# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 3059 | 0 | 1.0000 | Genome Analysis of Kingella kingae Strain KWG1 Reveals How a β-Lactamase Gene Inserted in the Chromosome of This Species. We describe the genome of a penicillinase-producing Kingella kingae strain (KWG1), the first to be isolated in continental Europe, whose bla(TEM-1) gene was, for the first time in this species, found to be chromosomally inserted. The bla(TEM) gene is located in an integrative and conjugative element (ICE) inserted in Met-tRNA and comprising genes that encode resistance to sulfonamides, streptomycin, and tetracycline. This ICE is homologous to resistance-conferring plasmids of K. kingae and other Gram-negative bacteria. | 2016 | 26574009 |
| 3043 | 1 | 0.9994 | The role of insertions, deletions, and substitutions in the evolution of R6 related plasmids encoding aminoglycoside transferase ANT-(2"). In 7% of gram-negative bacteria resistance to gentamicin is mainly mediated by plasmid-encoded aminoglycoside transferase ANT-(2"). The genome organization of 15 aadB plasmids (42-110 kb) was analyzed by restriction and hybridization techniques. They appeared to be IncFII-like replicons but were distinct from R6 by virtue of small substitutions in the transfer region. Aminoglycoside resistance genes aadB and aadA were located on Tn21 related elements. Only one of them was able to transpose its resistance genes mer sul aadA and aadB ( Tn4000 ), the other elements were naturally occurring defective transposons. In some of these structures deletions were identified at the termini, at sul, aadA , mer or transposition function--insertions adjacent to aadA or mer. The mode of these rearrangements and their site-specificity were considered with respect to the evolution of the Tn21 transposon family. | 1984 | 6328217 |
| 3044 | 2 | 0.9993 | 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 |
| 3041 | 3 | 0.9993 | pCERC1, 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. | 2012 | 22416992 |
| 4465 | 4 | 0.9992 | Genetic analyses of sulfonamide resistance and its dissemination in gram-negative bacteria illustrate new aspects of R plasmid evolution. In contrast to what has been observed for many other antibiotic resistance mechanisms, there are only two known genes encoding plasmid-borne sulfonamide resistance. Both genes, sulI and sulII, encode a drug-resistant dihydropteroate synthase enzyme. In members of the family Enterobacteriaceae isolated from several worldwide sources, plasmid-mediated resistance to sulfonamides could be identified by colony hybridization as being encoded by sulI, sulII, or both. The sulI gene was in all cases found to be located in the newly defined, mobile genetic element, recently named an integron, which has been shown to contain a site-specific recombination system for the integration of various antibiotic resistance genes. The sulII gene was almost exclusively found as part of a variable resistance region on small, nonconjugative plasmids. Colony hybridization to an intragenic probe, restriction enzyme digestion, and nucleotide sequence analysis of small plasmids indicated that the sulII gene and contiguous sequences represent an independently occurring region disseminated in the bacterial population. The sulII resistance region was bordered by direct repeats, which in some plasmids were totally or partially deleted. The prevalence of sulI and sulII could thus be accounted for by their stable integration in transposons and in plasmids that are widely disseminated among gram-negative bacteria. | 1991 | 1952855 |
| 4499 | 5 | 0.9992 | Organization of two sulfonamide resistance genes on plasmids of gram-negative bacteria. The organization of two widely distributed sulfonamide resistance genes has been studied. The type I gene was linked to other resistance genes, like streptomycin resistance in R100 and trimethoprim resistance in R388 and other recently isolated plasmids from Sri Lanka. In R388, the sulfonamide resistance gene was transcribed from a promoter of its own, but in all other studied plasmids the linked genes were transcribed from a common promoter. This was especially established with a clone derived from plasmid R6-5, in which transposon mutagenesis showed that expression of sulfonamide resistance was completely dependent on the linked streptomycin resistance gene. The type II sulfonamide resistance gene was independently transcribed and found on two kinds of small resistance plasmids and also on large plasmids isolated from clinical material. | 1987 | 3032095 |
