BACKGROUND The upsurge of antibiotic resistance is a significant challenge to public health,and the dry pipeline of new antibiotics has prompted the discovery of alternative treatment approaches.Enterococcus faecalis(...BACKGROUND The upsurge of antibiotic resistance is a significant challenge to public health,and the dry pipeline of new antibiotics has prompted the discovery of alternative treatment approaches.Enterococcus faecalis(E.faecalis)isolates are often multidrugresistant,posing challenges to antibiotic therapy.Bacteriophage therapy is being explored as an alternative method to treat the growing population of antibioticresistant infections.Nevertheless,many inherent limitations of phages diminish their therapeutic utility,notably the restricted host range and quick development of mutants.The specific types and quantities of bacteriophages and antibiotics may be crucial in generating the optimal phage-antibiotic synergy.AIM To optimize the doses,order,and timing to optimize the synergy of phages and vancomycin on different bacteria states.METHODS A volume of 180μL of E.faecalis bacteria in the logarithmic growth phase,with a concentration of approximately 1×10^(8)colony forming units(CFUs)/mL,was introduced onto a microtitre plate.Subsequently,20μL of phage suspension(1×10^(6)PFUs/mL),vancomycin(16μg/mL),or a combination of both was introduced into the designated wells in the specified sequence and incubated at 37°C for 48 hours.The number of live bacteria was counted at different time points using standardized CFU counting protocols.RESULTS The biofilm model demonstrated that combining phages with vancomycin can eradicate the biofilm.Sequential therapy,involving phage application 8 hours before the antibiotic at a concentration of 108 PFUs/mL,proved the most efficient in eliminating the biofilms and killing the planktonic form of E.faecalis.CONCLUSION The combination of phageɸEFP01 at a higher concentration with a subinhibitory concentration of vancomycin yields a synergistic antibacterial outcome on E.faecalis strain resistant to vancomycin.展开更多
Objective:To determine the inhibition mechanisms of secretome protein extracted from Paenibacillus polymyxa Kp10(Kp10)and Lactococcus lactis Gh1(Gh1)against methicillin-resistant Staphylococcus aureus(MRSA)and vancomy...Objective:To determine the inhibition mechanisms of secretome protein extracted from Paenibacillus polymyxa Kp10(Kp10)and Lactococcus lactis Gh1(Gh1)against methicillin-resistant Staphylococcus aureus(MRSA)and vancomycin-resistant Enterococcus(VRE).Methods:The sensitivity and viability of MRSA and VRE treated with secretome proteins of Kp10 and Gh1 were determined using minimal inhibitory concentration,minimum bactericidal concentration,and time-to-kill assays.The morphological changes were observed using scanning electron microscopy and transmission electron microscopy.To elucidate the antimicrobial mechanism of secretome protein of Kp10 and Gh1 against MRSA and VRE,2D gel proteomic analysis using liquid chromatography-mass spectrometry was run by comparing upregulated and downregulated proteins,and the proton motive force study including the efflux of ATP,pH gradient,and the membrane potential study were conducted.Results:MRSA and VRE were sensitive to Kp10 and Gh1 secretome protein extracts and displayed apparent morphological and internal composition changes.Several proteins associated with cellular component functions were either downregulated or upregulated in treated MRSA and VRE by changing the membrane potential gradient.Conclusions:Kp10 and Gh1 secretome proteins reduce the growth of VRE and MRSA by damaging the cell membrane.Cell division,cell wall biosynthesis,and protein synthesis are involved in the inhibition mechanism.展开更多
Background Vancomycin resistant enterococci(VRE)are now considered a global public health issue.In this study,we explored the relationship between vancomycin resistance incidence and various demographic and climatic f...Background Vancomycin resistant enterococci(VRE)are now considered a global public health issue.In this study,we explored the relationship between vancomycin resistance incidence and various demographic and climatic factors.Methods This retrospective study was performed between January 1st,2014 and December 31st,2021.Data covering the consumption of vancomycin,the prevalence of vancomycin resistance,and relevant demographics were collected.Spearman's rank correlation,beta regression,and spatial statistical analysis were performed using R version 4.2.2 and ArcGIS version 10.7.Results Spearman's rank correlation described the positive relation between