Drug resistance profile and molecular characterization of extended spectrum beta-lactamase (ESβL)-producing Pseudomonas aeruginosa isolated from burn wound infections. Essential oils and their potential for utilization

Synergistic Antibacterial and Antibiofilm Effects of Clindamycin and Zinc Oxide Nanoparticles Against Pathogenic Oral Bacillus Species

Oral bacterial pathogens, including Bacillus species, form biofilms that enhance antibiotic resistance, promote bacterial adherence, and maintain structural integrity. The ability of bacteria to form biofilms is directly linked to several oral diseases, including gingivitis, dental caries, periodontitis, periapical periodontitis, and peri-implantitis. These biofilms act as a predisposing factor for such infections. Nanoparticles, known for their strong antibacterial properties, can target specific biofilm-forming microorganisms without disturbing the normal microflora of the oral cavity. This study focuses on the biofilm-forming ability and clindamycin (CM) resistance of Bacillus species found in the oral cavity. It aims to evaluate the antibacterial and antibiofilm properties of zinc oxide nanoparticles (ZnO-NPs) against oral Bacillus species and assess the effectiveness of combining CM with ZnO-NPs in reducing antibiotic resistance. The antibacterial susceptibility of Bacillus isolates was tested using ZnO-NPs and CM, demonstrating synergistic effects that reduced the minimum inhibitory concentrations by up to 8-fold. The fractional inhibitory concentration (FIC) index indicated a significant synergistic effect in most strains, with FIC values ranging from 0.375 to 0.5. It was found that the majority of Bacillus strains exhibited significant biofilm-forming capabilities, which were reduced when treated with the ZnO-NPs and CM combination. The study also evaluated the cytotoxicity of ZnO-NPs on cancer cells (CAL27) and normal fibroblasts (HFB4). CAL27 cells showed stronger cytotoxicity, with an IC50 of 52.15 µg/mL, compared to HFB4 cells, which had an IC50 of 36.3 µg/mL. Genetic analysis revealed the presence of biofilm-associated genes such as sipW and tasA, along with antibiotic resistance genes (ermC), which correlated with the observed biofilm phenotypes. Overall, this study demonstrates the potential of combining ZnO-NPs with CM to overcome antibiotic resistance and biofilm formation in the oral bacterial pathogens, Bacillus species. These findings suggest new approaches for developing more effective dental treatments targeting oral biofilm-associated infections and antibiotic resistance.

Microplastics as an Emerging Potential Threat: Toxicity, Life Cycle Assessment, and Management

The pervasiveness of microplastics (MPs) in terrestrial and aquatic ecosystems has become a significant environmental concern in recent years. Because of their slow rate of disposal, MPs are ubiquitous in the environment. As a consequence of indiscriminate use, landfill deposits, and inadequate recycling methods, MP production and environmental accumulation are expanding at an alarming rate, resulting in a range of economic, social, and environmental repercussions. Aquatic organisms, including fish and various crustaceans, consume MPs, which are ultimately consumed by humans at the tertiary level of the food chain. Blocking the digestive tracts, disrupting digestive behavior, and ultimately reducing the reproductive growth of entire living organisms are all consequences of this phenomenon. In order to assess the potential environmental impacts and the resources required for the life of a plastic product, the importance of life cycle assessment (LCA) and circularity is underscored. MPs-related ecosystem degradation has not yet been adequately incorporated into LCA, a tool for evaluating the environmental performance of product and technology life cycles. It is a technique that is designed to quantify the environmental effects of a product from its inception to its demise, and it is frequently employed in the context of plastics. The control of MPs is necessary due to the growing concern that MPs pose as a newly emergent potential threat. This is due to the consequences of their use. This paper provides a critical analysis of the formation, distribution, and methods used for detecting MPs. The effects of MPs on ecosystems and human health are also discussed, which posed a great challenge to conduct an LCA related to MPs. The socio-economic impacts of MPs and their management are also discussed. This paper paves the way for understanding the ecotoxicological impacts of the emerging MP threat and their associated issues to LCA and limits the environmental impact of plastic.

