Chromobacterium haemolyticum is a fatal gram-negative bacterium, which had been found that has the ability to infect human. In this study, we detected a nonpigmented, β-hemolytic gram-negative bacillus from fecal samples of piglets with severe diarrhea and death. Analysis of the 16S rRNA gene sequence indicated it was most closely related to Chromobacterium haemolyticum, however only with 79% identities, indicating that this bacterium may be a new type of Chromobacterium haemolyticum. Diarrhea was reproduced in experimental pigs with one of the isolates strains, designated GDHYZ30 strain. Intramuscular injection of the GDHYZ30 strain can cause death of the piglets, and irrigated challenge induced piglets diarrhea. To further elucidate the mechanism of pathogensis of this bacterium, whole genome sequencing was used to analyze and annotate the GDHYZ30 strain. The full-length genome of the strain was 4785117bp, the G+C content was 62.67%, and it encoded 4398 genes, in which 57 drug resistance genes, and 390 virulence factors were included. It is worth noting that this novel Chromobacterium haemolyticum has been isolated from several other pig farm water samples and pig feces samples with unexplained diarrhea. To our knowledge this is the first report that a novel Chromobacterium haemolyticum as a new pathogen causing diarrhea and death in piglets and transmiting through water sources. And the genetic characteristics of the bacteria are analyzed by whole gene sequencing, which provides a reference for the prevention of human and animal infections and food safety.

The diarrhoea of pigs, in particular, for the newborns, is very harmful to the pig industry. Porcine circovirus-like virus (Po-Circo-like (PCL) virus) is a circular replication-associated protein (Rep)-encoding single-stranded (CRESS) DNA virus. Two PCL virus strains, with severe diarrhoea and hemorrhagic enteritis, have been found in two different pig farms in Guangdong province, China. Subsequently, the full genomes of two strains (PCL virus GD06 and PCL virus GD09) were sequenced. The two PCL viruses contains 3942 nucleotides and 3925 nucleotides, which vary from the genomes of other PCL virus strains with 3912, 3923, and 3942 nucleotides. Besides, the nucleotide identities between two strains and other strains of PCL viruses and Bo-Circo-like virus/CH were 78%-89%. A multiple sequence alignment of these strains showed a similarity of 86.2%-94.4% for the Rep gene sequence and 89.4%-97.7% for the Rep protein sequence. This study found that 9.5% (4/42) of diarrhoea samples and 11.8% (2/17) of pig farms were positive for PCL virus, suggesting that PCL virus may already be widespread in Pig farms in China. Further research on the pathogenicity and epidemiology of PCL virus is required.