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584700.8709Distribution 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.200818227089
303610.8691Complete 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
522120.8690Molecular cloning of the DNA gyrase genes from Methylovorus sp. strain SS1 and the mechanism of intrinsic quinolone resistance in methylotrophic bacteria. The genes encoding the DNA gyrase A (GyrA) and B subunits (GyrB) of Methylovorus sp. strain SS1 were cloned and sequenced. gyrA and gyrB coded for proteins of 846 and 799 amino acids with calculated molecular weights of 94,328 and 88,714, respectively, and complemented Escherichia coli gyrA and gyrB temperature sensitive (ts) mutants. To analyze the role of type II topoisomerases in the intrinsic quinolone resistance of methylotrophic bacteria, the sequences of the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase and the C subunit (ParC) of topoisomerase IV (Topo IV) of Methylovorus sp. strain SS1, Methylobacterium extorquens AM1 NCIB 9133, Methylobacillus sp, strain SK1 DSM 8269, and Methylophilus methylotrophus NCIB 10515 were determined. The deduced amino acid sequences of the QRDRs of the ParCs in the four methylotrophic bacteria were identical to that of E. coli ParC. The sequences of the QRDR in GyrA were also identical to those in E. coli GyrA except for the amino acids at positions 83, 87, or 95. The Ser83 to Thr substitution in Methylovorus sp. strain SS1, and the Ser83 to Leu and Asp87 to Asn substitutions in the three other methylotrophs, agreed well with the minimal inhibitory concentrations of quinolones in the four bacteria, suggesting that these residues play a role in the intrinsic susceptibility of methylotrophic bacteria to quinolones.200516404155
81930.8690Trimethoprim resistance transposon Tn4003 from Staphylococcus aureus encodes genes for a dihydrofolate reductase and thymidylate synthetase flanked by three copies of IS257. Trimethoprim resistance mediated by the Staphylococcus aureus multi-resistance plasmid pSK1 is encoded by a structure with characteristics of a composite transposon which we have designated Tn4003. Nucleotide sequence analysis of Tn4003 revealed it to be 4717 bp in length and to contain three copies of the insertion element IS257 (789-790 bp), the outside two of which are flanked by directly repeated 8-bp target sequences. IS257 has imperfect terminal inverted repeats of 27-28 bp and encodes for a putative transposase with two potential alpha-helix-turn-alpha-helix DNA recognition motifs. IS257 shares sequence similarities with members of the IS15 family of insertion sequences from Gram-negative bacteria and with ISS1 from Streptococcus lactis. The central region of the transposon contains the dfrA gene that specifies the S1 dihydrofolate reductase (DHFR) responsible for trimethoprim resistance. The S1 enzyme shows sequence homology with type I and V trimethoprim-resistant DHFRs from Gram-negative bacteria and with chromosomally encoded DHFRs from Gram-positive and Gram-negative bacteria. 5' to dfrA is a thymidylate synthetase gene, designated thyE.19892548057
153540.8682Complete Genome Sequencing of Acinetobacter baumannii AC1633 and Acinetobacter nosocomialis AC1530 Unveils a Large Multidrug-Resistant Plasmid Encoding the NDM-1 and OXA-58 Carbapenemases. Carbapenem-resistant Acinetobacter spp. are considered priority drug-resistant human-pathogenic bacteria. The genomes of two carbapenem-resistant Acinetobacter spp. clinical isolates obtained from the same tertiary hospital in Terengganu, Malaysia, namely, A. baumannii AC1633 and A. nosocomialis AC1530, were sequenced. Both isolates were found to harbor the carbapenemase genes bla(NDM-1) and bla(OXA-58) in a large (ca. 170 kb) plasmid designated pAC1633-1 and pAC1530, respectively, that also encodes genes that confer resistance to aminoglycosides, sulfonamides, and macrolides. The two plasmids were almost identical except for the insertion of ISAba11 and an IS4 family element in pAC1633-1, and ISAba11 along with relBE toxin-antitoxin genes flanked by inversely orientated pdif (XerC/XerD) recombination sites in pAC1530. The bla(NDM-1) gene was encoded in a Tn125 composite transposon structure flanked by ISAba125, whereas bla(OXA-58) was flanked by ISAba11 and ISAba3 downstream and a partial ISAba3 element upstream within a pdif module. The presence of conjugative genes in plasmids pAC1633-1/pAC1530 and their discovery in two distinct