-
Microbiology Resource Announcements Jun 2024, a concerning foodborne pathogen, causes severe infections in vulnerable subjects such as pregnant women and the elderly. In this article, we present the complete...
, a concerning foodborne pathogen, causes severe infections in vulnerable subjects such as pregnant women and the elderly. In this article, we present the complete genome sequence of P4_LIS, an isolated from a patient with invasive bacteria infection.
PubMed: 38864617
DOI: 10.1128/mra.01240-23 -
Frontiers in Veterinary Science 2024Examining the microbiological characteristics of pet food is imperative to safeguard the health and well-being of companion animals, pet owners, and the surrounding...
Examining the microbiological characteristics of pet food is imperative to safeguard the health and well-being of companion animals, pet owners, and the surrounding environment. Domestic animals, known for carrying harmful microorganisms, pose a significant health risk, especially in close proximity to people and children. Notably, no studies have previously investigated pet food quality in the Gulf Cooperation Council countries, in particular, the United Arab Emirates (UAE). This study examined the microbiological quality of all stock keeping units (SKUs) of pet foods marketed in UAE ( = 118). Parameters assessed include Total Aerobic Microbial Count (TAMC), , Total Yeast and Mold Count (TYMC), , , and species. Among the 118 samples, 33 (28%) exceeded the acceptable TAMC limit of 10 CFU/g, highlighting significant variations based on manufacturers and ingredients. Eight samples (7%) surpassed the maximum limit of 3 × 10 CFU/g. TYMC levels exhibited variation, with 33 (28%) exceeding the limit of 10 CFU/g. was identified in 44 (37%) of the samples, while was not detected. contamination was observed in 28 (24%) of the samples. Statistical analyses revealed associations between pet food characteristics and microbial quality, underscoring the imperative for international standards to ensure the safety of pet food. These findings carry significant implications for pet owners, regulatory bodies, and the pet food industry, emphasizing the need for ongoing efforts to enhance the overall quality and safety of pet food products.
PubMed: 38855408
DOI: 10.3389/fvets.2024.1389981 -
BioRxiv : the Preprint Server For... May 2024Attenuated strains of the intracellular pathogen can deliver genetically encoded payloads inside tumor cells. preferentially accumulates and propagates inside...
Attenuated strains of the intracellular pathogen can deliver genetically encoded payloads inside tumor cells. preferentially accumulates and propagates inside immune-suppressed tumor microenvironments. To maximize the payload impact in tumors and minimize damage to healthy tissues, it is desirable to induce payload synthesis when bacteria are eliminated from the healthy tissues but are grown to high numbers intratumorally. Here, we have engineered a tightly controlled gene expression system for intracellular inducible with a cumin derivative, cumate. Upon cumate addition, expression of a reporter gene is increased in growing by 80-fold, and in intracellular in murine tumors by 10-fold. This study demonstrates the feasibility of activating gene expression in intracellular bacteria in live animals using an edible inducer. The system is expected to enhance the efficacy and safety of the attenuated strains as antitumor payload delivery bacterial drones.
PubMed: 38853860
DOI: 10.1101/2024.05.28.596178 -
Spectrochimica Acta. Part A, Molecular... May 2024Among the severe foodborne illnesses, listeriosis resulting from the pathogen Listeria monocytogenes exhibits one of the highest fatality rates. This study investigated...
Among the severe foodborne illnesses, listeriosis resulting from the pathogen Listeria monocytogenes exhibits one of the highest fatality rates. This study investigated the application of near infrared hyperspectral imaging (NIR-HSI) for the classification of three L. monocytogenes serotypes namely serotype 4b, 1/2a and 1/2c. The bacteria were cultured on Brain Heart Infusion agar, and NIR hyperspectral images were captured in the spectral range 900-2500 nm. Different pre-processing methods were applied to the raw spectra and principal component analysis was used for data exploration. Classification was achieved with partial least squares discriminant analysis (PLS-DA). The PLS-DA results revealed classification accuracies exceeding 80 % for all the bacterial serotypes for both training and test set data. Based on validation data, sensitivity values for L. monocytogenes serotype 4b, 1/2a and 1/2c were 0.69, 0.80 and 0.98, respectively when using full wavelength data. The reduced wavelength model had sensitivity values of 0.65, 0.85 and 0.98 for serotype 4b, 1/2a and 1/2c, respectively. The most relevant bands for serotype discrimination were identified to be around 1490 nm and 1580-1690 nm based on both principal component loadings and variable importance in projection scores. The outcomes of this study demonstrate the feasibility of utilizing NIR-HSI for detecting and classifying L. monocytogenes serotypes on growth media.
