The application of nanotechnology for antimicrobial delivery has capacity to improve anti-bacterial efficacy.Currently,the usage of various inorganic and organic carriers,such as metal ions,nano-silicon and surfactant...The application of nanotechnology for antimicrobial delivery has capacity to improve anti-bacterial efficacy.Currently,the usage of various inorganic and organic carriers,such as metal ions,nano-silicon and surfactants,might increase the potential toxicity of nanoparticles and make their clinical transformation more difficult.Herein,a nano-delivery system was constructed by direct self-assembly of antibacterial phytochemicals(berberine and rhein)originated from traditional Chinese medicine Coptis chinensis Franch.and Rheum palmatum L.,respectively.Combining X-ray single crystal diffraction,nuclear magnetic resonance and other spectra characterizations,the stacked structure of nanoparticles was profoundly demonstrated.Briefly,rhein acted as the layered backbone and berberine embedded in it.In vitro bacteriostasis experiment showed the minimum bactericidal concentration of nanoparticles was 0.1μmol/mL,which was lower than that of berberine and rhein.The results of confocal laser scanning microscope,biofilm quantitive assay and scanning electron microscopy indicated that nanoparticles had strong inhibitory effects on Staphylococcus aureus biofilm.More importantly,transmission electron microscopy and mass spectra indicated the further bacteriostatic mechanism of nanoparticles.Meanwhile,the nanoparticles had well biocompatibility and safety.Current study will open up new prospect that the design of self-assemblies between active phytochemicals can be originated from traditional Chinese medicine combination.展开更多
The inhibitory effects of three berberine alkaloids (BAs) from rhizome of Coptis chinensis Franch, a traditional Chinese medicinal (TCM) herb, on Staphylococcus aureus growth were investigated by mi- crocalorimetry. T...The inhibitory effects of three berberine alkaloids (BAs) from rhizome of Coptis chinensis Franch, a traditional Chinese medicinal (TCM) herb, on Staphylococcus aureus growth were investigated by mi- crocalorimetry. The power–time curves of S. aureus with and without BAs were acquired; meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by studying the growth rate constant (k), half inhibitory ratio (IC50), maximum heat-output power (Pmax), peak time of maximum heat-output power (tp) and total heat production (Qt). The value of k of S. aureus in the presence of the three BAs decreased with the increasing concentrations of BAs. Moreover, Pmax was reduced and the value of tp increased with increasing concentrations of the three drugs. The inhibitory activity varied with different drugs. The values of IC50 of the three BAs are respectively, 101.4 μg/mL for berberine, 241.0 μg/mL for palmatine and 792.3 μg/mL for jateorrhizine. The sequence of antimicrobial activity of the three BAs is: berberine > palmatine > jateorrhizine. It is suggested that the functional group me- thylenedioxy or methoxyl at C2 on the phenyl ring could possibly improve antimicrobial activity more strongly than hydroxyl at C2 on the phenyl ring.展开更多
Bacterial infections are a leading cause of morbidity and mortality among solid organ transplant recipients.Over the last two decades,various multidrug-resistant(MDR)pathogens have emerged as relevant causes of infect...Bacterial infections are a leading cause of morbidity and mortality among solid organ transplant recipients.Over the last two decades,various multidrug-resistant(MDR)pathogens have emerged as relevant causes of infection in this population.Although this fact reflects the spread of MDR pathogens in health care facilities worldwide,several factors relating to the care of transplant donor candidates and recipients render these patients particularly prone to the acquisition of MDR bacteria and increase the likelihood of MDR infectious outbreaks in transplant units.The awareness of this high vulnerability of transplant recipients to infection leads to the more frequent use of broad-spectrum empiric antibiotic therapy,which further contributes to the selection of drug resistance.This vicious cycle is difficult to avoid and leads to a scenario of increased complexity and narrowed therapeutic options.Infection by MDR pathogens is more frequently associated with a failure to start appropriate empiric antimicrobial ther-apy.The lack of appropriate treatment may contribute to the high mortality occurring in transplant recipients with MDR infections.Furthermore,high therapeutic failure rates have been observed in patients infected with extensively-resistant pathogens,such as carbapenemresistant Enterobacteriaceae,for which optimal treatment remains undefined.In such a context,the careful implementation of preventive strategies is of utmost importance to minimize the negative impact that MDR infections may have on the outcome of liver transplant recipients.This article reviews the current literature regarding the incidence and outcome of MDR infections in liver transplant recipients,and summarizes current preventive and therapeutic recommendations.展开更多
