First sporadic case of pathogenic Escherichia coli infection in Black swan in China

• Isolated a strain (B-1) from a diseased black swan died from enteritis diarrhea.
• Phylogenetic analysis indicated that B-1 strain is identical to Escherichia coli.
• Animal regression test were the same as the disease physio infected.
• B-1 strain was highly susceptible to antibiotic of streptomycin.
• First sporadic case of pathogenic E. coli infection in Black swan in China.

A strain of bacteria was isolated from the diseased black swan (Cygnus atratus) died from enteritis diarrhea, and designated tentatively as B-1 strain. Morphological and biochemical tests, as well as phylogenetic analysis derived from 16S rRNA and fimC gene sequencing both strongly indicated that B-1 strain is identical to Escherichia coli. Furthermore, the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) profile of the isolate was different from that of two reference strains. Antibiotic sensitivity testing of B-1 strain was carried out by the standard Kirby-Bauer disc diffusion method. Animal experiments demonstrated that B-1 strain is pathogenic to mice and chickens. This is first sporadic case of pathogenic E. coli infection in Black swan in China.