Tetracycline-resistance encoding plasmids from Paenibacillus larvae, the causal agent of American foulbrood disease, isolated from commercial honeys. - Related Documents




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306101.0000Tetracycline-resistance encoding plasmids from Paenibacillus larvae, the causal agent of American foulbrood disease, isolated from commercial honeys. Paenibacillus larvae, the causal agent of American foulbrood disease in honeybees, acquires tetracycline-resistance via native plasmids carrying known tetracycline-resistance determinants. From three P. larvae tetracycline-resistant strains isolated from honeys, 5-kb-circular plasmids with almost identical sequences, designated pPL373 in strain PL373, pPL374 in strain PL374, and pPL395 in strain PL395, were isolated. These plasmids were highly similar (99%) to small tetracycline-encoding plasmids (pMA67, pBHS24, pBSDMV46A, pDMV2, pSU1, pAST4, and pLS55) that replicate by the rolling circle mechanism. Nucleotide sequences comparisons showed that pPL373, pPL374, and pPL395 mainly differed from the previously reported P. larvae plasmid pMA67 in the oriT region and mob genes. These differences suggest alternative mobilization and/or conjugation capacities. Plasmids pPL373, pPL374, and pPL395 were individually transferred by electroporation and stably maintained in tetracycline-susceptible P. larvae NRRL B-14154, in which they autonomously replicated. The presence of nearly identical plasmids in five different genera of gram-positive bacteria, i.e., Bhargavaea, Bacillus, Lactobacillus, Paenibacillus, and Sporosarcina, inhabiting diverse ecological niches provides further evidence of the genetic transfer of tetracycline resistance among environmental bacteria from soils, food, and marine habitats and from pathogenic bacteria such as P. larvae.201425296446
301710.9964The ancient small mobilizable plasmid pALWED1.8 harboring a new variant of the non-cassette streptomycin/spectinomycin resistance gene aadA27. The small mobilizable plasmid pALWED1.8 containing a novel variant of the streptomycin/spectinomycin resistance gene aadA27 was isolated from the permafrost strains of Acinetobacter lwoffii. The 4135bp plasmid carries mobА and mobC genes that mediate its mobilization by conjugative plasmids. The nucleotide sequences of mobА and mobC are similar to those of mobilization genes of the modern plasmid pRAY* and its variants, which contain aadB gene, and are widespread among the pathogenic strains of Acinetobacter baumannii. Almost identical pALWED1.8 variants were detected in modern environmental Аcinetobacter strains. A highly similar plasmid was revealed in a strain of Acinetobacter parvus isolated from mouse intestine. Furthermore, we discovered six previously unidentified variants of plasmids related to pALWED1.8 and pRAY* in public databases. In contrast to most known variants of aadA which are cassette genes associated with integrons, the aadA27 variant harbored by pALWED1.8 is a non-cassette, autonomously transcribed gene. Non-cassette aadA genes with 96% sequence identity to aadA27 were detected in the chromosomes of Acinetobacter gyllenbergii and several uncharacterized strains of Аcinetobacter sp. Moreover, we revealed that the autonomous aadA-like genes are present in the chromosomes of many gram-positive and gram-negative bacteria. The phylogenetic analysis of amino acid sequences of all identified AadA proteins showed the following: (i) cassette aadA genes form a separate monophyletic group and mainly reside on plasmids and (ii) chromosomal non-cassette aadA genes are extremely diverse and can be inherited both vertical and via horizontal gene transfer.201626896789
301820.9960The large Bacillus plasmid pTB19 contains two integrated rolling-circle plasmids carrying mobilization functions. Plasmid pTB19 is a 27-kb plasmid originating from a thermophilic Bacillus species. It was shown previously that pTB19 contains an integrated copy of the rolling-circle type plasmid pTB913. Here we describe the analysis of a 4324-bp region of pTB19 conferring resistance to tetracycline. The nucleotide sequence of this region revealed all the characteristics of a second plasmid replicating via the rolling-circle mechanism. This sequence contained (i) the tetracycline resistance marker of pTB19, which is highly similar to other tetL-genes of gram-positive bacteria; (ii) a hybrid mob gene, which bears relatedness to both the mob-genes of pUB110 and pTB913; (iii) a palU type minus origin identical to those of pUB110 and pTB913; and (iv) a plus origin of replication similar to that of pTB913. A repB-type replication initiation gene sequence identical to that of pTB913 was present, which lacked the middle part (492 bp), thus preventing autonomous replication of this region. The hybrid mob gene was functional in conjugative mobilization of plasmids between strains of Bacillus subtilis.19911946749
