Hydrolyzes cAMP to 5'-AMP. Plays an important regulatory role in modulating the intracellular concentration of cAMP, thereby influencing cAMP-dependent processes. Specifically required for regulation of virulence factors. Can also hydrolyze cGMP, but cGMP is unlikely to be synthesized by P.aeruginosa and cAMP is probably the biologically relevant substrate for CpdA in vivo. 3',5'-cyclic AMP + H2O = AMP + H(+) Binds 2 metal cations per subunit. Site 1 may preferentially bind Fe(3+) ions, while site 2 may have a preference for Fe(2+) ions. Activated by iron. Other divalent metal ions have no effect. Monomer. Positively regulated by Vfr in response to elevated intracellular cAMP. Mutants show increased levels of cellular cAMP. In rich medium, mutants exhibit a significantly reduced growth rate compared to wild-type strain. Belongs to the cyclic nucleotide phosphodiesterase class-III family.