Serratia marcescens infection in a swallow-tailed hummingbird

A swallow-tailed hummingbird (Eupetomena macroura) was presented with a history of prostration and inability to fly. After a 2-day hospitilization, the bird died and necrospy findings included diffuse hyperemia of the small intestine serosal and nucosal surfaces and the presence of a small quantity of clear ascitic fluid in the coelomic cavity. Intestinal contents and cardiac blood were collected for microbiological exams yielding pure cultures of a pigmented strain of Serratia marcescens. This strain was susceptible to gentamicin, enrofloxacin, streptomycin, trimethoprim, and sulfamethoxale and had intermediate susceptibility to chloramphenicol and resistance to cephalotin. The source of the infection could not be ascertained, but possible contamination of hummingbird feeders could be involved, because the infection seemed to originate from the digestive tract.