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  • Open access
  • 53 Reads
Susceptibility of Campylobacter strains to selected natural products and frontline antibiotics

Campylobacter species have developed resistance to existing antibiotics. The development of alternative therapies is therefore a necessity. This study evaluated the susceptibility of Campylobacter strains to selected natural products (NPs) and frontline antibiotics. Two C. jejuni strains (ATCC® 33560TM and MT947450) and two C. coli strains (ATCC® 33559TM and MT947451) were used. The antimicrobial potential of NPs including plant extracts, essential oils, and pure phytochemicals was evaluated by broth microdilution. The growth was measured by spectrophotometry and iodonitrotetrazolium chloride. Antibiotic resistance genes (tet(O) and gyrA) were characterized at the molecular level. The minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) ranged from 25-1600 µg/mL. Cinnamon oil, trans-cinnamaldehyde, clove oil, eugenol, and baicalein had the lowest MIC and MBC values (25-100 µg/mL). MT947450 and MT947451 were sensitive to erythromycin and gentamicin but resistant to quinolones and tetracycline. Mutations in gyrA and tet(O) genes from resistant strains were confirmed by sequencing. The findings showed that NPs are effective against drug-sensitive and resistant Campylobacter strains. The resistance to antibiotics was confirmed at phenotypic and genotypic levels. This merits further studies to decipher the action mechanisms and synergistic activities of NPs.

  • Open access
  • 56 Reads
Action potential of aminonitriles in active sites of carbonic anhydrase isoforms

Heterocyclic compounds have gained notoriety in the pharmaceutical universe after studies in numbers. Such compounds make the spectrum of action and development of countless drugs more flexible, and may become a viable alternative for, mainly, or antimicrobial development. In this perspective, the aminonitriles that lead the subgroup of notoriety in this advance are inserted, since, through their characteristic characteristics, an example of stability and resistance to hydrolysis, offers a forceful interaction with pathogens. Also, this relationship is closely related to enzymatic interactions of metabolic functioning, mainly not that it concerns the functioning of carbonic anhydrase and its isoforms. Given this, it is inferred to optimize and understand the bibliographic data already available to expand the field of compound actions, thereby characterizing the recognition of its possibilities for applicability in various pathologies.

  • Open access
  • 99 Reads
Antimicrobial properties of essential oils extracted from plants of the Asteraceae family against Herpes Simplex Viruses (HSV-1, HSV-2): a systematic review

Aim. To study the antimicrobial properties of essential oils extracted from plants of the Asteraceae family against Herpes Simplex Viruses type 1 and 2 (HSV-1, HSV-2).

Methods. A systematic literature review was carried out in seven online repositories (ISI Web of Science, PubMed, EMBASE, Scopus, Google Scholar, CINAHL and Cochrane Library) to retrieve all relevant human and laboratory studies. All databases were screened up to May 1st, 2020.

Results. After database search, 11 studies were included in this review. Retrieved evidence exclusively derived from in vitro studies conducted in laboratory models of Vero (or similar) cell lines infected with HSV-1 or HSV-2. Analyzed essential oils were obtained from Artemisia arborescens, Artemisia douglasiana, Artemisia kermanensis, Chrysanthemum trifurcatum, Eupatorium arnottianum, Eupatorium catarium, Matricaria recutita, Pulicaria vulgaris and Santolina insularis. While for Chrysanthemum trifurcatum no significant antiviral effect was detected, an inhibitory action against HSV-1 or HSV-2 was demonstrated for the other oils. The majority of antiviral effects were attributed to a direct inactivation of free virions and to the inhibition of viral penetration into host cells. Nevertheless, intracellular mechanisms of action were not fully excluded, especially for Santolina insularis. Oils obtained from Matricaria recutita and Santolina insularis also had a high Selectivity Index, thus theoretically outlining a quite safe profile for their potential uses in vivo.

Discussion. Essential oils extracted from different plants of the Asteraceae family exhibit a significant antimicrobial activity against HSV-1 and HSV-2. In particular, the majority of retrieved evidence, based on in vitro studies, supports the efficacy of Artemisia spp., Matricaria recutita and Santolina insularis. Further studies on the topic are advised.

  • Open access
  • 34 Reads
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There is a growing interest on DHA derivatives compounds in recent years, due to an establish antibacterial, antifungal, anti-inflammatory and anticancer activities, several researches were performed on ligand precursor and transition metal complexes derivatives. [1,4]

Efficient and easy access to different classes family using dehydroacetic acid DHA as starting materials is reported, the obtained compounds were fully characterized by UV-Vis and FT-IR spectroscopy in addition to X ray diffraction on monocristal, several in vitro biological tests were also performed on this metal chelates to explore its therapeutically potential in order to continue further investigations and exploring them as new target drugs. In this case, antioxidant activities: ATBS, B-carotene, Metal chelate essays CCA and Fe++, enzymatic activity: urease inhibitors and antimicrobial activity against several bacterial and fungal referenced strains, exhibit interesting results which will be developed in this work .

