I-like resistance factors with thefi+character

Abstract

SUMMARYThefi+(fertility inhibition+) property was originally described in R factors related to F (F-like factors). The originalfi−factors, in contrast, were related to the transfer factor of a colicin I factor (I-like factors). We describe here a group of R factors which arefi+but I-like. It is suggested that all the termsfi+,fi−, F-like and I-like be used in the description of transferable plasmids.