In vitro activity of essential oils against Pseudomonas aeruginosa isolated from infected hip implants

Multifactorial action of lavender and lavandin oils against filamentous fungi

AIMS

In this study, five essential oils (EOs) from different species of Lavandula hybrida abrialis, for Lavandula hybrida R.C., Lavandula hybrida 'super A', Lavandula hybrida 'super Z' and Lavandula vera and its hybrids Lavender were evaluated against 26 dust-isolated fungal strains from North Africa.

METHODS AND RESULTS

The composition of the different EOs was determined from volume to dry weight. The photochemical analyses were performed via gas chromatography (GC). The cytotoxic effect of five lavender EOs on human epithelial colorectal adenocarcinoma cells (Caco-2) cell line was done. A total of 26 strains of filamentous fungi including Aspergillus spp., Botrytis cinerea, Ceriporia spp., Fusarium spp. and Penicillium glabrum were isolated from sand dust samples via molecular diagnostic tool of PCR. Fungal strains with the lowest minimal lethal concentration (MLC) were Penicillium glabrum, Ceriporia spp. and a strain of Aspergillus spp.

CONCLUSIONS

More studies are needed to verify the activity of this EO against more different fungal species, and determine the active ingredients.Significance and impact of study: MIC of the antifungal efficacy relating to EOs was evaluated. The EOs tests showed no cytotoxic effect at very low concentrations, ranging from 0.03% (IC50 0.9132 mg/mL) (L. hybrid Abrialis) to 0.001% (IC50 1.631 mg/mL) (L. hybrid R.C.).

Exploring the Multi-Faceted Potential of Carob (Ceratonia siliqua var. Rahma) Leaves from Morocco: A Comprehensive Analysis of Polyphenols Profile, Antimicrobial Activity, Cytotoxicity against Breast Cancer Cell Lines, and Genotoxicity

The botanical species Ceratonia siliqua L., commonly referred to as the Carob tree, and locally as "L'Kharrûb", holds significance as an agro-sylvo-pastoral species, and is traditionally utilized in Morocco for treating a variety of ailments. This current investigation aims to ascertain the antioxidant, antimicrobial, and cytotoxic properties of the ethanolic extract of C. siliqua leaves (CSEE). Initially, we analyzed the chemical composition of CSEE through high-performance liquid chromatography with Diode-Array Detection (HPLC-DAD). Subsequently, we conducted various assessments, including DPPH scavenging capacity, β-carotene bleaching assay, ABTS scavenging, and total antioxidant capacity assays to evaluate the antioxidant activity of the extract. In this study, we investigated the antimicrobial properties of CSEE against five bacterial strains (two gram-positive, Staphylococcus aureus, and Enterococcus faecalis; and three gram-negative bacteria, Escherichia coli, Escherichia vekanda, and Pseudomonas aeruginosa) and two fungi (Candida albicans, and Geotrichum candidum). Additionally, we evaluated the cytotoxicity of CSEE on three human breast cancer cell lines (MCF-7, MDA-MB-231, and MDA-MB-436) and assessed the potential genotoxicity of the extract using the comet assay. Through HPLC-DAD analysis, we determined that phenolic acids and flavonoids were the primary constituents of the CSEE extract. The results of the DPPH test indicated a potent scavenging capacity of the extract with an IC₅₀ of 302.78 ± 7.55 µg/mL, which was comparable to that of ascorbic acid with an IC₅₀ of 260.24 ± 6.45 µg/mL. Similarly, the β-carotene test demonstrated an IC₅₀ of 352.06 ± 12.16 µg/mL, signifying the extract's potential to inhibit oxidative damage. The ABTS assay revealed IC₅₀ values of 48.13 ± 3.66 TE µmol/mL, indicating a strong ability of CSEE to scavenge ABTS radicals, and the TAC assay demonstrated an IC₅₀ value of 165 ± 7.66 µg AAE/mg. The results suggest that the CSEE extract had potent antioxidant activity. Regarding its antimicrobial activity, the CSEE extract was effective against all five tested bacterial strains, indicating its broad-spectrum antibacterial properties. However, it only showed moderate activity against the two tested fungal strains, suggesting it may not be as effective against fungi. The CSEE exhibited a noteworthy dose-dependent inhibitory activity against all the tested tumor cell lines in vitro. The extract did not induce DNA damage at the concentrations of 6.25, 12.5, 25, and 50 µg/mL, as assessed by the comet assay. However, the 100 µg/mL concentration of CSEE resulted in a significant genotoxic effect compared to the negative control. A computational analysis was conducted to determine the physicochemical and pharmacokinetic characteristics of the constituent molecules present in the extract. The Prediction of Activity Spectra of Substances (PASS) test was employed to forecast the potential biological activities of these molecules. Additionally, the toxicity of the molecules was evaluated using the Protox II webserver.

