# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 3562 | 0 | 0.9973 | Isolation and screening of plasmids from the epilithon which mobilize recombinant plasmid pD10. This study examined the potential of bacteria from river epilithon to mobilize a recombinant catabolic plasmid, pD10, encoding 3-chlorobenzoate degradation and kanamycin resistance. Fifty-four mobilizing plasmids were exogenously isolated by triparental matings between strains of Pseudomonas putida and epilithic bacteria from the River Taff (South Wales, United Kingdom). Frequencies for mobilization ranged from 1.7 x 10(-8) to 4.5 x 10(-3) per recipient at 20 degrees C. The sizes of the mobilizing plasmids isolated ranged from 40 kb to over 200 kb, and 19 of 54 were found to encode mercury resistance. Plasmid-encoded resistance to tetracycline and streptomycin was also found but not resistance to UV light or various heavy metals. Eight plasmids of epilithic bacteria, analyzed by comparing restriction fragmentation patterns, showed significant differences between those isolated from different independent matings. Optimal temperatures for mobilization of pD10 were between 15 and 25 degrees C. Four mercury resistance plasmids were found to be broad host range, transferring mercury resistance and mobilizing pD10 readily to representative species of beta- and gamma-purple bacteria. In general, frequencies of pD10 mobilization by plasmids of epilithic bacteria were 2 to 3 orders of magnitude lower than conjugal transfer frequencies. Thus, there is a high potential for exchange of recombinant genes introduced into the epilithon by mobilization between a variety of bacterial species. | 1992 | 1599248 |
| 3563 | 1 | 0.9971 | Transferable antibiotic resistance plasmids from biogas plant digestates often belong to the IncP-1ε subgroup. Manure is known to contain residues of antibiotics administered to farm animals as well as bacteria carrying antibiotic resistance genes (ARGs). These genes are often located on mobile genetic elements. In biogas plants (BGPs), organic substrates such as manure and plant material are mixed and fermented in order to provide energy, and resulting digestates are used for soil fertilization. The fate of plasmid carrying bacteria from manure during the fermentation process is unknown. The present study focused on transferable antibiotic resistance plasmids from digestates of seven BGPs, using manure as a co-substrate, and their phenotypic and genotypic characterization. Plasmids conferring resistance to either tetracycline or sulfadiazine were captured by means of exogenous plasmid isolation from digestates into Pseudomonas putida KT2442 and Escherichia coli CV601 recipients, at transfer frequencies ranging from 10(-5) to 10(-7). Transconjugants (n = 101) were screened by PCR-Southern blot hybridization and real-time PCR for the presence of IncP-1, IncP-1ε, IncW, IncN, IncP-7, IncP-9, LowGC, and IncQ plasmids. While 61 plasmids remained unassigned, 40 plasmids belonged to the IncP-1ε subgroup. All these IncP-1ε plasmids were shown to harbor the genes tet(A), sul1, qacEΔ1, intI1, and integron gene cassette amplicons of different size. Further analysis of 16 representative IncP-1ε plasmids showed that they conferred six different multiple antibiotic resistance patterns and their diversity seemed to be driven by the gene cassette arrays. IncP-1ε plasmids displaying similar restriction and antibiotic resistance patterns were captured from different BGPs, suggesting that they may be typical of this environment. Our study showed that BGP digestates are a potential source of transferable antibiotic resistance plasmids, and in particular the broad host range IncP-1ε plasmids might contribute to the spread of ARGs when digestates are used as fertilizer. | 2014 | 25653641 |
| 3566 | 2 | 0.9970 | Transfer of antibiotic multiresistant plasmid RP4 from escherichia coli to activated sludge bacteria. In situ transfer of a self-transmissible, antibiotic-multiresistant plasmid RP4 from a laboratory Escherichia coli strain C600 to indigenous activated sludge bacteria was investigated using filter mating. The transfer frequency of RP4 from the donor E. coli to the bacteria that was sampled from two wastewater treatment plants was 5.1x10(-2) to 7.5x10(-1) and 4.6x10(-3) to 1.3x10(-2)/potential recipient. The isolated transconjugants showed resistance to Ap, Km, and Tc and the presence of a plasmid with a similar size to RP4. The traG gene on RP4 was also detected from all transconjugants. Reverse-transfer