TRANSFERABLE - Word Related Documents




#
Rank
Similarity
Title + Abs.
Year
PMID
012345
304100.9942pCERC1, a small, globally disseminated plasmid carrying the dfrA14 cassette in the strA gene of the sul2-strA-strB gene cluster. Commensal Escherichia coli from healthy adult humans were screened for antibiotic resistance genes. Two unrelated strains contained the sul2 sulphonamide resistance gene and strAB streptomyicn resistance genes with the dfrA14 trimethoprim resistance gene cassette in the strA gene and conferred resistance to trimethoprim and sulphamethoxazole. A 6.8 kb plasmid, pCERC1, that contains these resistance genes was recovered and sequenced. Deletions were constructed, and the pCERC1 replication region was confined to a 1 kb segment carrying genes for RNAs that are closely related to the ColE1 replication initiation RNAs. Polymerase chain reaction assays, developed to detect the sul2-strA-strB gene cluster in this context, identified a streptomycin and sulphonamide resistance plasmid, pCERC2, identical to pCERC1 without the dfrA14 cassette in two further E. coli isolates. Bioinformatic analysis revealed plasmids similar to pCERC1 and two more members of this family. One, the probable progenitor, carries only the sul2 gene adjacent to the small mobile element CR2. The other has a variant resistance gene cluster that has evolved from pCERC2 via acquisition of the tet(A) tetracycline resistance determinant. pCERC1 and pCERC2 have been detected in many countries, indicating a global distribution and appear to have been circulating in Gram-negative bacteria for more than 25 years.201222416992
200210.9941IncHI1 plasmids mediated the tet(X4) gene spread in Enterobacteriaceae in porcine. The tigecycline resistance gene tet(X4) was widespread in various bacteria. However, limited information about the plasmid harboring the tet(X4) gene spread among the different species is available. Here, we investigated the transmission mechanisms of the tet(X4) gene spread among bacteria in a pig farm. The tet(X4) positive Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Enterobacter hormaeche were identified in the same farm. The whole genome sequencing (WGS) analysis showed that the K. pneumoniae belonged to ST727 (n = 11) and ST3830 (n = 1), E. cloacae and E. hormaeche belonged to ST524 (n = 1) and ST1862 (n = 1). All tet(X4) genes were located on the IncHI1 plasmids that could be conjugatively transferred into the recipient E. coli C600 at 30°C. Moreover, a fusion plasmid was identified that the IncHI1 plasmid recombined with the IncN plasmid mediated by ISCR2 during the conjugation from strains B12L to C600 (pB12L-EC-1). The fusion plasmid also has been discovered in a K. pneumoniae (K1L) that could provide more opportunities to spread antimicrobial resistance genes. The tet(X4) plasmids in these bacteria are derived from the same plasmid with a similar structure. Moreover, all the IncHI1 plasmids harboring the tet(X4) gene in GenBank belonged to the pST17, the newly defined pMLST. The antimicrobial susceptibility testing was performed by broth microdilution method showing the transconjugants acquired the most antimicrobial resistance from the donor strains. Taken together, this report provides evidence that IncHI1/pST17 is an important carrier for the tet(X4) spread in Enterobacteriaceae species, and these transmission mechanisms may perform in the environment.202337065147
175220.9940Genetic 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
303630.9940Complete 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
300940.9939Identification of a novel conjugative plasmid carrying the multiresistance gene cfr in Proteus vulgaris isolated from swine origin in China. The multiresistance gene cfr has a broad host range encompassing both Gram-positive and Gram-negative bacteria, and can be located on the chromosomes or on plasmids. In this study, a novel conjugative plasmid carrying cfr, designated as pPvSC3, was characterized in a Proteus vulgaris strain isolated from swine in China. Plasmid pPvSC3 is 284,528 bp in size and harbors 10 other antimicrobial resistance genes, making it a novel plasmid that differs from all known plasmids due to its