# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 3011 | 0 | 0.9984 | A novel cfr-carrying Tn7 transposon derivative characterized in Morganella morganii of swine origin in China. OBJECTIVES: To characterize the presence and genetic environment of the multiresistance gene cfr in bacterial isolates from a swine farm. METHODS: A total of 97 bacterial isolates, recovered from 32 faecal swabs obtained on one farm, were tested for the presence of the cfr gene by PCR. Species identification of the one cfr-positive strain was conducted using the BD PhoenixTM 100 Automated Microbiology System. Susceptibility testing was carried out by broth microdilution. The genetic environment of the cfr gene was analysed by WGS. RESULTS: The Morganella morganii isolate BCMM24 was the only cfr-positive strain. The cfr gene, as well as 15 other resistance genes, is located on a novel 111238 bp transposon derived from Tn7, designated as Tn6451, which comprises various genetic materials including a novel class 1 integron with five gene cassettes. The cfr-containing region consists of a novel genetic structure IS26-cfr-ΔTn554 tnpB-ΔTn3 family tnpA-IS26, differing from previous reports. Two-step PCR results show that the structure can be looped out and that Tn6451 cannot be excised from the chromosome. CONCLUSIONS: To the best of our knowledge, we report the cfr gene in M. morganii for the first time. The cfr gene and 15 other resistance genes are located on a novel Tn7 transposon derivative, suggesting that the Tn7 transposon may act as a reservoir for various antimicrobial resistance genes and more Tn7 derivatives carrying multiple resistance genes are likely to be discovered in Gram-negative bacteria of both animal and human origin. | 2019 | 30508103 |
| 5871 | 1 | 0.9982 | Plasmid-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. | 2006 | 16670108 |
| 3012 | 2 | 0.9981 | 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 |
| 3010 | 3 | 0.9980 | Identification 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. | 2021 | 33486327 |
| 5872 | 4 | 0.9979 | Characterization of the plasmids harbouring the florfenicol resistance gene floR in Glaesserella parasuis and Actinobacillus indolicus. OBJECTIVES: The aim of this study was to characterize the floR-carrying plasmids originating from Glaesserella parasuis and Actinobacillus indolicus isolated from pigs with respiratory disease in China. METHODS: A total of 125 G. parasuis and 28 A. indolicus strains collected between 2009 and 2022 were screened for florfenicol resistance. Characterization of floR-positive isolates and plasmids were determined by antimicrobial susceptibility testing, serotyping, multilocus sequence typing (MLST), conjugation and transformation assays, whole-genome sequencing (WGS), and phylogenetic analysis. RESULTS: One A. indolicus and six G. parasuis were identified as positive for floR. The six G. parasuis were assigned to four different serovars, including serovars 6, 7, 9, and unknown. In addition to strain XP11, six floR genes were located on plasmids. The six floR-bearing plasmids could be transformed into Pasteurella multocida and divided into two different types, including ∼5000 bp and ∼6000 bp plasmids. The ∼5000 bp plasmids consisting of rep, lysR, mobB, and floR genes, exhibited high similarity among Pasteurellaceae bacteria. Furthermore, the ∼6000 bp plasmids, consisting of rep, lysR, mobC, mobA/L, and floR genes, showed high similarity between G. parasuis and Actinobacillus Spp. Notably, WGS results showed that the floR modules of the two types of plasmids could be transferred and integrated into the diverse Pasteurellaceae- origined plasmids. CONCLUSION: This study firstly reported the characterization of floR-carrying plasmids from A. indolicus and a non-virulent serovar of G. parasuis in pigs in China and elucidated the transmission mechanism of the floR resistance gene among the Pasteurellaceae family. | 2023 | 37726088 |
| 2007 | 5 | 0.9978 | Novel ISCR1-linked resistance genes found in multidrug-resistant Gram-negative bacteria in southern China. Non-duplicate multidrug-resistant (MDR) Gram-negative bacteria (n=1329) isolated from southern China between January 2008 and December 2009 were investigated for the presence of ISCR1 as well as characterisation of ISCR1-linked resistance genes. Of 433 ISCR1-positive strains, 151 appeared to carry ISCR1-linked resistance genes. Seven different ISCR1-linked resistance gene arrays were identified by restriction fragment length polymorphism (RFLP) and DNA sequencing analysis. Many of these arrays are reported in some species for the first time. A total of 12 genes, including a novel ABC transporter (GenBank accession no. GU944725), qnrA1, qnrB2, qnrB6, bla(DHA-1), ampR, bla(CTX-M-9), bla(PER-1), insB, sapA-like peptide transport periplasmic protein, putative glutathione S-transferase and short-chain dehydrogenase/reductase, were detected. This study was the first to employ PCR-RFLP using HinfI and RsaI to analyse ISCR1-linked genes. ISCR1 was widely disseminated among MDR Gram-negative bacteria and was in close association with quinolone resistance and β-lactamase genes (class A and class C) in southern China. | 2012 | 22890194 |
