OBJECTIVETo investigate the biological function of mscL gene in S. epidermidis.

METHODSA plasmid pMAD-δmscL including the upstream and downstream homologous regions of mscL and spectinomycin resistance gene (spc) was constructed and transformed into S. epidermidis 1457 by electroporation with continuous subculture at 42 degrees celsius with shaking. The mscL knockout mutant (SE1457-δmscL) was selected by blue-white colony screening and antibiotic resistance. The D600 and numbers of viable cells were measured in the mutant and parent strains before and after an osmotic downshift of 0.9 M. The effect of the mscL knockout on biofilm formation was assessed using a semi-quantitative microtiter plate assay.

RESULTSThe plasmid pMAD-δmscL was constructed and mscL was deleted from the genome of S. epidermidis 1457. The mscL mutant was verified by PCR of the genomic DNA, direct sequencing and RT-PCR. During the exponential growth phase, the mutant showed significantly reduced ability to survive osmotic downshock in comparison with the wild-type strain but their capacity to form biofilm remained similar.

CONCLUSIONThe mscL gene may be involved in osmoregulation during the logarithmic growth of S. epidermidis, but it dose not affect biofilm formation of the bacterium.

Biofilms ; growth & development ; Gene Knockout Techniques ; Genes, Bacterial ; Plasmids ; Staphylococcus epidermidis ; genetics ; growth & development

Humans ; Hydrogen-Ion Concentration ; Malassezia ; growth & development ; physiology ; Staphylococcus epidermidis ; growth & development ; physiology

OBJECTIVETo study the effects of inhibitory peptide of Staphylococcus epidermidis (SE) biofilm (briefly referred to as inhibitory peptide) on adhesion and biofilm formation of SE at early stage.

METHODSBy using peptide synthesizer, the inhibitory peptide was synthesized with purity of 96.8% and relative molecular mass of 874.4. (1) Solution of SE ATCC 35984 (the same below) was cultivated with inhibitory peptide in the final concentrations of 1-256 µg/mL, and the M-H broth without bacteria solution was used as blank control. The MIC of the inhibitory peptide against SE was determined (n=3). (2) Solution of SE was cultivated with trypticase soy broth (TSB) culture solution containing inhibitory peptide in the final concentrations of 16, 32, 64, 128, and 256 µg/mL (set as inhibitory peptide groups in corresponding concentration), and solution of SE being cultivated with TSB culture medium was used as negative control group. Growth of SE was observed every one hour from immediately after cultivation (denoted as absorbance value), and the growth curve of SE during the 24 hours of cultivation was drawn, with 3 samples in each group at each time point. (3) Solution of SE was cultivated with TSB culture solution containing inhibitory peptide in the final concentrations of 16, 32, 64, 128, and 256 µg/mL (set as inhibitory peptide groups in corresponding concentration), and solution of SE being cultivated with TSB culture medium was used as negative control group. Adhesive property of SE was observed after cultivation for 4 hours (denoted as absorbance value, n=10); biofilm formation of SE was observed after cultivation for 20 hours (denoted as absorbance value, n=10). (4) Solution of SE was cultivated with TSB culture solution containing inhibitory peptide in the final concentration of 128 µg/mL (set as 128 µg/mL inhibitory peptide group), and solution of SE being cultivated with TSB culture medium was used as negative control group. Adhesive property of SE and its biofilm formation were observed with confocal laser scanning microscope (CLSM), and the sample numbers were both 3. Data were processed with one-way analysis of variance, LSD test, and Dunnett T3 test.

RESULTS(1) The MIC of inhibitory peptide against SE exceeded 256 µg/mL. (2) There was no significant difference in the growth curve of SE between inhibitory peptide groups in different concentrations and negative control group. (3) After 4 hours of cultivation, the absorbance values of adhesive property of SE in 256, 128, 64, and 32 µg/mL inhibitory peptide groups were respectively 0.20 ± 0.04, 0.27 ± 0.03, 0.35 ± 0.04, and 0.40 ± 0.04, which were significantly lower than the absorbance value in negative control group (0.53 ± 0.10, P<0.05 or P<0.01); the absorbance value of adhesive property of SE in 16 µg/mL inhibitory peptide group was 0.47 ± 0.09, which was close to the absorbance value in negative control group (P>0.05). After 20 hours of cultivation, the absorbance values of biofilm formation of SE in 256, 128, and 64 µg/mL inhibitory peptide groups were respectively 0.49 ± 0.10, 0.68 ± 0.06, and 0.93 ± 0.13, which were significantly less than the absorbance value in negative control group (1.21 ± 0.18, P<0.05 or P<0.01); the absorbance values of biofilm formation in 32 and 16 µg/mL inhibitory peptide groups were respectively 1.18 ± 0.22 and 1.15 ± 0.26, which were close to the absorbance value in negative control group (with P values above 0.05). (4) CLSM showed that more adhering bacteria and compact structure of biofilm were observed in negative control group, but less adhering bacteria and loose structure of biofilm were observed in 128 µg/mL inhibitory peptide group.

