International Journal of Molecular Sciences

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12 pages, 3184 KiB

Open AccessArticle

Roles of DJ41_1407 and DJ41_1408 in Acinetobacter baumannii ATCC19606 Virulence and Antibiotic Response

by Yee-Huan Toh and Guang-Huey Lin

Int. J. Mol. Sci. 2024, 25(7), 3862; https://doi.org/10.3390/ijms25073862 - 29 Mar 2024

Viewed by 537

Abstract

Acinetobacter baumannii is a major cause of nosocomial infections, and its highly adaptive nature and broad range of antibiotic resistance enable it to persist in hospital environments. A. baumannii often employs two-component systems (TCSs) to regulate adaptive responses and virulence-related traits. This study [...] Read more.

Acinetobacter baumannii is a major cause of nosocomial infections, and its highly adaptive nature and broad range of antibiotic resistance enable it to persist in hospital environments. A. baumannii often employs two-component systems (TCSs) to regulate adaptive responses and virulence-related traits. This study describes a previously uncharacterized TCS in the A. baumannii ATCC19606 strain, consisting of a transcriptional sensor, DJ41_1407, and its regulator, DJ41_1408, located adjacent to GacA of the GacSA TCS. Markerless mutagenesis was performed to construct DJ41_1407 and DJ41_1408 single and double mutants. DJ41_1408 was found to upregulate 49 genes and downregulate 43 genes, most of which were associated with carbon metabolism and other metabolic pathways, such as benzoate degradation. MEME analysis revealed a putative binding box for DJ41_1408, 5′TGTAAATRATTAYCAWTWAT3′. Colony size, motility, biofilm-forming ability, virulence, and antibiotic resistance of DJ41_1407 and DJ41_1408 single and double mutant strains were assessed against wild type. DJ41_1407 was found to enhance motility, while DJ41_1408 was found to upregulate biofilm-forming ability, and may also modulate antibiotic response. Both DJ41_1407 and DJ41_1408 suppressed virulence, based on results from a G. mellonella infection assay. These results showcase a novel A. baumannii TCS involved in metabolism, with effects on motility, biofilm-forming ability, virulence, and antibiotic response. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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19 pages, 4987 KiB

Open AccessArticle

The Effect of Ficin Immobilized on Carboxymethyl Chitosan on Biofilms of Oral Pathogens

by Diana R. Baidamshina, Elena Yu. Trizna, Svetlana S. Goncharova, Andrey V. Sorokin, Maria S. Lavlinskaya, Anastasia P. Melnik, Leysan F. Gafarova, Maya A. Kharitonova, Olga V. Ostolopovskaya, Valeriy G. Artyukhov, Evgenia A. Sokolova, Marina G. Holyavka, Mikhail I. Bogachev, Airat R. Kayumov and Pavel V. Zelenikhin

Int. J. Mol. Sci. 2023, 24(22), 16090; https://doi.org/10.3390/ijms242216090 - 8 Nov 2023

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Abstract

In the last decade, Ficin, a proteolytic enzyme extracted from the latex sap of the wild fig tree, has been widely investigated as a promising tool for the treatment of microbial biofilms, wound healing, and oral care. Here we report the antibiofilm properties [...] Read more.

In the last decade, Ficin, a proteolytic enzyme extracted from the latex sap of the wild fig tree, has been widely investigated as a promising tool for the treatment of microbial biofilms, wound healing, and oral care. Here we report the antibiofilm properties of the enzyme immobilized on soluble carboxymethyl chitosan (CMCh) and CMCh itself. Ficin was immobilized on CMCh with molecular weights of either 200, 350 or 600 kDa. Among them, the carrier with a molecular weight of 200 kDa bound the maximum amount of enzyme, binding up to 49% of the total protein compared to 19–32% of the total protein bound to other CMChs. Treatment with pure CMCh led to the destruction of biofilms formed by Streptococcus salivarius, Streptococcus gordonii, Streptococcus mutans, and Candida albicans, while no apparent effect on Staphylococcus aureus was observed. A soluble Ficin was less efficient in the destruction of the biofilms formed by Streptococcus sobrinus and S. gordonii. By contrast, treatment with CMCh200-immobilized Ficin led to a significant reduction of the biofilms of the primary colonizers S. gordonii and S. mutans. In model biofilms obtained by the inoculation of swabs from teeth of healthy volunteers, the destruction of the biofilm by both soluble and immobilized Ficin was observed, although the degree of the destruction varied between artificial plaque samples. Nevertheless, combined treatment of oral Streptococci biofilm by enzyme and chlorhexidine for 3 h led to a significant decrease in the viability of biofilm-embedded cells, compared to solely chlorhexidine application. This suggests that the use of either soluble or immobilized Ficin would allow decreasing the amount and/or concentration of the antiseptics required for oral care or improving the efficiency of oral cavity sanitization. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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17 pages, 5397 KiB

