Escherichia coli K1's Capsule Is a Barrier to Bacteriophage T7

Infection of EV36 by T7 is blocked by capsule. A lawn of EV36 was spotted with 0.3 mg/ml of endosialidase, which had little effect on growth (a); 0.3 mg/ml of endosialidase plus 10⁴ T7 particles (growth is indicated by clearing); T7 alone, which could not adsorb (c); and 10⁴ phage K1-5 particles (K1 specific) (d).