ANTIBIOTIC RESISTANCE - (Oct/15/2007 )

What is the cause of antibiotic resistance in pathogenic organisms. Is it a gene present on a plasmid or is it just mutation of a certain gene that makes it produce antibiotic degrading enzymes?

I would also be interested in the cause of resistance to antibiotic in Salmonella.

MG

Either.

Promiscuous plasmds or phage can cross species or strain barriers and carry resistance. These can also carry transposons which insert into the chromosome (this is perhaps even more common).

Mutations can convey resistance to certain antibiotics, often the ones targeting ribosomal function.

There is a very large literature on this subject describing resistance to virtually every antibiotic you've heard of, and many you have not.