Plasmid conjugation
Dotaz
Zobrazit nápovědu
OBJECTIVES: In this study, we analysed field isolates of Salmonella enterica serovar Typhimurium for the presence of conjugative plasmids transferring resistances to antibiotics. METHODS: Altogether 23 strains were analysed for the presence of conjugative R-plasmids. In the case of successful conjugation, the R-plasmids were characterized by PCR for antibiotic resistance genes, integrons and replicon typing. Variable regions of integrons were sequenced. RESULTS: Conjugation and transfer of antibiotic resistance was observed in 12 strains. Conjugative plasmids in these strains belonged to the IncI1 and IncHI1 replicons and four of them transferred antibiotic resistance associated with class I integrons. In two cases, resistance to tetracycline and/or ampicillin was not transferred by conjugation to approximately 10% of the transconjugants. Detailed characterization showed that the loss of both resistances was associated with the loss of Tn3 (bla(TEM)) and Tn1721 [tet(A)] from the conjugative plasmids p9046 and p9134. However, when only the tetracycline resistance was lost, the Tn1721 was replaced with a partial sequence of rck, and with complete coding sequences of srgA, srgB, ORF7 and pefI originating from the Salmonella Typhimurium virulence plasmid. CONCLUSIONS: Two plasmids from our collection were capable of recombination with the virulence plasmid of Salmonella Typhimurium and subsequently spread both antibiotic resistance and virulence genes to the recipient.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence MeSH
- DNA bakterií genetika MeSH
- faktory virulence genetika MeSH
- financování organizované MeSH
- genotyp MeSH
- genová přestavba MeSH
- integrony MeSH
- konjugace genetická MeSH
- lidé MeSH
- plazmidy MeSH
- polymerázová řetězová reakce MeSH
- pořadí genů MeSH
- rekombinace genetická MeSH
- replikon MeSH
- Salmonella typhimurium genetika izolace a purifikace patogenita účinky léků MeSH
- syntenie MeSH
- transpozibilní elementy DNA MeSH
- virulence MeSH
- Check Tag
- lidé MeSH
- MeSH
- Escherichia coli genetika izolace a purifikace MeSH
- konjugace genetická MeSH
- lidé MeSH
- molekulární sekvence - údaje MeSH
- plazmidy genetika izolace a purifikace ultrastruktura MeSH
- R-plasmidy genetika izolace a purifikace MeSH
- restrikční mapování MeSH
- transformace genetická MeSH
- Check Tag
- lidé MeSH
The role of a 120-kb plasmid in relation to virulence and drug resistance factor in Shigella dysenteriae was studied. For characterization of plasmids, the mating system is a useful and efficient means of transferring both large and small plasmids to a new host. The conjugative transfer of a 120-kb (pCAT120) ampicillin-resistant plasmid of S. dysenteriae to E. coli K-12 was not successful. Introduction of an E. coli fertility factor plasmid F, did not help to mobilize the plasmid. Low transfer frequencies of antibiotic markers to E. coli were achieved by treatment of the donor S. dysenteriae with N-methyl-N'-nitro-N-nitrosoguanidine. The transconjugants showed resistance to ampicillin, chloramphenicol, tetracycline and cadmium. A transconjugant carrying the 120-kb plasmid of S. dysenteriae produced keratoconjunctivitis in guinea pigs. Repeated subculture of Clmr transconjugant (pCAT120) on tryptic soya agar plates became Clms and showed four distinct DNA bands ranging from 3 to 10 kb in size on agarose gel electrophoresis. Utilization of organic acids, metal resistance (Cd), dye-binding properties (Crb+, Ebr+) and drug resistance (Amp, Tet) were identified on 10, 7, 4 and 3-kb plasmid DNA fragment of pCAT120 respectively. Crb+ 4-kb DNA fragment of pCAT120 was isolated, purified and transferred to an avirulent E. coli K12 by transformation. However, transformant (pET4) showed poor growth on solid media and its growth in liquid culture was only possible after supplementation of the unknown low-molar-mass thermolabile factor(s) secreted by the recipient strain.(ABSTRACT TRUNCATED AT 250 WORDS)
Bacterial nanotubes are membranous structures that have been reported to function as conduits between cells to exchange DNA, proteins, and nutrients. Here, we investigate the morphology and formation of bacterial nanotubes using Bacillus subtilis. We show that nanotube formation is associated with stress conditions, and is highly sensitive to the cells' genetic background, growth phase, and sample preparation methods. Remarkably, nanotubes appear to be extruded exclusively from dying cells, likely as a result of biophysical forces. Their emergence is extremely fast, occurring within seconds by cannibalizing the cell membrane. Subsequent experiments reveal that cell-to-cell transfer of non-conjugative plasmids depends strictly on the competence system of the cell, and not on nanotube formation. Our study thus supports the notion that bacterial nanotubes are a post mortem phenomenon involved in cell disintegration, and are unlikely to be involved in cytoplasmic content exchange between live cells.
