In Vitro Activity of Propolis on Oral Microorganisms and Biofilms

Natural products are being discussed as alternatives to commonly used chemicals in antimicrobial therapy. The study aimed to investigate the antimicrobial activity of propolis against microbial species associated with caries, periodontal disease, and Candida infections. Two commercially available ethanolic extracts of Brazilian and one of European propolis (EEP) were used. The minimal inhibitory concentrations (MIC) of propolis and controls against eight microbial strains were determined. Scanning and transmission electron microscopy (SEM and TEM) images visualized the effect of propolis on microorganisms. Subsequently, the activity on three different multi-species biofilms (both formation and existing biofilms) was assessed. All MIC values of the Brazilian EEPs were low against the tested oral species (≤0.1 mg/mL–3.13 mg/mL propolis (Candida albicans)). The European EEP had slightly higher MICs than the Brazilian EEPs. The SEM and TEM images suggest an interaction of propolis with the microbial cell wall. The European EEP exhibited the strongest effect on retarding biofilm formation, whereas the Brazilian EEPs were highly active against preformed biofilms (100 mg/mL propolis of both EEPs reduced colony forming unit counts always by more than 6 log10). The antimicrobial and anti-biofilm activities point to the potential of propolis as an adjunct in oral health care products.

Download Full-text

Susceptibility of Candida spp. clinical isolates to antimycotics and disinfectants

Open Life Sciences ◽

10.2478/s11535-010-0068-3 ◽

2010 ◽

Vol 5 (6) ◽

pp. 821-826

Author(s):

Monika Staniszewska ◽

Beata Rozbicka ◽

Aleksandra Rajnisz ◽

Ewa Bocian ◽

Ewa Wasińska ◽

...

Keyword(s):

Clinical Isolates ◽

Cross Resistance ◽

Biocidal Activity ◽

Candida Spp ◽

In Vitro Susceptibility ◽

Minimal Inhibitory Concentrations ◽

Antiseptic Agent ◽

Resistant Strains ◽

Candida Infections

AbstractThe incidence of candidiasis among immunocompromised patients and emergence of antimycotics resistant strains has increased significantly. The aims of this study were: to examine the in vitro activity of antimycotics and biocides against Candida clinical isolates; to detect cross-resistance of fungi to these preparations and to estimate whether disinfectants applied in hospital areas are active against clinical Candida isolates. In vitro susceptibility of 102 Candida isolates to eight antimycotics was examined by Etest and ATB Fungus. Sensitivity of these strains to four disinfectants and an antiseptic agent was tested according to EN 1275:2005. Amphotericin B, caspofungin and 5-fluorocytosine were the most effective antimycotics against all Candida isolates. Resistance to itraconazole and fluconazole was observed among C. krusei and C. glabrata. The MICs (Minimal Inhibitory Concentrations) for ketoconazole, voriconazole and posaconazole against Candida albicans ranged: 0.003 - >32 μg/ml and one strain was resistant to three agents tested. All analysed Candida strains were sensitive to biocides containing either chlorine, aldehyde, alcohol mixtures, glucoprotamin or chlorhexidine gluconate with isopropanol. Sensitivity to these agents was observed at concentrations lower than those concentrations recommended by manufacturers to achieve proper biocidal activity to those preparations. Our data suggest that these disinfectants can be effectively applied in clinical wards to prevent nosocomial Candida infections.

Download Full-text

Comparative study of the action of fluoroquinolones and vancomycin on biofilms of Staphylococcus strains isolated from infections of peritoneal dialysis catheters

Current Research in Microbiology and Infection ◽

10.31559/crmi2021.2.1.1 ◽

2021 ◽

Vol 2 (1) ◽

pp. 1-4

Author(s):

A. Rabhi ◽

S. Mahrane ◽

S.L. Nouar ◽

R. Boushaki ◽

A.N. Benkherif ◽

...

Keyword(s):

Peritoneal Dialysis ◽

Comparative Study ◽

Biofilm Formation ◽

Microtiter Plate ◽

Vitro Activity ◽

In Vitro Activity

Background: catheter mediated infections are mainly caused by Staphylococci, the treatment of these infections is challenging because of biofilm formation. Methods: A microtiter plate biofilm assay was used to study the in vitro activity of Vancomycin, Ofloxacin and Levofloxacin on preformed biofilms of 30 stains of Staphylococcus isolated from peritoneal dialysis catheters and fluids at concentrations like those used intraperitoneally. Results: The in vitro action of the three antibiotics on preformed biofilms was statistically significant. it was significantly higher for Ofloxacin and Levofloxacin rather than that of Vancomycin. Discussion: the results demonstrate the effectiveness of the three antibiotics at concentrations like those used intraperitoneally and the superiority of Fluoroquinolones activity on Staphylococcal biofilms, these results correlate with the conclusions of other authors.

