Pomegranate peel extract reduced colonic damage and bacterial translocation in a mouse model of infectious colitis induced by Citrobacter rodentium.

The pomegranate fruit peel is a rich source of polyphenols including punicalins, punicalagins, and ellagic acids, but is considered an agricultural waste product. Pomegranate derived products have been reported to have a wide variety of health promoting benefits including antibacterial properties in vitro but there is limited evidence of their antibacterial properties in vivo. The purpose of this study was to test the in vivo antibacterial properties of a pomegranate peel extract (PPX) containing punicalin, punicalagin, and ellagic acid.

Pomegranate peel extract alters the microbiome in mice and dysbiosis caused by infection.

Treatment of mice with a pomegranate peel extract (PPX) decreased the pathogenicity of () infections. Here, we investigate the effects of PPX on the microbiome of uninfected or -infected C3H/HeNCr mice by 16S rRNA gene sequencing. Mice were treated with water or PPX for 14 days, feces were collected, and then, the mice were infected with and feces collected again at day 6 postinfection.

Inverted Regulation of Multidrug Efflux Pumps, Acid Resistance, and Porins in Benzoate-Evolved Escherichia coli K-12.

Benzoic acid, a partial uncoupler of the proton motive force (PMF), selects for sensitivity to chloramphenicol and tetracycline during the experimental evolution of K-12. Transcriptomes of isolates evolved with benzoate showed the reversal of benzoate-dependent regulation, including the downregulation of multidrug efflux pump genes, the gene for the Gad acid resistance regulon, the nitrate reductase genes , and the gene for the acid-consuming hydrogenase Hyd-3. However, the benzoate-evolved strains had increased expression of OmpF and other large-hole porins that admit fermentable substrates and antibiotics.

Transcriptomic Analysis of the Swarm Motility Phenotype of Salmonella enterica Serovar Typhimurium Mutant Defective in Periplasmic Glucan Synthesis.

Movement of food-borne pathogens on moist surfaces enables them to migrate towards more favorable niches and facilitate their survival for extended periods of time. Salmonella enterica serovar Typhimurium mutants defective in Osmoregulated periplasmic glucans (OPG) synthesis are unable to exhibit motility on moist surfaces (swarming); however, their mobility in liquid (swim motility) remains unaffected. In order to understand the role of OPG in swarm motility, transcriptomic analysis was performed using cells growing on a moist agar surface.

Swarm motility inhibitory and antioxidant activities of pomegranate peel processed under three drying conditions.

During processing of ready-to-eat fresh fruits, large amounts of peel and seeds are discarded as waste. Pomegranate (Punicagranatum) peels contain high amounts of bioactive compounds which inhibit migration of Salmonella on wet surfaces. The metabolic distribution of bioactives in pomegranate peel, inner membrane, and edible aril portion was investigated under three different drying conditions along with the anti-swarming activity against Citrobacter rodentium.

Acid Evolution of Escherichia coli K-12 Eliminates Amino Acid Decarboxylases and Reregulates Catabolism.

Acid-adapted strains of K-12 W3110 were obtained by serial culture in medium buffered at pH 4.6 (M. M.

Development of an Acid-Resistant Salmonella Typhi Ty21a Attenuated Vector For Improved Oral Vaccine Delivery.

The licensed oral, live-attenuated bacterial vaccine for typhoid fever, Salmonella enterica serovar Typhi strain Ty21a, has also been utilized as a vaccine delivery platform for expression of diverse foreign antigens that stimulate protection against shigellosis, anthrax, plague, or human papilloma virus. However, Ty21a is acid-labile and, for effective oral immunization, stomach acidity has to be either neutralized with buffer or by-passed with Ty21a in an enteric-coated capsule (ECC). Several studies have shown that efficacy is reduced when Ty21a is administered in an ECC versus as a buffered liquid formulation, the former limiting exposure to GI tract lymphoid tissues.

Understanding the host-adapted state of Citrobacter rodentium by transcriptomic analysis.

