The pair of DT104 primers, including DT104-F (5′-GTCAGCAGTGTATGGAGCGA-3′) and DT104-R (5′-AGTAGCGCCAGGACTCGTTA-3′), was derived from a specific sequence of 16S-to-23S spacer region of phage type DT104 and its related phage type, U302 (The strains used for PCR positive control were four isolates of serovar Typhimurium DT104 from the Microbiological Diagnostic Unit, University of Melbourne, Melbourne, Australia. Among the serovars that display close relationships (10 regions or fewer that differ between all isolates investigated) are Abortusovis, Agona, Choleraesuis, Oranienburg, Paratyphi C, Senftenberg, Thompson, Typhimurium, and Typhi. The most obvious explanation involves a mechanism by which the surface antigens that define a serovar are transferred to a different genovar, allowing a new genovar to be recruited to the serovar.
Salmonella enterica subspecies enterica serovar 4,[5],12:i:- (S. 4,[5]12:i:-) is believed to be a monophasic variant of S. enterica serovar Typhimurium (S. Typhimurium).
In order to determine whether these clinical isolates resembled any of the serovar Saint Paul ETs that were not represented in the SARB collection, we obtained the genetic profiles of SARA22 and SARA23, representing serovar Saint Paul types Sp1 and Sp2, respectively, as well as the profiles of the Sp3 isolates SARA25 and SARA27 (However, it is possible, if not likely, that isolates of the same MLEE type would belong to different genovars also. The isolates that showed more than three different fragments from pattern U were described as patterns V, W, X, and Y (Table Identification and subtyping of MDR serovar Typhimurium is necessary for understanding and control of the associated infection (This subtyping study of serovar Typhimurium isolates revealed that all of the serovar Typhimurium DT104 strains found were the same clone. There is substantial evidence for the horizontal transfer of genes encoding flagellin and the O antigen within the salmonellae (One way that may allow a better understanding of the method and rate of formation of genovars will be to sequence DNAs from regions of the genome that can shed light on the phylogenetic histories that define serovars in conjunction with regions that distinguish genovars.
It is likely that the host range is determined by a combination of genes in different loci, which can be altered by deletion or simple point mutation events. Subspecies 1 of Salmonella enterica is responsible for almost all Salmonella infections of warm-blooded animals. The isolates of phage type DT104 did not yield the typical MDR pattern as R-type ACSSuT that has been previously reported in many countries (Although the number of serovar Typhimurium DT104 and U302 strains in our study was less than expected, the number of MDR serovar 1,4,[5],12:i:- strains that were duplex PCR positive was high. Moreover, these four isolates had PFGE patterns similar to the pattern of phage type U302. Only a few of these serovars are responsible for most Salmonella infections in humans and domestic animals. In this context, it is interesting that occasionally a particular host-restricted serovar exclusively lacked certain genes that were otherwise present in all strains investigated.
Moreover, additional genes (or phage genomes) and competition between bacterial isolates are also likely to contribute to host range. Even though the phage types of serovar 1,4,5,12:i:- could not be determined because they could not be grouped within specific serovars, it is interesting that 4 of 32 serovar 1,4,5,12:i:- isolates showed the same phage pattern as U302. G-S with agar showed harder texture, and agar/gelatin selection has a significant influence on TPC content in G-S. However, SARA32 and SARA30 only exhibited two differing genomic regions when compared to SARB24 (data not shown).In conclusion, a separate MLEE type generally results in a different genovar. The CT18 prophage present at STY2038-STY2077 was absent from all other isolates, including the serovar Typhi strains investigated.
Among these were only two regions of clustered genes: STM1677 to STM1680 (a thiol peroxidase, an outer membrane protein, a gene similar to the invasin C of The detection of the serovar Typhi CT18 long pathogenicity island SPI7 in serovar Paratyphi C and Dublin isolates has been reported and discussed elsewhere (We were unable to detect specific genes or genomic regions that were absent from all host specialists while being present in host generalists or present in human and absent from nonhuman isolates.