experiments from the transconjugants to E. coli HB101 indicated that RP4 maintained self-transmissibility in the transconjugants. The transconjugant strains were dominant bacteria in activated sludge including Pseudomonas fluorescens, P. putida, and Ochrobactrum anthropi and minor populations of enteric bacterial strains including Citrobacter freundii, E. coli, Enterobacter cloacae, E. asburiae, and Klebsiella pneumoniae ssp. pneumoniae. The transconjugant strains K. pneumoniae ssp. pneumonia, E. cloacae, and E. asburiae had several naturally occurring plasmids. These results suggest that in situ transfer of plasmids and the exchange of antibiotic-resistant genes can occur between released and indigenous bacteria in activated sludge. | 2008 | 18930008 |
| 3035 | 3 | 0.9969 | Molecular 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. | 2003 | 14708986 |
| 3039 | 4 | 0.9969 | Distinct 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. | 2002 | 12029529 |
| 3016 | 5 | 0.9969 | Complete 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. | 2004 | 15574953 |
| 3572 | 6 | 0.9969 | Comparative 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. | 2006 | 16870752 |
| 3044 | 7 | 0.9969 | RSF1010 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. | 1988 | 3075438 |
| 3550 | 8 | 0.9968 | Conjugative transmission of antibiotic-resistance from stream water Escherichia coli as related to number of sulfamethoxazole but not class 1 and 2 integrase genes. A conjugation assay was used to determine the effects of phenotypic resistance to one to up to 5 antibiotics, sampling site of origin, presence or absence of class 1 and/or class 2 integrase (intI) genes (intI1 and intI2), and the number of sulfamethoxazole resistance (sul) and trimethoprim resistance (dfr) genes on the transfer frequencies of plasmids from environmental, antibiotic-resistant Escherichia coli. Of 51 sulfamethoxazole and trimethoprim-resistant E. coli isolates conferring at least one mob gene (mob(P51), mob(F11), mob(F12), mob(Q11), mob(Q12) , or mob(Qu) ), 38 produced transconjugants with an overall mean frequency of 1.60 × 10(-3) transconjugants/ donors (T/D) or 5.89 × 10(-3) transconjugants/recipients (T/R). The presence or absence of intI1 and intI2 and the presence or absence of different targeted dfr genes (dfrA1, dfrA8, dfrA12, dfrA14, dfrA17, and/or dfrB3) were not statistically related to plasmid transfer frequencies as determined by ANOVA (P ≥ 0.05). However, E. coli isolates recovered 2 km downstream of wastewater treatment plant effluent input, and those possessing resistance to 3 antibiotics had significantly greater plasmid transfer frequency than their counterparts when calculated as T/D (ANOVA followed by Fisher's least significant difference means comparison, P < 0.05). Greater plasmid transfer frequency calculated as T/D was also measured for E. coli possessing 3 compared to a single sul gene. The in-vitro frequency suggests that horizontal gene transfer of conjugative mediated-antibiotic (sul) resistance genes may be significant among resistant, stream bacteria. | 2016 | 28090382 |
| 3012 | 9 | 0.9968 | Characterization 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. | 2014 | 24013193 |
| 3552 | 10 | 0.9968 | Piggery manure used for soil fertilization is a reservoir for transferable antibiotic resistance plasmids. In this study, the prevalence and types of transferable antibiotic resistance plasmids in piggery manure were investigated. Samples from manure storage tanks of 15 farms in Germany were analysed, representing diverse sizes of herds, meat or piglet production. Antibiotic resistance plasmids from manure bacteria were captured in gfp-tagged rifampicin-resistant Escherichia coli and characterized. The occurrence of plasmid types was also detected in total community DNA by PCR and hybridization. A total of 228 transconjugants were captured from 15 manures using selective media supplemented with amoxicillin, sulfadiazine or tetracycline. The restriction patterns of 81 plasmids representing different antibiotic resistance patterns or different samples clustered into seven groups. Replicon probing revealed that 28 of the plasmids belonged to IncN, one to IncW, 13 to IncP-1 and 19 to the recently discovered pHHV216-like plasmids. The amoxicillin resistance gene bla-TEM was detected on 44 plasmids, and sulphonamide resistance genes sul1, sul2 and/or sul3 on 68 plasmids. Hybridization of replicon-specific sequences amplified from community DNA revealed that IncP-1 and pHHV216-like plasmids were detected in all manures, while IncN and IncW ones were less frequent. This study showed that 'field-scale' piggery manure is a reservoir of broad-host range plasmids conferring multiple antibiotic resistance genes. | 2008 | 18557938 |
