SHMT2 and periodontitis: Patients in group III (n = 15) with aggressive periodontitis showed the maximum isolates (n = 7; 46.6%) followed by group II with one isolate (6.66%) of T. forsythia (Table 1). The frequency of the glyA gene was more in group III (57.14%) when compared to the other groups. Compared to younger patients, elder patients had a higher frequency of isolates.