vancomycin consumption and the prevalence of vancomycin resistant Enterococcus faecium(VRE_(fm)).Multiple regression analysis showed that vancomycin consumption,rural population,proportion of population aged≥65,annual temperature,and bed number in medical institutions per thousand people were significantly correlated with VRE_(fm)prevalence(r=56.22,p<0.001;r=0.0002,p<0.001;r=0.06,p<0.001;r=−0.07,p<0.001;and r=−0.37,p<0.001,respectively).Conclusions Vancomycin utilization was the predominant factor contributing to VRE_(fm)resistance;the effects of rural populations and the proportion of the population aged≥65 were significant but relatively minimal.Annual temperature and the number of beds in medical institutions per thousand people were protective factors against VRE_(fm).展开更多
Background Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci （VRE） ...Background Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci （VRE） endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong. Methods We described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing （MLST） was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE. Results Between November 26 and December 17, 2011, 11 patients （1 exogenous case and 10 secondary cases） in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% （10/361）. There were 8 males and 3 females with a median age of 78 years （range, 40-87 years）. MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay （P 〈0.001）, a higher proportion with chronic cerebral and cardiopulmonary conditions （P=0.001）, underlying malignancies （P 〈0.001）, and presence of urinary catheter （P 〈0.001）, wound or ulcer （P 〈0.001）, and a greater proportion of these patients were receiving β-lactam/ β-1actamase inhibitors （P=0.009）, carbapenem group （P 〈0.001）, fluoroquinolones （P=0.003）, or vancomycin （P=0.001） when compared with the controls. Conclusion Extensive contact tracing and screening with a ＂search-and-confine＂ strategy was a successful tool for outbreak control in our healthcare reqion.展开更多
Background:Vancomycin-resistant Enterococcus faecium ventriculitis is one of the most severe events in postneurosurgical intracranial infections.There are no guidelines recommending an appropriate treatment before.Cas...Background:Vancomycin-resistant Enterococcus faecium ventriculitis is one of the most severe events in postneurosurgical intracranial infections.There are no guidelines recommending an appropriate treatment before.Case presentation:This case presents a successful linezolid treatment for post-neurosurgical vancomycin-resistant Enterococcus faecium ventriculitis of a 24-year-old man in the department of neurosurgery,Beijing Tiantan Hospital.Conclusions:Linezolid should be considered as one of the important methods for the treatment of postneurosurgical intracranial infections caused by vancomycin-resistant Enterococcus.展开更多
Background The incidence of vancomycin-resistant enterococci （VRE） appeared to be increasing in China, but very few nosocomial outbreaks have been reported. Our hospital had experienced an outbreak of VRE since Marc...Background The incidence of vancomycin-resistant enterococci （VRE） appeared to be increasing in China, but very few nosocomial outbreaks have been reported. Our hospital had experienced an outbreak of VRE since March 2008 to March 2009. The objective of this study was to analyze the molecular features of the isolates and the control measures used to eradicate a VRE outbreak in a tertiary institution in China.Methods We characterized VRE isolates from 21 infected and 11 colonized inpatients from a single hospital by pulsed field gel electrophoresis （PFGE）, multilocus sequence typing （MLST）, the analysis of Tn 1546-like elements and virulence genes detection. Infection control measures, including more environmental disinfection, screening for VRE colonization,contact precautions, education and strict antibiotic restriction, were implemented to control the outbreak.Results During the outbreak, a total of 32 VRE strains were obtained. There were 21 strains found in Emergency Intensive Care Unit （EICU）, 9 isolates from Geriatric Ward, and two from other units. All the isolates harbored the vanA gene, however,four of them exhibited the VanB phenotype. Meanwhile, MLST analysis revealed that all isolates belonged to clonal complex （CC） 17. With the infection-control measures, the epidemic was constrained in two units （EICU and Geriatric Ward）. After March 2009, no further case infected with VRE was detected in the following one-year period.Conclusion The outbreak was controlled by continuous implementation of the infection control programme, and more rigorous infection control policy is needed.展开更多