Phenotypic and genomic characterization of Pseudomonas aeruginosa isolates recovered from catheter-associated urinary tract infections in an Egyptian hospital

Catheter-associated urinary tract infections (CAUTIs) represent one of the major healthcare-associated infections, and Pseudomonas aeruginosa is a common Gram-negative bacterium associated with catheter infections in Egyptian clinical settings. The present study describes the phenotypic and genotypic characteristics of 31 P. aeruginosa isolates recovered from CAUTIs in an Egyptian hospital over a 3 month period. Genomes of isolates were of good quality and were confirmed to be P. aeruginosa by comparison to the type strain (average nucleotide identity, phylogenetic analysis). Clonal diversity among the isolates was determined; eight different sequence types were found (STs 244, 357, 381, 621, 773, 1430, 1667 and 3765), of which ST357 and ST773 are considered to be high-risk clones. Antimicrobial resistance (AMR) testing according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines showed that the isolates were highly resistant to quinolones [ciprofloxacin (12/31, 38.7 %) and levofloxacin (9/31, 29 %) followed by tobramycin (10/31, 32.5 %)] and cephalosporins (7/31, 22.5 %). Genotypic analysis of resistance determinants predicted all isolates to encode a range of AMR genes, including those conferring resistance to aminoglycosides, β-lactamases, fluoroquinolones, fosfomycin, sulfonamides, tetracyclines and chloramphenicol. One isolate was found to carry a 422 938 bp pBT2436-like megaplasmid encoding OXA-520, the first report from Egypt of this emerging family of clinically important mobile genetic elements. All isolates were able to form biofilms and were predicted to encode virulence genes associated with adherence, antimicrobial activity, anti-phagocytosis, phospholipase enzymes, iron uptake, proteases, secretion systems and toxins. The present study shows how phenotypic analysis alongside genomic analysis may help us understand the AMR and virulence profiles of P. aeruginosa contributing to CAUTIs in Egypt.

New Pseudomonas Bacterial Strains: Biological Activity and Characteristic Properties of Metabolites

This paper investigates the antagonistic and plant growth promotion activity of the new indigenous bacteria antagonist strains P. chlororaphis BZR 245-F and Pseudomonas sp. BZR 523-2. It was found that on the 10th day of cultivation, BZR 245-F and BZR 523-2 exhibit an antagonistic activity against F. graminearum at the level of 59.6% and 15.1% and against F. oxysporum var. orthoceras at the level of 50.2% and 8.9%, respectively. Furthermore, the BZR 523-2 strain stimulated the growth of winter wheat seedlings more actively than the BZR 245-F strain. When processing seeds of winter wheat, Pseudomonas sp. BZR 523-2 indicators were higher than in the control: plant height increased by 10.3%, and root length increased by 18.6%. The complex characteristic properties of the metabolite were studied by bioautography and HPLC-MS. Bioautography proved the antifungal activity of phenazine nature compounds synthesized by the new bacterial strains. We qualitatively and quantitatively analyzed them by HPLC-MS analysis of the strain sample metabolites. In the BZR 245-F sample, we found more phenazine compounds of various types. Their total phenazine concentration in the BZR 245-F was more than five times greater than in the BZR 523-2. We defined crucial differences in the quantitative content of the other metabolites. Despite the difference between new indigenous bacteria antagonist strains, they can be used as producers of effective biopesticides for sustainable agriculture management.

Exploring the potential of Rhizopus oryzae AUMC14899 as a novel endophytic fungus for the production of L-tyrosine and its biomedical applications

BACKGROUND

A significant threat to the public's health is the rise in antimicrobial resistance among numerous nosocomial bacterial infections. This may be a detriment to present initiatives to enhance the health of immune-compromised patients. Consequently, attention has been devoted to exploring new bioactive compounds in the field of drug discovery from endophytes. Therefore, this study is the first on the production of L-tyrosine (LT) as a promising bio-therapeutic agent from endophytic fungi.

RESULTS

A new endophytic fungal isolate has been identified for the first time as Rhizopus oryzae AUMC14899 from Opuntia ficus-indica (L.) and submitted to GenBank under the accession number MZ025968. Separation of amino acids in the crude extract of this fungal isolate was carried out, giving a higher content of LT, which is then characterized and purified. LT exhibited strong antibacterial and anti-biofilm activities against multidrug-resistant Gram-negative and Gram-positive bacteria. The recorded minimum inhibitory concentration (MIC) values ranged from 6 to 20 µg/ml. In addition, LT caused a strong reduction in biofilm formation and disrupted the preformed biofilm. Moreover, results indicated that LT supported cell viability, evidencing hemocompatibility and no cytotoxicity.

