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

OBJECTIVETo investigate the effect of antibacterial peptide LL-37 on the integrity of Acinetobacter baumannii biofilm.

METHODSA model of Acinetobacter baumannii biofilm in vitro was constructed by plates and crystal violet staining method, and the minimal inhibitory concentration of LL-37 was determined by broth dilution. The biofilm morphology was observed by scanning electron microscopy and biofilm formation was analyzed by the crystal violet staining of the adherent biofilm in the presence of antibacterial peptide LL-37.

RESULTSIn the Acinetobacter baumannii biofilm model, the minimal inhibitory concentration of LL-37 was 64 µg/ml; LL-37 caused structural damage of the biofilm at a low concentration of 2.5 µg/ml. The biofilm was decreased gradually as the concentration of LL-37 increased.

CONCLUSIONLL-37 even at a concentration far below its minimal inhibitory concentration can cause structural damage of Acinetobacter baumannii biofilm in vitro.

Acinetobacter baumannii ; drug effects ; physiology ; Biofilms ; drug effects ; Cathelicidins ; pharmacology ; Microbial Sensitivity Tests

OBJECTIVETo investigate the relationship among oxygen concentration, quorum sensing system, type secretion system, and biofilm production of Pseudomonas aeruginosa.

METHODSA total of 23 clinical strains of Pseudomonas aeruginosa were cultured at different levels of environmental oxygen for three days. Then biofilm mass and alginate were quantified. The expression levels of LasI and RhlI were detected by real time polymerase chain reaction (PCR). The secretion of exoenzyme S was examined by Western blot.

RESULTSBoth the biofilm mass (R=0.455, P=0.000) and alginate (R=0.367, P=0.000) were positively correlated with oxygen concentration. Real time PCR showed that the expression levels of LasI and RhlI were not significantly correlated with oxygen concentration (R=0.025, P=0.794; R=-0.044, P=0.653), the production of biofilm (R=0.001, P=0.990; R=0.011, P=0.909), or alginate(R=0.029, P=0.770; R=0.193, P=0.064). Western blot showed that the optimal oxygen concentration range for exoenzyme S secretion of Pseudomonas aeruginosa ranged 10% to 30%.

CONCLUSIONSHyperoxia can promote the production of biofilm and alginate by Pseudomonas aeruginosa. Las/Rhl system may not participate in biofilm production at the early stage due to the low bacteria amount. The increased production of biofilm may inhibit the expression of Type Secretion system and thus inhibit bacterial virulence.

Alginates ; metabolism ; Biofilms ; drug effects ; Oxygen ; metabolism ; Pseudomonas aeruginosa ; metabolism ; physiology ; Quorum Sensing ; drug effects ; physiology

OBJECTIVETo investigate the effects of baicalin against Candida glabrata, C. parapsilosis, C. krusei and C. guilliermondii biofilms.

METHOD96-well microtitre plates were used to set up the biofilms; microdilution method was applied to detect minimal inhibitory concentration (MIC) of baicalin for the four non-albians Candida, and XTT reduction assay was adopted to determine sessile minimal inhibitory concentration (SMIC) of baicalin against the four isolates and to detect the effects on adhesion of the fungal cells.

RESULTMICs of baicalin for the four non-albians Candida cells were 125, 250, 125, 62.5 mg L(-1), respectively. The four non-albians Candida could form mature biofilms on 96-well microtitre plates. SMIC50 of baicalin for the four isolates were > 1000, 500, 125, 250 mg x L(-1), respectively. SMIC80 for the four isolates were greater than or equal to 1000 mg x L(-1). Baicalin showed potent inhibitory effects on adhesion of the four non-albians Candida cells.

CONCLUSIONBaicalin displays substantial inhibitory effects on C. parapsilosis, C. krusei and C. guilliermondii biofilm.

Biofilms ; drug effects ; Candida ; drug effects ; physiology ; Flavonoids ; pharmacology ; Microbial Sensitivity Tests

OBJECTIVE: To establish a biofilm model of Haemophilus influenzae and observe the effect of ambroxol on biofilm of Haemophilus influenzae and bactericidal action. METHOD: Thirty strains of Haemophilus influenzae were isolated from adenoids of children with adenoidal hypertrophy. Two strains which could build stronger biofilms was selected in a 96-well plate. The effect of ambroxol on biofilms were determined by crystal violet, and the structure of biofilms were observed by scanning electron microscope (SEM). The numbers of viable bacterial in biofilm after ambroxol treatmented determined by plate culture count. RESULT: Through crystal violet assay, significant difference (P < 0.01) between the two group after treatment was found when ambroxol concentration reached at 0.25 mg/ml and 0.49 mg/ml. The biofilms was destroyed by SEM. Ambroxol had the positive effect on bacterial killing by plate culture count,and the effect was in a dose dependent. CONCLUSION Ambroxol could destroy the biofilm of Haemophilus influenzae, and had bactericidal function in vitro.
Ambroxol ; pharmacology ; Biofilms ; drug effects ; Child ; Child, Preschool ; Haemophilus influenzae ; drug effects ; Humans ; Microbial Sensitivity Tests

OBJECTIVETo investigate the effects of gallic acid against Candida albicans biofilms in vitro.