The gene mcr-1 conferring resistance to last-line antibiotic colistin has been reported globally. Here, we describe the first detection of plasmid-mediated colistin resistance in Russian wildlife, an isolate of Escherichia coli sequence type 2280 from a black kite (Milvus migrans) scavenging raptor. Whole-genome sequencing and plasmid transferability experiments revealed that mcr-1.1 was located on conjugative IncI2 plasmid pDR164 (59891 bp). Migratory black kites may contribute to the global spread of mobile colistin resistance.
- MeSH
- antibakteriální látky metabolismus farmakologie MeSH
- bakteriální léková rezistence genetika MeSH
- dravci mikrobiologie MeSH
- Escherichia coli účinky léků enzymologie genetika izolace a purifikace MeSH
- infekce vyvolané Escherichia coli epidemiologie mikrobiologie přenos veterinární MeSH
- kolistin metabolismus farmakologie MeSH
- migrace zvířat MeSH
- mikrobiální testy citlivosti MeSH
- plazmidy chemie metabolismus MeSH
- proteiny z Escherichia coli genetika MeSH
- sekvenování celého genomu MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Rusko MeSH
Streptomyces sioyaensis NRRL-B5408 produces a siomycin complex (a group of thiopeptide antibiotics structurally related to thiostrepton). Development of genetic tools for the detection of siomycin production and DNA transfer into this strain is described. The existing tipA-based reporter system for determination of siomycin production was modified to achieve its stable integration into actinomycete genomes. Various replicative plasmids (pKC1139, pKC1218E, pSOK101) as well as actinophage phi C31- and VWB-based vectors pSET152 and pSOK804, respectively, were conjugally transferred from E. coli into the siomycin producer at a frequency ranging from 3.7 x 10(-9) to 1.1 x 10(-5). The transconjugants did not differ from wild type in their ability to produce siomycin. There is one attB site for each integrative plasmid. The utility of temperature sensitive replicon of pKC1139 for insertional gene inactivation in S. sioyaensis has been validated by disruption of putative nonribosomal peptide synthetase gene.
- MeSH
- antibakteriální látky metabolismus MeSH
- financování organizované MeSH
- genetické vektory genetika MeSH
- klonování DNA metody MeSH
- konjugace genetická genetika MeSH
- peptidy genetika metabolismus MeSH
- plazmidy genetika MeSH
- reportérové geny MeSH
- Streptomyces genetika metabolismus MeSH
- technika přenosu genů MeSH
BACKGROUND: Conjugative plasmids play a major role in the dissemination of antibiotic resistance genes. Knowledge of the plasmid characteristics and behaviour can allow development of control strategies. Here we focus on the IncX group of plasmids carrying genes conferring quinolone resistance (PMQR), reporting their transfer and persistence within host bacteria of various genotypes under distinct conditions and levels of induced stress in form of temperature change and various concentrations of ciprofloxacin supplementation. METHODS: Complete nucleotide sequences were determined for eight qnr-carrying IncX-type plasmids, of IncX1 (3), IncX2 (3) and a hybrid IncX1-2 (2) types, recovered from Escherichia coli of various origins. This data was compared with further complete sequences of IncX1 and IncX2 plasmids carrying qnr genes (n = 41) retrieved from GenBank and phylogenetic tree was constructed. Representatives of IncX1 (pHP2) and IncX2 (p194) and their qnrS knockout mutants, were studied for influence of induced stress and genetic background on conjugative transfer and maintenance. RESULTS: A high level of IncX core-genome similarity was found in plasmids of animal, environmental and clinical origin. Significant differences were found between the individual IncX plasmids, with IncX1 subgroup plasmids showing higher conjugative transfer rates than IncX2 plasmids. Knockout of qnr modified transfer frequency of both plasmids. Two stresses applied simultaneously were needed to affect transfer rate of wildtype plasmids, whereas a single stress was sufficient to affect the IncX ΔqnrS plasmids. The conjugative transfer was shown to be biased towards the host phylogenetic proximity. A long-term cultivation experiment pointed out the persistence of IncX plasmids in the antibiotic-free environment. CONCLUSIONS: The study indicated the stimulating effect of ciprofloxacin supplementation on the plasmid transfer that can be nullified by the carriage of a single PMQR gene. The findings present the significant properties and behaviour of IncX plasmids carrying antibiotic resistance genes that are likely to play a role in their dissemination and stability in bacterial populations.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence genetika MeSH
- ciprofloxacin farmakologie MeSH
- Escherichia coli * genetika MeSH
- fylogeneze MeSH
- genomika MeSH
- konjugace genetická MeSH
- plazmidy genetika MeSH
- proteiny z Escherichia coli * genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
