col·i·cin 
(kŏlĭ-sĭn, kōlĭ-)
(kŏlĭ-sĭn, kōlĭ-)n.
Any of various antibacterial proteins produced by certain strains of E. coli that inhibit or kill closely related species or strains of bacteria.
[New Latin colī, specific epithet of Escherichia colī; see E. COLI + -(I)C + -IN.]