High and selective resistance to mecillinam in adenylate cyclase-deficient or cyclic adenosine 3',5'-monophosphate receptor protein-deficient mutants of Escherichia coli.

AUTOR(ES)

Aono, R

RESUMO

Adenylate cyclase-deficient (cya) mutants of Escherichia coli K-12 were selectively and highly resistant to mecillinam (FL1060) among several beta-lactam antibiotics in the absence of cyclic adenosine 3',5'-monophosphate (cAMP). They became sensitive to the drug in the presence of cAMP. Also, cAMP receptor protein-negative (crp) mutants, with the exception of strain 5333, were highly resistant to mecillinam in the presence and in the absence of cAMP. Mecillinam exerted two distinct and sequential effects in both cya+ strains and cya strains supplemented with cAMP: (i) rounding of cells and (ii) cessation of cell division. The first effect was accompanied by a decrease in growth rate, whereas the second effect was accompanied by enlargement and lysis of the rounded cells. The second effect of mecillinam was dependent on inoculum size and cAMP. When the cell density was above about 10(6) cells per ml, the rounded cells stopped dividing but did not lyse. In the absence of cAMP, cya strains neither stopped dividing nor lysed; they were resistant to the second, lethal effect of mecillinam.

Documentos Relacionados

• Properties of adenyl cyclase and cyclic adenosine 3',5'-monophosphate receptor protein-deficient mutants of Escherichia coli.
• Changes in composition of envelope proteins in adenylate cyclase- or cyclic AMP receptor protein-deficient mutants of Escherichia coli.
• Cyclic adenosine 3',5'-monophosphate levels and activities of adenylate cyclase and cyclic adenosine 3',5'-monophosphate phosphodiesterase in Pseudomonas and Bacteroides.
• Mecillinam Susceptibility of Escherichia coli K-12 Mutants Deficient in the Adenosine 3′,5′-Monophosphate System
• Cyclic Adenosine 3′,5′-Monophosphate in Escherichia coli