The Search for Natural Inhibitors of Biofilm Formation and the Activity of the Autoinductor C6-AHL in Klebsiella pneumoniae ATCC 13884

Human nosocomial infections are common around the world. One of the main causes is the bacteria Klebsiella pneumoniae, which shows high rates of resistance to antibiotics. Thus, drugs with novel mechanisms of action are needed. In this work, we report the effects of various natural substances on the formation of biofilm in Klebsiella pneumoniae, as well as its stability. The effect of the molecules on the growth of K. pneumoniae was initially determined by measuring the optical density. The modification of the biofilm, the changes relating to its resistance, the effects on the bacterial adhesion to the urethral catheter and its antagonist role the hexanoyl-homoserinelactone were assessed by crystal violet, as well as by microscopy. The best effects were obtained with 3-methyl-2(5H)-furanone and 2´-hydroxycinnamic acid, which inhibited the formation of biofilm by 67.38% and 65.06%, respectively. Additionally, the remaining biofilm formed was more susceptible to gentamicin. Through microscopy examination, there were evident changes in the biofilm and adherence on the polyvinyl chloride (PVC) urethral catheter. Besides, 3-methyl-2(5H)-furanone inhibited the biofilm-forming effect of the autoinducer hexanoyl-homoserinelactone. Thus, these molecules could be developed as supplemental of antibiotics.

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Strategies for Antimicrobial Peptides Immobilization on Surfaces to Prevent Biofilm Growth on Biomedical Devices

Antibiotics ◽

10.3390/antibiotics11010013 ◽

2021 ◽

Vol 11 (1) ◽

pp. 13

Author(s):

Mathieu Nicolas ◽

Bruno Beito ◽

Marta Oliveira ◽

Maria Tudela Martins ◽

Bruno Gallas ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Surface Functionalization ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Biomedical Applications ◽

Mechanisms Of Action ◽

Bacterial Attachment ◽

Biofilm Growth ◽

Synthetic Routes ◽

Immobilization Techniques

Nosocomial and medical device-induced biofilm infections affect millions of lives and urgently require innovative preventive approaches. These pathologies have led to the development of numerous antimicrobial strategies, an emergent topic involving both natural and synthetic routes, among which some are currently under testing for clinical approval and use. Antimicrobial peptides (AMPs) are ideal candidates for this fight. Therefore, the strategies involving surface functionalization with AMPs to prevent bacterial attachment/biofilms formation have experienced a tremendous development over the last decade. In this review, we describe the different mechanisms of action by which AMPs prevent bacterial adhesion and/or biofilm formation to better address their potential as anti-infective agents. We additionally analyze AMP immobilization techniques on a variety of materials, with a focus on biomedical applications. Furthermore, we summarize the advances made to date regarding the immobilization strategies of AMPs on various surfaces and their ability to prevent the adhesion of various microorganisms. Progress toward the clinical approval of AMPs in antibiotherapy is also reviewed.

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Difference in biofilm formation between carbapenem-resistant and carbapenem-sensitive Klebsiella pneumoniae based on analysis of mrkH distribution

Microbial Pathogenesis ◽

10.1016/j.micpath.2021.104743 ◽

2021 ◽

Vol 152 ◽

pp. 104743

Author(s):

Renchi Fang ◽

Haiyang Liu ◽

Xiucai Zhang ◽

Guofeng Dong ◽

Jiahui Li ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Biofilm Formation ◽

Carbapenem Resistant

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Bond Strengthening in Oral Bacterial Adhesion to Salivary Conditioning Films

Applied and Environmental Microbiology ◽

10.1128/aem.01119-08 ◽

2008 ◽

Vol 74 (17) ◽

pp. 5511-5515 ◽

Cited By ~ 40

Author(s):

Henny C. van der Mei ◽

Minie Rustema-Abbing ◽

Joop de Vries ◽

Henk J. Busscher

Keyword(s):

Bacterial Adhesion ◽

Biofilm Formation ◽

Specific Interactions ◽

Adhesion Forces ◽

Bacterial Strains ◽

Bacterial Interactions ◽

Initial Adhesion ◽

Conditioning Film ◽

Interacting Surfaces ◽

Conditioning Films

ABSTRACT Transition from reversible to irreversible bacterial adhesion is a highly relevant but poorly understood step in initial biofilm formation. We hypothesize that in oral biofilm formation, irreversible adhesion is caused by bond strengthening due to specific bacterial interactions with salivary conditioning films. Here, we compared the initial adhesion of six oral bacterial strains to salivary conditioning films with their adhesion to a bovine serum albumin (BSA) coating and related their adhesion to the strengthening of the binding forces measured with bacteria-coated atomic force microscopy cantilevers. All strains adhered in higher numbers to salivary conditioning films than to BSA coatings, and specific bacterial interactions with salivary conditioning films were accompanied by stronger initial adhesion forces. Bond strengthening occurred on a time scale of several tens of seconds and was slower for actinomyces than for streptococci. Nonspecific interactions between bacteria and BSA coatings strengthened twofold faster than their specific interactions with salivary conditioning films, likely because specific interactions require a closer approach of interacting surfaces with the removal of interfacial water and a more extensive rearrangement of surface structures. After bond strengthening, bacterial adhesion forces with a salivary conditioning film remained stronger than those with BSA coatings.

