Superparamagnetic Iron Oxide Nanoparticles Decorated Mesoporous Silica Nanosystem for Combined Antibiofilm Therapy

A crucial challenge to face in the treatment of biofilm-associated infection is the ability of bacteria to develop resistance to traditional antimicrobial therapies based on the administration of antibiotics alone. This study aims to apply magnetic hyperthermia together with controlled antibiotic delivery from a unique magnetic-responsive nanocarrier for a combination therapy against biofilm. The design of the nanosystem is based on antibiotic-loaded mesoporous silica nanoparticles (MSNs) externally functionalized with a thermo-responsive polymer capping layer, and decorated in the outermost surface with superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs are able to generate heat upon application of an alternating magnetic field (AMF), reaching the temperature needed to induce a change in the polymer conformation from linear to globular, therefore triggering pore uncapping and the antibiotic cargo release. The microbiological assays indicated that exposure of E. coli biofilms to 200 µg/mL of the nanosystem and the application of an AMF (202 kHz, 30 mT) decreased the number of viable bacteria by 4 log10 units compared with the control. The results of the present study show that combined hyperthermia and antibiotic treatment is a promising approach for the effective management of biofilm-associated infections.

A Novel 3D Titanium Surface Produced by Selective Laser Sintering to Counteract Streptococcus oralis Biofilm Formation

The topography of implant surfaces influences the interaction relationship between material and bacteria. The aim of this work was to characterize a novel 3D titanium surface, produced using Selective Laser Sintering (SLS), and to compare the bacterial interaction with machined and double acid etching (DAE) discs. The surface was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and Energy Dispersive X-ray Spectrometry (EDX). The wettability was measured using the sessile method. The microbiological investigation consisted in the cultivation of a bacterial pioneer, Streptococcus oralis, on titanium surfaces, previously covered by human saliva in order to form the acquired pellicle. Then, colony forming units (CFUs), biofilm biomass quantification, analyses of viable and dead cells, and SEM observation were determined after 24 h of S. oralis biofilm formation on the different discs. A significantly higher nano-roughness with respect to the other two groups characterized the novel 3D surface, but the wettability was similar to that of machined samples. The microbiological assays demonstrated that the 3D discs reported significantly lower values of CFUs and biofilm biomass with respect to machined surfaces; however, no significant differences were found with the DAE surfaces. The live/dead staining confirmed the lower percentage of living cells on DAE and 3D surfaces compared with the machined. This novel 3D surface produced by SLS presented a high antiadhesive and antibiofilm activity.

Microbiological, sensory, and physicochemical quality of curd cheeses originating from direct sales

Background and Aim: Curd cheeses are characteristic elements of the dairy assortment, mainly in Central and Eastern European countries, and constitute a numerous and diverse group of dairy products. The aim of the study was to assess the physicochemical, microbiological, and sensory quality of curd cheeses available in marketplaces in Lublin, where they were purchased through direct sales from producers. Materials and Methods: The research material was household-produced curd cheese purchased 4 times (at 2-week intervals) from three producers. The physicochemical parameters (i.e., the total protein and fat content, active acidity, and titratable acidity) were determined in the cheeses. Microbiological assays were performed to evaluate the total number of bacteria (on milk agar), the number of yeasts and molds (on Sabouraud medium), and the number of coliform bacteria (on MacConkey medium). A general sensory evaluation was performed by a five-person panel, who assessed the appearance and color, texture, flavor, and aroma of the samples. Results: The cheeses exhibited significant differences in their protein and fat contents, but these values were within the allowable limits. Most of the evaluated cheeses had normal levels of active and titratable acidity; substantially lower titratable acidity and higher pH values were detected only in the samples from supplier A. The total number of bacteria in the curd cheese samples was high (3.2×108 colony-forming units [cfu]×g-1 cheese) and varied substantially (from 3.6×107 to 8.6×108 cfu×g-1). The growth of Gram-negative bacterial colonies on MacConkey medium was observed in the samples from suppliers B and C (5.5×103 and 1.7×104 cfu×g-1, respectively), which is an undesirable phenomenon. The number of colonies cultured on Sabouraud medium and identified as yeast-like microorganisms ranged from 1.8×104 (product from supplier A) to 4.9×105 cfu×g-1 (cheese from supplier C). The scores in the sensory evaluation of the tested curd cheeses were low. The highest mean scores were achieved for appearance and color (4.25-4.45 points). Conversely, flavor and aroma received the lowest score (3.17 points). The highest scores for both the overall assessment and each parameter separately were awarded to the curd cheese produced by supplier A. Conclusion: Our results suggest poor hygienic conditions during milk collection and processing, as well as during the distribution of these dairy products. Altogether, the purchase of products from direct sales may be associated with risks related to poor consumer health and food quality.

