A clinical isolate of transposon Tn5 expressing streptomycin resistance in Escherichia coli

Abstract

The central region of transposon TnS carries three antibiotic resistance markers: neo, ble, and str. The str gene codes for a phosphotransferase that inactivates streptomycin. This activity is phenotypically expressed in several gram-negative bacteria but not in Escherichia coil. We identified a TnS variant in E. coli clinical isolates that express streptomycin resistance. This transposon carries a 6-base-pair deletion within the str gene, near the 3' end. The same kind of mutation had been previously obtained experimentally from TnS.

Bleomycin-kanamycin resistance as a marker of the presence of transposon Tn5 in clinical strains ofEscherichia coli

“…The colony hybridization test using the DNA probe containing the APH(3')II structural gene and part of the b/e gene from Tn5 was positive in all bleomycin-kanamycin (7). Although a Tn5.unlinked streptomycin resistance determinant was found on pRYCll9, an actively expressed streptomycin-resistant determinant was also detected in Tn5 (13).…”

“…Subsequently, transformants retaining bleomycin.kanamycin resistance and corresponding to each original transconjugant, were obtained in Escherichia coli RYC816 (a recA derivative of the BM21 strain). Some of them only contained the plasmid of 80 kb, which was referred to as pRYC119 (13). The colony hybridization test using the DNA probe containing the APH(3')II structural gene and part of the b/e gene from Tn5 was positive in all bleomycin-kanamycin (7).…”

Cloning of the nptII gene of Escherichia coli and construction of a recombinant strain harboring functional recA and nptII antibiotic resistance

“…The nptII gene encodes neomycin phosphotransferase II (NPTII; EC 2.7.1.95), also called aminoglycoside 3'-phosphotransferase II (APH(3')II), which inactivates by phosphorylation a range of aminoglycoside antibiotics such as kanamycin, neomycin, geneticin, and paromomycin (Berg et al, 1975;Auerswald et al, 1981;Beck et al, 1982;Genilloud et al, 1988). The neo gene of the Tn5 appears to be an excellent selection marker for vectors in prokaryotic as well as in eukaryotic systems (Herrmann et al, 1978;Rao and Rogers, 1979;Jimenez and Davies, 1980;Colbere-Garapin et al, 1981;Southern and Berg, 1982).…”

A novel approach to insertional mutagenesis of Haemophilus influenzae

“…Eight mutants defective in the production of haemocin were detected. This strategy provides an efficient mechanism for the insertional mutagenesis of H. influenzae.Generation of mutants by insertion of a transposable antibiotic marker is a useful approach in the characterization of bacterial genes in a wide range of bacterial species (9,13,17,25,33,35 (14). Although this approach is useful, the large size of Tn9O6 limits its utility as a marker for cloning the flanking DNA, which is important for further characterization of the mutagenized gene.…”