Plasmid profile analysis of a salmonellosis outbreak and identification of a restriction and modification system.
After an outbreak of salmonellosis in humans caused by Salmonella typhimurium bacteriophage type 135, 62 isolates from human, animal, and water sources were retained for further analysis. Most of the isolates (92%) could be placed in one of five plasmid pattern groups, with a majority containing a common 60-kilobase plasmid and a smaller 3.8-kilobase-pair plasmid. This small plasmid, pIMVS1, was labeled with [32P]phosphate and used as a probe in subsequent colony and Southern hybridization studies. We concluded that pIMVS1 from isolates obtained from humans was genetically different from plasmids of a similar size found in isolates from chickens. Studies to characterize pIMVS1 were undertaken to determine if it codes for known virulence factors. It did not appear to be associated with the formation of attachment pili or major outer membrane proteins. By using transposon mutagenesis techniques, Tn3(Apr) was inserted into pIMVS1, and the existence of a restriction and modification system was deduced.
Whiley
S J
SJ
Division of Clinical Microbiology, Institute of Medical and Veterinary Science, Adelaide, Australia.
Lanser
J A
JA
Manning
P A
PA
Murray
C
C
Steele
T W
TW
D000818:Animals; D002645:Chickens; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000032:analysis*; D004196:Disease Outbreaks; D004587:Electrophoresis, Agar Gel; D006801:Humans; D009154:Mutation; D009517:New South Wales; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D012480:Salmonella Infections / Q000453:epidemiology / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity; D014774:Virulence; D014871:Water Microbiology
D004251:DNA Transposable Elements; D004269:DNA, Bacterial