In Vitro Synergistic Inhibitory Activity of Natural Alkaloid Berberine Combined with Azithromycin against Alginate Production by Pseudomonas aeruginosa PAO1

Background. Berberine (BER) is a natural isoquinoline alkaloid which extensively been applied to treat bacterial infection in TCM for a long time. Alginate is an important component of Pseudomonas aeruginosa biofilm. Herein, we investigated the effects of berberine and azithromycin (AZM) on alginate in the biofilm of P. aeruginosa PAO1. Methods. The MIC and synergistic activity of BER and AZM against PAO1 were determined using the micro broth dilution and checkerboard titration methods, respectively. The effect of BER on PAO1 growth was evaluated using a time-kill assay. Moreover, the effects of BER, AZM, and a combination of both on PAO1 biofilm formation, kinesis, and virulence factor expression were evaluated at subinhibitory concentrations. The alginate content in the biofilm was detected using ELISA, and the relative expression of alginate formation-related genes algD, algR, and algG was detected by qRT-PCR. Results. Simultaneous administration of berberine significantly reduced the MIC of azithromycin, and berberine at a certain concentration inhibited PAO1 growth. Moreover, combined berberine and azithromycin had synergistic effects against PAO1, significantly reducing biofilm formation, swarming, and twitching motility, and the production of virulence factors. The relative expression of alginate-related regulatory genes algG, algD, and algR of the combined treatment group was significantly lower than that of the control group. Conclusion. In summary, berberine and azithromycin in combination had a significant synergistic effect on the inhibition of alginate production by P. aeruginosa. Further molecular studies are in great need to reveal the mechanisms underlying the synergistic activity between berberine and azithromycin.

Assessment of Phage-Mediated Inhibition and Removal of Multidrug-Resistant Pseudomonas aeruginosa Biofilm on Medical Implants

Purpose

Despite the growing interest in bacteriophage (phage) usage for the prevention, control, and removal of bacterial biofilms, few scientific data exist on phage applications on medical implant surfaces, while none exists on multiple implants. In this study, we aimed to isolate, biophysically characterize and assess phages as potential antibiofilm agents to inhibit and remove multidrug-resistant (MDR) Pseudomonas aeruginosa biofilm on catheter and endotracheal tube surfaces.

Methods

The well-identified stored clinical isolates (n = 7) of MDR P. aeruginosa were obtained from Jimma Medical Center. Specific phages were isolated and characterized based on standard protocols. The phages were tested for their antibiofilm effects in preventing colonization and removing preformed biofilms of MDR P. aeruginosa, following phage coating and treatment of catheter and endotracheal tube segments.

Results

Two P. aeruginosa-specific phages (ΦJHS-PA1139 and ΦSMK-PA1139) were isolated from JMC compound sewage sources. The phages were biophysically characterized as being thermally stable up to 40°C and viable between pH 4.0 and 11.0. The two phages tested against clinical MDR strains of P. aeruginosa showed broad host ranges but not on other tested bacterial species. Both phages reduced MDR bacterial biofilms during the screening step. The phage-coated segments showed 1.2 log10 up to 3.2 log10 inhibition relative to non-coated segments following 6 h coating of segments prior to microbial load exposure. In both phages, 6 h treatment of the segments with 106 PFU/mL yielded 1.0 log10 up to 1.6 log10 reductions for ΦJHS and 1.6 log10 up to 2.4 log10 reductions for ΦSMK.

Conclusion

Our results suggest that phages have great potential to serve the dual purpose as surface coating agents for preventing MDR bacterial colonization in medical implants and as biofilm removal agents in implant-associated infections.

Anti-inflammatory effects of lavender and eucalyptus essential oils on the in vitro cell culture model of bladder pain syndrome using T24 cells

BACKGROUND

Interstitial cystitis (IC) has a chronic chemical irritation and inflammation of non-bacterial origin in the bladder wall leading to various severe symptoms. There is evidence that chronic inflammation is significantly associated with abnormal urothelial barrier function, epithelial dysfunction. This is the underlying cause of urothelial apoptosis and sterile inflammation.