unique backbone and repA gene. BLAST analysis of the plasmid sequence shows no significant homology to any known plasmid backbone, but shows high level homology to Providencia rettgeri strain CCBH11880 Contig_9, a strain isolated from surgical wound in Brazil, 2014. There are two resistance-determining regions in pPvSC3, a cfr-containing region and a multidrug-resistant (MDR) region. The cfr-containing region is flanked by IS26, which could be looped out via IS26-mediated recombination. The MDR region harbors 10 antimicrobial resistance genes carried by various DNA segments that originated from various sources. Plasmid pPvSC3 could be successfully transferred to Escherichia coli by conjugation. In summary, we have characterized a novel conjugative plasmid pPvSC3 carrying the multiresistance gene cfr and 10 other antimicrobial resistance genes, and consider that this novel type of plasmid deserves attention.201931499097
301850.9939The large Bacillus plasmid pTB19 contains two integrated rolling-circle plasmids carrying mobilization functions. Plasmid pTB19 is a 27-kb plasmid originating from a thermophilic Bacillus species. It was shown previously that pTB19 contains an integrated copy of the rolling-circle type plasmid pTB913. Here we describe the analysis of a 4324-bp region of pTB19 conferring resistance to tetracycline. The nucleotide sequence of this region revealed all the characteristics of a second plasmid replicating via the rolling-circle mechanism. This sequence contained (i) the tetracycline resistance marker of pTB19, which is highly similar to other tetL-genes of gram-positive bacteria; (ii) a hybrid mob gene, which bears relatedness to both the mob-genes of pUB110 and pTB913; (iii) a palU type minus origin identical to those of pUB110 and pTB913; and (iv) a plus origin of replication similar to that of pTB913. A repB-type replication initiation gene sequence identical to that of pTB913 was present, which lacked the middle part (492 bp), thus preventing autonomous replication of this region. The hybrid mob gene was functional in conjugative mobilization of plasmids between strains of Bacillus subtilis.19911946749
200160.9938Identification of plasmids co-carrying cfr(D)/optrA and cfr(D2)/poxtA linezolid resistance genes in two Enterococcus avium isolates from swine brain. Oxazolidinones are critically important antibiotics to treat human infections caused by multidrug-resistant bacteria, therefore the occurrence of linezolid-resistant enterococci from food-producing animals poses a serious risk to human health. In this study, Enterococcus avium 38157 and 44917 strains, isolated from the brain of two unrelated piglets, were found to carry the linezolid resistance genes cfr(D)-optrA, and cfr(D2)-poxtA, respectively. Whole genome sequencing analysis of E. avium 38157 revealed that the genes were co-located on the 36.5-kb pEa_cfr(D)-optrA plasmid showing high identity with the pAT02-c of Enterococcus faecium AT02 from pet food. The optrA region, was 99% identical to the one of the pAv-optrA plasmid from a bovine Aerococcus viridans strain, whereas the cfr(D) genetic context was identical to that of the plasmid 2 of E. faecium 15-307.1. pEa_cfr(D)-optrA was not transferable to enterococcal recipients. In E. avium 44917 a cfr(D)-like gene, named cfr(D2), and the poxtA gene were co-located on the transferable 42.6-kb pEa-cfr(D2)-poxtA plasmid 97% identical to the Tn6349 transposon of the human MRSA AOUC-0915. The cfr(D2) genetic context, fully replaced the Tn6644 that in S. aureus AOUC-0915 harbor the cfr gene. In conclusion, this is, the best of our knowledge, the first report of the new cfr(D2) gene variant. The occurrence of plasmids co-carrying two linezolid resistance genes in enterococci from food-producing animals needs close surveillance to prevent their spread to human pathogens.202337116421
