R-factor Mediated Resistance to Penicillins which does not Involve a  -Lactamase

Curtis, Nigel A. C.; Richmond, M. H.; Stanisich, Vilma A.

doi:10.1099/00221287-79-1-163

Cited by 32 publications

(16 citation statements)

References 12 publications

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“…The presence of genes on these plasmids which affected the intrinsic resistance of bacteria was confirmed by the isolation of mutant R-factors in which the ,-lactamase gene had been deleted (1). This paper extends preliminary studies and describes some of the changes in surface properties that R-factors induce in bacteria carrying them.…”

supporting

confidence: 52%

Effect of R-Factor-Mediated Genes on Some Surface Properties of Escherichia coli

Curtis

Richmond

1974

Antimicrob Agents Chemother

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The plasmid RP1 was shown to contain a genetic region (the irp region) responsible for influencing the intrinsic resistance of Escherichia coli to penicillins but not to cephalosporins. Mutants in whic"h the irp genes are inactive were isolated. RP1 carrying functional irp genes protected E. coli AS19 against lysozyme lysis and also enhanced resistance to actinomycin D, to nalidixic acid, and to rifampin. This plasmid also phenotypically repaired the hypersensitivity to penicillins of strain AS19, and also that of E. coli envA mutants. Similar regions were not detected on the plasmids Rl and R55.

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supporting

confidence: 52%

Effect of R-Factor-Mediated Genes on Some Surface Properties of Escherichia coli

Curtis

Richmond

1974

Antimicrob Agents Chemother

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“…It is known that a variety of mechanisms such as enzymatic inactivation, permeability barrier, irreversible binding to a strategically placed enzyme including f1-lactamases (trapping of antibiotics), and alteration of the target site of antibiotics are involved in bacterial resistance to f1-lactam antibiotics (2,4,12,14,(19)(20)(21). It is true that enzymatic inactivation and hydrolysis by f1-lactamases play the leading role in the drug-resistance mechanisms.…”

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confidence: 99%

A Possible Role of R Plasmids in Bacterial Permeability for β‐Lactam Antibiotics

Ikeuchi

Osada

1981

Microbiology and Immunology

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Four strains of clinical isolates of Serratia marcescens (13039, 13090, 13093, 14093) harboring R plasmids were highly resistant to ampicillin (ABPC) and cephaloridine (CER). With elimination of R plasmids from these strains by acriflavine treatment, ABPC-resistance levels of these strains were markedly reduced. Reduction of CER-resistance levels was also demonstrated in strains 13039 and 13093, but not in strains 13090 and 14093. The permeability of the former strains for CER was also decreased, but not in the latter strains. At the same time, fllactamase activity of these strains also almost completely disappeared when the R plasmids were eliminated. By broth matings with these strains, the recipient strains of S. marcescens 13031 (rif), Escherichia coli K-12 (rif), and E. coli 15046 (rif) all acquired a high permeability barrier against CER with inheritance of the R plasmids from strains 13039 and 13093, but not from strains 13090 and 14093. The transconjugant of strain 13031 that inherited R plasmid 13093 was resistant not only to CER but also to cefazolin, cephalothin, and cephalexin. Its permeabiiity to these antibiotics was significantly lower than that of the original strain. This fact suggests the possibility that the R plasmid from strain 13093 may be involved not only in production of p-lactamases, but also in regulation of bacterial permeability for cephalosporins.

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“…The plasmid phenotypes were the same in P~X G N as in CB-I, confirming that mutations were carried on the plasmid. The phenotype of the As mutant was interesting in that sensitivity to ampicillin was not completely lost; in this respect the mutant resembles that described by Curtis, Richmond & Stanisich (1973). The As isolate, when plated on MacConkey agar containing ampicillin at 10, 25, and 5 0 p g rnl-l?…”

Section: -2 428mentioning

confidence: 61%

Isolation of Amber Mutant of a P Group R Factor after Hydroxylamine Mutagenesis of a Transducing Lysate

Baumberg

1976

Journal of General Microbiology

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R-factor Mediated Resistance to Penicillins which does not Involve a -Lactamase

Cited by 32 publications

References 12 publications

Effect of R-Factor-Mediated Genes on Some Surface Properties of Escherichia coli

Effect of R-Factor-Mediated Genes on Some Surface Properties of Escherichia coli

A Possible Role of R Plasmids in Bacterial Permeability for β‐Lactam Antibiotics

Isolation of Amber Mutant of a P Group R Factor after Hydroxylamine Mutagenesis of a Transducing Lysate

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