METHOD

The anti-inflammatory effects of lavender and eucalyptus essential oils (EOs) and their main components (linalool and eucalyptol) were investigated in the T24 human bladder epithelial cell line on TNFα stimulated inflammation, at 3 types of treatment schedule. The mRNA of pro-inflammatory cytokines (IL-1β, IL-6, IL-8) were measured by Real Time PCR. Human IL-8 ELISA measurement was performed as well at 3 types of treatment schedule. The effects of lavender and eucalyptus EOs and their main components were compared to the response to NFκB inhibitor ACHP (2-amino-6-[2-(cyclopropylmethoxy)-6-hydroxyphenyl]-4-(4-piperidinyl)-3-pyridinecarbonitrile).

RESULT

There is no significant difference statistically, but measurements show that lavender EOs are more effective than eucalyptus EO. Long time treatment (24 h) of both lavender EO and linalool showed higher effect in decreasing pro-inflammatory cytokine mRNA expression than ACHP inhibitor following TNFα pre-treatment. Moreover, both lavender EOs were found to be significantly more effective in decreasing IL-8 secretion of T24 cells after TNFα pre-treatment compared to the ACHP NFκB-inhibitor.

CONCLUSION

The lavender EOs may be suitable for use as an adjunct to intravesical therapy of IC. Their anti-inflammatory effect could well complement glycosaminoglycan-regenerative therapy in the urinary bladder after appropriate pharmaceutical formulation.

Evaluation of Wound Healing and Antibacterial Activities of Solvent Fractions of 80% Methanol Leaf Extract of Brucea antidysenterica J.F. Mill (Simaroubaceae)

Background

Brucea antidysenterica is a well-known medicinal plant that has traditionally been used to treat a variety of ailments, including wound healing. Supporting the traditional claims, wound healing, antibacterial, anti-inflammatory, and antioxidant activities of the crude extracts of different parts of the plant were reported. The aim of this study was to evaluate the wound healing and antibacterial activities of solvent fractions of the menthol leaf extract of Brucea antidysenterica.

Methods

Methanol (80%) leaf extract of Brucea antidysenterica was fractionated using three solvents; water, n-butanol and chloroform. An ointment containing 2% and 4% of each fraction was formulated and applied to wounds inflicted on rats topically. The wound contraction rate, period of epithelialization, and breaking strength were analysed. In vitro antibacterial activities were tested using the agar diffusion method. The macro-tube dilution technique was used to determine the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC) was determined by sub-culturing the MIC and concentrations below the MIC.

Results

The 2% and 4% aqueous fractions (AF) significantly increased wound contraction (p 0.001) compared to the negative control and increased tensile strength compared to untreated (p 0.001). Among the three fractions, the n-butanol fraction showed the highest antibacterial growth inhibition, ranging from 8 mm (E. coli) to 16 mm (S. aureus).

Conclusion

Data obtained from this study collectively indicated that the aqueous fraction of 80% methanol leaf extract of B. antidysenterica possesses wound healing and antibacterial activities.

New β-Lactam Antibiotics and Ceragenins - A Study to Assess Their Potential in Treatment of Infections Caused by Multidrug-Resistant Strains of Pseudomonas aeruginosa

Background

The increasing number of infections caused by antibiotic resistant strains of Pseudomonas aeruginosa posed a very serious challenge for clinical practice. This standing is driving scientists to develop new antibiotics against these microorganisms.

Methods

In this study, we measured the MIC/MBC values and estimated the ability of tested molecules to prevent bacterial biofilm formation to explore the effectiveness of β-lactam antibiotics ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, and ceragenins CSA-13, CSA-44, and CSA-131 against 150 clinical isolates of Pseudomonas aeruginosa that were divided into five groups, based on their antibiotic resistance profiles to beta-lactams. Selected strains of microorganisms from each group were also subjected to prolonged incubations (20 passages) with ceragenins to probe the development of resistance towards those molecules. Cytotoxicity of tested ceragenins was evaluated using human red blood cell (RBCs) hemolysis and microscopy observations of human lung epithelial A549 cells after ceragenin treatment. Poloxamer 407 (pluronic F-127) at concentrations ranging from 0.5% to 5% was tested as a potential drug delivery substrate to reduce ceragenin toxicity.

Results

Collected data proved that ceragenins at low concentrations are highly active against clinical strains of Pseudomonas aeruginosa regardless of their resistance mechanisms to conventional antibiotics. Ceragenins also show low potential for resistance development, high antibiofilm activity, and controlled toxicity when used together with poloxamer 407.

