Target Microorganisms Research Articles

Bactericidal and bacteriostatic effects of sodium polyphosphate emulsifying salts on selected targets in processed cheese

Processed cheeses (PC) are products with extended shelf-lives, they have in their composition such additives as emulsifying salts and preservatives. Emulsifying salts are used due their desirable emulsification properties, however, little is known about their inhibitory activity against microorganisms that can survive and multiply in these products; jeopardizing cheese quality or even posing as hazards to consumers. The aim is to determine how mixtures of emulsifying salts (ESSP: emulsifying salt composed of short polyP; BSLP: bacteriostatic salt composed of long polyP; and trisodium citrate) can influence the microbial populations in PC during 90 days of storage. A total of 14 treatments (T1 - T14) were evaluated against eight target strains (Bacillus cereus INV 10(3); Bacillus subtilis ATCC 19659; Bacillus thuringiensis CFBP 3476; Clostridium perfringens ATCC 13124; Enterococcus faecalis FAIR-E 179; Listeria monocytogenes Scott A; Pseudomonas fluorescens 07A; and Staphylococcus aureus ATCC 6538) inoculated into PC. A treatment composed of emulsifying salts without antimicrobial effect (ESSP 1.5%) was considered as the positive growth control, and another treatment composed of antimicrobial additives (nisin and potassium sorbate) was considered as the negative growth control. Bacterial growth was analyzed using ANOVA and Tukey (p < 0.05), based on selected treatment grouping. Most treatments resulted in some level of bactericidal or bacteriostatic effect against the target microorganisms. Bactericidal activity was evident against Bacillus spp., and bacteriostatic effect was clear against C. perfringens, E. faecalis, L. monocytogenes and S. aureus (p < 0.05) during the storage period. T13, composed of 1.5% BSLP, presented results comparable to those observed for the negative control for bacterial inhibition in PC samples during 90 days of storage. T13 was able to reduce the B. cereus INV 10(3) and B. thuringiensis CFBP 3476 population more than the negative control (p < 0.001), as well as present better results for the inhibition of C. perfringens ATCC 13124 and L. monocytogenes Scott A by the end of storage. The performance of the negative control was better than T13 only against S. aureus - ATCC 6538 (p < 0.001). Taken together, the results contribute to expanding the understanding of emulsifying salt application in PC, with a focus on microbiological safety and shelf-life.

Pre-isolation Molecular Screening for High-throughput Sampling and Sequencing of Bacterial Microbes from the Environment.

Environmental studies often require culture and characterization to understand the prevalence, distribution, persistence and functions of target microorganisms in ecological habitats. Isolating pure microbiological monocultures allows the phenotypic characterization of microorganisms to study their functional properties. For efficient isolation of low-prevalence organisms, enrichment followed by PCR screening is performed to identify positive samples for subsequent culture. Molecular characterization, strain-typing, and genotyping of isolated microorganisms is best comprehensively performed using whole-genome sequencing. This article outlines end-to-end protocols for screening, isolation, and sequencing of microbes from environmental samples. We provide systematic methods for environmental study design, enrichment, screening, and isolation of target microorganisms. Species identification is performed using qPCR or MALDI-TOF MS. Genomic DNA is extracted for whole-genome sequencing using the Oxford Nanopore platform. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Designing and conducting an environmental soil sampling study Basic Protocol 2: Enrichment of microbes from environmental soil samples Alternate Protocol 1: Collection and enrichment of microbes from environmental water samples Basic Protocol 3: Screening of enriched samples by direct qPCR Basic Protocol 4: Enumeration and isolation of enriched samples using selective medium Basic Protocol 5: Species confirmation using colony qPCR Alternate Protocol 2: Species identification using a MALDI-TOF MS Biotyper Alternate Protocol 3: Species identification of bacterial isolates using universal PCR primers and Sanger sequencing Basic Protocol 6: Cryostorage of bacterial isolates Basic Protocol 7: Extraction of genomic DNA Basic Protocol 8: Quality check of extracted genomic DNA Basic Protocol 9: Whole-genome sequencing using the Oxford Nanopore MinION Platform.

