Molecular characterization of the serotype-associated plasmids of Salmonella enterica

• Main Author: Browning, Lynda M.
• Format: Thesis
• Language: English
• Published: 1996
• Subjects: Antarc*; Antarctica
• Online Access: http://theses.gla.ac.uk/38948/; https://theses.gla.ac.uk/38948/1/1996Browning%20PhD.pdf; https://eleanor.lib.gla.ac.uk/record=b1636467

The clinical importance of Salmonella has been known for more than a century. The control of salmonellosis requires detailed understanding of both pathogenicity and epidemiology. Certain plasmids are involved in the virulence of the salmonellae and their analysis often contributes to epidemiological investigation. Molecular characterization of the serotype associated plasmids of the salmonellae was undertaken. A predefined strategy of restriction endonuclease fragmentation pattern (REFP) analysis revealed plasmids previously defined as "serotype specific" were present in different serotypes. Plasmids indistinguishable from of molecular variants of established serotype associated plasmids (SAP's) were detected in other serotypes of serogroup Dl. The results showed that related or identical plasmids were present in both strains which varied only slightly in their H antigens e.g. Enteritidis (gm), Moscow (gq) and Blegdam (gmq) as well as a strain of Antarctica which possessed the H antigens gz63,. In addition to plasmid similarity within a serogroup, plasmids were identified in strains of Wangata which although a member of serogroup D are outwith the g-complex of flagellar antigens (H = Z4Z23). Unexpectedly, these plasmids were closely related to Typhimurium which belongs to serogroup B. The incompatibility of the plasmids was tested with a cointegrate plasmid pOG669 (a cointegrate of pOG660, the Typhimurium plasmid and pOG670, an IncX R-plasmid) and confirmation of incompatibility to the Typhimiuium component of this plasmid was shown by introduction and compatibility with pOG670. Plasmid incompatibility analysis of these plasmids revealed all the SAP's, Except Dublin, were incompatible with Typhimurium and confirmed a family of related plasmids common to but not restricted in their distribution to individual serotypes. Co-resident plasmids of intermediate size (30 - 40 kb) were observed relatively frequently in certain serotypes of GpD1- notably Dublin, Enteritidis, Moscow, Blegdam and Antarctica. With the ...