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Journal articles on the topic "Staphylococcus aureus plasmids"

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Zorbas, Ioannis, Robert T. Hall, Sue L. Hall, William G. Barnes, and Marvin Rogolsky. "Molecular analyses of conjugative, gentamicin-resistance plasmids from staphylococcal clinical isolates." Canadian Journal of Microbiology 34, no. 9 (September 1, 1988): 1050–57. http://dx.doi.org/10.1139/m88-185.

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Gentamicin-resistant Staphylococcus aureus and Staphylococcus epidermidis strains which were isolated from infants with staphylococcal bacteremia were analyzed for the presence of self-transmissible gentamicin-resistance (Gmr) plasmids. Conjugative GMr plasmids of approximately 43.8–63 kilobases (kb) were found in all S. aureus strains. Inter- and intra-species transfer of Gmr plasmids by conjugation was observed from S. aureus to S. aureus and to S. epidermidis recipient strains. However, neither inter- nor intra-species transfer of gentamicin resistance by conjugation was observed with nine out of nine S. epidermidis donor strains which were mated with either S. epidermidis or S. aureus recipient strains. These conjugative Gmr plasmids were unable to comobilize a smaller (15-kb) plasmid present in all but two S. aureus clinical isolates. Many of the conjugative Gmr plasmids also carried genetic determinants for kanamycin, tobramycin, neomycin, and ethidium bromide resistance, and for β-lactamase synthesis. EcoRI restriction endonuclease digests of the S. aureus Gmr conjugative plasmids revealed three different digestion patterns. Four EcoRI restriction endonuclease digestion fragments of 15, 11.4, 6.3, and 4.6 kb in size were common to all plasmids. These plasmids and conjugative Gmr staphylococcal plasmids from other geographical regions shared restriction digestion fragments of similar molecular weights. DNA hybridization with biotinylated S. aureus plasmid pIZ7814 DNA revealed a high degree of homology among these plasmids. A 50.9-kb plasmid from one of the nonconjugative S. epidermidis clinical isolates showed homology with the probe DNA but lacked a portion of a 6.3-kb fragment which was present in all conjugative plasmids and believed to carry much genetic information for conjugation.
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Udo, E. E., L. E. Jacob, and E. M. Mokadas. "Conjugative transfer of high-level mupirocin resistance from Staphylococcus haemolyticus to other staphylococci." Antimicrobial Agents and Chemotherapy 41, no. 3 (March 1997): 693–95. http://dx.doi.org/10.1128/aac.41.3.693.

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A conjugative plasmid, pXU10, encoding high-level mupirocin resistance was transferred from a Staphylococcus haemolyticus isolate, CN216, to other coagulase-negative staphylococci and a restriction deficient Staphylococcus aureus strain, XU21, but not to clinical isolates or a restriction-proficient laboratory strain (strain WBG541) of S. aureus. However, from XU21 it was cotransferred with a 3.5-kb chloramphenicol resistance plasmid to WBG541. The results demonstrated the ability of pXU10 to mobilize nonconjugative plasmids.
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DD Moro. "Antibiotic susceptibility pattern and plasmid profiles of nasal staphylococci from apparently healthy Nigerians." World Journal of Biology Pharmacy and Health Sciences 6, no. 1 (April 30, 2021): 019–25. http://dx.doi.org/10.30574/wjbphs.2021.6.1.0035.

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A total of 480 nasal samples from apparently healthy Nigerian students were collected aseptically and analyzed bacteriologically. Staphylococci were recovered from 432 (90%) of the subjects, constituting 288 (66.7%) and 144 (33.3%) of S. aureus and S. epidermidis respectively. The in-vitro antibiotic susceptibility testing using the disc diffusion technique showed high multiple resistance to the most commonly used antibiotics by Staphylococcus aureus such as penicillin (98.6%), ampicillin (97.2%), tetracycline (95.8%) and streptomycin (84.7%), but less resistance to erythromycin (9.7%), rocephin (8.3%), peflacin (4.2%) respectively. The S. epidermis showed less resistance to all the antibiotics tested. Sixty percent of S. aureus harbored plasmids which molecular sizes ranged from 0.1 to 12.0 kilobases. The high prevalence of multiple antibiotic resistance appear to be plasmid mediated as plasmid profile analysis showed that about 90% of S. aureus harbored plasmids
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Navaratna, Maduwe A. D. B., Hans-Georg Sahl, and John R. Tagg. "Two-Component Anti-Staphylococcus aureusLantibiotic Activity Produced by Staphylococcus aureusC55." Applied and Environmental Microbiology 64, no. 12 (December 1, 1998): 4803–8. http://dx.doi.org/10.1128/aem.64.12.4803-4808.1998.

