Evolution in the Lab: Biocide Resistance in E. coli

ACS Appl. Mater. Interfaces

et al. 2017

A number of oligo-p-phenylene-ethynylenes (OPEs) have exhibited excellent biocidal activity against both Gram-negative and Gram-positive bacteria. Although cell death may occur in the dark, these biocidal compounds are far more effective in the light as a result of their abilities to generate cell-damaging reactive oxygen species. In this study, the interactions of four OPEs with Escherichia coli and Staphylococcus aureus have been investigated. Compared to the OPEs with quaternary ammonium salts (Q-OPE), the OPEs with tertiary ammonium (T-OPE) effectively kill many more bacterial cells under light irradiation, presumably by severe perturbations of the bacterial cell wall and cytoplasmic membrane. According to the findings from this study, such intriguing light-induced antibacterial behavior is probably attributed to the combination of bacterial membrane disruption and the interfacial or intracellular generation of singlet oxygen or other ROS. Singlet oxygen was proved to be formed from irradiation of the OPEs, whereas the varying cell membrane perturbation abilities of OPEs enhance antibacterial activity.

Section: Introductionmentioning

confidence: 99%

Assessing the Biocidal Activity and Investigating the Mechanism of Oligo-p-phenylene-ethynylenes

Wang

ACS Appl. Mater. Interfaces

et al. 2017

“…Diseases caused by bacterial infections have resulted in a large number of deaths and have become one of the most severe threats to human health. − The research and development of antibiotics has changed this situation and has saved a lot of people. However, drug resistance accompanying the wide use of antibiotics brings new challenges and demands alternative approaches to treat bacterial contamination. − Among these approaches, photodynamic therapy (PDT) has attracted much research interest owing to some advantages, including broad-spectrum antibacterial activity and low drug resistance. − The mechanism of PDT has been well documented, and the light-induced reactive oxygen species (ROS) is critical for PDT. − Recently, the antibacterial activities of cationic (poly) phenylene ethynylene (PPE), oligo-phenylene ethynylene (OPE), and polythiophenes (PTP) have attracted much research interest. − These materials could kill Gram-positive and Gram-negative bacteria once they are activated by near-ultraviolet (UV) or visible light, and antibacterial activity under dark conditions can also be observed for some kinds of materials.…”

Section: Introductionmentioning

confidence: 99%

Comparison and Mechanism Study of Antibacterial Activity of Cationic and Neutral Oligo-Thiophene-Ethynylene

Shi

ACS Appl. Mater. Interfaces

et al. 2021

Photodynamic therapy (PDT) is a potential approach to resolve antibiotic resistance, and phenylene/thiophene-ethynylene oligomers have been widely studied as effective antibacterial reagents. Oligomers with thiophene moieties usually exhibit good antibacterial activity under light irradiation and dark conditions. In the previous study, we verified that neutral oligo-p-phenylene-ethynylenes (OPEs) exhibit better antibacterial activity than the corresponding cationic ones; however, whether this regular pattern also operates in other kinds of oligomers such as oligo-thiophene-ethynylene (OTE) is unknown. Also, the antibacterial activity comparison of OTEs bearing cyclic and acyclic amino groups will offer useful information to further understand the role of amino groups in the antibacterial process and guide the antibacterial reagent design as amino groups affect the antibacterial activity a lot. We synthesized four OTEs bearing neutral or cationic, cyclic, or acyclic amino groups and studied their antibacterial activity in detail. The experimental results indicated that the OTEs exhibited better antibacterial activity than the OPEs, the neutral OTEs exhibited better antibacterial activity in most cases, and OTEs bearing cyclic amino groups exhibited better antibacterial activity than those bearing acyclic ones in most cases. This study provides useful guidelines for further antibacterial reagent design and investigations.

“…A healthcare-associated infection (HAI) is acquired by patients while receiving care and represents the most frequent adverse event and results in tens of thousands of death per year only in the US. HAI has added enormous social burden to the world . Adding that the emergence of superbugs that have developed high levels of resistance to major clinical antibiotics used in the treatment for pathogenic infections makes this problem even worse. − There is an urgent need to develop alternative and effective strategies to treat infections, especially the infections caused by Staphylococcus aureus , which is responsible for ∼50% of multidrug-resistant infection cases clinically. , Among the approaches, light-induced inactivation of pathogens is a promising strategy.…”

Section: Introductionmentioning

confidence: 99%

“…HAI has added enormous social burden to the world. 1 Adding that the emergence of superbugs that have developed high levels of resistance to major clinical antibiotics used in the treatment for pathogenic infections makes this problem even worse. 2−4 There is an urgent need to develop alternative and effective strategies to treat infections, especially the infections caused by Staphylococcus aureus, which is responsible for ∼50% of multidrug-resistant infection cases clinically.…”

Section: ■ Introductionmentioning

confidence: 99%

“…5,6 Among the approaches, light-induced inactivation of pathogens is a promising strategy. The photoinactivation reaction has been well documented, and the process is believed to involve three steps: (1) A photosensitizer is excited from the ground state S0 to its excited singlet state S1; (2) S1 decays to a lower energy but longer-lived triplet state S3 via intersystem crossing (ISC) to result in efficient production of highly reactive oxygen species (ROS) or singlet oxygen ( 1 O 2 ) through an electron or energy transfer process; (3) ROS or 1 O 2 may further oxidize a variety of fundamental chemical constituents of cell walls and intracellular components, thereby compromising the proper functioning of the cell, and eventually, causing irreversible cellular damage and cell death. 7−12 The photosensitizers providing high-efficiency and broadspectrum antimicrobial activity play a key role in photoinactivation.…”

Section: ■ Introductionmentioning

confidence: 99%

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Biocidal Activity and Mechanism Study of Unsymmetrical Oligo-Phenylene-Ethynylenes

Xia

et al. 2020

ACS Appl. Bio Mater.

Bacterial contamination and the spread of antibiotic-resistant bacteria demand alternate methods to deal with bacterial infections. With particular advantages, photodynamic therapy (PDT) is a promising approach. As a kind of photosensitizer for PDT, light-induced antibacterial compounds like oligo-p-phenylene-ethynylenes (OPEs) have been widely investigated while these studies mainly focus on OPEs with quaternary ammonium salts. In our previous study, OPEs with tertiary amino groups (T-OPEs) were reported to exhibit a better antibacterial activity than the corresponding quaternary ammonium salts, which make it important to develop T-OPEs and further investigate their structure–activity relationship. Additionally, the terminal structure of the reported OPEs mainly consists of quaternary ammonium salts or tertiary amino groups, which could not be linked to other materials. Thus, to develop more effective and multifunctional antibacterial agents, we designed and synthesized four unsymmetrical OPEs having terminal amino groups, which could be linked to other functional units by covalent bonds. Their antibacterial activity against Gram-positive and Gram-negative bacteria and the mechanism have been investigated. The OPEs showed effective biocidal activity under fiber light irradiation, and no dark killing was observed. The mechanism study indicates that OPEs could penetrate and perturb the cell membrane and generate ROS under light irradiation, both of which could influence their antibacterial activity. The penetrating ability of OPEs is partly dependent on their lipophilicity and the structure and composition of the cell membrane.