CONCLUSION

Our findings suggest that LT has potential as a therapeutic agent due to its potential antibacterial, anti-biofilm, hemocompatibility, and lack of cytotoxic activities, which may also increase the range of therapy options for skin burn infections, leading to the development of a novel fungal-based drug.

Protective manifestation of herbonanoceuticals as antifungals: A possible drug candidate for dermatophytic infection

Background and Aims

Fungal dermatophytosis or Tinea is a predominance in about 20%-25% of all total world populations. Dermatophyte infections are mainly caused by fungi belonging to Trichophyton, Epidermophyton, and Microsporum genera along with some other fungi. This epidemiological distribution may change with migration, lifestyle, immunosuppressive state, drug therapy, and socioeconomic conditions.

Methods

The present review indicated the bioefficacy of herbal and herbonanoconjugate as safe management of fungal dermatophytic infection.

Results

It also emphasized the action mechanism as fungicidal and fungistatic with different harmful impacts indicating the need for alternative therapeutics. Simultaneously, the herbal and herbonanoconjugate approaches proved better to manage the prevalence of hepatotoxicity, nephrotoxicity, nausea, altered taste, anemia, GI upsets, hair loss, and so forth. due to conventional oral treatment approaches.

Conclusion

Adoption of the remedial approach can be recommended after preclinical trials' approval as a safe treatment.

Chemical Composition and Antimicrobial Activity of Essential Oils from Three Mediterranean Plants against Eighteen Pathogenic Bacteria and Fungi

The chemical composition and antimicrobial activity of essential oils (EOs) obtained from three medicinal plants of the Moroccan flora were evaluated. The chemical composition of EOs of Thymus leptobotrys, Laurus nobilis and Syzygium aromaticum was determined using a gas chromatograph coupled with mass spectrometry. Carvacrol (75.05%) was the main constituent of T. leptobotrys EOs, while 1,8-cineole (31.48%) and eugenol (82.16%) were the predominant components of L. nobilis and S. aromaticum EOs, respectively. The antimicrobial activity of the EOs was evaluated qualitatively and quantitatively against 18 microbial strains pathogenic to humans by using the disc diffusion method, and by measuring the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC). The EOs of T. leptobotrys were the most active against the strains tested, with inhibitory zone values ranging from 7.00 to 45.00 mm, and MIC and MMC values ranging from 0.312 to 80.00 mg/mL. In many cases, these EOs exhibited higher antibacterial and antifungal activities than the chemical compounds ciprofloxacin and fluconazole, respectively. This high antimicrobial activity can be ascribed to their richness in carvacrol. The EOs of T. leptobotrys, L. nobilis, and S. aromaticum could be considered a promising alternative to replace chemical antimicrobials, and a readily available natural source of bioactive compounds.

Association between biofilm formation gene bla exoU and metallo and extend spectrum beta-lactamase production of multidrug resistance Pseudomonas aeruginosa in clinical samples

BACKGROUND

The presence of biofilm formation exoU gene is significant challenge to infection control management in hospitals and exposure by Pseudomonas aeruginosa may lead to further spread and development of antimicrobial resistance.

METHODS

Out of 227 samples 40 clinical isolates of P. aeruginosa were collected from patients attending public hospitals ( Rizgary, Teaching hospital, Laboratory center, Raparin, Nanakaly hospitals)in Erbil city/Iraq over a period during 2018 to march 2019 and fully characterized by standard bacteriological procedures and antimicrobial susceptibility test and ESBL has been carried out by Vitek 2 compact system and. by Vitek 2 compact system. The identification has been verified by all isolates as P. aeruginosa by using 16S rDNA with product size (956pb).

RESULTS

A high rate of resistance was seen against Penicillin and lincomycin and Piperacillin and chloramphenicol and rifampicin (100 %), whereas Imipenem (5%) were found to be the most effective antimicrobial drugs. Of all P. aeruginosa isolates, 30 (75% %) were identified as MDR, approximately 9(22.5%) of isolates were resistant to 9 drugs in burn samples. Quantitative biofilm determination using the Congo red method revealed that 28 isolates (70%) produced biofilm, biofilm production was significantly higher among MDR P. aeruginosa isolates while coproduction of Extended Spectrum β-lactamase (ESBL) together with Metallo β-lactamase (MBL) ESBLs MBLs recorded in (52.5%) of the isolates. Altogether 40 isolates were processed for analysis by PCR assays and showed that 26(70%) of P. aeruginosa isolates harboured the exoU encoding gene with product size (204) pb was more commonly seen in isolates obtained from burn isolates. In addition, exo U gene was significantly associated with the higher MDR (80%), 8 isolates (76.9%)had exoU gene with ESBL and( 65%) had MBL and the same for MDR (80.8%) in samples for burning.

