The salmonellae are a diverse group of bacteria within the family Enterobacteriaceae that includes two species, Salmonella enterica and Salmonella bongori. In order to characterize the phylogenetic relationships of the species and subspecies of Salmonella, we analyzed four housekeeping genes, gapA, phoP, mdh and recA, comprising 3,459 bp of nucleotide sequence data for each isolate sequenced. Sixty-one isolates representing the most common serotypes of the seven subspecies of Salmonella enterica and six isolates of Salmonella bongori were included in this study. We present a robust phylogeny of the Salmonella species and subspecies that clearly defines the lineages comprising diphasic and monophasic subspecies. Evidence of intersubspecies lateral gene transfer of the housekeeping gene recA, which has not previously been reported, was obtained.

Salmonellosis is a major cause of gastroenteritis in the United States and can lead to septicaemia, and other extra-intestinal illness including urinary tract infections (UTIs). To examine trends in Salmonella bacteriuria in the United States, surveillance data from the National Salmonella Surveillance System from 1980 to the end of 1999 were reviewed. Overall, 17442 urinary Salmonella isolates were reported, representing 2% of all Salmonella isolates from a known source. This proportion increased from 2% during 1980--1984 to 4% during 1995--1999. The median age of persons from whom these isolates came was 51 years; 12,176 (70 %) were women. Compared to the last national survey conducted between 1968 and 1979, the rate of Salmonella bacteriuria increased among women, from 2.0 per million persons in 1980 to 3.7 in 1999; the highest rate occurring in women > or = 70 years. National reporting of Salmonella bacteriuria increased in absolute incidence and as a proportion of all Salmonella, especially in elderly women and may represent an increase in the incidence of Salmonella UTIs. Better understanding of the uropathogenicity of Salmonella serotypes may further clarify the mechanisms of Salmonella UTIs.

In 2006, Salmonella enterica serovar I 9,12:l,v:- emerged in Bulgaria. The aim of this study was to characterize Salmonella serovar I 9,12:l,v:- isolates from Bulgaria, Denmark, and the United States. We compared isolates of Salmonella I 9,12:l,v:- and diphasic serovars with similar antigenic formulas by pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility. The phase 2 flagellin gene (fljB) was also sequenced for selected isolates. By PFGE, the Salmonella I 9,12:l,v:- isolates from Bulgaria were indistinguishable from the isolate from the United States and distinct from isolates from Denmark; furthermore, several Salmonella I 9,12:l,v:- were indistinguishable from an isolate of Salmonella serovar Goettingen. Sequence analysis showed 100% sequence identity with known H:e,n,z15 sequences of Salmonella Goettingen, which has the antigenic formula I 9,12:l,v:e,n,z15. The study indicated that Salmonella I 9,12:l,v:- is a monophasic variant of Salmonella Goettingen and is present in different countries and on different continents.