Download Full-text

Candida albicans Biofilm Inhibition by Two Vaccinium macrocarpon (Cranberry) Urinary Metabolites: 5-(3′,4′-DihydroxyPhenyl)-γ-Valerolactone and 4-Hydroxybenzoic Acid

Microorganisms ◽

10.3390/microorganisms9071492 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1492

Author(s):

Emerenziana Ottaviano ◽

Giovanna Baron ◽

Laura Fumagalli ◽

Jessica Leite ◽

Elisa Adele Colombo ◽

...

Keyword(s):

Biofilm Formation ◽

Urinary Metabolites ◽

Hydroxybenzoic Acid ◽

Inhibitory Effects ◽

Candida Spp ◽

Biofilm Inhibition ◽

Strain Sc5314 ◽

Candida Infections ◽

Dose Dependent

Candida spp. are pathobionts, as they can switch from commensals to pathogens, responsible for a variety of pathological processes. Adhesion to surfaces, morphological switch and biofilm-forming ability are the recognized virulence factors promoting yeast virulence. Sessile lifestyle also favors fungal persistence and antifungal tolerance. In this study, we investigated, in vitro, the efficacy of two urinary cranberry metabolites, 5-(3′,4′-dihydroxy phenyl)-γ-valerolactone (VAL) and 4-hydroxybenzoic acid (4-HBA), in inhibiting C. albicans adhesion and biofilm formation. Both the reference strain SC5314 and clinical isolates were used. We evaluated biomass reduction, by confocal microscopy and crystal violet assay, and the possible mechanisms mediating their inhibitory effects. Both VAL and 4-HBA were able to interfere with the yeast adhesion, by modulating the expression of key genes, HWP1 and ALS3. A significant dose-dependent reduction in biofilm biomass and metabolic activity was also recorded. Our data showed that the two cranberry metabolites VAL and 4-HBA could pave the way for drug development, for targeting the very early phases of biofilm formation and for preventing genitourinary Candida infections.

Download Full-text

In vitro activity of biapenem and other carbapenems against Russian clinical isolates of Pseudomonas aeruginosa, Acinetobacter spp., and Enterobacterales

Clinical Microbiology and Antimicrobial Chemotherapy ◽

10.36488/cmac.2021.3.280-291 ◽

2021 ◽

Vol 23 (3) ◽

pp. 280-291

Author(s):

Roman S. Kozlov ◽

Ilya S. Azyzov ◽

Andrey V. Dekhnich ◽

Nataly V. Ivanchik ◽

Alexey Yu. Kuzmenkov ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Central Research Institute ◽