  • Open access
  • 29 Reads
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The development of bio-guided trials on medicinal plants therapeutic target has increased recent years through pharmacology that is interested in discovering new molecules expressing a therapeutic activity and development of useful drugs by selecting the most active fraction and isolates the active compound responsible of the therapeutically effect.

In the present work Cinnamomum zeylanicum gender a wildly used as spice and medicinal plant, is investigated on both chemical and biological field, which revealed its richness in secondary metabolites. Therefore, we perform identification and quantification analysis of main bioactive compounds in order to subject it to bio guided tests using several solvents' polarities in order to evaluate its in vitro antimicrobial potential. To achieve our objective, we used qualitative and quantitative methods to identify the components of the obtained extracts. The in vitro antimicrobial effect of the medicinal plant was evaluated by disk diffusion method on several ATCC microbial strains and which gave almost very interesting results for all tested pathogens.

  • Open access
  • 31 Reads
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In the framework of enhancing medicinal plants of the Mediterranean flora, the present work investigates phytochemical screening of different parts’ extracts of a wild medicinal plant from Asteraces family: roots, leaves, flowers and aerial parts. It also highlights the quantification of the main secondary metabolites; total polyphenols and flavonoids and its correlation with in vitro antioxidant and antimicrobiol activities. Biological tests have shown encouraging results for the antioxidant activities namely: reducing power, hydrogen peroxide and hydroxyl radical scavenging, and exhibit flowers extract as promising source of phenols and potent antioxidants with the ability of breaking hydroxyl free radical chain generating, the main responsible of oxidative stress, on the other hand antibacterial and antifungal activities tested by discs diffusion method on agar medium, were carried out; and the effectiveness of tested extracts has been demonstrated against five pathogen bacterial and fungal referential strains. Obtained results exhibit aerial part as better phenols sources, whereas roots extract showed better in vitro antimicrobial activity. Obtained results showed nice correlation and open large perspectives on bioactive compounds assessment, SAR studies and clinical trials.

  • Open access
  • 35 Reads

In recent year, the chemistry of ferrocene and the design of new compounds containing the ferrocene unit, has received a surge in interest, owing to their utility in many fields such as organic synthesis, catalysis and biotechnology material. In the framework, of attending a new multifunctional ferrocenyl derivatives, two precurssors namely DMHF and a carbaldehyde ferrocene functionalized in 1,2 position by thiophosphine function were fully characterized by HRMS, IR, NMR 1H, 13C, and UV spectroscopy, then were in vitro tested for antibacterial activity against two gram+ (Staphylococcus aureus, Bacillus sp), three gram- (E.coli, Klebsiella pneumonia, Morganella morganii )referential strains and Penicillium Sp fungi using disk diffusion method on solid medium MH and Sabouraud respectively. Obtained results were compared to antibiogram and reveled an interesting antimicrobial potent varying from 7 to 10mm of inhibition for DMHF and 7 to 15mm of inhibition for 1,2 dithiophosphine ferrocene compounds, which indicates mostly an improvement of antimicrobial activity with chiral substitution of ferrocene moiety with thiophosphine function, this encourage future investigations on chirality and substitution role in the improvement of antimicrobial activity.

  • Open access
  • 41 Reads
Transferable Extended-Spectrum β-Lactamase (ESBL) Plasmids in Enterobacteriaceae from Irrigation Water

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae are considered serious threats to human health. Water used for irrigation of fresh produce can transmit such antibiotic resistant bacteria (ARB) directly to edible plant parts, which in turn can transmit ARB to the consumer, where the ingested ARB can interact with the gut microbiome. The aim of our study therefore was to assess the potential of ESBL-producing Enterobacteriaceae from irrigation water to transfer resistance to susceptible Escherichia coli.

We screened 19 ESBL-producing E. coli, Enterobacter cloacae, and Citrobacter freundii isolated from irrigation water for their ability to transmit resistance to third-generation cephalosporins on solid agar as well as in liquid culture. Additionally, donor strains and resulting transconjugants were genome-sequenced (PacBio and Illumina) to identify the underlying antibiotic resistance genes (ARGs) and plasmids. Additionally, phenotypic resistance patterns of donors and corresponding transconjugant strains were compared.