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First report on the prevalence of Fasciola hepatica in the endangered Père David’s deer (Elaphurus davidianus) in China

BMC Veterinary Research ◽

10.1186/s12917-020-02694-9 ◽

2020 ◽

Vol 16 (1) ◽

Author(s):

Si-Yang Huang ◽

Jing-Zhi Gong ◽

Yi-Jun Ren ◽

Ming Pan ◽

Wei-Min Cai ◽

...

Keyword(s):

Fasciola Hepatica ◽

Potential Threat ◽

Prevalence Data ◽

First Report ◽

Natural Reserve ◽

Zoonotic Parasite ◽

The World ◽

Père David’S Deer ◽

Microscopy Examination ◽

Elaphurus Davidianus

Abstract Background Fasciola hepatica is an important zoonotic parasite that causes fasciolosis in a broad range of animals. No information is available about the prevalence of F. hepatica in Père David’s deer (Elaphurus davidianus), an endangered species in the world. Therefore, the purpose of the study was to evaluate the prevalence of fasciolosis in Père David’s deer in the Dafeng Elk National Natural Reserve, Jiangsu province, China. Results In this study, 142 fecal samples from Père David’s deer were analyzed for F. hepatica by microscopy and nest-PCR. Only one sample was positive for F. hepatica according to microscopy examination, while 18 of 142 (12.68, 95%CI: 2.841–22.45%) samples were positive for F. hepatica according to nest-PCR results. Conclusions This is the first report of prevalence of F. hepatica in Père David’s deer. The prevalence data indicated that F. hepatica was also present in this endangered animal, which may cause a potential threat to this precious species.

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A Real-Time Thermal Sensor System for Quantifying the Inhibitory Effect of Antimicrobial Peptides on Bacterial Adhesion and Biofilm Formation

Sensors ◽

10.3390/s21082771 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2771

Author(s):

Tobias Wieland ◽

Julia Assmann ◽

Astrid Bethe ◽

Christian Fidelak ◽

Helena Gmoser ◽

...

Keyword(s):

Antimicrobial Peptides ◽

Real Time ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Pathogenic Bacteria ◽

Bovine Mastitis ◽

Inhibitory Effect ◽

Thermal Sensor ◽

Bacterial Cells ◽

Static Conditions

The increasing rate of antimicrobial resistance (AMR) in pathogenic bacteria is a global threat to human and veterinary medicine. Beyond antibiotics, antimicrobial peptides (AMPs) might be an alternative to inhibit the growth of bacteria, including AMR pathogens, on different surfaces. Biofilm formation, which starts out as bacterial adhesion, poses additional challenges for antibiotics targeting bacterial cells. The objective of this study was to establish a real-time method for the monitoring of the inhibition of (a) bacterial adhesion to a defined substrate and (b) biofilm formation by AMPs using an innovative thermal sensor. We provide evidence that the thermal sensor enables continuous monitoring of the effect of two potent AMPs, protamine and OH-CATH-30, on surface colonization of bovine mastitis-associated Escherichia (E.) coli and Staphylococcus (S.) aureus. The bacteria were grown under static conditions on the surface of the sensor membrane, on which temperature oscillations generated by a heater structure were detected by an amorphous germanium thermistor. Bacterial adhesion, which was confirmed by white light interferometry, caused a detectable amplitude change and phase shift. To our knowledge, the thermal measurement system has never been used to assess the effect of AMPs on bacterial adhesion in real time before. The system could be used to screen and evaluate bacterial adhesion inhibition of both known and novel AMPs.

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The role of pgaC in Klebsiella pneumoniae virulence and biofilm formation

Microbial Pathogenesis ◽

10.1016/j.micpath.2014.11.005 ◽

2014 ◽

Vol 77 ◽

pp. 89-99 ◽

Cited By ~ 25

Author(s):

Kuang-Ming Chen ◽

Ming-Ko Chiang ◽

Meilin Wang ◽

Han-Chen Ho ◽

Min-Chi Lu ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Biofilm Formation

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Activity and Mechanism of Action of Antifungal Peptides from Microorganisms: A Review

Molecules ◽

10.3390/molecules26113438 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3438

Author(s):

Tianxi Li ◽

Lulu Li ◽

Fangyuan Du ◽

Lei Sun ◽

Jichao Shi ◽

...