586430.9959Characterization of the tetracycline resistance plasmid pMD5057 from Lactobacillus plantarum 5057 reveals a composite structure. The 10,877bp tetracycline resistance plasmid pMD5057 from Lactobacillus plantarum 5057 was completely sequenced. The sequence revealed a composite structure containing DNA from up to four different sources. The replication region had homology to other plasmids of lactic acid bacteria while the tetracycline resistance region, containing a tet(M) gene, had high homology to sequences from Clostridium perfringens and Staphylococcus aureus. Within the tetracycline resistance region a Lactobacillus IS-element was found. The remaining part of the plasmid contained three open reading frames with unknown functions. The composite structure with several truncated genes suggests a recent assembly of the plasmid. This is the first sequence of an antibiotic resistance plasmid isolated from L. plantarum.200212383727
304140.9959pCERC1, a small, globally disseminated plasmid carrying the dfrA14 cassette in the strA gene of the sul2-strA-strB gene cluster. Commensal Escherichia coli from healthy adult humans were screened for antibiotic resistance genes. Two unrelated strains contained the sul2 sulphonamide resistance gene and strAB streptomyicn resistance genes with the dfrA14 trimethoprim resistance gene cassette in the strA gene and conferred resistance to trimethoprim and sulphamethoxazole. A 6.8 kb plasmid, pCERC1, that contains these resistance genes was recovered and sequenced. Deletions were constructed, and the pCERC1 replication region was confined to a 1 kb segment carrying genes for RNAs that are closely related to the ColE1 replication initiation RNAs. Polymerase chain reaction assays, developed to detect the sul2-strA-strB gene cluster in this context, identified a streptomycin and sulphonamide resistance plasmid, pCERC2, identical to pCERC1 without the dfrA14 cassette in two further E. coli isolates. Bioinformatic analysis revealed plasmids similar to pCERC1 and two more members of this family. One, the probable progenitor, carries only the sul2 gene adjacent to the small mobile element CR2. The other has a variant resistance gene cluster that has evolved from pCERC2 via acquisition of the tet(A) tetracycline resistance determinant. pCERC1 and pCERC2 have been detected in many countries, indicating a global distribution and appear to have been circulating in Gram-negative bacteria for more than 25 years.201222416992
49350.9958Mercury resistance transposons of gram-negative environmental bacteria and their classification. A total of 29 mercury resistance transposons were isolated from mercury-resistant environmental strains of proteobacteria collected in different parts of Eurasia and the USA and tested for hybridization with probes specific for transposase genes of known mercury resistance transposons. 9 were related to Tn21 in this test, 12 were related to Tn5053, 4 to Tn5041 and 1 to Tn5044; three transposons were negative in this test. Restriction mapping and DNA sequencing revealed that 12 transposons were identical or nearly identical to their corresponding relatives while the rest showed varying divergence from their closest relatives. Most of these previously unknown transposons apparently arose as a result of homologous or site-specific recombination. One of these, Tn5046, was completely sequenced, and shown to be a chimera with the mer operon and the transposition module derived from the transposons related to Tn5041 and to Tn5044, respectively. Transposon Tn5070, showing no hybridization with the specific probes used in this study, was also completely sequenced. The transposition module of Tn5070 was most closely related to that of Tn3 while the mer operon was most closely related to that of plasmid pMERPH. The merR of Tn5070 is transcribed in the same direction as the mer structural genes, which is typical for mer operons of gram-positive bacteria. Our data suggest that environmental bacteria may harbor many not yet recognized mercury resistance transposons and warrant their further inventory.200111763242
