Research Publications (Food Safety)

Abstract Staphylococcus aureus is a common pathogen capable of infecting both humans and animals and causing various severe diseases. Here, we aimed to determine the biological features and pathogenicity of S. aureus strain Sa9, of the incomplete hemolysis phenotype, isolated from bovine milk. Sa9 was classified as ST97 by multilocus sequence typing, and it showed increased β‐hemolysin expression and lower Hla and Hld expression levels compared with that in the S. aureus USA300 strain LAC.

T cell stimulation by bacterial superantigens induces a cytokine storm. After T cell activation and inflammatory cytokine secretion, regulatory T cells (Treg) are produced to suppress the immune response. Coccomyxa sp.KJ (IPOD FERM BP-22254), a green alga, is reported to regulate immune reactions. Therefore, we examined the effects of Coccomyxa sp.KJ extract (CE) on the superantigen-induced immune response.

Microbiology and Immunology, Accepted Article.

Microbiology and Immunology, EarlyView.

Microbiology and Immunology, Accepted Article. Clostridium botulinum causes infant and adult intestinal botulism by colonizing in the intestine and producing botulinum neurotoxin (BoNT). Antimicrobial agents are not currently used for treatment due to the potential facilitation of BoNT production and bacterial cell lysis, which releases toxins into the intestinal lumen.

Microbiology and Immunology, Accepted Article. Fibronectin (Fn) is an approximately 450 kDa glycoprotein that is comprised of 12 type I, 2 type II, and 15–17 type III modules. Fibrillation of Fn is important for tissue reconstitution and wound healing. We previously reported that Clostridium perfringens produces several Fn‐binding proteins (Fbps), two of which, FbpA and FbpB, bind to III1‐C (a fragment of Fn derived from the carboxyl‐terminal two‐thirds of the first type III module).

Microbiology and Immunology, Accepted Article.

Antimicrobial‐resistant bacteria and resistance determinants are of great concern to human and veterinary medicine worldwide. This article is protected by copyright. All rights reserved.

Brucellosis is a major zoonotic disease, and Brucella melitensis is the species most often associated with human infection. Vaccination is the most efficient tool for controlling animal brucellosis, with a consequent decrease of incidence of human infections. Commercially available live attenuated vaccines provide some degree of protection but retain residual pathogenicity to human and animals.

An important toxin‐antitoxin (TA) system hok/sok, encoded by R1 plasmid of Escherichia coli, is involved in post segregation killing of cells that have lost the plasmid. The lethal properties of hok protein have been utilized for the environmental containment of microbes and the development of potential vaccine candidates. We aim to demonstrate the potent anti‐microbial property of 19 amino acid (AA) long N‐terminal fragment of hok peptide.

Shiga‐toxigenic Escherichia coli (STEC) is a major bacterium responsible for disease resulting from foodborne infection, including bloody diarrhea and hemolytic uremic syndrome (HUS). STEC produces important virulence factors such as Shiga toxin (Stx) 1 and/or 2. In the STEC family, some Locus for Enterocyte Effacement (LEE)‐negative STEC produce two different types of cytotoxins, Stx2 and Subtilase cytotoxin (SubAB).

Salmonella enterica serovar Typhimurium (S. Typhimurium, STM) is a leading cause of non‐typhoidal salmonellosis (NTS) worldwide. The pathogenesis of NTS has been studied extensively using a streptomycin‐pretreated mouse colitis model with the limited numbers of laboratory S. Typhimurium strains. However, the pathogenicity of the clinically isolated S. Typhimurium (STMC) strains endemic in Thailand in mice has not been explored.

Antigen‐specific CD8+ T‐lymphocytes (cytotoxic T‐lymphocytes: CTL), as well as CD4+ T‐lymphocytes (helper T‐lymphocytes: Th), simultaneously play an important role in elimination of intracellular bacteria such as Mycobacterium tuberculosis and Listeria monocytogenes. Administration of T‐cell epitope short peptide needs large numbers of peptides for effective vaccination due to its easily degradable nature in vivo.