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ABSTRACT Staphylococcus aureus C55 was shown to produce bacteriocin activity comprising three distinct peptide components, termed staphylococcins C55α, C55β, and C55γ. The three peptides were purified to homogeneity by a simple four-step purification procedure that consisted of ammonium sulfate precipitation followed by XAD-2 and reversed-phase (C8 and C18) chromatography. The yield following C8 chromatography was about 86%, with a more-than-300-fold increase in specific activity. When combined in approximately equimolar amounts, staphylococcins C55α and C55β acted synergistically to kill S. aureus or Micrococcus luteus but not S. epidermidis strains. The N-terminal amino acid sequences of all three peptides were obtained and staphylococcins C55α and C55β were shown to be lanthionine-containing (lantibiotic) molecules with molecular weights of 3,339 and 2,993, respectively. The C55γ peptide did not appear to be a lantibiotic, nor did it augment the inhibitory activities of staphylococcin C55α and/or C55β. Plasmids of 2.5 and 32.0 kb are present in strain C55, and following growth of this strain at elevated temperature (42°C), a large proportion of the progeny failed to produce strong bacteriocin activity and also lost the 32.0-kb plasmid. Protoplast transformation of these bacteria with purified 32-kb plasmid DNA regenerates the ability to produce the strong bacteriocin activity.
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Amirsoleimani, Atena, Gail Brion, and Patrice Francois. "Co-Carriage of Metal and Antibiotic Resistance Genes in Sewage Associated Staphylococci." Genes 12, no. 10 (September 23, 2021): 1473. http://dx.doi.org/10.3390/genes12101473.

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Controlling spread of resistance genes from wastewater to aquatic systems requires more knowledge on how resistance genes are acquired and transmitted. Whole genomic sequences from sewage-associated staphylococcus isolates (20 S. aureus, 2 Staphylococcus warneri, and 2 Staphylococcus delphini) were analyzed for the presence of antibiotic resistance genes (ARGs) and metal resistance genes (MRGs). Plasmid sequences were identified in each isolate to investigate co-carriage of ARGs and MRGs within. BLASTN analysis showed that 67% of the isolates carried more than one ARG. The carriage of multiple plasmids was observed more in CC5 than CC8 S. aureus strains. Plasmid exchange was observed in all staphylococcus species except the two S. delphini isolates that carried multiple MRGs, no ARGs, and no plasmids. 85% of S. aureus isolates carried the blaZ gene, 76% co-carried blaZ with cadD and cadX, with 62% of these isolates carrying blaZ, cadD, and cadX on the same plasmid. The co-carriage of ARGs and MRGs in S. warneri isolates, and carriage of MRGs in S. delphini, without plasmids suggests non-conjugative transmission routes for gene acquisition. More studies are required that focus on the transduction and transformation routes of transmission to prevent interspecies exchange of ARGs and MRGs in sewage-associated systems.
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Bjorland, Jostein, Terje Steinum, Marianne Sunde, Steinar Waage, and Even Heir. "Novel Plasmid-Borne Gene qacJ Mediates Resistance to Quaternary Ammonium Compounds in Equine Staphylococcus aureus, Staphylococcus simulans, and Staphylococcus intermedius." Antimicrobial Agents and Chemotherapy 47, no. 10 (October 2003): 3046–52. http://dx.doi.org/10.1128/aac.47.10.3046-3052.2003.

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ABSTRACT We identified a novel plasmid-borne gene (designated qacJ) encoding resistance to quaternary ammonium compounds (QACs) in three staphylococcal species associated with chronic infections in four horses. qacJ was located on a 2,650-bp plasmid (designated pNVH01), a new member of the pC194 family of rolling-circle replication plasmids. The 107-amino-acid protein, QacJ, showed similarities to known proteins of the small multidrug resistance family: Smr/QacC (72.5%), QacG (82.6%), and QacH (73.4%). The benzalkonium chloride MIC for a qacJ-containing recombinant was higher than those for otherwise isogenic recombinants expressing Smr, QacG, or QacH. Molecular epidemiological analyses by pulsed-field gel electrophoresis suggested both the clonal spread of a qacJ-harboring Staphylococcus aureus strain and the horizontal transfer of pNVH01 within and between different equine staphylococcal species. The presence of pNVH01 of identical nucleotide sequence in different staphylococcal species suggests that recent transfer has occurred. In three of the horses, a skin preparation containing cetyltrimethylammonium bromide had been used extensively for several years; this might explain the selection of staphylococci harboring the novel QAC resistance gene.
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Pyzik, E., and A. Marek. "Plasmid profile analysis and evaluation of antibiotic susceptibility of Staphylococcus aureus strains isolated from table chicken eggs." Polish Journal of Veterinary Sciences 16, no. 2 (June 1, 2013): 307–12. http://dx.doi.org/10.2478/pjvs-2013-0042.