PubMed: 38850824
DOI: 10.1016/j.saa.2024.124579 -
Italian Journal of Food Safety May 2024The original notifications (n=1355) managed by the Rapid Alert System for Food and Feed of the Tuscany region in the seven-year period 2015-2021 were analyzed. 68.9% of...
The original notifications (n=1355) managed by the Rapid Alert System for Food and Feed of the Tuscany region in the seven-year period 2015-2021 were analyzed. 68.9% of them were classified as alert notifications, and they mostly originated (56.3%) from official controls on the market, followed by the company's own checks (29.1%). Italy was the most represented notifying country (73.3%) and the most represented country of origin of the notified products (64.5%). Out of the 28 considered food categories, "fish and products thereof" (F), "cereals and bakery products" (C), "bivalve mollusks and products thereof" (B), and "meat and meat products (other than poultry)" (M) were the most notified. F were especially notified for the presence of heavy metals (45.7%), C for undeclared allergens (32.1%), B for microbial contaminants (, 49.6%), and M for pathogenic microorganisms (55.9%), mostly spp. and This study provides an updated framework for the main food safety issues at the regional level. The Rapid Alert System for Food and Feed should be periodically analyzed to evaluate historical trends and emerging or poorly known hazards. This is especially important for the planning of official control activities and the prevention of risks through the food supply chain.
PubMed: 38846050
DOI: 10.4081/ijfs.2024.12341 -
Microbiology Spectrum Jun 2024The study aimed to investigate the antibacterial activity, cytotoxicity, and mechanism of action of the non-ionic, cyclic lipopeptide, serrawettin W2-FL10 against ....
UNLABELLED
The study aimed to investigate the antibacterial activity, cytotoxicity, and mechanism of action of the non-ionic, cyclic lipopeptide, serrawettin W2-FL10 against . W2-FL10 exhibited potent activity against the Gram-positive bacteria , , , and , with minimum inhibitory concentration (MIC) values ranging from 6.3 to 31.3 μg/mL, while no activity was observed against Gram-negative bacteria. Broth microdilution assays showed that W2-FL10 interacted with key cell membrane components, such as lipid phosphatidyl glycerol and lipoteichoic acid of . Upon membrane interaction, W2-FL10 dissipated membrane potential within 12 min and increased membrane permeability within 28-40 min, albeit at slower rates and higher concentrations than the lytic peptide melittin. The observed membrane permeability, as detected with propidium iodide (PI), may be attributed to transmembrane pores/lesions, possibly dependent on dimer-driven lipopeptide oligomerization in the membrane. Scanning electron microscopy (SEM) imaging also visually confirmed the formation of lesions in the cell wall of one of the strains, and cell damage within 1 h of exposure to W2-FL10, corroborating the rapid time-kill kinetics of the strains. This bactericidal action against the strains corresponded to membrane permeabilization by W2-FL10, indicating that self-promoted uptake into the cytosol may be part of the mode of action. Finally, this lipopeptide exhibited low to moderate cytotoxicity to the Chinese hamster ovarian (CHO) cell line in comparison to the control (emetine) with an optimal lipophilicity range (log D value of 2.5), signifying its potential as an antibiotic candidate.
IMPORTANCE
Antimicrobial resistance is a major public health concern, urgently requiring antibacterial compounds exhibiting low adverse health effects. In this study, a novel antibacterial lipopeptide analog is described, serrawettin W2-FL10 (derived from ), with potent activity displayed against . Mechanistic studies revealed that W2-FL10 targets the cell membrane of , causing depolarization and permeabilization because of transmembrane lesions/pores, resulting in the leakage of intracellular components, possible cytosolic uptake of W2-FL10, and ultimately cell death. This study provides the first insight into the mode of action of a non-ionic lipopeptide. The low to moderate cytotoxicity of W2-FL10 also highlights its application as a promising therapeutic agent for the treatment of bacterial infections.
PubMed: 38842361
DOI: 10.1128/spectrum.02952-23 -
Food Microbiology Sep 2024Challenge tests are commonly employed to evaluate the growth behavior of L. monocytogenes in food matrices; they are known for being expensive and time-consuming. An...
Challenge tests are commonly employed to evaluate the growth behavior of L. monocytogenes in food matrices; they are known for being expensive and time-consuming. An alternative could be the use of predictive models to forecast microbial behavior under different conditions. In this study, the growth behavior of L. monocytogenes in different fresh produce was evaluated using a predictive model based on the Gamma concept considering pH, water activity (a), and temperature as input factors. An extensive literature search resulted in a total of 105 research articles selected to collect growth/no growth behavior data of L. monocytogenes. Up to 808 L. monocytogenes behavior values and physicochemical characteristics were extracted for different fruits and vegetables. The predictive performance of the model as a tool for identifying the produce commodities supporting the growth of L. monocytogenes was proved by comparing with the experimental data collected from the literature. The model provided satisfactory predictions on the behavior of L. monocytogenes in vegetables (>80% agreement with experimental observations). For leafy greens, a 90% agreement was achieved. In contrast, the performance of the Gamma model was less satisfactory for fruits, as it tends to overestimate the potential of acid commodities to inhibit the growth of L. monocytogenes.
