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Battista S, Bellio P, Fagnani L, Allegritti E, Nazzicone L, Galantini L, Celenza G, Giansanti L. Structurally Related Liposomes Containing N-Oxide Surfactants: Physicochemical Properties and Evaluation of Antimicrobial Activity in Combination with Therapeutically Available Antibiotics. Mol Pharm 2022; 19:788-797. [PMID: 35170971 PMCID: PMC8905576 DOI: 10.1021/acs.molpharmaceut.1c00609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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Although liposomes
are largely investigated as drug delivery systems,
they can also exert a pharmacological activity if devoid of an active
principle as a function of their composition. Specifically, charged
liposomes can electrostatically interact with bacterial cells and,
in some cases, induce bacterial cell death. Moreover, they also show
a high affinity toward bacterial biofilms. We investigated the physicochemical
and antimicrobial properties of liposomes formulated with a natural
phospholipid and four synthetic l-prolinol-derived surfactants
at 9/1 and 8/2 molar ratios. The synthetic components differ in the
nature of the polar headgroup (quaternary ammonium salt or N-oxide) and/or the length of the alkyl chain (14 or 16
methylenes). These differences allowed us to investigate the effect
of the molecular structure of liposome components on the properties
of the aggregates and their ability to interact with bacterial cells.
The antimicrobial properties of the different formulations were assessed
against Gram-negative and Gram-positive bacteria and fungi. Drug–drug
interactions with four classes of available clinical antibiotics were
evaluated against Staphylococcus spp. The target
of each class of antibiotics plays a pivotal role in exerting a synergistic
effect. Our results highlight that the liposomal formulations with
an N-oxide moiety are required for the antibacterial
activity against Gram-positive bacteria. In particular, we observed
a synergism between oxacillin and liposomes containing 20 molar percentage
of N-oxide surfactants onStaphylococcus
haemolyticus, Staphylococcus epidermidis, andStaphylococcus aureus. In the
case of liposomes containing 20 molar percentage of the N-oxide surfactant with 14 carbon atoms in the alkyl chain for S. epidermidis, the minimum inhibitory concentration
was 0.125 μg/mL, well below the breakpoint value of the antibiotic.
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Affiliation(s)
- Sara Battista
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Via Vetoio 10, 67010 Coppito, AQ, Italy
| | - Pierangelo Bellio
- Dipartimento di Scienze Chimiche Applicate e Biotecnologie, Università degli Studi dell'Aquila, Via Vetoio 10, 67010 Coppito, AQ, Italy
| | - Lorenza Fagnani
- Dipartimento di Scienze Chimiche Applicate e Biotecnologie, Università degli Studi dell'Aquila, Via Vetoio 10, 67010 Coppito, AQ, Italy
| | - Elena Allegritti
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Via Vetoio 10, 67010 Coppito, AQ, Italy
| | - Lisaurora Nazzicone
- Dipartimento di Scienze Chimiche Applicate e Biotecnologie, Università degli Studi dell'Aquila, Via Vetoio 10, 67010 Coppito, AQ, Italy
| | - Luciano Galantini
- Dipartimento di Chimica, Università degli Studi di Roma "Sapienza", P.le A. Moro 5, 00185 Roma, Italy
| | - Giuseppe Celenza
- Dipartimento di Scienze Chimiche Applicate e Biotecnologie, Università degli Studi dell'Aquila, Via Vetoio 10, 67010 Coppito, AQ, Italy
| | - Luisa Giansanti
- Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell'Aquila, Via Vetoio 10, 67010 Coppito, AQ, Italy
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Cyclic and Acyclic Amine Oxide Alkyl Derivatives as Potential Adjuvants in Antimicrobial Chemotherapy against Methicillin-Resistant Staphylococcus aureus with an MDR Profile. Antibiotics (Basel) 2021; 10:antibiotics10080952. [PMID: 34439002 PMCID: PMC8388947 DOI: 10.3390/antibiotics10080952] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/03/2021] [Accepted: 08/05/2021] [Indexed: 11/16/2022] Open
Abstract
The dramatic intensification of antimicrobial resistance occurrence in pathogenic bacteria concerns the global community. The revitalisation of inactive antibiotics is, at present, the only way to go through this health system crisis and the use of antimicrobial adjuvants is turning out the most promising approach. Due to their low toxicity, eco-friendly characteristics and antimicrobial activity, amphoteric surfactants are good candidates. This study investigated the adjuvant potentialities of commercial acyclic and newly cyclic N-oxide surfactants combined with therapeutically available antibiotics against MDR methicillin-resistant Staphylococcus aureus (MRSA). The safety profile of the new cyclic compounds, compared to commercial surfactants, was preliminarily assessed, evaluating the cytotoxicity on human peripheral mononuclear blood cells and the haemolysis in human red blood cells. The compounds show an efficacious antimicrobial activity strongly related to the length of the carbon atom chain. In drug–drug interaction assays, all surfactants act synergistically, restoring sensitivity to oxacillin in MRSA, with dodecyl acyclic and cyclic derivatives being the most effective. After evaluating the cytotoxicity and considering the antimicrobial action, the most promising compound is the L-prolinol amine-oxide C12NOX. These findings suggest that the combination of antibiotics with amphoteric surfactants is a valuable therapeutic option for topical infections sustained by multidrug-resistant S. aureus.
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