Isolation, identification and comparative analysis of 16S rRNA of Multidrug-resistant Bacteria Clinically isolated from Al Qassim Region Hospitals in Saudi Arabia

Objective: This study concluded that the antibiotic resistance and gene transfer across bacterial strains in the hospital setting are two possible explanations for the observed sequence changes in the target microorganisms.&#x0D; Methods: The 16S rDNA genes of all isolates were effectively amplified using PCR, and detailed identification results were derived from GenBank databases. The BLAST search resulted in the classification of 28 isolates into five strains. The GC content of bacterial sequences varies greatly between single species.&#x0D; Results: 16S rDNA was utilized to identify bacterial species from isolates strains results demonstrated that identification of bacterial strains. Sequences varied between and within strains, also, variation are noticed in genomic nucleotide content of isolated and identified strains. Results of the present study demonstrated that the observed heterogeneity in the sequences of our target bacterial strains may be linked to antibiotic resistance and gene transfer between bacteria that evolved as a result of the hospital environment.&#x0D; Conclusion: This study concluded that antibiotic-resistant bacteria are capable of transferring copies of their DNA encoding a resistance mechanism to other bacteria, even those that are distantly related to them. the observed heterogeneity in the sequences of our target bacterial strains may be linked to antibiotic resistance and gene transfer between bacteria that evolved as a result of the hospital environment.

Sous-vide processing of silver carp: Effect of processing temperature and cold storage duration on the microbial quality of the product as well as modeling by artificial neural networks.

Silver carp (Hypophthalmichthys molitrixi) was processed by sous-vide method at different temperatures (60, 65, 70, and 75°C). Then, the microbiological quality of the processed samples was monitored during cold storage (4°C) for 21 days. The target microorganisms were Enterobacteriaceae, Lactic Acid bacteria (LAB), Pseudomonas, Psychrotrophs, and total viable count (TVC). In samples processed at 75°C, the presence of Enterobacteriaceae, Pseudomonas and Psychrotrophs were not detectable up to 15 days of storage and lactic acid bacteria were not detectable even at the end of the storage period. A radial basis function neural network (RBFNN) model was established to predict the changes in the microbial content of silver carp. In this step, the relationship between processing temperature and storage duration on microbial growth was modeled by ANNs (artificial neural networks). The optimal ANN topology for modeling Enterobacteriaceae, Pseudomonas, and Psychrotroph contained 9 neurons in the hidden layer, but it contained 15 and 14 neurons for TVC and LAB, respectively. By experimenting with the temperature of -80°C, it was revealed that the obtained ANN model has a high potential for prediction.

Superiority of UV222 radiation by in situ aquatic electrode KrCl excimer in disinfecting waterborne pathogens: Mechanism and efficacy

Microbial safety in water has always been the focus of attention, especially during the COVID-19 pandemic. Development of green, efficient and safe disinfection technology is the key to control the spread of pathogenic microorganisms. Here, an in situ aquatic electrode KrCl excimer radiation with main emission wavelength 222 nm (UV222) was designed and used to disinfect model waterborne virus and bacteria, i.e. phage MS2, E. coli and S. aureus. High inactivation efficacy and diversity of inactivation mechanisms of UV222 were proved by comparision with those of commercial UV254. UV222 could totally inactivate MS2, E. coli and S. aureus with initial concentrations of ∼107 PFU or CFU mL−1 within 20, 15, and 36 mJ/cm2, respectively. The UV dose required by UV254 to inactivate the same logarithmic pathogenic microorganism is at least twice that of UV222. The protein, genomic and cell membrane irreparable damage contributed to the microbial inactivation by UV222, but UV254 only act on nucleic acid of the target microorganisms. We found that UV222 damage nucleic acid with almost the same or even higher efficacy with UV254. In addition, free base damage of UV222 in similar ways with UV254(dimer and hydrate). But due to the quantum yield of free base degradation of UV222 was greater than UV254, the photolysis rates of UV222 to A, G, C and U four bases were 11.5, 1.2, 3.2 and 1 times as those of UV254, respectively. Excellent disinfection performance in UV222 irradiation was also achieved in real water matrices (WWTP and Lake). In addition, it was proved that coexisting HCO3- or HPO42 – in real and synthetic water matrices can produce • OH to promote UV222 disinfection. This study provided novel insight into the UV222 disinfection process and demonstrated its possibility to take place of the conventional ultraviolet mercury lamp in water purification.

