Characterization of two plasmids from Campylobacter jejuni isolates that carry the aphA-7 kanamycin resistance determinant.
Two small plasmids of 11.5 and 9.5 kb, each carrying an aphA-7 kanamycin phosphotransferase gene, were studied. The MICs of kanamycin for the two human Campylobacter jejuni isolates harboring the plasmids were 10,000 and 5,000 micrograms/ml, while the MICs of amikacin were 32 and 8 micrograms/ml, respectively. The MICs of gentamicin and tobramycin were less than or equal to 2 micrograms/ml for both isolates. The restriction endonuclease maps of the plasmids were similar, with the larger plasmid showing two discrete regions of additional DNA. When the aphA-7 gene from each plasmid was cloned into pBR322, the aphA-7 gene expressed the kanamycin resistance phenotype in Escherichia coli. For transformants containing the cloned aphA-7 gene, kanamycin MICs were greater than or equal to 128 micrograms/ml. The aphA-7 gene was also subcloned from the plasmid pFKT4420 into the E. coli-Streptococcus shuttle vector pDL278 and was transformed into Streptococcus gordonii Challis. For streptococcal transformants containing the novel plasmid, kanamycin MICs were 4,000 micrograms/ml. In the presence of a tetracycline resistance plasmid, both small plasmids could be mobilized during conjugal matings to Campylobacter coli recipients.
Tenover
F C
FC
Seattle Veterans Affairs Medical Center, Washington 98108.
Fennell
C L
CL
Lee
L
L
LeBlanc
D J
DJ
D000583:Amikacin / Q000494:pharmacology; D017000:Campylobacter coli / Q000187:drug effects / Q000235:genetics; D016123:Campylobacter jejuni / Q000187:drug effects / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D005839:Gentamicins / Q000494:pharmacology; D006801:Humans; D007613:Kanamycin Resistance / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D013291:Streptococcus / Q000187:drug effects / Q000235:genetics; D014031:Tobramycin / Q000494:pharmacology
D005839:Gentamicins; D000583:Amikacin; D014031:Tobramycin