Regulation of iron metabolism is critical for the survival of Salmonella Typhimurium in pasteurized milk.

Salmonella is known to survive in raw/pasteurized milk and cause foodborne outbreaks. Lactoferrin, present in milk from all animal sources, is an iron-binding glycoprotein that limits the availability of iron to pathogenic bacteria. Despite the presence of lactoferrins, Salmonella can grow in milk obtained from different animal sources.

Characterization of Strains Originating from Plant-Origin Foods Using Comparative Genomic Analyses and Zebrafish Infectivity Studies.

continues to be isolated from ready-to-eat fresh and frozen produce, flours, dairy powders, cereals, nuts, and spices, in addition to the conventional sources of powdered infant formulae (PIF) and PIF production environments. To understand the sequence diversity, phylogenetic relationship, and virulence of originating from plant-origin foods, comparative molecular and genomic analyses, and zebrafish infection (ZI) studies were applied to 88 strains. Whole genome sequences of the strains were generated for detailed bioinformatic analysis.

'To be, or not to be'-The dilemma of 'silent' antimicrobial resistance genes in bacteria.

Antimicrobial resistance is a serious threat to public health that dramatically undermines our ability to treat bacterial infections. Microorganisms exhibit resistance to different drug classes by acquiring resistance determinants through multiple mechanisms including horizontal gene transfer. The presence of drug resistance genotypes is mostly associated with corresponding phenotypic resistance against the particular antibiotic.

A 16S rRNA Sequencing Study Describing the Environmental Microbiota of Two Powdered Infant Formula Built Facilities.

Microbial safety is critically important for powdered infant formula (PIF) fed to neonates, with under-developed immune systems. The quality and safety of food products are dictated by those microorganisms found in both raw materials and the built production environment. In this study, a 2-year monitoring program of a production environment was carried out in two PIF factories located in the Republic of Ireland, and the environmental microbiome in different care areas of these sites was studied by using a 16S ribosomal RNA (rRNA)-based sequencing technique.

16S rRNA Based Profiling of Bacterial Communities Colonizing Bakery-Production Environments.

Conventional culture-based techniques are largely inadequate in elucidating the microbiota contained in an environment, due to low recovery within a complex bacterial community. This limitation has been mitigated by the use of next-generation sequencing (NGS)-based approaches thereby facilitating the identification and classification of both culturable and uncultivable microorganisms. Amplicon targeted NGS methods, such as 16S ribosomal RNA (16S rRNA) and shotgun metagenomics, are increasingly being applied in various settings such as in food production environments to decipher the microbial consortium therein.

Cow and camel milk-derived whey and casein protein hydrolysates demonstrated effective antifungal properties against selected Candida species.

Bioactive peptides derived from milk proteins are widely known to possess antibacterial activities. Even though the antibacterial effects of milk-derived peptides are widely characterized, not much focus is given to their antifungal characterization. Therefore, in this study, we investigated the antifungal properties of camel and cow whey and casein hydrolysates against various species of pathogenic Candida.

Alterations in the Transcriptional Landscape Allow Differential Desiccation Tolerance in Clinical Cronobacter sakazakii.

Cronobacter sakazakii is a typical example of a xerotolerant bacterium. It is epidemiologically linked to low-moisture foods like powdered infant formula (PIF) and is associated with high fatality rates among neonates. We characterized the xerotolerance in a clinically isolated strain, Cronobacter sakazakii ATCC™29544, and compared the desiccation tolerance with that of an environmental strain, C.

Analysis of the Oxidative Stress Regulon Identifies as a Genetic Target for Resistance Reversal in Multidrug-Resistant Klebsiella pneumoniae.

In bacteria, the defense system deployed to counter oxidative stress is orchestrated by three transcriptional factors, SoxS, SoxR, and OxyR. Although the regulon that these factors control is known in many bacteria, similar data are not available for Klebsiella pneumoniae. To address this data gap, oxidative stress was artificially induced in K.