This study provides different opinion for exploring the mechanism of catechin(CAT)relieving nonalcoholic steatohepatitis(NASH),it is more innovative to explore from the perspective of intestinal microorganism.Through ...This study provides different opinion for exploring the mechanism of catechin(CAT)relieving nonalcoholic steatohepatitis(NASH),it is more innovative to explore from the perspective of intestinal microorganism.Through in vitro fermentation experiments,CAT could improve the abundance of Enterococcus,and Enterococcus faecalis(EF)accounts for the vast majority of Enterococcus in human gut.The experimental results in vivo showed that EF group and CAT+EF group could reduce the body weight,liver index and epididymal fat index of NASH mice,and improve the changes of serum and liver indexes.Hematoxylin-eosin staining observation showed that these two groups have greatly improved the fatty degeneration,balloon degeneration and necrotic focus caused by NASH.The alleviation of CAT+EF group was more obvious.Results of targeted metabonomics showed that CAT could promote EF to produce more methyl palmitate(C_(16:0)),which plays a great role in relieving NASH.Our results indicated that EF could alleviate NASH and CAT+EF group had better alleviation may due to more production of methyl palmitate(C_(16:0))by EF.This study provides a new idea for CAT to alleviate NASH.展开更多
The rough crystal of exopolysaccharide produced by Enterococcus durans, a strain of lactic acid bacteria screened from the intestine of a cock in our laboratory, was purified by CM-cellulose column chromatography, DEA...The rough crystal of exopolysaccharide produced by Enterococcus durans, a strain of lactic acid bacteria screened from the intestine of a cock in our laboratory, was purified by CM-cellulose column chromatography, DEAE-Sephadex A-25 ionexchange and Sephadex G-100 gel chromatography to give EPS-Ⅰ. The EPS-Ⅰ was eluted as a single peak in HPLC analysis, indicating the homogeneity of EPS-Ⅰ and free from low-molecular-weight polysaccharides. The molecular weight of the EPS-Ⅰ was determined as 42 000 by the light scattering method. The result of its elemental analysis was C 41.08% and H 7.23% without the elements of N, P and S. Monosaccharide analysis showed that it was composed of Glc and Man in a molar ratio of 4∶1. Sugar composition analysis, methylation analysis and 1H and 13C NMR spectroscopy revealed that the EPS-Ⅰ was composed of pentasaccharide repeating units. The sequence of sugar residues was determined by using two-dimensional NMR, including heteronuclear multiple-bond correlation(HMBC) and nuclear overhauser effect spectroscopy(NOESY). The structure of the pentasaccharide repeating unit of EPS-Ⅰ was given, a new excellular polysaccharide from lactic acid bacterium compared with other EPSs was reported.展开更多
FabB和FabF是大肠杆菌(Escherichia.coli)脂肪酸合成的关键酶.生物信息学分析显示,粪肠球菌基因组中有2个与大肠杆菌fabF同源的基因:fabF1和fabF2,缺少与fabB同源的基因.用粪肠球菌(Enterococcus faecalis)V583总DNA为模板,PCR扩增fabF1...FabB和FabF是大肠杆菌(Escherichia.coli)脂肪酸合成的关键酶.生物信息学分析显示,粪肠球菌基因组中有2个与大肠杆菌fabF同源的基因:fabF1和fabF2,缺少与fabB同源的基因.用粪肠球菌(Enterococcus faecalis)V583总DNA为模板,PCR扩增fabF1和fabF2基因,以pBAD24为载体,构建了重组质粒pHW13(fabF1)和pHW14(fabF2).体内体外研究显示:fabF1基因能互补大肠杆菌fabB突变,FabF1具有β酮脂酰ACP合成酶Ⅰ(FabB)活性;fabF2能互补大肠杆菌fabF突变,FabF2具有β酮脂酰ACP合成酶Ⅱ(FabF)活性.同时发现粪肠球菌FabF2不同于大肠杆菌FabF,它还拥有微弱β酮脂酰ACP合成酶Ⅰ(FabB)活性,可使大肠杆菌fabB突变株产生少量的不饱和脂肪酸.上述结果表明,FabF类酶(FabF like enzyme)同样可以具有β酮脂酰ACP合成酶Ⅰ(FabB)活性.展开更多
Resistance against commonly used antibiotics is a serious clinical problem in recent medical practice. There exist several bacterial strains in which the possibilities of their inhibition are very limited due to multi...Resistance against commonly used antibiotics is a serious clinical problem in recent medical practice. There exist several bacterial strains in which the possibilities of their inhibition are very limited due to multidrug resistance. Antimicrobial photodynamic therapy (aPDT) represents an option how to effectively suppress the growth of resistant pathogens. In this work we have studied interactions of potent photosensitizer hypericin (Hyp) with hospital-related gram positive (Gram+) and gram negative (Gram-) bacterial strains and the effects of photodynamic activated Hyp on bacterial susceptibility and/or resistance of these strains to antibiotics. We demonstrated a significant influence of photoactivated Hyp on growth of Staphylococcus aureus and Enterococcus sp. We have also shown that it is extremely important to use the effective concentrations of Hyp for aPDT, which completely inhibit the growth of microorganisms. Otherwise, there appears an increase in resistance, probably due to the activation of efflux mechanisms, which are involved in the efflux of Hyp and antibiotics as well.展开更多
