<i>IN VITRO</i> AND <i>IN VIVO</i> METHODOLOGY FOR DETECTING AND EVALUATING INHIBITORS OF TRANSFER OF RESISTANCE FACTORS

Ott, J. L.; Short, Lois J.; Holmes, D. H.

doi:10.1111/j.1749-6632.1971.tb30667.x

Cited by 10 publications

(10 citation statements)

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“…In experiments g and h, corresponding to c and d, an opposite situation occurred: the transconjugants re-330 SANSONETTI ET AL. enic animals (22,23,31,35,36,47). The results were very reproducible from one experiment to another and from one animal to another.…”

Section: Downloaded Fromsupporting

confidence: 51%

“…Experiments involving germfree animals contaminated by a donor and a recipient population show the existence of an important plasmid transfer (22,23,31,35,36,47). This artificial system is a means of simplifying experimental models and allowing the comparison of experimental results to theoretical models such as those of Anderson and Lustbader (5) or Stewart and Levin (46).…”

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confidence: 99%

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Parameters controlling interbacterial plasmid spreading in a gnotoxenic chicken gut system: influence of plasmid and bacterial mutations

Sansonetti¹,

Lafont²,

Jaffé-Brachet³

et al. 1980

Antimicrob Agents Chemother

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Conjugative transfer of R plasmids R64 and R64drd-11 has been compared in vitro and in vivo without selective pressure by antibiotics in a simplified experimental system; the ecosystem was the bowel of germfree chickens, with the host bacteria almost isogenic, and the plasmids differing only in their conjugative transfer frequency. The spread of repressed and derepressed (drd) R plasmids in recipient bacterial populations was very extensive. The repressed phenotype had only a transient effect during the first 4 h. The level of implantation of the donor bacterial population seems to be of minor importance. Only with a poor recipient (con strain) could the spread of R plasmids be reduced and a steady state with a predominantly sensitive bacterial population be established. It is suggested that this steady state results from an equilibrium between the frequencies of R plasmid transfer and loss.Conjugative transfer is a frequent property of enterobacterial plasmids in general and R plasmids in particular. This complex and multigenic mechanism has been observed in the laboratory (in vitro) and seems to exist also in nature, particularly in the gut of animals and humans (in vivo) (13).The intestinal ecosystem of monogastric animals is complex and open (37). Their procaryotic floras are extremely dense and include, among the major groups of microorganisms, strictly anaerobic species (10'0/g of feces) and Enterobacteriaceae (106 to 108/g of feces). The variety of species, mixing, and high bacterial density may be favorable conditions for conjugative transfer. But it is difficult to quantify in vivo transfer, and little is known about the major parameters controlling its occurrence.Epidemiological studies on antibiotic resistance in bacteria (7,9,12,14,28,39,48) and direct data obtained from contaminated humans (1,4,6,32,33,40,42,50) or animals (13,16,17,21,34,41,43,44) give evidence of an in vivo transfer with or without antibiotic selective pressure. A higher proportion of transconjugants is usually obtained in the presence of selective antibiotics (3, 4).Experiments involving germfree animals contaminated by a donor and a recipient population show the existence of an important plasmid transfer (22,23,31,35,36,47). This artificial system is a means of simplifying experimental models and allowing the comparison of experimental results to theoretical models such as those of Anderson and Lustbader (5) or Stewart and Levin (46). These authors have considered three important parameters: the growth rate, the conjugative transfer frequency, and the plasmid rate of loss through segregation. Their model is restrictive because the plasmids are not bacteriocinogenic and are independent of the chromosome, and because plasmid maintenance is not imposed by selective pressure.We have applied the same restrictive conditions to a qualitative and quantitative study of in vivo conjugative transfer in a simplified experimental model. The ecosystem was the germfree chicken gut. The contaminating strains used were derived from the same pare...

