Restriction enzyme fingerprinting of trimethoprim resistance plasmids

Abstract

SUMMARYRestriction enzyme fingerprinting was applied to 72 transferable trimethoprim resistance plasmids to examine aspects of their epidemiology and molecular relatedness.These plasmids had previously been divided into 25 groups according to differences in mol. wts and in antimicrobial resistance determinants. Restriction enzyme fingerprinting allowed the plasmids to be further divided into 44 different groups. The groups based on molecular weight and resistance patterns often, but not invariably, corresponded with those based on restriction enzyme fingerprints. Some plasmids with the same mol. wt and resistance pattern had different digest fingerprints and conversely, although more rarely, plasmids which differed in molecular weight by as much as 10 MDa or in resistance pattern by one resistance marker, had indistinguishable fingerprints.The plasmids were initially divided into three broad categories according to which restriction enzymes gave fingerprints of 6-20 fragments. These categories differed in the molecular weights of the plasmids contained, the numbers of resistance markers, and the proportions of the plasmids which carried transposon Tn7.Some plasmids were more widespread and persistent than others with the same mol. wt and resistance pattern but with a different restriction enzyme fingerprint.Thus, application of this technique has shown the trimethoprim resistance plasmids studied to be more diverse than was indicated by determination of mol. wt and resistance pattern, and has indicated changes in the plasmid pool over the 3 years during which they were collected.

Restriction endonuclease characterization of resistant plasmids in Enterobacteriaceae isolated from children in the Sudan

“…The findings from our study confirm those of others (12,13,19) However, other studies have shown that both of these transposons may occur in isolates from the tropics and may contribute to the widespread dissemination of resistant genes between species (8,20). The number of fragments generated by single enzymes is not sufficiently discriminatory to be useful in plasmid classification, but combining the results from two different digests does provide a basis for classification.…”

“…As part of a study of antibiotic resistance in enteric flora isolated from children in Khartoum, Sudan, we have investigated the use of restriction endonuclease digestion to characterize resistant transconjugant plasmids. Resistance pattern pKc [1][2][3][4][5][6][7][8] Ap Su Tm Sm pKc9,10 TcC pKcl11 Ap Tm pKc [12][13][14][15] Tm pKc 16 Ap Tc PKc 17 Ap Su Tm Sm C pKc 18,19 ApTcSuTmSm pKc 20 Ap Su Tm pKc 21 Ap Tc Su Tm Sm C pKc 22 Ap Tc C pKc 23,24 Ap PATIENTS AND METHODS…”

Gentamicin-resistantSalmonella typhimuriumphage type 204c: molecular studies and strain diversity in a putative bovine outbreak

“…This situation is not restricted to Gm R-plasmids in S. typhimurium. Trimethoprim Rplasmids in E. coli [16] and ampicillin R-plasmids [17] show similar divergence. However, this contrasts the molecular conservation of SSPs of S. typhimurium [9], S. enteritidis and S. dublin and demonstrates that the individual plasmid components of plasmid profiles have the capacity to evolve at different rates.…”

Molecular characterization of trimethoprim resistance inShigella sonneiin Sicily

“…Plasmid DNA was extracted by the method of Kado and Liu [19]. For endonuclease restriction analysis, plasmid DNA was prepared and purified as described by Kraft and co-workers [20]. Restriction enzymes Hind III, Hind II and Cla I were used as recommended by the manufacturer (Bethesda Research Laboratories Ltd, U.S.A.).…”