title: Previously undescribed plasmids recovered from activated sludge confer tetracycline resistance and phenotypic changes to Acinetobacter oleivorans DR1.
abstract: We used culture-dependent and culture-independent methods to extract previously undescribed plasmids harboring tetracycline (TC) resistance genes from activated sludge. The extracted plasmids were transformed into naturally competent Acinetobacter oleivorans DR1 to recover a non-Escherichia coli-based plasmid. The transformed cells showed 80-100-fold higher TC resistance than the wild-type strain. Restriction length polymorphism performed using 30 transformed cells showed four different types of plasmids. Illumina-based whole sequencing of the four plasmids identified three previously unreported plasmids and one previously reported plasmid. All plasmids carried TC resistance-related genes (tetL, tetH), tetracycline transcriptional regulators (tetR), and mobilization-related genes. As per expression analysis, TC resistance genes were functional in the presence of TC. The recovered plasmids showed mosaic gene acquisition through horizontal gene transfer. Membrane fluidity, hydrophobicity, biofilm formation, motility, growth rate, sensitivity to stresses, and quorum sensing signals of the transformed cells were different from those of the wild-type cells. Plasmid-bearing cells seemed to have an energy burden for maintaining and expressing plasmid genes. Our data showed that acquisition of TC resistance through plasmid uptake is related to loss of biological fitness. Thus, cells acquiring antibiotic resistance plasmids can survive in the presence of antibiotics, but must pay ecological costs.
authors: Department of Environmental Science and Ecological Engineering, Korea University, Anam-Dong 5Ga, Seungbuk-Ku, Seoul, 136-713, Republic of Korea.
authors: Hyerim
authors: H
authors: Hong
authors: Hyeok-Jin
authors: HJ
authors: Ko
authors: In-Geol
authors: IG
authors: Choi
authors: Woojun
authors: W
authors: Park
mesh_terms: D000150:Acinetobacter / Q000235:genetics* / Q000302:isolation & purification; D000473:Alkanes / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001673:Biodegradation, Environmental; D018441:Biofilms; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D022761:Gene Transfer, Horizontal; D018384:Oxidative Stress; D010641:Phenotype; D010957:Plasmids / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D053038:Quorum Sensing; D012492:Salts / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012722:Sewage / Q000382:microbiology*; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics*
chemical_list: D000473:Alkanes; D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D012492:Salts; D012722:Sewage; D013752:Tetracycline; C007932:n-hexadecane