Table 2.

Effect of phage mutations on phage and SaPI titres. (The means of results from three independent experiments are shown. Variation was within ±5% in all cases.)

donor strain
phage	SaPI	phage titrea	SaPI titreb
ϕ SLTpvl::tetM	—	5.0 × 106
ϕ SLTpvl::tetM ΔORF42	—	<10	—
ϕ SLTpvl::tetM	SaPIbov5adjusted	1.74 × 106	1.72 × 106
ϕ SLTpvl::tetM ΔORF42	SaPIbov5adjusted	<10	<10

^aPFU ml⁻¹ induced culture, using RN4220 as recipient strain.

^bNumber of transductants ml⁻¹ induced culture, using RN4220 as recipient strain.