CONCLUSIONSThe inhibitory peptide can inhibit adhesion and biofilm formation of SE at early stage, but its structure still needs to be further modified.

Bacterial Adhesion ; Biofilms ; growth & development ; Humans ; Microscopy, Confocal ; Peptides ; Staphylococcus epidermidis ; genetics ; metabolism ; physiology

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

BACKGROUND: Delayed entry of blood culture bottles is inevitable when microbiological laboratories do not operate for 24 hr. There are few studies reported for prestorage of these bottles. The growth dynamics of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were investigated with respect to various preincubation conditions. METHODS: Fifteen or 150 colony-forming units (CFU) of bacteria were inoculated into standard aerobic or anaerobic blood culture bottles. Bottles were preincubated at 25degrees C or 37degrees C for 0, 2, 4, 8, 12, 24, or 48 hr. The time to detection (TTD) then was monitored using the BacT/Alert 3D system (bioMerieux Inc., USA). RESULTS: Significant difference in TTD was observed following preincubation for 8 hr at 25degrees C vs. 4 hr at 37degrees C for S. aureus, 4 hr at 25degrees C vs. 4 hr at 37degrees C for E. coli, 12 hr at 25degrees C vs. 4 hr at 37degrees C for P. aeruginosa, compared to no preincubation (P<0.005). TTD values did not vary significantly with bacterial CFU or with aerobic or anaerobic bottle type. The BacT/Alert 3D system returned false negatives following preincubation of P. aeruginosa for 48 hr at 25degrees C or 24 hr at 37degrees C. CONCLUSIONS: TTD was mainly affected by preincubation temperature and duration rather than by input CFU quantity or bottle type for the 3 experimental bacteria.
Bacteriological Techniques/instrumentation/*methods ; Culture Media ; Escherichia coli/growth & development/*isolation & purification ; Pseudomonas aeruginosa/growth & development/*isolation & purification ; Staphylococcus aureus/growth & development/*isolation & purification ; Temperature ; Time Factors

Nutrient agar medium was exposed in 0.085-0.092 T static magnetic fields for 12 h. Then we densities the optical densities at lamda = 600 (OD600) of Escherichia coli, Staphylococcus aureus and Bacillus subtilis in different culturing stage. The results were compared with those of control group in the normal geomagnetic field. The OD600 values of experimental groups of these three kinds of aerobes were significantly higher than those of control groups from 3h to 9h. However, after 11 h, there was no remarkable difference regarding the OD600 values between the two groups. The dissolved oxygen content of nutrient agar medium was determined by microtitration. The dissolved oxygen of nutrient agar medium under static magnetic for 12h increased 15% in average and there was significant difference when compared with the control. The results showed that the ferro-magnetic fields increased the dissolved oxygen content of nutrient agar medium significantly. These findings suggest that the effects of static magnetic fields on Escherichia coli, Staphylococcus aureus and Bacillus subtilis are related to the dissolved oxygen.
Bacillus subtilis ; growth & development ; radiation effects ; Culture Media ; radiation effects ; Escherichia coli ; growth & development ; radiation effects ; Magnetic Fields ; Staphylococcus aureus ; growth & development ; radiation effects