301660.9958Complete nucleotide sequence of the conjugative tetracycline resistance plasmid pFBAOT6, a member of a group of IncU plasmids with global ubiquity. This study presents the first complete sequence of an IncU plasmid, pFBAOT6. This plasmid was originally isolated from a strain of Aeromonas caviae from hospital effluent (Westmorland General Hospital, Kendal, United Kingdom) in September 1997 (G. Rhodes, G. Huys, J. Swings, P. McGann, M. Hiney, P. Smith, and R. W. Pickup, Appl. Environ. Microbiol. 66:3883-3890, 2000) and belongs to a group of related plasmids with global ubiquity. pFBAOT6 is 84,748 bp long and has 94 predicted coding sequences, only 12 of which do not have a possible function that has been attributed. Putative replication, maintenance, and transfer functions have been identified and are located in a region in the first 31 kb of the plasmid. The replication region is poorly understood but exhibits some identity at the protein level with replication proteins from the gram-positive bacteria Bacillus and Clostridium. The mating pair formation system is a virB homologue, type IV secretory pathway that is similar in its structural organization to the mating pair formation systems of the related broad-host-range (BHR) environmental plasmids pIPO2, pXF51, and pSB102 from plant-associated bacteria. Partitioning and maintenance genes are homologues of genes in IncP plasmids. The DNA transfer genes and the putative oriT site also exhibit high levels of similarity with those of plasmids pIPO2, pXF51, and pSB102. The genetic load region encompasses 54 kb, comprises the resistance genes, and includes a class I integron, an IS630 relative, and other transposable elements in a 43-kb region that may be a novel Tn1721-flanked composite transposon. This region also contains 24 genes that exhibit the highest levels of identity to chromosomal genes of several plant-associated bacteria. The features of the backbone of pFBAOT6 that are shared with this newly defined group of environmental BHR plasmids suggest that pFBAOT6 may be a relative of this group, but a relative that was isolated from a clinical bacterial environment rather than a plant-associated bacterial environment.200415574953
303670.9958Complete nucleotide sequences of 84.5- and 3.2-kb plasmids in the multi-antibiotic resistant Salmonella enterica serovar Typhimurium U302 strain G8430. The multi-antibiotic resistant (MR) Salmonella enterica serovar Typhimurium phage type U302 strain G8430 exhibits the penta-resistant ACSSuT-phenotype (ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline), and is also resistant to carbenicillin, erythromycin, kanamycin, and gentamicin. Two plasmids, 3.2- and 84.5-kb in size, carrying antibiotic resistance genes were isolated from this strain, and the nucleotide sequences were determined and analyzed. The 3.2-kb plasmid, pU302S, belongs to the ColE1 family and carries the aph(3')-I gene (Kan(R)). The 84.5-kb plasmid, pU302L, is an F-like plasmid and contains 14 complete IS elements and multiple resistance genes including aac3, aph(3')-I, sulII, tetA/R, strA/B, bla(TEM-1), mph, and the mer operon. Sequence analyses of pU302L revealed extensive homology to various plasmids or transposons, including F, R100, pHCM1, pO157, and pCTX-M3 plasmids and TnSF1 transposon, in regions involved in plasmid replication/maintenance functions and/or in antibiotic resistance gene clusters. Though similar to the conjugative plasmids F and R100 in the plasmid replication regions, pU302L does not contain oriT and the tra genes necessary for conjugal transfer. This mosaic pattern of sequence similarities suggests that pU302L acquired the resistance genes from a variety of enteric bacteria and underscores the importance of a further understanding of horizontal gene transfer among the enteric bacteria.200716828159
304480.9958RSF1010 and a conjugative plasmid contain sulII, one of two known genes for plasmid-borne sulfonamide resistance dihydropteroate synthase. The nucleotide sequence of the type II sulfonamide resistance dihydropteroate synthase (sulII) gene was determined. The molecular weight determined by maxicells was 30,000, and the predicted molecular weight for the polypeptide was 28,469. Comparison with the sulI gene encoded by Tn21 showed 57% DNA similarity. The sulII-encoded polypeptide has 138 of 271 amino acids in common with the polypeptide encoded by sulI. The sulII gene is located on various IncQ (broad-host-range) plasmids and other small nonconjugative resistance plasmids. Detailed restriction maps were constructed to compare the different plasmids in which sulII is found. The large conjugative plasmid pGS05 and the IncQ plasmid RSF1010 contained identical nucleotide sequences for the sulII gene. This type of sulfonamide resistance is very frequently found among gram-negative bacteria because of its efficient spread to various plasmids.19883075438