| 4526 | 6 | 0.9992 | The tetracycline resistance gene tet(M) exhibits mosaic structure. Tetracycline resistance genes of the M class, tet(M), are typically found on mobile genetic elements as the conjugative transposons of gram-positive bacteria. By comparing the sequences of eight different tet(M) genes (from Enterococcus faecalis, Streptococcus pneumoniae, Staphylococcus aureus, Ureaplasma urealyticum, and Neisseria), a mosaic structure was detected which could be traced to two distinct alleles. The two alleles displayed a divergence of 8% and a different G/C content. The block structure of these genes provides evidence for the contribution of homologous recombination to the evolution and the heterogeneity of the tet(M) locus. Unlike described cases of chromosomally located mosaic loci, tet(M) is a relatively recently acquired determinant in the species examined and it would appear that mosaic structure within tet(M) has evolved after acquisition of the gene by the mobile genetic elements upon which it is located. | 1996 | 8812782 |
| 3054 | 7 | 0.9992 | Acquisition by a Campylobacter-like strain of aphA-1, a kanamycin resistance determinant from members of the family Enterobacteriaceae. A Campylobacter-like organism, BM2196, resistant to kanamycin and streptomycin-spectinomycin was isolated from the feces of a patient with acute enteritis. The kanamycin and streptomycin-spectinomycin resistances were not transferable to Camplylobacter sp. or to Escherichia coli, and no plasmid DNA was detected in this strain. The resistance genes were therefore tentatively assigned to a chromosomal locality. Analysis by the phosphocellulose paper-binding assay of extracts from BM2196 indicated that resistance to kanamycin and structurally related antibiotics was due to the synthesis of 3'-aminoglycoside phosphotransferase type I [APH(3')-I], an enzyme specific for gram-negative bacteria, and that resistance to streptomycin-spectinomycin was secondary to the presence of a 3",9-aminoglycoside adenylyltransferase. Homology between BM2196 and an APH(3')-I probe was detected by DNA-DNA hybridization. A 2.2-kilobase BM2196 DNA fragment conferring resistance to kanamycin was cloned in E. coli and was sequenced partially. The resistance gene appeared nearly identical to that of Tn903 from E. coli and was adjacent to IS15-delta, an insertion sequence widespread in gram-negative bacteria, thus indicating that Campylobacter species can act as a recipient for genes originating in members of the family Enterobacteriaceae. | 1987 | 2821885 |
| 1771 | 8 | 0.9992 | Occurrence of integron-associated resistance gene cassettes located on antibiotic resistance plasmids isolated from a wastewater treatment plant. The role of a municipal wastewater treatment plant as a reservoir for bacteria carrying antibiotic resistance plasmids was analysed. Altogether, ninety-seven different multiresistance plasmids were isolated and screened by PCR for the presence of class 1 integron-specific sequences. Twelve of these plasmids were identified to carry integrons. In addition, integron-specific sequences were found on plasmid-DNA preparations from bacteria residing in activated sludge and in the final effluents of the wastewater treatment plant. Sequencing and annotation of the integrons identified nineteen different gene cassette arrays, containing twenty-one different resistance gene cassettes. These cassettes carry genes encoding eight different aminoglycoside-modifying enzymes, seven dihydrofolate reductases, three beta-lactamases, two chloramphenicol resistance proteins and two small exporter proteins. Moreover, new gene cassettes and cassettes with unknown function were identified. Eleven gene cassette combinations are described for the first time. Six integron-associated gene cassette arrays are located on self-transmissible, putative broad-host-range plasmids belonging to the IncP group. Hybridisation analyses, using the integron-specific gene cassette arrays as templates and labelled plasmid-DNA preparations from bacteria of the final effluents as hybridisation probes, revealed that bacteria containing integron-specific sequences on plasmids are released into the environment. | 2003 | 19719593 |
| 5851 | 9 | 0.9992 | Arsenic resistance determinants from environmental bacteria. Arsenic resistance determinants from 42 environmental bacterial isolates (32 Gram negative) were analyzed by DNA: DNA hybridization using probes derived from Escherichia coli and Staphylococcus plasmid or chromosomal arsenic resistance (ars) genes. In colony hybridization assays, 11 and 1 Gram negative strains hybridized with the E. coli chromosome and plasmid probes, respectively. No hybridization was detected using a probe containing only the arsA (ATPase) gene from E. coli plasmid or with a Staphylococcus plasmid ars probe. From Southern hybridization tests of some of the positive strains it was concluded that homology to ars chromosomal genes occurred within chromosome regions, except in an E. coli isolate where hybridization occurred in both the chromosome and a 130-kb plasmid. Our results show that DNA sequences homologous to E. coli ars chromosomal genes are commonly present in the chromosomes of environmental arsenic-resistant Gram negative isolates. | 1998 | 10932734 |