Epidemiology of Asymptomatic Bacteriuria among diabetic patients in Tikrit City, Iraq

Objectives: This study aimed to show the Epidemiology of Asymptomatic Bacteriuria among diabetic patients in Tikrit City, Iraq. Methods: A cross sectional study was conducted in Tikrit city among diabetic and non-diabetic patients from General Salahalddin Hospital and from outpatient clinics. This study conduct 270 persons, including 155 diabetes sufferers and 115 non-diabetics. Consented subjects had their mid-stream urine collected, and each sample was examined using microscopy and culture techniques. Standard microbiological assays to determine the presence of pus cells and bacteria in urine were used to identify isolates. Results: Asymptomatic Bacteriuria (ASB) was found in 21.5 % of subjects, with diabetics having 26.4 % and non-diabetics having 14.8 %. ASB is higher in the age group above 51 years 29 (50%), Females 51 (88%) demonstrated a higher prevalence than males 7(12%) in both diabetic and non-diabetic groups. Staphylococcus epidermidis was the most common bacterium isolated from urine in both diabetics and non-diabetics (22.4 %). Other bacterium isolates included E. coli (19%) , Enterococcus fecalis (13.7%), Klebsiella pneumonia (12%), and Enterobacter sp (12%), Staph aureus (10.3%), Staph saprophyticus (6.8%), Pseudomonas aerogenosa (3.4%). The most of isolated microorganisms were resistance to gentamycin, trimethoprim and cefotrixone. Levofloxacin and ciprofloxacin were the most sensitive to uropathogens caused by bacteria . Conclusion: Diabetic sufferers had a higher prevalence of ASB (26.4%) than non-diabetics, according to the study (14.8 %). The majority of ASB was caused by Staphylococcus sp, indicating a shift in the aetiologic spectrum. The majority of isolates demonstrated multiple resistance in both diabetics and non-diabetics, indicating the necessity to increase antibiotic sensitization in Tikrit.