Conclusion

This data strongly supports the need for further study directed to develop this group of molecules as new antibiotics to fighting infections caused by antibiotic resistant strains of Pseudomonas aeruginosa.

Model-Informed Precision Dosing of Antibiotics in Osteoarticular Infections

As a heterogeneous and wide inflammation, osteoarticular infection (OAI) shows an increasing incidence in recent years. Staphylococcus aureus is the most important pathogen causing OAI. The antibiotic treatment will affect the outcomes of OAI patients, and the drug selection and dosage regimen highly rely on patients’ variability, pathogen susceptibility, and drug property like bone permeability. Model-informed precision dosing (MIPD) provides options to describe and quantify the pharmacokinetic (PK) variability of the OAI population using different models, such as the population pharmacokinetic (PPK) model and physiological-based pharmacokinetic (PB/PK) model. In the present review, we highlighted that the MIPD of antibiotics played a critical role in OAI and listed the dose regimen recommended by the model. Collectively, our current study provided a valuable reference for the treatment of patients and improved the safety and efficiency of drug use.

No Correlation between Biofilm Formation, Virulence Factors, and Antibiotic Resistance in Pseudomonas aeruginosa: Results from a Laboratory-Based In Vitro Study

Pseudomonas aeruginosa (P. aeruginosa) possesses a plethora of virulence determinants, including the production of biofilm, pigments, exotoxins, proteases, flagella, and secretion systems. The aim of our present study was to establish the relationship between biofilm-forming capacity, the expression of some important virulence factors, and the multidrug-resistant (MDR) phenotype in P. aeruginosa. A total of three hundred and two (n = 302) isolates were included in this study. Antimicrobial susceptibility testing and phenotypic detection of resistance determinants were carried out; based on these results, isolates were grouped into distinct resistotypes and multiple antibiotic resistance (MAR) indices were calculated. The capacity of isolates to produce biofilm was assessed using a crystal violet microtiter-plate based method. Motility (swimming, swarming, and twitching) and pigment-production (pyoverdine and pyocyanin) were also measured. Pearson correlation coefficients (r) were calculated to determine for antimicrobial resistance, biofilm-formation, and expression of other virulence factors. Resistance rates were the highest for ceftazidime (56.95%; n = 172), levofloxacin (54.97%; n = 166), and ciprofloxacin (54.64%; n = 159), while lowest for colistin (1.66%; n = 5); 44.04% (n = 133) of isolates were classified as MDR. 19.87% (n = 60), 20.86% (n = 63) and 59.27% (n = 179) were classified as weak, moderate, and strong biofilm producers, respectively. With the exception of pyocyanin production (0.371 ± 0.193 vs. non-MDR: 0.319 ± 0.191; p = 0.018), MDR and non-MDR isolates did not show significant differences in expression of virulence factors. Additionally, no relevant correlations were seen between the rate of biofilm formation, pigment production, or motility. Data on interplay between the presence and mechanisms of drug resistance with those of biofilm formation and virulence is crucial to address chronic bacterial infections and to provide strategies for their management.

Chemical Composition and Assessment of Antimicrobial Activity of Lavender Essential Oil and Some By-Products

The producers of essential oils from the Republic of Moldova care about the quality of their products and at the same time, try to capitalize on the waste from processing. The purpose of the present study was to analyze the chemical composition of lavender (Lavanda angustifolia L.) essential oil and some by-products derived from its production (residual water, residual herbs), as well as to assess their “in vitro” antimicrobial activity. The gas chromatography-mass spectrometry analysis of essential oils produced by seven industrial manufacturers led to the identification of 41 constituents that meant 96.80–99.79% of the total. The main constituents are monoterpenes (84.08–92.55%), followed by sesquiterpenes (3.30–13.45%), and some aliphatic compounds (1.42–3.90%). The high-performance liquid chromatography analysis allowed the quantification of known triterpenes, ursolic, and oleanolic acids, in freshly dried lavender plants and in the residual by-products after hydrodistillation of the essential oil. The lavender essential oil showed good antibacterial activity against Bacillus subtilis, Pseudomonas fluorescens, Xanthomonas campestris, Erwinia carotovora at 300 μg/mL concentration, and Erwinia amylovora, Candida utilis at 150 μg/mL concentration, respectively. Lavender plant material but also the residual water and ethanolic extracts from the solid waste residue showed high antimicrobial activity against Aspergillus niger, Alternaria alternata, Penicillium chrysogenum, Bacillus sp., and Pseudomonas aeroginosa strains, at 0.75–6.0 μg/mL, 0.08–0.125 μg/mL, and 0.05–4.0 μg/mL, respectively.