| 5867 | 6 | 0.9978 | Molecular analysis of florfenicol-resistant Pasteurella multocida isolates in Germany. OBJECTIVES: Three florfenicol-resistant Pasteurella multocida isolates from Germany, two from swine and one from a calf, were investigated for the genetics and transferability of florfenicol resistance. METHODS: The isolates were investigated for susceptibility to antimicrobial agents and plasmid content. Florfenicol resistance plasmids carrying the gene floR were identified by transformation and PCR. Plasmids were mapped, and a novel plasmid type was sequenced completely. PFGE served to determine the clonality of the isolates. RESULTS: In one porcine and the bovine P. multocida isolate, florfenicol resistance was associated with the plasmid pCCK381 previously described in a bovine P. multocida isolate from the UK. The remaining porcine isolate harboured a new type of floR-carrying plasmid, the 10 226 bp plasmid pCCK1900. Complete sequence analysis identified an RSF1010-like plasmid backbone with the mobilization genes mobA, mobB and mobC, the plasmid replication genes repA, repB and repC, the sulphonamide resistance gene sul2 and the streptomycin resistance genes strA and strB. The floR gene area was integrated into a region downstream of strB, which exhibited homology to the floR flanking regions found in various bacteria. PFGE revealed that the floR-carrying P. multocida strains from Germany were unrelated and also different from the UK strain. CONCLUSIONS: After the UK and France, floR-mediated florfenicol resistance has now also been identified in target bacteria from Germany. PFGE data and the analysis of plasmids strongly suggested that the spread of florfenicol resistance is due to the horizontal transfer of plasmids rather than the clonal dissemination of a resistant P. multocida isolate. | 2008 | 18786941 |
| 3009 | 7 | 0.9978 | 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 |
| 5406 | 8 | 0.9978 | Detection of poxtA- and optrA-carrying E. faecium isolates in air samples of a Spanish swine farm. OBJECTIVE: Two linezolid-resistant Enterococcus faecium isolates, C10004 and C10009, were recovered from air samples of a Spanish swine farm and comprehensively characterized. METHODS: Detection of linezolid resistance mechanisms (mutations and acquisition of resistance genes) was performed by PCR/sequencing. Isolates were characterized by multilocus sequence typing (MLST), antimicrobial susceptibility testing, detection of antimicrobial resistance and virulence genes, and analysis of the genetic environment of the linezolid resistance genes. The characterization of isolate C10009 was performed by Whole-Genome-Sequencing and of isolate C10004 by PCR and amplicon sequencing, where applicable. Conjugation experiments to assess the transferability of the optrA and poxtA genes implicated in linezolid resistance were performed. RESULTS: The linezolid-resistant E. faecium isolates C10004 and C10009, assigned to ST128 and ST437, respectively, harbored the optrA and poxtA genes. Neither mutations in the 23S rRNA nor in the genes for the ribosomal proteins L3, L4 and L22 were detected. C10004 and C10009 carried fourteen and thirteen antimicrobial resistance genes, respectively. The sequence alignment indicated that the genetic environment of the poxtA gene was identical in both isolates, with a downstream-located fexB gene. The poxtA gene was transferred by conjugation together with the fexB gene, and also with tet(M) and tet(L) in the case of isolate C10004. The optrA gene could not be transferred. CONCLUSIONS: This is the first report of the poxtA gene in Spain. The presence of poxtA- and optrA-carrying E. faecium isolates in air samples represents a public health concern, indicating an involvement of swine farms in the spread of linezolid-resistant bacteria. | 2020 | 31884049 |
