Characterization of plasmids and plasmid-borne macrolide resistance from Lactobacillus sp. strain 100-33.
Lactobacillus sp. strain 100-33 is resistant to macrolides, lincosamides, and streptogramin B-type antibiotics (MLSR) and appears to contain several major and minor plasmids. One of these plasmids, pLAR33, is approximately 18 kbp in size. When cells of strain 100-33 were protoplasted and regenerated, an MLSS isolate was derived. The derivative, designated strain ES1, contained a unique plasmid complement in which it had apparently lost the major plasmids of the parental strain, including pLAR33, and retained only a minor plasmid seen in low concentrations in strain 100-33. The MLSR determinant was cloned from plasmid DNA of strain 100-33 on a 3-kbp EcoRV fragment into pBR322 and localized to pLAR33. The determinant expressed macrolide and lincosamide resistance in Escherichia coli HB101, was localized to approximately 1 kbp on the cloned sequence, and is apparently under the control of its own promoter. MLSR electroporants were derived from strain ES1 electroporated with plasmid DNA from strain 100-33; these MLSR isolates had acquired a plasmid complement similar to that of strain 100-33, including pLAR33. Endonuclease digestion and Southern analysis of plasmid DNA from both strains indicated that the major plasmids are multimeric and deleted forms of one archetypal extrachromosomal element.
Rinckel
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Department of Microbiology, University of Tennessee, Knoxville 37996.
Savage
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D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015139:Blotting, Southern; D002872:Chromosome Deletion; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D007778:Lactobacillus / Q000187:drug effects / Q000235:genetics*; D018942:Macrolides; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009693:Nucleic Acid Hybridization; D011815:R Factors; D015183:Restriction Mapping
D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D018942:Macrolides