Table 3. Frequencies of Y. pestis spontaneous mutations to bacteriophage resistance.

Y. pestis strain	Mutation frequency of resistance to:
	L-413C	ϕA1122	Pokrovskaya	Y
CO92 Pgm−	1.2×10−4	<3.1×10−10	5.5×10−6	5.3×10−7
KIM D27	1.1×10−4	<4.2×10−10	NTa	NT
A1122	1.0×10−4	NT	NT	NT

^aNT, not tested.