| 1754 | 9 | 0.9978 | Transposons Carrying the aacC2e Aminoglycoside and bla(TEM) Beta-Lactam Resistance Genes in Acinetobacter. This study examines the genetic contexts and evolutionary steps responsible for the formation of the widely spread transposon Tn6925 carrying bla(TEM) and aacC2e, which confers resistance to beta-lactam and aminoglycoside antibiotics in Gram-negative bacteria. The bla(TEM-1) and aacC2e genes were found in several transposons. They were first observed within an IS26 bounded 3.7 kb transposon (Tn6925) on several Acinetobacter baumannii plasmids located within a 4.7 kb dif module. Truncated and expanded variations of Tn6925 were found across other A. baumannii plasmids, as well as in other Gram-negative bacteria (including Vibrio cholerae). Moreover, bla(TEM-1) and aacC2e were in much larger resistance-heavy transposons including the ISAba1-bounded 24.6 kb (here called Tn6927), found in an A. baumannii chromosome. A novel ISKpn12-bounded transposon was also observed to contain bla(TEM) and aacC2e which was found interrupting Tn5393 along with an IS26 pseudo-compound transposon to form a 24.9 kb resistance island in an Acinetobacter pittii plasmid. Multiple mobile genetic elements are involved in the formation of transposon structures that circulate bla(TEM) and aacC2e. Among these, IS26 and ISAba1 appear to have played a major role in the formation and spread of these elements in the Acinetobacter species. | 2024 | 38593463 |
| 5866 | 10 | 0.9978 | tet(L)-mediated tetracycline resistance in bovine Mannheimia and Pasteurella isolates. OBJECTIVES: Tetracycline-resistant Mannheimia and Pasteurella isolates, which were negative for the tetracycline resistance genes (tet) commonly detected among these bacteria, were investigated for other tet genes present and their location. METHODS: Mannheimia and Pasteurella isolates were investigated for their MICs of tetracycline and their plasmid content. Identification of tet genes was achieved by PCR. Plasmids mediating tetracycline resistance were identified by transformation and hybridization experiments. Plasmid pCCK3259 from Mannheimia haemolytica was sequenced completely and analysed for its structure and organization. RESULTS: All tetracycline-resistant isolates carried the gene tet(L) either on plasmids or on the chromosome. Two M. haemolytica isolates and one Mannheimia glucosida isolate harboured a common 5.3 kb tet(L) plasmid, designated pCCK3259. This plasmid was similar to the tet(B)-carrying tetracycline resistance plasmid pHS-Tet from Haemophilus parasuis and the streptomycin/spectinomycin resistance plasmid pCCK647 from Pasteurella multocida in the parts coding for mobilization functions. The tet(L) gene was closely related to that of the Geobacillus stearothermophilus plasmid pTB19. However, the translational attenuator responsible for the tetracycline-inducible expression of tet(L) was missing in plasmid pCCK3259. A recombination site was identified downstream of tet(L), which might explain the integration of the tet(L) gene region into a basic pCCK3259 replicon. CONCLUSION: A tet(L) gene was shown for the first time to be responsible for tetracycline resistance in Mannheimia and Pasteurella isolates. This report demonstrates a lateral transfer of a tetracycline efflux gene in Gram-negative bovine respiratory tract pathogens, probably originating from Gram-positive bacteria. | 2005 | 15972309 |
| 1779 | 11 | 0.9978 | New structures simultaneously harboring class 1 integron and ISCR1-linked resistance genes in multidrug-resistant Gram-negative bacteria. BACKGROUND: The connection structure of class 1 integron and insertion sequence common region 1 (ISCR1) is called "complex class 1 integrons" or "complex sul1-type integrons", which is also known to be associated with many resistance genes. This structure is a powerful gene-capturing tool kit that can mobilize antibiotic resistance genes. In order to look for and study the structure among clinical multidrug-resistant (MDR) Gram-negative isolates, 63 isolates simultaneously harbored class 1 integron and ISCR1-linked resistance genes were isolated from 2309 clinical non-redundant MDR Gram-negative isolates in Nanfang Hospital in 2008-2013. The connecting regions between the class 1 integrons and ISCR1 were examined using PCR and DNA sequencing to determine the structures in these isolates. RESULT: The two elements (the variable regions of the class 1 integron structures and the ISCR1-linked resistance genes) are connected in series among 63 isolates according to long-extension PCR and DNA sequencing. According to the kinds and permutations of resistance genes in the structure, 12 distinct types were identified, including 8 types that have never been described in any species. Several types of these structures are similar with the structures of other reports, but not entirely same. CONCLUSION: This study is the first to determine the structure simultaneously harboring class 1 integron and ISCR1-linked resistance genes by detecting the region connecting class 1 integrons and ISCR1 in a large number of MDR bacteria. These structures carrying various resistance genes were closely associated with multidrug resistance bacteria in Southern China. | 2016 | 27103443 |
