CORYNEBACTERIUM STRIATUM CHLORAMPHENICOL RESISTANCE TRANSPOSON TN5564- GENETIC ORGANIZATION AND TRANSPOSITION IN CORYNEBACTERIUM-GLUTAMICUM

The clinical isolate Corynebacterium striatum M82B (formerly Corynebac terium xerosis M82B) carries the 50-kb R-plasmid pTP10 conferring resi stance to the antibiotics chloramphenicol, erythromycin, kanamycin, an d tetracycline. DNA sequence analysis of the chloramphenicol resistanc e region revealed the presence of the 4155-bp transposable element Tn5 564. The ends of Tn5564 are identical 22-bp inverted repeats flanked b y a 6-bp target site duplication. The central region of Tn5564 encodes the chloramphenicol resistance gene cmx, specifying a transmembrane c hloramphenicol efflux protein, and an open reading frame homologous to transposases of insertion sequences identified in Arthrobacter nicoti novorans and Bordetella pertussis. Furthermore, the 1715-bp insertion sequence IS1513 encoding a putative transposase of the IS30 family is an integral part of Tn5564 and is located upstream of cmx For transpos on mutagenesis, Tn5564 was transferred to Corynebacterium glutamicum o n a mobilizable Escherichia coli plasmid using RP4-mediated intergener ic conjugation. Transposition of Tn5564 in C. glutamicum occurred with a frequency of 3.3 X 10(-8) and resulted in an insertion into target sites containing the central palindromic tetranucleotide CTAG. A Tn556 4-induced mutant strain of C. glutamicum was found to carry the transp oson in the ftsZ gene region. (C) 1998 Academic Press.