COMPARISON AND EVALUATION OF PHARMACOPOEIAL METHODS FOR THE ASSESSMENT OF POTENCY OF ANTIBIOTICS

The detection and assessment of potency of antibiotics are crucial for the pharmaceutics. The valid methods for microbiological assays in pharmacopoeias are mainly based on statistical comparison of the data obtained by measuring the cidal activity resulting from the treatment of the antibiotic active ingredient in the composition of the pharmaceutics with the target microorganism. However, it was seen that there is no validated microbiological method for some active ingredients. Due to microbiological assays are indispensable methods for determining the potency of some active ingredient groups, the calculation of the potency is performed logarithmically. In either turbidimetric or chromatographic methods, the statistical evaluation of the sample is compared with the standard reference material. Analysis data obtained by chromatographic and chemical methods are linear peak areas and spectrophotometer readings. In microbiological methods, the data obtained from the analyzes performed to determine the potency of antibiotics are the inhibition zone diameters or turbidimetric turbidity data. In this study, above-mentioned microbiological assays are compared in the context of the main pharmacopoeias EP, USP, CP, IP and BP, and evaluated in terms of the chromatographic method and classical microbiological method. It has been observed that chromatographic and chemical methods are not available to determine the potency of some pharmaceutical products containing antibiotics. The examinations made reveal the difficulty of analyzing some active ingredient groups according to chemical and chromatographic methods. For this reason, the importance of method validation studies is increasing in order to analyze active substances that do not have alternative analysis methods with microbiological and chemical methods. In this study, all validated microbiological methods were investigated, and it was aimed to determine alternative methods to chromatographic and chemical methods. It was concluded that the realization of new microbiological methods to be validated by evaluating the methods in all differences would facilitate the study. Peer Review History: Received: 18 May 2021; Revised: 15 June; Accepted: 28 June, Available online: 15 July 2021 Academic Editor: Dr. Asia Selman Abdullah, Al-Razi university, Department of Pharmacy, Yemen, [email protected] UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.5/10 Average Peer review marks at publication stage: 7.5/10 Reviewer(s) detail: Dr. Iman Muhammad Higazy, National Research Center, Egypt, [email protected] Dr. George Zhu, Tehran University of Medical Sciences, Tehran, Iran, [email protected] Similar Articles: AN OVERVIEW ON PHARMACOPOEIAS IN THE WORLD AND MONOGRAPH ELABORATION TECHNIQUES

Spatial and Seasonal Structure of Bacterial Communities Within Alpine Vineyards: Trentino as a Case Study.

Bacterial microbiota has a fundamental role in determining the fitness of a grapevine, the composition of grapes and the features of wines but, at present, little information is available. In this work, the bacterial microbiota that colonizes the different portions of a grapevine (bark, leaves and grapes) was explored in the vineyards of the Alpine region of Trentino, considering the impact of different environmental and agronomical variables. The six vineyards included in the work were identified considering different geographical positions, vine training systems and agronomical approaches, to explore the whole variability of the vine ecosystem. Moreover, the surface amount of copper was measured on grapes and leaves during the vegetative growth, to test its relation with microbiota development. Microbiological assays, performed using plate counts and Illumina MiSeq, started in May until October revealing an increase in the concentration of grape microbiota proportional to the ripening. Conversely, the peak of bacterial concentration onto leaves and bark occurred in August, probably due to the more favorable environmental conditions. In bark samples, the microbiota reached the 7 log UFC/cm2, while 6 log UFC/g were measured in grape samples. A remarkable biodiversity was observed, with 47 genera/species of bacteria present. The presence of the main microbial groups (Alphaproteobacteria, Desulfovibrionaceae, Clostriadiales, Oscillospira, Lachnospiraceae and Bacteroidales) was ubiquitous in vineyards, but differences in terms of relative abundance were observed according to the period, altitude of vineyard and training system. Bacteria having oenological implication (Lactobacillus, Pediococcus and Oenococcus) were detected only in grape samples collected in August. The data revealed a complex bacterial ecosystem inside the vineyard that, while maintaining common traits, evolves according to environmental and agronomical inputs. This study contributes to define the role of bacteria in the complex balance established in each vineyard between human actions and agricultural environment, known as terroir.

The Implication of Vibrio Bacteria in the Winter Mortalities of the Critically Endangered Pinna nobilis

Pinna nobilis populations, constituting the largest bivalve mollusk endemic to the Mediterranean, is characterized as critically endangered, threatened by extinction. Among the various factors proposed as etiological agents are the Haplosporidium pinnae and Mycobacterium sp. parasites. Nevertheless, devastation of the fan mussel populations is still far from clear. The current work is undertaken under a broader study aiming to evaluate the health status of Pinna nobilis population in Aegean Sea, after the mass mortalities that occurred in 2019. A significant objective was also (a) the investigation of the etiological agents of small-scale winter mortalities in the remaining populations after the devastating results of Haplosporidium pinnae and Mycobacterium sp. infections, as well as (b) the examination of the susceptibility of the identified bacterial strains in antibiotics for future laboratory experiments. Microbiological assays were used in order to detect the presence of potential bacterial pathogens in moribund animals in combination with molecular tools for their identification. Our results provide evidence that Vibrio bacterial species are directly implicated in the winter mortalities, particularly in cases where the haplosporidian parasite was absent. Additionally, this is the first report of Vibrio mediterranei and V. splendidus hosted by any bivalve on the Greek coastline.

