Co-inoculation of Escherichia coli B23 by T4 and T7 Bacteriophages Results in Competition Shown by an Overall Drop in Phage Progeny

Co-inoculation and co-infection are phenomena that occur naturally in the environment that have implications on. In order to explore competition between T4 and T7 phages, one-step assays were carried out on T4 and T7 monoinfected samples, and a sample co-inoculated by both T4 and T7. Mono-infections were performed at an MOI of 5 in order to ensure infection, and the co-inoculation had an MOI of 5 for both T4 and T7 resulting in a total MOI of 10. It was found that at 90 min post co-inoculation, the overall titer of both phages decreased with respect to their mono-infected controls, 97% for T4 and 98% for T7. This suggested that actual co-infection could have occurred and competition was carried out within the host cell. This effect demonstrated that even though there seems to be interference between the two phages in co-inoculation, neither phage out-competes the other.