Liposomal Antibiotics for the Treatment of Infectious Diseases

Liposomal delivery systems have been utilized in developing effective therapeutics against cancer and targeting microorganisms in and out of host cells and within biofilm community. The most attractive feature of liposome-based drugs are enhancing therapeutic index of the new or existing drugs while minimizing their adverse effects. This communication provides an overview on several aspects of liposomal antibiotics including the most widely used preparation techniques for encapsulating different agents and the most important characteristic parameters applied for examining shape, size and stability of the spherical vesicles. In addition, the routes of administration, liposome--cell interactions and host parameters affecting the bio distribution of liposomes are highlighted. Liposomes are safe and suitable for delivery of variety of molecules and drugs in biomedical research and medicine. They are known to improve the therapeutic index of encapsulated agents and reduce drug toxic- ity. Recent studies on liposomal formulation of chemotherapeutic and bioac- tive agents and their targeted delivery show liposomal antibiotics potential in the treatment of microbial infections.

Validation of High-Pressure Homogenization Process to Pasteurize Brazil Nut (Bertholletia excelsa) Beverages: Sensorial and Quality Characteristics during Cold Storage

The effect of high-pressure homogenization (HPH) on the inactivation of Escherichia coli and the stability of the quality properties of Brazil nut beverages were studied. E. coli was used as target microorganism to validate the HPH process (pressures from 50 to 180 MPa and inlet temperatures (Ti) from 25 to 75 °C). Cold storage (5 °C) for 21 days was conducted to establish the shelf-life of BN beverages, in terms of their microbiological, physical, physicochemical, and sensorial stability. HPH-treated samples were compared to pasteurized BN beverages (63 °C for 20 min). The combination of Ti and the pressure of the HPH process (50 to 150 MPa/75 °C and 180 MPa/25 °C) had a significant effect on E. coli inactivation (8.2 log CFU/mL). During storage at 5 °C, the growth of mesophilic aerobes in processed BN beverages was controlled by the HPH process. Oxidative stability (TBAR assay) and physicochemical properties (pH, acidity, and °Brix) were evaluated during cold storage, showing good stability. Additionally, HPH-treated beverages showed a reduction in their particle size and the formation of more stable protein aggregates, which favored the beverages’ whiteness (color). The HPH process could be an alternative to pasteurization to obtain Brazil nut beverages with an acceptable microbiological shelf life (≥21 days at 5 °C) and high-quality characteristics without the use of any additives.

Bacteriophage-based techniques for elucidating the function of zebrafish gut microbiota.

Bacteriophages (or phages) are unique viruses that can specifically infect bacteria. Since their discovery by Twort and d'Herelle, phages with bacterial specificity have played important roles in microbial regulation. The intestinal microbiota and host health are intimately linked with nutrient, metabolism, development, and immunity aspects. However, the mechanism of interactions between the composition of the microbiota and their functions in maintaining host health still needs to be further explored. To address the lack of methodology and functions of intestinal microbiota in the host, we first proposed that, with the regulations of special intestinal microbiota and applications of germ-free (GF) zebrafish model, phages would be used to infect and reduce/eliminate the defined gut bacteria in the conventionally raised (CR) zebrafish and compared with the GF zebrafish colonized with defined bacterial strains. Thus, this review highlighted the background and roles of phages and their functional characteristics, and we also summarized the phage-specific infection of target microorganisms, methods to improve the phage specificity, and their regulation within the zebrafish model and gut microbial functional study. Moreover, the primary protocol of phage therapy to control the intestinal microbiota in zebrafish models from larvae to adults was recommended including phage screening from natural sources, identification of host ranges, and experimental design in the animal. A well understanding of the interaction and mechanism between phages and gut bacteria in the host can potentially provide powerful strategies or techniques for preventing bacteria-related human diseases by precisely regulating in vitro and in vivo, which will provide novel insights for phages' application and combined research in the future. KEY POINTS: • Zebrafish models for clarifying the microbial and phages' functions were discussed • Phages infect host bacteria with exquisite specificity and efficacy • Phages can reduce/eliminate the defined gut bacteria to clarify their function.