Of the 19 ESBL-producing Enterobacteriaceae, five E. coli were able to transfer resistance to susceptible recipient E. coli, with transmission efficiency ranging from 2.3 × 10−9 to 4.1 × 10−5 transconjugants per recipient cell. The obtained transconjugants all displayed ESBL-producing phenotype, as determined by broth microdilution. Genome-sequencing revealed that each of the five donors which yielded transconjugants carried a plasmid containing a β-lactamase gene of the CTX-M family, which encode class A ESBLs conferring resistance to third-generation cephalosporins. The most frequent ESBL gene was blaCTX-M-1 (3 of 5), and the corresponding plasmids all belonged to incompatibility group I1 (IncI1), while the other two plasmids carried IncFIA and/or IncFIB. Importantly, all but one of the five plasmids encoded additional ARGs (up to nine in total). Finally, all ARGs encoded by the blaCTX-M-carrying plasmid could be detected in the genome sequences of the respective transconjugants. Overall, our findings highlight the importance of monitoring water quality to avoid contamination of irrigated produce with conjugative ESBL-encoding plasmids.

  • Open access
  • 66 Reads
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Purpose: Urinary tract infections are the second most common children’s infections. The prevalence in Russian Federation is 18 cases in 1000. Also, spreading of antimicrobials resistance among children's UTI poses a high epidemiological threat.

Materials and methods: Retrospective analysis was performed with 163 sequentially collected midstream portion of urine. Samples were collected from patients of 4 weeks to 17 years in FSAI of the Ministry of Health of the Russian Federation «NMR Center for Children's Health» during 2019. Bacteriological tests were performed on URISELECT™ (Bio-Rad Laboratories, USA) medium. Species were determined by MALDI-TOF MS (Bruker Daltonics, Germany) and bacteriological analyzer Vitek 2 (BioMerieux, France). Antimicrobial susceptibility tests were performed using disc-diffusion method (Bio-Rad, USA) and E-tests (BioMerieux, France). DNA extraction was performed using «RIBO-prep» (AmpliSens, Russia). Detection of antimicrobial resistance gene determinants was performed using quantitative real-time PCR assays: «AmpliSens® MDR MBL-FL», «AmpliSens® MDR KPC-OXA-48-FL», «AmpliSens® ESBL CTX-M», «AmpliSens® MDR A.b.-OXA-FL», and «AmpliSens® MDR VRE-FL» (all Central Research Institute of Epidemiology, Russia).

Results and Discussion: Species of uropathogens were identified in 69 samples while others being classified as «gut flora» (n=14), «coccus flora» (n=10) or «mixed flora» (n=70). The most prevalent uropathogens were Escherichia coli (24.7%) and Enterococcus faecalice (20.3%). Genes of CTX-M-like group, including blaCTX-M-1-like, blaCTX-M-2-like, blaCTX-M-8-like, and blaCTX-M-9-like, were determined in 33%, blaVIM in 6%, blaIMP in 1%, blaNMD in 4%, and blaOXA-48-like in 3% of studied samples. No blaKPC genes were identified. In all 69 samples with identified species, antimicrobial resistance profile, determined by microbiological methods, was in accordance with found gene determinants, including resistance to penicillins, cephalosporins, carbapenems, and monobactams.

Conclusions: It is of great importance to introduce antimicrobial resistance genes determinants testing in clinical practice. It would provide the opportunity to determine correct in-time treatment for antimicrobials resistant bacteria infections.

  • Open access
  • 45 Reads
Cinnamon leaf oil release from chitosan microcapsules embedded within a sodium alginate-gelatin hydrogel-like film for the inhibition of multi-drug resistant bacteria
Pseudomonas aeruginosa-derived infections are considered a public health problem once that P. aeruginosa is stated as a human pathogen highly resistant to antibiotics. Recently, essential oils (EOs) have been reported as an alternative to antibiotics. Polymeric microcapsules can include antimicrobial agents at the core and be surrounded by a polymeric shell, usually containing polysaccharides like chitosan (CS), aiming to work as drug carriers and protecting the encapsulated biomolecule from the surrounding environment. Hydrogel-like films are commonly produced to incorporate microcapsules because of their high porosity, that enables a high permeability of oxygen, nutrients and metabolites. Sodium alginate (SA) and gelatin (GN) are polymers that are frequently applied in the production of films. In this study, a delivery platform was developed for the controlled release of cinnamon leaf oil (CLO) entrapped in CS microcapsules produced via ionotropic gelation. CS solution was prepared without pH adjustment (CS1) and with pH adjusted to 5.0 (CS4), which according to the literature improves the polymer stability for microencapsulation. The microcapsules were then incorporated in hydrogel-like films, composed of a combination of SA and GN. Results confirmed an effective incorporation of CS microcapsules, containing CLO, within SA/GN films, as well as a continuous release of the entrapped CLO during 24h. Time kill kinetics tests showed that during the first hour of interaction with the CLO-containing films bacteria continued to grow. However, as the CLO release from the films increased, its action against the bacteria also improved with a >99% elimination. CS1 microcapsules were deemed more effective, due to their enhanced CLO release profile and antimicrobial action. All qualitative and quantitative antimicrobial tests proved the potential of CLO loaded films for the inhibition of multi-drug resistant bacteria.