150970.9937Characterization of plasmids harbouring qnrS1, qnrB2 and qnrB19 genes in Salmonella. OBJECTIVES: The aim of this study was to identify and characterize plasmids carrying qnrS1, qnrB2 and qnrB19 genes identified in Salmonella strains from The Netherlands. The identification of plasmids may help to follow the dissemination of these resistance genes in different countries and environments. METHODS: Plasmids from 33 qnr-positive Salmonella strains were transferred to Escherichia coli and analysed by restriction, Southern blot hybridization, PCR and sequencing of resistance determinants. They were also assigned to incompatibility groups by PCR-based replicon typing, including three additional PCR assays for the IncU, IncR and ColE groups. The collection included isolates from humans and one from chicken meat. RESULTS: Five IncN plasmids carrying qnrS1, qnrB2 and qnrB19 genes were identified in Salmonella enterica Bredeney, Typhimurium PT507, Kentucky and Saintpaul. qnrS1 genes were also located on three further plasmid types, belonging to the ColE (in Salmonella Corvallis and Anatum), IncR (in Salmonella Montevideo) and IncHI2 (in Salmonella Stanley) groups. CONCLUSIONS: Multiple events of mobilization, transposition and replicon fusion generate the complexity observed in qnr-positive isolates that are emerging worldwide. Despite the fact that the occurrence of qnr genes in bacteria from animals is scarcely reported, these genes are associated with genetic elements and located on plasmids that are recurrent in animal isolates.200919001452
244880.9937Emerging coexistence of three PMQR genes on a multiple resistance plasmid with a new surrounding genetic structure of qnrS2 in E. coli in China. BACKGROUND: Quinolones are commonly used for treatment of infections by bacteria of the Enterobacteriaceae family. However, the rising resistance to quinolones worldwide poses a major clinical and public health risk. This study aimed to characterise a novel multiple resistance plasmid carrying three plasmid-mediated quinolone resistance genes in Escherichia coli clinical stain RJ749. METHODS: MICs of ceftriaxone, cefepime, ceftazidime, ciprofloxacin, and levofloxacin for RJ749 and transconjugant c749 were determined by the Etest method. Conjugation was performed using sodium azide-resistant E. coli J53 strain as a recipient. The quinolone resistance-determining regions of gyrA, gyrB, parC, and parE were PCR-amplified. RESULTS: RJ749 was highly resistant to quinolones, while c749 showed low-level resistance. S1-nuclease pulsed-field gel electrophoresis revealed that RJ749 and c749 both harboured a plasmid. PCR presented chromosomal mutation sites of the quinolone resistance-determining region, which mediated quinolone resistance. The c749 genome comprised a single plasmid, pRJ749, with a multiple resistance region, including three plasmid-mediated quinolone resistance (PMQR) genes (aac (6')-Ib-cr, qnrS2, and oqxAB) and ten acquired resistance genes. One of the genes, qnrS2, was shown for the first time to be flanked by two IS26s. Three IS26-mediated circular molecules carrying the PMQR genes were detected. CONCLUSIONS: We revealed the coexistence of three PMQR genes on a multiple resistance plasmid and a new surrounding genetic structure of qnrS2 flanked by IS26 elements. IS26 plays an important role in horizontal spread of quinolone resistance.202032293532
151490.9936Widespread prevalence and molecular epidemiology of tet(X4) and mcr-1 harboring Escherichia coli isolated from chickens in Pakistan. The emergence and spread of plasmid-mediated tigecycline resistance gene tet(X4) and colistin resistance gene mcr-1 in Escherichia coli (E. coli) pose a potential threat to public health, due to the importance of colistin and tigecycline for treating serious clinical infections. However, the characterization of bacteria coharboring both genes was few reported. Here, we described the molecular epidemiology of tet(X4) and mcr-1 harboring E. coli strains of chicken origin in Pakistan, with methods including PCR, antimicrobial susceptibility testing, DNA transfer assays, plasmid replicon typing, whole-genome sequencing and bioinformatics analysis. The tet(X4) gene was identified in 36 isolates exhibiting high levels of tigecycline resistance (MICs, 16-128 mg/L). Worryingly, 24 of the 36 tet(X4)-bearing isolates were confirmed as colistin resistance, positive for plasmid-borne mcr-1. We observed the prevalence of tet(X4)-bearing IncFII plasmid with mcr-1-bearing IncI2 plasmid in 12 E. coli isolates, with a high