AIM: To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). METHODS: Multiplex polymerase chain reac...AIM: To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). METHODS: Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n =16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro. RESULTS: A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of theasa1 gene and thegelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain ofEnterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent amongEnterococcus strains isolated from children with IBD than in control strains. CONCLUSION: Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.展开更多
In the current study, we sought to investigate whether lysed Enterococcus faecalis FK-23 （LFK）, a heat-killed probiotic preparation, attenuated eosinophil influx into the upper airway and had immunomodulatory activi...In the current study, we sought to investigate whether lysed Enterococcus faecalis FK-23 （LFK）, a heat-killed probiotic preparation, attenuated eosinophil influx into the upper airway and had immunomodulatory activity in a murine allergic rhinitis model. Eighteen BALB/c mice were divided into three groups; the ovalbumin （OVA）-sen- sitized/challenged group, which received saline orally for 6 weeks （OVA group）, the OVA-sensitized/challenged group, which received LFK orally for 6 weeks （LFK-fed group）, and the non-sensitized group, which received saline for 6 weeks （saline control group）. Nasal rubbing and sneezing were monitored during the study. After the final challenge, interleukin （IL）-4, interferon （IFN）-y, and OVA-specific IgE levels in the sera and splenocyte culture supernatants were determined, eosinophilic infiltrate into the upper airway was quantified, and splenic CD4~CD25＋ regulatory T cells （Tregs） were examined by flow cytometry. We found that nasal rubbing was sig- nificantly reduced in LFK-fed mice compared to the OVA group on d 27 and 35, and sneezing was significantly inhibited by LFK administration for 35 d. LFK-fed mice had significantly less eosinophil influx into the nasal mucosa than the OVA group. There were no significant differences between the LFK-fed group and OVA group in the serum and splenocyte culture supernatant levels of IL-4, IFN-y, and OVA-specific IgE. Interestingly, the LFK-fed mice had a significantly greater percentage of splenic CD4＋CD25＋ Tregs than OVA group. Our results indicate that oral administration of LFK may alleviate nasal symptoms, reduce nasal eosinophilia, and increase the percentage of CD4＋CD25＋ Tregs in experimental allergic rhinitis.展开更多
文摘BACKGROUND The upsurge of antibiotic resistance is a significant challenge to public health,and the dry pipeline of new antibiotics has prompted the discovery of alternative treatment approaches.Enterococcus faecalis(E.faecalis)isolates are often multidrugresistant,posing challenges to antibiotic therapy.Bacteriophage therapy is being explored as an alternative method to treat the growing population of antibioticresistant infections.Nevertheless,many inherent limitations of phages diminish their therapeutic utility,notably the restricted host range and quick development of mutants.The specific types and quantities of bacteriophages and antibiotics may be crucial in generating the optimal phage-antibiotic synergy.AIM To optimize the doses,order,and timing to optimize the synergy of phages and vancomycin on different bacteria states.METHODS A volume of 180μL of E.faecalis bacteria in the logarithmic growth phase,with a concentration of approximately 1×10^(8)colony forming units(CFUs)/mL,was introduced onto a microtitre plate.Subsequently,20μL of phage suspension(1×10^(6)PFUs/mL),vancomycin(16μg/mL),or a combination of both was introduced into the designated wells in the specified sequence and incubated at 37°C for 48 hours.The number of live bacteria was counted at different time points using standardized CFU counting protocols.RESULTS The biofilm model demonstrated that combining phages with vancomycin can eradicate the biofilm.Sequential therapy,involving phage application 8 hours before the antibiotic at a concentration of 108 PFUs/mL,proved the most efficient in eliminating the biofilms and killing the planktonic form of E.faecalis.CONCLUSION The combination of phageɸEFP01 at a higher concentration with a subinhibitory concentration of vancomycin yields a synergistic antibacterial outcome on E.faecalis strain resistant to vancomycin.