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AbstractThe aim of this study was to isolate and characterize Staphylococcus aureus bacteria present on the shell surfaces and in the contents of chicken eggs, taking into account their phenotypic properties, antibiotic susceptibility patterns, and the presence of plasmid DNA. The study included 90 table chicken eggs from laying farms situated in the vicinity of Lublin. A total of 105 bacterial strains identified as Staphylococcus were isolated from the material, of which 18 (17.14%) were of the species Staphylococcus aureus. All 18 S. aureus strains were found to be resistant to at least one of the antibiotics tested, while some (55.55%) showed resistance to five or more of the 17 therapeutic agents. The greatest number of strains showed resistance to erythromycin (66.66%), tetracycline (66.66%), oxytetracycline (61.11%), penicillin G (50%), and amoxicillin (44.44%). The plasmid profile analysis of the S. aureus strains made it possible to evaluate the dependence between antibiotic susceptibility and the presence of plasmids in particular isolates. The results showed that plasmids in various quantities and of varying molecular weights were isolated from 17 of the strains. Most often isolated were small plasmids, of 5.6 kb - from 11 of the S. aureus strains (61.11%), 2.5 kb - from 9 strains (50%), 4.1 kb - from 8 (44.44%), and 4.6 kb - from 7 (38.88%) of the strains.
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Firth, Neville, Sumalee Apisiridej, Tracey Berg, Brendon A. O'Rourke, Steve Curnock, Keith G. H. Dyke, and Ronald A. Skurray. "Replication of Staphylococcal Multiresistance Plasmids." Journal of Bacteriology 182, no. 8 (April 15, 2000): 2170–78. http://dx.doi.org/10.1128/jb.182.8.2170-2178.2000.

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ABSTRACT Based on structural and functional properties, three groups of large staphylococcal multiresistance plasmids have been recognized, viz., the pSK1 family, pSK41-like conjugative plasmids, and β-lactamase–heavy-metal resistance plasmids. Here we describe an analysis of the replication functions of a representative of each of these plasmid groups. The replication initiation genes from theStaphylococcus aureus plasmids pSK1, pSK41, and pI9789::Tn552 were found to be related to each other and to the Staphylococcus xylosus plasmid pSX267 and are also related to rep genes of several plasmids from other gram-positive genera. Nucleotide sequence similarity between pSK1 and pI9789::Tn552 extended beyond theirrep genes, encompassing upstream divergently transcribed genes, orf245 and orf256, respectively. Our analyses revealed that genes encoding proteins related to the deducedorf245 product are variously represented, in several types of organization, on plasmids possessing six seemingly evolutionarily distinct types of replication initiation genes and including both theta-mode and rolling-circle replicons. Construction of minireplicons and subsequent functional analysis demonstrated that orf245is required for the segregational stability of the pSK1 replicon. In contrast, no gene equivalent to orf245 is evident on the conjugative plasmid pSK41, and a minireplicon encoding only the pSK41 rep gene was found to exhibit a segregational stability approaching that of the parent plasmid. Significantly, the results described establish that many of the large multiresistance plasmids that have been identified in clinical staphylococci, which were formerly presumed to be unrelated, actually utilize an evolutionarily related theta-mode replication system.
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Anthonisen, I. L., M. Sunde, T. M. Steinum, M. S. Sidhu, and H. Sørum. "Organization of the Antiseptic Resistance Gene qacA and Tn552-Related β-Lactamase Genes in Multidrug- Resistant Staphylococcus haemolyticus Strains of Animal and Human Origins." Antimicrobial Agents and Chemotherapy 46, no. 11 (November 2002): 3606–12. http://dx.doi.org/10.1128/aac.46.11.3606-3612.2002.

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ABSTRACT A part (12 kb) of a plasmid containing the β-lactamase genes of Tn552, the disinfectant resistance gene qacA, and flanking DNA has been cloned from a Staphylococcus haemolyticus isolate and sequenced. This region was used to map the corresponding regions in six other multiresistant S. haemolyticus isolates of human and animal origin. The organizations of the genetic structures were almost identical in all isolates studied. The β-lactamase and qacA genes from S. haemolyticus have >99.9% identities at the nucleotide level with the same genes from S. aureus, demonstrating that various staphylococcal species able to colonize animal and human hosts can exchange the genetic elements involved in resistance to antibiotics and disinfectants. The use of antibiotics and disinfectants in veterinary practice and animal husbandry may also contribute to the selection and maintenance of resistance factors among the staphylococcal species. Different parts of the 12-kb section analyzed had high degrees of nucleotide identity with regions from several other different Staphylococcus aureus plasmids. This suggests the contribution of interplasmid recombination in the evolutionary makeup of this 12-kb section involving plasmids that can intermingle between various staphylococcal species. The lateral spread of resistance genes between various staphylococcal species is probably facilitated by the generation of large multiresistance plasmids and the subsequent interspecies exchange of them.
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Scharn, Caitlyn R., Fred C. Tenover, and Richard V. Goering. "Transduction of Staphylococcal Cassette ChromosomemecElements between Strains of Staphylococcus aureus." Antimicrobial Agents and Chemotherapy 57, no. 11 (August 12, 2013): 5233–38. http://dx.doi.org/10.1128/aac.01058-13.