| 3567 | 11 | 0.9967 | Cloning and sequence analysis of ermQ, the predominant macrolide-lincosamide-streptogramin B resistance gene in Clostridium perfringens. The erythromycin resistance determinant from Clostridium perfringens JIR100 has been cloned, sequenced, and shown to be expressed in Escherichia coli. An open reading frame with sequence similarity to erm genes from other bacteria was identified and designated the ermQ gene. On the basis of comparative sequence analysis, it was concluded that the ermQ gene represented a new Erm hybridization class, designated ErmQ. Genes belonging to the ErmQ class were found to be widespread in C. perfringens, since 30 of 38 macrolide-lincosamide-streptogramin B-resistant C. perfringens strains, from diverse sources, hybridized to an ermQ-specific gene probe. The ermQ gene therefore represents the most common erythromycin resistance determinant in C. perfringens. | 1994 | 8067735 |
| 3363 | 12 | 0.9967 | Spreading antibiotic resistance through spread manure: characteristics of a novel plasmid type with low %G+C content. Bioactive amounts of antibiotics as well as resistant bacteria reach the soil through manure fertilization. We investigated plasmids that may stimulate the environmental spread and interspecies transfer of antibiotic resistance. After treatment of two soils with manure, either with or without the sulfonamide antibiotic sulfadiazine, a significant increase in copies of the sulfonamide resistance gene sul2 was detected by qPCR. All sul2 carrying plasmids, captured in Escherichia coli from soil, belonged to a novel class of self-transferable replicons. Manuring and sulfadiazine significantly increased the abundance of this replicon type in a chemically fertilized but not in an annually manured soil, as determined by qPCR targeting a transfer gene. Restriction patterns and antibiograms showed a considerable diversity within this novel plasmid group. Analysis of three complete plasmid sequences revealed a conserved 30 kbp backbone with only 36% G+C content, comprised of transfer and maintenance genes with moderate homology to plasmid pIPO2 and a replication module (rep and oriV) of other descent. The plasmids differed in composition of the 27.0-28.3 kbp accessory region, each of which carried ISCR2 and several resistance genes. Acinetobacter spp. was identified as a potential host of such LowGC-type plasmids in manure and soil. | 2009 | 19055690 |
| 3009 | 13 | 0.9967 | Identification 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. | 2019 | 31499097 |
| 9965 | 14 | 0.9967 | The complete genome sequences of four new IncN plasmids from wastewater treatment plant effluent provide new insights into IncN plasmid diversity and evolution. The dissemination of antibiotic resistance genes among bacteria often occurs by means of plasmids. Wastewater treatment plants (WWTP) were previously recognized as hot spots for the horizontal transfer of genetic material. One of the plasmid groups that is often associated with drug resistance is the incompatibility group IncN. The aim of this study was to gain insights into the diversity and evolutionary history of IncN plasmids by determining and comparing the complete genome sequences of the four novel multi-drug resistance plasmids pRSB201, pRSB203, pRSB205 and pRSB206 that were exogenously isolated from the final effluent of a municipal WWTP. Their sizes range between 42,875 bp and 56,488 bp and they share a common set of backbone modules that encode plasmid replication initiation, conjugative transfer, and plasmid maintenance and control. All plasmids are transferable at high rates between Escherichia coli strains, but did not show a broad host range. Different genes conferring resistances to ampicillin, streptomycin, spectinomycin, sulfonamides, tetracycline and trimethoprim were identified in accessory modules inserted in these plasmids. Comparative analysis of the four WWTP IncN plasmids and IncN plasmids deposited in the NCBI database enabled the definition of a core set of backbone genes for this group. Moreover, this approach revealed a close phylogenetic relationship between the IncN plasmids isolated from environmental and clinical samples. Phylogenetic analysis also suggests the existence of host-specific IncN plasmid subgroups. In conclusion, IncN plasmids likely contribute to the dissemination of resistance determinants between environmental bacteria and clinical strains. This is of particular importance since multi-drug resistance IncN plasmids have been previously identified in members of the Enterobacteriaceae that cause severe infections in humans. | 2012 | 22326849 |