基金supported by the funds of Ministry of Higher Education,Malaysia and Universiti Putra Malaysia through Fundamental Research Grant Scheme (FRGS/1/2017/SKK11/UPM/01/1) and Putra Grant (GP/2017/9571800)
文摘Objective:To determine the inhibition mechanisms of secretome protein extracted from Paenibacillus polymyxa Kp10(Kp10)and Lactococcus lactis Gh1(Gh1)against methicillin-resistant Staphylococcus aureus(MRSA)and vancomycin-resistant Enterococcus(VRE).Methods:The sensitivity and viability of MRSA and VRE treated with secretome proteins of Kp10 and Gh1 were determined using minimal inhibitory concentration,minimum bactericidal concentration,and time-to-kill assays.The morphological changes were observed using scanning electron microscopy and transmission electron microscopy.To elucidate the antimicrobial mechanism of secretome protein of Kp10 and Gh1 against MRSA and VRE,2D gel proteomic analysis using liquid chromatography-mass spectrometry was run by comparing upregulated and downregulated proteins,and the proton motive force study including the efflux of ATP,pH gradient,and the membrane potential study were conducted.Results:MRSA and VRE were sensitive to Kp10 and Gh1 secretome protein extracts and displayed apparent morphological and internal composition changes.Several proteins associated with cellular component functions were either downregulated or upregulated in treated MRSA and VRE by changing the membrane potential gradient.Conclusions:Kp10 and Gh1 secretome proteins reduce the growth of VRE and MRSA by damaging the cell membrane.Cell division,cell wall biosynthesis,and protein synthesis are involved in the inhibition mechanism.
基金supported by grants from the National Natural Science Foundation of China(No.72304275 and No.82273696).
文摘Background Vancomycin resistant enterococci(VRE)are now considered a global public health issue.In this study,we explored the relationship between vancomycin resistance incidence and various demographic and climatic factors.Methods This retrospective study was performed between January 1st,2014 and December 31st,2021.Data covering the consumption of vancomycin,the prevalence of vancomycin resistance,and relevant demographics were collected.Spearman's rank correlation,beta regression,and spatial statistical analysis were performed using R version 4.2.2 and ArcGIS version 10.7.Results Spearman's rank correlation described the positive relation between vancomycin consumption and the prevalence of vancomycin resistant Enterococcus faecium(VRE_(fm)).Multiple regression analysis showed that vancomycin consumption,rural population,proportion of population aged≥65,annual temperature,and bed number in medical institutions per thousand people were significantly correlated with VRE_(fm)prevalence(r=56.22,p<0.001;r=0.0002,p<0.001;r=0.06,p<0.001;r=−0.07,p<0.001;and r=−0.37,p<0.001,respectively).Conclusions Vancomycin utilization was the predominant factor contributing to VRE_(fm)resistance;the effects of rural populations and the proportion of the population aged≥65 were significant but relatively minimal.Annual temperature and the number of beds in medical institutions per thousand people were protective factors against VRE_(fm).
文摘Background Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci （VRE） endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong. Methods We described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing （MLST） was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE. Results Between November 26 and December 17, 2011, 11 patients （1 exogenous case and 10 secondary cases） in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% （10/361）. There were 8 males and 3 females with a median age of 78 years （range, 40-87 years）. MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay （P 〈0.001）, a higher proportion with chronic cerebral and cardiopulmonary conditions （P=0.001）, underlying malignancies （P 〈0.001）, and presence of urinary catheter （P 〈0.001）, wound or ulcer （P 〈0.001）, and a greater proportion of these patients were receiving β-lactam/ β-1actamase inhibitors （P=0.009）, carbapenem group （P 〈0.001）, fluoroquinolones （P=0.003）, or vancomycin （P=0.001） when compared with the controls. Conclusion Extensive contact tracing and screening with a ＂search-and-confine＂ strategy was a successful tool for outbreak control in our healthcare reqion.