Mid-term follow-up results after implementing a new strategy for the diagnosis and management of periprosthetic joint infections

BACKGROUND

Periprosthetic joint infections (PJIs) represent one of the most serious complications associated with joint replacement surgeries, a complication also of modern orthopedic surgery despite the efforts that occurred in this field. Frequently PJIs lead to prolonged morbidity, increased costs and mortality.

METHODS

We are conducting a single-center observational cohort ongoing study in the Academic Emergency Hospital Sibiu, Romania, study in which sonication of the retrieved and as a rapid method of bacteria detection, molecular identification of bacteria by 16S rRNA beacon-based fluorescent in situ hybridization (bbFISH) are used.

RESULTS

A total of 61 patients were enrolled in this study. The diagnosis of aseptic loosening was established in 30 cases (49.1%) and the diagnosis of periprosthetic joint infection was established at 31 patients (50.8%). The mean follow-up period in the subgroup of patients diagnosed with periprosthetic joint infections was 36.06 ± 12.59 months (range: 1-54). The 25-months Kaplan-Meier survival rate as the end point, as a consequence of the period of enrollment and a different follow-up period for each type of surgical procedure, was 75% after debridement and implant retention, 91.7% after one-stage exchange, 92.3% after two-stage exchange, and 100% after three-stage exchange. There were no significant differences in survival percentage.

CONCLUSIONS

Our study has good results similar to previously published data. We cannot recommend one strategy of managing prosthetic joint infections over the other. Definitely, there is a need for prospective randomized controlled trials.

The diversity of unique 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid coding common genes and Universal stress protein in Ectoine TRAP cluster (UspA) in 32 Halomonas species

OBJECTIVES

To decipher the diversity of unique ectoine-coding housekeeping genes in the genus Halomonas.

RESULTS

In Halomonas, 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid has a crucial role as a stress-tolerant chaperone, a compatible solute, a cell membrane stabilizer, and a reduction in cell damage under stressful conditions. Apart from the current 16S rRNA biomarker, it serves as a blueprint for identifying Halomonas species. Halomonas elongata 1H9 was found to have 11 ectoine-coding genes. The presence of a superfamily of conserved ectoine-coding among members of the genus Halomonas was discovered after genome annotations of 93 Halomonas spp. As a result of the inclusion of 11 single copy ectoine coding genes in 32 Halomonas spp., genome-wide evaluations of ectoine coding genes indicate that 32 Halomonas spp. have a very strong association with H. elongata 1H9, which has been proven evidence-based approach to elucidate phylogenetic relatedness of ectoine-coding child taxa in the genus Halomonas. Total 32 Halomonas species have a single copy number of 11 distinct ectoine-coding genes that help Halomonas spp., produce ectoine under stressful conditions. Furthermore, the existence of the Universal stress protein (UspA) gene suggests that Halomonas species developed directly from primitive bacteria, highlighting its role during the progression of microbial evolution.

A systematic review on ethnopharmacology, phytochemistry and pharmacological aspects of Thymus vulgaris Linn

Thymus vulgaris Linn. is a medicinal and culinary herb from the Southern European region known for its anti-infective, cardioprotective, gastroprotective, anti-inflammatory, and immunomodulatory activities since the Egyptian era. The reported pharmacological activities of T. vulgaris L. include antibacterial, antioxidant, anti-inflammatory, antiviral, and anti-cancerous activities. In this review, a comprehensive approach is put forth to scrutinize and report the available data on phytochemistry, ethnopharmacology, pharmacology, and toxicology of the plant. The different extracts and essential oil obtained from the plant have been assessed and reported to treat ailments like microbial infections, inflammation, non-communicable diseases like cancer, and sexually transmitted diseases like HIV-1 and Herpes. The literature review has also indicated the use of volatile oils, phenolic acids, terpenoids, flavonoids, saponins, steroids, tannins, alkaloids, and polysaccharides in pharmacotherapy. Applications of these compounds including antidiabetic, anti-Alzheimer's, cardio, neuro and hepatoprotective, anti-osteoporosis, sedative, immunomodulatory, antioxidant, anti-tyrosinase, antispasmodic, antinociceptive, gastroprotective, anticonvulsant, antihypertensive, antidepressant, anti-amnesia, and anti-helminthic activities have been mentioned. Further, based on research gaps, recommendations have been provided to evaluate T. vulgaris L. systematically to develop plant-based drugs, nutraceuticals, and to evaluate their clinical efficiency and safety.

