Objective To study the influence of brominated furanones on the biofilm (BF) formation of Staphylococcus epidermidis (SE) on polyvinyl chloride(PVC) materials, and provide new ideas for the research of surface modification of materials and clinical treatment of biomaterial centered infection. Methods We chose three kinds of brominated furanone with representative chemical structure for our research which were respectively 3,4dibromo-5-hydroxy2 (5H) -furanone (Mucobromic acid) in the first furanone group, 4-bromo-5(4-methoxyphenyl)3(methylamino)2(5H)furanone in the second furanone group, and 3,4dibromo-5,5-bis(4-methylphenyl)2(5H)-furanone in the third furanone group. The PVC material soaked with 75% ethanol for 5minutes was classified as the control group. The surface coating of the PVC materials in the four groups all underwent modification respectively and then they were cocultivated with staphylococcus epidermidis together. Confocal laser scanning microscope(CLSM) was adopted to detect the thickness of bacterium BF and bacterium community quantity unit area on PVC materials and scanning electron microscope(SEM) was used to observe surface structure of SE, BF formation at 6 h, 12 h, 18 h and 24 h respectively. Results The results of CLSM showed that, compared with the control group, SE bacterium community quantity unit area and the thickness of bacterium BF on the PVC material surface in the second furanone group were obviously smaller (Plt;0.05). SE bacterium community quantity unit area and thickness of bacterium BF on PVC material surface in the first and the third furanone groups had no significant difference (Pgt;0.05). The result of SEM showed that, the quantity of SE bacterium community unit area on PVC material surface in the second furanone group were smaller than that of the control group at 6 hours. The biofilm structure on PVC material surface in the control group was formed at 18 hours, but there were no mature biofilm structure on PVC material surface in the second furanone group at 18 hours. Conclusion The impact of different brominated furanone on SE biofilm formation on the surface of PVC materials is different. The second kind of furanone can inhibit the quantity of SE bacterium community unit area and SE biofilm formation on the surface of PVC materials.
Objective The intercellular adhesion (ica) gene of Staphylococcus epidermidis (SE) is a key factor to bacterial aggregation, to analysis the genotype of iatrogenic SE and to explore the effect of iatrogenic SE ica operon on theformation of bacterial biofilm on the surface of polyvinyl chloride (PVC). Methods Fifty-six cl inical isolates of iatrogenic SEwere selected, and PCR and gene sequencing were used to detect the genes related with bacterial biofilm formation. The genes contained 16S rRNA, autolysin (atlE), fibrinogen binding protein (fbe), and icaADB. The bacteria suspension of 1 × 105 cfu/mL iatrogenic SE was prepared; according to the test results of target genes, the PVC material and the genotype of icaADB+, atlE+, fbe+ strains were co-cultivated as the ica positive group; the PVC material and the genotype of icaADB-, atlE+, fbe+ strains were co-cultivated as the ica negative group. The thickness of biofilm and bacterial community quantity unit area on PVC materials were measured by confocal laser scanning microscope, and the surface structure of biofilm formation was observed by scanning electron microscope (SEM) at 6, 12, 18, 24, and 30 hours. Results The positive rate of 16S rRNA of iatrogenic SE strains was 100% (56/56). The genotype of icaADB+, atlE+, and fbe+ strains accounted for 57.1% (32/56). The genotype of icaADB-, atlE+, and fbe+ strains accounted for 37.5% (21/56). The sequencing results showed that the product sequences of 16S rRNA, atlE, fbe, and icaADB were consistent with those in GenBank. With time, no significant bacterial biofilm formed on the surface of PVC in ica operon negative group. But in ica operon positive group, the number of bacterial community was gradually increased, and the volume of bacterial biofilms was gradually increased on the surface of PVC. At 24 hours, mature bacterial biofilm structure formed, and at 30 hours, the volume of bacterial biofilms was tending towards stabil ity. The thickness of biofilm (F=6 714.395, P=0.000) and the bacterial community quantity unit area on PVC materials (F=435.985, P=0.000) in ica operon positive groupwere significantly higher than those in ica operon negative group. Conclusion Iatrogenic SE can be divided into 2 types ofica operon negative and ica operon positive bacteria. The iatrogenic SE ica operon can strengthen bacterium biofilm formation capabil ity on PVC materials, bacterium community quantity, and thickness of biofilm, it plays an important role in bacterium biofilm formation on PVC materials.