Open AccessArticle

The Association of Helicobacter pylori Biofilm with Enterovirus 71 Prolongs Viral Viability and Survival

by Ammar M. Hassanbhai, Meng Chee Phoon, Vincent T. Chow and Bow Ho

Int. J. Mol. Sci. 2023, 24(19), 14500; https://doi.org/10.3390/ijms241914500 - 24 Sep 2023

Viewed by 987

Abstract

The transition time during which a virus leaves its host and infects the next susceptible host is critical for virus survival. Enterovirus 71 (EV71) is stable in aqueous environments, but its molecular interactions with bacteria and their biofilms are not well-established. Helicobacter pylori [...] Read more.

The transition time during which a virus leaves its host and infects the next susceptible host is critical for virus survival. Enterovirus 71 (EV71) is stable in aqueous environments, but its molecular interactions with bacteria and their biofilms are not well-established. Helicobacter pylori is a highly successful gut bacterial pathogen, with its capacity to form biofilms being linked to its transmission. Given that both are gut-associated microbes, we hypothesized that biofilms formed by H. pylori may play a significant role in the survival of EV71 in the external environment. In this study, we examine the interactions of EV71 with the preformed biofilm of H. pylori to mimic its natural state in the environment. Immunofluorescence confocal microscopy and scanning electron microscopy revealed that EV71 particles persisted for up to 10 days when incubated with the H. pylori biofilm. Furthermore, the presence of the H. pylori biofilm significantly augmented viral viability, as verified through virus plaque assays. Interestingly, the viability of EV71 was dependent on the quantity of H. pylori biofilm formation. Thus, two H. pylori strains able to generate large amounts of biofilm could facilitate EV71 viability for up to 17 days, whereas two other H. pylori strains that produced moderate or low quantities of biofilm could not prolong virus viability. It is interesting that biofilm contains N-acetyl-glucosamine and glycosaminoglycan, and that EV71 has binding affinity to cell-surface heparan sulfate glycosaminoglycan, which acts as an EV71 attachment receptor. The synergistic ability of H. pylori biofilm to promote EV71 viability for extended periods implies that H. pylori biofilm may serve as an additional pathway of EV71 transmission. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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15 pages, 3350 KiB

Open AccessArticle

The Transcription Factor CsgD Contributes to Engineered Escherichia coli Resistance by Regulating Biofilm Formation and Stress Responses

by Cheng-Hai Yan, Fang-Hui Chen, Yu-Lu Yang, Yu-Fan Zhan, Richard A. Herman, Lu-Chan Gong, Sheng Sheng and Jun Wang

Int. J. Mol. Sci. 2023, 24(18), 13681; https://doi.org/10.3390/ijms241813681 - 5 Sep 2023

Cited by 2 | Viewed by 1289

Abstract

The high cell density, immobilization and stability of biofilms are ideal characteristics for bacteria in resisting antibiotic therapy. CsgD is a transcription activating factor that regulates the synthesis of curly fimbriae and cellulose in Escherichia coli, thereby enhancing bacterial adhesion and promoting [...] Read more.

The high cell density, immobilization and stability of biofilms are ideal characteristics for bacteria in resisting antibiotic therapy. CsgD is a transcription activating factor that regulates the synthesis of curly fimbriae and cellulose in Escherichia coli, thereby enhancing bacterial adhesion and promoting biofilm formation. To investigate the role of CsgD in biofilm formation and stress resistance in bacteria, the csgD deletion mutant ΔcsgD was successfully constructed from the engineered strain E. coli BL21(DE3) using the CRISPR/Cas9 gene-editing system. The results demonstrated that the biofilm of ΔcsgD decreased by 70.07% (p < 0.05). Additionally, the mobility and adhesion of ΔcsgD were inhibited due to the decrease in curly fimbriae and extracellular polymeric substances. Furthermore, ΔcsgD exhibited a significantly decreased resistance to acid, alkali and osmotic stress conditions (p < 0.05). RNA-Seq results revealed 491 differentially expressed genes between the parent strain and ΔcsgD, with enrichment primarily observed in metabolism-related processes as well as cell membrane structure and catalytic activity categories. Moreover, CsgD influenced the expression of biofilm and stress response genes pgaA, motB, fimA, fimC, iraP, ompA, osmC, sufE and elaB, indicating that the CsgD participated in the resistance of E. coli by regulating the expression of biofilm and stress response. In brief, the transcription factor CsgD plays a key role in the stress resistance of E. coli, and is a potential target for treating and controlling biofilm. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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16 pages, 2627 KiB