| 5844 | 15 | 0.9967 | Comparison of antibiotic resistance, biofilm formation and conjugative transfer of Staphylococcus and Enterococcus isolates from International Space Station and Antarctic Research Station Concordia. The International Space Station (ISS) and the Antarctic Research Station Concordia are confined and isolated habitats in extreme and hostile environments. The human and habitat microflora can alter due to the special environmental conditions resulting in microbial contamination and health risk for the crew. In this study, 29 isolates from the ISS and 55 from the Antarctic Research Station Concordia belonging to the genera Staphylococcus and Enterococcus were investigated. Resistance to one or more antibiotics was detected in 75.8 % of the ISS and in 43.6 % of the Concordia strains. The corresponding resistance genes were identified by polymerase chain reaction in 86 % of the resistant ISS strains and in 18.2 % of the resistant Concordia strains. Plasmids are present in 86.2 % of the ISS and in 78.2 % of the Concordia strains. Eight Enterococcus faecalis strains (ISS) harbor plasmids of about 130 kb. Relaxase and/or transfer genes encoded on plasmids from gram-positive bacteria like pIP501, pRE25, pSK41, pGO1 and pT181 were detected in 86.2 % of the ISS and in 52.7 % of the Concordia strains. Most pSK41-homologous transfer genes were detected in ISS isolates belonging to coagulase-negative staphylococci. We demonstrated through mating experiments that Staphylococcus haemolyticus F2 (ISS) and the Concordia strain Staphylococcus hominis subsp. hominis G2 can transfer resistance genes to E. faecalis and Staphylococcus aureus, respectively. Biofilm formation was observed in 83 % of the ISS and in 92.7 % of the Concordia strains. In conclusion, the ISS isolates were shown to encode more resistance genes and possess a higher gene transfer capacity due to the presence of three vir signature genes, virB1, virB4 and virD4 than the Concordia isolates. | 2013 | 23411852 |
| 4458 | 16 | 0.9967 | Insight into the plasmid metagenome of wastewater treatment plant bacteria showing reduced susceptibility to antimicrobial drugs analysed by the 454-pyrosequencing technology. Wastewater treatment plants (WWTPs) are a reservoir for bacteria harbouring antibiotic resistance plasmids. To get a comprehensive overview on the plasmid metagenome of WWTP bacteria showing reduced susceptibility to certain antimicrobial drugs an ultrafast sequencing approach applying the 454-technology was carried out. One run on the GS 20 System yielded 346,427 reads with an average read length of 104 bases resulting in a total of 36,071,493 bases sequence data. The obtained plasmid metagenome was analysed and functionally annotated by means of the Sequence Analysis and Management System (SAMS) software package. Known plasmid genes could be identified within the WWTP plasmid metagenome data set by BLAST searches using the NCBI Plasmid Database. Most abundant hits represent genes involved in plasmid replication, stability, mobility and transposition. Mapping of plasmid metagenome reads to completely sequenced plasmids revealed that many sequences could be assigned to the cryptic pAsa plasmids previously identified in Aeromonas salmonicida subsp. salmonicida and to the accessory modules of the conjugative IncU resistance plasmid pFBAOT6 of Aeromonas punctata. Matches of sequence reads to antibiotic resistance genes indicate that plasmids from WWTP bacteria encode resistances to all major classes of antimicrobial drugs. Plasmid metagenome sequence reads could be assembled into 605 contigs with a minimum length of 500 bases. Contigs predominantly encode plasmid survival functions and transposition enzymes. | 2008 | 18586057 |