Silver Nanoparticles Induce a Antibacterial Action Mechanism in Multi-Drug Resistant .

Infections associated with antimicrobial-resistant bacteria now represent a significant threat to human health using conventional therapy, necessitating the development of alternate and more effective antibacterial compounds. Silver nanoparticles (Ag NPs) have been proposed as potential antimicrobial agents to combat infections. A complete understanding of their antimicrobial activity is required before these molecules can be used in therapy.

Draft genome sequences of Oslo isolated from seafood and its laboratory generated auxotrophic mutant.

In recent years, the concept of bacteria-mediated cancer therapy has gained significant attention as an alternative to conventional therapy. The focus has been on non-typhoidal (NTS), particularly Typhimurium, for its anti-cancer properties, however, other NTS serovars such as Oslo, which are associated with foodborne illnesses could potentially be effective anti-cancer agents. Here, we report the draft genome sequence of Oslo isolated from seafood and its laboratory generated auxotrophic mutant.

Exposure to Sub-inhibitory Concentrations of the Chemosensitizer 1-(1-Naphthylmethyl)-Piperazine Creates Membrane Destabilization in Multi-Drug Resistant .

Antimicrobial efflux is one of the important mechanisms causing multi-drug resistance (MDR) in bacteria. Chemosensitizers like 1-(1-naphthylmethyl)-piperazine (NMP) can inhibit an efflux pump and therefore can overcome MDR. However, secondary effects of NMP other than efflux pump inhibition are rarely investigated.

Draft genomes of strains isolated from dried spices bring unique insights into the diversity of plant-associated strains.

is a Gram-negative opportunistic pathogen that causes life- threatening infantile infections, such as meningitis, septicemia, and necrotizing enterocolitis, as well as pneumonia, septicemia, and urinary tract and wound infections in adults. Here, we report 26 draft genome sequences of , which were obtained from dried spices from the USA, the Middle East, China, and the Republic of Korea. The average genome size of the genomes was 4393 kb, with an average of 4055 protein coding genes, and an average genome G + C content of 56.

RNA Sequencing-Based Transcriptional Overview of Xerotolerance in Cronobacter sakazakii SP291.

is a xerotolerant neonatal pathogen epidemiologically linked to powdered infant food formula, often resulting in high mortality rates. Here, we used transcriptome sequencing (RNA-seq) to provide transcriptional insights into the survival of in desiccated conditions. Our RNA-seq data show that about 22% of the total genes were significantly upregulated and 9% were downregulated during desiccation survival.

Increased Virulence of Bloodstream Over Peripheral Isolates of Identified Through Post-transcriptional Regulation of Virulence Factors.

The factors influencing the virulence of in the development of invasive infection remain poorly understood. Here, we investigated the role of the host microenvironment in shaping pathogen virulence and investigated the mechanisms involved. Comparing seven paired genetically indistinguishable clinical bloodstream and peripheral isolates of , we demonstrate that isolates derived from bloodstream infections are more virulent than their peripheral counterparts ( = 0.

A Review on the Applications of Next Generation Sequencing Technologies as Applied to Food-Related Microbiome Studies.

The development of next generation sequencing (NGS) techniques has enabled researchers to study and understand the world of microorganisms from broader and deeper perspectives. The contemporary advances in DNA sequencing technologies have not only enabled finer characterization of bacterial genomes but also provided deeper taxonomic identification of complex microbiomes which in its genomic essence is the combined genetic material of the microorganisms inhabiting an environment, whether the environment be a particular body econiche (e.g.

Multidrug-Resistant Escherichia coli in Bovine Animals, Europe.

Of 150 Escherichia coli strains we cultured from specimens taken from cattle in Europe, 3 had elevated MICs against colistin. We assessed all 3 strains for the presence of the plasmid-mediated mcr-1 gene and identified 1 isolate as mcr-1-positive and co-resistant to β-lactam, florfenicol, and fluoroquinolone antimicrobial compounds.