| 1777 | 12 | 0.9977 | Inter-phylum circulation of a beta-lactamase-encoding gene: a rare but observable event. Beta-lactamase-mediated degradation of beta-lactams is the most common mechanism of beta-lactam resistance in Gram-negative bacteria. Beta-lactamase-encoding genes can be transferred between closely related bacteria, but spontaneous inter-phylum transfers (between distantly related bacteria) have never been reported. Here, we describe an extended-spectrum beta-lactamase (ESBL)-encoding gene (bla(MUN-1)) shared between the Pseudomonadota and Bacteroidota phyla. An Escherichia coli strain was isolated from a patient in Münster (Germany). Its genome was sequenced. The ESBL-encoding gene (named bla(MUN-1)) was cloned, and the corresponding enzyme was characterized. The distribution of the gene among bacteria was investigated using the RefSeq Genomes database. The frequency and relative abundance of its closest homolog in the global microbial gene catalog (GMGC) were analyzed. The E. coli strain exhibited two distinct morphotypes. Each morphotype possessed two chromosomal copies of the bla(MUN-1) gene, with one morphotype having two additional copies located on a phage-plasmid p0111. Each copy was located within a 7.6-kb genomic island associated with mobility. bla(MUN-1) encoded for an extended-spectrum Ambler subclass A2 beta-lactamase with 43.0% amino acid identity to TLA-1. bla(MUN-1) was found in species among the Bacteroidales order and in Sutterella wadsworthensis (Pseudomonadota). Its closest homolog in GMGC was detected frequently in human fecal samples. This is, to our knowledge, the first reported instance of inter-phylum transfer of an ESBL-encoding gene, between the Bacteroidota and Pseudomonadota phyla. Although the gene was frequently detected in the human gut, inter-phylum transfer was rare, indicating that inter-phylum barriers are effective in impeding the spread of ESBL-encoding genes, but not entirely impenetrable. | 2024 | 38441061 |
| 5852 | 13 | 0.9977 | A novel transposon, Tn6009, composed of a Tn916 element linked with a Staphylococcus aureus mer operon. OBJECTIVES: The aim of this study was to characterize a novel conjugative transposon Tn6009 composed of a Tn916 linked to a Staphylococcus aureus mer operon in representative Gram-positive and Gram-negative bacteria isolated in Nigeria and Portugal. METHODS: Eighty-three Gram-positive and 34 Gram-negative bacteria were screened for the presence of the Tn6009 using DNA-DNA hybridization, PCR, hybridization of PCR products, sequencing and mating experiments by established procedures. RESULTS: Forty-three oral and 23 urine Gram-negative and Gram-positive isolates carried the Tn6009. Sequencing was performed to verify the direct linkage between the mer resistance genes and the tet(M) gene. A Nigerian Klebsiella pneumoniae, isolated from a urinary tract infection patient, and one commensal isolate from each of the other Tn6009-positive genera, Serratia liquefaciens, Pseudomonas sp., Enterococcus sp. and Streptococcus sp. isolated from the oral and urine samples of healthy Portuguese children, were able to act as donors and conjugally transfer the Tn6009 to the Enterococcus faecalis JH2-2 recipient, resulting in tetracycline- and mercury-resistant E. faecalis transconjugants. CONCLUSIONS: This study reports a novel non-composite conjugative transposon Tn6009 containing a Tn916 element linked to an S. aureus mer operon carrying genes coding for inorganic mercury resistance (merA), an organic mercury resistance (merB), a regulatory protein (merR) and a mercury transporter (merT). This transposon was identified in 66 isolates from two Gram-positive and three Gram-negative genera and is the first transposon in the Tn916 family to carry the Gram-positive mer genes directly linked to the tet(M) gene. | 2008 | 18583328 |
| 5854 | 14 | 0.9977 | 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 |
| 5853 | 15 | 0.9977 | Identification of the tet(B) resistance gene in Streptococcus suis. The tetracycline resistance gene, tet(B), has been described previously in gram negative bacteria. In this study tet(B) was detected in plasmid extracts from 17/111 (15%) Streptococcus suis isolates from diseased pigs, representing the first report of this resistance gene in gram positive bacteria. | 2011 | 20696603 |