Open AccessArticle

Simultaneous Irradiation with UV-A, -B, and -C Lights Promotes Effective Decontamination of Planktonic and Sessile Bacteria: A Pilot Study

by Andrea Bosso, Francesca Tortora, Rosanna Culurciello, Ilaria Di Nardo, Valeria Pistorio, Federica Carraturo, Andrea Colecchia, Rocco Di Girolamo, Valeria Cafaro, Eugenio Notomista, Raffaele Ingenito and Elio Pizzo

Int. J. Mol. Sci. 2023, 24(16), 12951; https://doi.org/10.3390/ijms241612951 - 18 Aug 2023

Cited by 1 | Viewed by 891

Abstract

Surfaces in highly anthropized environments are frequently contaminated by both harmless and pathogenic bacteria. Accidental contact between these contaminated surfaces and people could contribute to uncontrolled or even dangerous microbial diffusion. Among all possible solutions useful to achieve effective disinfection, ultraviolet irradiations (UV) [...] Read more.

Surfaces in highly anthropized environments are frequently contaminated by both harmless and pathogenic bacteria. Accidental contact between these contaminated surfaces and people could contribute to uncontrolled or even dangerous microbial diffusion. Among all possible solutions useful to achieve effective disinfection, ultraviolet irradiations (UV) emerge as one of the most “Green” technologies since they can inactivate microorganisms via the formation of DNA/RNA dimers, avoiding the environmental pollution associated with the use of chemical sanitizers. To date, mainly UV-C irradiation has been used for decontamination purposes, but in this study, we investigated the cytotoxic potential on contaminated surfaces of combined UV radiations spanning the UV-A, UV-B, and UV-C spectrums, obtained with an innovative UV lamp never conceived so far by analyzing its effect on a large panel of collection and environmental strains, further examining any possible adverse effects on eukaryotic cells. We found that this novel device shows a significant efficacy on different planktonic and sessile bacteria, and, in addition, it is compatible with eukaryotic skin cells for short exposure times. The collected data strongly suggest this new lamp as a useful device for fast and routine decontamination of different environments to ensure appropriate sterilization procedures. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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17 pages, 4558 KiB

Open AccessArticle

Antibiofilm Activity and Mechanism of Linalool against Food Spoilage Bacillus amyloliquefaciens

by Guanghui Shen, Lu Yang, Xinyu Lv, Yingfan Zhang, Xiaoyan Hou, Meiliang Li, Man Zhou, Le Pan, Anjun Chen and Zhiqing Zhang

Int. J. Mol. Sci. 2023, 24(13), 10980; https://doi.org/10.3390/ijms241310980 - 1 Jul 2023

Cited by 2 | Viewed by 1465

Abstract

Pellicle biofilm-forming bacteria Bacillus amyloliquefaciens are the major spoilage microorganisms of soy products. Due to their inherent resistance to antibiotics and disinfectants, pellicle biofilms formed are difficult to eliminate and represent a threat to food safety. Here, we assessed linalool’s ability to prevent [...] Read more.

Pellicle biofilm-forming bacteria Bacillus amyloliquefaciens are the major spoilage microorganisms of soy products. Due to their inherent resistance to antibiotics and disinfectants, pellicle biofilms formed are difficult to eliminate and represent a threat to food safety. Here, we assessed linalool’s ability to prevent the pellicle of two spoilage B. amyloliquefaciens strains. The minimum biofilm inhibitory concentration (MBIC) of linalool against B. amyloliquefaciens DY1a and DY1b was 4 μL/mL and 8 μL/mL, respectively. The MBIC of linalool had a considerable eradication rate of 77.15% and 83.21% on the biofilm of the two strains, respectively. Scanning electron microscopy observations revealed that less wrinkly and thinner pellicle biofilms formed on a medium supplemented with 1/2 MBIC and 1/4 MBIC linalool. Also, linalool inhibited cell motility and the production of extracellular polysaccharides and proteins of the biofilm matrix. Furthermore, linalool exposure reduced the cell surface hydrophobicity, zeta potential, and cell auto-aggregation of B. amyloliquefaciens. Molecular docking analysis demonstrated that linalool interacted strongly with quorum-sensing ComP receptor and biofilm matrix assembly TasA through intermolecular hydrogen bonds, hydrophobic contacts, and van der Waals forces interacting with site residues. Overall, our findings suggest that linalool may be employed as a potential antibiofilm agent to control food spoilage B. amyloliquefaciens. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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16 pages, 5738 KiB

