Assessment of Multifunctional Activity of a Postbiotic Preparation Derived from Postbiotic-P6.

Postbiotics possess various functional activities, closely linked to their source bacterial strains and preparation methods. Therefore, the functional activities of postbiotics need to be evaluated through in vitro and in vivo methods. This study aims to prepare a postbiotic and explore its antihemolytic, anti-inflammatory, antioxidant, and antibacterial activities.

Comparative Analysis of Growth, Survival, and Virulence Characteristics of Isolated from Imported Meat.

is an important foodborne pathogen with worldwide prevalence. Understanding the variability in the potential pathogenicity among strains of different subtypes is crucial for risk assessment. In this study, the growth, survival, and virulence characteristics of 16 strains isolated from imported meat in China (2018-2020) were investigated.

Development of Recombinase Aided Amplification (RAA)-Exo-Probe Assay for the Rapid Detection of Shiga Toxin-Producing Escherichia coli.

Background: Shiga toxin-producing Escherichia coli (STEC) is a significant cause of foodborne illness causing various gastrointestinal diseases including hemolytic uremic syndrome (HUS), the most severe form, which can lead to kidney failure or even death.

Objective: Here, we report the development of recombinase aided amplification (RAA)-exo-probe assays targeting the stx1 and stx2 genes for the rapid detection of STEC in food samples.

Methods: Primers and exo-probes were designed and optimized for the detection of stx1 and stx2 using RAA technology.

Sensitive and Rapid Detection of Escherichia coli O157:H7 From Beef Samples Based on Recombinase Aided Amplification Assisted CRISPR/Cas12a System.

Background: Escherichia coli O157:H7, being the cause of hemorrhagic colitis in humans, is recognized as one of the most dangerous and widespread foodborne pathogens. A highly specific, sensitive, and rapid E. coli O157:H7 detection method needs to be developed since the traditional detection methods are complex, costly, and time-consuming.

Development of Recombinase-Aided Amplification (RAA)-Exo-Probe and RAA-CRISPR/Cas12a Assays for Rapid Detection of in Food Samples.

is the major cause of campylobacteriosis, one of the most common foodborne illnesses worldwide. Here, we report the development of RAA-exo-probe and RAA-CRIPSR/Cas12a assays for the detection of in food samples. The two assays were found to be highly specific to and highly sensitive, as they were one log more sensitive compared to the traditional culture method, with detection thresholds of 9 and 5 copies per reaction, respectively.

Validation of the Tadpole Real-Time PCR Identification Kit.

The gene-based real-time PCR method for identification of is more simple, rapid and accurate than the traditional biochemical method. A performance validation of the Tadpole Real-Time PCR Identification Kit was performed. The assay uses TaqMan Real-time PCR technology to amplify target genes from isolated colonies.

The Role of AcrAB-TolC Efflux Pump in Mediating Fluoroquinolone Resistance in Naturally Occurring Salmonella Isolates from China.

The involvement of AcrAB-TolC efflux pump in regulating fluoroquinolone resistance of naturally occurring Salmonella isolates is insufficiently investigated. In this study, the regulatory genes, acrR, ramR, marRAB, and soxRS of AcrAB-TolC efflux pump, of 27 naturally occurring fluoroquinolone-resistant Salmonella isolates collected in China were sequenced. The expression levels of acrB, ramA, marA, and soxS were also examined using quantitative real-time polymerase chain reaction.

Virulence characterization of non-O157 Shiga toxin-producing Escherichia coli isolates from food, humans and animals.

A total of 359 non-O157 STEC isolates from food, humans and animals were examined for serotypes, Shiga toxin subtypes and intimin subtypes. Isolates solely harboring stx2 from the three sources were selected for Vero cell cytotoxicity test. stx subtypes in eae negative isolates were more diverse than in eae positive isolates primarily carrying stx2a.

Pathogenicity islands in Shiga toxin-producing Escherichia coli O26, O103, and O111 isolates from humans and animals.

Non-O157 Shiga toxin-producing Escherichia coli (STEC) are increasingly recognized as foodborne pathogens worldwide. Serogroups O26, O111, and O103 cause most known outbreaks related to non-O157 STEC. Pathogenicity islands (PAIs) play a major role in the evolution of STEC pathogenicity.

Rapid identification and differentiation of non-O157 Shiga toxin-producing Escherichia coli using polymerase chain reaction coupled to electrospray ionization mass spectrometry.

A polymerase chain reaction (PCR)-mass spectroscopy assay was developed to identify non-O157 Shiga toxin-producing Escherichia coli (STEC) with Plex-ID biosensor system, a platform identifying short PCR amplicons by specific base compositions. This assay simultaneously amplifies five fragments of two housekeeping genes, two subunits of stx2 gene, and four other virulence genes of STEC. A total of 164 well-characterized STEC isolates were examined with the assay to build a DNA base composition database.

Molecular subtyping and virulence gene analysis of Listeria monocytogenes isolates from food.

A total of 67 Listeria monocytogenes isolates from 698 raw meat samples were characterized for molecular serogroup identification and antimicrobial susceptibility. Approximately one third (32.8%) of the isolates belonged to molecular serogroup 1/2a, 3a, followed by 1/2c, 3c (26.

Distribution of pathogenicity islands OI-122, OI-43/48, and OI-57 and a high-pathogenicity island in Shiga toxin-producing Escherichia coli.

Pathogenicity islands (PAIs) play an important role in Shiga toxin-producing Escherichia coli (STEC) pathogenicity. The distribution of PAIs OI-122, OI-43/48, and OI-57 and a high-pathogenicity island (HPI) were determined among 98 STEC strains assigned to seropathotypes (SPTs) A to E. PCR and PCR-restriction fragment length polymorphism assays were used to identify 14 virulence genes that belonged to the four PAIs and to subtype eae and stx genes, respectively.

Non-O157 Shiga toxin-producing Escherichia coli in retail ground beef and pork in the Washington D.C. area.

The prevalence and characteristics of non-O157 Shiga toxin-producing Escherichia coli (STEC) in retail ground meat from the Washington D.C. area were investigated in this study.

[Antimicrobial susceptibility and related genes of Salmonella serovars from retail food in Shaanxi province].

Objective: Salmonella isolates from retail food were examined for antimicrobial susceptibility and further characterized to better understand the development and dissemination of antimicrobial resistance among foodborne Salmonella in China.

Methods: Antimicrobial susceptibility of 359 Salmonella isolates was determined by using agar dilution methods recommended by the Clinical and Laboratory Standards Institute. Antimicrobial resistance integrons and resistance genes were identified using PCR.

Prevalence and characterization of Salmonella serovars in retail meats of marketplace in Shaanxi, China.

A total of 764 retail meat including 515 chicken, 91 pork, 78 beef and 80 lamb samples were collected in Shaanxi Province of China in 2007-2008 to determine the prevalence of Salmonella. The isolates were characterized using serotyping, antimicrobial susceptibility testing, and the presence of bla(CMY-2) and bla(TEM) and class I integrons. Selective serovars were further subtyped using PFGE.

[Detection and analysis of antibiotic resistance of Salmonella from retail meats in some districts of Shaanxi province].

Objective: Salmonella isolates recovered from retail meats that were collected in supermarkets and free markets in Xi'an and Yangling areas of Shaanxi province were studied to determine antibiotic susceptibility.

Method: Antimicrobial susceptibility to 14 antibiotics of 193 salmonella isolates were determined by using agar dilution method, which was recommended by National Committee of Clinical Laboratory Standard (NCCLS), and E.coli ATCC25922 and E.