Exploring the Effect of the Composition of Three Different Oregano Essential Oils on the Growth of Multidrug-Resistant Cystic Fibrosis Pseudomonas aeruginosa Strains

Oregano essential oils (EOs) could represent interesting therapeutic strategies to treat multidrug-resistant (MDR) pathogens as Pseudomonas aeruginosa, responsible for respiratory infections in cystic fibrosis (CF) patients. There could be a great variability in EOs composition when extracted from different plant species. The aim of this study was to chemically characterize and to test EOs, extracted from Origanum compactum, Origanum vulgare and Origanum vulgare var. hirtum, for in vitro antimicrobial activity against a panel of twenty MDR P. aeruginosa strains isolated from CF patients. EOs main components were carvacrol (71.8-73.8-47.1%), thymol (1.6-2.3-21.5%), p-cymene (11.6-7.4-10.8%) and γ-terpinene (1.7-3.1-8.4%). In general, the EOs showed inhibitory activity even at low concentration: 0.5% (v/v) OvEO and OhEO were able to inhibit the 80% of P. aeruginosa strains. Furthermore, the three EOs killed at least 75% of the strains at concentrations lower than 1% (v/v). Average MIC and MBC values were not significantly different. Similar levels of OEOs antimicrobial activities might be related to the fact that the main chemical class (i.e. carvacrol/thymol) is represented in quite similar percentages. Hence, the results of the present study shed light on a carvacrol/thymol-rich EO with a well-represented monoterpene hydrocarbons class as promising standardized antimicrobial herbal product.

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In Vitro Newly Isolated Environmental Phage Activity against Biofilms Preformed by Pseudomonas aeruginosa from Patients with Cystic Fibrosis

Microorganisms ◽

10.3390/microorganisms9030478 ◽

2021 ◽

Vol 9 (3) ◽

pp. 478

Author(s):

Ersilia Vita Fiscarelli ◽

Martina Rossitto ◽

Paola Rosati ◽

Nour Essa ◽

Valentina Crocetta ◽

...

Keyword(s):

Cystic Fibrosis ◽

Pseudomonas Aeruginosa ◽

Multidrug Resistant ◽

In Vitro Test ◽

Chronic Infections ◽

Hospital Environments ◽

Vitro Test ◽

General Reliability ◽

Phage Activity

As disease worsens in patients with cystic fibrosis (CF), Pseudomonas aeruginosa (PA) colonizes the lungs, causing pulmonary failure and mortality. Progressively, PA forms typical biofilms, and antibiotic treatments determine multidrug-resistant (MDR) PA strains. To advance new therapies against MDR PA, research has reappraised bacteriophages (phages), viruses naturally infecting bacteria. Because few in vitro studies have tested phages on CF PA biofilms, general reliability remains unclear. This study aimed to test in vitro newly isolated environmental phage activity against PA isolates from patients with CF at Bambino Gesù Children’s Hospital (OBG), Rome, Italy. After testing in vitro phage activities, we combined phages with amikacin, meropenem, and tobramycin against CF PA pre-formed biofilms. We also investigated new emerging morphotypes and bacterial regrowth. We obtained 22 newly isolated phages from various environments, including OBG. In about 94% of 32 CF PA isolates tested, these phages showed in vitro PA lysis. Despite poor efficacy against chronic CF PA, five selected-lytic-phages (Φ4_ZP1, Φ9_ZP2, Φ14_OBG, Φ17_OBG, and Φ19_OBG) showed wide host activity. The Φ4_ZP1-meropenem and Φ14_OBG-tobramycin combinations significantly reduced CF PA biofilms (p < 0.001). To advance potential combined phage-antibiotic therapy, we envisage further in vitro test combinations with newly isolated phages, including those from hospital environments, against CF PA biofilms from early and chronic infections.

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Essential Oil from Origanum vulgare Completely Inhibits the Growth of Multidrug-Resistant Cystic Fibrosis Pathogens

Natural Product Communications ◽

10.1177/1934578x1601100641 ◽

2016 ◽

Vol 11 (6) ◽

pp. 1934578X1601100 ◽

Cited By ~ 4

Author(s):

Giovanna Pesavento ◽

Valentina Maggini ◽

Isabel Maida ◽

Antonella Lo Nostro ◽

Carmela Calonico ◽

...