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ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) is a well-known public health concern. However, the means by which methicillin resistance genes are transferred among staphylococci in nature remains unknown. Older scientific literature suggests transduction as a means ofmecAtransfer, but the optimal conditions are reported to require plasmids and potentially a lysogenic phage. These reports preceded discovery of the staphylococcal cassette chromosomemec(SCCmec) elements. We undertook studies to confirm and clarify the conditions promoting transduction of SCCmecinS. aureuspopulations using well-characterized donor and recipient strains primarily of the USA300 lineage. Both bacteriophages 80α and 29 were capable of transducing SCCmectype IV and SCCmectype I to recipient strains ofS. aureus. Pulsed-field gel electrophoresis andmec-associateddrutyping were used to confirm the identity of the transductants. Transfer ofmecAvia transduction occurred at low frequency and required extended selection times formecAgene expression and the presence of a penicillinase plasmid in the recipient. However, interference with the process by clavulanic acid and the necessity of lysogeny with ϕ11 in the recipient or the presence of a small (4-kb) tetracycline resistance plasmid, as previously reported, were not confirmed. SCCmectransduction was occasionally associated with substantial deletions or truncation of SCCmecand the arginine catabolic metabolic element in USA300 recipients. Overall, these data clarify the conditions required for SCCmectransduction and document that rearrangements may occur during the process.
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Dissertations / Theses on the topic "Staphylococcus aureus plasmids"

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Walters, John Anthony. "Replication of plasmids of Staphylococcus aureus." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315767.

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Catchpole, Ian R. "Studies of small plasmids of Staphylococcus aureus." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253298.

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Sohail, Muhammad. "The study of plasmid-plasmid and plasmid-chromosome interactions in Staphylococcus aureus." Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:5f5149a5-3d0f-4900-bd0f-be6e859bfa89.

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S. aureus 1054. The recombination occurs by a novel method. The data show that pSl or pΔD contribute the site for recombination and that the gene(s) for the protein(s) involved in recombination are encoded on pOX1054 or the 1054 chromosome. Integration of the plasmids into the chromosome of 1054 was not detected.
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Needham, Christine. "The basis of genetic rearrangements in mupirocin resistance plasmids." Thesis, University of Oxford, 1994. http://ora.ox.ac.uk/objects/uuid:52f63fc6-72c8-4d53-a9b0-e2081026c4f9.

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Staphylococcus aureus is a Gram positive potentially pathogenic bacterium which has a propensity to gather resistance determinants. Mupirocin is a novel topical antibiotic active against many Gram positive species, including staphylococci and effective in the treatment and prevention of staphylococcal infections. Mupirocin acts by competitively inhibiting the charging of isoleucyl tRNA-synthetase (IRS) with isoleucine. Resistance has been observed in Staphylococcus aureus and coagulase negative staphylococci. Intermediate-level resistance (MIC >8μg ml-1 >512μg ml-1) is thought to be due to spontaneous mutations in the native IRS. High-level resistance (>512μg ml-1) is conferred by a second IRS protein, encoded by mupA which has a much lower affinity for mupirocin than isoleucine. The mupirocin resistance gene (mupA) is usually found on a 4.05kb EcoRI fragment of plasmids of otherwise varied EcoRI restriction pattern which are easily transferred between strains by filter mating. Prior to the onset of these studies, mupirocin resistance had not been found linked to another resistance determinant. Initial investigations intended to identify mechanisms of gene flux resident on mupA plasmids revealed a family of related mupA plasmids, the p3356 family which includes three plasmid types: p3356, p3356D and p3358. p3356 contains a single copy mupA flanked by direct repeats of the staphylococcal insertion sequence IS257. p3356D is identical to p3356 except for the duplication of a "mupA-IS257" cassette in tandem repeat. p3358 is related to p3356D by the insertion of a pT181-like plasmid (tetracycline resistant) accompanied by the duplication of an IS257 in direct repeat to flank the inserted pT181; thus p3358 is the first documented example of linked resistance between mupirocin and another resistance determinant, namely tetracycline. IS257 has been implicated as the recombinogenic site in the gene duplication event involved in the evolution of p3356D from p3356. IS257 co-integrative transposition has been demonstrated to allow the co-integration of pOX7 with p3356 to generate a p3358-type plasmid in which pT181 is replaced by pOX7. Therefore, it is concluded that IS257 transposition and recombination is a mechanism by which staphylococcal replicons can evolve to form multiply resistant replicons.
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Nguyen, Thien Ngoc Tran [Verfasser], and Christiane [Akademischer Betreuer] Wolz. "Establishment and evaluation of Staphylococcus aureus strains with integrative reporter-plasmids for detection of cap and agr promoter activity and establishment of a 3D collagen model / Thien Ngoc Tran Nguyen ; Betreuer: Christiane Wolz." Tübingen : Universitätsbibliothek Tübingen, 2018. http://d-nb.info/1168904617/34.