species of Acinetobacter from the same hospital are suggestive of conjugative transfer, but mating experiments failed to demonstrate transmissibility under standard laboratory conditions. Comparative sequence analysis strongly inferred that pAC1633-1/pAC1530 was derived from two separate plasmids in an IS1006-mediated recombination or transposition event. A. baumannii AC1633 also harbored three other plasmids designated pAC1633-2, pAC1633-3, and pAC1633-4. Both pAC1633-3 and pAC1633-4 are cryptic plasmids, whereas pAC1633-2 is a 12,651-bp plasmid of the GR8/GR23 Rep3-superfamily group that encodes the tetA(39) tetracycline resistance determinant in a pdif module.IMPORTANCE Bacteria of the genus Acinetobacter are important hospital-acquired pathogens, with carbapenem-resistant A. baumannii listed by the World Health Organization as the one of the top priority pathogens. Whole-genome sequencing of carbapenem-resistant A. baumannii AC1633 and A. nosocomialis AC1530, which were isolated from the main tertiary hospital in Terengganu, Malaysia, led to the discovery of a large, ca. 170-kb plasmid that harbored genes encoding the New Delhi metallo-β-lactamase-1 (NDM-1) and OXA-58 carbapenemases alongside genes that conferred resistance to aminoglycosides, macrolides, and sulfonamides. The plasmid was a patchwork of multiple mobile genetic elements and comparative sequence analysis indicated that it may have been derived from two separate plasmids through an IS1006-mediated recombination or transposition event. The presence of such a potentially transmissible plasmid encoding resistance to multiple antimicrobials warrants vigilance, as its spread to susceptible strains would lead to increasing incidences of antimicrobial resistance.202133504662
149250.8681Characterization of the tet(M)-bearing transposon Tn7125 of Escherichia coli strain A13 isolated from an intensive pig farm located in Henan province, China. BACKGROUND: Transposons carrying tet(M) in Gram-positive bacteria have been reported extensively, while there is a paucity of data on the transmission characteristics of tet(M) in Gram-negative bacteria. Therefore, the aim of this study was to investigate the genetic characteristics of the tet(M)-bearing transposon Tn7125, and to clarify the transmission mechanism of the plasmids pTA13-1 and pTA13-3 in Escherichia coli strain A13. METHODS: Plasmids from strain A13 and a corresponding transconjugant were determined by whole genome sequencing and analyzed using bioinformatics tools. The plasmids pTA13-1 and pTA13-3 of the transconjugant TA13 were characterized by S1-pulse-field gel electrophoresis, Southern hybridization, stability experiments, and direct competition assays. RESULTS: The conjugated IncF2:A6:B20 plasmid pTA13-1 co-transferred with the 41-kb plasmid pTA13-3, which carried no resistance genes; plasmid pTA13-2, which harbored the replication initiator PO111; and the IncX4 plasmid pTA13-4, which harbored the antibiotic resistance gene mcr-1. The novel IS26-bracked composite transposon Tn7125 was located on plasmid pTA13-1, which mainly consists of three resistance modules: IS26-ctp-lp-tet(M)-hp-IS406tnp, qac-aadA1-cmlA1-aadA2-DUF1010-dfrA12, and ∆ISVSa3-VirD-floR-LysR-ISVSa3. The plasmid pTA13-1 was highly stable in E. coli strain J53 with no fitness cost to the host or disadvantage in growth competition. CONCLUSION: Evolution of co-integrated transposons, such as Tn7125, may convey antibiotic resistance to a wide spectrum of hosts via the plasmids pTA13-1 and pTA13-3, which acts as an adaptable and mobile multidrug resistance reservoir to accelerate dissemination of other genes by co-selection, thereby posing a potentially serious barrier to clinical treatment regimens.202540639501
82060.8679Nucleotide sequence analysis of a transposon (Tn5393) carrying streptomycin resistance genes in Erwinia amylovora and other gram-negative bacteria. A class II Tn3-type transposable element, designated Tn5393 and located on plasmid pEa34 from streptomycin-resistant strain CA11 of Erwinia amylovora, was identified by its ability to move from pEa34 to different sites in plasmids pGEM3Zf(+) and pUCD800. Nucleotide sequence analysis reveals that Tn5393 consists of 6,705 bp with 81-bp terminal inverted repeats and generates 5-bp duplications of the target DNA following insertion. Tn5393 contains open reading frames that encode a putative transposase (tnpA) and resolvase (tnpR) of 961 and 181 amino acids, respectively. The