45490.9958Nucleotide sequences and comparison of two large conjugative plasmids from different Campylobacter species. Two large tetracycline resistance (TcR) plasmids have been completely sequenced, the pTet plasmid (45.2 kb) from Campylobacter jejuni strain 81-176 and a plasmid pCC31 (44.7 kb) from Campylobacter coli strain CC31 that was isolated from a human case of severe gastroenteritis in the UK. Both plasmids are mosaic in structure, having homologues of genes found in a variety of different commensal and pathogenic bacteria, but nevertheless, showed striking similarities in DNA sequence and overall gene organization. Several predicted proteins encoded by genes involved in conjugation showed highest homology to proteins found in Actinobacillus actinomycetemcomitans, a periodontal pathogen. In addition to replication- and conjugation-associated genes, both plasmids carried a tet(O) gene encoding tetracycline resistance, a 6 kb ORF encoding a putative methylase and a number of genes of unknown function. The pTet plasmid co-exists in C. jejuni strain 81-176 with a smaller, previously characterized, non-conjugative plasmid pVir that also encodes a type IV secretion system (T4SS) that may affect virulence. In contrast, the T4SS encoded by pTet and pCC31 are shown to mediate bacterial conjugation between Campylobacter. The possible origin and evolution of pCC31 and pTet is discussed.200415470128
3035100.9958Molecular characterization of plasmids with antimicrobial resistant genes in avian isolates of Pasteurella multocida. The complete nucleotide sequences of two plasmids from avian isolates of Pasteurella multocida that caused outbreaks of fowl cholera in Taiwan were determined. The entire sequences of the two plasmids, designated as pJR1 and pJR2, were 6792 bp and 5252 bp. Sequence analysis showed that the plasmid pJR1 contained six major genes: the first gene (sulII) encoded a type II sulfonamide resistant dihydropteroate synthase, the second gene (tetG) encoded a tetracycline resistance protein, the third gene (catB2) encoded a chloramphenicol acetyltransferase, the fourth gene (rep) encoded a replication protein, and the fifth and sixth genes (mbeCy and deltambeAy) encoded proteins involved in the mobilization of plasmid. The plasmid pJR2 contained five major genes: the first gene (deltaintI1) encoded a truncated form of a type I integrase, the second gene (aadA1) encoded an aminoglycoside adenylyltransferase that confers resistance to streptomycin and spectinomycin, the third gene (blaP1) encoded a beta-lactamase that confers resistance to ampicillin and carbenicillin, and the fourth and fifth genes might encode proteins involved in the plasmid replication or segregation. Sequence comparisons showed that the antibiotic resistance genes found in pJR1 and pJR2 exhibited a high degree of sequence homology to the corresponding genes found in a great variety of gram-negative bacteria, including Escherichia coli, Salmonella enterica Typhimurium DT104, Psedomonas spp., P. multocida, Mannheimia spp., and Actinobacills pleuropneumoniae, which suggests that these resistance genes were disseminated in these bacteria. Although sulII and tetG genes were found previously in P. multocida or Mannheimia spp., this is the first report on the presence of catB2, aadA1, and blaP1 genes in bacteria of the family Pasturellaceae. Moreover, the aadA1 and blaP1 genes found in pJR2 were organized into an integron structure, which is a site-specific recombination system capable of capturing and mobilizing antibiotic resistance genes. This is also the first report on the presence of an integron in bacteria of the family Pasteurellaceae. The presence of a P. multocida integron might facilitate the spreading of antibiotic resistance genes between P. multocida and other gram-negative bacteria.200314708986
3010110.9957Identification of mcr-1 and a novel chloramphenicol resistance gene catT on an integrative and conjugative element in an Actinobacillus strain of swine origin. The aim of this study was to characterize a mcr-1-carrying integrative and conjugative element (ICE) in a novel Pasteurellaceae-like bacteria of swine origin. The mcr-1-positive GY-402 strain, recovered from a pig fecal sample, was subjected to whole genome sequencing with the combination of Illumina Hiseq and MinION platforms. Genome-based taxonomy revealed that strain GY-402 exhibited highest ANI value (84.89 %) to Actinobacillus succinogenes, which suggested that it represented a novel Actinobacillus species. Sequence analysis revealed that mcr-1 was clustered with eight other resistance genes in the MDR region of a novel ICE element, named ICEAsp1. Inverse PCR and mating assays showed that ICEAsp1 is active and transferrable. In addition, six circular forms mediated by four ISApl1 elements were detected with different inverse PCR sets, indicating that flexible composite transposons could be formed by pairwise combinations of multiple IS copies. Cloning experiment and phylogenetic analysis revealed that the novel Cat protein, designated CatT, belongs to type-A family and confers resistance to chloramphenicol. In conclusion, this is, to the best of our knowledge, the first report of mcr-1 gene on ICE structure and also in Pasteurellaceae bacteria. The diverse composite transposons mediated by multicopy IS elements may facilitate the dissemination of different resistance genes.202133486327