CONCLUSION

Our results showed surveillance of P. aeruginosa resistance against antimicrobial and ESBL and MBL is fundamental to monitor trends in susceptibility patterns and appropriately guide clinicians in choosing empirical or directed therapy.

Experimental and computational studies of an antiplasmodial derivative of allantoin; antimycobacterial essential oil from Cordia batesii WERNHAM (Boraginaceae)

Background

Chemical and pharmacological investigations were performed on the stems of Cordia batesii (Boraginaeae); chemical studies included quantum calculations applied on a newly described compound.

Results

A new derivative of allantoin (1) named batesiin (2) was characterized. Thirteen other known compounds involving allantoin (1) were either isolated or identified. GC–MS enabled the identification of six compounds from a fraction containing essential oil. MeOH extract and some isolated compounds were tested in vitro against Pf7G8 CQS and Pf Dd2 CQR strains of Plasmodium falciparum; extract disclosed a moderate antiplasmodial activity (IC₅₀ = 50 μg mL⁻¹). Meantime, the CH₂Cl₂ extract and essential oil fraction were tested on a resistant mycobacterial strain of Mycobacterium tuberculosis; a potent antimycobacterial activity with a MIC = 9.52 μg mL⁻¹ was deduced from essential oil. Density functional theory (DFT) calculations were carried on batesiin (2). Calculated chemical shifts at B3LYP/6-31G(d,p) and MPW1PW91/6-31G+(d,p) showed much better correlations with the experimental data. Time dependent DFT at B3LYP/6-31G+(d,p) displayed a major absorption band 3.01 nm higher than the experimental value.

Conclusion

Cordia batesii can be considered as promising in search of compounds with antimalarial and antitubercular properties. DFT studies are very helpful when trying to learn more about the spectroscopic insights of a derivative of allantoin (1).

Efficacy of metal oxide nanoparticles as novel antimicrobial agents against multi-drug and multi-virulent Staphylococcus aureus isolates from retail raw chicken meat and giblets

Staphylococcus aureus is among the most common zoonotic pathogens originating from animals consumed as food, especially raw chicken meat (RCM). As far as we know, this might be the first report that explores the efficacy of metal oxide nanoparticles (MONPs), such as zinc peroxide nanoparticles (ZnO₂-NPs), zinc oxide nanoparticles (ZnO-NPs), and titanium dioxide nanoparticles (TiO₂-NPs) against multidrug resistant (MDR) and/or pandrug resistant (PDR) S. aureus strains with a strong biofilm-producing ability isolated from RCM and giblets. The overall prevalence of coagulase-positive staphylococci was 21%, with a contamination level range between 10² and 10⁴ CFU/g. The incidence of virulence genes See (21/36), pvl (16/36), clfA (15/36), sec (12/36), tst (12/36), and sea (11/36) among S. aureus strains were relatively higher those of seb, sed, fnbA, and fnbB. For antimicrobial resistance gene distribution, most strains harbored the blaZ gene (25/36), aacA-aphD gene (24/36), mecA gene (22/36), vanA gene (20/36), and apmA gene (20/36) confirmed the prevalence of MDR among S. aureus of RCM products. However, cfr (11/36), spc (9/36), and aadE (7/36) showed a relatively lower existence. The data of antibiogram resistance profiles was noticeably heterogeneous (25 patterns) with 32 MDR and four PDR S. aureus strains. All tested strains had a very high MAR index value (>0.2) except the P11 pattern (GEN, MXF, PMB), which showed a MAR index of 0.19. Among the strong biofilm-producing ability (BPA), 14 (70%) strains were isolated from wet markets, while only six strong BPA strains were isolated from supermarkets. The mean values of BPA ranged from 2.613 ± 0.04 to 11.013 ± 0.05. Clearly, ZnO₂-NPs show significant inhibitory activity against S. aureus strains compared with those produced by the action of ZnO-NPs and TiO₂-NPs. The results of anti-inflammatory activity suggest ZnO₂-NPs as a lead compound for designing an alternative antimicrobial agent against drug-resistant and strong biofilm-producing S. aureus isolates from retail RCM and giblets.