文摘Background:Vancomycin-resistant Enterococcus faecium ventriculitis is one of the most severe events in postneurosurgical intracranial infections.There are no guidelines recommending an appropriate treatment before.Case presentation:This case presents a successful linezolid treatment for post-neurosurgical vancomycin-resistant Enterococcus faecium ventriculitis of a 24-year-old man in the department of neurosurgery,Beijing Tiantan Hospital.Conclusions:Linezolid should be considered as one of the important methods for the treatment of postneurosurgical intracranial infections caused by vancomycin-resistant Enterococcus.
文摘Background The incidence of vancomycin-resistant enterococci （VRE） appeared to be increasing in China, but very few nosocomial outbreaks have been reported. Our hospital had experienced an outbreak of VRE since March 2008 to March 2009. The objective of this study was to analyze the molecular features of the isolates and the control measures used to eradicate a VRE outbreak in a tertiary institution in China.Methods We characterized VRE isolates from 21 infected and 11 colonized inpatients from a single hospital by pulsed field gel electrophoresis （PFGE）, multilocus sequence typing （MLST）, the analysis of Tn 1546-like elements and virulence genes detection. Infection control measures, including more environmental disinfection, screening for VRE colonization,contact precautions, education and strict antibiotic restriction, were implemented to control the outbreak.Results During the outbreak, a total of 32 VRE strains were obtained. There were 21 strains found in Emergency Intensive Care Unit （EICU）, 9 isolates from Geriatric Ward, and two from other units. All the isolates harbored the vanA gene, however,four of them exhibited the VanB phenotype. Meanwhile, MLST analysis revealed that all isolates belonged to clonal complex （CC） 17. With the infection-control measures, the epidemic was constrained in two units （EICU and Geriatric Ward）. After March 2009, no further case infected with VRE was detected in the following one-year period.Conclusion The outbreak was controlled by continuous implementation of the infection control programme, and more rigorous infection control policy is needed.
基金supported by the National Natural Science Foundation of China(32202200)Shanghai Excellent Academic/Technical Leaders Project(23XD1430500).
文摘This study provides different opinion for exploring the mechanism of catechin(CAT)relieving nonalcoholic steatohepatitis(NASH),it is more innovative to explore from the perspective of intestinal microorganism.Through in vitro fermentation experiments,CAT could improve the abundance of Enterococcus,and Enterococcus faecalis(EF)accounts for the vast majority of Enterococcus in human gut.The experimental results in vivo showed that EF group and CAT+EF group could reduce the body weight,liver index and epididymal fat index of NASH mice,and improve the changes of serum and liver indexes.Hematoxylin-eosin staining observation showed that these two groups have greatly improved the fatty degeneration,balloon degeneration and necrotic focus caused by NASH.The alleviation of CAT+EF group was more obvious.Results of targeted metabonomics showed that CAT could promote EF to produce more methyl palmitate(C_(16:0)),which plays a great role in relieving NASH.Our results indicated that EF could alleviate NASH and CAT+EF group had better alleviation may due to more production of methyl palmitate(C_(16:0))by EF.This study provides a new idea for CAT to alleviate NASH.
文摘The rough crystal of exopolysaccharide produced by Enterococcus durans, a strain of lactic acid bacteria screened from the intestine of a cock in our laboratory, was purified by CM-cellulose column chromatography, DEAE-Sephadex A-25 ionexchange and Sephadex G-100 gel chromatography to give EPS-Ⅰ. The EPS-Ⅰ was eluted as a single peak in HPLC analysis, indicating the homogeneity of EPS-Ⅰ and free from low-molecular-weight polysaccharides. The molecular weight of the EPS-Ⅰ was determined as 42 000 by the light scattering method. The result of its elemental analysis was C 41.08% and H 7.23% without the elements of N, P and S. Monosaccharide analysis showed that it was composed of Glc and Man in a molar ratio of 4∶1. Sugar composition analysis, methylation analysis and 1H and 13C NMR spectroscopy revealed that the EPS-Ⅰ was composed of pentasaccharide repeating units. The sequence of sugar residues was determined by using two-dimensional NMR, including heteronuclear multiple-bond correlation(HMBC) and nuclear overhauser effect spectroscopy(NOESY). The structure of the pentasaccharide repeating unit of EPS-Ⅰ was given, a new excellular polysaccharide from lactic acid bacterium compared with other EPSs was reported.
