Calcium ions and vitamin B₁₂ are growth factors for Porphyromonas gingivalis

Porphyromonas gingivalis is a causative agent of chronic periodontitis. Standard strains of P. gingivalis, such as W83 and ATCC 33277, proliferate in minimal medium when protein is added as the energy source and hemin and menadione are added as growth factors. Nevertheless, minimal medium containing bovine serum albumin sometimes fails to support growth.

The proliferation of two W83 strains and seven ATCC 33277 strains in various minimal media was investigated. Previously, we determined that calcium chloride (CaCl₂) was a growth factor for W83NM, a W83 strain. In this study, we found that vitamin B₁₂ enhanced the proliferation of W83NM in a minimal medium with cultures from the fourth passage but not from the first to the third passage. Therefore, using fourth-passage cultures, we assessed the proliferation of two W83 and seven ATCC 33277 strains in minimal media and the effects of CaCl₂ and vitamin B₁₂. Surprisingly, the nine P. gingivalis strains all differed with respect to their proliferation in minimal media, and protein products used as energy sources showed product-to-product and lot-to-lot heterogeneity. Even though strains or protein products were different, we found CaCl₂-dependent growth in nine strains and vitamin B₁₂-dependent growth in seven strains.

These results suggest that calcium ions and vitamin B₁₂ are novel growth factors for P. gingivalis.