[ahayes]

I don't think there's any point in even beginning to discuss this because the person who wrote that article is cherry-picking their data. They say nothing about penicillin resistance, MRSA, and vancomycin resistance. All three of these are antibiotic resistances that are dependent on the origin of novel genes and gene families.

[Getready]

You are incorrect in your statement about MRSA. For staph aureus
most of the resistance mechanisms are due to plasmid transmission
of already existing genes, or tranposons, or mutation of
a gene alreay present. There may be two "novel" chromosomal
areas which have been acquired from an unknown source. Most
of the resistance is therefore due to already existing genes.
At least two are of unknown origin.