Background Previous studies have different viewpoints about the clinical impact of methicillin resistance on mortality of hospital-acquired bloodstream infection （BSI） patients with Staphylococcus aureus （S.aureus...Background Previous studies have different viewpoints about the clinical impact of methicillin resistance on mortality of hospital-acquired bloodstream infection （BSI） patients with Staphylococcus aureus （S.aureus）.The objective of this study was to investigate the mortality of hospital-acquired BSI with S.aureus in a military hospital and analyze the risk factors for the hospital mortality.Methods A retrospective cohort study was performed in patients admitted to the biggest military tertiary teaching hospital in China between January 2006 and May 2011.All included patients had clinically significant nosocomial BSI with S.aureus.Multivariate Logistic regression analysis was used to identify the risk factors for hospital mortality of patients with S.aureus BSI.Results One hundred and eighteen patients of more than one year old were identified as clinically and microbiologically confirmed nosocomial bacteraemia due to S.aureus,and 75 out of 118 patients were infected with methicillin-resistant S.aureus （MRSA）.The overall mortality of nosocomial S.aureus BSI was 28.0%.Methicillin resistance in S.aureus bacteremia was associated with significant increase in the length of hospitalization and high proportion of inappropriate empirical antibiotic treatment.After Logistic regression analysis,the severity of clinical manifestations （APACHE Ⅱ score） （odds ratio （OR） 1.22,95% confidence interval （CI） 1.12-1.34） and inadequacy of empirical antimicrobial therapy （OR 0.25,95% CI 0.09-0.69） remained as risk factors for hospital mortality.Conclusions Nosocomial S.aureus BSI was associated with high in-hospital mortality.Methicillin resistance in S.aureus has no significant impact on the outcome of patients with staphylococcal bacteremia.Proper empirical antimicrobial therapy is very important to the prognosis.展开更多
Background Staphylococcus aureus （S. aureus） remains as an important microbial pathogen resulting in community and nosocomial acquired infections with significant morbidity and mortality. Few reports for S. aureus i...Background Staphylococcus aureus （S. aureus） remains as an important microbial pathogen resulting in community and nosocomial acquired infections with significant morbidity and mortality. Few reports for S. aureus in lower respiratory tract infections （LRTIs） have been documented. The aim of this study was to explore the molecular epidemiology of S. aureus in LRTIs in China.Methods A multicenter study of the molecular epidemiology of S. aureus in LRTIs was conducted in 21 hospitals in Beijing, Shanghai and twelve other provinces from November 2007 to February 2009. All the collected S. aureus strains were classified as minimum inhibitory concentration （MIC）, mecA gene, virulence genes Panton-Valentine Leukocidin （PVL） and y-hemolysin （hlg）, staphylococcal cassette chromosome mec （SCCmec） type, agr type, and Multilocus Sequence Typinq （MLST）.Results Totally, nine methicillin-sensitive S. aureus （MSSA） and 29 methicillin-resistant S. aureus （MRSA） strains were isolated after culture from a total of 2829 sputums or bronchoalveolar lavages. The majority of MRSA strains （22/29） had a MIC value of 〉512 μg/ml for cefoxitin. The mecA gene acting as the conservative gene was carried by all MRSA strains. PVL genes were detected in only one S. aureus strain （2.63%, 1/38）. The hlg gene was detected in almost the all S. aureus （100% in MSSA and 96.56% in MRSA strains）. About 75.86% of MRSA strains carried SCCmec Ⅲ. Agr type 1 was predominant （78.95%） among the identified three agr types （agr types 1,2, and 3）. Totally, ten sequence type （ST） of S. aureus strains were detected. A new sequence type （ST1445） was found besides confirming ST239 as the major sequence type （60.53%）. A dendrogram generated from our own MLST database showed all the bootstrap values 〈50%. Conclusion Our preliminary epidemiology data show SCCmec Ⅲ, ST239 and agr type 1 of S. aureus as the predominant strains in LRTIs in Mainland of China.展开更多