In vitro Effect of the Combination of Aztreonam and Amoxicillin/Clavulanic Acid Against Carbapenem-Resistant Gram-Negative Organisms Producing Metallo-β-Lactamase

Introduction

Antibiotics for treating infectious diseases caused by carbapenem-resistant Gram-negative pathogens (CR-GNOs) are very limited in clinical practice. We aim to provide supportive evidence by revealing the combined effect of aztreonam (ATM) and amoxicillin/clavulanic acid (AMC) against GNOs with carbapenem resistance mediated by metallo-β-lactamase (MBL).

Methods

All isolates were identified by the VITEK system and EDTA inhibitory assays. PCR followed by sequencing was conducted to confirm the genotypes of MBL and extended spectrum β-lactamase (ESBL). Time kill assay was performed to clarify the bactericidal effect of drug combination.

Results

A total of 59 MBL-producing CR-GNOs (33 Enterobacteriaceae spp. isolates and 26 Pseudomonadales isolates) were identified and there found three MBL genes, namely, bla_IMP, bla_NDM and bla_VIM, with ratios of 76.2%, 11.8% and 11.8%, respectively. The Enterobacteriaceae spp. isolates were commonly positive for the ESBL genes, including bla_TEM (18 isolates), bla_SHV (20 isolates) and bla_CTX-M-1 (8 isolates), while the P. aeruginosa isolates were positive for bla_OXA-10 (11 isolates). The checkerboard microdilution assay was used to detect combination effect of ATM and AMC, which showed synergy (97.0%) and partial synergy (3.0%) in Enterobacteriaceae spp. isolates, and partial synergy (42.3%) and indifference (34.6%) in the Pseudomonadales isolates. Four Enterobacteriaceae spp. isolates were selected for a time-kill assay, and rapid bactericidal effects were observed in the combination groups compared to the control and mono-ATM groups; these effects began in the first hour and continued to the sixth hour, yielding a 5- to 7-fold reduction in Log10 CFU/mL.

Discussion

The combination of ATM and AMC would be an available option to control infections caused by MBL-producing CR-GNOs, especially Enterobacteriaceae spp. isolates that coproduce ESBLs, and exhibit significant synergic effects in vitro.

Time-dependent efficacy of combination of silver-containing hydroxyapatite coating and vancomycin on methicillin-resistant Staphylococcus aureus biofilm formation in vitro

OBJECTIVE

We developed a silver-containing hydroxyapatite (Ag-HA) coating to prevent periprosthetic joint infection (PJI). Methicillin-resistant Staphylococcus aureus (MRSA) is the main PJI-causing bacteria. Previously, we had reported the combined effect of Ag-HA coating and vancomycin (VCM) on MRSA biofilm formation 24 h after MRSA inoculation. In this study, we investigated the time-dependent efficacy of Ag-HA coating and VCM on MRSA biofilm formation on Ti discs in vitro by three-dimensional confocal laser scanning microscopic analysis.

RESULTS

For the Ti VCM and HA VCM groups, the total biofilm volumes per area at 96 h after MRSA inoculation were significantly larger than those at 48 h after MRSA inoculation, respectively (p < 0.001). In contrast, for the Ag-HA VCM group, the total biofilm volume per area at 96 h was significantly smaller than that at 48 h (p < 0.0001). Moreover, 96 h after MRSA inoculation, the total biofilm volume per area of the Ag-HA VCM groups was significantly smaller than those of the Ti VCM and HA VCM groups (p < 0.0001). Thus, the combination of Ag-HA and VCM might be useful for the prevention of MRSA-associated PJI.

It's Not Easy Being Green: A Narrative Review on the Microbiology, Virulence and Therapeutic Prospects of Multidrug-Resistant Pseudomonas aeruginosa

Pseudomonas aeruginosa is the most frequent cause of infection among non-fermenting Gram-negative bacteria, predominantly affecting immunocompromised patients, but its pathogenic role should not be disregarded in immunocompetent patients. These pathogens present a concerning therapeutic challenge to clinicians, both in community and in hospital settings, due to their increasing prevalence of resistance, and this may lead to prolonged therapy, sequelae, and excess mortality in the affected patient population. The resistance mechanisms of P. aeruginosa may be classified into intrinsic and acquired resistance mechanisms. These mechanisms lead to occurrence of resistant strains against important antibiotics-relevant in the treatment of P. aeruginosa infections-such as β-lactams, quinolones, aminoglycosides, and colistin. The occurrence of a specific resistotype of P. aeruginosa, namely the emergence of carbapenem-resistant but cephalosporin-susceptible (Car-R/Ceph-S) strains, has received substantial attention from clinical microbiologists and infection control specialists; nevertheless, the available literature on this topic is still scarce. The aim of this present review paper is to provide a concise summary on the adaptability, virulence, and antibiotic resistance of P. aeruginosa to a readership of basic scientists and clinicians.

