While many groups of bacteria associated with Periodontal Disease were present in low amounts, one was elevated: Brevundimonas, a group which has been associated with more refractory cases of Periodontal Disease in humans In addition, two groups of bacteria considered pathobionts were elevated: Acinetobacter and Proteus, both of which are problematic groups. Overabundance of Brevundimonas One of several species of microorganisms which have been identified as having a natural melanogenic capacity (complex process by which the pigment melanin is produced in melanosomes by melanocytes). Is an overabundance of Brevundimonas a biomarker for Melanoma?