Research Publications (Food Safety)

Background

Over the last two decades, the prevalence of colistin resistance among the members of Enterobacteriaceae has been increasing, particularly among Klebsiella pneumoniae isolates; this limits the potential use of colistin and leads to worsened clinical outcomes.

Methods

We investigated the prevalence and genetic characteristics of colistin-resistant K. pneumoniae (COLR-KP) in clinical isolates using genomic sequencing.

Results

The acute radiation-induced intestinal injury (RIII) has raised much concerns and is influenced by non-cytocidal radiation effects including the perturbations in gut microbiota. Although a number of studies have reported alteration in gut microbiota following radiation, little is known about its dynamic variation in the progression of acute RIII.

Listeria monocytogenes (Lm) is a foodborne pathogen causing listeriosis. Invasive forms of the disease mainly manifest as septicaemia, meningitis and maternal-neonatal infections. Lm-associated respiratory infections are very rare and little known. We reported two Lm respiratory infection cases occurred in Central Italy during the summer of 2020, in the midst of the SARS-CoV2 pandemic.

Introduction

Panton Valentine leukocidin (PVL) is a virulence factor which is associated with methicillin sensitive and resistant Staphylococcus aureus (MSSA/MRSA) causing skin and soft tissue infections (SSTI). This study aimed to evaluate a novel lateral flow immunoassay (LFI) for PVL detection in S. aureus cultures and to describe their genotypic characterization.

Methods

Sepsis is a common and often treacherous medical emergency with a high mortality and long-term complications in survivors. Though antibiotic therapy can reduce death rate of sepsis significantly, it impairs gut microbiota (GM), which play imperative roles in human health.

Salmonella has been known as an important zoonotic pathogen that can cause a variety of diseases in both animals and humans. Poultry are the main reservoir for the Salmonella serovars Salmonella Pullorum (S. Pullorum), Salmonella Gallinarum (S. Gallinarum), Salmonella Enteritidis (S. Enteritidis), and Salmonella Typhimurium (S. Typhimurium).

Klebsiella pneumoniae carbapenemase genes (blaKPC) play an important role in carbapenem-resistant Enterobacteriaceae in China. A rapid detection method for blaKPC genes and investigations into the molecular characteristics of blaKPC positive Klebsiella pneumoniae were necessary. In this study, an easy and rapid recombinase aided amplification assay (RAA) for blaKPC was established. This protocol could be completed at 39°C in 15–20 min.

Background

There is a paucity of studies using clinical characteristics and whole-genome sequencing together to fully identify the risk factors of patients with Klebsiella pneumoniae (KP) bloodstream infection (BSI).

Methods

Gastrointestinal (GI) infections in sheep have significant implications for animal health, welfare and productivity, as well as being a source of zoonotic pathogens. Interactions between pathogens and epithelial cells at the mucosal surface play a key role in determining the outcome of GI infections; however, the inaccessibility of the GI tract in vivo significantly limits the ability to study such interactions in detail.

Campylobacter jejuni infection is a leading cause of foodborne disease, common to children, adult travelers, and military populations in low- to middle-income countries. In the absence of a licensed vaccine, efforts to evaluate prophylactic agents are underway.

Listeria monocytogenes (LM) has been proposed as vaccine vector in various cancers and infectious diseases since LM induces a strong immune response. In this study, we developed a novel and safe LM-based vaccine vector platform, by engineering a triple attenuated mutant (Lm3Dx) (ΔactA, ΔinlA, ΔinlB) of the wild-type LM strain JF5203 (CC 1, phylogenetic lineage I).

Untreated wastewater is a reservoir for multidrug-resistant bacteria, but its role in the spread of antibiotic resistance in the human population remains poorly investigated. In this study, we isolated a KPC-2-producing ST2787 Klebsiella quasipneumoniae subsp. quasipneumoniae (WW14A), recovered from raw sewage at a wastewater treatment plant in Argentina in 2018 and determined its complete genome sequence. Strain WW14A was resistant to all β-lactams, ciprofloxacin and amikacin.