Novel Antibiotic Combinations of Diverse Subclasses for Effective Suppression of Extensively Drug-Resistant Methicillin-Resistant Staphylococcus aureus (MRSA)

The emergence of multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), the chief etiological agent for a range of refractory infections, has rendered all β-lactams ineffective against it. The treatment process is further complicated with the development of resistance to glycopeptides, primary antibiotics for treatment of MRSA. Antibiotic combination therapy with existing antimicrobial agents may provide an immediate treatment option. Minimum inhibitory concentrations (MICs) of 18 different commercially available antibiotics were determined along with their 90 possible pairwise combinations and 64 triple combinations to filter out 5 best combinations. Time-Kill kinetics of these combinations were then analyzed to find collateral bactericidal combinations which were then tested on other randomly selected MRSA isolates. Among the top 5 combinations including levofloxacin-ceftazidime; amoxicillin/clavulanic acid-tobramycin; amoxicillin/clavulanic acid-cephradine; amoxicillin/clavulanic acid-ofloxacin; and piperacillin/tazobactam-tobramycin, three combinations were found to be collaterally effective. Levofloxacin-ceftazidime acted synergistically in 80% of the tested clinical MRSA isolates. First-line β-lactams of lower generations can be used effectively against MRSA infection when used in combination. Antibiotics other than glycopeptides may still work in combination.

Assessment of Public Awareness, Attitude, and Practice Regarding Antibiotic Resistance in Kemissie Town, Northeast Ethiopia: Community-Based Cross-Sectional Study

BACKGROUND

Antibiotic resistance is increasing to dangerously high levels globally with subsequent higher medical costs, prolonged hospital stays and increased levels of mortality. Ensuring patients' knowledge, attitude, and proper use of antimicrobials is one of the strategies to control resistance. The aim of this study is to evaluate the public awareness, attitude, and practice regarding antimicrobial use and resistance in Kemissie Town, Northeast Ethiopia.

METHODS

A community-based, cross-sectional study was conducted on 385 adults selected using systematic random sampling in Kemissie town from March 1 to May 1, 2019. A home-to-home visit interview was done using a structured interview guide. The data were coded individually and entered into a computer using Epi-info version 3.5.1 and then exported to SPSS version 23.0 for analysis. Univariate analyses were used to describe the categorical variables.

RESULTS

Of the 345 respondents who took antibiotics, three quarters (74.78%) received antibiotics with a prescription. Of the total respondents, 17.7% of the participants believed unnecessary use of antibiotics enhances resistance to bacteria. Of those who took antibiotics, the majority (72.5 %) finished the full course of treatment. Out of the total 374 respondents, 41.6% had awareness on the fact that antibiotics resistance can affect the development of resistance in the whole community. More than half (51.9%) of the respondents believed that the rational use of antibiotics can reduce the risk of antimicrobial resistance.

CONCLUSION

The majority of the respondents were still unaware of antibiotic resistance and its implications. This requires close attention from policy-makers and healthcare professionals. The community of Kemissie town had a positive attitude towards finishing antibiotic regimens. This study also identified crucial gaps in the practices of the community about the use of antibiotics.

Investigating the Effect of Nano-Curcumin on the Expression of Biofilm Regulatory Genes of Pseudomonas aeruginosa

BACKGROUND

Pseudomonas aeruginosa is an opportunistic pathogen that causes serious nosocomial infections, especially in immunodeficient patients and cystic fibrosis, cancer, and burned individuals. The biofilm that plays an important role in the virulence of P. aeruginosa is under the regulation of quorum sensing and two-component regulatory systems of bacteria. Curcumin, an active phenolic extract of turmeric has shown an inhibitory effect on the biofilm formation of some pathogenic bacteria. Thus, the present study aims to evaluate the effect of Nano-Curcumin on the expression of major regulatory genes involved in biofilm formation of P. aeruginosa.