Objective To evaluate the effect of hepatocyte growth factor(HGF) on intestinal permeability and bacterial translocation after small bowel transplantation in rats. Methods Twenty Wistar rats were as recptors and twenty SD rats as donors. After heterotopic intestinal grafting, cyclosporine A was administered at 6mg/kg·day intramuscularly for inhibiting rejection. The SD rats were divided into 2 groups(n=10). HGF was administered at 150 μg/kg·day (HGF group) and normal saline was administered at 150 μg/kg·day (controlgroup). Intestinal permeability and bacterial translocation to the mesenteric lymph nodes and portal vein were assessed at the 8th postoperative day. Results The lactulose and lactulose/ mannitol of control group (0.0931%±0.008 5% and 0.132± 0.021) were higher than those of normal reference value (0.015 0%±0.002 0% and 0.020±0.005)（Plt;0.05）. The lactulose and lactulose/ mannitol of HGF group (0.039 6%±0.009 0% and 0.056±0.013) were also higher than those of normal reference value（Plt;0.05）.The bacterial culture positive proportion of lymphaden in HGF group and control group were 10% and 60%, showing statistically significant difference（Plt;0.05）. The bacterial culture positive proportion of portal vein in HGF group and control group were 10% and 20% respectively（P＞0.05）. Conclusion HGF can decrease intestinal permeability and bacterial translocation from the lumen of the graft to the mesenteric lymph nodes,thus improve gut barrier function, may be of help to reduce the incidence of septic complications after intestinal grafting.
Objective To study the role of the complement receptor 1 and 3 ( CR1 and CR3) on neutrophils in distinguishing bacterial infection in patients with acute exacerbation of chronic obstructive pulmonary disease ( AECOPD) . Methods 40 patients with AECOPD were divided into two groups according to the detection of bacteria in subairway. 20 patients with stable COPD and 20 healthy subjects with no history of smoking were also included. According to Anthonisen criteria, 40 AECOPD patients weredivided into type Ⅰ( 11 cases) , type Ⅱ ( 12 cases) , and type Ⅲ( 17 cases) . The levels of CR1 and CR3 in blood were measured by flow cytometry. Results In AECOPD patients, 25 cases were detected bacteria,and 15 cases were not detected bacteria. The level of CR1 and CR3 were highest in the bacterial infection group than other groups, and highest in type Ⅰ AECOPD patients than other types. ROC analysis showed that CR1 and CR3 had good diagnostic value in bacterial infection in AECOPD, with optimal cutoff values of 11 and 52, respectively. Conclusion CR1 and CR3 may be good index of distinguishing bacterial infection in AECOPD.
Objective To design and construct a graphene oxide (GO)/silver nitrate (Ag3PO4)/chitosan (CS) composite coating for rapidly killing bacteria and preventing postoperative infection in implant surgery. Methods GO/Ag3PO4 composites were prepared by ion exchange method, and CS and GO/Ag3PO4 composites were deposited on medical titanium (Ti) sheets successively. The morphology, physical image, photothermal and photocatalytic ability, antibacterial ability, and adhesion to the matrix of the materials were characterized. Results The GO/Ag3PO4 composites were successfully prepared by ion exchange method and the heterogeneous structure of GO/Ag3PO4 was proved by morphology phase test. The heterogeneous structure formed by Ag3PO4 and GO reduced the band gap from 1.79 eV to 1.39 eV which could be excited by 808 nm near-infrared light. The photothermal and photocatalytic experiments proved that the GO/Ag3PO4/CS coating had excellent photothermal and photodynamic properties. In vitro antibacterial experiments showed that the antibacterial rate of the GO/Ag3PO4/CS composite coating against Staphylococcus aureus reached 99.81% after 20 minutes irradiation with 808 nm near-infrared light. At the same time, the composite coating had excellent light stability, which could provide stable and sustained antibacterial effect. ConclusionGO/Ag3PO4/CS coating can be excited by 808 nm near infrared light to produce reactive oxygen species, which has excellent antibacterial activity under light.
