Research Publications (Food Safety)

Abstract

Few studies within the pathogenic field have used advanced imaging and analytical tools to quantitatively measure pathogenicity in vivo. In this work, we present a novel approach for the investigation of host–pathogen processes based on medium-throughput 3D fluorescence imaging. The guinea pig model for Shigella flexneri invasion of the colonic...

The class-II AP-endonuclease (XthA) acts on abasic sites of damaged DNA in bacterial base excision repair. We identified that the sliding DNA β-clamp forms in vivo and in vitro complexes with XthA in Mycobacterium tuberculosis. A novel 239QLRFPKK245 motif in the DNA-binding domain of XthA was found to be important for the interactions. Likewise, the peptide-binding-groove (PBG) and the C-terminal of β-clamp located on different domains, interact with XthA.

Publication date: 1 October 2015
, Volume 210
Author(s): Seonyeong Choi , Sunhyung Park , Yoonsook Kim , Byeong-sam Kim , Larry R. Beuchat , Kim Hoikyung , Jee-Hoon Ryu

Aims
The aim of this study was to study inactivation of different pathogenic bacteria on agar model surface using TiO2-UV photocatalysis (TUVP).

Siderophores, small iron-binding molecules secreted by many microbial species, capture environmental iron for transport back into the cell. Vibrio cholerae synthesizes and uses the catechol siderophore vibriobactin and also uses siderophores secreted by other species, including enterobactin produced by Escherichia coli. E. coli secretes both canonical cyclic enterobactin and also linear enterobactin derivatives likely derived from its cleavage by the enterobactin esterase Fes.

In Salmonella enterica the thiamine biosynthetic intermediate 5-aminoimidazole ribonucleotide (AIR) can be synthesized de novo independent of the early purine biosynthetic reactions. This secondary route to AIR synthesis was dependent on i) amino-4-imidazolecarboxamide ribotide (AICAR) accumulation, ii) a functional phosphoribosylaminoimidazole-succinocarboxamide (SAICAR) synthetase (PurC, EC 6.3.2.6), and iii) methionine and lysine in the growth medium.

Salmonella enteric serovar Typhimurium (S. Typhimurium), a major cause of food-borne illness, is capable of using a variety of carbon and nitrogen sources. Fructoselysine and glucoselysine are Maillard reaction products formed by the reaction of glucose or fructose, respectively, with the -amine group of lysine. We report here that S.

Publication date: October 2015
, Volume 51
Author(s): Ana Graça , David Santo , Eduardo Esteves , Carla Nunes , Maribel Abadias , Célia Quintas

Aims
Using molecular subtyping techniques, Listeria monocytogenes is divided into three major phylogenetic lineages, and a multiplex PCR method can differentiate five L. monocytogenes subgroups: 1/2a-3a, 1/2c-3c, 1/2b-3b-7, 4b-4d-4e, and 4a-4c. In the current study, we conducted genome comparisons and evaluated serotype-associated genes for their utility as a multiplex PCR-based method for distinguishing high-risk serotypes 1/2a and 1/2c in lineage I from low-risk serotypes 3a and 3c.

Publication date: 1 October 2015
, Volume 210
Author(s): Jeanne-Marie Membré , Moctar Diao , Chantal Thorin , Grégoire Cordier , François Zuber , Stéphane André

Publication date: 1 October 2015
, Volume 210
Author(s): Dana Ziuzina , Lu Han , Patrick J. Cullen , Paula Bourke

Yersiniosis is strongly associated with the consumption of pork contaminated with enteropathogenic Yersinia enterocolitica, which is harbored by domestic pigs without showing clinical signs of disease. In contrast to data on Y. enterocolitica isolated from conventionally reared swine, investigations into the occurrence of Y. enterocolitica in wild boars in Germany are rare.

Food-borne pathogen persistence in soil fundamentally affects the production of safe vegetables and small fruits. Interventions that reduce pathogen survival in soil would have positive impacts on food safety by minimizing preharvest contamination entering the food chain. Laboratory-controlled studies determined the effects of soil pH, moisture content, and soil organic matter (SOM) on the survivability of this pathogen through the creation of single-parameter gradients.