The effect of tailing lipidation on the bioactivity of antimicrobial peptides and their aggregation tendency

AbstractAntimicrobial peptides (AMPs) are potentially powerful alternatives to conventional antibiotics in combating multidrug resistance, given their broad spectrum of activity. They mainly interact with cell membranes through surface electrostatic potentials and the formation of secondary structures, resulting in permeability and destruction of target microorganism membranes. Our earlier work showed that two leading AMPs, MSI‐78 (4–20) and pardaxin (1–22), had potent antimicrobial activity against a range of bacteria. It is known that the attachment of moderate‐length lipid carbon chains to cationic peptides can further improve the functionality of these peptides through enhanced interactions with the membrane lipid bilayer, inducing membrane curvature, destabilization, and potential leakage. Thus, in this work, we aimed to investigate the antimicrobial activity, oligomerization propensity, and lipid‐membrane binding interactions of a range of N‐terminal lipidated analogs of MSI‐78 (4–20) and pardaxin (1–22). Molecular modeling results suggest that aggregation of the N‐lipidated AMPs may impart greater structural stability to the peptides in solution and a greater depth of lipid bilayer insertion for the N‐lipidated AMPs over the parental peptide. Our experimental and computational findings provide insights into how N‐terminal lipidation of AMPs may alter their conformations, with subsequent effects on their functional properties in regard to their self‐aggregation behavior, membrane interactions, and antimicrobial activity.

Differential analysis of culturable and unculturable subgingival target microorganisms according to the stages of periodontitis

ObjectivesCulturable and unculturable microorganisms have been associated with periodontitis. Their differential proportions and composition have not been evaluated by their severity and complexity defined by stages in the 2018 AAP-EEP classification.MethodsOne hundred eighty subgingival biofilm samples were collected in Spain and Colombia from subjects categorized as health/gingivitis: periodontitis stages I/II periodontitis stages III/IV. Target culturable microorganisms (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, and Eubacterium nodatum) and target unculturable microorganisms (Filifactor alocis, Eubacterium saphenum, Eubacterium brachy, Desulfobulbus oralis) were evaluated by quantitative PCR analysis. In addition, their differences and association with periodontal status were analyzed by ANCOVA and logistic regression models once adjusted to age, current smoking, and country.ResultsP. gingivalis was significantly associated with periodontitis stages I/II, OR 2.44 (CI 95% 1.08–5.47) and stages III/V, OR 6.43 (CI 95% 2.43–16.9). T forsythia, OR 7.53 (CI 95% 2.07–27.4); D. oralis, OR 5.99 (CI 95% 2.71–13.23); F. alocis, OR 10.9 (CI 95% 4.56–23.2); E. brachy, 3.57 (CI 95% 1.40–9.11); and E. saphenum, 4.85 (CI 95% 1.99–11.7) were significantly associated only with stages III/IV periodontitis. P. gingivalis evidenced significant differences with the increase in the severity of the periodontal lesion: 2.97 colony forming unit (CFU)/μL (CI 95% 2.32–3.54) health/gingivitis, and 4.66 CFU/μL (CI 95% 4.03–5.30) and 5.90 CFU/μL (CI 95% 5.20–6.48) in stages I/II and III/IV respectively (p < 0.0001). Unculturable microorganisms only evidenced differences in concentration in stages III/IV compared with health-gingivitis (p ≤ 0.001).ConclusionCulturable and unculturable are strongly associated with stages III/IV periodontitis. Classic culturable microorganisms are more sensitive to differentiate between stages of periodontitis in the quantitative analysis.Clinical relevanceFuture interventional studies of periodontal disease should include Filifactor alocis, Eubacterium saphenum, Eubacterium brachy, and Desulfobulbus oralis as possible markers of therapy response and as indicators of progressive disease.

