Korfmann G, Kliebe C, Wiedemann B
J Antimicrob Chemother. 1986 Oct;18 Suppl C:113-21. doi: 10.1093/jac/18.supplement_c.113.
In this paper we describe two genetic mechanisms which are responsible for the development of resistance to third-generation cephalosporins. One is a plasmid-mediated mechanism involving a mutation in the SHV-1-gene towards the production of the beta-lactamase SHV-2 which has increased affinity for these antibiotics. The other is chromosomally mediated and occurs at high frequency by mutation of inducible beta-lactamase-genes, leading to derepressed production of the enzyme. Together with other examples of resistance genes these two mechanisms lead us to a hypothesis about the evolution of beta-lactamase producing bacteria.