3039120.9957Distinct recent lineages of the strA- strB streptomycin-resistance genes in clinical and environmental bacteria. We report the linkage of the strA-strB streptomycin-resistance genes with Class 1 integron sequences on pSTR1, a 75-kb multiple antibiotic-resistance plasmid from Shigella flexneri. strA-strB had previously been detected only within Tn 5393, a Tn 3-family transposon, and on small nonconjugative broad-host-range plasmids such as RSF1010. The geographic range of Tn 5393 was also extended to Pseudomonas spp. isolated from apple trees in New Zealand and soil in the USA. Comparative sequence analyses indicated that strA-strB from Tn 5393 and nonconjugative plasmids constitute distinct recent lineages with strA-strB from pSTR1 intermediate between the other two. The carriage of strA-strB within an integron, a transposon, and on broad-host-range plasmids has facilitated the world-wide dissemination of this determinant among at least 21 bacterial genera.200212029529
4530130.9957Novel conjugative transferable multiple drug resistance plasmid pAQU1 from Photobacterium damselae subsp. damselae isolated from marine aquaculture environment. The emergence of drug-resistant bacteria is a severe problem in aquaculture. The ability of drug resistance genes to transfer from a bacterial cell to another is thought to be responsible for the wide dissemination of these genes in the aquaculture environment; however, little is known about the gene transfer mechanisms in marine bacteria. In this study, we show that a tetracycline-resistant strain of Photobacterium damselae subsp. damselae, isolated from seawater at a coastal aquaculture site in Japan, harbors a novel multiple drug resistance plasmid. This plasmid named pAQU1 can be transferred to Escherichia coli by conjugation. Nucleotide sequencing showed that the plasmid was 204,052 base pairs and contained 235 predicted coding sequences. Annotation showed that pAQU1 did not have known repA, suggesting a new replicon, and contained seven drug resistance genes: bla(CARB-9)-like, floR, mph(A)-like, mef(A)-like, sul2, tet(M) and tet(B). The plasmid has a complete set of genes encoding the apparatus for the type IV secretion system with a unique duplication of traA. Phylogenetic analysis of the deduced amino acid sequence of relaxase encoded by traI in pAQU1 demonstrated that the conjugative transfer system of the plasmid belongs to MOB(H12), a sub-group of the MOB(H) plasmid family, closely related to the IncA/C type of plasmids and SXT/R391 widely distributed among species of Enterobacteriaceae and Vibrionaceae. Our data suggest that conjugative transfer is involved in horizontal gene transfer among marine bacteria and provide useful insights into the molecular basis for the dissemination of drug resistance genes among bacteria in the aquaculture environment.201222446310
1794140.9956Insights into the evolution of gene organization and multidrug resistance from Klebsiella pneumoniae plasmid pKF3-140. Plasmid-mediated transfer of drug-resistance genes among various bacterial species is considered one of the most important mechanisms for the spread of multidrug resistance. To gain insights into the evolution of gene organization and antimicrobial resistance in clinical bacterial samples, a complete plasmid genome of Klebsiella pneumoniae pKF3-140 is determined, which has a circular chromosome of 147,416bp in length. Among the 203 predicted genes, 142 have function assignment and about 50 appear to be involved in plasmid replication, maintenance, conjugative transfer, iron acquisition and transport, and drug resistance. Extensive comparative genomic analyses revealed that pKF3-140 exhibits a rather low sequence similarity and structural conservation with other reported K. pneumoniae plasmids. In contrast, the overall organization of pKF3-140 is highly similar to Escherichia coli plasmids p1ESCUM and pUTI89, which indicates the possibility that K. pneumoniae pKF3-140 may have a potential origin in E. coli. Meanwhile, interestingly, several drug resistant genes show high similarity to the plasmid pU302L in Salmonella enterica serovar Typhimurium U302 strain G8430 and the plasmid pK245 in K. pneumoniae. This mosaic pattern of sequence similarities suggests that pKF3-140 might have arisen from E. coli and acquired the resistance genes from a variety of enteric bacteria and underscores the importance of a further understanding of horizontal gene transfer among enteric bacteria.201323402892