The practice of phage therapy, which uses bacterial viruses(phages) to treat bacterial infections, has been around for almost a century. The universal decline in the effectiveness of antibiotics has generated renewed ...The practice of phage therapy, which uses bacterial viruses(phages) to treat bacterial infections, has been around for almost a century. The universal decline in the effectiveness of antibiotics has generated renewed interest in revisiting this practice. Conventionally, phage therapy relies on the use of naturally-occurring phages to infect and lyse bacteria at the site of infection. Biotechnological advances have further expanded the repertoire of potential phage therapeutics to include novel strategies using bioengineered phages and purified phage lytic proteins. Current research on the use of phages and their lytic proteins against multidrug-resistant bacterial infections, suggests phage therapy has the potential to be used as either an alternative or a supplement to antibiotic treatments. Antibacterial therapies, whether phage-or antibiotic-based, each have relative advantages and disadvantages; accordingly, many considerations must be taken into account when designing novel therapeutic approaches for preventing and treating bacterial infection. Although much about phages and human health is still being discovered, the time to take phage therapy serious again seems to be rapidly approaching.展开更多
Background Nosocomial infection caused by methicillin-resistant Staphylococcus aureus （MRSA） and vancomycin-resistant enterococci （VRE） could lead to increased morbidity and mortality. In 2006, VRE nosocomial spre...Background Nosocomial infection caused by methicillin-resistant Staphylococcus aureus （MRSA） and vancomycin-resistant enterococci （VRE） could lead to increased morbidity and mortality. In 2006, VRE nosocomial spread became a reality in our hospital since the first VRE nosocomial infection in 2003. Little is known about the prevalence of coexistence with VRE and MRSA in the patients. The primary objective of the study was to identify the molecular characteristics of epidemic MRSA clones in our hospital and the prevalence of the coexistence with MRSA and VRE in same patients during the 2-year period, 2006-2007. Methods The clinical features, laboratory test results, and therapeutic outcomes of 129 cases who isolated MRSA collected from January 2006 to December 2007 were retrospectively analyzed. Polymerase chain reaction （PCR） was used to determine mecA-femB type and staphylococcal cassette chromosome mec （SCCmec） type. All the participants were screened for clinical and microbiological data to identify the coexistence of VRE strains with MRSA. Results One hundred and twenty-nine MRSA isolates were included in the study： 71 （55%） from the intensive care unit, 35 （27.2%） from the surgical wards and 23 （17.8%） from the medical wards. The most frequent source of isolation of MRSA was sputum （76.7%）. From seven patients we isolated MRSA and VRE （E. faecium） simultaneously during their inpatient stay. One hundred and twenty-seven （127/129, 98.4%） MRSA isolates harboured SCCmec type Ⅲ, only 2 MRSA strains contained SCCmec type Ⅱ. All of the 129 MRSA isolates remained sensitive to vancomycin, teicoplanin and linezolid. Higher sensitivity rates were noted for chloramphenicol 99.2% （128/129）. Only 20.2% （26/129） of the MRSA isolates were sensitive to rifampin. All isolates presented resistance to multiple antimicrobial agents with high minimum inhibitory concentrations （MICs）, including： β-Iactams （penicillin, oxacillin, cefoxitin, and cefazolin）, tetracycline展开更多
基金funded by the Beijing Municipal Natural Science Foundation(No.7202116,China)National Natural Science Foundation of China(No.81603256)+2 种基金project of China Association of Chinese Medicine(CACM-2018-QNRC2-B08)the Fundamental Research Funds for the Central Universities(BUCM-2019-JCRC002,BUCM-2018-2020 and 2019-JYBTD005,China)Beijing Key Laboratory for Basic and Development Research on Chinese Medicine(Beijing,China)
文摘The application of nanotechnology for antimicrobial delivery has capacity to improve anti-bacterial efficacy.Currently,the usage of various inorganic and organic carriers,such as metal ions,nano-silicon and surfactants,might increase the potential toxicity of nanoparticles and make their clinical transformation more difficult.Herein,a nano-delivery system was constructed by direct self-assembly of antibacterial phytochemicals(berberine and rhein)originated from traditional Chinese medicine Coptis chinensis Franch.and Rheum palmatum L.,respectively.Combining X-ray single crystal diffraction,nuclear magnetic resonance and other spectra characterizations,the stacked structure of nanoparticles was profoundly demonstrated.Briefly,rhein acted as the layered backbone and berberine embedded in it.In vitro bacteriostasis experiment showed the minimum bactericidal concentration of nanoparticles was 0.1μmol/mL,which was lower than that of berberine and rhein.The results of confocal laser scanning microscope,biofilm quantitive assay and scanning electron microscopy indicated that nanoparticles had strong inhibitory effects on Staphylococcus aureus biofilm.More importantly,transmission electron microscopy and mass spectra indicated the further bacteriostatic mechanism of nanoparticles.Meanwhile,the nanoparticles had well biocompatibility and safety.Current study will open up new prospect that the design of self-assemblies between active phytochemicals can be originated from traditional Chinese medicine combination.