文摘FabB和FabF是大肠杆菌(Escherichia.coli)脂肪酸合成的关键酶.生物信息学分析显示,粪肠球菌基因组中有2个与大肠杆菌fabF同源的基因:fabF1和fabF2,缺少与fabB同源的基因.用粪肠球菌(Enterococcus faecalis)V583总DNA为模板,PCR扩增fabF1和fabF2基因,以pBAD24为载体,构建了重组质粒pHW13(fabF1)和pHW14(fabF2).体内体外研究显示:fabF1基因能互补大肠杆菌fabB突变,FabF1具有β酮脂酰ACP合成酶Ⅰ(FabB)活性;fabF2能互补大肠杆菌fabF突变,FabF2具有β酮脂酰ACP合成酶Ⅱ(FabF)活性.同时发现粪肠球菌FabF2不同于大肠杆菌FabF,它还拥有微弱β酮脂酰ACP合成酶Ⅰ(FabB)活性,可使大肠杆菌fabB突变株产生少量的不饱和脂肪酸.上述结果表明,FabF类酶(FabF like enzyme)同样可以具有β酮脂酰ACP合成酶Ⅰ(FabB)活性.
文摘Resistance against commonly used antibiotics is a serious clinical problem in recent medical practice. There exist several bacterial strains in which the possibilities of their inhibition are very limited due to multidrug resistance. Antimicrobial photodynamic therapy (aPDT) represents an option how to effectively suppress the growth of resistant pathogens. In this work we have studied interactions of potent photosensitizer hypericin (Hyp) with hospital-related gram positive (Gram+) and gram negative (Gram-) bacterial strains and the effects of photodynamic activated Hyp on bacterial susceptibility and/or resistance of these strains to antibiotics. We demonstrated a significant influence of photoactivated Hyp on growth of Staphylococcus aureus and Enterococcus sp. We have also shown that it is extremely important to use the effective concentrations of Hyp for aPDT, which completely inhibit the growth of microorganisms. Otherwise, there appears an increase in resistance, probably due to the activation of efflux mechanisms, which are involved in the efflux of Hyp and antibiotics as well.
基金Supported by The Polish Ministry of Science and Higher Education Grants No. 2 PO5A 094 29, 3 P05E 091 25, N N402 0861 and N N401 144638
文摘AIM: To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). METHODS: Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n =16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro. RESULTS: A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of theasa1 gene and thegelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain ofEnterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent amongEnterococcus strains isolated from children with IBD than in control strains. CONCLUSION: Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.
基金supported by the International Cooperation Program of Jiangsu Department of Science and Technology (BZ2011045)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD 2010-2013)the Health Promotion Project of Jiangsu Province (RC2007065 and RC2011071),China
文摘In the current study, we sought to investigate whether lysed Enterococcus faecalis FK-23 （LFK）, a heat-killed probiotic preparation, attenuated eosinophil influx into the upper airway and had immunomodulatory activity in a murine allergic rhinitis model. Eighteen BALB/c mice were divided into three groups; the ovalbumin （OVA）-sen- sitized/challenged group, which received saline orally for 6 weeks （OVA group）, the OVA-sensitized/challenged group, which received LFK orally for 6 weeks （LFK-fed group）, and the non-sensitized group, which received saline for 6 weeks （saline control group）. Nasal rubbing and sneezing were monitored during the study. After the final challenge, interleukin （IL）-4, interferon （IFN）-y, and OVA-specific IgE levels in the sera and splenocyte culture supernatants were determined, eosinophilic infiltrate into the upper airway was quantified, and splenic CD4~CD25＋ regulatory T cells （Tregs） were examined by flow cytometry. We found that nasal rubbing was sig- nificantly reduced in LFK-fed mice compared to the OVA group on d 27 and 35, and sneezing was significantly inhibited by LFK administration for 35 d. LFK-fed mice had significantly less eosinophil influx into the nasal mucosa than the OVA group. There were no significant differences between the LFK-fed group and OVA group in the serum and splenocyte culture supernatant levels of IL-4, IFN-y, and OVA-specific IgE. Interestingly, the LFK-fed mice had a significantly greater percentage of splenic CD4＋CD25＋ Tregs than OVA group. Our results indicate that oral administration of LFK may alleviate nasal symptoms, reduce nasal eosinophilia, and increase the percentage of CD4＋CD25＋ Tregs in experimental allergic rhinitis.