Objective

This study aims to analyze the molecular epidemiology, resistance, and pathogenicity of Salmonella enterica subsp. diarizonae isolated from children.

Methods

Whole genome sequencing was carried out, and molecular serotypes, sequence types, resistance genes, and virulence genes of S. enterica subsp. diarizonae isolates were analyzed. Antimicrobial susceptibility test was determined by commercialized microdilution method.

Results

The study investigated the occurrence of antimicrobial resistance genes and virulence determinants in Vibrio species recovered from different freshwater sheds in rustic milieu. A total of 118 Vibrio isolates comprising Vibrio fluvialis (n=41), Vibrio mimicus (n=40) and V. vulnificus (n=37) was identified by amplification of ToxR, vmh and hsp60 genes. The amplification of virulence genes indicated that V.

Enterotoxigenic Escherichia coli (ETEC) is a WHO priority pathogen and vaccine target which causes infections in low-income and middle-income countries, travelers visiting endemic regions. The global urgent demand for an effective preventive intervention has become more pressing as ETEC strains have become increasingly multiple antibiotic resistant. However, the vaccine development pipeline has been slow to address this urgent need.

Objective

Frailty is a common geriatric syndrome that is diagnosed and staged based mainly on symptoms. We aimed to evaluate frailty-related alterations of the intestinal permeability and profile fecal microbiota of healthy and frail older adults to identify microbial biomarkers of this syndrome.

Methods

Efflux pumps are one of the predominant microbial resistant mechanisms leading to the development of multidrug resistance. In Staphylococcus aureus, overexpression of NorA protein enables the efflux of antibiotics belonging to the class of fluoroquinolones and, thus, makes S. aureus resistant. Hence, NorA efflux pumps are being extensively exploited as the potential drug target to evade bacterial resistance and resensitize bacteria to the existing antibiotics.

Urinary tract infection (UTI) is one of the most common bacterial infections and UTI is the most common extraintestinal infectious disease entity in women worldwide. Uropathogenic Escherichia coli (UPEC) is the leading cause of UTI. While antimicrobial resistance has emerged as one of the principal problems of UTI, little is known about the epidemiology of UPEC isolated from female patients in Shanghai.

Autoinducer-2 (AI-2) is believed to be a bacterial interspecies signaling molecule that plays an important role in the regulation of the physiological behaviors of bacteria. The effect of AI-2 on the process of necrotizing enterocolitis (NEC) is unknown, and the aim of this study was to study the effect of AI-2 in a mouse NEC model. C57BL/6 mouse pups were randomly divided into three groups: the control group, the NEC group, and the NEC+AI-2 (NA) group.

Bloodstream infections (BSIs), the presence of microorganisms in blood, are potentially serious conditions that can quickly develop into sepsis and life-threatening situations. When assessing proper treatment, rapid diagnosis is the key; besides clinical judgement performed by attending physicians, supporting microbiological tests typically are performed, often requiring microbial isolation and culturing steps, which increases the time required for confirming positive cases of BSI.

Introduction

L-arabinose inducible promoters are commonly used in gene expression analysis. However, nutrient source and availability also play a role in biofilm formation; therefore, L-arabinose metabolism could impact biofilm development. In this study we examined the impact of L-arabinose on Salmonella enterica serovar Typhimurium (S. Typhimurium) biofilm formation. Using mutants impaired for the transport and metabolism of L-arabinose, we showed that L-arabinose metabolism negatively impacts S.

The emergence and prevalence of carbapenem-resistant Enterobacteriaceae (CRE) have drawn worldwide attention. Ceftazidime/avibactam (CAZ/AVI) gives us a valuable alternative strategy to treat CRE infections. Unfortunately, CAZ/AVI resistance could occur during CAZ/AVI treatment.

In this study, multidrug-resistant (MDR) Escherichia coli isolates from retail food and humans assigned into similar Multilocus Sequence Types (MLST) were analyzed using whole genome sequencing (WGS). In silico analysis of assembled sequences revealed the existence of multiple resistance genes among the examined E. coli isolates. Of the six CTX-M-producing isolates from retail food, blaCTX-M-14 was the prevalent variant identified (83.3%, 5/6).