Small molecules targeting LapB protein prevent Listeria attachment to catfish muscle

Exploration of risk analysis and elimination methods for a Cr(VI)-removal recombinant strain through a biosafety assessment in mice

Though recombinant strains are increasingly recognized for their potential in heavy metal remediation, few studies have evaluated their safety. Moreover, biosafety assessments of fecal-oral pathway exposure at country as well as global level have seldom analyzed the health risks of exposure to microorganisms from a microscopic perspective. The present study aimed to predict the long-term toxic effects of recombinant strains by conducting a subacute toxicity test on the chromium-removal recombinant strain 3458 and analyzing the gut microbiome. The available disinfection methods were also evaluated. The results showed that strain 3458 induced liver damage and affected renal function and lipid metabolism at 1.0 × 1011 CFU/mL, which may be induced by its carrier strain, pET-28a. Strain 3458 poses the risk of increasing the number of pathogenic bacteria under prolonged exposure. When 500 mg L-1 chlorine-containing disinfectant or 250 mg L-1 chlorine dioxide disinfectant was added for 30 min, the sterilization rate exceeded 99.9 %. These findings suggest that existing wastewater disinfection methods can effectively sterilize strain 3458, ensuring its application value. The present study can serve a reference for the biosafety evaluation of the recombinant strain through exposure to the digestive tract and its feasibility for application in environmental pollution remediation.

Antimicrobial Resistance and Recent Alternatives to Antibiotics for the Control of Bacterial Pathogens with an Emphasis on Foodborne Pathogens

Antimicrobial resistance (AMR) is one of the most important global public health problems. The imprudent use of antibiotics in humans and animals has resulted in the emergence of antibiotic-resistant bacteria. The dissemination of these strains and their resistant determinants could endanger antibiotic efficacy. Therefore, there is an urgent need to identify and develop novel strategies to combat antibiotic resistance. This review provides insights into the evolution and the mechanisms of AMR. Additionally, it discusses alternative approaches that might be used to control AMR, including probiotics, prebiotics, antimicrobial peptides, small molecules, organic acids, essential oils, bacteriophage, fecal transplants, and nanoparticles.

Whole-Genome Sequencing Characterization of Virulence Profiles of Listeria monocytogenes Food and Human Isolates and In Vitro Adhesion/Invasion Assessment

Listeria monocytogenes (Lm) is the causative agent of human listeriosis. Lm strains have different virulence potential. For this reason, we preliminarily characterised via Whole-Genome Sequencing (WGS) some Lm strains for their key genomic features and virulence-associated determinants, assigning the clonal complex (CC). Moreover, the ability of the same strains to adhere to and invade human colon carcinoma cell line Caco-2, evaluating the possible correspondence with their genetic virulence profile, was also assessed. The clinical strains typed belonged to clonal complex (CC)1, CC31, and CC101 and showed a very low invasiveness. The Lm strains isolated from food were assigned to CC1, CC7, CC9, and CC121. All CC1 carried the hypervirulence pathogenicity island LIPI-3 in addition to LIPI-1. Premature stop codons in the inlA gene were found only in Lm of food origin belonging to CC9 and CC121. The presence of LIPI2_inlII was observed in all the CCs except CC1. The CC7 strain, belonging to an epidemic cluster, also carried the internalin genes inlG and inlL and showed the highest level of invasion. In contrast, the human CC31 strain lacked the lapB and vip genes and presented the lowest level of invasiveness. In Lm, the genetic determinants of hypo- or hypervirulence are not necessarily predictive of a cell adhesion and/or invasion ability in vitro. Moreover, since listeriosis results from the interplay between host and virulence features of the pathogen, even hypovirulent clones are able to cause infection in immunocompromised people.