Isolation and partial characterization of an Escherichia coli mutant resistant to colicin A.

An Escherichia coli K12 mutant resistant to colicin A-CA31 apparently through loss of its receptor sites has been isolated and partially characterized. Resistance to colicin A was accompanied with a decreased sensitivity to colicins L-398 and E2-CA42, and to acridine dyes. The mutant strain displayed the same general pattern of tolerance or sensitivity as the parent strain towards eight antibiotics, colicins C, D, E1, E3, F2, F3, G, I, K, and N; phages T1, T2, T5, T6, T7, F2, lambda vir, P1kc, phi 80, and BF23; and to methylene blue, triphenyltetrazolium chloride, ethylenediaminetetraacetate (EDTA), deoxycholate, and sodium dodecyl sulfate. Conjugation and transduction experiments showed that a locus controlling resistance to colicin A-CA31 mapped at 21 min on the genetic map of this E. coli K12 strain.