Different Shades of : Strain, Serotype, and Lineage-Based Variability in Virulence and Stress Tolerance Profiles.

is a public health and food safety challenge due to its virulence and natural stress resistance phenotypes. The variable distribution of molecular subtypes with respect to food products and processing environments and among human and animal clinical listeriosis cases is observed. Sixty-two clinical and food-associated isolates were examined through phenome and genome analysis.

The Analysis of Field Strains Isolated From Food, Animal and Clinical Sources Uncovers Natural Mutations in Nisin Resistance Genes.

Nisin is a commonly used bacteriocin for controlling spoilage and pathogenic bacteria in food products. Strains possessing high natural nisin resistance that reduce or increase the potency of this bacteriocin against have been described. Our study sought to gather more insights into nisin resistance mechanisms in natural populations by examining a collection of 356 field strains that were isolated from different foods, food production environments, animals and human infections.

Analysis of the Molecular Diversity Among Species Isolated From Filth Flies Using Targeted PCR, Pan Genomic DNA Microarray, and Whole Genome Sequencing Analyses.

species are opportunistic pathogens capable of causing life-threatening infections in humans, with serious complications arising in neonates, infants, immuno-compromised individuals, and elderly adults. The genus is comprised of seven species: , and . Despite a multiplicity of genomic data for the genus, little is known about likely transmission vectors.

Evolution of During a Persistent Human Prosthetic Hip Joint Infection.

associated prosthetic joint infections (PJI) are a rare but increasing clinical problem of listeriosis. We characterized two isolates of the same strain isolated within five years of each other from a recurrent human prosthetic joint infection. The two isolates although clonally identical were phenotypically distinct confirming that the original infection strain had evolved within the human host PJI environment giving rise to a phenotypically distinct variant.

Comparative genomic insights into - a commonly misidentified -like organism.

Food-associated outbreaks linked to enteropathogenic are of concern to public health. Pigs and their meat are recognized risk factors for transmission of . This study aimed to describe the comparative genomics of along with a number of misclassified isolates, now constituting the recently described .

Molecular characterisation of multi-drug resistant Escherichia coli of bovine origin.

Antimicrobial resistance reported in bacteria of animal origin is considered a major challenge to veterinary public health. In this study, the genotypic and phenotypic characterisation of twelve Escherichia coli isolates of bovine origin is reported. Twelve bacterial isolates of animal origin were selected from a previous study based on their multidrug resistant (MDR) profile.

Whole-Genome Sequencing-Based Characterization of 100 Listeria monocytogenes Isolates Collected from Food Processing Environments over a Four-Year Period.

is frequently found in foods and processing facilities, where it can persist, creating concerns for the food industry. Its ability to survive under a wide range of environmental conditions enhances the potential for cross-contamination of the final food products, leading to possible outbreaks of listeriosis. In this study, whole-genome sequencing (WGS) was applied as a tool to characterize and track 100 isolates collected from three food processing environments.

New Insights on the Role of the pLMST6 Plasmid in Biocide Tolerance and Virulence.

the causative agent of listeriosis is an important public health concern and food safety challenge. Increased tolerance of this bacterium to benzalkonium chloride (BC), an antibacterial agent widely used in industrial settings, is a growing issue. Plasmid pLMST6 harboring the gene of the multidrug efflux pump protein EmrC has been recently linked to enhanced BC tolerance and meningitis due to ST6 strains.

Variable Carbon Source Utilization, Stress Resistance, and Virulence Profiles Among Strains Responsible for Listeriosis Outbreaks in Switzerland.

A combination of phenotype microarrays, targeted stress resistance and virulence assays and comparative genome analysis was used to compare a set of strains including those involved in previous Swiss foodborne listeriosis outbreaks. Despite being highly syntenic in gene content these strains showed significant phenotypic variation in utilization of different carbon (C)-sources as well as in resistance of osmotic and pH stress conditions that are relevant to host and food associated environments. An outbreak strain from the 2005 Swiss Tomme cheese listeriosis outbreak (Lm3163) showed the highest versatility in C-sources utilized whereas the strain responsible for the 1983 to 1987 Vacherin Montd'or cheese listeriosis outbreak (LL195) showed the highest tolerance to both osmotic and pH stress conditions among the examined strains.