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Browne, C. "Plasmid-chromosomal interactions in Staphylococcus aureus." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355715.

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Evans, Jane E. "The conjugation system of Staphylococcus aureus." Thesis, University of Oxford, 1986. https://ora.ox.ac.uk/objects/uuid:1c1f5c11-f854-4af5-b9cf-34fdf279fb28.

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A conjugation system in Staphylococcus aureus has been investigated and shown to be determined, at least in part, by genes carried on plasmids. Conjugation required cell-to-cell contact but not calcium ions. The frequency of conjugation depended on the recipient used and on the incubation conditions. Two conjugative plasmids were mapped by restriction enzyme analysis but experiments to clone the conjugation-determining region were unsuccessful although separate regions specifying gentamicin resistance, ethidium bromide resistance and cadmium resistance were cloned. The gentamicin resistance determinant was probably part of Tn4001. Deletion of various sized pieces of DNA from one of the plasmids resulted in reduction of its ability to specify conjugation but no specific part of this plasmid could be implicated in the process. Further experiments led to the conclusion that this particular plasmid (p8325-4) is probably not self-transmissible but transferred by a phage-mediated system. Strains of Staphylococcus aureus produced a pheromone-like substance that elicited a clumping response in Streptococcus faecalis but no evidence was found for the involvement of staphylococcal conjugative plasmids in this. The conjugative plasmid, p8325-2, mobilized a small plasmid (pT181) but not a chromosomal gene. Insertion of transposon Tn551 was used to produce mutants of the conjugative plasmid p8325-2. Some twenty-six mutants were studied and the position of Tn551 in them mapped. There were preferred regions of insertion for Tn551 and twenty out of the twenty-six mutants had altered ability to conjugate. One showed a significantly higher frequency of conjugation and the other nineteen, all with substantially lower frequencies of conjugation, were mapped to two well-separated regions of the plasmid. Similarity between the locations of these putative regions and those reported for some other conjugative plasmids from staphylococci is striking and suggests a common origin.
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Balson, Deborah Fiona. "Replication initiation studies of a family of small staphylococcal plasmids." Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/35196.

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pC221 belongs to a family of staphylococcal plasmids, including pT181, pS194, pC223, pUB112 and pCW7 . All possess open reading frames with 70-80% homology to the pC221 rapD gene. REP D has sequence specific topoisomerase activity at the pC221 origin (or iD) which is thought to be involved in replication initiation. DNase I footprinting has been carried out, showing that REP D binds to a region of oriD downstream of the nick site. The pattern of DNase I cleavage suggests that REP D contacts one face of the DNA helix, which may be bent around the protein. Extracts of S. aureus support incorporation of radioactive dNTPs into pC221 in the presence of REP D. Labelling with a[32P] dATP shows that replication initiates within the region containing oriD and proceeds in the direction expected for elongation of a 3' OH generated by nicking at oriD. With supercoiled DNA, REP D initiates replication of other members of this plasmid family in Vitro. However, with relaxed DNA, REP D is specific for oriD, suggesting that a change in the DNA, stabilised by supercoiling of the DNA or by binding of REP D, may be required for nicking. Of three inverted repeat sequences (ICRI, II & III) at the origin, ICRII has the greatest predicted hairpin stability and is almost totally conserved. Nicking takes place within the loop of this proposed hairpin. Disruption of base pairing within this hairpin has been investigated by mutagenesis of cloned oriD and using oligonucleotides based on the ICRII sequence. These experiments show that the 3' side of ICRII is more important for nicking than the 5' side. This is in agreement with footprinting data which shows that REP D binds the 3' side of ICRII, along with the whole of ICRIII. However, there is no evidence for hairpin formation at ICRII being required for nicking.
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Khan, Azra. "An investigation into the association of plasmid-borne qacAB and antimicrobial resistance in meticillin-resistant Staphylococcus aureus." Thesis, University of Portsmouth, 2013. https://researchportal.port.ac.uk/portal/en/theses/an-investigation-into-the-association-of-plasmidborne-qacab-and-antimicrobial-resistance-in-meticillinresistant-staphylococcus-aureus(49b2b0fc-936a-412a-b418-8d9d24d3b531).html.