two open reading frames are separated by a putative recombination site (res) consisting of 194 bp. Two streptomycin resistance genes, strA and strB, were identified on the basis of their DNA sequence homology to streptomycin resistance genes in plasmid RSF1010. StrA is separated from tnpR by a 1.2-kb insertion element designated IS1133. The tnpA-res-tnpR region of Tn5393 was detected in Pseudomonas syringae pv. papulans Psp36 and in many other gram-negative bacteria harboring strA and strB. Except for some strains of Erwinia herbicola, these other gram-negative bacteria lacked insertion sequence IS1133. The prevalence of strA and strB could be accounted for by transposition of Tn5393 to conjugative plasmids that are then disseminated widely among gram-negative bacteria.19938380801
175270.8677Genetic Characterization of a Linezolid- and Penicillin-Resistant Enterococcus hirae Isolate Co-Harboring poxtA and pbp5fm. Linezolid and penicillin are critical for treating multidrug resistant (MDR) Gram-positive infections, but the emergence of resistance to both seriously threatens public health. Here, we first report the cocarrying poxtA (oxazolidinone resistance) and pbp5fm (β-lactam resistance) genes by the plasmid in a strain of Enterococcus hirae HDC14-2 derived from porcine. The isolate also exhibits MDR phenotypes to phenicols, oxazolidinones, tetracyclines, β-lactams, aminoglycosides, macrolides, and lincosamides. Whole-genome sequencing (WGS) revealed these resistance genes, along with tet(L), tet(M), catA, erm(B), aac(6)-aph(2"), aadE, spw, lsa(E), lnu(B), sat4, and aphA3, were clustered in a novel MDR region flanked by IS1216 elements on plasmid pHDC14-2.133K. This IS1216-bounded MDR region formed translocatable units (TUs), including an IS1216-poxtA TU that was also identified on a secondary plasmid, pHDC14-2.27K. Functional assays demonstrated the excisability and mobility of these TUs, indicating its potential ability integration into other plasmids or chromosomes. Critically, electrotransformation confirmed the transfer of pHDC14-2.27K (poxtA-carrying) to Enterococcus faecalis JH2-2, with retained TU activity and minimal fitness cost. This study provides the evidence of colocalized poxtA and pbp5fm on plasmids in enterococci, highlighting their role in disseminating pan-resistance among bacteria. Although E. hirae is not an important pathogenic bacterium to humans and animals, but its potential risk to horizontally spread of these resistance genes important in medicine still cannot be ignored.202540692874
587580.8671Detection of the staphylococcal multiresistance gene cfr in Macrococcus caseolyticus and Jeotgalicoccus pinnipedialis. OBJECTIVES: To investigate the presence and the genetic environment of the multiresistance gene cfr in Jeotgalicoccus pinnipedialis and Macrococcus caseolyticus from pigs. METHODS: A total of 391 bacterial isolates with florfenicol MICs ≥16 mg/L were obtained from nasal swabs of 557 individual pigs; of these, 75 Gram-positive isolates other than staphylococci and enterococci were screened by PCR for the presence of known florfenicol resistance genes. Species assignments of the cfr-carrying isolates were based on the results of biochemical profiling and 16S rDNA sequencing. The locations of the cfr gene were determined by Southern blotting. Regions flanking each cfr gene were sequenced by a modified random primer walking strategy, and the transferability of cfr was assessed by electrotransformation. RESULTS: Two M. caseolyticus isolates and one J. pinnipedialis isolate were cfr positive. The cfr gene was located either on a 7057 bp plasmid, pSS-03, which was widely distributed among staphylococci of pig origin, or on the ∼53 kb plasmid pJP1. The region of pJP1 that included the cfr gene and the adjacent IS21-558, showed 99.7% identity to the corresponding region of plasmid pSCFS3. In addition, the genes aadD + aacA-aphD, ble and erm(C), coding for aminoglycoside, bleomycin and macrolide-lincosamide-streptogramin B resistance, respectively, were also identified on plasmid pJP1. CONCLUSIONS: This study showed that plasmids carrying the multidrug resistance gene cfr are present in two new genera of commensal and environmental bacteria, Macrococcus and Jeotgalicoccus. This observation underlines the role of commensal and environmental flora in the dissemination of clinically important resistance genes, such as cfr.201222577104
301190.8669A 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.201930508103