Atypical Hemolytic Isolates Are Virulent, albeit Less than .

is considered a nonpathogenic species. Natural atypical hemolytic isolates have been reported but have not been characterized in detail. Here, we report the genomic and functional characterization of representative isolates from the two known natural hemolytic clades.

Interaction of matrix metalloproteinase-9 and Zpx in Cronobacter turicensis LMG 23827 mediated infections in the zebrafish model.

Bacteria belonging to the genus Cronobacter have been recognized as causative agents of life-threatening systemic infections primarily in premature and low-birthweight neonates. Validation of putative bacterial virulence components as well as host factors potentially involved in the response to infection has been hampered in the past by the availability of suitable neonatal animal models. In the current study, the zebrafish embryo model was employed to study the interaction of the zinc metalloproteinase Zpx present in Cronobacter turicensis LMG 23827 , with the eukaryotic MMP-9, a proteinase that functions to cleave extracellular matrix gelatin and collagen.

Cold-Shock Domain Family Proteins (Csps) Are Involved in Regulation of Virulence, Cellular Aggregation, and Flagella-Based Motility in .

Cold shock-domain family proteins (Csps) are highly conserved nucleic acid binding proteins regulating the expression of various genes including those involved in stress resistance and virulence in bacteria. We show here that Csps are involved in virulence, cell aggregation and flagella-based extracellular motility of . A mutant deleted in all three genes (Δ) is attenuated with respect to human macrophage infection as well as virulence in a zebrafish infection model.

Comparative Genomic Characterization of the Highly Persistent and Potentially Virulent ST83, CC65 Strain H322 and Other ST83 Strains.

() is an opportunistic pathogen and has been associated with serious infections with high mortality rates predominantly in pre-term, low-birth weight and/or immune compromised neonates and infants. Infections have been epidemiologically linked to consumption of intrinsically and extrinsically contaminated lots of reconstituted powdered infant formula (PIF), thus contamination of such products is a challenging task for the PIF producing industry. We present the draft genome of H322, a highly persistent sequence type (ST) 83, clonal complex (CC) 65, serotype O:7 strain obtained from a batch of non-released contaminated PIF product.

Linking Genomo- and Pathotype: Exploiting the Zebrafish Embryo Model to Investigate the Divergent Virulence Potential among Cronobacter spp.

Bacteria belonging to the genus Cronobacter have been recognized as causative agents of life-threatening systemic infections primarily in premature, low-birth weight and immune-compromised neonates. Apparently not all Cronobacter species are linked to infantile infections and it has been proposed that virulence varies among strains. Whole genome comparisons and in silico analysis have proven to be powerful tools in elucidating potential virulence determinants, the presence/absence of which may explain the differential virulence behaviour of strains.

The DSF type quorum sensing signalling system RpfF/R regulates diverse phenotypes in the opportunistic pathogen Cronobacter.

Several bacterial pathogens produce diffusible signal factor (DSF)-type quorum sensing (QS) signals to control biofilm formation and virulence. Previous work showed that in Burkholderia cenocepacia the RpfFBc/RpfR system is involved in sensing and responding to DSF signals and that this signal/sensor gene pair is highly conserved in several bacterial species including Cronobacter spp. Here we show that C.

Evaluation of zebrafish as a model to study the pathogenesis of the opportunistic pathogen Cronobacter turicensis.

Bacteria belonging to the genus Cronobacter spp. have been recognized as causative agents of life-threatening systemic infections, primarily in premature, low-birth weight and/or immune-compromised neonates. Knowledge remains scarce regarding the underlying molecular mechanisms of disease development.

Influence of FkpA variants on survival and replication of Cronobacter spp. in human macrophages.

Members of the genus Cronobacter are responsible for cases of meningitis and bacteremia with high fatality rates in neonates. Macrophage uptake of invading microbes is an innate process, and it has been proposed that macrophage infectivity potentiator (Mip) like proteins enhance the ability of pathogens to survive within macrophages. Cronobacter harbor the mip-like gene fkpA, but its role in intracellular survival of these bacteria in human macrophages has not yet been studied.