Objective To analyze the current drug resistance and risk factors of hospital acquired pneumonia( HAP) due to extended spectrumβ-lactamase ( ESBLs) producing Escherichia coli and Klebsiella pneumoniae, and to estimate the prevalence trend of ESBLs producing strains. Methods FromApril 2007 to January 2008, 140 patients of Xinhua Hospital with HAP due to E. coli and K. pnermoniae were enrolled.Among them, 88 patients were with ESBLs producing strains and 52 patients were with non-ESBLs producing strains. Risk factors were analyzed by comparing between these patients. The rate of drug resistance was determined by antibiotic sensitive test. Fifty-three ESBLs producing strains were genotyped by random amplified polymorphic DNA ( RAPD) . Results The rate of drug resistance of ESBLs producing strains washigher than that of non-ESBLs producing strains. ICU stay, use of third- and forth-generation cehpalosporin were found to be the independent risk factors by multivariate analysis with logistic regression. By RAPD, 37 ESBLs producing E. coli strains were divided into 27 types and 16 ESBLs producing K. pneumoniae strains were divided into 13 types. Conclusions ICU stay, use of third-generation and forth-generation cehpalosporin remain as major risk factors in the HAP due to ESBLs producing E. coli and K. pneumoniae.RAPD is an economic, quick and credible method for epidemic analysis
Objective To study the influence of brominated furanones on the biofilm formation of Escherichia coli on the polyvinyl chloride (PVC) material, and to provide new ideas for the research of surface modification of materials and cl inicaltreatment of biomaterial centered infection. Methods Three brominated furanones with representative chemical structurewere chosen and coated on the surface modification of PVC materials, respectively [furanone 1: 3, 4-dibromo-5-hydroxy-furanone; furanone 2: 4-bromo-5-(4-methoxyphenyl)-3-(methylamino)-furanone; furanone 3: 3, 4-dibromo-5, 5-bis (4-methylphenyl)- 2 (5H)-furanone]. All the modificated PVC materials and Escherichia coli were co-cultivated. The PVC material soaked with 75% ethanol for 5 minutes and Escherichia coli were co-cultivated together as the control group. The thickness of bacterial community and bacterial community quantity in the unit area on PVC materials were measured by confocal laser scanning microscope (CLSM), and the surface structure of biofilm formation was observed by scanning electron microscope (SEM). Results The CLSM showed that the thickness of bacterial community and the bacterial community quantity in the unit area of PVC materials was significantly less (P lt; 0.05) in furanone 3 group than in control group, but no significant difference (P gt; 0.05) was found between furanone 1, furanone 2 groups and control group. SEM showed that the quantity of bacterial community in the unit area of PVC materials surface in furanone 3 group was fewer than that in control group at 6 hours; the biofilm structure on PVC materials surface formed at 18 hours in control group, furanone 1 group, and furanone 2 group, but there was no mature biofilm structure on PVC materials surface in furanone 3 group at 18 hours. Conclusion The impact of different brominated furanones on Escherichia coli biofilm formation on the surface of PVC materials is different, 3, 4-dibromo-5, 5-bis (4-methylphenyl)-2 (5H)- furanone can inhibit Escherichia coli biofilm formation on the surface of PVC material.
Objective To establish rabbit models of mixture-infectious endophthalmitis induced by exogenous Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Methods A total of 84 eyes of 42 New Zealand white albino rabbits were randomly divided into 4 groups. There were 21 eyes in each group. Rabbit eyes in group 1, 2, 3 and 4 received an intravitreal injection of 0.1 ml of mix bacterium (2times;104 CFU/ ml, including 103 S. aureus and 103 E. coli), S. aureus (104 CFU/ ml), E. coli (104 CFU/ml), and sterilized saline respectively. The eyes were examined by slit-lamp microscopy, ophthalmoscopy, A/B scan, electroretinography (ERG) and bacterial culture of vitreous humors at the timepoints of 6, 12, 24, 48 and 72 hours, and 4, 7, 10, 14 days after intravitreal injection. All eyeballs were then enucleated for histopathological examination. Results Various degrees of inflammatory reactions were presented in the 3 experimental groups after the injection, and the development trend of the disease was nearly the same. In group 1 active intraocular inflammation like anterior chamber exudates, started at 12 hours after injection (which was early than that in group 2 and 3), aggravated between 48 and 72 hours, alleviated slowly from 4 to 7 days, and was obviously better after 10 to 14 days while the corneal neovascularization and vitreous gray opacity begun to form. The bacterial culture was positive in group 1 (100％, 6 hours to 14 days after injection), group 2 (100%, 6 hours to 3 days after injection) and group 3 (100% from 6 hours to 7 days, and 67.67% at 14 days after injection). It was negative for group 2 (7 to 14 days after injection) and group 4 (6 hours to 14 days after injection). The amplitude of ERG b wave dissapeard in group 1 to 3, and decreased less than 30% in group 4 from the 48th hour after injection. Histopathological examination revealed that all intraocular structures infiltrated with inflammatory cells. Conclusion Complicated endophthalmitis rabbit models can be successfully established by intravitreal injection with S. aureus and E. coli.