To clarify the persistence of extended‐spectrum β‐lactamase (ESBL) producers, 13 plasmids from two broiler farms were analyzed. On the farm not using antimicrobials, one plasmid from Klebsiella pneumoniae isolated from a day‐old chick was similar to that from Escherichia coli isolated a year later, with the deletion of two transposons. On the farm using antimicrobials, most circulating plasmids (8/9) in a flock of 40‐days‐old chicks were identical, although one from K.

The use of non‐human animal models for infection experiments is important for investigating the infectious processes of human pathogenic bacteria at the molecular level. Mammals, such as mice and rabbits, are also utilized as animal infection models, but large numbers of animals are needed for these experiments, which is costly, and fraught with ethical issues.

Vibrio vulnificus is a foodborne pathogen causing septicemia with high mortality rate. In this study, we explored how Escherichia coli, one of the commensal bacteria in human gastrointestinal tract, can interact with V. vulnificus. Our study showed that, the amount of biofilm produced by V. vulnificus was reduced in the presence of E. coli ATCC 35218, although the growth of V. vulnificus L‐180 remains unaffected. We also detected antibiofilm effect of E. coli culture supernatant against V.

Botulinum neurotoxin (BoNT) is the causative agent of botulism in humans and animals. Only BoNT serotype A subtype 1 (BoNT/A1) is clinically used because of its high potency and long duration of action. BoNT/A1 and BoNT/A subtype 2 (BoNT/A2) have high degree of amino acid sequence similarity in light chain (LC) (96%), whereas their N‐and C‐terminal heavy chain (HN and HC) differ by 13%.

TOLL‐interacting protein (Tollip) is a critical regulator of TLRs (toll‐like receptors) signaling pathway. It is predominantly associated with TLR2 and TLR4 during the acute inflammatory conditions and inhibits the TLR‐mediated NF‐κB activation by suppressing the auto‐phosphorylation of interleukin‐1 receptor associated kinase (IRAK1) and its kinase activity. This article describes about the Tollip in Labeo rohita (LrTollip), a highly valuable freshwater fish of the Indian subcontinent.

ABSTRACTS Non‐O1/non‐O139 nontoxigenic Vibrio cholerae associated with cholera‐like diarrhea has been reported in Kolkata, India. However, the property involved in the pathogenicity of these strains has remained unclear. We examined the character of 25 non‐O1/non‐O139 nontoxigenic V. cholerae isolated during 8 years from 2007 to 2014 in Kolkata.

In the 1980s, I found that the chromosomal β‐lactamase of Klebsiella pneumoniae LEN‐1 showed a very high similarity to the R‐plasmid‐mediated penicillinase TEM‐1 on amino acid sequence level, and this strongly suggested the TEM‐1 originated from the chromosomal penicillinases of K. pneumoniae or related bacteria.

Vibrio parahaemolyticus is a leading cause of seafood‐borne bacterial gastroenteritis in humans. Since its discovery in 1950, this bacterium has been isolated in widespread outbreaks and in sporadic cases of gastroenteritis worldwide. Although the exotoxin, thermostable direct hemolysin (TDH), had been the focus of extensive research on the pathogenicity of V. parahaemolyticus, the whole‐genome sequencing of a clinical isolate, RIMD2210633 strain, was a breakthrough in this field.

Multidrug efflux pumps play an important role in bacterial multidrug resistance by actively excreting antibiotics. The ABC‐type drug efflux pump MacAB was originally recorded as a macrolide‐specific pump. MacAB is also known to be required for the virulence of Salmonella enterica serovar Typhimurium following oral infection in mice.

Kenya is endemic for cholera with different waves of outbreaks having been documented since 1971. In recent years, new variants of Vibrio cholerae O1 have emerged and have replaced most of the traditional El Tor biotype globally. These strains also appear to have increased virulence, and it is important to describe and document their phenotypic and genotypic traits. This study characterized 146 V. cholerae O1 isolates from cholera outbreaks that occurred in Kenya between 1975 and 2017.