Flow Cytometric and 16S Sequencing Methodologies for Monitoring the Physiological Status of the Microbiome in Powdered Infant Formula Production.

The aim of this study was to develop appropriate protocols for flow cytometric (FCM) and 16S rDNA sequencing investigation of the microbiome in a powdered infant formula (PIF) production facility. Twenty swabs were collected from each of the three care zones of a PIF production facility and used for preparing composite samples. For FCM studies, the swabs were washed in 200 mL phosphate buffer saline (PBS).

RNA-seq Brings New Insights to the Intra-Macrophage Transcriptome of Salmonella Typhimurium.

Salmonella enterica serovar Typhimurium is arguably the world's best-understood bacterial pathogen. However, crucial details about the genetic programs used by the bacterium to survive and replicate in macrophages have remained obscure because of the challenge of studying gene expression of intracellular pathogens during infection. Here, we report the use of deep sequencing (RNA-seq) to reveal the transcriptional architecture and gene activity of Salmonella during infection of murine macrophages, providing new insights into the strategies used by the pathogen to survive in a bactericidal immune cell.

Hha has a defined regulatory role that is not dependent upon H-NS or StpA.

The Hha family of proteins is involved in the regulation of gene expression in enterobacteria by forming complexes with H-NS-like proteins. Whereas several amino acid residues of both proteins participate in the interaction, some of them play a key role. Residue D48 of Hha protein is essential for the interaction with H-NS, thus the D48N substitution in Hha protein abrogates H-NS/Hha interaction.

Defined single-gene and multi-gene deletion mutant collections in Salmonella enterica sv Typhimurium.

We constructed two collections of targeted single gene deletion (SGD) mutants and two collections of targeted multi-gene deletion (MGD) mutants in Salmonella enterica sv Typhimurium 14028s. The SGD mutant collections contain (1), 3517 mutants in which a single gene is replaced by a cassette containing a kanamycin resistance (KanR) gene oriented in the sense direction (SGD-K), and (2), 3376 mutants with a chloramphenicol resistance gene (CamR) oriented in the antisense direction (SGD-C). A combined total of 3773 individual genes were deleted across these SGD collections.

An infection-relevant transcriptomic compendium for Salmonella enterica Serovar Typhimurium.

Bacterial transcriptional networks consist of hundreds of transcription factors and thousands of promoters. However, the true complexity of transcription in a bacterial pathogen and the effect of the environments encountered during infection remain to be established. We present a simplified approach for global promoter identification in bacteria using RNA-seq-based transcriptomic analyses of 22 distinct infection-relevant environmental conditions.

Serotyping & molecular characterization for study of genetic diversity among seafood associated nontyphoidal Salmonella serovars.

Background & Objectives: Infections due to seafood associated Salmonella serovars are great risk to public health. Different phenotypic characteristics have been used previously for epidemiological investigation of Salmonella. Beyond the phenotypic characterization, a reliable genetic level discriminatory method is required.

sRNAs and the virulence of Salmonella enterica serovar Typhimurium.

The combination of genomics and high-throughput cDNA sequencing technologies has facilitated the identification of many small RNAs (sRNAs) that play a central role in the post-transcriptional gene regulation of Salmonella enterica serovar Typhimurium. To date, most of the functionally characterized sRNAs have been involved in the regulation of processes which are not directly linked to virulence. Just five sRNAs have been found to affect the ability of Salmonella to replicate within mammalian cells, but the precise regulatory mechanisms that are used by sRNAs to control Salmonella pathogenicity at the post-transcriptional level remain to be identified.

Bistability in myo-inositol utilization by Salmonella enterica serovar Typhimurium.

The capability of Salmonella enterica serovar Typhimurium strain 14028 (S. Typhimurium 14028) to utilize myo-inositol (MI) is determined by the genomic island GEI4417/4436 carrying the iol genes that encode enzymes, transporters, and a repressor responsible for the MI catabolic pathway. In contrast to all bacteria investigated thus far, S.