| 4466 | 10 | 0.9992 | Antibiotic resistance in gram-negative bacteria: the role of gene cassettes and integrons. Resistance of gram-negative organisms to antibiotics such as beta-lactams, aminoglycosides, trimethoprim and chloramphenicol is caused by many different acquired genes, and a substantial proportion of these are part of small mobile elements known as gene cassettes. A gene cassette consists of the gene and a downstream sequence, known as a 59-base element (59-be), that acts as a specific recombination site. Gene cassettes can move into or out of a specific receptor site (attl site) in a companion element called an integron, and integration or excision of the cassettes is catalysed by a site-specific recombinase (Intl) that is encoded by the integron. At present count there are 40 different cassette-associated resistance genes and three distinct classes of integron, each encoding a distinct Intl integrase. The same cassettes are found in all three classes of integron, indicating that cassettes can move freely between different integrons. Integrons belonging to class I often contain a further antibiotic resistance gene, sull, conferring resistance to sulphonamides. The sull gene is found in a conserved region (3'-CS) that is not present in all members of this class. Class I integrons of the sull type are most prevalent in clinical isolates and have been found in many different organisms. Even though most of them are defective transposon derivatives, having lost at least one of the transposition genes, they are none the less translocatable and consequently found in many different locations. The transposon Tn7 is the best known representative of class 2 integrons, and Tn7 and relatives are also found in many different species. | 1998 | 16904397 |
| 3051 | 11 | 0.9992 | Nucleotide sequence of the bacterial streptothricin resistance gene sat3. The nucleotide sequence of the sat3 gene which encodes resistance of enteric bacteria to the antibiotic streptothricin is reported. A protein with a molecular mass of about 23 kDa is expressed from this gene. The sat3 gene is not obviously related to any one of the streptothricin resistance determinants identified so far among Gram-negative or Gram-positive bacteria. | 1995 | 7640311 |
| 4503 | 12 | 0.9992 | Evolution and transfer of aminoglycoside resistance genes under natural conditions. 3'-Aminoglycoside phosphotransferases [APH(3')] were chosen as a model to study the evolution and the transfer of aminoglycoside resistance genes under natural conditions. Comparison of the amino acid sequences of APH(3') enzymes from transposons Tn903 (type I) and Tn5 (type II) detected in Gram-negative bacteria, from the Gram-positive Staphylococcus and Streptococcus (type III), from the butirosin-producing Bacillus circulans (type IV) and from a neomycin-producing Streptomyces fradiae (type V) indicate that they have diverged from a common ancestor. These structural data support the hypothesis that the antibiotic-producing strains were the source of certain resistance determinants. We have shown that kanamycin resistance in Campylobacter coli BM2509 was due to the synthesis of an APH(3')-III, an enzyme not detected previously in a Gram-negative bacterium. The genes encoding APH(3')-III in Streptococcus and Campylobacter are identical. These findings constitute evidence for a recent in-vivo transfer of DNA between Gram-positive and Gram-negative bacteria. | 1986 | 3027020 |
| 5855 | 13 | 0.9992 | Plasmid-encoded resistance to arsenic compounds in Gram-negative bacteria isolated from a hospital environment in Venezuela. Resistance to arsenic compounds was examined among amikacin resistant Gram-negative bacteria isolate from a hospital environment. Arsenite resistance (Ars(r)) was found in a high proportion of isolates ( >60%) being frequently associated with resistance to tellurite (40%), and to other antimicrobial agents. Ars determinants (27%) were found to be transferable to E. coli K12 strains from which large plasmid DNA molecules were isolated and characterized by agarose gel electrophoresis. Plasmids were identified by both classical incompatibility tests, and by replicon typing using DNA specific probes. Most of the amikacin-arsenite (Ak-Ars) conjugative plasmids belong to the H incompatibility group. These results suggest that Ak-Ars resistance linked to IncH plasmids is wide spread in Gram-negative bacteria. | 1997 | 18611788 |
| 3045 | 14 | 0.9992 | Plasmid-borne sulfonamide resistance determinants studied by restriction enzyme analysis. The relationship between sulfonamide resistance genes carried on different plasmids was investigated by restriction enzyme analysis and DNA-DNA hybridization. The results showed that sulfonamide resistance mediated by different plasmids is determined by the production of at least two different types of drug-resistant dihydropteroate synthase. Plasmids pGS01, pGS02, and R22259, found in bacteria isolated from patients in Swedish hospitals, contained identical sulfonamide resistance genes, which were also identical to those of plasmids R1, R100, R6, and R388. These latter plasmids, which have been well studied in different laboratories, were originally from clinical isolates from different parts of the world. Two other clinically isolated plasmids, pGS04 and pGS05, were shown to contain sulfonamide resistance determinants of a completely different type. | 1983 | 6298179 |
