[gore3000]

By that train, viruses are not alive.

Correct, they are not alive, they cannot reproduce for one thing. A living organism requires many things, one of the essentials is energy.

Mycoplasma pneumoniae is one of the smallest bacteria known with a cell diameter of about 0.5 mm and a genome size of 816 kbp coding for 687 genes. The annotation of the complete genome sequence made it possible to predict functions for 68% of the genes. This information is sufficient to understand metabolic pathways and the synthesis of macromolecules, but more knowledge is required for understanding the three key processes characterizing all living systems that are metabolism, defined as the sum of all chemical reactions taking place in the cell, reproduction and adaptation.
From: Richard Hrennmann's Home Page.

[BiffWondercat]

The next (search engine) result gives the TIGR map.
Shall I cut and paste it as well?

[Junior]

Mycoplasma pneumoniae is one of the smallest bacteria known with a cell diameter of about 0.5 mm [sic] and a genome size of 816 kbp coding for 687 genes.

As 0.5 mm is absolutely huge when it comes to bacteria, one can pretty much dismiss this "expert's" claims.

[Timesink]

Mycoplasma pneumoniae is one of the smallest bacteria known with a cell diameter of about 0.5 mm

Half a millimeter? That would make it visible to the human eye.