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Meticillin-resistant Staphylococcus aureus (MRSA) is globally recognised as a major causative organism of hospital acquired infection (HAI) and continues to present many challenges for infection prevention and control. Once established within hospitals and healthcare centers, the control of spread of MRSA and therapy is difficult due to resistance to otherwise effective antimicrobials. Government initiatives in the United Kingdom (UK) have led to considerable investments in improving infection control practices, with emphasis on improving hand hygiene compliance of healthcare professionals and hospital environmental cleanliness to control the spread and limit the source of MRSA and other HAIs. This has resulted in the subsequent increase in disinfectant and antiseptic usage containing, quaternary ammonium compounds (QACs), cationic biocides such as chlorhexidine and the bisphenol ether, triclosan, for decontamination of surfaces and disinfection of skin. Thus, there is serious concern that as with antibiotic resistance, continual and intensive exposure of MRSA (and other hospital pathogens) to biocides, may result in the emergence of resistance to these agents with further detrimental consequences and substantial burden for prevention, treatment and control of hospital infections. MRSA carry a number of plasmid-borne qac genes, predominantly qacA, qacB and smr that encode resistance to commonly used antiseptics and disinfectants in hospitals, nursing homes and other healthcare establishments. The proteins encoded by qacA and qacB mediate efflux via active transport; QacA multidrug exporter mediates resistance to monovalent, divalent cationic and lipophilic antimicrobial compounds, whilst the closely related export protein QacB mediates lower levels of resistance to divalent cations. In this research a “snapshot” study of hospital strains of MRSA stored at the Hospital Infection Research Laboratory (HIRL), City Hospital, Birmingham, was carried out to determine the prevalence and distribution of qacAB in these isolates and determine a possible association between presence of these genes and biocide resistance. The intercalating dye, ethidium bromide (EtBr) is a substrate for many S. aureus multi-drug resistant (MDR) efflux pumps and was used in the present study as a marker for detection of efflux pump activity. Previous studies have reported that MRSA strains with an MIC of ≥ 64 mg/L to EtBr have qacAB, however, the present study used a lower baseline value of ≥ 32 mg/L resistance to EtBr to capture any isolates with low MICs that may have qacAB and may be missed. Initially 3,400 MRSA strains collected between October 2002 and October 2006 were screened to identify and select isolates with ≥ 32 mg/L resistance to EtBr. A second MRSA collection stored at the Antimicrobial Chemotherapy Laboratory, City Hospital, Birmingham, comprised 63 isolates that showed MICs of ≥ 64mg/L, were also included in the study. At this stage the study set (Set A) comprised 112 isolates with varying MIC to EtBr ranging from ≥ 32 mg/L to 256 mg/L. At a later date an additional 400 strains were screened from the same stored collection to include strains with lower MICs, i.e. < 32 mg/L. Thus a total of 336 isolates with varying levels of resistance to EtBr were studied. PCR was carried out on all 336 isolates for detection o qacAB, smr, qacG, qacH and qacJ to determine the presence and prevalence of the genes. Set A isolates positive for qacAB were further investigated to differentiate between qacA and qacB. Restriction digestion using the restriction enzyme Rsa1 was carried out on PCR products followed by PCR using specific primers for detection of the two genes. Urease activity and neomycin sensitivity were used as a means of basic characterization applied to all the study isolates. A select number of samples negative for qacA and qacB were typed using spa typing. Transfer studies involving, conjugation, plate mating and transformation on selected strains were carried out to attempt transfer of qacAB using the marker EtBr from a strain of MRSA with an MIC of ≥ 256 mg/L to EtBr and qacAB positive to a strain with < 32mg/L MIC to EtBr and lacking qacAB. Unfortunately, conjugation experiments were not successful in this study. Plasmid curing experiments were also carried out to demonstrate loss of plasmid through continual passaging onto selective plates. A variety of antiseptics and disinfectants are used in hospitals for prevention of HAIs. The present study was limited to carrying out minimum bactericidal concentration (MBC) determinations and MIC of four commonly used hospital biocides against randomly selected strains. The strains reflected ranges of MICs to EtBr and presence or absence of qacAB. These experiments, determined the efficacy of the biocides tested, to effectively destroy MRSA on skin and environment when used in healthcare settings. The results suggest that in the majority of strains showing high MICs to EtBr i.e. ≥ 64 mg/L, qacAB is present and thus, the mechanism of resistance to biocides may be attributed to an efflux protein pump encoded by these genes. Following restriction digestion of qacAB positive strains, with the restriction enzyme Rsa1, 81 of the 112 qacAB positive strains tested positive for qacA, i.e. 90% and 9 (11%) for qacB. The predominant prevalence of the qacA gene indicates that most of these strains are likely to be resistant to organic cationic biocides and intercalating dyes such as EtBr and acriflavine. However, the results of the MIC and MBC determinations carried out on a selection of biocides commonly used in the healthcare environment implies that the four biocides tested are likely to be 99.9% effective at killing the majority of isolates in this study set. However, five isolates demonstrated MBCs to chlorhexidine of > 32 mg/L. Chlorhexidine is a compound that is widely used in hand hygiene and surgical antisepsis products, and the results suggest that solutions containing this compound would be ineffective in removing MRSA from the hands of healthcare workers and skin sites if used. Molecular spa typing of selected samples negative for qacAB revealed that Endemic-MRSA (EMRSA) type 15 was the most frequent spa type identified in this study, followed by EMRSA-16 and EMRSA-1. Three strains identified jointly as EMRSA-3 and EMRSA-1. One strain identified as the Berlin clone. With regards to the challenges presented to infection prevention and control, MRSA has the potential to develop increased tolerance to biocides commonly used in the hospital environment, due to expression of efflux pumps, although currently there is little evidence of this. Further research is required to understand and learn of the various mechanisms of resistance, supported by adherence to control of infection strategies for prevention and spread of infections in healthcare facilities.
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Morgan, Dale. "Molecular analysis of genes encoding resistance to Cationic Biocides in staphylococci." Curtin University of Technology, School of Pharmacy, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=17463.

