A free-ranging subadult, male green turtle (Chelonia mydas) presented with radiographic evidence of pneumonia and died acutely. On necropsy, the trachea and bronchi were plugged by diphtheritic membranes, comprised of fibrin, necrotic debris, and colonies of bacilli, identified as Serratia proteamaculans. S. proteamaculans, typically considered an opportunistic plant pathogen, has rarely been described as causing disease in animals. This is the first report of S. proteamaculans causing severe necrotizing tracheitis and bronchopneumonia in a reptile.
