Search PubMed⌕ Search

Biomedical subjects

E S Anderson

Publications and source records attributed to E S Anderson.

At least 55 records · Page 3Linked to original sources
PubMed1973

Bacteriophage restriction in Salmonella typhimurium by R factors and transfer factors.

A total of 2716 R factors and transfer factors isolated from Escherichia coli and salmonellas of human and animal origin were studied for their phage-restrictive effects in Salmonella typhimurium phage type 36. All of 1402 wild fi(+) factors were non-restricting. The F factor of E. coli K12 was unique among the F-like factors tested in that it inhibited lysis of type 36 by one typing phage. In contrast, eleven distinct changes in the phage type of 36 were produced by fi(-) I-like factors. I-like plasmids can thus be subdivided by this method.I-like R factors and transfer factors from human and animal enterobacteria were categorized by their phage-restrictive effects in type 36. Factors resembling Delta in this respect predominated among fi(-) I-like factor from human E. coli and S. typhimurium and from porcine E. coli. Delta-like and ColI-like fi(-) factors were equally distributed in bovine S. typhimurium. ColI-like factors were commonest in bovine and avian E. coli.

Animals↗
PubMed1973

Molecular studies of R factor compatibility groups.

Molecular studies of R factors of six groups, F(II), I(1), I(2), N, B, and H, defined on the basis of compatibility, support the conclusions drawn from genetic studies. In general, R factors of a given compatibility group are similar in size. Deoxyribonucleic acid (DNA) reassociation occurs freely between members of the same group but is minimal between heterologous groups. An exception to this was found in group H, of which one factor showed minimal homology with the remaining plasmids of the group. A further exception was found with groups I(1) and B, which, although genetically distinct, show between 18 and 28% of DNA homology. Groups I(1) and I(2) are molecularly distinct, despite the fact that they both stimulate the synthesis of I-fimbriae.

Centrifugation, Density Gradient↗
PubMed1973

Interactions of group H resistance factors with the F factor.

The four R factors described in this paper form a single compatibility group which has been previously designated group H. Recombination was demonstrated between any pair of the plasmids TP117, 123, and 124. In contrast, TP116 did not appear to recombine with any other members of the group. TP117, 123, and 124 usually displaced the F factor from Escherichia coli K-12F(+), while TP116 and F coexisted stably in that strain. Deoxyribonucleic acid reassociation experiments showed minimal homology between F and the four group H plasmids. The results indicate that there are limitations to using incompatibility alone for classification of bacterial plasmids.

Chloramphenicol↗
PubMed1972

Chloramphenicol resistance in the typhoid bacillus.

Chloramphenicol resistance has been reported in individual strains of Salmonella typhi since 1950, but there had been no accounts of epidemics caused by resistant strains of the organism until 1972, when one occurred in Mexico. Two British patients have been infected in that country, and the organism isolated from them corresponds in all respects with the description of the Mexican epidemic strain of S. typhi: it is a degraded Vi strain resistant to chloramphenicol, streptomycin, sulphonamides, and tetracyclines. It owes its resistance to an R factor which can be transferred to Escherichia coli and thence to drugsensitive S. typhi. Although there is a negligible risk of dissemination of this strain in Britain the incident is a reminder of the need to restrict the use of drugs such as chloramphenicol to the serious diseases for which they are virtually specific.

Chloramphenicol↗