Vitro Activity ◽

Clinical Isolates ◽

Central Research ◽

In Vitro Activity ◽

Mechanisms Of Resistance ◽

Minimal Inhibitory Concentrations ◽

Acinetobacter Spp

Objective. To evaluate in vitro activity of biapenem and other clinically available carbapenems against Russian clinical isolates of Enterobacterales, Pseudomonas aeruginosa и Acinetobacter spp., including isolates with acquired fermentative mechanisms of resistance to β-lactams. Materials and Methods. A total of 3139 Enterobacterales isolates, 793 P. aeruginosa isolates and 634 Acinetobacter spp. isolates from hospitalized patients in 63 hospitals from 35 Russian cities were included in the study during 2018-2019. Minimal inhibitory concentrations (MIC) for biapenem and other antimicrobials were determined in accordance with ISO 20776-1:2006. Carbapenemases genes were detected by commercially available real-time PCR kits AmpliSens® MDR KPC/OXA-48-FL and AmpliSens® MDR MBL-FL (Central Research Institute of Epidemiology, Russia). Data analysis and reporting was performed using AMRcloud online platform (www.amrcloud.net). Results. For all tested Escherichia coli isolates MIC50/90 were 0.06/0.125 mg/l for biapenem, 0.125⁄0.25 mg/l for imipenem, and 0.06/0.06 mg/l for meropenem. When MIC50/90 for ertapenem (0.015/0.125 mg/l for all isolates tested) were comparable to those of biapenem, a greater number of nosocomial E. coli isolates had MIC >4 mg/l for ertapenem (3.6%) than for biapenem (2.6%). MIC50/90 of Klebsiella pneumoniae for biapenem were 0.5⁄16 mg/l, for both imipenem and meropenem – 0.5⁄32 mg/l, for ertapenem – 2⁄32 mg/l. Resistance to oxyimino-β-lactams had no significant influence on activity of biapenem against Enterobacterales isolates. For 321 carbapenemase-producing K. pneumoniae isolates (ОХА-48 – 63.9%, NDM – 27.7%) biapenem has shown no advantages over imipenem and meropenem. МПК50/90 for nosocomial and community-acquired P. aeruginosa isolates were 8⁄64 mg/l and 0,5⁄16 mg/l for biapenem, 8⁄128 mg/l and 1⁄16 mg/l – for imipenem, 16⁄64 mg/l and 0,5⁄32 mg/l – for meropenem. All carbapenems, including biapenem, had very low in vitro activity against carbapenemaseproducing P. aeruginosa isolates. МПК50/90 of Acinetobacter spp. were 64⁄128 mg/l for biapenem, 64⁄128 mg/l – for imipenem, and 128⁄128 mg/l – for meropenem. Conclusions. According to the MIC distributions and MICs50/90 values independently of the presence of fermentative mechanisms of resistance to β-lactams, in vitro activity of biapenem against Russian clinical isolates of Enterobacterales, P. aeruginosa and Acinetobacter spp. was comparable to those of imipenem and meropenem.

Download Full-text

Killing of Trypanozoon Parasites by the Equine Cathelicidin eCATH1

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01127-15 ◽

2016 ◽

Vol 60 (5) ◽

pp. 2610-2619 ◽

Cited By ~ 8

Author(s):

S. Cauchard ◽

N. Van Reet ◽

P. Büscher ◽

D. Goux ◽

J. Grötzinger ◽

...

Keyword(s):

Mammalian Cells ◽

Trypanosoma Evansi ◽

Host Defense Peptides ◽

Content Type ◽

Sytox Green ◽

Highly Active ◽

Transmission Electron ◽

Mitochondrial Alteration ◽

Plasma Membrane Permeabilization

ABSTRACTTrypanozoonparasites infect both humans, causing sleeping sickness, and animals, causing nagana, surra, and dourine. Control of nagana and surra depends to a great extent on chemotherapy. However, drug resistance to several of the front-line drugs is rising. Furthermore, there is no official treatment for dourine. Therefore, there is an urgent need to develop antiparasitic agents with novel modes of action. Host defense peptides have recently gained attention as promising candidates. We have previously reported that one such peptide, the equine antimicrobial peptide eCATH1, is highly active against equine Gram-positive and Gram-negative bacteria, without cytotoxicity against mammalian cells at bacteriolytic concentrations. In the present study, we show that eCATH1 exhibits anin vitro50% inhibitory concentration (IC50) of 9.5 μM againstTrypanosoma brucei brucei,Trypanosoma evansi, andTrypanosoma equiperdum. Its trypanocidal mechanism involves plasma membrane permeabilization and mitochondrial alteration based on the following data: (i) eCATH1 induces the rapid influx of the vital dye SYTOX Green; (ii) it rapidly disrupts mitochondrial membrane potential, as revealed by immunofluorescence microscopy using the fluorescent dye rhodamine 123; (iii) it severely damages the membrane and intracellular structures of the parasites as early as 15 min after exposure at 9.5 μM and 5 min after exposure at higher concentrations (19 μM), as evidenced by scanning and transmission electron microscopy. We also demonstrate that administration of eCATH1 at a dose of 10 mg/kg toT. equiperdum-infected mice delays mortality. Taken together, our findings suggest that eCATH1 is an interesting template for the development of novel therapeutic agents in the treatment of trypanosome infections.

