Characterisation of IncI1 plasmids associated with change of phage type in isolates of Salmonella enterica serovar Typhimurium.

Background: Acquisition of IncI1 plasmids by members of the Enterobacteriaceae sometimes leads to transfer of antimicrobial resistance and colicinogeny as well as change of phage type in Salmonella Typhimurium. Isolates of S. Typhimurium from a 2015 outbreak of food poisoning were found to contain an IncI1 plasmid implicated in change of phage type from PT135a to U307 not previously reported.

Genetic characterisation of variants of the virulence plasmid, pSLT, in Salmonella enterica serovar Typhimurium provides evidence of a variety of evolutionary directions consistent with vertical rather than horizontal transmission.

The virulence plasmid pSLT as exemplified by the 94 Kb plasmid in Salmonella Typhimurium strain LT2 is only found in isolates of serovar Typhimurium. While it occurs commonly among such isolates recent genotyping methods have shown that it is mostly confined to certain genotypes. Although pSLT plasmids are capable of self-transmissibility under experimental conditions their confinement to certain host genotypes suggests that in practice they are maintained by vertical rather than by horizontal transmission.

Comparative genomics identifies distinct lineages of S. Enteritidis from Queensland, Australia.

Salmonella enterica is a major cause of gastroenteritis and foodborne illness in Australia where notification rates in the state of Queensland are the highest in the country. S. Enteritidis is among the five most common serotypes reported in Queensland and it is a priority for epidemiological surveillance due to concerns regarding its emergence in Australia.

Comparative genomics of Australian and international isolates of Salmonella Typhimurium: correlation of core genome evolution with CRISPR and prophage profiles.

Salmonella enterica subsp enterica serovar Typhimurium (S. Typhimurium) is a serovar with broad host range. To determine the genomic diversity of S.

Distribution of Gifsy-3 and of variants of ST64B and Gifsy-1 prophages amongst Salmonella enterica Serovar Typhimurium isolates: evidence that combinations of prophages promote clonality.

Salmonella isolates harbour a range of resident prophages which can influence their virulence and ability to compete and survive in their environment. Phage gene profiling of a range of phage types of Salmonella enterica subsp. enterica serovar Typhimurium (S.

Evidence of microevolution of Salmonella Typhimurium during a series of egg-associated outbreaks linked to a single chicken farm.

Background: The bacterium Salmonella enterica serovar Typhimurium (S. Typhimurium) is one of the most frequent causes of foodborne outbreaks of gastroenteritis. Between 2005-2008 a series of S.

Draft Genome Sequences for Ten Salmonella enterica Serovar Typhimurium Phage Type 135 Variants.

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a common cause of gastroenteritis in humans. Here, we report the draft genome sequences of 10 isolates of an S.

A rapid multiplex DNA suspension array method for Salmonella typhimurium subtyping using prophage-related markers.

In this study we developed a preliminary proof of concept of method for Salmonella typhimurium subtyping using multiplex PCR-based phage locus typing and a multiplex Luminex DNA suspension array for product detection. Thirty markers were selected from prophages ST64B, ST64T, ST104, P22, Gifsy-1, sopEΦ and mostly phage-related AFLP fragments, and organised into two multiplex PCRs of 15 markers each. A two-group DNA suspension array was developed using a combination of flow cytometry and Luminex xMAP® technology.

Outbreaks of Salmonella Typhimurium phage type 197 of multiple genotypes linked to an egg producer.

This paper describes outbreaks of Salmonella Typhimurium phage type 197 (STm197) linked to eggs from the farm of a single egg producer. Epidemiological and microbiological investigations (genotyping by multiple locus variable number tandem repeats analysis [MLVA]) identified outbreaks of STm197 with the same or closely-related MLVA profiles in a series of restaurants across Brisbane over 2 months. Environmental health investigations revealed that these restaurants were supplied with eggs from the same egg producer and that cross-contamination may have contributed to the outbreak.

An outbreak of Salmonella enterica serotype Litchfield infection in Australia linked to consumption of contaminated papaya.

An outbreak of 26 cases of Salmonella Litchfield infection occurred in the states of Western Australia and Queensland between October 2006 and January 2007. A case-control study was conducted with 12 cases and 24 controls, and a significant association was found between illness and consumption of papaya (odds ratio, 32.8; 95% confidence interval, 2.

Biosurveillance of emerging biothreats using scalable genotype clustering.

Developments in molecular fingerprinting of pathogens with epidemic potential have offered new opportunities for improving detection and monitoring of biothreats. However, the lack of scalable definitions for infectious disease clustering presents a barrier for effective use and evaluation of new data types for early warning systems. A novel working definition of an outbreak based on temporal and spatial clustering of molecular genotypes is introduced in this paper.