Cm0957

P. gingivalis strains ATCC 33277 and W83 (kindly provided by ACTA, Amsterdam, The Netherlands) were cultured on blood agar plates under anaerobic conditions at 37°C. At day 7, colonies were transferred to anaerobe basal broth (CM0957, ThermoFisher, Waltham, USA) and cultured for 24h until they reached mid-log growth. Gram staining confirmed purity of the cultures. The bacterial cultures (OD₆₉₀ 0.1) were heat-inactivated at 60°C for 60min.

Fecal samples from CRC patients with high relative abundance of P. micra were used for bacterial isolation. Samples were spread on horse blood agar plates and incubated in anaerobic chamber. The identity of the candidate colony (P. micra strain 512) was determined by gram staining and amplification of 16 S rRNA gene using universal primers targeting hypervariable regions V1-V4 and V6 of the 16 S rRNA gene, with further confirmation by P. micra-specific primers and Sanger sequencing. The bacteria were cultured in anaerobe basal broth (CM0957; Thermo Fisher Scientific) in anaerobic jar (Hardy Diagnostics, Santa Maria, CA). The anaerobic condition was created by the application of Anaerogen (AN0035; Thermo Fisher Scientific). Another strain (P. micra Smith) was bought from American Type Culture Collection (33270,ATCC, Manassas, VA).