MATERIALS AND METHODS

The biofilm formation of P. aeruginosa ATCC 10145 was assessed in the presence of 15, 20, and 25 µg/mL concentrations of Nano-Curcumin using the microplate titer method. The effect of Nano-Curcumin on the expression level of regulatory genes were determined by relative reverse transcriptase-realtime PCR.

RESULTS

In the absence of Nano-Curcumin, P. aeruginosa strain ATCC 10145 strongly produced biofilm (3+) and in the presence of 15 and 20 µg/mL, biofilm formation was reduced to moderate (2+) and weak biofilm producer (1+), respectively. Nano-Curcumin at a concentration of 25µg/mL inhibited biofilm formation in P. aeruginosa. The expression of regulatory genes was not affected by biofilm inhibitory concentrations of Nano-Curcumin.

CONCLUSION

The antibiofilm mechanism of Curcumin is not related to the downregulation of regulatory systems of P. aeruginosa and probably it prevents the formation of a complete biofilm structure.

Phytochemical Compositions and Biological Activities of Essential Oils from the Leaves, Rhizomes and Whole Plant of Hornstedtia bella Škorničk

The rapid emergence of drug-resistant strains and novel viruses have motivated the search for new anti-infectious agents. In this study, the chemical compositions and cytotoxicity, as well as the antibacterial, antifungal, antitrichomonas, and antiviral activities of essential oils from the leaves, rhizomes, and whole plant of Hornstedtia bella were investigated. The GC/MS analysis showed that β-pinene, E-β-caryophyllene, and α-humulene were found at high concentrations in the essential oils. The essential oils exhibited (i) inhibition against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis with minimum inhibitory concentrations (MIC) and minimum lethal concentration (MLC) values from 1 to 4% (v/v); (ii) MIC and MLC values from 2 to 16% (v/v) in Candida tropicalis and Candida parapsilosis; (iii) MIC and MLC values from 4 to 16% in Enterococcus faecalis; and (iv) MIC and MLC values from 8 to greater than or equal to 16% (v/v) in the remaining strains, including Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Candida albicans, and Candida glabrata. In antitrichomonas activity, the leaves and whole-plant oils of Hornstedtia bella possessed IC₅₀, IC₉₀, and MLC values of 0.008%, 0.016%, and 0.03% (v/v), respectively, whilst those of rhizomes oil had in turn, 0.004%, 0.008%, and 0.016% (v/v).Besides, the leaf oil showed a weak cytotoxicity against Vero 76 and MRC-5; meanwhile, rhizomes and whole-plant oils did not exert any toxic effects on cell monolayers. Finally, these oils were not active against EV-A71.

In vitro Antimicrobial Activity of Essential Oil Extracted from Leaves of Leoheo domatiophorus Chaowasku, D.T. Ngo and H.T. Le in Vietnam

:The present study aimed to determine the antimicrobial activity and chemical composition of leaves-extracted essential oil of Leoheo domatiophorus Chaowasku, D.T. Ngo and H.T. Le (L. domatiophorus), including antibacterial, antimycotic, antitrichomonas and antiviral effects. The essential oil was obtained using hydrodistillation, with an average yield of 0.34 ± 0.01% (v/w, dry leaves). There were 52 constituents as identified by GC/MS with available authentic standards, representing 96.74% of the entire leaves oil. The essential oil was comprised of three main components, namely viridiflorene (16.47%), (-)-δ-cadinene(15.58%) and γ-muurolene (8.00%). The oil showed good antimicrobial activities against several species: Gram-positive strains: Staphylococcus aureus (two strains) and Enterococcus faecalis, with Minimum Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC) values from 0.25 to 1% (v/v); Gram-negative strains such as Escherichia coli (two strains), Pseudomonas aeruginosa (two strains) and Klebsiella pneumoniae, with MIC and MLC values between 2% and 8% (v/v); and finally Candida species, having MIC and MLC between 0.12 and 4% (v/v).Antitrichomonas activity of the oil was also undertaken, showing IC₅₀, IC₉₀ and MLC values of 0.008%, 0.016% and 0.03% (v/v), respectively, after 48h of incubation. The essential oil resultedin being completely ineffective against tested viruses, ssRNA+ (HIV-1, YFV, BVDV, Sb-1, CV-B4), ssRNA- (hRSVA2, VSV), dsRNA (Reo-1), and dsDNA (HSV-1, VV) viruses with EC₅₀ values over 100 µg/mL. This is the first, yet comprehensive, scientific report about the chemical composition and pharmacological properties of the essential oil in L. domatiophorus.