PLD1 and pneumonia: Furthermore, in a hypervirulent strain Kp52.145, another T6SS effector gene pld1, encoding a phospholipase D family protein (PLD1), located within the T6SS locus, was reported as a virulence factor, exhibiting that Δpld1 was avirulent in comparison to wild-type in a mouse model of pneumonia (Lery et al., 2014).