Drug resistance of enteric bacteria. V. High frequency of transduction of R factors with bacteriophage epsilon

Reversible translocation of antibiotic resistance determinants in Salmonella ordonez

Salmonella ordonez (BM 2000) codes for kanamycin (Km, aphA), ampicillin (Ap), streptomycin (SmSp:aadA and Sm:aphC), chloramphenicol (Cm), tetracycline (Tc) and sulfonamide (Su) resistances and for production of colicin Ib (Cib). Genetical analysis by incompatibility testing, conjugation, transformation and physical studies using electron microscopy, agarose gel electrophoresis, led us to associate the Km and Cib characters to a 98.7 kilobase (kb) IncI1 plasmid (pIP565), and the Sm (aphC) and Su determinants to a 8.3 kb plasmid (pIP605). The ApCmSmSp(aadA)SuTc determinants were not associated in BM2000 S. ordonez with a plasmid structure. Following conjugation of S. ordonez to E. coli, the ApCmSmSpSuTc determinants were found stably associated with a single plasmid structure (pIP173, 127.5 kb) belonging to IncI1 group. Agarose gel electrophoresis of plasmid DNA restriction endonuclease digests and electron microscopy heteroduplex analysis showed that the acquisition of the ApCmSmSpSuTc determinants resulted from the insertion into pIP565 of a 28.8 kb DNA sequence. This sequence coding for ApCmSmSpSuTu resistances in S. ordonez could be translocated either to pIP565 plasmid or to several IncI1 plasmids but never to plasmids belonging to IncW, IncP or IncFII, suggesting the existence of specific sequences on the IncI1 receptor plasmids. Moreover, R-determinants were translocated back "en bloc" from pIP173 to the chromosome of a susceptible S. ordanez. The results were consistent with the presence in BM2000 S. ordonez chromosomal DNA of an integrated translocatable sequence encoding ApCmSmSpSuTc resistances. Such a structural association could account for the stability of these resistances in the Salmonella ordonez serotype.

Transduction of plasmid determinants in Staphylococcus aureus and Escherichia coli

Buoyant density analysis of transducing lysates derived from Staphylococcus aureus and Escherichia coli indicated that phage particles bearing plasmid determinants contain a quantity of DNA equivalent to that found in the lytic particles. Transducing particles that bear plasmid determinants smaller than viral DNA must therefore contain a quantity of DNA in excess of a single plasmid genome. In the E. coli P1vir system, a dependence upon host-mediated recombination for the transduction of small plasmids, but not for large R factors or chromosomal genes, was observed. However, no evidence for the involvement of such functions in the transduction of S. aureus plasmids was obtained. Although the origin of the additional DNA in plasmid transducing particles has not been identified, circumstantial evidence has been presented in the staphylococcal system indicating that transducing particles carrying a small tetracycline plasmid are not formed by the wrapping of multiple copies of this plasmid DNA.

Isolation of a nontransmissible antibiotic resistance plasmid by transductional shortening of R factor RP1

A plasmid segregant carrying tetracycline and carbenicillin resistance markers has been isolated from R factor RP1 by transductional shortening with phage P22. The new plasmid RP1-S2, which has a molecular weight of 23 times 10-6, has lost the transfer, phage sensitivity, and neomycin resistance functions of RP1. It combines readily with a W group plasmid, R388, to form a transmissible carbenicillin and trimethoprim resistance plasmid, RWP1.

A simple technique for the identification of chain termination suppressor mutants in species of Salmonella

Chain-termination suppressors which are almost certainly amber suppressors have been isolated inSalmonella anatumby a technique involving the use of amber mutants of bacteriophage 01. The same technique could be used in any species ofSalmonella(and many strains of Arizona) and analogous techniques are suggested for use in other genera of bacteria and in higher plants.

Transduction mechanisms of bacteriophage epsilon 15. I. General properties of the system

Bacteriophageεγis capable of transduction both by replacement of a genetic segment of the recipient by the homologous genetic material from the donor strain and by the formation of defective transducing particles capable of lysogenizing the recipient strain ofS. anatum.

The isolation of strains carrying such prophages, which have incorporated the lactose or arabinose operons, is reported. Lysogenic strains, carrying both normal and defective transducing prophage, form high-frequency transducing lysates. Other strains, carrying only defective prophage, show evidence that the association of prophage genes and transduced materials is stable since the loss of one frequently entails loss of the other.

Extrachromosomal inheritance in bacteria

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Phylogenetic relationships of drug-resistance factors and other transmissible bacterial plasmids

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Drug resistance of enteric bacteria. VI. Introduction of bacteriophage P1CM into Salmonella typhi and formation of PldCM and F-CM elements

Kondo, Eiko (Gunma University, Maebashi, Japan), and Susumu Mitsuhashi. Drug resistance of enteric bacteria. VI. Introduction of bacteriophage P1CM into Salmonella typhi and formation of P1dCM and F-CM elements. J. Bacteriol. 91:1787-1794. 1966.-Bacteriophage P1CM was introduced into Salmonella typhi by means of both phage infection and conjugation with Escherichia coli F(+) lysogenic for the phage. Upon incubation with a P1CM phage lysate, S. typhi and S. abony yield CM(r) cells which are lysogenic for P1CM, but S. typhimurium LT2 does not. The P1CM phage is adsorbed slightly to S. typhi, but no infectious centers are formed when the phage is plated on this strain. Tests on P1CM-adsorbing capacity of the S. typhi P1CM(+) strain and on plaque formation and transduction ability of the recovered phage from this strain indicated that the cell and the phage population did not have any special advantage over the original cell and phage population. Conjugation of S. typhi with E. coli F(+) carrying P1CM(+) gave three types of S. typhi CM(r) clones: those which carry the whole P1CM phage, those with the P1dCM element, and those with nontransferable CM(r). The second type has the F factor and is sensitive to f phages in spite of its typical behavior, serologically and biochemically, as S. typhi. It can donate the P1dCM and F(+) characters to E. coli F(-) or F(-)/P1 strains. As a consequence of conjugation with the E. coli F(+) strain, the CM(r) character of the third type of S. typhi, the nontransferable CM(r) element, acquired conjugational transferability, owing to the formation of the element, F-CM. This element can be transferred to an E. coli F(-) strain at a very high frequency (ca. 10(0)). Both the F and CM(r) determinants are jointly transduced with P1 phage and are jointly eliminated by acridine dye treatment.