Recent reports suggested that PDE5 restricts accumulation of intracellular cGMP during ST-ETEC infection (11), but our RNA-seq data show that cGMP-specific PDE9 is upregulated (1.66-fold; q = 1.38e−05), while PDE5 is downregulated (2.1-fold; q = 3.24e−02) in T84 cells following 3 h ST intoxication (see the supplemental material), suggesting that the response to acute changes in cGMP concentrations is more complex than previously described. The gene discussed is PDE5A; the disease is infection.