co-transfer frequency except for one strain PK8233, in which tet(X4)- and mcr-1-bearing plasmids were non-transferable. Coexistence of tet(X4)-bearing IncFII plasmid with mcr-1-carrying multidrug-resistant (MDR) IncHI2 plasmid was also identified in 10 E. coli isolates, and a relatively low co-transfer frequency was obtained except PK8575, in which mcr-1 was non-transferable. The transferability of pPK8275-tetX in PK8275 and pPK8233-tetX in PK8233, that could transfer from E. coli J53 to C600 by conjugation, was interfered by certain factors in PK8275 and PK8233. This may provide new insights to prevent and control the spread of antibiotic resistance genes. Two strains were reported to co-carry tet(X4)-positive IncQ1 plasmid and mcr-1-positive IncI2 plasmid. Convergence of tet(X4) and mcr-1 genes in E. coli by conjugative or mobilizable plasmids may lead to potentially widespread transmission of such resistance genes, which may incur antibiotic-resistance crisis globally.202234599956
3055100.9936Tn1545: a conjugative shuttle transposon. Tn1545, from Streptococcus pneumoniae BM4200, confers resistance to kanamycin (aphA-3), erythromycin (ermAM) and tetracycline (tetM). The 25.3 kb element is self-transferable to various Gram-positive bacterial genera where it transposes. Tn1545 was cloned in its entirety in the recombination deficient Escherichia coli HB101 where it was unstable. The three resistance genes aphA-3, ermAM and tetM were expressed but were not transferable to other E. coli cells. Tn1545 transposed from the hybrid plasmid to multiple sites of the chromosome of its new host. The element re-transposed, at a frequency of 5 X 10(-9), from the chromosome to various sites of a conjugative plasmid where it could be lost by apparently clean excision. The element transformed and transposed to the chromosome of Bacillus subtilis. The properties of the conjugative shuttle transposon Tn1545 may account for the recent emergence of genes from Gram-positive bacteria in Gram-negative organisms.19873035335
5867110.9936Molecular 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.200818786941
3040120.9936Similarity in the Structure of tetD-Carrying Mobile Genetic Elements in Bacterial Strains of Different Genera Isolated from Cultured Yellowtail. Structure analysis was performed on the antibiotic-resistance-gene region of conjugative plasmids of four fish farm bacteria.The kanamycin resistance gene, IS26, and tetracycline resistance gene (tetA(D)) were flanked by two IS26s in opposite orientation in Citrobacter sp. TA3 and TA6, and Alteromonas sp. TA55 from fish farm A. IS26-Inner was disrupted with ISRSB101. The chloramphenicol resistance gene, IS26 and tetA (D) were flanked by two IS26s in direct orientation in Salmonella sp. TC67 from farm C. Structures of tetA (D) and IS26 were identical among the four bacteria, but there was no insertion within the IS26-Inner of Salmonella sp. TC67. Horizontal gene transfer between the strains of two different genera in fish farm A was suggested by the structure homologies of mobile genetic elements and antibiotic resistance genes.201627667524
3039130.9935Distinct recent lineages of the strA- strB streptomycin-resistance genes in clinical and environmental bacteria. We report the linkage of the strA-strB streptomycin-resistance genes with Class 1 integron sequences on pSTR1, a 75-kb multiple antibiotic-resistance plasmid from Shigella flexneri. strA-strB had previously been detected only within Tn 5393, a Tn 3-family transposon, and on small nonconjugative broad-host-range plasmids such as RSF1010. The geographic range of Tn 5393 was also extended to Pseudomonas spp. isolated from apple trees in New Zealand and soil in the USA. Comparative sequence analyses indicated that strA-strB from Tn 5393 and nonconjugative plasmids constitute distinct recent lineages with strA-strB from pSTR1 intermediate between the other two. The carriage of strA-strB within an integron, a transposon, and on broad-host-range plasmids has facilitated the world-wide dissemination of this determinant among at least 21 bacterial genera.200212029529
3024140.9935Identification 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
