Structural investigation of a polysaccharide from the mycelium of Enterobacter cloacae and its antibacterial activity against extensively drug-resistant E. cloacae producing SHV-12 extended-spectrum β-lactamase.

•A novel neutral homopolysaccharide (ECP) is isolated from Enterobacter cloacae.•The structure of ECP can be determined as {→6)- β-Glcp-(1 → 4)-β-Glcp-(1 → }n.•ECP exhibites strong antibacterial activities against SHV-12 ESBL E. cloacae.•Antibacterial activities of ECP are achieved by cell membrane damage.