As far as definitions are concerned, some use “microbiome” to mean all the microbes in a community.

We and others use it to mean the full collection of genes of all the microbes in a community. The human microbiome (all of our microbes’ genes) can be considered a counterpart to the human genome (all of our genes). The genes in our microbiome outnumber the genes in our genome by about 100 to 1.