Proposals for Antimicrobial Testing Guidelines Applied on Ajowan and Spanish Lavender Essential Oils

To fight the rising resistance of microorganisms to antibiotics, a strategy followed by several researchers is to focus on natural compounds, such as essential oils, as a source of potent antibacterial compounds. These last decades, hundreds of original papers have been written about microbiological assays that prove the antibacterial activity of essential oils and their use in the medical field. But can we really compare all the data available in the literature when the raw material, the microbiological assays, and/or the strains are different from one article to another? This review will point out the differences and the inadequate practices found in published articles that tested 2 lesser-studied essential oils–Spanish lavender and the ajowan–by the broth dilution method against Staphylococcus aureus, a human pathogenic bacterium. Many pitfalls were found in the literature, for example, a variable chemical composition rarely underlined by the authors, unidentified strains or clinical strains used without a related antibiogram, a lack of quality controls, and the assertion of questionable positive results. At last, some general guidelines that should be followed by every scientific researcher will be discussed.

Antimicrobial Effect of Nano-Silver Against Oral Streptococci: Implications in Containment of Bacterial Biofilm on Orthodontal Appliances

Among various metal-based nanoparticles, silver nanoparticles (AgNPs) manifest superior inhibitory effect against several microorganisms. In fact, the AgNPs based therapy has been reported to inhibit both sensitive as well resistant isolates of bacteria and other disease causing microbes with equal propensity. Keeping this fact into consideration, we executed bio-mediated synthesis of AgNPs employing Hibiscus rosa sinensis flower extract. The as-synthesized AgNPs were evaluated for their potential to inhibit Streptococcus mutans (S. mutans), one of the main causative bacteria for dental caries. Beside several other reasons, orthodontic appliances have also been reported to facilitate infliction of oral cavity with a range of microbes including S. mutans. To determine the growth inhibitory and anti-adherence activity of AgNPs on orthodontic appliance, we performed microbiological assays employing AgNPs adsorbed on to the orthodontic wires. Topographic analysis of orthodontic wires was executed by scanning electron microscopy. In addition to antimicrobial and antibiofilm activity against oral S. mutans, the as-fabricated AgNPs demonstrated significant inhibitory and anti-biofilm properties against other biofilm forming bacteria such as Escherichia coli and Listeria monocytogenes as well.

Pseudomonas aeruginosa Biofilm Lung Infection in Cystic Fibrosis: The Challenge of Persisters

Pseudomonas aeruginosa lung infection is difficult to eradicate due to the multiple (intrinsic and acquired) antibiotic resistance of bacteria and to their ability to produce a thick biofilm. Antibiotic treatment is hampered by poor antibiotic diffusion, efflux pump overexpression and the development of a persistent subpopulation with low metabolic activity. This is a cause for special concern in Cystic Fibrosis (CF) patients, where P. aeruginosa lung infection is the chief cause of morbidity and mortality. Combined tobramycin-ciprofloxacin treatment is routinely adopted due to the low frequency of resistant strains and its ostensible ability to control the infection. Nevertheless, symptoms usually recur, mainly due to the antibiotic persisters, which are difficult to detect in routine cultural microbiological assays. This chapter describes the issues involved in the microbiological diagnosis of P. aeruginosa lung infection in CF patients and the possible role of subinhibitory antibiotic concentrations in persister development and infection recurrence.