Objective To explore the microbiological etiology and antibiotic susceptibility of periopertive urinary tract infection (UTI) in patients undergoing hip or knee arthroplasty, so as to provide recommendations for antibiotic treatment. Methods A retrospective review was conducted for patients with perioperative UTI who underwent hip or knee arthroplasty between January 1st, 2013 and October 1st, 2015. Microbiological data and antibiotic susceptibility of bacteria were analyzed. Results A total of 117 strains of bacteria were identified, including 11 types of species. Among the organisms cultured, 86.3% (101 strains) were gram-negative bacteria, in which Escherichia coli was the most common causative organism (70.9%, 83 strains), followed by Klebsiella species (7.7%, 9 strains) and Proteus mirabilis (3.4%, 4 strains). And among the gram-positive bacteria detected, the proportion of Enterococcus faecalis and Feces Enterococcus was 6.8% (8 strains) and 3.4% (4 strains), respectively. The bacteria showed highly resistance to cephalosporins, quinolones and sulfonamides, but showed high sensitive to nitrofurantoin, carbopenems, the enzyme inhibitor complex and aminoglycoside antibiotics. Conclusions There is a diversity of bacteria involved in UTI, and the top 3 pathogens are Escherichia coli, Enterococcus faecalis and Klebsiella species. The resistance rate is high, and nitrofurantoin, amilacin, piperacillin-tazobactam, cefoperazone-sulbactam are the recommended antibiotics to treat the UTI, but the antibiotic should be adjusted according to susceptibility results.
ObjectiveTo investigate the effect of the estradiol hormones on biofilm formati on and structure of Staphylococcus epidermidis after breast implant surgery. MethodsThe concentration of Staphylococcus epidermidis strains ATCC35984 was adjusted to 1×107 CFU/mL or 1×108 CFU/mL, and the type strains were incubated on the surface of silica gel in 125 pmol/L estradiol suspensions to prepare bacterial biofilms model in vitro. After cultured in vitro for 4, 6, 12, 24, 48, and 72 hours, bacteria growth and biofilm formation ability were assessed by means of the XTT and crystal violet staining respectively. According to the above results, the bacterial suspension concentration was selected for experiments. The experimental concentration of Staphylococcus epidermidis ATCC35984 suspension and the concentrations of 50, 125, 250, 500 pmol/L estradiol suspensions were mixed with silica gel respectively to prepare biofilm model in vitro, no estradiol suspension served as control group. The experimental concentration of Staphylococcus epidermidis ATCC12228 suspension was used to prepare the same model in the negative control. After cultured in vitro for 4, 6, 12, 24, 48, and 72 hours, the same methods were used to assess the bacteria growth dynamics and biofilm forming ability, and the scanning electron microscope (SEM) was used to observe bacterial biofilm structure cultured on the surface of silica gel; the laser scanning confocal microscope (CLSM) was used to measure bacterial biofilm thickness on the surface of silica gel after 6, 12, and 24 hours. ResultsAccording to the results of semi quantitative detection of crystal violet stain and XTT methods, the bacterial suspension of 1×107 CFU/mL was selected for the experiment. XTT results indicated that the growth rates of ATCC12228 strain (at 4, 6, 12, 24, and 72 hours) and ATCC35984 strain (at 4, 6, 24, and 72 hours) in 125, 250, and 500 pmol/L estradiol were significantly faster than those in 0 and 50 pmol/L (P < 0.05). The growth rate of 500 pmol/L group was significantly faster than 125 and 250 pmol/L groups at 4, 6, and 72 hours (P < 0.05), and the growth rate of 250 pmol/L group was significantly faster than that of 125 pmol/L group at 72 hours (P < 0.05), but there was no significant difference between 0 and 50 pmol/L groups (P>0.05). At the same time point and same estradiol concentration, the growth rates showed no significant difference between 2 strains (P>0.05). Semi quantitative detection of crystal violet staining showed no biofilm formed in ATCC12228 strain in all estradiol concentration groups at different time points. In ATCC35984 strain, the biofilm was found at 4 hours and gradually thickened with time, reached the peak at 24 hours. After cultured for 4 and 6 hours, the biofilm of 0 pmol/L groups were significantly thicker than that of 125, 250, and 500 pmol/L groups (P < 0.05). At 12 hours, the 125 pmol/L group had the thickest biofilm, showing significant difference when compared with other groups (P < 0.05). The CLSM showed ATCC35984 biofilm thickness of 125, 250, and 500 pmol/L was significantly less than that of 0 and 50 pmol/L groups at 6 hours (P < 0.05), but difference was not significant between other groups (P>0.05). Then the thickness of the biofilm increased gradually, and the thickness of 125 pmol/L group was significantly larger than that of other concentration groups at 12 and 24 hours (P < 0.05). The SEM observation showed that the biofilm of 125 pmol/L group was denser and thicker than that of the other concentration groups at each time point. ConclusionHigh level estradiol can promote bacteria growth, biofilm formation, and biofilm maturity of Staphylococcus epidermidis.