Antimicrobial resistance in microbes poses a global and increasing threat to public health. The horizontal transfer of antimicrobial resistance genes was thought to be due largely to conjugative plasmids or transposons, with only a minor part being played by transduction through bacteriophages. However, whole-genome sequencing has recently shown that the latter mechanism could be highly important in the exchange of antimicrobial resistance genes between microorganisms and environments.

Bacteriophages UAB_Phi20, UAB_Phi78, and UAB_Phi87 were encapsulated in liposomes, and their efficacy in reducing Salmonella in poultry was then studied. The encapsulated phages had a mean diameter of 309 to 326 nm and a positive charge between +31.6 and +35.1 mV (pH 6.1). In simulated gastric fluid (pH 2.8), the titer of nonencapsulated phages decreased by 5.7 to 7.8 log units, whereas encapsulated phages were significantly more stable, with losses of 3.7 to 5.4 log units.

Infection by human pathogens through the consumption of fresh, minimally processed produce and solid plant-derived foods is a major concern of the U.S. and global food industries and of public health services. Enterohemorrhagic Escherichia coli O157:H7 is a frequent and potent foodborne pathogen that causes severe disease in humans. Biofilms formed by E. coli O157:H7 facilitate cross-contamination by sheltering pathogens and protecting them from cleaning and sanitation operations.

Campylobacter jejuni is a leading cause of human foodborne gastroenteritis worldwide. The interactions between this pathogen and the intestinal microbiome within a host are of interest as endogenous intestinal microbiota mediates a form of resistance to the pathogen. This resistance, termed colonization resistance, is the ability of commensal microbiota to prevent colonization by exogenous pathogens or opportunistic commensals. Although mice normally demonstrate colonization resistance to C.

Disposal of fecally contaminated poultry litter by land application can deliver pathogens and fecal indicator bacteria (FIB) into receiving waters via runoff. While water quality is regulated by FIB enumeration, FIB testing provides inadequate information about contamination source and health risk. This microbial source tracking (MST) study compared the persistence of the Brevibacterium sp.

Publication date: October 2015
, Volume 108
Author(s): M.K. Omer , B. Prieto , E. Rendueles , A. Alvarez-Ordoñez , K. Lunde , O. Alvseike , M. Prieto

This case report describes a recent botulism outbreak in commercial laying hens with a history of increased mortality and flaccid paralysis. Routine diagnostic gross examination and microscopy from seven hens were inconclusive, but botulinum neurotoxin (BoNT) in peripheral blood was neutralized with both type C and type D antitoxins in the mouse bioassay. During a farm visit, 10 additional hens from a 34-wk-old flock on the farm were selected for clinical examination and further sampling.

Livestock-associated meticillin-resistant Staphylococcus aureus belonging to clonal complex 398 (LA-MRSA CC398) is an important cause of zoonotic infections in many countries. Here, we describe the isolation of LA-MRSA CC398 from retail meat samples of United Kingdom (UK) farm origin. Our findings indicate that this lineage is probably established in UK pig farms and demonstrate a potential pathway for the transmission of LA-MRSA CC398 from livestock to humans in the UK.

Publication date: November 2015
Source:LWT - Food Science and Technology, Volume 64, Issue 1
Author(s): Lye Miyague , Renata E.F. Macedo , Giuseppe Meca , Richard A. Holley , Fernando B. Luciano

Rifampicin-resistant (RifR) strains have often been used in studies of Escherichia coli O157:H7 to assure more specific recovery. The present study compared the heat inactivation kinetics of rifampicin-resistant variants of pathogenic and nonpathogenic E. coli O157 strains with those of the wild-type parental strains. Spontaneous RifR derivatives of 11 pathogenic and six nonpathogenic E. coli O157 strains were selected.

Foodborne Pathogens and Disease , Vol. 0, No. 0.