Generalizability of Soft Sensors for Bioprocesses through Similarity Analysis and Phase-Dependent Recalibration.

A soft sensor concept is typically developed and calibrated for individual bioprocesses in a time-consuming manual procedure. Following that, the prediction performance of these soft sensors degrades over time, due to changes in raw materials, biological variability, and modified process strategies. Through automatic adaptation and recalibration, adaptive soft sensor concepts have the potential to generalize soft sensor principles and make them applicable across bioprocesses. In this study, a new generalized adaptation algorithm for soft sensors is developed to provide phase-dependent recalibration of soft sensors based on multiway principal component analysis, a similarity analysis, and robust, generalist phase detection in multiphase bioprocesses. This generalist soft sensor concept was evaluated in two multiphase bioprocesses with various target values, media, and microorganisms. Consequently, the soft sensor concept was tested for biomass prediction in a Pichia pastoris process, and biomass and protein prediction in a Bacillus subtilis process, where the process characteristics (cultivation media and cultivation strategy) were varied. High prediction performance was demonstrated for P. pastoris processes (relative error = 6.9%) as well as B. subtilis processes in two different media during batch and fed-batch phases (relative errors in optimized high-performance medium: biomass prediction = 12.2%, protein prediction = 7.2%; relative errors in standard medium: biomass prediction = 12.8%, protein prediction = 8.8%).

A strategy for addicting transgene-free bacteria to synthetic modified metabolites.

Biological containment is a safeguard technology to prevent uncontrolled proliferation of "useful but dangerous" microbes. Addiction to synthetic chemicals is ideal for biological containment, but this currently requires introduction of transgenes containing synthetic genetic elements for which environmental diffusion has to be prevented. Here, I designed a strategy for addicting transgene-free bacteria to synthetic modified metabolites, in which the target organism that can neither produce an essential metabolite nor use the extracellularly supplied metabolite, is rescued by a synthetic derivative that is taken up from a medium and converted into the metabolite in the cell. Because design of the synthetic modified metabolite is the key technology, our strategy differs distinctly from conventional biological containment, which mainly depends on genetic manipulation of the target microorganisms. Our strategy is particularly promising for containment of non-genetically modified organisms such as pathogens and live vaccines.

A Review of the Efficacy of Ultraviolet C Irradiation for Decontamination of Pathogenic and Spoilage Microorganisms in Fruit Juices.

Ultraviolet C (UV-C, 200-280 nm) light has germicidal properties that inactivate a wide range of pathogenic and spoilage microorganisms. UV-C has been extensively studied as an alternative to thermal decontamination of fruit juices. Recent studies suggest that the efficacy of UV-C irradiation in reducing microorganisms in fruit juices is greatly dependent on the characteristics of the target microorganisms, juice matrices, and parameters of the UV-C treatment procedure, such as equipment and processing. Based on evidence from recent studies, this review describes how the characteristics of target microorganisms (e.g., type of microorganism/strain, acid adaptation, physiological states, single/composite inoculum, spore, etc.) and fruit juice matrices (e.g., UV absorbance, UV transmittance, turbidity, soluble solid content, pH, color, etc.) affect the efficacy of UV-C. We also discuss the influences on UV-C treatment efficacy of parameters, including UV-C light source, reactor conditions (e.g., continuous/batch, size, thickness, volume, diameter, outer case, configuration/arrangement), pumping/flow system conditions (e.g., sample flow rate and pattern, sample residence time, number of cycles), homogenization conditions (e.g., continuous flow/recirculation, stirring, mixing), and cleaning capability of the reactor. The collective facts indicate the immense potential of UV-C irradiation in the fruit juice industry. Existing drawbacks need to be addressed in future studies before the technique is applicable at the industrial scale.

