REGULATION OF R‐FACTOR REPLICATION IN <i>ROTEUS MIRABILIS</i>*

Kopecko, Dennis J.; Punch, J. D.

doi:10.1111/j.1749-6632.1971.tb30657.x

Cited by 22 publications

(20 citation statements)

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“…Moreover, certain R factors are formed by reversible covalent linkage of separate plasmids that independently harbor either resistance or transfer functions (4)(5)(6)(7)(8)(9). Recent electron microscope studies of heteroduplex formation between the DNA of various R factors, and between DNA of R factors and certain other bacterial plasmids, have indicated that these earlier conclusions about-the molecular nature and structural composition of R factors are correct (ref.…”

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confidence: 84%

“…Biochemical and genetic investigations in several different laboratories (1)(2)(3)(4)(5)(6)(7)(8)(9) have established that antibiotic resistance factors (R factors) of the Enterobacteriacae consist of autononwusly replicating units of extrachromosomal DNA. Moreover, certain R factors are formed by reversible covalent linkage of separate plasmids that independently harbor either resistance or transfer functions (4)(5)(6)(7)(8)(9).…”

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confidence: 99%

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Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of Escherichia coli by R-Factor DNA

Cohen

Chang

Hsu

1972

Proc. Natl. Acad. Sci. U.S.A.

2,277

805

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Transformation of E. coli cells treated with CaCJ2 to multiple antibiotic resistance by purified R-factor DNA is reported. Drug resistance is expressed in a small fraction of the recipient bacterial population almost immediately after uptake of DNA, but full genetic expression of resistance requires subsequent incubation in drugfree medium before antibiotic challenge. MATERIALS AND METHODSBacterial Strains and R Factors. The I-like R factor, R64-11 (16), which specifies resistance to tetracycline (Tc) and streptomycin (Sm), was obtained from R. Curtiss. R6 (17), an F-like R factor that carries resistance to kanamycin (Km), neomycin (Nm), chloramphenicol (Cm), sulphonamide (Su), streptomycin, and tetracycline, was obtained from T. Watanabe. R6-5, a spontaneous variant of R6 that lacks tetracycline resistance, was isolated in our laboratory (18). The bacterial strains used in these experiments have been described (7,22). DNA Preparations. In certain instances, covalently-closed R-factor DNA was isolated and purified from E. coli as described (6, 7). Alternatively, a Brij-lysis procedure (19) was used for initial R-factor DNA isolation, and preparations obtained by this method were subsequently purified by centrifugation in cesium chloride-ethidium bromide gradients. The catenated, closed circular, and noncircular forms of R-factor DNA used in experiments comparing the relative transforming ability of the various R-factor DNA species were isolated from E. coli minicells. R-factor DNA was denatured by heating it at 980 for 5 min in 15 mM NaCl-1.5 mM Na citrate followed by rapid cooling at 0°. Sonication of R-factor DNA to about 9S fragments was done for 15 see at 00 by a Branson model W185 D sonicator, and the size of the R-factor DNA fragments was confirmed by sucrose gradient centrifugation (7).Transformation Reaction Mixture. Transformation was done by a variation of the procedure of Mandel and Higa (15), as modified by Lobban, Masuda, and Kaiser (personal communication). E. coli strain C600 was grown at 370 in H1 medium (20) to an optical density of 0.85 at 590 nm. At this point, the cells 2110 Abbreviation: R factor, antibiotic resistance factor. * The previous paper in this series is ref. 18.

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Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of Escherichia coli by R-Factor DNA

Cohen

Chang

Hsu

1972

Proc. Natl. Acad. Sci. U.S.A.

2,277

805

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“…The extensive antimicrobial susceptibility to Gatifloxacin in the current study may be due to their infrequent use in veterinary practice. The use of most fluoroquinolones (ciprofloxacin) and the aminoglycosides (streptomycin) in majority of cases even without confirmatory diagnosis of cause could be one possible reason behind rapidly developing resistance against the drugs of these classes (Kopecko and Punch, 1971;Williamson, 1983;von Baum and Marre, 2005;Ewers et al, 2012;Escobar et al, 2013). Irrational and indiscriminate use of antibiotic drugs led to unresponsiveness of microbial agents or developing resistance of bacterial strains against various drugs.…”

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confidence: 99%

Bacterial Etiology of Skin and Wound Infections along with Antibiogram Profiling in Reference to Emerging Antibiotic Resistance in Animals

Tiwari¹,

Yadav²,

Singh³

et al. 2015

Adv. Anim. Vet. Sci.

