Genetic and biophysical study of R plasmids conferring sulfonamide resistance in Shigella strains isolated in 1952 and 1956.
The conjugative plasmids determining sulfonamide resistance in five Shigella strains, each isolated from a different patient, have been characterized. One S. flexneri 2a strain, isolated in 1952, harbored an fi(+) plasmid of molecular weight 53 x 10(6), which specified synthesis of F-like pili and bore determinants for sulfonamide resistance (Su) and bacteriocinogeny (Col). This plasmid was compatible with plasmids of groups F(I), F(II), I(alpha), and P. A second S. flexneri 2a strain isolated in 1952 harbored an fi(-) plasmid of molecular weight 59 x 10(6), bearing the Su determinant and compatible with all plasmids tested. This strain also harbored an fi(+) group-F(II) plasmid of molecular weight 42 x 10(6), which bore the Col determinant and specified synthesis of F-like pili. Three S. dysenteriae 2 strains isolated in 1956 carried apparently identical fi(-) plasmids of molecular weight 58 x 10(6), which bore the Su determinant, could form transconjugants in Pseudomonas but not in Proteus, and were incompatible with the P-group plasmid RP4.
D001315:Australia; D001430:Bacteriocins / Q000096:biosynthesis; D002499:Centrifugation, Density Gradient; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000032:analysis; D004270:DNA, Circular / Q000032:analysis; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects; D005111:Extrachromosomal Inheritance; D008854:Microscopy, Electron; D008970:Molecular Weight; D011513:Proteus mirabilis / Q000187:drug effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012762:Shigella dysenteriae / Q000187:drug effects* / Q000378:metabolism; D012763:Shigella flexneri / Q000187:drug effects* / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology*; D013936:Thymidine; D014316:Tritium
D001430:Bacteriocins; D004269:DNA, Bacterial; D004270:DNA, Circular; D013449:Sulfonamides; D014316:Tritium; D013936:Thymidine