Microbial biofilm, a consortium of microbial cells protected by a self-produced polymer matrix, is considered as one main cause of current bacterial drug resistance. As a new type of antimicrobial agents, antimicrobial peptides provide a new strategy for the treatment of antibiotic resistant bacteria biofilm infections. Antimicrobial peptides have shown unique advantages in preventing microbial colonization of surfaces, killing bacteria in biofilms or disrupting the mature biofilm structure. This review systemically analyzes published data in the recent 30 years to summarize the possible anti-biofilm mechanisms of antimicrobial peptides. We hope that this review can provide reference for the treatment of infectious diseases by pathogenic microbial biofilm.
Anti-Bacterial Agents ; pharmacology ; Antimicrobial Cationic Peptides ; pharmacology ; Bacteria ; drug effects ; Biofilms ; drug effects ; Drug Resistance, Bacterial ; drug effects ; Microbial Sensitivity Tests ; Research ; trends

This study aimed to investigate the effect of butyl alcohol extract of Baitouweng Decoction( BAEB) on Candida albicans biofilms based on pH signal pathway. The morphology of biofilms of the pH mutants was observed by scanning electron microscope. The biofilm thickness of the pH mutants was measured by CLSM. The biofilm activity of the pH mutants was analyzed by microplate reader.The biofilm damage of the pH mutants was detected by flow cytometry. The expression of pH mutant biofilm-related genes was detected by qRT-PCR. The results showed that the deletion of PHR1 gene resulted in the defect of biofilm,but there were more substrates for PHR1 complementation. BAEB had no significant effect on the two strains. RIM101 gene deletion or complementation did not cause significant structural damage,but after BAEB treatment,the biofilms of both strains were significantly inhibited. For the biofilm thickness,PHR1 deletion or complementation caused the thickness to decrease,after BAEB treatment,the thickness of the two strains did not change significantly. However,RIM101 gene deletion or complementation had little effect on the thickness,and the thickness of the two strains became thinner after adding BAEB. For biofilm activity,PHR1 deletion or complementation and RIM101 deletion resulted in decreased activity,RIM101 complementation did not change significantly; BAEB significantly inhibited biofilm activity of PHR1 deletion,PHR1 complemetation,RIM101 deletion and RIM101 complemetation strains. For the biofilm damage,PHR1 gene deletion or complementation,RIM101 gene deletion or complementation all showed different degrees of damage; after adding BAEB,the damage rate of PHR1 deletion or complementation was not significantly different,but the damage rate of RIM101 deletion or complementation was significantly increased. Except to the up-regulation of HSP90 gene expression,ALS3,SUN41,HWP1,UME6 and PGA10 genes of PHR1 deletion,PHR1 complementation,RIM101 deletion,and RIM101 complementation strains showed a downward expression trend. In a word,this study showed that mutations in PHR1 and RIM101 genes in the pH signaling pathway could enhance the sensitivity of the strains to the antifungal drug BAEB,thus inhibiting the biofilm formation and related genes expression in C. albicans.
1-Butanol ; Biofilms ; drug effects ; Candida albicans ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Fungal Proteins ; Gene Expression Regulation, Fungal ; Hydrogen-Ion Concentration ; Plant Extracts ; pharmacology ; Signal Transduction

Biofilms at the tooth-restoration bonded interface can produce acids and cause recurrent caries. Recurrent caries is a primary reason for restoration failures. The objectives of this study were to synthesize a novel bioactive dental bonding agent containing dimethylaminohexadecyl methacrylate (DMAHDM) and 2-methacryloyloxyethyl phosphorylcholine (MPC) to inhibit biofilm formation at the tooth-restoration margin and to investigate the effects of water-aging for 6 months on the dentin bond strength and protein-repellent and antibacterial durability. A protein-repellent agent (MPC) and antibacterial agent (DMAHDM) were added to a Scotchbond multi-purpose (SBMP) primer and adhesive. Specimens were stored in water at 37 °C for 1, 30, 90, or 180 days (d). At the end of each time period, the dentin bond strength and protein-repellent and antibacterial properties were evaluated. Protein attachment onto resin specimens was measured by the micro-bicinchoninic acid approach. A dental plaque microcosm biofilm model was used to test the biofilm response. The SBMP + MPC + DMAHDM group showed no decline in dentin bond strength after water-aging for 6 months, which was significantly higher than that of the control (P < 0.05). The SBMP + MPC + DMAHDM group had protein adhesion that was only 1/20 of that of the SBMP control (P < 0.05). Incorporation of MPC and DMAHDM into SBMP provided a synergistic effect on biofilm reduction. The antibacterial effect and resistance to protein adsorption exhibited no decrease from 1 to 180 d (P > 0.1). In conclusion, a bonding agent with MPC and DMAHDM achieved a durable dentin bond strength and long-term resistance to proteins and oral bacteria. The novel dental bonding agent is promising for applications in preventive and restorative dentistry to reduce biofilm formation at the tooth-restoration margin.
Anti-Infective Agents ; chemistry ; pharmacology ; Biofilms ; drug effects ; Dental Bonding ; Dentin-Bonding Agents ; chemistry ; pharmacology ; Materials Testing ; Methacrylates ; chemistry ; pharmacology ; Phosphorylcholine ; analogs & derivatives ; chemistry ; pharmacology ; Resin Cements ; Shear Strength ; Surface Properties ; Water