Keyword(s):

Cystic Fibrosis ◽

Essential Oil ◽

Multidrug Resistant ◽

Diffusion Method ◽

Achromobacter Xylosoxidans ◽

Bacterial Strains ◽

Origanum Vulgare ◽

Disk Diffusion Method ◽

Wide Range

Essential oils (EOs) are known to inhibit the growth of a wide range of microorganisms. Particularly interesting is the possible use of EOs to treat multidrug-resistant cystic fibrosis (CF) pathogens. We tested the essential oil (EO) from Origanum vulgare for in vitro antimicrobial activity, against three of the major human opportunistic pathogens responsible for respiratory infections in CF patients; these are methicillin-resistant Staphylococcus aureus, Stenotrophomonas maltophilia and Achromobacter xylosoxidans. Antibiotic susceptibility of each strain was previously tested by the standard disk diffusion method. Most strains were resistant to multiple antibiotics and could be defined as multi-drug-resistant (MDR). The antibacterial activity of O. vulgare EO (OEO) against a panel of 59 bacterial strains was evaluated, with MIC and MBC determined at 24, 48 and 72 hours by a microdilution method. The OEO was effective against all tested strains, although to a different extent. The MBC and MIC of OEO for S. aureus strains were either lower or equal to 0.50%, v/v, for A. xylosoxidans strains were lower or equal to 1% and 0.50%, v/v, respectively; and for S. maltophilia strains were lower or equal to 0.25%, v/v. The results from this study suggest that OEO might exert a role as an antimicrobial in the treatment of CF infections.

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Poly (acetyl arginyl) glucosamine attenuates Pseudomonas aeruginosa in a rat lung infection model

10.1101/2021.09.15.460521 ◽

2021 ◽

Author(s):

Bryan Garcia ◽

Melissa S. McDaniel ◽

Allister J. Loughran ◽

J. Dixon Johns ◽

Vidya Narayanaswamy ◽

...

Keyword(s):

Cystic Fibrosis ◽

Pseudomonas Aeruginosa ◽

Respiratory Infections ◽

Bacterial Species ◽

Membrane Integrity ◽

Opportunistic Pathogen ◽

Infection Model ◽

Total Biomass ◽

Chronic Infections

Pseudomonas aeruginosa is a common opportunistic pathogen that can cause chronic infections in multiple disease states, including respiratory infections in patients with cystic fibrosis (CF) and non-CF bronchiectasis. Like many opportunists, P. aeruginosa forms multicellular biofilm communities that are widely thought to be an important determinant of bacterial persistence and resistance to antimicrobials and host immune effectors during chronic/recurrent infections. Poly (acetyl, arginyl) glucosamine (PAAG) is a glycopolymer which has antimicrobial activity against a broad range of bacterial species, and also has mucolytic activity which can normalize rheologic properties of cystic fibrosis mucus. In this study, we sought to evaluate the effect of PAAG on P. aeruginosa bacteria within biofilms in vitro, and in the context of experimental pulmonary infection in a rodent infection model. PAAG treatment caused significant bactericidal activity against P. aeruginosa biofilms, and a reduction in the total biomass of preformed P. aeruginosa biofilms on abiotic surfaces, as well as on the surface of immortalized cystic fibrosis human bronchial epithelial cells. Studies of membrane integrity indicated that PAAG causes changes to P. aeruginosa cell morphology and dysregulates membrane polarity. PAAG treatment reduced infection and consequent tissue inflammation in experimental P. aeruginosa rat infections. Based on these findings we conclude that PAAG represents a novel means to combat P. aeruginosa infection, which may warrant further evaluation as a therapeutic.

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Chitosan-Stabilized Ag Nanoparticles with Superior Biocompatibility and Their Synergistic Antibacterial Effect in Mixtures with Essential Oils

Nanomaterials ◽

10.3390/nano8100826 ◽

2018 ◽

Vol 8 (10) ◽

pp. 826 ◽

Cited By ~ 20

Author(s):

Ludmila Cinteza ◽

Cristina Scomoroscenco ◽

Sorina Voicu ◽

Cristina Nistor ◽

Sabina Nitu ◽

...

Keyword(s):

Antibacterial Activity ◽

Essential Oils ◽

Metallic Nanoparticles ◽

Synergistic Effects ◽

Medical Application ◽

Colloidal Dispersion ◽

Multidrug Resistant ◽

Antimicrobial Activities ◽

Promising Alternative

Silver nanoparticles (AgNPs) are considered a promising alternative to the use of antibiotics in fighting multidrug-resistant pathogens. However, their use in medical application is hindered by the public concern regarding the toxicity of metallic nanoparticles. In this study, rationally designed AgNP were produced, in order to balance the antibacterial activity and toxicity. A facile, environmentally friendly synthesis was used for the electrochemical fabrication of AgNPs. Chitosan was employed as the capping agent, both for the stabilization and to improve the biocompatibility. Size, morphology, composition, capping layer, and stability of the synthesized nanoparticles were characterized. The in vitro biocompatibility and antimicrobial activities of AgNPs against common Gram-negative and Gram-positive bacteria were evaluated. The results revealed that chitosan-stabilized AgNPs were nontoxic to normal fibroblasts, even at high concentrations, compared to bare nanoparticles, while significant antibacterial activity was recorded. The silver colloidal dispersion was further mixed with essential oils (EO) to increase the biological activity. Synergistic effects at some AgNP–EO ratios were observed, as demonstrated by the fractionary inhibitory concentration values. Our results reveal that the synergistic action of both polymer-stabilized AgNPs and essential oils could provide a significant efficiency against a large variety of microorganisms, with minimal side effects.