3009150.9956Identification of a novel conjugative plasmid carrying the multiresistance gene cfr in Proteus vulgaris isolated from swine origin in China. The multiresistance gene cfr has a broad host range encompassing both Gram-positive and Gram-negative bacteria, and can be located on the chromosomes or on plasmids. In this study, a novel conjugative plasmid carrying cfr, designated as pPvSC3, was characterized in a Proteus vulgaris strain isolated from swine in China. Plasmid pPvSC3 is 284,528 bp in size and harbors 10 other antimicrobial resistance genes, making it a novel plasmid that differs from all known plasmids due to its unique backbone and repA gene. BLAST analysis of the plasmid sequence shows no significant homology to any known plasmid backbone, but shows high level homology to Providencia rettgeri strain CCBH11880 Contig_9, a strain isolated from surgical wound in Brazil, 2014. There are two resistance-determining regions in pPvSC3, a cfr-containing region and a multidrug-resistant (MDR) region. The cfr-containing region is flanked by IS26, which could be looped out via IS26-mediated recombination. The MDR region harbors 10 antimicrobial resistance genes carried by various DNA segments that originated from various sources. Plasmid pPvSC3 could be successfully transferred to Escherichia coli by conjugation. In summary, we have characterized a novel conjugative plasmid pPvSC3 carrying the multiresistance gene cfr and 10 other antimicrobial resistance genes, and consider that this novel type of plasmid deserves attention.201931499097
3012160.9956Characterization of the IncA/C plasmid pSCEC2 from Escherichia coli of swine origin that harbours the multiresistance gene cfr. OBJECTIVES: To determine the complete nucleotide sequence of the multidrug resistance plasmid pSCEC2, isolated from a porcine Escherichia coli strain, and to analyse it with particular reference to the cfr gene region. METHODS: Plasmid pSCEC2 was purified from its E. coli J53 transconjugant and then sequenced using the 454 GS-FLX System. After draft assembly, predicted gaps were closed by PCR with subsequent sequencing of the amplicons. RESULTS: Plasmid pSCEC2 is 135 615 bp in size and contains 200 open reading frames for proteins of ≥100 amino acids. Analysis of the sequence of pSCEC2 revealed two resistance gene segments. The 4.4 kb cfr-containing segment is flanked by two IS256 elements in the same orientation, which are believed to be involved in the dissemination of the rRNA methylase gene cfr. The other segment harbours the resistance genes floR, tet(A)-tetR, strA/strB and sul2, which have previously been found on other IncA/C plasmids. Except for these two resistance gene regions, the pSCEC2 backbone displayed >99% nucleotide sequence identity to that of other IncA/C family plasmids isolated in France, Chile and the USA. CONCLUSIONS: The cfr gene was identified on an IncA/C plasmid, which is well known for its broad host range and transfer and maintenance properties. The location on such a plasmid will further accelerate the dissemination of cfr and co-located resistance genes among different Gram-negative bacteria. The genetic context of cfr on plasmid pSCEC2 underlines the complexity of cfr transfer events and confirms the role that insertion sequences play in the spread of cfr.201424013193
3572170.9956Comparative analysis of sequences flanking tet(W) resistance genes in multiple species of gut bacteria. tet(W) is one of the most abundant tetracycline resistance genes found in bacteria from the mammalian gut and was first identified in the rumen anaerobe Butyrivibrio fibrisolvens 1.230, where it is highly mobile and its transfer is associated with the transposable chromosomal element TnB1230. In order to compare the genetic basis for tet(W) carriage in different bacteria, we studied sequences flanking tet(W) in representatives of seven bacterial genera originating in diverse gut environments. The sequences 657 bp upstream and 43 bp downstream of tet(W) were 96 to 100% similar in all strains examined. A common open reading frame (ORF) was identified downstream of tet(W) in five different bacteria, while another conserved ORF that flanked tet(W) in B. fibrisolvens 1.230 was also present upstream of tet(W) in