MALDI-TOF-MS and PFGE. MALDI-TOF ↔ MLST and MALDI-TOF ↔ PFGE comparisons showed statistical differences p=0.024
Conclusions: P. gingivalis isolates exhibit marked genetic diversity. Although MALDI-TOF-MS is valuable for revealing variability, significant differences exist when compared to other typing methods.