Citrobacter rodentium (Cr) is a mouse pathogen that mimics many aspects of enteropathogenic Escherichia coli infections including producing attaching and effacing (A/E) lesions. Host-adapted (HA) Cr cells that are shed at the peak of infection have been reported to be hyper-infective. The exact mechanism underlying this phenomenon has remained elusive since the pathogen loses its HA 'status' immediately upon subculturing in laboratory media.

Hypervirulent-host-associated Citrobacter rodentium cells have poor acid tolerance.

Enhanced virulence or infectivity after passage through a mammalian host has been reported for a number of enteric food-borne pathogens. Citrobacter rodentium is a mouse pathogen that mimics many aspects of enterohemorrhagic Escherichia coli infection of humans and serves as a useful model for studying virulence mechanisms. Emergence of a hyperinfectious state after passage through mouse gastrointestinal tract was reported for C.

Role of anionic charges of periplasmic glucans of Shigella flexneri in overcoming detergent stress.

Osmoregulated periplasmic glucans (OPGs) are synthesized by the members of the family Enterobacteriaceae when grown under low osmotic growth conditions. Enteropathogens such as Shigella flexneri spend considerable time outside the host environment such as irrigation waters where low nutrient low osmolarity conditions normally may exist. We recently demonstrated that OPGs of S.

Role of anionic charges of osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium SL1344 in mice virulence.

opgB gene of Salmonella enterica serovar Typhimurium was identified earlier in a genome-wide screen for mice virulence (Valentine et al. in Infect Immun 66:3378-3383, 1998). Although mutation in opgB resulted in avirulent Salmonella strain, how this gene contributes to pathogenesis remains unclear.

Proteomic pleiotropy of OpgGH, an operon necessary for efficient growth of Salmonella enterica serovar typhimurium under low-osmotic conditions.

Salmonella enterica, a bacterial, food-borne pathogen of humans, can contaminate raw fruits and vegetables. Unfortunately for consumers, the bacteria can survive in water used to wash away contaminating bacteria. The ability to survive the low-osmotic conditions of the wash water is attributed to the OpgGH operon that leads to the production of osmotically regulated periplasmic glucans.

Microbial genome analysis and comparisons: Web-based protocols and resources.

Fully annotated genome sequences of many microorganisms are publicly available as a resource. However, in-depth analysis of these genomes using specialized tools is required to derive meaningful information. We describe here the utility of three powerful publicly available genome databases and analysis tools.

Arginine-dependent acid-resistance pathway in Shigella boydii.

Ability to survive the low pH of the human stomach is considered be an important virulent determinant. It was suggested that the unique acid tolerance of Shigella boydii 18 CDPH, the strain implicated in a 1998 outbreak, may have played an important role in surviving the acidic food (bean salad). The strain was capable of inducing arginine-dependent acid-resistance (ADAR) pathway.

Bacteriophage-based rapid and sensitive detection of Escherichia coli O157:H7 isolates from ground beef.

We investigated the efficacy of bacteriophage-based detection technology to detect Escherichia coli O157:H7 from ground beef. The assay involved a short enrichment period of 8 h followed by capture of the pathogen on O157-specific immunomagnetic beads. The captured cells were treated with O157-specific lytic bacteriophage, CSLO157.

Osmoregulated periplasmic glucans synthesis gene family of Shigella flexneri.

Unlabelled: Osmoregulated periplasmic glucans (OPGs) of food- and water-borne enteropathogen Shigella flexneri were characterized. OPGs were composed of 100% glucose with 2-linked glucose as the most abundant residue with terminal glucose, 2-linked and 2,6-linked glucose also present in high quantities. Most dominant backbone polymer chain length was seven glucose residues.

Motility revertants of opgGH mutants of Salmonella enterica serovar Typhimurium remain defective in mice virulence.

We recently demonstrated that osmoregulated periplasmic glucans (OPGs) of Salmonella enterica serovar Typhimurium are required for optimal mouse virulence. However, lack of OPGs also generated pleiotropic phenotypes such as reduced motility and slower growth rate under hypoosmotic growth conditions. Whether the observed suboptimal virulence of opg mutants was due to reduced motility was investigated by isolating fully motile revertants of opgGH mutants.