Download Full-text

Mild Heating of Amphotericin B-Desoxycholate: Effects on Ultrastructure, In Vitro Activity and Toxicity, and Therapeutic Efficacy in Severe Candidiasis in Leukopenic Mice

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.6.1598-1603.2000 ◽

2000 ◽

Vol 44 (6) ◽

pp. 1598-1603 ◽

Cited By ~ 23

Author(s):

Els W. M. van Etten ◽

Wim van Vianen ◽

Patty Roovers ◽

Peter Frederik

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Amphotericin B ◽

Therapeutic Efficacy ◽

Fungal Infections ◽

Laser Diffraction ◽

In Vitro Activity ◽

New Approach ◽

Transmission Electron

ABSTRACT Heated (20 min at 70°C) amphotericin B-desoxycholate (hAMB-DOC) was further characterized, as was another formulation obtained after centrifugation (60 min, 3000 × g), hcAMB-DOC. Conventional AMB-DOC consisted of individual micelles (approximately 4 nm in diameter) and threadlike aggregated micelles, as revealed by cryo-transmission electron microscopy. For both hAMB-DOC and hcAMB-DOC, pleiomorphic cobweb structures were observed with a mean particle size of approximately 300 nm as determined by laser diffraction. The potent antifungal activity of AMB-DOC against Candida albicans is not reduced by heating. Effective killing of C. albicans(>99.9% within 6 h) was obtained at 0.1 mg/liter with each of the AMB formulations. For AMB-DOC, hAMB-DOC, and hcAMB-DOC, cation release (86Rb+) from C. albicans of ≥50% was observed at 0.8, 0.4, and 0.4 mg/liter, respectively. After heating of AMB-DOC, toxicity was reduced 16-fold as determined by red blood cell (RBC) lysis. For AMB-DOC, hAMB-DOC, and hcAMB-DOC, hemolysis of ≥50% was observed at 6.4, 102.4, and 102.4 mg/liter, respectively. In contrast, AMB-DOC and its derivates showed similar toxicities in terms of cation release from RBC. For AMB-DOC, hAMB-DOC, and hcAMB-DOC, cation release (86Rb+) of ≥50% was observed at 1.6, 0.8, and 0.8 mg/liter, respectively. In persistently leukopenic mice with severe invasive candidiasis, higher dosages of both hAMB-DOC and hcAMB-DOC were tolerated than those of conventional AMB-DOC (3 versus 0.8 mg/kg of body weight, respectively), resulting in significantly improved therapeutic efficacy. In conclusion, this new approach of heating AMB-DOC may be of great value for further optimizing the treatment of severe fungal infections.

Download Full-text

Ultrashort Peptide Bioconjugates Are Exclusively Antifungal Agents and Synergize with Cyclodextrin and Amphotericin B

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00468-11 ◽

2011 ◽

Vol 56 (1) ◽

pp. 1-9 ◽

Cited By ~ 29

Author(s):

Christopher J. Arnusch ◽

Hannah Ulm ◽

Michaele Josten ◽

Yana Shadkchan ◽

Nir Osherov ◽

...

Keyword(s):

Vitamin E ◽

Amphotericin B ◽

Selective Toxicity ◽

Content Type ◽

Biologically Relevant ◽

Highly Active ◽

Transmission Electron ◽

Permeability Studies

ABSTRACTMany natural broad-spectrum cationic antimicrobial peptides (AMPs) possess a general mode of action that is dependent on lipophilicity and charge. Modulating the lipophilicity of AMPs by the addition of a fatty acid has been an effective strategy to increase the lytic activity and can further broaden the spectrum of AMPs. However, lipophilic modifications that narrow the spectrum of activity and exclusively direct peptides to fungi are less common. Here, we show that short peptide sequences can be targeted to fungi with structured lipophilic biomolecules, such as vitamin E and cholesterol. The conjugates were active againstAspergillus fumigatus,Cryptococcus neoformans, andCandida albicansbut not against bacteria and were observed to cause membrane perturbation by transmission electron microscopy and in membrane permeability studies. However, forC. albicans, selected compounds were effective without the perturbation of the cell membrane, and synergism was seen with a vitamin E conjugate and amphotericin B. Moreover, in combination with β-cyclodextrin, antibacterial activity emerged in selected compounds. Biocompatibility for selected active compounds was testedin vitroandin vivousing toxicity assays on erythrocytes, macrophages, and mice.In vitrocytotoxicity experiments led to selective toxicity ratios (50% lethal concentration/MIC) of up to 64 for highly active antifungal compounds, and noin vivomurine toxicity was seen. Taken together, these results highlight the importance of the conjugated lipophilic structure and suggest that the modulation of other biologically relevant peptides with hydrophobic moieties, such as cholesterol and vitamin E, generate compounds with unique bioactivity.

Download Full-text

Campylobacter jejuni 81-176 forms distinct microcolonies on in vitro-infected human small intestinal tissue prior to biofilm formation

Microbiology ◽

10.1099/mic.0.039867-0 ◽

2010 ◽

Vol 156 (10) ◽

pp. 3079-3084 ◽

Cited By ~ 24

Author(s):

Graham Haddock ◽

Margaret Mullin ◽

Amanda MacCallum ◽

Aileen Sherry ◽

Laurence Tetley ◽

...