Expression conditions of induction strategies for the cytoplasmic inclusion bodies (IBs) production of liver targeted interferon IFN-CSP by recombinant Escherichia coli (E.coli) BL21(DE3) were optimized in shake-flask cultures in this study. The factors of the optimized protocol included in the present study were pH, inducer IPTG (isopropyl β-D-thiogalactoside) concentration, culture growth temperature, incubation time and induction point. The effects of those factors were investigated by ‘single variable at a time’ method, aimed to analyze characterization of the recombinant strain. Orthogonal experimental design was further used to optimize the above critical factors for IFN-CSP production. According to the expression optimization result, it was confirmed that the main influence factors were cell density and induction temperature. The IFN-CSP gene expression optimized conditions were:pH value of the culture medium was 6.0, culture temperature 37℃, adding IPTG to final concentration 0.4 mmol/L when the recombinant strain growth density OD600 achieved 0.8 and induction time 4 h. At this point, the IBs represented 74.3% of the total cellular protein. Compared with the non-optimized condition, IFN-CSP production obtained in optimized induction strategies were increased by approx. 1.2-fold. The optimized induction strategy yielded 688.8 mg/L of IFN-CSP, providing experimental data to study the biology activity and productive technology of IFN-CSP.
ObjectiveTo explore the risk factors of community-acquired urinary tract infections caused by extended-spectrum β-lactamase-producing Escherichia coli (ESBLs-producing Escherichia coli). MethodsProspective and retrospective investigation methods were combined, to investigate the hospitalized patients diagnosed with community-acquired urinary tract infections caused by ESBLs-producing Escherichia coli in the Second Affiliated Hospital of Fujian Medical University during July 2012 to December 2014. Statistical analysis was performed using SPSS 19.0 software. The potential risk factors were analyzed by chi-square test or Fisher exact probability method, then, factors with statistical significance identified by single factor analysis were further analyzed by non-conditional logistic regression. ResultsA total of 106 patients were included and divided into a ESBLs group (68 cases) and a control group (38 cases) according to the drug sensitivity test results. The results of single factor analysis indicated: there were significant differences between the ESBLs group and the control group in the use of antibiotics within three months before admission (χ2=11.292, P=0.001), the use of third generation cephalosporin (χ2=11.033, P=0.001), more than three kinds of diseases that could cause urinary tract obstruction (χ2=16.464, P=0.000), anemia (χ2=5.956, P=0.015), indwelling catheter (χ2=6.695, P=0.010), urinary system operations (χ2=9.730, P=0.002). The results of further non-conditional logistic regression analysis showed that more than three kinds of diseases that could cause urinary tract obstruction (OR=14.675, 95%CI 2.699 to 79.796, P=0.002), anemia (OR=7.976, 95%CI 1.785 to 35.632, P=0.007), the use of antibiotics within three months before admission (OR=7.057, 95%CI 1.597 to 31.175, P=0.010), the use of third generation cephalosporin (OR=6.344, 95%CI 1.145 to 35.146, P=0.034) and indwelling catheter (OR=3.844, 95%CI 1.058 to 13.967, P=0.041) were independent risk factors of community-acquired urinary tract infections caused by ESBLs-producing Escherichia coli. ConclusionThe risk factors of community-acquired urinary tract infections caused by ESBLs-producing Escherichia coli include more than three kinds of diseases that could cause urinary tract obstruction, anemia, the use of antibiotics within three months before admission, the use of third generation cephalosporin, and indwelling catheter. The use of antibiotics, especially the third generation cephalosporin, should be strictly controlled, the time of indwelling catheter should be reduced, and the anemia should be corrected, in order to reduce the incidence of community-acquired urinary tract infections caused by ESBLsproducing Escherichia coli.
ObjectiveTo evaluate the burden of carbapenem-resistant Klebsiella pneumoniae (CRKPN) and carbapenem-resistant Escherichia coli (CRECO), two types of carbapenem-resistant Enterobacteriaceae (CRE), in pediatric patients in Jiangxi Province.MethodsA retrospective investigation was carried out for the distribution of CRKPN/CRECO in pediatric (neonatal group and non-neonatal group) and adult patients in 30 hospitals in Jiangxi Province from January 2016 to December 2018, and the changing trends and detection situations of different patients and types of hospitals were compared and analyzed.ResultsFrom 2016 to 2018, the annual resistance rates of Klebsiella pneumoniae and Escherichia coli to carbapenem in pediatric patients were 5.89%, 4.03%, and 4.24%, respectively, showed a downward trend (χ2trend=5.568, P=0.018). The resistance rate of Klebsiellae pneumoniae and Escherichia coli to carbapenem in neonatal group was higher than that in non-neonatal group (8.44% vs. 3.40%; χ2=63.155, P<0.001) and adult group (8.44% vs. 3.45%; χ2=97.633, P<0.001). In pediatric patients, the 3-year carbapenem resistance rate of Klebsiella pneumoniae was higher than that of Escherichia coli (9.10% vs. 2.48%; χ2=128.177, P<0.001). In non-neonatal pediatric patients, the 3-year resistance rate of Klebsiella pneumoniae and Escherichia coli to carbapenem in maternity and children hospitals was higher than that in general hospitals (4.35% vs. 1.36%; χ2=25.930, P<0.001). CRKPN/CRECO detected in pediatrics were mainly isolated from sputum (31.64%), blood (24.36%), urine (13.82%), and pus (8.36%).ConclusionAlthough the overall resistance rate of Klebsiella pneumoniae and Escherichia coli to carbapenem in pediatric patients showed a downward trend, that in neonatal patients was still high, and the monitoring and prevention and control measures of CRE should be strengthened in neonatal patients.