Streptococcus suis in Water Buffalo Calves: First Report with Histological and Genomic Insights

In this study, two cases of sudden death following infection-like symptoms in dairy water buffalo calves aged 5 - 12 days were investigated by anatomopathological examinations and laboratory tests. Four bacterial infectious agents were isolated from the brain, which presented meningitis-like lesions, and liver, which appeared hyperaemic and with fibrin formations. The four isolates were phenotypically identified as Streptococcus suis and found to be genetically identical by whole genome sequencing (WGS). One of the isolates was further characterized by hybrid short and long reads genome sequencing and found to represent a novel sequence type (ST) of S. suis serotype 2 . Further investigations are needed to better understand its pathogenic potential, host specificity and environmental sources of infection.