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Bacterial resistance to non-antibiotic agents is being increasingly studied. Plasmid-mediated resistance to cationic agents, which are important biocides, has been described in antibiotic-resistant Staphylococcus aureus. Multi-resistant Staphylococcus aureus (MRSA) are often found to express resistance to a range of cationic biocides including quaternary ammonium compounds (QACs), biguanides, diamidino compounds, cationic dyes and nuclear stains. Three resistance determinants, qacA, qacB and smr genes, have been identified that confer resistance to cationic biocides in staphylococci. These genes encode multi-drug efflux pumps that remove the cationic biocides from the cytoplasm using a membrane bound pumping mechanism dependent on the cell's proton-motive force (PMF). This prevents the build up of lethal concentrations of cationic compounds within the cytoplasm avoiding cell death.This research project has focused on the S. aureus strain WBG4364, a transcipient strain carrying the cationic biocide resistant plasmid pWBG1773. The plasmid encodes resistance to several QACs, including benzalkonium chloride and CTAB, and cationic dyes rhodamine 6G, crystal violet and safranin O but not to the dye ethidium bromide and therefore differing from other cationic biocide resistant plasmids previously identified in staphylococci (Emslie et al. 1986). This unique phenotype was further classified in this study alongside those strains carrying the qac gene families, qacA/B and smr.Plasmid pWBG1773 was cloned, sequenced and analysed to reveal a unique plasmid of 2,916 bp in length. Plasmid pWBG1773 was placed with the pC194 family of rolling-circle replicating plasmids. This family appear to be largely composed of interchangeable cassette structures.The plasmid was found to carry three ORFs, designated ORF1, ORF2 and ORF3. ORF1 was homologous to rep genes of small staphylococcal ++
plasmids belonging to the pC194 rolling-circle replication family and has been redefined as repWBG1773. ORF2 was found to have no similarity to any proteins of known function in the GenBank database whereas ORF3 was found to have homology to the marR gene, a regulator of the multiple antibiotic resistance (mar) operon of Gram-negative organisms. MIC analysis of these ORFs found both ORF2 and ORF3 were essential for expression of resistance to cationic biocides. The exact ORF2 sequence required for resistance to be expressed was reduced to only 141 nt in size. This translated to a 47 aa sequence that contained a hydrophobic C-terminus indicating ORF2 to be a membrane-bound protein. The aa sequence of ORF3 contained a helix-turn-helix motif characteristic of the DNA binding domains of MarR-like proteins. Further analysis of pWBG1773 identified a putative 'marbox', a binding site for the homologous transcriptional activators of mar, within the ORF2 sequence. This indicated that ORF3 was binding to the 'marbox' sequence and activating transcription. Induction studies have not been able to ascertain any compounds capable of interacting with the ORF3 regulatory protein resulting in induction of cationic biocide resistance. Each ORF when analysed alone had no effect on the expression of cationic biocide resistance and it is thought that a efflux pump was not involved. This is further corroborated by the CCCP efflux experiments performed in an attempt to determine the mechanism of resistance. The unique ORFs of plasmid pWBG1773 appears to encode a novel cationic biocide resistance phenotype and mechanism.MRSA strains from all around the world were analysed to determine if they possessed sequences homologous to ORF2 and ORF3. Sequences sharing a high degree of homology to ORF2 and/or ORF3 were detected in several MRSA strains including strains sensitive to all cationic ++
biocides tested. These findings suggest that the appearance of ORF2 and ORF3 sequences in MRSAs was not an isolated event and the fact that some MRSAs do not carry both ORF2 and ORF3 sequences simultaneously indicates that these genes have another role that does not involve expression of resistance to cationic biocides.Bacteria are noteworthy for their remarkable ability to adapt to changes in their environments and possess an impressive set of tools with which to adjust the blueprint of the cell to this change. The acquisition of a single system that may decrease a potential pathogenic organisms susceptibility to a wide range of cationic biocides, such as seen in pWBG1773, poses a clinical threat, one that needs to be thoroughly investigated.
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Book chapters on the topic "Staphylococcus aureus plasmids"