Topics: Listeria monocytogenes; Vegetables; Fruit; Food Microbiology; Hydrogen-Ion Concentration; Temperature; Models, Biological; Water; Colony Count, Microbial; Food Contamination
PubMed: 38839220
DOI: 10.1016/j.fm.2024.104554 -
Fitoterapia Jun 2024This study determined chemical profiles, antibacterial and antibiofilm activities of the essential oils (EOs) obtained by A. visnaga aerial parts and F. vulgare fruits....
Antibacterial, antibiofilm, and chemical profiles of Ammi visnaga L. and Foeniculum vulgare mill. Essential oils, and ADMET, molecular docking investigation of essential oils major components.
This study determined chemical profiles, antibacterial and antibiofilm activities of the essential oils (EOs) obtained by A. visnaga aerial parts and F. vulgare fruits. Butanoic acid, 2-methyl-, 3-methylbutyl ester (38.8%), linalyl propionate (34.7%) and limonene (8.5%) resulted as main constituents of A. visnaga EO. In F. vulgare EO trans-anethole (76.9%) and fenchone (14.1%) resulted as main components. The two EOs were active against five bacterial strains (Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus) at different degrees. The MIC values ranged from 5 ± 2 to 10 ± 2 μL/mL except for S. aureus (MIC >20 μL/mL). EOs exhibited inhibitory effect on the formation of biofilm up to 53.56 and 48.04% against E. coli and A. baumannii, respectively and activity against bacterial metabolism against A. baumannii and E. coli, with biofilm-inhibition ranging from 61.73 to 73.55%. The binding affinity of the identified components was estimated by docking them into the binding site of S. aureus gyrase (PDB code 2XCT) and S. aureus tyrosyl-tRNA synthetase (PDB code 1JIJ). trans-Anethole and butanoic acid, 2-methyl-, 3-methylbutyl ester showed relatively moderate binding interactions with the amino acid residues of S. aureus tyrosyl-tRNA synthetase. In addition, almost all predicted compounds possess good pharmacokinetic properties with no toxicity, being inactive for cytotoxicity, carcinogenicity, hepatotoxicity, mutagenicity and immunotoxicity parameters. The results encourage the use of these EOs as natural antibacterial agents in food and pharmaceutical industries.
PubMed: 38838824
DOI: 10.1016/j.fitote.2024.106047 -
Open Forum Infectious Diseases Jun 2024Among 15 strains of tested, a synergy between amoxicillin and ceftriaxone was observed in 14 (93%) according to minimal inhibitory concentration strips and 12 (80%) per...
Among 15 strains of tested, a synergy between amoxicillin and ceftriaxone was observed in 14 (93%) according to minimal inhibitory concentration strips and 12 (80%) per the checkerboard methods, as well as for 2 of the 3 strains tested by the time-killing curve. This association may be an alternative treatment for listeriosis in the future.
PubMed: 38835495
DOI: 10.1093/ofid/ofae295 -
Revista Argentina de Microbiologia Jun 2024Human listeriosis is an infectious disease caused by Listeria monocytogenes. The invasive form of this disease leads to a high rate of hospitalizations and fatality. The...
Human listeriosis is an infectious disease caused by Listeria monocytogenes. The invasive form of this disease leads to a high rate of hospitalizations and fatality. The main mode of transmission is through contaminated ready-to-eat foods such as dairy, vegetables and meat products. The knowledge of the diversity and population dynamics of isolates collected from human and food sources is essential for the detection of clusters and the identification of common sites of infection. The aim of this study was the molecular characterization of L. monocytogenes isolates in Argentina. We sequenced a total of 63 isolates, 35 from human and 28 from food sources, collected between 2018 and 2023. Our genomic study divided the isolates into two lineages, four serogroups, 17 sequence types and 15 clonal complexes (CCs). The hypervirulent clone CC1 (lineage I; serogroup IVb) predominated in human and food samples. The phylogenomic analysis showed a high and possible epidemiological relationship between isolates from human and/or food sources, suggesting the presence of transmission chains in our country. These findings highlight the need to strengthen genomic surveillance of L. monocytogenes in Argentina. The identification of geographic distribution and characteristics of predominant and emerging clones from human and food sources might help to focus action plans and public health policies better directed at the control and prevention of listeriosis.
PubMed: 38834434
DOI: 10.1016/j.ram.2024.03.002