Retrospective Analysis on Antimicrobial Resistance Trends and Prevalence of β-lactamases in Escherichia coli and ESKAPE Pathogens Isolated from Arabian Patients during 2000-2020

The production of diverse and extended spectrum β-lactamases among Escherichia coli and ESKAPE pathogens is a growing threat to clinicians and public health. We aim to provide a comprehensive analysis of evolving trends of antimicrobial resistance and β-lactamases among E. coli and ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acine to bacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) in the Arabian region. A systematic review was conducted in Medline PubMed on papers published between January 2000 and February 2020 on countries in the Arab region showing different antibiotic resistance among E. coli and ESKAPE pathogens. A total of n = 119,144 clinical isolates were evaluated for antimicrobial resistance in 19 Arab countries. Among these clinical isolates, 74,039 belonged to E. coli and ESKAPE pathogen. Distribution of antibiotic resistance among E. coli and ESKAPE pathogens indicated that E. coli (n = 32,038) was the predominant pathogen followed by K. pneumoniae (n = 17,128), P. aeruginosa (n = 11,074), methicillin-resistant S. aureus (MRSA, n = 4370), A. baumannii (n = 3485) and Enterobacter spp. (n = 1574). There were no reports demonstrating Enterococcus faecium producing β-lactamase. Analyses revealed 19 out of 22 countries reported occurrence of ESBL (Extended-Spectrum β-Lactamase) producing E. coli and ESKAPE pathogens. The present study showed significantly increased resistance rates to various antimicrobial agents over the last 20 years; for instance, cephalosporin resistance increased from 37 to 89.5%, fluoroquinolones from 46.8 to 70.3%, aminoglycosides from 40.2 to 64.4%, mono-bactams from 30.6 to 73.6% and carbapenems from 30.5 to 64.4%. An average of 36.9% of the total isolates were reported to have ESBL phenotype during 2000 to 2020. Molecular analyses showed that among ESBLs and Class A and Class D β-lactamases, bla_CTX-M and bla_OXA have higher prevalence rates of 57% and 52.7%, respectively. Among Class B β-lactamases, few incidences of bla_VIM 27.7% and bla_NDM 26.3% were encountered in the Arab region. Conclusion: This review highlights a significant increase in resistance to various classes of antibiotics, including cephalosporins, β-lactam and β-lactamase inhibitor combinations, carbapenems, aminoglycosides and quinolones among E. coli and ESKAPE pathogens in the Arab region.

Effects of Brazilian green propolis extract on planktonic cells and biofilms of multidrug-resistant strains of Klebsiella pneumoniae and Pseudomonas aeruginosa

Propolis could represent an alternative therapeutic agent for targeting multidrug-resistant bacteria due to its antimicrobial potential. The effect of Brazilian green propolis (BGP) aqueous extract (AqExt) was evaluated on eight multidrug-resistant clinical strains of Klebsiella pneumoniae and Pseudomonas aeruginosa, as well as on one reference strain for each bacterial species. The minimum bactericidal concentration (MBC) was determined and optimal concentrations were further evaluated in comparison with 0.12% chlorhexidine. The natural extract was chemically characterized by HPLC-DAD analysis. The MBC values ranged between 3.12 and 27.5 mg ml^-1. Analysis of bacterial metabolic activity after treatment for 5 min with BGP-AqExt revealed a strong antimicrobial potential, similar to chlorhexidine. The extract comprised several active compounds including quercetin, gallic acid, caffeic and p-coumaric acid, drupani, galangin, and artepillin C. Altogether, the findings suggest that BGP-AqExt is fast and effective against multidrug-resistant strains of K. pneumoniae and P. aeruginosa in planktonic cultures and biofilms.