The standard iron-chelator deferoxamine is known to prevent the growth of coagulase-negative staphylococci (CoNS) which are major pathogens in iron-overloaded patients. However, we found that deferoxamine rather promotes the growth of coagulase-positive Staphylococcus aureus. Accordingly, we tested whether deferiprone, a new clinically-available iron-chelator, can prevent the growth of S. aureus strains as well as CoNS. Deferiprone did not at least promote the growth of all S. aureus strains (n=26) and CoNS (n=27) at relatively low doses; moreover, it could significantly inhibit the growth of all staphylococci on non-transferrin-bound-iron and the growth of all CoNS on transferrin-bound iron at relatively high doses. At the same doses, it did not at least promote the growth of all S. aureus strains on transferrin-bound-iron. These findings indicate that deferiprone can be useful to prevent staphylococcal infections, as well as to improve iron overload, in iron-overloaded patients.
Deferoxamine/pharmacology ; Humans ; Iron/metabolism ; Iron Chelating Agents/*pharmacology ; Iron Overload/metabolism ; Microbial Sensitivity Tests ; Pyridones/*pharmacology ; Staphylococcus/*drug effects/growth & development ; Staphylococcus aureus/drug effects/growth & development ; Transferrin/metabolism

PURPOSE: Most surgeons have used autogenous cartilage for columella strut graft. But the supply of autogenous cartilage is often limited. So, this study is to investigate the usefulness of biodegradable plate as columella strut material. METHODS: We studied 19 patients who have secondary cleft nasal deformity. Patients were divided into two groups. Group A patients who were not closed their growth plate underwent columella strut graft only with biodegradable plate through endonasal approach. The biodegradable plate was inserted between nasal tip and anterior nasal spine. Group B patients were closed their growth plate. They had an operation for columella strut graft with biodegradable plate fixed with autogenous conchal cartilage. If nasal tip projection was insufficient, we performed additionally onlay graft on nasal tip with autogenous soft tissue or remnant cartilage. RESULTS: As a result of mean 14 months follow-up, we achieved a good nasal tip projection, narrowing of interalar distance and symmetrical nostril shape. No specific complications were reported except 2 cases, which were the extrusion of biodegradable plate into the nasal cavity and Staphylococcus aureus infection. CONCLUSION: The columella strut graft using biodegradable plate is simple and effective method. Biodegradable plate can be a good substitute for columella strut in patients who can not use autogenous cartilages.
Absorbable Implants ; Cartilage ; Congenital Abnormalities ; Follow-Up Studies ; Growth Plate ; Humans ; Inlays ; Nasal Cavity ; Rhinoplasty ; Spine ; Staphylococcus aureus ; Transplants

OBJECTIVETo study and analyze the antibacterial effects of different extracts from Radix Isatis.

METHODSStaphylococcus aureus was used as the studied object in the experiment. Antibacterial effects of extracts from Radix Isatis were observed by thermocalrimetry on Staphylococcus aureus, together with common pharmacological experiments.

RESULTSThe total extract, ethyl acetate (EtOAc) extract, n-butylalcohol (nBuOH) extract, chloroform (CHCl(3)) extract and petroleum (P.E.) extract had antiviral effects to some extent while the residue after extracting had no antibacterial activity. The potency of antiviral activity among them was as follows: nBuOH extract > EtOAc extract > CHCl(3) extract > total extract > P.E. extract.

CONCLUSIONThe antibacteriall effects of Radix Isatis were not limited to any active portion, showing that Radix Isatis exerts its antibacterial effects by cooperation of different active fractions in varied ways.

Anti-Bacterial Agents ; pharmacology ; Calorimetry ; Isatis ; Microbial Sensitivity Tests ; Plant Extracts ; pharmacology ; Plant Roots ; Staphylococcus aureus ; drug effects ; growth & development

In order to confirm whether the migrating larvae of parasites could carry pathogenic organisms into liver and cause hepatitis, a series of experiments has been carried out. The summary of the results is as follows: 1. Clonorchis sinensis A few of the excysted larvae of Clonorchis sinensis penetrated into the peritoneal cavity, but they could not penetrate the liver tissues. The artificially introduced Clonorchis sinensis in the tissues were all destroyed within 3-5 days. There was no manifestation of diffuse inflammatory changes due to the inoculation of the parasites, though the sampled micro-organisms, Staphylococcus aureus, were confirmed from the surrounding area. 2. Hookworm The larvae carried pathogenic organisms to liver tissues either by cutaneous or oral infection, but there was no manifestation of hepatitis due to the micro-organisms: In conclusion, it is indicated that liverfluke and hookworm may transmit pathogenic organisms to the liver during their migration.
Ancylostoma/*physiology ; Animals ; Larva/physiology ; Liver Diseases, Parasitic/*etiology ; Male ; Mice ; Opisthorchis/*physiology ; Rabbits ; Staphylococcus/*growth & development ; Streptococcus pneumoniae/growth & development