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| The present study demonstrated bacterial etiology of skin affections and their antibiogram profiling of different animal species of various age groups. A total of 255 samples from cattle, buffalo, dogs, goats, sheep, camel and horses were collected over a period of two years (2012)(2013)(2014) from Mathura, (U.P.) India, and nearby surrounding areas. Clinical samples were collected from variety of skin disorders, subjected to laboratory isolation and identification as per standard protocols. The bacterial infection, Staphylococcus aureus, was the most common isolate (36.22 %), followed by E. coli (34.59 %), Pseudomonas (20.54), Bacillus (16.21), Klebsiella (12.43), Micrococcus spp (8.11 %), Streptococcus pyogens (7.56), Proteus (6.49), Clostridium (3.78), Gram negative non-lactose fermenter (2.7%), Gram positive non-spore producing bacilli (2.16) and Fusobacterium (0.54 %). Bacterial isolates obtained were subjected to in vitro antibiotic sensitivity testing by disc diffusion method against 23 commercially available antimicrobial discs. Results of the current study revealed maximum sensitivity to gatifloxacin (94.03%), amikacin (85.7%), mild sensitivity to sparfloxacin (44.85%) and gentamicin (43.48%); emergence of multi-drug resistant bacterial strains of Staphylococcus aureus, Pseudomonas aeruginosa, E.coli appeared to be an important finding. Present study is intended to document the complex microbial inhabitants of wounds from animals and their antimicrobial sensitivity pattern and strongly recommended the use of antimicrobial sensitivity testing to know the rapidly changing pattern of antibiotic activity. The study will further aid to the existing literature for planning new alternative therapeutic strategies against rising global health havoc of multidrug resistance.

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“…Earlier investigations of the molecular nature of non-chromosomal drug resistance factors (R factors) of the Enterobacteriaceae indicate that certain R factors are formed by covalent linkage of plasmids that separately carry resistance or transfer functions (12,34,38,42). The R factors comprising this group have been designated "class 1" by Anderson (4) and "plasmid co-integrates" by Clowes (7); although they exist largely as a single replicon in Escherichia coli, members of this class are commonly able to dissociate into component transfer (RTF) and resistance determinant (R determinant) plasmids in Proteus (11,12,22,28,34,38). It has I Present address: Rijks Institut voor de Volksgezondheid Bilthoven, Holland. been suggested that class 1 R factors may contain only a single replicator site which can segregate with either the RTF or R-determinant component of the plasmid when these two units dissociate (45).…”

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Molecular and Genetic Studies of an R Factor System Consisting of Independent Transfer and Drug Resistance Plasmids

Embden

Cohen

1973

J Bacteriol

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Certain genetic, structural, and biochemical properties of a class 2 R-factor system consisting of the conjugally proficient transfer plasmid I and the naturally occurring non-conjugative tetracycline (Tc) resistance plasmid 219 are reported. I and 219 exist as separate plasmid deoxyribonucleic acid (DNA) species in both Escherichia coli and Salmonella panama, having molecular weights of 42 x 106 Genetic experiments by Anderson and his collaborators (2, 3), Guinee and Williams (21), and Krcmery et al. (29) have indicated the existence of another general class of R factors. 699 on July 31, 2020 by guest

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REGULATION OF R‐FACTOR REPLICATION IN *ROTEUS MIRABILIS**

Cited by 22 publications

References 23 publications

Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of Escherichia coli by R-Factor DNA

Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of Escherichia coli by R-Factor DNA

Bacterial Etiology of Skin and Wound Infections along with Antibiogram Profiling in Reference to Emerging Antibiotic Resistance in Animals

Molecular and Genetic Studies of an R Factor System Consisting of Independent Transfer and Drug Resistance Plasmids

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REGULATION OF R‐FACTOR REPLICATION IN ROTEUS MIRABILIS*

Cited by 22 publications

References 23 publications

Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of Escherichia coli by R-Factor DNA

Nonchromosomal Antibiotic Resistance in Bacteria: Genetic Transformation of Escherichia coli by R-Factor DNA

Bacterial Etiology of Skin and Wound Infections along with Antibiogram Profiling in Reference to Emerging Antibiotic Resistance in Animals

Molecular and Genetic Studies of an R Factor System Consisting of Independent Transfer and Drug Resistance Plasmids

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REGULATION OF R‐FACTOR REPLICATION IN *ROTEUS MIRABILIS**