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confidence: 51%

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confidence: 99%

Parameters controlling interbacterial plasmid spreading in a gnotoxenic chicken gut system: influence of plasmid and bacterial mutations

Sansonetti¹,

Lafont²,

Jaffé-Brachet³

et al. 1980

Antimicrob Agents Chemother

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“…4). Similar growth was otics, semi-synthetic penicillins, 3'-deoxy kanamycin (13); (iii) drugs interfering in the resistance transfer process; drugs restoring activity at the episomal level (3,5,6); and drugs inhibiting some metabolic processes necessary for the transfer of resistance factors (7,10,11). In addition to these research programs, development of substances which act on enzymes that inactivate antibiotics must be considered to be an effective approach for control of antibioticresistant strains.…”

Section: Resultsmentioning

confidence: 99%

Screening and Isolation of Penicillinase Inhibitor, KA-107

Iwai

Ohno

Tanaka

et al. 1973

Antimicrob Agents Chemother

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It is known that penicillin resistance of bacteria is mainly caused by the inactivation of penicillin by penicillinase derived from such strains. We have developed a screening procedure for penicillinase inhibitors. Several microorganisms were found to produce such inhibitors, and from the culture filtrate of Streptomyces gedanensis ATCC 4880 a penicillinase inhibitor, named KA-107, was isolated. The characteristics of this inhibitor were revealed by an in vitro test by using penicillinase derived from penicillin resistant Staphylococcus aureus , FS-1277. When KA-107 was used in combination with penicillin-G, ampicillin, d - or l -phenethicillin, the growth inhibitory activity of these penicillins was maintained.

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“…Some mutagens, several DNA complexing Table 2 The agents which stimulate plasmid curing, or inhibit the production of transconjugants, in Gram-negative bacteria by affecting the cell envelope or by inhibiting the synthesis of DNA or proteins Table 2). These agents also include inhibitors of the DNA-dependent RNA synthesis, such as rifampicin, actinomycin D [75,80], and distamycin A [87], which may, at least at higher concentrations, inhibit the priming of DNA replication as well [88]. The other inhibitors of conjugal transfer which affect the early stages of replication include phenethyl alcohol [74] and comafine and quinolone antibiotics [34,89].…”

Section: Agents Which Interact With Dnamentioning

confidence: 99%

“…Furthermore, some aminoglycosides, e.g. gentamycin and kanamycin, which inhibit Rplasmid transfer in E. coli [75], enhance the permeability in the OM in Pseudomonas aeraginosa [50,98,991. Basic peptide antibiotics of the polymyxin group and their synthetic derivatives bind to the acidic molecules of the OM of Gram-negative bacteria [99,100]. This results in enhancement in the permeability of the OM and is assumed to be the primary event of drug action [50,99,102].…”

Section: Agents Which Affect Membrane Permeabilitymentioning

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The susceptibility of conjugative resistance transfer in Gram-negative bacteria to physicochemical and biochemical agents

Viljanen

Boratyński

1991

FEMS Microbiology Letters

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Over thirty years of studies have established that conjugative transfer of plasmid‐encoded resistance to drugs and heavy metals can take place at high frequency between various organisms under laboratory conditions. The detected transfer frequencies in soil, in aquatic environments, and in the urogenital and respiratory tracts of healthy animals and man have generally been low. However, the conversion of bacteria from susceptible to resistant to antibiotics has been observed often during antimicrobial therapy. This has formed a challenge for the antibacterial treatment of pathogenic bacteria and called for the evaluation of the extent of conjugative transfer in various environments. Several biochemical and physicochemical factors inhibit conjugation, show preferential toxicity against plasmid‐bearing cells, or stimulate plasmid curing. These factors include various agents such as detergents, anesthetics, mutagens and antibiotics which affect membrane potential, membrane permeability, protein synthesis and the processing of DNA. The application of the data on these agents, summarized in this review, might be helpful in preventing drug multi‐resistance from spreading. Also these data might be valuable in studies which use conjugation as a tool or which treat the molecular mechanisms involved in conjugation.

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IN VITRO AND IN VIVO METHODOLOGY FOR DETECTING AND EVALUATING INHIBITORS OF TRANSFER OF RESISTANCE FACTORS

Cited by 10 publications

References 9 publications

Parameters controlling interbacterial plasmid spreading in a gnotoxenic chicken gut system: influence of plasmid and bacterial mutations

Parameters controlling interbacterial plasmid spreading in a gnotoxenic chicken gut system: influence of plasmid and bacterial mutations

Screening and Isolation of Penicillinase Inhibitor, KA-107

The susceptibility of conjugative resistance transfer in Gram-negative bacteria to physicochemical and biochemical agents

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