In Vitro Activity of Essential Oils Against Planktonic and Biofilm Cells of Extended-Spectrum β-Lactamase (ESBL)/Carbapenamase-Producing Gram-Negative Bacteria Involved in Human Nosocomial Infections

The aim of this study was to analyze the antibacterial activity of four essential oils (EOs), Melaleuca alternifolia, Eucalyptus globulus, Mentha piperita, and Thymus vulgaris, in preventing the development and spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa and carbapenemase (KPC)-producing Klebsiella pneumoniae. A total of 60 strains were obtained from the stock collection from the Microbiology Laboratory of Hesperia Hospital, Modena, Italy. Twenty ESBL-producing E. coli, 5 K. pneumoniae, 13 KPC-producing K. pneumoniae, and 20 MBL-producing P. aeruginosa were cultured and reconfirmed as ESBL and carbapenamase producers. Polymerase chain reaction was used for the detection of genes responsible for antibiotic resistance (ESBL and KPC/MBL). Antibacterial activity of the EOs was determined using the agar disk diffusion assay, and minimal inhibitory concentrations (MICs) were also evaluated. Lastly, adhesion capability and biofilm formation on polystyrene and glass surfaces were studied in 24 randomly selected strains. M. alternifolia and T. vulgaris EOs showed the best antibacterial activity against all tested strains and, as revealed by agar disk diffusion assay, M. alternifolia was the most effective, even at low concentrations. This effect was also confirmed by MICs, with values ranging from 0.5 to 16 µg/mL and from 1 to 16 µg/mL, for M. alternifolia and T. vulgaris EOs, respectively. The EOs' antibacterial activity compared to antibiotics confirmed M. alternifolia EO as the best antibacterial agent. T. vulgaris EO also showed a good antibacterial activity with MICs lower than both reference antibiotics. Lastly, a significant anti-biofilm activity was observed for the two EOs (*P < 0.05 and **P < 0.01 for M. alternifolia and T. vulgaris EOs, respectively). A good antibacterial and anti-biofilm activity of M. alternifolia and T. vulgaris EOs against all selected strains was observed, thus demonstrating a future possible use of these EOs to treat infections caused by ESBL/carbapenemase-producing strains, even in association with antibiotics.

Molecular characterization of virulence and drug resistance genes-producing Escherichia coli isolated from chicken meat: Metal oxide nanoparticles as novel antibacterial agents

Escherichia coli is a major global foodborne pathogen, infecting a wide range of animals and contaminating their meat products. E. coli, can lead to high morbidity and mortality with a huge economic loss especially if foodborne diseases are associated with multidrug resistant (MDR)- and multivirulent-producing pathogens. Due to the increased resistance to common antimicrobials used to treat livestock animals and human infections, the discovery of new and innovative nanomaterials are in high demand. Recently, metal oxides can be considered as effective inorganic agents with antimicrobial features. Hence, this study might be the first to evaluate the efficiency of metal oxide nanoparticles (MO-NPs) as novel antibacterial agents against MDR/multivirulent E. coli pathogens isolated from chicken meat. The occurrence of pathogenic E. coli was determined in fresh warm chicken meat parts (breast, thigh, liver and gizzard). Ninety-one of 132 (69%) chicken meat parts were Escherichia -positive with E. coli as the only species isolated. Out of identified 240 E. coli strains, 72.5% (174/240) were classified as MDR E. coli strains. Fifty-five profile patterns were obtained. From each pattern, one strain was randomly selected for further analysis of virulence and resistance genes. Extracted DNA was assessed for the presence of antibiotic resistance genes (bla_IMP-7, bla_IMP-25, bla_TEM, bla_SHV, bla_OXA-2, tetA, aadA, and aac(3)-IV) and virulence genes (stx1, stx2, hlyA, eaeA, aggR, eltB, estIb, papA, afa and hlyD). Clustering analyses revealed that 10 E. coli harboring the highest number of virulence and resistance genes were shifted together into one cluster designated as cluster X. The average activities of zinc peroxide nanoparticles (ZnO₂-NPs) were higher than that of zinc oxide nanoparticles (ZnO-NPs) and titanium dioxide nanoparticles (TiO₂-NPs) by 20% and 29%, respectively. The anti-inflammatory activity of ZnO₂-NPs in comparison with aspirin was assessed using membrane stabilization, albumin denaturation, and proteinase inhibition methods. Significant anti-inflammatory activity of ZnO₂-NPs was achieved at concentration levels of 500-1000 μg/ml. It seems that MO-NPs are effective alternative agents, since they exhibited a competitive antibacterial capability against MDR/multivirulent-producing E. coli pathogens isolated from chicken meat. Hence, ZnO₂-NPs are a promising nanoparticles-based material for controlling foodborne pathogens, thereby valued for food safety applications.

Treating drug-resistant wound pathogens with non-medicated dressings: an in vitro study

Objective:

To assess the in vitro antimicrobial performance of a non-medicated hydro-responsive wound dressing (HRWD) on the sequestration and killing of wound relevant microorganisms found on the World Health Organization (WHO) priority pathogens list.

