Inhibitors of bacterial c-di-GMP or c-di-AMP phosphodiesterases have the potential to be used as anti-virulence compounds, while compounds that inhibit the degradation of 3′,3′-cGAMP, cA3, cA4, cA6 could serve as antibiotic adjuvants as the accumulation of these second messengers leads to bacterial abortive infection. Here, CA4 is linked to infection.