The aim of this study is to assess the antibacterial and anti-biofilm properties of the lipid extract from Mantidis ootheca against the gentamycin resistant Pseudomonas aeruginosa. The chemical composition of the lipid extract and its relative proportion were determined using the technique of gas chromatography coupled with mass spectrometry (GC-MS). Antibacterial susceptibility tests were performed using a disc diffusion assay and the minimum inhibition concentration (MIC) was determined by way of the agar dilution method. The anti-biofilm test was carried out with crystal violet staining and scanning electron microscopy (SEM). There were 16 compounds detected, and the most abundant components were sesquiterpenoids, monoterpenes, and trace aromatic compounds. The MIC for P. aeruginosa was 4 mg/ml and the eradication effect on preformed biofilms was established and compared with a ciprofloxacin control. The results of our study indicated that a lipid extract from M. ootheca could be used as a topical and antibacterial agent with anti-biofilm activity in the future.
Animals ; Anti-Bacterial Agents ; pharmacology ; Biofilms ; drug effects ; Gas Chromatography-Mass Spectrometry ; Mantodea ; chemistry ; Microbial Sensitivity Tests ; Pseudomonas aeruginosa ; drug effects

Three new alkyl substituted anthraquinone derivatives, trivially named as symploquinones A-C (Compounds 1-3) were isolated from Symplocos racemosa. The structures of these compounds were determined on the basis of extensive spectroscopic analyses (UV, IR, Mass, H- and C-NMR, and two-dimensional (2D) NMR techniques). The resulting data were also compared with the reported literature. These compounds were then subjected to antibacterial or antibiofilm testing. Compounds 1 and 3 exhibited good antibacterial activity in the concentration range of 160-83 μg·mL against Streptococcus mutans, methicillin resistant Staphylococcus aureus and Proteus mirabilis. Both compounds were further screened for anti-biofilm activity, which revealed promising activities at sub-MIC concentrations. None of the compounds were found to be active against Klebsiella pneumoniae.
Anthraquinones ; chemistry ; isolation & purification ; pharmacology ; Anti-Bacterial Agents ; chemistry ; isolation & purification ; pharmacology ; Biofilms ; drug effects ; growth & development ; Ericales ; chemistry ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; physiology ; Microbial Sensitivity Tests ; Proteus mirabilis ; drug effects ; physiology ; Spectrophotometry, Infrared ; Streptococcus mutans ; drug effects ; physiology

Objective To explore the effects of Scutellaria baicalensis on activity and biofilm formation of Klebsiella pneumonia (Kp).Methods The broth and agar dilution Methods were carried out to determine minimum inhibitory concentration and minimum bactericidal concentration of Scutellaria baicalensis for TW518. VITEK-32 system was used to assay TW518 susceptibility to antibiotics. Kp biofilms were formed in vitro and stained with BacLight Live/Dead stain. The class integron geneⅠ1 mRNA expression was analyzed with RT-PCR.Results The minimum inhibitory concentration of Scutellaria baicalensis on TW518 identified as a Kp colony was 32 mg/ml, and minimum bactericidal concentration was 64 mg/ml. Scutellaria baicalensis and broad-spectrum penicillin, cephalosporin, quinolones, or beta-lactamase had synergistic bactericidal effects. Biofilm formation activity of Kp treated with Scutellaria baicalensis was significantly lower than that of the control group. And class integron geneⅠ1 mRNA expression of TW518 was significantly inhibited by Scutellaria baicalensis.Conclusions Scutellaria baicalensis has sterilization effect on Kp, and Scutellaria baicalensis could effectively inhibit Kp biofilm formation with prolonged treatment. Scutellaria baicalensis might inhibit Kp biofilm formation through down-regulating integron geneⅠ1 expression.
Biofilms ; drug effects ; Integrons ; drug effects ; Klebsiella pneumoniae ; drug effects ; physiology ; Microbial Sensitivity Tests ; Scutellaria baicalensis

Bacterial biofilms are considered to be the hindrance in the treatment of chronic wound, because of their tolerance toward antibiotics and other antimicrobial agents. They also have strong ability to escape from the host immune attack. Acetic acid, as a kind of organic weak acid, can disturb the biofilms by freely diffusing through the bacterial biofilms and bacterial cell membrane structure. Then the acid dissociates to release the hydrogen ions, leading to the disorder of the acid-base imbalance, change of protein conformation, and the degradation of the DNA within the membranes. This paper reviews the literature on the characteristics and treatment strategies of the bacterial biofilms and the acetic acid intervention on them, so as to demonstrate the roles acetic acid may play in the treatment of chronic wound, and thus provide a convincing treatment strategy for this kind of disease.
Acetic Acid ; pharmacology ; Anti-Bacterial Agents ; pharmacology ; Biofilms ; drug effects ; Humans ; Wound Healing

OBJECTIVETo evaluate the effect of 2-methacryloyloxyethyl phosphorylcholine (MPC) and nanoparticles of amorphous calcium phosphate (NACP) on the protein-repellent property of dental adhesive.