Methods:

Suspensions of Pseudomonas aeruginosa, Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus (MRSA) were placed on petri dishes. Dressings were each placed on top, incubated for 30 minutes and then removed from the inoculated petri dish. The surface of the dressings previously in contact with the bacterial suspensions were placed directly onto a tryptone soy agar (TSA) plate and incubated for 24 hours. Dressings were then removed from the TSA plate and the level of bacterial growth on the plates was assessed. Sequestered microorganism viability was assessed using LIVE/DEAD viability kits and visualisation by epifluorescence.

Results:

Our results indicated that HRWDs sequester and retain Pseudomonas aeruginosa, Acinetobacter baumannii and MRSA within the dressing. Non-medicated HRWDs containing bound PHMB (polyhexamethylene biguanide, HRWD+PHMB) killed the microorganisms sequestered within the dressing matrix.

Conclusion:

These data suggest that non-medicated HRWD+PHMB is an effective against WHO priority pathogens and promoting goal of antimicrobial stewardship in wound care.

Syzygium aromaticum L.: Traditional herbal medicine against cagA and vacA toxin genes-producing drug resistant Helicobacter pylori

The Pan-Drug Resistant (PDR), Helicobacter pylori remains an intractable challenge in public health worldwide and this pathogenicity is mainly due to the presence of a cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA). On the other hand, plant extracts such as Syzygium aromaticum contain a diverse array of secondary metabolites, which could be potentially used to combat H. pylori pathogens. To our knowledge, this is the first report on the biomedical potential of S. aromaticum extract against cytotoxin-associated genes producing PDR H. pylori. In this investigation, out of 45 gastric antral biopsy specimens of dyspeptic patients, 20 strains were confirmed as H. pylori. Eight (40%) out of 20 strains were PDR H. pylori while the rest of the strains were Multi-Drug Resistant (MDR) strains. Genotypic analyses of PDR H. pylori strains showed that cagA and vacA genes were found to be 75% and 87.5%, respectively and m2s2 was the most common subtype of vacA gene. S. aromaticum showed a significant higher anti-H. pylori activity compared to that of Cinnamomum zeylanicum and Thymus vulgaris. Eugenol was the major phenolic compound (28.14%) detected in the methanolic extract of S. aromaticum. Clearly, results of the toxicological assessment confirmed the safety of S. aromaticum for use. Hence, these results suggest that S. aromaticum could be a new useful natural antimicrobial agent that could potentially combat cytotoxin genes-producing drug-resistant H. pylori. Moreover, these findings provide a scientific basis for the development of antimicrobial agents from traditional herbal medicines for gastroprotection against gastric ulcer.

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Helicobacter pylori remains an intractable challenge in public health worldwide.

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CagA and VacA genes are H. pylori pathogenicity dependent.

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Eight strains of H. pylori were proven to pan-drug resistant.

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The cagA and vacA genes were found to be 75% and 87.5%, respectively.

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Syzygium aromaticum extract showed a significant higher anti-H. pylori activity.

Lycium shawii Roem. & Schult.: A new bioactive antimicrobial and antioxidant agent to combat multi-drug/pan-drug resistant pathogens of wound burn infections

The Multidrug Drug Resistance (MDR) and Pan-Drug Resistance (PDR) remain an intractable challenge issue in public health, worldwide. Plant extracts-based biological macromolecules containing a diverse array of secondary metabolites could be potentially used as alternative approaches to control or limit MDR/PDR infections. Plants of the Solanaceae family exhibit a wide variety of secondary metabolites with antioxidant and antimicrobial properties, which render them a significant role in food and pharmaceutical applications. To our knowledge, this is the first report on phytochemical constituents, antioxidant, antimicrobial activities and in vivo toxicological safety of Lycium shawii leaf extracts. Results revealed that phenolics and flavonoids were found to be the most abundant compounds in all extracts. Antioxidant activity of extracts was measured using DPPH^• and ABTS^•+ assays and the methanol extract displayed superior scavenging activity (IC₅₀ = 0.06 and 0.007 mg/mL for DPPH^• and ABTS^•+, respectively). Results of the GC-MS analysis revealed the identity of 10 compounds. Moreover, in vivo toxicological assessment can confirm the safety of L. shawii for use. Overall, L. shawii leaves are a promising natural source for the development of novel antimicrobial and antioxidant agents that could potentially combat clinical MDR/PDR pathogens.