METHODXTT reduction assay was performed to determine the effect of gallic acid on C. albicans biofilms and its adherence, and microscopic examination was conducted to assess the effect of gallic acid on morphogenesis of C. albicans biofilms; and cytotoxic assay was used to measure the adverse effects of gallic acid.

RESULTSMIC50, SMIC50 of gallic acid against C. albicans biofilms were 500, 1000 mg x L(-1), respectively; 100 mg x L(-1) and 1000 mg x L(-1) of gallic acid could inhibit the initial adherence and filamentous growth, and the agent showed poor cytotoxic activity.

CONCLUSIONgallic acid displayed potent activity against C. albicans biofilm.

Biofilms ; drug effects ; Candida albicans ; cytology ; drug effects ; physiology ; Cell Adhesion ; drug effects ; Dose-Response Relationship, Drug ; Gallic Acid ; pharmacology

OBJECTIVETo provide a new therapeutic approach for Staphylococcus epidermidis biofilm-associated infections by the study of inhibitory effect of andrographolide (AG) on S. epidermidis biofilm.

METHODS. epidermidis biofilms were set up in vitro, erythromycin was acted as the positive control agent, XTT reduction assay was used to evaluate AG on the initial adhesion of S. epidermidis and bacterial metabolism within biofilm, microscope was applied to observe biofilm morphology, and Congo red assay was used to detect polysacchatide interc-ellular adhesion (PIA)formation when exposed to AG.

RESULTAG showed inhibitory effects against the initial adhesion of S. epidermidis at concentrations of 1 000,100, 10 mg x L(-1), respectively,and inhibited metabolism of biofilm bacteria at the concentration of 31.25 mg x L(-1), and exhibited significantly inhibition against the biofilm morphology at the concentration of 250 mg x L(-1), while did not display inhibition against PIA formation at the concentration of 10 mg x L(-1).

CONCLUSIONAG could remarkably inhibit biofilm formation of S. epidermidis, although it was less potent than erythromycin.

Bacterial Adhesion ; drug effects ; Biofilms ; drug effects ; Diterpenes ; pharmacology ; Dose-Response Relationship, Drug ; Erythromycin ; pharmacology ; Staphylococcus epidermidis ; drug effects ; physiology

OBJECTIVETo determine the physicochemical properties of the mutanase of Trichoderma harzianum isolated from China and to study the influence of mutanase on the adherence of oral Streptococci and the structure of oral biofilms.

METHODSSix fungal strains belonging to Trichoderma were tested for mutanase production in the same cultural condition, the strain producing the highest mutanase activity was studied further and the pH and temperature optimum of the enzyme was determined. The RT-PCR method was used to obtain the gene coding for mutanase and the product was cloned to pMD18-T simple vector for sequencing. Inhibition effects of mutanase on the adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 were studied by adherence test. The optical sectioning of biofilms with or without mutanase supplementation were analyzed by confocal laser scanning microscopy (CLSM).

RESULTSThe highest enzymatic activity was achieved by Trichoderma harzianum Th1, the maximum activity was at pH 5.5 and at 40 degrees C. The nucleotide sequence was 92% homology with that of a known gene coding a mutanase (GenBank accession No. AJ243799). The adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 was significantly inhibited by mutanase. Compared with control, the biofilms with mutanase supplementation had lower height and sparser structure.

CONCLUSIONSThe mutanase from Trichoderma harzianum Th1 can inhibit the adherence of oral Streptococci and had an influence on the structure of oral biofilms.

Bacterial Adhesion ; drug effects ; Biofilms ; Glycoside Hydrolases ; chemistry ; physiology ; Streptococcus mutans ; drug effects ; Streptococcus sobrinus ; drug effects ; Trichoderma ; enzymology ; pathogenicity

OBJECTIVETo study the effect of DNase I on biofilm formation of Staphylococcus aureus.

METHODSThe growth curve of S. aureus was detected using a spectrophotometer. The adhesion of S. aureus was analyzed using flat colony counting method, and the biofilm formation was assayed using the 96-well crystal violet staining method.

RESULTSExposure to different concentrations of DNase I did not obviously affect the growth of S. aureus but significantly inhibit the formation of bacterial biofilms in a dose-dependent manner. DNase I inhibited the adhesion of S. aureus at different growth stages. When combined with antibiotics, DNase I resulted in a signi?cant decrease in the established bio?lm biomass compared to antibiotics or DNase I used alone.

CONCLUSIONDNase I can effectively inhibit biofilm formation of S. aureus and enhance the inhibitory effect of antibiotics against S. aureus biofilms.

Anti-Bacterial Agents ; Biofilms ; drug effects ; Deoxyribonuclease I ; chemistry ; Staphylococcus aureus ; growth & development

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