| 3050 | 16 | 0.9977 | The type VII dihydrofolate reductase: a novel plasmid-encoded trimethoprim-resistant enzyme from gram-negative bacteria isolated in Britain. Plasmid pUN835 was identified in an Escherichia coli strain isolated from an outbreak of porcine diarrhoea on a farm near Nottingham, UK. The trimethoprim resistance gene did not hybridize with any of the gene probes derived from known plasmid-encoded trimethoprim resistance genes. The trimethoprim resistance gene of pUN835 was shown to encode the production of a dihydrofolate reductase which confers high-level resistance on its host. This enzyme was smaller than most plasmid-encoded dihydrofolate reductases (molecular mass = 11,500) and was labile to heat. It had relatively low affinity for the substrate dihydrofolate (Km = 20 microM) and it was resistant to competitive inhibition by trimethoprim (Ki = 7.0 microM). We classify this novel enzyme as type VII. | 1989 | 2676936 |
| 5847 | 17 | 0.9977 | Distribution and molecular characterization of tetracycline resistance in Laribacter hongkongensis. OBJECTIVES: Laribacter hongkongensis is a newly discovered bacterium associated with gastroenteritis and found in freshwater fish. Although isolates resistant to tetracycline have been described, their resistance mechanisms have not been studied. PATIENTS AND METHODS: We describe the distribution and molecular characterization of tetracycline resistance in 48 L. hongkongensis isolates from humans and fish. RESULTS: Three human isolates and one fish isolate were resistant to tetracycline (MIC 128 mg/L) and doxycycline (MIC 8-16 mg/L) and had reduced susceptibility to minocycline (MIC 1-4 mg/L). A 3566 bp gene cluster, which contains tetR and tetA, was cloned from one of the tetracycline-resistant strains, HLHK5. While the flanking regions and 3' end of the tetA of HLHK5 were identical to the corresponding regions of a tetC island in Chlamydia suis, the tetA gene was almost identical to that of transposon Tn1721 and plasmids of gram-negative bacteria, suggesting that the tetA/tetR of HLHK5 may have arisen from illegitimate recombination. PCR and DNA sequencing showed the presence of tetA in the other three tetracycline-resistant L. hongkongensis strains. Sequencing and characterization of a 15,665 bp plasmid, pHLHK22, from strain HLHK22 revealed the presence of a similar tetA/tetR gene cluster. This novel plasmid also confers tetracycline resistance when transformed to Escherichia coli and other L. hongkongensis isolates. CONCLUSIONS: Horizontal transfer of genes, especially through Tn1721 and related plasmids, is likely an important mechanism for acquisition and dissemination of tetracycline resistance in L. hongkongensis. The present study is the first report on identification of tetA genes in bacteria of the Neisseriaceae family. | 2008 | 18227089 |
| 5197 | 18 | 0.9977 | Genome analysis of NDM-1 producing Morganella morganii clinical isolate. OBJECTIVE: To analyze the resistome and virulence genes of Morganella morganii F675, a multidrug-resistant clinical isolate using whole genome sequencing (WGS). METHODS: M. morganii F675 was isolated from a patient from Jerusalem, Israel. WGS was performed using both 454 and SOLiD sequencing technologies. Analyses of the bacterial resistome and other virulence genes were performed in addition to comparison with other available M. morganii genomes. RESULTS: The assembled sequence had a genome size of 4,127,528 bp with G+C content of 51%. The resistome consisted of 13 antibiotic resistance genes including blaNDM-1 located in a plasmid likely acquired from Acinetobacter spp. Moreover, we characterized for the first time the whole lipid A biosynthesis pathway in this species along with the O-antigen gene cluster, the urease gene cluster and several other virulence genes. CONCLUSION: The WGS analysis of this pathogen further provides insight into its pathogenicity and resistance to antibiotics. | 2014 | 25081858 |
| 5490 | 19 | 0.9976 | Molecular and genome characterization of colistin-resistant Escherichia coli isolates from wild sea lions (Zalophus californianus). Using molecular and whole-genome sequencing tools, we investigated colistin-resistant Escherichia coli isolates from wild sea lions. Two unrelated E. coli colistin-resistant isolates, ST8259 and ST4218, were identified, both belonging to the B2 phylogroup and different serotypes. Polymorphisms in PmrA, PmrB, and PhoQ proteins were identified, and the role of PmrB and PhoQ in contributing to colistin resistance was determined by complementation assays. However, the mutations characterized in the present study are not involved in colistin resistance, which have been described in E. coli isolates from clinical settings. Therefore, the acquired mutations in pmrB and phoQ genes in resistance to colistin in bacteria related to marine environment animals are different. This work contributes to the surveillance and characterization of colistin resistance in Escherichia coli obtained from animals from aquatic environments. | 2020 | 32897511 |