Nationwide Results of Microorganism Antigen Testing as a Component of Preoperative Synovial Fluid Analysis.

Antigen immunoassays to detect synovial fluid (SF) microorganisms have recently been made available for clinical use. The purpose of this study was to determine the sensitivity and specificity of an SF microorganism antigen immunoassay detection (MID) panel, evaluate the panel's capability to detect microorganisms in the setting of culture-negative periprosthetic joint infection (PJI), and determine diagnostic predictive values of the MID panel for PJI. This study included 67,441 SF samples obtained from a hip or knee arthroplasty, from 2,365 institutions across the United States, submitted to 1 laboratory for diagnostic testing. All data were prospectively compiled and then were analyzed retrospectively. Preoperative SF data were used to classify each specimen by the International Consensus Meeting (2018 ICM) definition of PJI: 49,991 were not infected, 5,071 were inconclusive, and 12,379 were infected. The MID panel, including immunoassay tests to detect Staphylococcus, Candida, and Enterococcus, was evaluated to determine its diagnostic performance. The MID panel demonstrated a sensitivity of 94.2% for infected samples that yielded positive cultures for target microorganisms (Staphylococcus, Candida, or Enterococcus). Among infected samples yielding positive cultures for their respective microorganism, individual immunoassay test sensitivity was 93.0% for Staphylococcus, 92.3% for Candida, and 97.2% for Enterococcus. The specificity of the MID panel for samples that were not infected was 98.4%, yielding a false-positive rate of 1.6%. The MID panel detected microorganisms among 49.3% of SF culture-negative infected samples. For PJI as a diagnosis, the positive predictive value of the MID panel was 91.7% and the negative predictive value was 93.8%. Among MID-positive PJIs, 16.2% yielded a discordant cultured organism instead of that detected by the antigen test. SF microorganism antigen testing provides a timely adjunct method to detect microorganisms in the preoperative SF aspirate, yielding a low false-positive rate and enabling the detection of a microorganism in nearly one-half of SF culture-negative PJIs. Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Detection of post-harvest pathogens by loop-mediated isothermal amplification: a review

Postharvest losses, which occur between harvest and consumption of agricultural commodities, are major causes of food waste. Minimizing food loss helps provide nutritious food for animals and humans, and alleviate adverse environmental effects on food production. These losses are often related to the presence of postharvest pathogens, including fungi and bacteria, which typically start by infecting crops in the field as well as during postharvest chain. Control of these pathogens relies on development of tools that ensure their early and accurate detection. Among these is loop-mediated isothermal amplification (LAMP), a molecular method for pathogen detection. LAMP characteristics of rapidity, specificity and simplicity have encouraged development of a number of LAMP assays for detection of postharvest pathogens. Each LAMP assay allows to detect a specific genetic region of the target microorganism, which can be directly related to mycotoxin production, fungicide resistance and phytotoxicity. The LAMP amplicons are rapidly visualized, either at a specific timepoint, or in real-time by taking measurements throughout reaction, thereby necessitating less sophisticated facilities than those needed for PCR assays. In addition, many studies have developed simple protocols for the direct detection of pathogens on fresh produce. This paper explains the LAMP reaction, and its importance for postharvest detection of fungi and bacteria. Previous studies that have developed LAMP assays are also discussed.

Tannins-lignin mixed nanoformulations for improving the potential of neem oil as fungicide agent.

