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Generation of isogenic K54 capsule‐deficient Escherichia coli strains through Tn pho A‐mediated gene disruption
Author(s) -
Russo Thomas A.,
Guenther Jane E.,
Wenderoth Suzanne,
Frank Michael M.
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb01696.x
Subject(s) - biology , mutant , capsule , escherichia coli , gene , microbiology and biotechnology , transposable element , bacteriophage , transduction (biophysics) , genetics , biochemistry , botany
Summary Transposon muta genesis, using IS50 L ::phoA(Tn‐ pho A), was performed in a K54/O4/H5 blood isolate of Escherichia coli (CP9), to generate a library of random mutants. Five hundred and twenty‐six independent CP9 Tn phoA mutants were isolated with active gene fusions to alkaline phosphatase. From this mutant library, eight capsule‐deficient strains were detected and were found to have a single copy of Tn phoA. Sixteen additional capsule deficient mutants with Tn phoA inserts were subsequently obtained that did not possess active PhoA fusions. In conjunction with the initial eight capsule‐deficient isolates we have defined genes on three different Xba I fragments as being involved in capsule production. Generalized transduction with the bacteriophage T4 established that these insertions were responsible for the loss of capsule and that they are linked. These capsule‐deficient strains can be used to assess the pathogenic role of the K54 capsular polysaccharide.