Identification of pathways required for to colonize alfalfa using TraDIS-.

Unlabelled: Enteropathogenic bacteria, such as , have been linked to numerous fresh produce outbreaks, posing a significant public health threat. The ability of to persist on fresh produce for extended periods is partly attributed to its capacity to form biofilms, which pose a challenge to food decontamination and can increase pathogenic bacterial load in the food chain. Preventing colonization of food products and food processing environments is crucial for reducing the incidence of foodborne outbreaks.

Common food preservatives impose distinct selective pressures on Salmonella Typhimurium planktonic and biofilm populations.

Food preservatives are crucial in controlling microbial growth in processed foods to maintain food safety. Bacterial biofilms pose a threat in the food chain by facilitating persistence on a range of surfaces and food products. Cells in a biofilm are often highly tolerant of antimicrobials and can evolve in response to antimicrobial exposure.

Genomic characterization of Pseudomonas spp. on food: implications for spoilage, antimicrobial resistance and human infection.

Background: Pseudomonas species are common on food, but their contribution to the antimicrobial resistance gene (ARG) burden within food or as a source of clinical infection is unknown. Pseudomonas aeruginosa is an opportunistic pathogen responsible for a wide range of infections and is often hard to treat due to intrinsic and acquired ARGs commonly carried by this species. This study aimed to understand the potential role of Pseudomonas on food as a reservoir of ARGs and to assess the presence of potentially clinically significant Pseudomonas aeruginosa strains on food.

Genome-wide analysis of genes involved in efflux function and regulation within and serovar Typhimurium.

The incidence of multidrug-resistant bacteria is increasing globally, with efflux pumps being a fundamental platform limiting drug access and synergizing with other mechanisms of resistance. Increased expression of efflux pumps is a key feature of most cells that are resistant to multiple antibiotics. Whilst expression of efflux genes can confer benefits, production of complex efflux systems is energetically costly and the expression of efflux is highly regulated, with cells balancing benefits against costs.

Genome-Wide Analysis of Innate Susceptibility Mechanisms of to Colistin.

Colistin is an antibiotic that has seen increasing clinical use for the treatment of human infections caused by Gram-negative pathogens, particularly due to the emergence of multidrug-resistant pathogens. Colistin resistance is also a growing problem and typically results from alterations to lipopolysaccharides mediated by phosphoethanolamine (pETn) transferase enzymes which can be encoded on the chromosome, or plasmids. In this study, we used 'TraDIS-Xpress' (nsposon irected nsertion site equencing with eion), where a high-density transposon mutant library including outward facing promoters in BW25113 identified genes involved in colistin susceptibility.

Comparison of the genetic basis of biofilm formation between Typhimurium and .

Most bacteria can form biofilms, which typically have a life cycle from cells initially attaching to a surface before aggregation and growth produces biomass and an extracellular matrix before finally cells disperse. To maximize fitness at each stage of this life cycle and given the different events taking place within a biofilm, temporal regulation of gene expression is essential. We recently described the genes required for optimal fitness over time during biofilm formation in using a massively parallel transposon mutagenesis approach called TraDIS-.

Massively parallel transposon mutagenesis identifies temporally essential genes for biofilm formation in .

Biofilms complete a life cycle where cells aggregate, grow and produce a structured community before dispersing to colonize new environments. Progression through this life cycle requires temporally controlled gene expression to maximize fitness at each stage. Previous studies have largely focused on identifying genes essential for the formation of a mature biofilm; here, we present an insight into the genes involved at different stages of biofilm formation.

Exposure of Salmonella biofilms to antibiotic concentrations rapidly selects resistance with collateral tradeoffs.

Most bacteria in nature exist in biofilms, which are inherently tolerant to antibiotics. There is currently very limited understanding of how biofilms evolve in response to sub-lethal concentrations of antimicrobials. In this study, we use a biofilm evolution model to study the effects of sub-inhibitory concentrations of three antibiotics on Salmonella Typhimurium biofilms.

Donor plasmids for phenotypically neutral chromosomal gene insertions in .

Recombineering using bacteriophage lambda Red recombinase (λ-Red) uses homologous recombination to manipulate bacterial genomes and is commonly applied to disrupt genes to elucidate their function. This is often followed by the introduction of a wild-type copy of the gene on a plasmid to complement its function. This is often not, however, at a native copy number and the introduction of a chromosomal version of a gene can be a desirable solution to provide wild-type copy expression levels of an allele .

MarA, RamA, and SoxS as Mediators of the Stress Response: Survival at a Cost.

To survive and adapt to changing environments, bacteria have evolved mechanisms to express appropriate genes at appropriate times. Exposure to antimicrobials triggers a global stress response in Enterobacteriaceae, underpinned by activation of a family of transcriptional regulators, including MarA, RamA, and SoxS. These control a program of altered gene expression allowing a rapid and measured response to improve fitness in the presence of toxic drugs.