Keyword(s):

Campylobacter Jejuni ◽

Biofilm Formation ◽

Target Tissue ◽

Apical Surface ◽

Intestinal Tissue ◽

Time Points ◽

Transmission Electron ◽

Large Numbers ◽

Ileal Tissue

Human small and large intestinal tissue was used to study the interaction of Campylobacter jejuni with its target tissue. The strain used for the study was 81-176 (+pVir). Tissue was processed for scanning and transmission electron microscopy, and by immunohistochemistry for light microscopy. Organisms adhered to the apical surface of ileal tissues at all time points in large numbers, in areas where mucus was present and in distinct groups. Microcolony formation was evident at 1–2 h, with bacteria adhering to mucus on the tissue surface and to each other by flagellar interaction. At later time points (3–4 h), biofilm formation on ileal tissue was evident. Flagellar mutants did not form microcolonies or biofilms in tissue. Few organisms were observed in colonic tissue, with organisms present but not as abundant as in the ileal tissue. This study shows that C. jejuni 81-176 can form microcolonies and biofilms on human intestinal tissue and that this may be an essential step in its ability to cause diarrhoea in man.

Download Full-text

Molecular characteristics and in vitro effects of antimicrobial combinations on planktonic and biofilm forms of Elizabethkingia anophelis

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkab018 ◽

2021 ◽

Author(s):

Hung-Jen Tang ◽

Yi-Tsung Lin ◽

Chi-Chung Chen ◽

Chih-Wei Chen ◽

Ying-Chen Lu ◽

...

Keyword(s):

Synergistic Effect ◽

Biofilm Formation ◽

Antimicrobial Agents ◽

Synergistic Effects ◽

Resistance Mechanism ◽

Vitro Activity ◽

Molecular Characteristics ◽

In Vitro Activity ◽

Antibiotic Combination

Abstract Objectives To investigate the in vitro activity of antibiotics against clinical Elizabethkingia anophelis isolates and to find a suitable antibiotic combination with synergistic effects to combat antibiotic-resistant E. anophelis and its associated biofilm. Methods E. anophelis isolates were identified by 16S rRNA sequencing; 30 strains with different pulsotypes were identified and the MIC, antibiotic resistance mechanism, antibiotic combination activity and killing effects of antimicrobial agents on biofilms of these strains were determined. Results All E. anophelis isolates were susceptible to minocycline and cefoperazone/sulbactam (1:1). More than 90% of clinical isolates were susceptible to cefoperazone/sulbactam (1:0.5), piperacillin/tazobactam and rifampicin. Some novel mutations, such as gyrA G81D, parE D585N and parC P134T, that have never been reported before, were identified. The synergistic effect was most prominent for the combination of minocycline and rifampicin, with 93.3% of their FIC index values ≤0.5, and no antagonism was observed using the chequerboard method. This synergistic effect between minocycline and rifampicin was also observed using time–killing methods for clinical E. anophelis isolates at both normal inoculum and high inoculum. Twenty-nine isolates tested positive for biofilm formation. Minocycline remained active against biofilm-embedded and biofilm-released planktonic E. anophelis cells; however, the enhanced effect of minocycline by adding rifampicin was only observed at 24 h (not at 72 and 120 h). Conclusions Although E. anophelis was resistant to many antibiotics and could exhibit biofilm formation, minocycline showed potent in vitro activity against this pathogen and its associated biofilm.

Download Full-text

In Vitro Activity of Vancapticin MCC5145 against Methicillin-Resistant Staphylococcus aureus from Periprosthetic Joint Infection

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02443-20 ◽

2021 ◽

Author(s):

Hye-Kyung Cho ◽

Melissa J. Karau ◽

Kerryl E. Greenwood-Quaintance ◽

Karl A. Hansford ◽

Matthew A. Cooper ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Periprosthetic Joint Infection ◽

Biofilm Formation ◽

Methicillin Resistant Staphylococcus Aureus ◽

Joint Infection ◽

Vitro Activity ◽

In Vitro Activity ◽

Methicillin Resistant

MRSA periprosthetic 1 joint infection (PJI) can be challenging to treat due to biofilm formation, alongside sometimes limited vancomycin activity (1-3).…

Download Full-text