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Richmond, M. H., and Joan Johnston. "Genetic Interactions of Penicillinase Plasmids in Staphylococcus aureus." In Ciba Foundation Symposium - Bacterial Episomes and Plasmids, 179–200. Chichester, UK: John Wiley & Sons, Ltd., 2008. http://dx.doi.org/10.1002/9780470715345.ch11.

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Clewell, Don B., Florence Y. An, Bryan A. White, and Cynthia Gawron-Burke. "Sex Pheromones and Plasmid Transfer in Streptococcus Faecalis: A Pheromone, cAM373, Which is Also Excreted by Staphylococcus Aureus." In Plasmids in Bacteria, 489–503. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2447-8_35.

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Berg, Tracey, Neville Firth, and Ronald A. Skurray. "Enterococcal Pheromone-Like Activity Derived from a Lipoprotein Signal Peptide Encoded by a Staphylococcus aureus Plasmid." In Streptococci and the Host, 1041–44. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4899-1825-3_245.

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Mukherjee, Riya, Anjali Priyadarshini, Ramendra Pati Pandey, and Vethakkani Samuel Raj. "Antimicrobial Resistance in Staphylococcus aureus." In Staphylococcus aureus [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96888.

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Staphylococcus aureus is a Gram-Positive bacteria that are responsible to cause skin infections and also shows toxic shock syndrome. Several antibiotics were given against the S. aureus infections but eventually, the prevalence of multidrug resistance of Staphylococcus aureus started emerging. Since then Methicillin-resistant Staphylococcus aureus strains (MRSA)were very common which causes nosocomial infections. Microorganisms for the need of the survival undergoes mutational changes either in their chromosomal DNA/RNA which confers the resistance. One of the famous examples is the resistance against methicillin in Staphylococcus aureus. The evolution of S. aureus is successful in developing multiple resistant strains. Plasmids are capable of carrying the resistant genes and also several toxic genes. In a recent study, it has been observed that drug resistance genes are located in the R plasmids and they are also responsible in conferring multi drug resistance and induce less utilization of multiple antimicrobial therapy. MRSA was not only resistant to methicillin, studies proved MRSA strains were resistant to macrolides, tetracyclines, chloramphenicol. Resistance to vancomycin was very evidently observed, and its transfer among the population and rising of resistant strains was becoming a major threat globally. The resistance of all these antimicrobial agents against the pathogenic microorganisms are taking a rise in some patients due to prolong use of the antimicrobial agents by these patients. The multi drug resistance has enhanced the mortality and morbidity rate which referred to the infecting agents as the “Super Bugs”. Survival of the microorganisms has increased due to the gradual development of extensive resistance against varied antimicrobial drugs. Possible treatments with combinations are found to be the only hope for infections against S. aureus. Few drugs are in development such as Dalbavancin, Oritavancin, Tigecycline. These are the possible treatments upon which the work is going on to reduce the resistance against the invasive MRSA. This chapter highlights the profiles of Staphylococcus aureus and the resistance patterns along with transmission and the role of the plasmid in transmitting the resistance.
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Delpech, Gastón, Leonardo García Allende, and Mónica Sparo. "Mobile Genetic Elements in Vancomycin-Resistant Enterococcus faecium Population." In Pathogenic Bacteria. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.88389.

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Horizontal gene transfer constitutes a key driving force in bacterial evolution. The ability to acquire mobile genetic elements encoding antimicrobial resistance has contributed to the emergence of Enterococcus faecium as one of the main human nosocomial opportunistic pathogens. The deep analysis of the vancomycin-resistant E. faecium (VREfm) population’s mobilome, as the architecture and evolution of the core genome enables to observe VREfm plasticity and power of adaptation in animals, plants, environment and food. The persistence of VREfm is facilitated by the exchange of plasmids, phages and conjugative transposons that have allowed them to achieve a rapid adaptation to changes in environmental conditions. They can acquire resistance determinants from several species and transfer resistance genes to other potentially pathogenic bacteria such as methicillin-resistant Staphylococcus aureus strains.
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Conference papers on the topic "Staphylococcus aureus plasmids"

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Subhi, Hanan, Fatimah Abdel, and Ihsan Raheem. "Isolation of plasmid DNA from Antibiotics Resistant Staphylococcus aureus." In 2018 International Conference on Pure and Applied Science. Koya University, 2018. http://dx.doi.org/10.14500/icpas2018.mim105.

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