2004150.9935Deciphering the Structural Diversity and Classification of the Mobile Tigecycline Resistance Gene tet(X)-Bearing Plasmidome among Bacteria. The emergence of novel plasmid-mediated resistance genes constitutes a great public concern. Recently, mobile tet(X) variants were reported in diverse pathogens from different sources. However, the diversity of tet(X)-bearing plasmids remains largely unknown. In this study, the phenotypes and genotypes of all the tet(X)-positive tigecycline-resistant strains isolated from a slaughterhouse in China were characterized by antimicrobial susceptibility testing, conjugation, pulsed-field gel electrophoresis with S1 nuclease (S1-PFGE), and PCR. The diversity and polymorphism of tet(X)-harboring strains and plasmidomes were investigated by whole-genome sequencing (WGS) and single-plasmid-molecule analysis. Seventy-four tet(X4)-harboring Escherichia coli strains and one tet(X6)-bearing Providencia rettgeri strain were identified. The tet(X4)-bearing elements in 27 strains could be transferred to the recipient strain via plasmids. All tet(X4)-bearing plasmids isolated in this study and 15 tet(X4)-bearing plasmids reported online were analyzed. tet(X4)-bearing plasmids ranged from 9 to 294 kb and were categorized as ColE2-like, IncQ, IncX1, IncA/C2, IncFII, IncFIB, and hybrid plasmids with different replicons. The core tet(X4)-bearing genetic contexts were divided into four major groups: ISCR2-tet(X4)-abh, △ISCR2-abh-tet(X4)-ISCR2, ISCR2-abh-tet(X4)-ISCR2-virD2-floR, and abh-tet(X4)-ISCR2-yheS-cat-zitR-ISCR2-virD2-floR Tandem repeats of tet(X4) were universally mediated by ISCR2 Different tet(X)-bearing strains existed in the same microbiota. Reorganization of tet(X4)-bearing multidrug resistance plasmids was found to be mediated by IS26 and other homologous regions. Finally, single-plasmid-molecule analysis captured the heterogenous state of tet(X4)-bearing plasmids. These findings significantly expand our knowledge of the tet(X)-bearing plasmidome among microbiotas, which establishes a baseline for investigating the structure and diversity of human, animal, and environmental tigecycline resistomes. Characterization of tet(X) genes among different microbiotas should be performed systematically to understand the evolution and ecology.IMPORTANCE Tigecycline is an expanded-spectrum tetracycline used as a last-resort antimicrobial for treating infections caused by superbugs such as carbapenemase-producing or colistin-resistant pathogens. Emergence of the plasmid-mediated mobile tigecycline resistance gene tet(X4) created a great public health concern. However, the diversity of tet(X4)-bearing plasmids and bacteria remains largely uninvestigated. To cover this knowledge gap, we comprehensively identified and characterized the tet(X)-bearing plasmidome in different sources using advanced sequencing technologies for the first time. The huge diversity of tet(X4)-bearing mobile elements demonstrates the high level of transmissibility of the tet(X4) gene among bacteria. It is crucial to enhance stringent surveillance of tet(X) genes in animal and human pathogens globally.202032345737
5456160.9935Detection of the enterococcal oxazolidinone/phenicol resistance gene optrA in Campylobacter coli. The transferable optrA gene encodes an ABC-F protein which confers resistance to oxazolidinones and phenicols, and has so far been detected exclusively in Gram-positive bacteria, including enterococci, staphylococci and streptococci. Here, we identified for the first time the presence of optrA in naturally occurring Gram-negative bacteria. Seven optrA-positive Campylobacter coli were identified from 563 Campylobacter isolates of animal origin from Guangdong (n = 1, chicken) and Shandong (n = 6, duck) provinces of China in 2017-2018. The detected optrA genes were functionally active and mediated resistance or elevated minimal inhibitory concentrations of linezolid, florfenicol and chloramphenicol in the respective C. coli isolates. The optrA gene, together with other transferable resistance genes, such as fexA, catA9, tet(O), tet(L), erm(A)-like, spc, or aadE, was located in two different chromosome-borne multidrug resistance genomic islands (MDRGIs). In