Osmoregulated periplasmic glucans are needed for competitive growth and biofilm formation by Salmonella enterica serovar Typhimurium in leafy-green vegetable wash waters and colonization in mice.

Osmoregulated periplasmic glucans (OPGs) are major periplasmic constituents of Gram-negative bacteria. The role of OPGs has been postulated in symbiotic as well as pathogenic host-microorganism interactions. Here, we report the role of OPGs from Salmonella enterica serovar Typhimurium during growth and biofilm formation in leafy-green vegetable wash water.

Rapid real-time PCR assay for detecting Salmonella in raw and ready-to-eat meats.

A real-time PCR assay was evaluated for the rapid detection (10 h) of Salmonella in meats using molecular beacon probes available as a commercial kit (iQ-Check, Bio-Rad laboratories). Raw (chicken, pork) and ready-to-eat (RTE) meats were artificially contaminated with Salmonella enterica serovar Typhimurium at the estimated level of 2 to 4 cells per 25 g. After 8 h of pre-enrichment in buffered peptone water, a molecular beacon-based PCR assay was performed to detect contamination in raw and RTE meats.

Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice.

We purified osmoregulated periplasmic glucans (OPGs) from Salmonella enterica serovar Typhimurium and found them to be composed of 100 % glucose with 2-linked glucose as the most abundant residue, with terminal glucose, 2,3-linked and 2,6-linked glucose also present in high quantities. The two structural genes for OPG biosynthesis, opgG and opgH, form a bicistronic operon, and insertion of a kanamycin resistance gene cassette into this operon resulted in a strain devoid of OPGs. The opgGH mutant strain was impaired in motility and growth under low osmolarity conditions.

Characterization of Salmonella isolates from retail foods based on serotyping, pulse field gel electrophoresis, antibiotic resistance and other phenotypic properties.

Sixteen Salmonella strains isolated from a variety of foods during 2000 and 2003 by the Florida State Department of Agriculture were characterized by various genotypic and phenotypic tests. Among 16 isolates, 15 different serotypes were identified. Pulse-field gel electrophoresis (PFGE) fingerprinting profiles obtained using restriction endonucleases XbaI and BlnI revealed that 16 Salmonella isolates were genetically diverse with 16 unique PFGE patterns.

Characterization of Shiga toxin-producing Escherichia coli strains isolated from swine feces.

The virulence gene and antibiotic resistance profiles of Shiga toxin-producing Escherichia coli (STEC) strains belonging to 58 different O:H serotypes (219 strains) isolated from swine feces were determined. Of the 219 isolates, 29 (13%) carried the stx(1) gene, 14 (6%) stx(2), 176 (80%) stx(2e), 46 (21%) estIa, 14 (6.4%) estIb, 10 (4.

Methods and tools for comparative genomics of foodborne pathogens.

A comparison of genome sequences and of encoded proteins with the database of existing annotated sequences is a useful approach to understand the information at the genome level. Here we demonstrate the utility of several DNA and protein sequence comparison tools to interpret the information obtained from several genome projects. Comparisons are presented between closely related strains of Escherichia coli commensal isolates, different isolates of O157:H7, and Shigella spp.

Detection of Salmonella species in foodstuffs.

Conventional methods to detect Salmonella spp. in foodstuffs may take up to 1 wk. Methods for pathogen detection are required.

Role of RNA polymerase sigma-factor (RpoS) in induction of glutamate-dependent acid-resistance of Escherichia albertii under anaerobic conditions.

Escherichia albertii is a potential enteric food-borne pathogen with poorly defined genetic and biochemical properties. Acid resistance is perceived to be an important property of enteric pathogens, enabling them to survive passage through stomach acidity so that they may colonize the mammalian gastrointestinal tract. We analyzed glutamate-dependent acid-resistance pathway (GDAR) in five E.