ObjectiveTo analyze the prognostic factors of patients with bacterial bloodstream infection sepsis and to identify independent risk factors related to death, so as to potentially develop one predictive model for clinical practice. Method A non-intervention retrospective study was carried out. The relative data of adult sepsis patients with positive bacterial blood culture (including central venous catheter tip culture) within 48 hours after admission were collected from the electronic medical database of the First Affiliated Hospital of Dalian Medical University from January 1, 2018 to December 31, 2019, including demographic characters, vital signs, laboratory data, etc. The patients were divided into a survival group and a death group according to in-hospital outcome. The risk factors were analyzed and the prediction model was established by means of multi-factor logistics regression. The discriminatory ability of the model was shown by area under the receiver operating characteristic curve (AUC). The visualization of the predictive model was drawn by nomogram and the model was also verified by internal validation methods with R language. Results A total of 1189 patients were retrieved, and 563 qualified patients were included in the study, including 398 in the survival group and 165 in the death group. Except gender and pathogen type, other indicators yielded statistical differences in single factor comparison between the survival group and the death group. Independent risk factors included in the logistic regression prediction model were: age [P=0.000, 95% confidence interval (CI) 0.949 - 0.982], heart rate (P=0.000, 95%CI 0.966 - 0.987), platelet count (P=0.009, 95%CI 1.001 - 1.006), fibrinogen (P=0.036, 95%CI 1.010 - 1.325), serum potassium ion (P=0.005, 95%CI 0.426 - 0.861), serum chloride ion (P=0.054, 95%CI 0.939 - 1.001), aspartate aminotransferase (P=0.03, 95%CI 0.996 - 1.000), serum globulin (P=0.025, 95%CI 1.006 - 1.086), and mean arterial pressure (P=0.250, 95%CI 0.995 - 1.021). The AUC of the prediction model was 0.779 (95%CI 0.737 - 0.821). The prediction efficiency of the total score of the model's nomogram was good in the 210 - 320 interval, and mean absolute error was 0.011, mean squared error was 0.00018. Conclusions The basic vital signs within 48 h admitting into hospital, as well those homeostasis disordering index indicated by coagulation, liver and renal dysfunction are highly correlated with the prognosis of septic patients with bacterial bloodstream infection. Early warning should be set in order to achieve early detection and rescue patients’ lives.
【Abstract】Objective To study the effects of Chinese traditional medicine Sanqizonggan on bacterial translocation in rats with acute necrotizing pancreatitis (ANP).Methods The rat model of ANP was established by retrograde bilepancreatic duct injection of 5% sodium taurocholate. All rats were randomly divided into three groups: the shamoperation group(n=30), ANP group(n=30), and ANP+Chinese traditional medicine group (n=30). The serum amylase was detected at 0 h,12 h,24 h, and oneweek survival rate and pancreatic histological changes were observed in three groups, and the bacterial translocation from intestinal lumen was examined. Results The survival rate of the group treated with Chinese traditional medicine was significantly higher than that of the ANP group. The rate of bacterial translocation in the treated group significantly decreased. Conclusion The Chinese traditional medicine Sanqizonggan can promote gastrointestinal movement, protect intestinal mucosa and reduce bacterial translocation from intestinal lumen.
Objective To investigate the effect of aureolysin （Aur） on staphylococcus aureus biofilm formation of dacron biomaterial surfaces under different Aur concentration. Methods Ninety dacron biomaterials were divided into 3 groups （group A, group IA, control group） with random number table （30 piece in each group）. Dacron biomaterials were put into vials contained staphylococcus aureus （105 CFU/ml） respectively; then Aur was added to make the concentration at 400ng/ml in group A, and group B at 80ng/ml. The thickness and number of staphylococcus aureus biofilm on the surfaces of dacron biomaterials of each group were evaluated by confocal laser microscopy and scanning electron microscopy after incubating 6h, 16h, 24h, 30h, and 48h. Results The thickness and number of staphylococcus aureus biofilm on dacron biomaterials surfaces increased significantly with time dependence in control group. The thickness and number of staphylococcus aureus biofilm in group A were less than those in group B and control group at each time points （P〈0. 05）. The thickness and number in group B were significantly decreased than those in control group （P 〈 0. 05）. Conclusion The study shows that Aur can effectively inhibit the formation of staphylococcus aureus biofilm on dacron biomaterials surfaces with dose dependence.