a human colonic Roseburia isolate and in another rumen B. fibrisolvens isolate. In one species, Bifidobacterium longum (strain F8), a novel transposase was located within the conserved 657-bp region upstream of tet(W) and was flanked by imperfect direct repeats. Additional direct repeats 6 bp long were identified on each end of a chromosomal ORF interrupted by the insertion of the putative transposase and the tet(W) gene. This tet(W) gene was transferable at low frequencies between Bifidobacterium strains. A putative minielement carrying a copy of tet(W) was identified in B. fibrisolvens transconjugants that had acquired the tet(W) gene on TnB1230. Several different mechanisms, including mechanisms involving plasmids and conjugative transposons, appear to be involved in the horizontal transfer of tet(W) genes, but small core regions that may function as minielements are conserved.200616870752
3015180.9956Genetic structure and biological properties of the first ancient multiresistance plasmid pKLH80 isolated from a permafrost bacterium. A novel multidrug-resistance plasmid, pKLH80, previously isolated from Psychrobacter maritimus MR29-12 found in ancient permafrost, was completely sequenced and analysed. In our previous studies, we focused on the pKLH80 plasmid region containing streptomycin and tetracycline resistance genes, and their mobilization with an upstream-located ISPpy1 insertion sequence (IS) element. Here, we present the complete sequence of pKLH80 and analysis of its backbone genetic structure, including previously unknown features of the plasmid's accessory region, notably a novel variant of the β-lactamase gene blaRTG-6. Plasmid pKLH80 was found to be a circular 14 835 bp molecule that has an overall G+C content of 40.3 mol% and encodes 20 putative ORFs. There are two distinctive functional modules within the plasmid backbone sequence: (i) the replication module consisting of repB and the oriV region; and (ii) the mobilization module consisting of mobA, mobC and oriT. All of the aforementioned genes share sequence identities with corresponding genes of different species of Psychrobacter. The plasmid accessory region contains antibiotic resistance genes and IS elements (ISPsma1 of the IS982 family, and ISPpy1 and ISAba14 of the IS3 family) found in environmental and clinical bacterial strains of different taxa. We revealed that the sequences flanking blaRTG-6 and closely related genes from clinical bacteria are nearly identical. This fact suggests that blaRTG-6 from the environmental strain of Psychrobacter is a progenitor of blaRTG genes of clinical bacteria. We also showed that pKLH80 can replicate in different strains of Acinetobacter and Psychrobacter genera. The roles of IS elements in the horizontal transfer of antibiotic resistance genes are examined and discussed.201425063046
5871190.9956Plasmid-mediated florfenicol resistance in Pasteurella trehalosi. OBJECTIVES: A florfenicol-resistant Pasteurella trehalosi isolate from a calf was investigated for the presence and the location of the gene floR. METHODS: The P. trehalosi isolate 13698 was investigated for its in vitro susceptibility to antimicrobial agents and its plasmid content. A 14.9 kb plasmid, designated pCCK13698, was identified by transformation into Pasteurella multocida to mediate resistance to florfenicol, chloramphenicol and sulphonamides. The plasmid was sequenced completely and analysed for its structure and organization. RESULTS: Plasmid pCCK13698 exhibited extended similarity to plasmid pHS-Rec from Haemophilus parasuis including the region carrying the parA, repB, rec and int genes. Moreover, it revealed similarities to plasmid RSF1010 in the parts covering the mobC and repA-repC genes and to plasmid pMVSCS1 in the parts covering the sul2-catA3-strA gene cluster. Moreover, the floR gene area corresponded to that of transposon TnfloR. In addition, two complete insertion sequences were detected that were highly similar to IS1593 from Mannheimia haemolytica and IS26 from Enterobacteriaceae. Several potential recombination sites were identified that might explain the development of plasmid pCCK13698 by recombination events. CONCLUSIONS: The results of this study showed that in the bovine pathogen P. trehalosi, floR-mediated resistance to chloramphenicol and florfenicol was associated with a plasmid, which also carried functionally active genes for resistance to sulphonamides (sul2) and chloramphenicol (catA3). This is to the best of our knowledge the first report of resistance genes in P. trehalosi and only the second report of the presence of a florfenicol-resistance gene in target bacteria of the family Pasteurellaceae.200616670108