基金Supported by the National Natural Science Foundation of China (Grant No. 30625042)
文摘The inhibitory effects of three berberine alkaloids (BAs) from rhizome of Coptis chinensis Franch, a traditional Chinese medicinal (TCM) herb, on Staphylococcus aureus growth were investigated by mi- crocalorimetry. The power–time curves of S. aureus with and without BAs were acquired; meanwhile the extent and duration of inhibitory effects on the metabolism were evaluated by studying the growth rate constant (k), half inhibitory ratio (IC50), maximum heat-output power (Pmax), peak time of maximum heat-output power (tp) and total heat production (Qt). The value of k of S. aureus in the presence of the three BAs decreased with the increasing concentrations of BAs. Moreover, Pmax was reduced and the value of tp increased with increasing concentrations of the three drugs. The inhibitory activity varied with different drugs. The values of IC50 of the three BAs are respectively, 101.4 μg/mL for berberine, 241.0 μg/mL for palmatine and 792.3 μg/mL for jateorrhizine. The sequence of antimicrobial activity of the three BAs is: berberine > palmatine > jateorrhizine. It is suggested that the functional group me- thylenedioxy or methoxyl at C2 on the phenyl ring could possibly improve antimicrobial activity more strongly than hydroxyl at C2 on the phenyl ring.
文摘Bacterial infections are a leading cause of morbidity and mortality among solid organ transplant recipients.Over the last two decades,various multidrug-resistant(MDR)pathogens have emerged as relevant causes of infection in this population.Although this fact reflects the spread of MDR pathogens in health care facilities worldwide,several factors relating to the care of transplant donor candidates and recipients render these patients particularly prone to the acquisition of MDR bacteria and increase the likelihood of MDR infectious outbreaks in transplant units.The awareness of this high vulnerability of transplant recipients to infection leads to the more frequent use of broad-spectrum empiric antibiotic therapy,which further contributes to the selection of drug resistance.This vicious cycle is difficult to avoid and leads to a scenario of increased complexity and narrowed therapeutic options.Infection by MDR pathogens is more frequently associated with a failure to start appropriate empiric antimicrobial ther-apy.The lack of appropriate treatment may contribute to the high mortality occurring in transplant recipients with MDR infections.Furthermore,high therapeutic failure rates have been observed in patients infected with extensively-resistant pathogens,such as carbapenemresistant Enterobacteriaceae,for which optimal treatment remains undefined.In such a context,the careful implementation of preventive strategies is of utmost importance to minimize the negative impact that MDR infections may have on the outcome of liver transplant recipients.This article reviews the current literature regarding the incidence and outcome of MDR infections in liver transplant recipients,and summarizes current preventive and therapeutic recommendations.
文摘Background Previous studies have different viewpoints about the clinical impact of methicillin resistance on mortality of hospital-acquired bloodstream infection （BSI） patients with Staphylococcus aureus （S.aureus）.The objective of this study was to investigate the mortality of hospital-acquired BSI with S.aureus in a military hospital and analyze the risk factors for the hospital mortality.Methods A retrospective cohort study was performed in patients admitted to the biggest military tertiary teaching hospital in China between January 2006 and May 2011.All included patients had clinically significant nosocomial BSI with S.aureus.Multivariate Logistic regression analysis was used to identify the risk factors for hospital mortality of patients with S.aureus BSI.Results One hundred and eighteen patients of more than one year old were identified as clinically and microbiologically confirmed nosocomial bacteraemia due to S.aureus,and 75 out of 118 patients were infected with methicillin-resistant S.aureus （MRSA）.The overall mortality of nosocomial S.aureus BSI was 28.0%.Methicillin resistance in S.aureus bacteremia was associated with significant increase in the length of hospitalization and high proportion of inappropriate empirical antibiotic treatment.After Logistic regression analysis,the severity of clinical manifestations （APACHE Ⅱ score） （odds ratio （OR） 1.22,95% confidence interval （CI） 1.12-1.34） and inadequacy of empirical antimicrobial therapy （OR 0.25,95% CI 0.09-0.69） remained as risk factors for hospital mortality.Conclusions Nosocomial S.aureus BSI was associated with high in-hospital mortality.Methicillin resistance in S.aureus has no significant impact on the outcome of patients with staphylococcal bacteremia.Proper empirical antimicrobial therapy is very important to the prognosis.