| 3060 | 15 | 0.9992 | Integron mobilization unit as a source of mobility of antibiotic resistance genes. Antibiotic resistance genes are spread mostly through plasmids, integrons (as a form of gene cassettes), and transposons in gram-negative bacteria. We describe here a novel genetic structure, named the integron mobilization unit (IMU), that has characteristics similar to those of miniature inverted transposable elements (MITEs). Two IMUs (288 bp each) were identified from a carbapenem-resistant Enterobacter cloacae isolate that formed a composite structure encompassing a defective class 1 integron containing the carbapenem resistance gene bla(GES-5). This beta-lactamase gene was located on a 7-kb IncQ-type plasmid named pCHE-A, which was sequenced completely. The plasmid pCHE-A was not self conjugative but was mobilizable, and it was successfully transferred from E. cloacae to Pseudomonas aeruginosa. The in silico analysis of the extremities of the IMU elements identified similarities with those of insertion sequence ISSod9 from Shewanella oneidensis MR-1. The mobilization of the IMU composite structure was accomplished by using the transposase activity of ISSod9 that was provided in trans. This is the first identification of MITE-type structures as a source of gene mobilization, implicating here a clinically relevant antibiotic resistance gene. | 2009 | 19332679 |
| 4467 | 16 | 0.9992 | PCR mapping of integrons reveals several novel combinations of resistance genes. The integron is a new type of mobile element which has evolved by a site-specific recombinational mechanism. Integrons consist of two conserved segments of DNA separated by a variable region containing one or more genes integrated as cassettes. Oligonucleotide probes specific for the conserved segments have revealed that integrons are widespread in recently isolated clinical bacteria. Also, by using oligonucleotide probes for several antibiotic resistance genes, we have found novel combinations of resistance genes in these strains. By using PCR, we have determined the content and order of the resistance genes inserted between the conserved segments in the integrons of these clinical isolates. PCR mapping of integrons can be a useful epidemiological tool to study the evolution of multiresistance plasmids and transposons and dissemination of antibiotic resistance genes. | 1995 | 7695304 |
| 379 | 17 | 0.9992 | Broad host range DNA cloning system for gram-negative bacteria: construction of a gene bank of Rhizobium meliloti. A broad host range cloning vehicle that can be mobilized at high frequency into Gram-negative bacteria has been constructed from the naturally occurring antibiotic resistance plasmid RK2. The vehicle is 20 kilobase pairs in size, encodes tetracycline resistance, and contains two single restriction enzyme sites suitable for cloning. Mobilization is effected by a helper plasmid consisting of the RK2 transfer genes linked to a ColE1 replicon. By use of this plasmid vehicle, a gene bank of the DNA from a wild-type strain of Rhizobium meliloti has been constructed and established in Escherichia coli. One of the hybrid plasmids in the bank contains a DNA insert of approximately 26 kilobase pairs which has homology to the nitrogenase structural gene region of Klebsiella pneumoniae. | 1980 | 7012838 |
| 4528 | 18 | 0.9992 | Study on the excision and integration mediated by class 1 integron in Streptococcus pneumoniae. As a novel antibiotic resistance mobile element, integron was recognized as a primary source of antibiotic genes among Gram-positive organisms for its excision and integration of exogenous genes. In this study, Streptococcus pneumoniae was subjected to investigate the excision and integration of class 1 integron with eight different plasmids. As the results indicated, excision in both att site and gene cassettes were successfully observed, which was further confirmed by integration assays and PCR amplification. The observation of class 1 integron mediated excision and integration of various exogenous antibiotics resistance genes may raise the attention of integrons as novel antibiotic resistance determinant in Gram-positive bacteria, especially in Streptococcus. | 2017 | 28923604 |
| 5854 | 19 | 0.9991 | Discovery of a gene conferring multiple-aminoglycoside resistance in Escherichia coli. Bovine-origin Escherichia coli isolates were tested for resistance phenotypes using a disk diffusion assay and for resistance genotypes using a DNA microarray. An isolate with gentamicin and amikacin resistance but with no corresponding genes detected yielded a 1,056-bp DNA sequence with the closest homologues for its inferred protein sequence among a family of 16S rRNA methyltransferase enzymes. These enzymes confer high-level aminoglycoside resistance and have only recently been described in Gram-negative bacteria. | 2010 | 20368404 |