Differential expression of virulence and potential virulence genes of avian pathogenic Escherichia coli in vitro with DNA microarray analysis

Abstract:

We constructed avian pathogenic Escherichia coli (APEC) specific DNA microarray to analyze the transcriptomes of APEC highly pathogenic strain E058 and low pathogenic strain E526 (both belonging to O2 serotype). For cultures in Luria-Bertani (LB) broth medium, 16 distinctly expressed genes were observed in strain E526, and all of them were down-regulated. For cultures in the serum of chickens, 15 distinctly expressed genes were screened in strain E526, and all of them were also down-regulated. The results suggest that DNA microarray could be used to screen distinctly expressed genes among virulence- and potential virulence-associated genes of APEC. The expression of 11 common virulence- or potential virulence-associated genes were down-regulated for strain E526 compared to those of strain E058 cultured both in LB broth and chicken serum. Meanwhile, 4 potential virulence-associated genes,aes-3,aes-10,aes-13 and aes-15 were down-regulated for strain E526 but not for strain E058, when they grew in the chicken serum. Besides known virulence factors, we observed 10 new potential virulence-related genes including aes-1，aes-2，aes-3, aes-4, aes-6, aes-8, aes-10, aes-13, aes-15 and aes-31.