文摘Background Staphylococcus aureus （S. aureus） remains as an important microbial pathogen resulting in community and nosocomial acquired infections with significant morbidity and mortality. Few reports for S. aureus in lower respiratory tract infections （LRTIs） have been documented. The aim of this study was to explore the molecular epidemiology of S. aureus in LRTIs in China.Methods A multicenter study of the molecular epidemiology of S. aureus in LRTIs was conducted in 21 hospitals in Beijing, Shanghai and twelve other provinces from November 2007 to February 2009. All the collected S. aureus strains were classified as minimum inhibitory concentration （MIC）, mecA gene, virulence genes Panton-Valentine Leukocidin （PVL） and y-hemolysin （hlg）, staphylococcal cassette chromosome mec （SCCmec） type, agr type, and Multilocus Sequence Typinq （MLST）.Results Totally, nine methicillin-sensitive S. aureus （MSSA） and 29 methicillin-resistant S. aureus （MRSA） strains were isolated after culture from a total of 2829 sputums or bronchoalveolar lavages. The majority of MRSA strains （22/29） had a MIC value of 〉512 μg/ml for cefoxitin. The mecA gene acting as the conservative gene was carried by all MRSA strains. PVL genes were detected in only one S. aureus strain （2.63%, 1/38）. The hlg gene was detected in almost the all S. aureus （100% in MSSA and 96.56% in MRSA strains）. About 75.86% of MRSA strains carried SCCmec Ⅲ. Agr type 1 was predominant （78.95%） among the identified three agr types （agr types 1,2, and 3）. Totally, ten sequence type （ST） of S. aureus strains were detected. A new sequence type （ST1445） was found besides confirming ST239 as the major sequence type （60.53%）. A dendrogram generated from our own MLST database showed all the bootstrap values 〈50%. Conclusion Our preliminary epidemiology data show SCCmec Ⅲ, ST239 and agr type 1 of S. aureus as the predominant strains in LRTIs in Mainland of China.
基金Supported by Winkler Bacterial Overgrowth Research Fund(in part)
文摘The practice of phage therapy, which uses bacterial viruses(phages) to treat bacterial infections, has been around for almost a century. The universal decline in the effectiveness of antibiotics has generated renewed interest in revisiting this practice. Conventionally, phage therapy relies on the use of naturally-occurring phages to infect and lyse bacteria at the site of infection. Biotechnological advances have further expanded the repertoire of potential phage therapeutics to include novel strategies using bioengineered phages and purified phage lytic proteins. Current research on the use of phages and their lytic proteins against multidrug-resistant bacterial infections, suggests phage therapy has the potential to be used as either an alternative or a supplement to antibiotic treatments. Antibacterial therapies, whether phage-or antibiotic-based, each have relative advantages and disadvantages; accordingly, many considerations must be taken into account when designing novel therapeutic approaches for preventing and treating bacterial infection. Although much about phages and human health is still being discovered, the time to take phage therapy serious again seems to be rapidly approaching.
基金The study was supported by-grants from the National Natural Science Foundation of China （No. 30870094/C010603） and the Beijing Science ＆ Technology （No. Z08050700020801）.
文摘Background Nosocomial infection caused by methicillin-resistant Staphylococcus aureus （MRSA） and vancomycin-resistant enterococci （VRE） could lead to increased morbidity and mortality. In 2006, VRE nosocomial spread became a reality in our hospital since the first VRE nosocomial infection in 2003. Little is known about the prevalence of coexistence with VRE and MRSA in the patients. The primary objective of the study was to identify the molecular characteristics of epidemic MRSA clones in our hospital and the prevalence of the coexistence with MRSA and VRE in same patients during the 2-year period, 2006-2007. Methods The clinical features, laboratory test results, and therapeutic outcomes of 129 cases who isolated MRSA collected from January 2006 to December 2007 were retrospectively analyzed. Polymerase chain reaction （PCR） was used to determine mecA-femB type and staphylococcal cassette chromosome mec （SCCmec） type. All the participants were screened for clinical and microbiological data to identify the coexistence of VRE strains with MRSA. Results One hundred and twenty-nine MRSA isolates were included in the study： 71 （55%） from the intensive care unit, 35 （27.2%） from the surgical wards and 23 （17.8%） from the medical wards. The most frequent source of isolation of MRSA was sputum （76.7%）. From seven patients we isolated MRSA and VRE （E. faecium） simultaneously during their inpatient stay. One hundred and twenty-seven （127/129, 98.4%） MRSA isolates harboured SCCmec type Ⅲ, only 2 MRSA strains contained SCCmec type Ⅱ. All of the 129 MRSA isolates remained sensitive to vancomycin, teicoplanin and linezolid. Higher sensitivity rates were noted for chloramphenicol 99.2% （128/129）. Only 20.2% （26/129） of the MRSA isolates were sensitive to rifampin. All isolates presented resistance to multiple antimicrobial agents with high minimum inhibitory concentrations （MICs）, including： β-Iactams （penicillin, oxacillin, cefoxitin, and cefazolin）, tetracycline
