Mecillinam susceptibility of Escherichia coli K-12 mutants deficient in the adenosine 3',5'-monophosphate system.

The mecillinam resistance of Escherichia coli K-12 mutants deficient in the enzyme responsible for the synthesis of adenosine 3',5'-monophosphate, adenylate cyclase, has been investigated. The results suggest that resistance to this antibiotic may be a consequence of the slow growth rate of these mutants rather than an intrinsic property of their genetic lesion.