both MDRGIs, complete or truncated copies of the insertion sequence IS1216E were present in the vicinity of optrA. The IS1216E-bracketed genetic environment of optrA was almost identical to the optrA regions on enterococcal plasmids, suggesting that the optrA in Campylobacter probably originated from Enterococcus spp.. Moreover, the formation of an optrA-carrying translocatable unit by recombination of IS1216E indicated that this IS element may play an important role in the horizontal transfer of optrA in Campylobacter. Although optrA was only found in a small number of C. coli isolates, enhanced surveillance is needed to monitor the distribution and the potential emergence of optrA in Campylobacter.202032605743
5868170.9935Evaluation 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.200919484299
963180.9934The detection of fosfomycin resistance genes in Enterobacteriaceae from pets and their owners. The aim of this study was to investigate the prevalence of fosfomycin resistance and molecular characteristic of fosfomycin-resistant strains isolated from companion animals and their owners. A total of 171 samples collected from pets and pet owners in a Chinese veterinary teaching hospital were screened for the presence of phenotype and genotype of fosfomycin-resistance by selective media containing fosfomycin and PCR & sequencing. Among 171 samples tested, nineteen isolates were resistant to fosfomycin. Sixteen and three of these fosfomycin-resistant isolates were positive for fosA3 and fosA genes, respectively. The fosA3 gene was detected both in chromosomes and plasmids in bacteria. All of the fosA3 gene-positive isolates except one were CTX-M producers and nearly half (7/16) of them also harbored the rmtB gene. The fosA3 gene-carrying plasmids, which were readily transferrable to recipient E. coli J53 by conjugation, conferred resistance to multiple antimicrobial agents. Genetic structures were IS26-385bp-fosA3-1810bp-IS26 (n=11) and IS26-385bp-fosA3-588bp-IS26 (n=5). Molecular typing indicated that two fosA3-positive isolates from dogs were genetically identical to the isolates from the pet owners. Our results indicated that active transmission of fosA3-mediated fosfomycin resistance has occurred among Enterobacteriaceae isolated from pets and their owners by both horizontal transfer and clonal expansion.201627599932
3017190.9934The ancient small mobilizable plasmid pALWED1.8 harboring a new variant of the non-cassette streptomycin/spectinomycin resistance gene aadA27. The small mobilizable plasmid pALWED1.8 containing a novel variant of the streptomycin/spectinomycin resistance gene aadA27 was isolated from the permafrost strains of Acinetobacter lwoffii. The 4135bp plasmid carries mobА and mobC genes that mediate its mobilization by conjugative plasmids. The nucleotide sequences of mobА and mobC are similar to those of mobilization genes of the modern plasmid pRAY* and its variants, which contain aadB gene, and are widespread among the pathogenic strains of Acinetobacter baumannii. Almost identical pALWED1.8 variants were detected in modern environmental Аcinetobacter strains. A highly similar plasmid was revealed in a strain of Acinetobacter parvus isolated from mouse intestine. Furthermore, we discovered six previously unidentified variants of plasmids related to pALWED1.8 and pRAY* in public databases. In contrast to most known variants of aadA which are cassette genes associated with integrons, the aadA27 variant harbored by pALWED1.8 is a non-cassette, autonomously transcribed gene. Non-cassette aadA genes with 96% sequence identity to aadA27 were detected in the chromosomes of Acinetobacter gyllenbergii and several uncharacterized strains of Аcinetobacter sp. Moreover, we revealed that the autonomous aadA-like genes are present in the chromosomes of many gram-positive and gram-negative bacteria. The phylogenetic analysis of amino acid sequences of all identified AadA proteins showed the following: (i) cassette aadA genes form a separate monophyletic group and mainly reside on plasmids and (ii) chromosomal non-cassette aadA genes are extremely diverse and can be inherited both vertical and via horizontal gene transfer.201626896789