| 2017 | 17 | 0.9967 | Prevalence and characterization of integrons from bacteria isolated from a slaughterhouse wastewater treatment plant. OBJECTIVES: To investigate the presence and distribution of integron-carrying bacteria from a slaughterhouse wastewater treatment plant (WWTP). METHODS: Enterobacteriaceae and aeromonads were isolated at different stages of the wastewater treatment process and screened for the presence of integrase genes by dot-blot hybridization. Integrase-positive strains were characterized in terms of phylogenetic affiliation, genetic content of integrons and antimicrobial resistance profiles. Plasmid location of some integrons was established by Southern-blot hybridization. Strains containing integron-carrying plasmids were selected for mating experiments. RESULTS: Integrase genes were present in all samples, including the final effluent. The global prevalence was determined to be 35%, higher than in other aquatic environments. Forty-two integrase-positive isolates were further characterized. Nine distinct cassette arrays were found, containing genes encoding resistance to beta-lactams (bla(OXA-30)), aminoglycosides (aadA1, aadA2, aadA13, aadB), streptothricin (sat1, sat2), trimethoprim (dfrA1, dfrA12), a putative esterase (estX) and a protein with unknown function (orfF). Gene cassette arrays aadA1, dfrAI-aadA1 and estX-sat2-aadA1 were common to aeromonads and Enterobacteriaceae. The class 2 integron containing an estX-sat2-aadA1 cassette array was detected for the first time in Aeromonas sp. Nearly 12% (5 out of 43) of intI genes were located in plasmids. intI genes from isolates MM.1.3 and MM.1.5 were successfully conjugated into Escherichia coli at frequencies of 3.79 x 10(-5) and 5.46 x 10(-5) per recipient cell, respectively. CONCLUSIONS: Our data support the hypothesis that WWTPs constitute a potential hot spot for horizontal gene transfer and for selection of antimicrobial resistance genes among aquatic bacteria. Moreover, water discharges represent a possible risk for dissemination of undesirable genetic traits. | 2007 | 17913715 |
| 5868 | 18 | 0.9967 | Evaluation of plasmid content and tetracycline resistance conjugative transfer in Enterococcus italicus strains of dairy origin. Five Enterococcus italicus strains harbouring tet genes responsible for the tetracycline resistance were subjected to plasmid profile determination studies. For four strains tested the profiles showed between three and six plasmid bands, the size of which ranged between 1.6 and 18.5 kb. Southern hybridization experiments associated tetS and tetK genes with chromosomal DNA in all strains and tetM gene with plasmids of around the same size (18.5 kb) in two of the tested strains. The ability of the new species to transfer tetM gene was studied by transfer experiments with the tetracycline-susceptible recipient strains E. faecalis JH2-2 and OG1RF; mobilization experiments were performed with E. faecalis JH 2-2 harbouring the conjugative plasmid pIP501as helper plasmid. The results obtained show that the new enterococcal species was able to acquire antibiotic resistance by conjugation, but not to transfer its plasmids to other bacteria. Further PCR and hybridization experiments carried out to assess the presence of mobilization sequences also suggest that the tetM plasmid from E. italicus is a non-mobilizable plasmid. | 2009 | 19484299 |
| 821 | 19 | 0.9967 | DNA probes for studying streptothricin resistance evolution in enteric bacteria. Probes for the detection of streptothricin resistance genes have been derived from recombinant plasmids. These include the streptothricin resistance gene probe sat 1/2 derived from Tn 1826 and specific for both the sat-1 determinant of Tn 1825 and the sat-2 determinant of Tn 1826, and the probe sat D derived from and specific for the sat-1 determinant of transposon Tn 1825. A third streptothricin resistance gene probe, sat 3, represents the streptothricin resistance determinant sat-3 of the IncQ R plasmid pIE639. Hybridization studies did not reveal any sequence homology between sat-3 and the transposon-localized sat-1 and sat-2 determinants. Moreover, non of the different sat-determinants isolated from plasmids of gram negative bacteria hybridized with the analogous resistance determinant of Streptomyces noursei, which had been cloned and named nat by Krügel et al. (Gene, 1988, 62, 209-214). The sat 1/2 probe in combination with the sat D probe proved to be suitable for the identification and the differentiation of sat-1 and sat-2 determinants in different genetic environments. Streptothricin resistance genes related to those present on transposons Tn 1825 and Tn 1826 have been detected by hybridization with the probe sat 1/2 on plasmids isolated a long time ago before the application of streptothricins. The sat-3 determinant appears to be exclusively associated with the IncQ plasmid pIE639. | 1990 | 2166786 |