METHODSMPC and NACP were incorporated into SBMP as the test group. Scotchbond Multi-Purpose (SBMP) was used as control group. Human dentin shear bond strengths were measured. Protein adsorption onto samples was determined by micro bicinchoninic acid (BCA) method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm viability.

RESULTSThe dentin bond strength of modified group was (28.7±2.2) MPa, which was not significantly different from that of the SBMP control group. The amount of protein adsorption in the modified group and the SBMP control group were (0.21±0.02) µg/cm(2) and (4.17±0.45) µg/cm(2) respectively. Lactic acid production of biofilms in modified group and SBMP control were (7.71 ± 1.01) mmol/L and (19.18 ± 2.34) mmol/L repectively.

CONCLUSIONSMPC-NACP based dental adhesive greatly reduce the protein adsorption and bacterial adhesion, without compromising dentin shear bond strength. This novel bonding agent may have wide application.

Adsorption ; Biofilms ; drug effects ; growth & development ; Calcium Phosphates ; pharmacology ; Dental Cements ; pharmacology ; Dental Plaque ; Dentin ; chemistry ; Humans ; Lactic Acid ; biosynthesis ; Methacrylates ; pharmacology ; Nanoparticles ; Phosphorylcholine ; analogs & derivatives ; pharmacology ; Resin Cements ; pharmacology ; Saliva ; Tensile Strength

Tooth bleaching agents contain powerful oxidizing agents, which serve as the main part of bleaching agents because of its release of effective bleaching component. It has been a hot topic whether tooth bleaching agents exert negative influence on oral health. In order to provide train of thoughts and reference for further clinical researches and treatments, this review paper focuses on bleaching agents' effects on the growth of oral microbes and the formation of biofilms.
Bacteria ; drug effects ; growth & development ; Biofilms ; drug effects ; growth & development ; Humans ; Hydrogen Peroxide ; Mouth ; microbiology ; Oral Health ; Oxidants ; pharmacology ; Tooth Bleaching ; Tooth Bleaching Agents ; pharmacology

OBJECTIVETo study the effect of extracellular DNA(eDNA) on the formation of Streptococcus mutans(Sm) biofilms during different growth periods in sucrose environment.

METHODSSm biofilms were established on smooth glass surfaces under the environment of 1% sucrose and cultured in the condition of 37 ℃, 5% O2, 85% N2 and 10% CO2. Samples were randomly divided into four groups based on fourculture time(6,12, 24 and 48 h), respectively. Each group was further divided into two subgroups: control group(without deoxyribonuclease Ⅰ[DNaseⅠ] treatment) and test group(with DNaseⅠtreatment). DNaseⅠ was added 1 h advance in the treatment group to a final concentration of 100 U/ml. Each sample was stained with mixed SYTO-9/PI fluorescent dye. Confocal laser scanning microscopy was used for biofilm observation and scanning. The total biomass, the thickness and the volume of red fluorescence of each biofilm sample were measured following three-dimensional reconstruction using the softwear of Imaris 7.2.3.

RESULTSUnder the environment of 1% sucrose, the Sm bacterial adhesion and distribution density increased over time, the quantity of eDNA and membrane-damaged bacteria which were indicated by red fluorescence also increased within 24 h but dropped later. The biofilm biomasses of Sm biofilm in 6, 12, 24 and 48 h DNaseⅠ treatment group reduced significantly(P<0.05) compared to those in the corresponding control groups by 81.3%, 85.0%, 90.1% and 12.4%, respectively. The biofilm thicknesses in each DNase Ⅰ treatment group (except 6 h group) also reduced significantly(P<0.05) compared to those in the corresponding control group by 34.4%, 45.6% and 23.6%, respectively. The quantities of eDNA and membrane-damaged bacteria reduced in each treatment group except 48 h group compared to that in the corresponding control group.

CONCLUSIONSUnder the environment of 1% sucrose, eDNA plays an important role in promoting the formation of Sm biofilm.

Bacterial Adhesion ; drug effects ; Biofilms ; growth & development ; DNA ; physiology ; Deoxyribonuclease I ; pharmacology ; Microscopy, Confocal ; Streptococcus mutans ; physiology ; Sucrose ; Sweetening Agents ; Temperature