Sustainability and circular economy are increasingly pushing for the search of natural materials to foster antiparasitic treatments, especially in the case of economically relevant agricultural cultivations, such as grapevine. In this work, we propose to deliver neem oil, a natural biopesticide loaded into novel nanovectors (nanocapsules) which were fabricated using a scalable procedure starting from Kraft lignin and grapeseed tannins. The obtained formulations were characterized in terms of size and Zeta potential, showing that almost all the nanocapsules had size in the suitable range for delivery purposes (mean diameter 150-300nm), with low polydispersity and sufficient stability to ensure long shelf life. The target microorganisms were three reference fungal pathogens of grapevine (Botrytis cinerea, Phaeoacremonium minimum, Phaeomoniella chlamydospora), responsible for recurrent diseases on this crop: grey mold or berry rot by B. cinerea and diseases of grapevine wood within the Esca complex of diseases. Results showed that grapeseed tannins did not promote inhibitory effects, either alone or in combination with Kraft lignin. On the contrary, the efficacy of neem oil against P. minimum was boosted by more than 1-2 orders of magnitude and the parasite growth inhibition was higher with respect to a widely used commercial pesticide, while no additional activity was detected against P. chlamydospora and B. cinerea.

Indoor temperature, humidity, and microorganisms in traditional and modern houses in Japan

Microorganisms in our living environment may affect human health. Microbial suppression by air cleaners and disinfecting agents may provide protection from pathogenic materials. However, excessive microbial suppression can negatively affect human health; thus, an appropriate level of microbiome control is beneficial. It is not well understood how physical environmental conditions, such as temperature and relative humidity, and human lifestyles and behaviors affect indoor microorganisms. To understand the relationship between physical environmental conditions and microbial communities in the human living environment, we measured temperature and relative humidity and collected microbial samples in modern and traditional Japanese houses. In this study, bacteria and fungi were the target microorganisms. In both houses, the DNA concentration of microorganisms on floor surfaces was high when the average relative humidity of the room was high. The same tendency was observed for the beam and pillar surfaces in the traditional house. Although more careful consideration is needed for some indoor surfaces, such as storage ceilings and air conditioner outlets, seasonal changes in relative humidity and DNA concentrations of microorganisms on indoor surfaces exhibit some correlation.

Relation between the risk factors for the severity of denture stomatitis and quality of life of complete edentulous individuals: a cross-sectional study.

To assess the association between risk factors for developing denture stomatitis (DS) and oral health-related quality of life (OHRQoL) in complete denture wearers. Participants of both sexes, wearing complete dentures, were classified using the modified Newton classification for the absence or the severity of DS and allocated to groups Normal or zero, IA, IB, II, and III. Lifestyle, oral and denture history, and medication use were assessed using specific questionnaires; clinical parameters such as anatomical characteristics of support were evaluated with the Kapur classification; salivary flow (SF) was calculated by the volume of unstimulated saliva per minute; and microbial load was determined by counting colony forming units (CFU) of target microorganisms present in the biofilm collected from dentures and palate. OHIP-EDENT assessed the OHRQoL. Kendall's tau_b and Spearman tests were applied with a significance level of 5%. 184 patients (143 female and 41 male) aged 65.5 ± 6.8 years were evaluated. Positive correlations were found for sex (women; p=0.013, r=0.16), individuals who started to consume alcoholic beverages as a young adult (18-27 years) (p=0.008, r=0.22), CFU of Candida spp. (p<0.001, r=0.27 denture; p<0.001, r=0.31 palate); Candida albicans (p=0.004, r=0.22 denture; p=0.003, r=0.25 palate), and Candida glabrata (p=0.004, r=0.22 denture; p=0.001, r=0.27 palate). Moreover, negative correlations with DS were found for CFU of Staphylococcus spp. (p=0.004, r=-0.20 palate) and enterobacteria (p=0.002, r=-0.24 palate), as well as a negative correlation between SF (p=0.009, r=-0.193) and DS. The CFU of Staphylococcus spp. and enterobacteria on the palate significantly correlated with OHRQoL. Being female, consuming alcoholic beverages as a young adult, CFU of Candida spp., Candida albicans, Candida glabrata, and salivary flow may be the most significant risk factors for DS. The microbial load of Staphylococcus spp. and enterobacteria seems to influence the quality of life for complete denture wearers.

