Research Publications (Food Safety)

by Junho Cho, William F. C. Rigby, Ambrose L. Cheung Patients with cystic fibrosis (CF) often suffer recurrent bronchial bacterial infections that lead to deterioration of lung function over time. The infections in CF patients are often due to S. aureus and P. aeruginosa that colonize the airways. Significantly, methicillin-resistant S.

An estimated 1000,000 domestic salmonellosis cases are attributed to food as a vehicle of exposure. Among Food Safety and Inspection Service (FSIS)-regulated products, approximately 360,000 salmonellosis cases are associated with consumption of meat, poultry, and egg products. Salmonella vaccination programs instituted in U.S.

S. aureus infection of bone is difficult to eradicate due to its ability to colonize the osteocyte-lacuno-canalicular network (OLCN), rendering it resistant to standard-of-care (SOC) antibiotics. To overcome this, we proposed two bone-targeted bisphosphonate-conjugated antibiotics (BCA): bisphosphonate-conjugated sitafloxacin (BCS) and hydroxybisphosphonate-conjugate sitafloxacin (HBCS). Initial studies demonstrated that the BCA kills S. aureus in vitro.

Probiotics are special bacterial strains with strain specific impacts. They can affect health condition in intestine by producing organic acid, competing with pathogens and maintaining cells homeostasis.

Exopolysaccharides (EPS) produced by lactic acid bacteria are complicated polymers with industrial applications. LAB were isolated, screened for EPS production, and their probiotic properties determined. The anti-biofilm activity of EPS was investigated. Safety of EPS-producing isolate was investigated and it was molecularly identified through 16S rRNA sequencing.

Pigs have been shown to be a reservoir for recently emerging livestock-associated Staphylococcus aureus (LA-SA), including methicillin resistant strains in many countries worldwide. However, there is sparse information about LA-SA strains circulating in Zambia. This study investigated the prevalence, phenotypic and genotypic characteristics of S. aureus from pigs and workers at farms and abattoirs handling pigs in Lusaka Province of Zambia.

The fulminating zoonotic pathogen Vibrio vulnificus is the causative agent of fatal septicemia in humans and fish, raising tremendous economic burdens in healthcare and the aquaculture industry. V. vulnificus exploits various virulence factors, including biofilm-related factors and exotoxins, for its persistence in nature and pathogenesis during infection.

Journal of Clinical Microbiology, Ahead of Print. Fosfomycin is a phosphonic acid derivative active against a wide spectrum of Gram-positive and Gram-negative pathogens. It is used for the treatment of uncomplicated urinary tract infections (uUTI) or severe infections by oral or intravenous (i.v.) administration.

Journal of Bacteriology, Ahead of Print. Staphylococcus aureus is a medically important pathogen with high metabolic versatility allowing it to infect various niches within a host. S. aureus utilizes two major transcriptional regulators, namely, CodY and CcpA, to remodel metabolic and virulence gene expression in response to changing environmental conditions.

Antimicrobial Agents and Chemotherapy, Ahead of Print. Staphylococcus aureus is a common cause of severe infections, and its widespread antibiotic resistance necessitates search for alternative therapies, such as inhibition of virulence. As S. aureus produces multiple individual virulence factors, inhibition of an entire regulatory system might provide better effects than targeting each virulence factor separately. Herein, we describe two novel inhibitors of S.

Letters in Applied Microbiology, Accepted Article. Numerous studies have attempted to restore the function of the tumour suppressor p53 as an anticancer strategy through gene delivery. However, most studies employed non-bacterial vectors to deliver p53.

Journal of Fish Diseases, EarlyView. Bacterial mutation and genetic diversity in aquaculture have led to increasing phenotypic variances, which can weaken or invalidate strategies for controlling diseases. However, few studies have monitored the degree of mutation in fish bacterial pathogens caused by environmental pressure within a short period.

This study sought to І)investigate the effect of varying concentrations of salt on the survival of Gram-negative bacteria in artificial seawater (ASW; pH 6) stored at 4 °C, ІІ)examine the culturable populations of Vibrio vulnificus persisting in ASW with or without 1000 U/mg catalase or 0.1% sodium pyruvate (pH 6) under aerobic and oxygen-restricted environments at 4 °C, and ІІІ)determine whether double layer agar plate (DLAP) methods can improve the culturability of 

Poultry is one of the fastest growing industries due to advantages in land use, rapid production and advances in feed technology. The rising trend in the consumption of poultry meat over the last 50 years has also increased concerns about food safety. Campylobacter jejuni is the leading bacterial cause of gastroenteritis, the foremost cause of foodborne deaths.

In the present study, primer-probe sets for the detection of Salmonella enterica and S. enterica serovar Montevideo were developed based on comparative genomics. Genomic information of 706 strains of S. enterica, including 23 strains of serovar Montevideo, was retrieved from National Center for Biotechnology Information (NCBI) RefSeq and analyzed by the panX program.

Foodborne outbreaks are closely associated with the formation of biofilms. However, due to their complexity of the formation and structure, studies of dual-species biofilms are still required. The aim of this study was to analyse the dual-species biofilm of Bacillus cereus and Pseudomonas fluorescens by investigating the interactions between the two species.

Antimicrobial resistance in Listeria monocytogenes biofilms is considered a risk. When using disinfectants, the minimum inhibitory concentration (MIC) must be contemplated to avoid resistance. The objective of the present study was to determine the MIC of four essential oils in four L. monocytogenes strains. Once the MICs were obtained, the effect of subinhibitory doses of the most effective oil was determined.

Some serovars of Salmonella are not or rare found to cause salmonellosis in human. In our clinic-based surveillance, three rare Salmonella 4,5,12:a:- strains were recovered from three patients with diarrhea. To explore their genetic and epidemiological characteristics and pathogenesis, we conducted whole-genome sequencing, in vitro invasion assays in mammalian cells, and in vivo virulence assays in an animal model.

In 2019, the United States National Antimicrobial Resistance Monitoring System (NARMS) surveyed raw salmon, shrimp, and tilapia from retail grocery outlets in eight states to assess the prevalence of bacterial contamination and antimicrobial resistance (AMR) in the isolates.

Bacterial pathogens, such as Shiga toxin-producing Escherichia coli (STEC) and Shigella spp., are important causes of foodborne illness internationally. Recovery of these organisms from foods is critical for food safety investigations to support attribution of illnesses to specific food commodities; however, isolation of bacterial cultures can be challenging. Methods for the isolation of STEC and Shigella spp.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is an important zoonotic microorganism that is increasingly causing public health concern worldwide. The objective of this study was to determine the transmission and occurrence of MRSA in a slaughterhouse environment and evaluate its antimicrobial resistance and genetic characterization. In this study, we conducted a comprehensive epidemiological survey of S.

Methicillin-resistant Staphylococcus epidermidis (MRSE) strains are increasingly emerging as serious pathogens because they can be resistant to many antibiotics called multidrug resistance (MDR) that limit the therapeutic options. In the case of vancomycin- and rifampin-resistant MDR-MRSE, the physicians are not allowed to increase the doses of antibiotics because of severe toxicity.

Applied and Environmental Microbiology, Ahead of Print. Bacillus cereus sensu lato (s.l.) includes foodborne pathogens, as well as beneficial microorganisms, such as bioinsecticides. Some of the beneficial and commercially used B. cereus s.l. strains have been shown to carry enterotoxin genes, the products of which can cause toxicoinfection in humans.