A negative-control experiment series where phage host bacterial cells were pretreated with bovine serum albumin (BSA) showed no significant differences in phage titers, whereas coincubation with APK2_gp43, APK32_gp46, APK37_gp44, APK44_gp44, APK48_gp43, APK87_gp48, APK89_gp46, and APK116_gp43 resulted in A. baumannii host cells becoming nonsusceptible to infection by the corresponding phages. Here, SERPINH1 is linked to infection.