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Antimicrobial activity of essential oils extracted from leaves of native Moroccan plants against clinical bacterial isolates

The International Arabic Journal of Antimicrobial Agents ◽

10.3823/819 ◽

2018 ◽

Vol 8 (1) ◽

Author(s):

Fatima El Malki ◽

Kamal Eddaraji ◽

Rajae Alloudane ◽

Hassane Greche ◽

Haiat Essalmani ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Antimicrobial Activity ◽

Antibacterial Activity ◽

Essential Oils ◽

Bactericidal Effect ◽

Antimicrobial Activities ◽

Acinetobacter Baumanii ◽

And Staphylococcus Aureus

Introduction: Medicinal plants are plentiful of bioactive molecules effective against multi-resistance bacteria. The aims of this study were to assess the in vitro antimicrobial activities of essential oils extracted from three Moroccan aromatic plants. Methodology: Analysis of essential oils of Origanum compactum, Rosmarinus officinalis and Pelargonium asperum, collected from different localities in Morocco, were performed using a GC-MS spectrophotometry. Antibacterial activity was evaluated in vitro for five clinical multi-resistant isolates. Results: Origanum showed strong antibacterial activity against tested strains except Pseudomonas aeruginosa while Rosmarinum showed a bactericidal effect against Acinetobacter baumanii, Escherichia coli and Staphylococcus aureus. Pelargonium presented only slight growth inhibition of Staphylococcus aureus on solid medium, but provided bactericidal effect against Acinetobacter baumanii and Staphylococcus aureus. Interestingly, fractions F7 and F8 of Pelargonium which represented only 0.3% and 0.1% of the total mass were found bactericidal respectively against Klebsiella pneumoniae and Pseudomonas aeruginosa. Conclusions: Ours results showed that the antimicrobial activities were variables depending on the chemical composition of essential oils, the fraction used and the microorganism tested.Essential oils fractionation allows detection of bioactive substances, especially those owning antimicrobial activity, present in small quantities.

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1594. Ceftolozane–Tazobactam Demonstrates Higher In Vitro Susceptibility than Ceftazidime–Avibactam Against Pseudomonas aeruginosa Isolated from Respiratory Tract of Adult Cystic Fibrosis Patients

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1458 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S581-S582

Author(s):

Patrick James Nolan ◽

Tiffeny Smith ◽

James D Finklea ◽

Leah Cohen ◽

Raksha Jain

Keyword(s):

Cystic Fibrosis ◽

Pseudomonas Aeruginosa ◽

Susceptibility Testing ◽

Clinical Laboratory ◽

Multidrug Resistant ◽

Vitro Activity ◽

Drug Resistant ◽

In Vitro Activity ◽

In Vitro Susceptibility

Abstract Background Pseudomonas aeruginosa is a commonly isolated pathogen in adults with cystic fibrosis (CF). Antimicrobial resistance is an escalating problem due to chronic colonization and frequent antimicrobial exposure. Ceftolozane–tazobactam (C/T) and ceftazidime–avibactam (CZA) exhibit promising activity against antimicrobial-resistant organisms, including P. aeruginosa. In this study, we compared in vitro activity of C/T and CZA against P. aeruginosa isolated from respiratory cultures obtained from adult patients with CF. Methods This is a retrospective study of respiratory cultures positive for P. aeruginosa collected from adult CF patients between January 1, 2015 to November 30, 2018. The first isolate per patient per year that underwent susceptibility testing for C/T, CZA, and colistin were included in the study. All isolates underwent in-house susceptibility testing for 9 anti-pseudomonal agents according to the methodology established by the Clinical Laboratory Standards Institute (CLSI). Susceptibility testing of C/T, CZA, and colistin were performed by a reference lab. Isolates were classified into 3 drug-resistant categories using the following definition: multidrug-resistant (MDR) non-susceptible (NS) to ≥1 agent in ≥3 different antimicrobial classes, extensive drug-resistant (XDR) NS to 4 or 5 different classes, and pan drug-resistant (PDR) NS to all 6 classes except colistin. Results Forty-two P. aeruginosa respiratory isolates from 32 patients with CF were included. The overall susceptibility to C/T and CZA was 59.5% and 42.9%, respectively. Thirty-eight (90%) isolates were considered MDR with susceptibility of 55.3% to C/T and 44.7% to CZA. Among the 11 XDR isolates, susceptibility to C/T was 81.8% vs. CZA 72.7%. Susceptibility to C/T vs. CZA was also higher (37.5% vs. 25%) among the 24 PDR isolates. Conclusion Among P. aeruginosa isolated from CF respiratory cultures, C/T appears to have better in vitro activity compared with CZA, and remained true among isolates considered XDR and PDR. These results suggest using C/T while awaiting susceptibilities when standard anti-pseudomonal agents cannot be used. Future studies evaluating clinical outcomes for the treatment of pulmonary CF exacerbations are needed to assess the applicability of in vitro susceptibility data. Disclosures All authors: No reported disclosures.