Open AccessArticle

Isoespintanol Antifungal Activity Involves Mitochondrial Dysfunction, Inhibition of Biofilm Formation, and Damage to Cell Wall Integrity in Candida tropicalis

by Orfa Inés Contreras Martínez, Alberto Angulo Ortíz, Gilmar Santafé Patiño, Ana Peñata-Taborda and Ricardo Berrio Soto

Int. J. Mol. Sci. 2023, 24(12), 10187; https://doi.org/10.3390/ijms241210187 - 15 Jun 2023

Cited by 2 | Viewed by 1309

Abstract

The growing increase in infections caused by C. tropicalis, associated with its drug resistance and consequent high mortality, especially in immunosuppressed people, today generates a serious global public health problem. In the search for new potential drug candidates that can be used [...] Read more.

The growing increase in infections caused by C. tropicalis, associated with its drug resistance and consequent high mortality, especially in immunosuppressed people, today generates a serious global public health problem. In the search for new potential drug candidates that can be used as treatments or adjuvants in the control of infections by these pathogenic yeasts, the objective of this research was to evaluate the action of isoespintanol (ISO) against the formation of fungal biofilms, the mitochondrial membrane potential (ΔΨm), and its effect on the integrity of the cell wall. We report the ability of ISO to inhibit the formation of biofilms by up to 89.35%, in all cases higher than the values expressed by amphotericin B (AFB). Flow cytometric experiments using rhodamine 123 (Rh123) showed the ability of ISO to cause mitochondrial dysfunction in these cells. Likewise, experiments using calcofluor white (CFW) and analyzed by flow cytometry showed the ability of ISO to affect the integrity of the cell wall by stimulating chitin synthesis; these changes in the integrity of the wall were also observed through transmission electron microscopy (TEM). These mechanisms are involved in the antifungal action of this monoterpene. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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Review

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20 pages, 972 KiB

Open AccessReview

Bacterial Biofilm Formation on Biomaterials and Approaches to Its Treatment and Prevention

by Panxin Li, Rui Yin, Juanli Cheng and Jinshui Lin

Int. J. Mol. Sci. 2023, 24(14), 11680; https://doi.org/10.3390/ijms241411680 - 20 Jul 2023

Cited by 19 | Viewed by 5574

Abstract

Bacterial biofilms can cause widespread infection. In addition to causing urinary tract infections and pulmonary infections in patients with cystic fibrosis, biofilms can help microorganisms adhere to the surfaces of various medical devices, causing biofilm-associated infections on the surfaces of biomaterials such as [...] Read more.

Bacterial biofilms can cause widespread infection. In addition to causing urinary tract infections and pulmonary infections in patients with cystic fibrosis, biofilms can help microorganisms adhere to the surfaces of various medical devices, causing biofilm-associated infections on the surfaces of biomaterials such as venous ducts, joint prostheses, mechanical heart valves, and catheters. Biofilms provide a protective barrier for bacteria and provide resistance to antimicrobial agents, which increases the morbidity and mortality of patients. This review summarizes biofilm formation processes and resistance mechanisms, as well as the main features of clinically persistent infections caused by biofilms. Considering the various infections caused by clinical medical devices, we introduce two main methods to prevent and treat biomaterial-related biofilm infection: antibacterial coatings and the surface modification of biomaterials. Antibacterial coatings depend on the covalent immobilization of antimicrobial agents on the coating surface and drug release to prevent and combat infection, while the surface modification of biomaterials affects the adhesion behavior of cells on the surfaces of implants and the subsequent biofilm formation process by altering the physical and chemical properties of the implant material surface. The advantages of each strategy in terms of their antibacterial effect, biocompatibility, limitations, and application prospects are analyzed, providing ideas and research directions for the development of novel biofilm infection strategies related to therapeutic materials. Full article

(This article belongs to the Special Issue Biofilm Antimicrobial Strategies: Outlook and Future Perspectives)

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