Pyocyanin production by bacteria
In poultry and pigs it is frequent to find, during necropsies, greenish-blueish lesions. For example, green yolks in infectious toxic hepatoenteritis, green patchy superficial lesions on the Glisson’s capsule or green pericardium in avian septicemia, as well as purulent material in porcine retropharyngeal abscesses.
In all cases, the colour is a consequence of the green or blue pigment called pyocyanin, produced by bacteria such as Pseudomonas aeruginosa.
This picture depicts isolated Pseudomonas that spread pyocyanin in pathological material.