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In Vitro Activity of Ceftolozane-Tazobactam against Multidrug-Resistant Nonfermenting Gram-Negative Bacilli Isolated from Patients with Cystic Fibrosis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02688-16 ◽

2017 ◽

Vol 61 (4) ◽

Cited By ~ 11

Author(s):

Patrick Grohs ◽

Gary Taieb ◽

Philippe Morand ◽

Iheb Kaibi ◽

Isabelle Podglajen ◽

...

Keyword(s):

Cystic Fibrosis ◽

Pseudomonas Aeruginosa ◽

Stenotrophomonas Maltophilia ◽

Active Agent ◽

Multidrug Resistant ◽

In Vitro Activity ◽

Gram Negative ◽

Content Type ◽

Time Kill

ABSTRACT Ceftolozane-tazobactam was tested against 58 multidrug-resistant nonfermenting Gram-negative bacilli (35 Pseudomonas aeruginosa, 11 Achromobacter xylosoxydans, and 12 Stenotrophomonas maltophilia isolates) isolated from cystic fibrosis patients and was compared to ceftolozane alone, ceftazidime, meropenem, and piperacillin-tazobactam. Ceftolozane-tazobactam was the most active agent against P. aeruginosa but was inactive against A. xylosoxydans and S. maltophilia. In time-kill experiments, ceftolozane-tazobactam had complete bactericidal activity against 2/6 clinical isolates (33%).

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Clinically Relevant Concentrations of Polymyxin B and Meropenem Synergistically Kill Multidrug-Resistant Pseudomonas aeruginosa and Minimize Biofilm Formation

Antibiotics ◽

10.3390/antibiotics10040405 ◽

2021 ◽

Vol 10 (4) ◽

pp. 405

Author(s):

Hasini Wickremasinghe ◽

Heidi H. Yu ◽

Mohammad A. K. Azad ◽

Jinxin Zhao ◽

Phillip J. Bergen ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Respiratory Infections ◽

Population Analysis ◽

Membrane Damage ◽

Membrane Integrity ◽

Polymyxin B ◽

Multidrug Resistant ◽

Bacterial Killing

The emergence of antibiotic resistance has severely impaired the treatment of chronic respiratory infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa. Since the reintroduction of polymyxins as a last-line therapy against MDR Gram-negative bacteria, resistance to its monotherapy and recurrent infections continue to be reported and synergistic antibiotic combinations have been investigated. In this study, comprehensive in vitro microbiological evaluations including synergy panel screening, population analysis profiling, time-kill kinetics, anti-biofilm formation and membrane damage analysis studies were conducted to evaluate the combination of polymyxin B and meropenem against biofilm-producing, polymyxin-resistant MDR P. aeruginosa. Two phylogenetically unrelated MDR P. aeruginosa strains, FADDI-PA060 (MIC of polymyxin B [MICpolymyxin B], 64 mg/L; MICmeropenem, 64 mg/L) and FADDI-PA107 (MICpolymyxin B, 32 mg/L; MICmeropenem, 4 mg/L) were investigated. Genome sequencing identified 57 (FADDI-PA060) and 50 (FADDI-PA107) genes predicted to confer resistance to a variety of antimicrobials, as well as multiple virulence factors in each strain. The presence of resistance genes to a particular antibiotic class generally aligned with MIC results. For both strains, all monotherapies of polymyxin B failed with substantial regrowth and biofilm formation. The combination of polymyxin B (16 mg/L)/meropenem (16 mg/L) was most effective, enhancing initial bacterial killing of FADDI-PA060 by ~3 log10 CFU/mL, followed by a prolonged inhibition of regrowth for up to 24 h with a significant reduction in biofilm formation (* p < 0.05). Membrane integrity studies revealed a substantial increase in membrane depolarization and membrane permeability in the surviving cells. Against FADDI-PA107, planktonic and biofilm bacteria were completely eradicated. In summary, the combination of polymyxin B and meropenem demonstrated synergistic bacterial killing while reinstating the efficacy of two previously ineffective antibiotics against difficult-to-treat polymyxin-resistant MDR P. aeruginosa.

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