827100.8668Characterization of a ST137 multidrug-resistant Campylobacter jejuni strain with a tet(O)-positive genomic island from a bloodstream infection patient. Campylobacter jejuni (C. jejuni) is a major cause of gastroenteritis and rarely cause bloodstream infection. Herein, we characterized a multidrug-resistant C. jejuni strain LZCJ isolated from a tumor patient with bloodstream infection. LZCJ was resistant to norfloxacin, ampicillin, ceftriaxone, ciprofloxacin and tetracycline. It showed high survival rate in serum and acidic environment. Whole genome sequencing (WGS) analysis revealed that strain LZCJ had a single chromosome of 1,629,078 bp (30.6 % G + C content) and belonged to the ST137 lineage. LZCJ shared the highest identity of 99.66 % with the chicken-derived C. jejuni MTVDSCj20. Four antimicrobial resistance genes (ARGs) were detected, bla(OXA-61), tet(O), gyrA (T86I), and cmeR (G144D and S207G). In addition, a 12,746 bp genomic island GI_LZCJ carrying 15 open reading frames (ORFs) including the resistance gene tet(O) was identified. Sequence analysis found that the GI_LZCJ was highly similar to the duck-derived C. jejuni ZS004, but with an additional ISChh1-like sequence. 137 non-synonymous mutations in motility related genes (flgF, fapR, flgS), capsular polysaccharide (CPS) coding genes (kpsE, kpsF, kpsM, kpsT), metabolism associated genes (nuoF, nuoG, epsJ, holB), and transporter related genes (comEA, gene0911) were confirmed in LZCJ compared with the best closed chicken-derived strain MTVDSCj20. Our study showed that C. jejuni strain LZCJ was highly similar to the chicken-derived strain MTVDSCj20 but with a lot of SNPs involved in motility, CPS and metabolism coding genes. This strain possessed a tet(O)-positive genomic island GI_LZCJ, which was closed to duck-derived C. jejuni ZS004, but with an additional ISChh1-like sequence. The above data indicated that the LZCJ strain may originate from foodborne bacteria on animals and the importance of continuous surveillance for the spread of foodborne bacteria.202439208964
3024110.8668Identification of ISVlu1-derived translocatable units containing optrA and/or fexA genes generated by homologous or illegitimate recombination in Lactococcus garvieae of porcine origin. The optrA gene encodes an ABC-F protein which confers cross-resistance to oxazolidinones and phenicols. Insertion sequence ISVlu1, a novel ISL3-family member, was recently reported to be involved in the transmission of optrA in Vagococcus lutrae. However, the role of ISVlu1 in mobilizing resistance genes has not yet fully explored. In this study, two complete and three truncated copies of ISVlu1 were found on plasmid pBN62-optrA from Lactococcus garvieae. Analysis of the genetic context showed that both optrA and the phenicols resistance gene fexA were flanked by the complete or truncated ISVlu1 copies. Moreover, three different-sized ISVlu1-based translocatable units (TUs) carrying optrA and/or fexA, were detected from pBN62-optrA. Sequence analysis revealed that the TU-optrA was generated by homologous recombination while TU-fexA and TU-optrA+fexA were the products of illegitimate recombinations. Importantly, conjugation assays confirmed that pBN62-optrA was able to successfully transfer into the recipient Enterococcus faecalis JH2-2. To our knowledge, this is the first report about an optrA-carrying plasmid in L. garvieae which could horizontally transfer into other species. More importantly, the ISVlu1-flanked genetic structures containing optrA and/or fexA were also observed in bacteria of different species, which underlines that ISVlu1 is highly active and plays a vital role in the transfer of some important resistance genes, such as optrA and fexA.202438479301
5873120.8667pDB2011, a 7.6 kb multidrug resistance plasmid from Listeria innocua replicating in Gram-positive and Gram-negative hosts. pDB2011, a multidrug resistance plasmid isolated from the foodborne Listeria innocua strain TTS-2011 was sequenced and characterized. Sequence analysis revealed that pDB2011 had a length of 7641 bp and contained seven coding DNA sequences of which two were annotated as replication proteins, one as a recombination/mobilization protein and one as a transposase. Furthermore, pDB2011 harbored the trimethoprim, spectinomycin and macrolide-lincosamide-streptogramin B resistance genes dfrD, spc and erm(A), respectively. However, pDB2011 was only associated with