Bacteriophage restriction in Salmonella typhimurium by R factors and transfer factors

Abstract

SUMMARYA 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 f-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 A in this respect predominated among fi-I-like factor from human E9. coli and S. typhimurium and from porcine E. coli. A-like and ColI-like f-factors were equally distributed in bovine S. typhimurium. ColI-like factors were commonest in bovine and avian E. coli.

The problem and implications of chloramphenicol resistance in the typhoid bacillus

“…In animals it is the consequence of the use of antibiotics as feed additives and for the prophylaxis and treatment of disease. Moreover, it is now clear that the R factors in man and animals are drawn from a common pool (Anderson, Threlfall, Carr & Savoy, 1973;Anderson & Threlfall, 1974;Smith, Humphreys & Anderson, 1974;Anderson, Humphreys & Willshaw, in preparation).…”

The use of biochemical fingerprinting, phage typing and antimicrobial-susceptibility testing in the detection of epidemic strains of Salmonella of serotype Typhimurium in Iran

“…24 We have shown already that the frequency of resistance factors for the antibiotics used in this study varied between 20 and 83% among Typhimurium strains from Iran.4 Based on these observation, we postulated that variations observed in PTs or RTs of strains of the same BPT might reflect antibiotic pressure in I~a n .~.~~ Barker et a1., 26 testing 2010 Typhimurium strains isolated from different sources over a 3-year period in Scotland, found that four major phage-type/biotype groups (epidemic strains) accounted for > 50% of their cultures. Our findings, based on combinations of BPT, PT and RT, also demonstrate that most of the Typhimurium strains isolated during 1 year in Iran belonged to a few major BPT/PT/RTs and support the claim of Andersonz7 that, in any country where conditions are favourable for the establishment of salmonellae in man and animals, relatively few clones are responsible for the majority of infections.…”

The characterization of plasmids in the enterobacteria

“…fi-I-like R factors and transfer factors have been divided into eleven types by their typing phage restriction in S. typhimurium (Anderson et al 1973). Further subdivision may be possible by the determination of phage restriction in S. typhi and S. paratyphi B (Anderson, 1966).…”

“…Further subdivision may be possible by the determination of phage restriction in S. typhi and S. paratyphi B (Anderson, 1966). The F factor of K12 restricts one S. typhimurium typing phage (Anderson et al 1973) and unadapted Vi-phages III, V, VI and VII of the S. typhi Vi-typing scheme.…”

“…TP110 KCollb. TP110 converts type 36 of S. typhimurium into type 125, and is a representative of the F group of transfer systems (Anderson et al 1973). This R factor does not alter the Vi-type of S. typhi type A, but restricts the unadapted Vi-phages III, V, VI and VII of that host.…”