Nanoparticles in the Era of Antimicrobial Resistance

Antimicrobial resistance is currently a global crisis and is becoming a major issue for human health. The pharmaceutical industries' efforts to create novel therapeutic choices are being slowed down by the active bacterial resistance to traditional antibiotics. Consequently, the rise in infectious diseases caused by resistant bacteria is accompanied by two main issues. Firstly, there is a rise in antibiotic resistance. Secondly, there is a growing disparity between the discovery of new drugs and the rise in antimicrobial resistance. Different treatment strategies are now being in practice to treat bacterial infections, including targeting bacterial virulence factors, bacteriophage therapy, and alteration of the microbiome. Alternative therapeutic approaches are consequently receiving more consideration as traditional antibiotics grow less effective [1].&#x0D; The use of nanoparticles is one of the most promising ways for combating microbial drug resistance. Nitric oxide-releasing nanoparticles (NO NPs), chitosan-containing nanoparticles (chitosan NPs), and metal-containing nanoparticles are a few examples of nanoparticle types that use various ways to simultaneously fight against microorganisms. Nanoparticles can be used to overcome existing drug resistance mechanisms such as decreased drug absorption and increased drug efflux from the microbial cell, biofilm formation, and intrinsic resistance. Finally, antimicrobial drugs can be directed via nanoparticles to the site of infection, enabling greater therapeutic doses to be administered there and overcoming resistance. Antibodies directed against a specific antigen on the surface of the target microorganism can be coupled with nanoparticles. For instance, S. aureus can be killed with great specificity using nanoparticles linked with protein A antibodies [2].&#x0D; Nanoparticles' chemical structure enables longer binding, active targeting of antibiotics with surface functionalization at the target location, and defense against enzymes. As a result, reaching a larger antibiotic concentration in the cell eliminates the need for a higher dose, which reduces adverse effects. Antibiotic nanoparticle conjugates have been recognized by several scientists as a novel class of antibacterial drugs that can lessen the issue of multidrug resistance. Numerous nanoparticles with antimicrobial properties, such as silver, gold, zinc oxide, and titanium oxide, have been tested against microbial pathogens that are multidrug-resistant in conjunction with commercially available antibiotics or peptides [3].&#x0D; Widespread of infectious diseases caused by multiple resistant bacteria is increased day by day and pose a major threat to public health. Therefore, novel antimicrobial strategies are needed to combat the antimicrobial resistance. To reduce adverse effects, nanoparticles may be a preferable option for treating bacterial infections at very low concentrations.&#x0D;

Bacteria inhibition of platelet concentrates with and without pre-centrifugation metronidazole incorporation on aggregatibacter actinomycetemcomitans

Background: Local administration of antibiotics was one of many approaches for the management of localized periodontal infection with the advantages of smaller total dosage delivered into the pocket, avoiding systemic antibiotic side effects, and increasing the exposure of target microorganism to higher concentration. Incorporating antibiotics into platelet concentrates can be considered for local antibiotic administration.Method: The sample in this study used Aggregatibacter actinomycetemcomitans which was divided into 4 partitions on each plate. Each plate was applied with Platelets Rich Fibrin (PRF) and Injectable Platelet rich fibrin (I-PRF) incorporated with metronidazole pre-centrifugation and two negative controls (PRF and I-PRF without metronidazole). The observation was performed after 1 day and 7 days of incubation by measuring inhibition zone diameter using vernier caliper. The data were analyzed using two-way ANOVA followed by post-hoc LSD.Result: I-PRF with metronidazole had the highest bacteria inhibition compared with other groups (p<0,05) on incubation day 1 and 7; I-PRF and PRF with metronidazole showed higher bacteria inhibition compared with I-PRF and PRF without metronidazole (p<0,05).Conclusion: Aggregatibacter actinomycetemcomitans inhibition of PRF and I-PRF incorporated with metronidazole was greater compared to PRF and I-PRF without incorporating metronidazole, and A. actinomycetemcomitans inhibition of I-PRF incorporated with metronidazole was greater than PRF incorporated with metronidazole.