trimethoprim and spectinomycin resistance phenotypes and not with phenotypic resistance to erythromycin. A region of the plasmid encoding the resistance genes spc and erm(A) plus the transposase was highly similar to Staphylococcus aureus transposon Tn554. The dfrD gene was 100% identical to dfrD found in a number of Listeria monocytogenes isolates. Additionally, assessment of the potential host range of pDB2011 revealed that the plasmid was able to replicate in Lactococcus lactis subsp. cremoris MG1363 as well as in Escherichia coli MC1061 and DH5α. This study reports the first multidrug resistance plasmid in L. innocua. A large potential for dissemination of pDB2011 is indicated by its host range of both Gram-positive and Gram-negative bacteria.201323774482
2007130.8665Novel 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.201222890194
1515140.8665A novel transposon Tn7540 carrying bla(NDM-9) and fosA3 in chromosome of a pathogenic multidrug-resistant Salmonella enterica serovar Indiana isolated from human faeces. OBJECTIVES: Emergence of multidrug-resistant (MDR) Salmonella enterica serovar Indiana has raised global concern. Mobile genetic elements (MGEs) play vital roles in accelerating the dissemination of resistance genes in bacteria communities. The study aims to improve our understanding of the underlying resistance mechanisms and characterize the MGEs in a MDR S. Indiana isolate. METHODS: Here, we report the characteristics of a MDR pathogenic S. Indiana isolate. The antimicrobial susceptibility pattern of S. Indiana QT6365 was determined. The genomic structure of the chromosome and the plasmid, serotype, and multi-locus sequence type were analysed by whole genome sequencing. The circular form derived from IS26-flanked transposon was confirmed by reverse polymerase chain reaction and sequencing. RESULTS: S. Indiana QT6365 exhibited resistance to all tested antimicrobials except for aztreonam, amikacin, polymyxin, and tigecycline, was defined as MDR, and belonged to ST17. S. Indiana QT6365 was closely related with food resource S. Indiana C629 with similar resistance gene profiles. Multiple resistance genes are mainly carried by a novel transposon Tn7540 located on the chromosome and an IncHI2/HI2A/N plasmid. Sequence analysis and the formed circular intermediate suggested Tn7540 might be generated through homologous recombination by IS26-bounded translocatable units (IS26-fosA-IS26-intI1-dfrA12-aadA2-sul1-ISCR1-bla(NDM-9)-IS26). CONCLUSIONS: To the best of our knowledge, this is the first report of the novel chromosomal transposon possessing bla(NDM-9) and fosA3 in S. Indiana isolated from human specimen, which might facilitate the dissemination of resistance genes and should arouse serious awareness.202336854357
5209150.8664Complete Nucleotide Sequence of pGA45, a 140,698-bp IncFIIY Plasmid Encoding bla IMI-3-Mediated Carbapenem Resistance, from River Sediment. Plasmid pGA45 was isolated from the sediments of Haihe River using Escherichia coli CV601 (gfp-tagged) as recipients and indigenous bacteria from sediment as donors. This plasmid confers reduced susceptibility to imipenem which belongs to carbapenem group. Plasmid pGA45 was fully sequenced on an Illumina HiSeq 2000 sequencing system. The complete sequence of plasmid pGA45 was 140,698 bp in length with an average G + C content of 52.03%. Sequence analysis shows that pGA45 belongs to IncFIIY group and harbors a backbone region which shares high homology and gene synteny to several other IncF plasmids including pNDM1_EC14653, pYDC644, pNDM-Ec1GN574, pRJF866, pKOX_NDM1, and pP10164-NDM. In addition to the backbone region, plasmid pGA45 harbors two notable features including one bla IMI-3-containing region and one type VI secretion system region. The bla IMI-3-containing region is responsible for bacteria carbapenem resistance and the type VI secretion system region is probably involved in bacteria virulence, respectively. Plasmid pGA45 represents the first complete nucleotide sequence of the bla IMI-harboring plasmid from environment sample and the sequencing of this plasmid provided insight into the architecture used for the dissemination of bla IMI carbapenemase genes.201626941718