Keyword(s):

Mechanisms Of Action ◽

Antifungal Drugs ◽

Drug Resistant ◽

Important Research ◽

Factors Affecting ◽

Natural Substances ◽

Therapeutic Drugs ◽

Antifungal Peptides ◽

Control Work ◽

And Control

Harmful fungi in nature not only cause diseases in plants, but also fungal infection and poisoning when people and animals eat food derived from crops contaminated with them. Unfortunately, such fungi are becoming increasingly more resistant to traditional synthetic antifungal drugs, which can make prevention and control work increasingly more difficult to achieve. This means they are potentially very harmful to human health and lifestyle. Antifungal peptides are natural substances produced by organisms to defend themselves against harmful fungi. As a result, they have become an important research object to help deal with harmful fungi and overcome their drug resistance. Moreover, they are expected to be developed into new therapeutic drugs against drug-resistant fungi in clinical application. This review focuses on antifungal peptides that have been isolated from bacteria, fungi, and other microorganisms to date. Their antifungal activity and factors affecting it are outlined in terms of their antibacterial spectra and effects. The toxic effects of the antifungal peptides and their common solutions are mentioned. The mechanisms of action of the antifungal peptides are described according to their action pathways. The work provides a useful reference for further clinical research and the development of safe antifungal drugs that have high efficiencies and broad application spectra.

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Bacterial adhesion to collagens: implications for biofilm formation and disease progression in the oral cavity

Critical Reviews in Microbiology ◽

10.1080/1040841x.2021.1944054 ◽

2021 ◽

pp. 1-13

Author(s):

Simón Álvarez ◽

Camila Leiva-Sabadini ◽

Christina M. A. P. Schuh ◽

Sebastian Aguayo

Keyword(s):

Oral Cavity ◽

Disease Progression ◽

Bacterial Adhesion ◽

Biofilm Formation

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Monolithic Ceramics: Effect of Finishing Techniques on Surface Properties, Bacterial Adhesion and Cell Viability

Operative Dentistry ◽

10.2341/17-011-l ◽

2018 ◽

Vol 43 (3) ◽

pp. 315-325 ◽

Cited By ~ 20

Author(s):

AMO Dal Piva ◽

LPC Contreras ◽

FC Ribeiro ◽

LC Anami ◽

SEA Camargo ◽

...

Keyword(s):

Mtt Assay ◽

Bacterial Adhesion ◽

Biofilm Formation ◽

Nonparametric Tests ◽

Lithium Silicate ◽

Gingival Fibroblasts ◽

Sem Images ◽

High Profile ◽

Colony Forming Units ◽

Monolithic Ceramics

SUMMARY Introduction: This study evaluated the morphology, biofilm formation, and viability of human gingival fibroblasts in contact with two monolithic ceramics after two different finishing techniques: polishing or glazing. For this, 92 blocks (4.5 × 4.5 × 1.5 mm) of each ceramic were made using high translucency zirconia partially stabilized by yttrium (YZHT) and lithium silicate reinforced by zirconium (ZLS). Methods and Materials: Blocks were sintered and then divided into glazing (g) or polishing (p) surface finish. Surface roughness (Ra and RSm) was evaluated through a contact rugosimeter and profilometry. Specimens were contaminated for heterotypic biofilm formation with Streptococcus mutans, Streptococcus sanguinis and Candida albicans for 16 hours. Biofilm was quantified by counting the colony forming units (CFU/mL) and analyzed by scanning electron microscopy (SEM). Fibroblast viability was evaluated by MTT assay. Surface free energy (SFE) was also determined. Roughness data were evaluated using nonparametric tests, while SFE, MTT and CFU results were evaluated by analysis of variance and Tukey test, and MTT data were also submitted to t-test (all, α=0.05). Results: Results showed that polished samples presented a lower high profile mean (p<0.001); however, YZHTg presented less space between defects (p=0.0002). SFE showed that YZHT presented higher SFE than ZLS. Profilometry evidenced more homogeneity on polished surfaces. The interaction of finishing technique and microorganisms influenced the CFU (p=0.00). MTT assay demonstrated initial severe cytotoxic behavior for polished surfaces. SEM images showed homogeneous surfaces, except for glazed YZHT. Conclusion: Glazed surfaces have a greater roughness and tend to accumulate more biofilm. Polished surfaces have higher SFE; however, they are temporarily cytotoxic.

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