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The drug resistance remains an intractable challenge in public health.

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Phenolics and flavonoids were the most abundant compounds in all extracts.

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Methanol extract was the most antioxidant and antimicrobial agent.

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p-coumaric acid, apigenin, and fisetin are the major identified compounds.

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In vivo toxicological assessment can confirm the safety of L. shawii for use.

Investigation of common chemical components and inhibitory effect on GES-type β-lactamase (GES22) in methanolic extracts of Algerian seaweeds

This study aimed to investigate the total phenolic content (TPC), the identification of the common compounds by HPLC-ESI-MS and HPLC-ESI-MS-TOF and the inhibitory effects against class A-type β-lactamase (GES-22 variant, produced recombinantly) in methanolic extracts (MEs) of four Algerian seaweeds [Ulva intestinalis, Codium tomentosum, Dictyota dichotoma and Halopteris scoparia]. The TPC varied among the four species, ranging between 0.93 ± 0.65 and 2.66 ± 1.33 mg GAEs/g DW. C.tomentosum had higher total phenol content than other seaweeds while, all of them inhibited uncompetitively GES-22 activity in a dose-dependent manner. Nitrocefin was used as chromogenic substrate to evaluate the inhibitory effect on GES-22. The methanolic extract of D.dichotoma exhibited significant inhibitory effect on GES-22 (IC50 = 13.01 ± 0.046 μg/mL) more than clavulanate, sulbactam and tazobactam (classical β-lactam inhibitors) (IC50 = 68.38 ± 0.17 μg/mL, 52.68 ± 0.64 μg/mL, and 29.94 ± 0.01 μg/mL, respectively). IC50 of the other ME of U.intestinalis, C.tomentosum, and H.scoparia were 16.87 ± 0.10 μg/mL, 16.54 ± 0.048 μg/mL, and 25.72 ± 0.15 μg/mL, respectively. Except H. scoparia, other three seaweed extracts showed almost two times or more inhibition on GES-22. Furthermore, four common compounds in these MEs were identified, α-linolenic acid (C18:3ω3), linoleic acid (C18:2ω6), oleic acid (C18:1ω9), the eicosanoid precursors ''arachidonic acid'' (C20:4ω6). Baicalein (C15H10O5) was identified in U.intestinalis and D.dichotoma seaweeds. The fact that all seaweed extracts inhibited the GES-22 better than commercial samples makes these seaweeds candidate for discovering new inhibitors against β-lactamases. Besides that, they contain important components with potential health benefits.

Pharmaceutical Potential of a Novel Chitosan Derivative Schiff Base with Special Reference to Antibacterial, Anti-Biofilm, Antioxidant, Anti-Inflammatory, Hemocompatibility and Cytotoxic Activities

PURPOSE

Chitosan and its derivatives possess several unique properties relevant in the field of pharmaceutics and medicinal chemistry. This study aimed to evaluate the pharmaceutical performance of an innovative chitosan derivative, methyl acrylate chitosan bearing p-nitrobenzaldehyde (MA*CS*pNBA) Schiff base.

METHODS

The antibacterial activity of MA*CS*pNBA was tested against multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria using agar-well diffusion method. Anti-biofilm formation was analyzed using a microtitre plate. Antioxidant assays were performed to assess the scavenging activity of MA*CS*pNBA using DPPH, hydrogen peroxide, superoxide together with its reducing power activity. Anti-inflammatory activity was evaluated by albumin denaturation, membrane stabilization, and proteinase inhibition methods. MA*CS*pNBA was tested for its hemolytic efficiency on human erythrocytes. Cytotoxicity of MA*CS*pNBA was evaluated by MTT assay.

RESULTS

MA*CS*pNBA showed a significant performance as an antibacterial candidate against MDR bacteria, anti-biofilm, antioxidant and anti-inflammatory biomaterial, evidencing hemocompatibility and no cytotoxicity. It exhibited a significant negative correlation with biofilm formation by the MDR-PA-09 strain. Biological activities were found to be significantly concentration-dependent.

CONCLUSIONS

the newly chitosan derivative MA*CS*pNBA showed to be promising for pharmaceutical applications, expanding the treatment ways toward skin burn infections since it allied excellent antibacterial, anti-biofilm, antioxidant, anti-inflammatory, hemocompatibility and absence of cytotoxic activities.