5405160.8664Characterization of florfenicol resistance genes in the coagulase-negative Staphylococcus (CoNS) isolates and genomic features of a multidrug-resistant Staphylococcus lentus strain H29. BACKGROUND: With the wide use of florfenicol to prevent and treat the bacterial infection of domestic animals, the emergence of the florfenicol resistance bacteria is increasingly serious. It is very important to elucidate the molecular mechanism of the bacteria's resistance to florfenicol. METHODS: The minimum inhibitory concentration (MIC) levels were determined by the agar dilution method, and polymerase chain reaction was conducted to analyze the distribution of florfenicol resistance genes in 39 CoNS strains isolated from poultry and livestock animals and seafood. The whole genome sequence of one multidrug resistant strain, Staphylococcus lentus H29, was characterized, and comparative genomics analysis of the resistance gene-related sequences was also performed. RESULTS: As a result, the isolates from the animals showed a higher resistance rate (23/28, 82.1%) and much higher MIC levels to florfenicol than those from seafood. Twenty-seven animal isolates carried 37 florfenicol resistance genes (including 26 fexA, 6 cfr and 5 fexB genes) with one carrying a cfr gene, 16 each harboring a fexA gene, 5 with both a fexA gene and a fexB gene and the other 5 with both a fexA gene and a cfr gene. On the other hand, all 11 isolates from seafood were sensitive to florfenicol, and only 3 carried a fexA gene each. The whole genome sequence of S. lentus H29 was composed of a chromosome and two plasmids (pH29-46, pH29-26) and harbored 11 resistance genes, including 6 genes [cfr, fexA, ant(6)-Ia, aacA-aphD, mecA and mph(C)] encoded on the chromosome, 4 genes [cfr, fexA, aacA-aphD and tcaA] on pH29-46 and 1 gene (fosD) on pH29-26. We found that the S. lentus H29 genome carried two identical copies of the gene arrays of radC-tnpABC-hp-fexA (5671 bp) and IS256-cfr (2690 bp), of which one copy of the two gene arrays was encoded on plasmid pH29-46, while the other was encoded on the chromosome. CONCLUSIONS: The current study revealed the wide distribution of florfenicol resistance genes (cfr, fexA and fexB) in animal bacteria, and to the best of our knowledge, this is the first report that one S. lentus strain carried two identical copies of florfenicol resistance-related gene arrays.202133413633
1754170.8664Transposons 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.202438593463
3013180.8662Nucleotide sequence and organization of the multiresistance plasmid pSCFS1 from Staphylococcus sciuri. OBJECTIVES: The multiresistance plasmid pSCFS1 from Staphylococcus sciuri was sequenced completely and analysed with regard to its gene organization and the putative role of a novel ABC transporter in antimicrobial resistance. METHODS: Plasmid pSCFS1 was transformed into Staphylococcus aureus RN4220, overlapping restriction fragments were cloned into Escherichia coli plasmid vectors and sequenced. For further analysis of the ABC transporter, a approximately 3 kb EcoRV-HpaI fragment was cloned into the staphylococcal plasmid pT181MCS and the respective S. aureus RN4220 transformants were subjected to MIC determination. RESULTS: A total of 14 ORFs coding for proteins of >100 amino acids were detected within the 17 108 bp sequence of pSCFS1. Five of them showed similarity to recombination/mobilization genes while another two were similar to plasmid replication genes. In addition to the previously described genes cfr for chloramphenicol/florfenicol resistance and erm(33) for inducible resistance to macrolide-lincosamide-streptogramin B resistance, a Tn554-like spectinomycin resistance gene and Tn554-related transposase genes were identified. Moreover, a novel ABC transporter was detected and shown to mediate low-level lincosamide resistance. CONCLUSION: Plasmid pSCFS1 is composed of various parts which show similarity to sequences known to occur on plasmids or transposons of Gram-positive, but also Gram-negative bacteria. It is likely that pSCFS1 represents the result of inter-plasmid recombination events also involving the truncation of a Tn554-like transposon.200415471995
812190.8662Characterization of plQ5 plasmid originating fromKlebsiella pneumoniae. plQ5 plasmid consists of a group of genes specifying resistance to ampicillin, chloramphenicol, carbencillin, kanamycin and trimethoprim-sulphamethoxazole. It is isolated inKlebslella pneumoniae ZD532, is about 26.8 Kb and is freely transmissible to various bacterial species of Gram-negative bacteria. Physical characterization revealed that plQ5 plasmid has a single site forHindill,BamHI,EcoRI and two sites forBglII restriction enzyme.199024429982