Restriction map of the antibiotic resistance plasmid R1 drd-19 and its derivatives pKN102 (R1drd-19B2) and R1drd-16 for the enzymes BamHI, HindIII, EcoRI and SalI

Abstract

The conjugative R plasmid R1drd-19, mediating antibiotic resistance to ampicillin (Ap), chloramphenicol (Cm), kanamycin (Km), streptomycin (Sm) and sulfonamides (Su) was mapped using the restriction endonucleases BamHI, HindIII, EcoRI and SalI. BamHI generates 5 fragments (A-E) with molecular weights between 46 x 10(6) 0.25 x 10(6) dalton, and HindIII 8(A-H) between 42 x 10(6) dalton (representing mainly the RTF) and 0.25 x 10(6) dalton (representing the main part of the RTF) and 0.1 x 10(6) dalton. EcoRI recognises 17 sites and produces fragments (A-Q) with molecular weights between 11.7 and 0.1 x 10(6) dalton. SalI yields 7 fragments (A-G) of 16.5 to 2.0 x 10(6) dalton. A physical map was constructed from fragments obtained by partial digestion of R1drd-19 with one restriction enzyme, by double and triple digestion of the DNA with two or three enzymes with and without isolation of individual bands from preparative gels. In addition the restriction patterns of several mutants of R1drd-19 were compared with it. Evidence is presented which indicates that the derivatives of R1 investigated are generated by extended deletions, namely the copy mutant pKN102 which has lost the Km resistance, R1drd-16, which has lost all resistances other than Km and the Kms derivative of R1drd-16, which represents the pure RTF. The map of R1drd-19 is remarkably different from those of R100 and R6-5. Its molecular weight was estimated to be 62.5 Md. The circular fragment order for BamHI is: A-C-B-D-E, for HindIII: A-D-C-B-F-H-E-G, for EcoRI: A-C-K-B-F-J-O-D-H-L-G-P-Q-N-I-E-M- and for SalI A-B-C-D-G-F-E.

Competition favours reduced cost of plasmids to host bacteria

“…E. coli were the K12-derived strain XK1502 (Panicker and Minkley, 1985). Plasmids were wild-type R1 (IncFII, transfer-proficient, fin þ Kan R Cml R ) and the R1-derived R1-16 (IncFII, transfer-proficient, fin À Kan R Cml S ) (Blohm and Goebel, 1978). R1-16 carries the R1 surface exclusion system (Bayer et al, 1995); we verified that R1 cannot efficiently conjugate into and be maintained in cells carrying R1-16 (data not shown).…”

The role of the hok/sok locus in bacterial response to stressful growth conditions

“…This plasmid stabilizing activity was subsequently characterized and found to localize on the parB region of the R1 plasmid [5]. The R1 plasmid carries several genes that encode resistance traits and in this way is able to impart multi-drug/antibiotic (ampicillin, chloramphenicol, kanamycin, streptomycin and sulphonamides) resistance to its host bacteria [6][7][8]. In addition to being found in plasmids, hok/sok loci have also been identified in the chromosomes of enterobacteria [9].…”

Composite IS1-tetracycline resistance elements in aerobactin-encoding FIme plasmids from epidemic Salmonella wien

“…It is an IncFII conjugative 69-kb derivative of Rldrd-19 which has lost all resistance determinants except for the kanamycin resistance (Km') determinant. It is virtually identical with Rldrd-16 (3,6). pZM61 (Tra-; 146 kb) and pZM33 (Tra+; 152 kb) are aerobactin-encoding FIme reference plasmids isolated from S. wien WZM6 and WZM3, respectively (4,7,17).…”