Genetic diversity and virulence gene profiles of Escherichia coli from diarrhoeal rabbits in Sichuan Province, China

Abstract

Escherichia coli (E. coli) can cause diarrhoea in a wide range of hosts. Moreover, some trains with high virulence and drug resistance pose a serious threat to public health and livestock products. Diarrhoea caused by E. coli outbreaks in rabbitries result in serious economic losses. The aim of this study was to investigate the distribution of virulence genes and molecular genetic characteristics of E. coli from diarrhoeal rabbits in the main rearing areas of Sichuan province, China in 2015-2017. In total, 39 E. coli isolates were identified and undivided divided into 17 sequence types by multilocus sequence typing (MLST) and grouped in 22 clusters by pulsed-field gel electrophoresis. Polymerase chain reaction tests detected 6 virulence genes: eae (41.0%), ler (41.0%), ral (33.3%), afr2 (10.3%), irp2 (15.4%) and astA (7.7%) of the tested 17 virulence genes identifying 16 enteropathogenic E. coli (EPEC) isolates. The main sequence types U328, ST328 and ST20 carried rabbit EPEC associated virulence genes (eae, ler, ral and afr2). The results showed that the distribution of virulence genes varied by year and area; genotype had major types in local rearing areas but was of high diversity in Sichuan province.