Background： Aerosolized amikacin （AA） is a current option for the management of ventilator-associated pneumonia （VAP） caused by multidrug-resistant Gram-negative bacteria （MDR-GNB）, as it is reported that AA co...Background： Aerosolized amikacin （AA） is a current option for the management of ventilator-associated pneumonia （VAP） caused by multidrug-resistant Gram-negative bacteria （MDR-GNB）, as it is reported that AA could increase the alveolar level of the drug without increasing systemic toxicity. This study aimed to evaluate the efficacy and safety of AA as an adjunctive therapy for VAP caused by MDR-GNB. Methods： In this single-center, double-blind study conducted in a 36-bed general Intensive Care Unit （ICU） in a tertiary hospital from June 2014 to June 2016, 52 ICU patients with confirmed MDR-GNB VAP were randomized to two groups （AA group, n - 27 and placebo group, n = 25）. Amikacin （400 rag, q8h） or saline placebo （4 ml, q8h） was aerosolized for 7 days. The attending physician determined the administration of systemic antibiotics for VAP. Patients were tbllowed up for 28 days. Bacteriological eradication, clinical pulmonary infection score （CP1S）, and serum creatinine were assessed on day 7 of therapy. New resistance to amikacin, cure rate of VAP, weaning rate, and mortality were assessed on day 28. Results： The baseline characteristics of patients in both groups were similar. At the end of the treatment, 13 of the 32 initially detected bacterial isolates were eradicated in AA group, compared to 4 of 28 in placebo group （41% vs. 14%, P - 0.024）. As for patients, 11 of 27 patients treated with AA and 4 of 25 patients treated with placebo have eradication （41% vs. 16%, P = 0.049）. The adjunction of AA reduced CPIS （4.2 ± 1.6 vs. 5.8 ± 2.1, P = 0.007）. New drug resistance to amikacin and the change in serum creatinine were not detected in AA group. No significant differences in the clinical cure rate in survivors （48% vs. 35%, P = 0.444）, weaning rate （48% vs. 32%, P = 0.236）, and mortality （22% vs. 32%, P = 0.427） were detected between the two groups on day 28. Conclusions： As an adjunctive therapy of MDR-GNB VAP, AA successfully eradicated existing M展开更多
Decomposition of soil organic matter(SOM) is of importance for CO_2 exchange between soil and atmosphere and soil temperature and moisture are considered as two important factors controlling SOM decomposition. In this...Decomposition of soil organic matter(SOM) is of importance for CO_2 exchange between soil and atmosphere and soil temperature and moisture are considered as two important factors controlling SOM decomposition. In this study, soil samples were collected at 5 elevations ranging from 753 to 2 357 m on the Changbai Mountains in Northeast China, and incubated under different temperatures(5, 10, 15, 20, 25, and 30?C) and soil moisture levels(30%, 60%, and 90% of saturated soil moisture) to investigate the effects of both on SOM decomposition and its temperature sensitivity at different elevations. The results showed that incubation temperature(F = 1 425.10, P < 0.001), soil moisture(F = 1 327.65, P < 0.001), and elevation(F = 1 937.54, P < 0.001) all had significant influences on the decomposition rate of SOM. The significant effect of the interaction of incubation temperature and soil moisture on the SOM decomposition rate was observed at all the 5 sampling elevations(P < 0.001). A two-factor model that used temperature and moisture as variables fitted the SOM decomposition rate well(P < 0.001) and could explain 80%–93% of the variation of SOM decomposition rate at the 5 elevations. Temperature sensitivity of SOM decomposition, expressed as the change of SOM decomposition rate in response to a 10?C increase in temperature(Q_(10)), was significantly different among the different elevations(P < 0.01), but no apparent trend with elevation was discernible. In addition, soil moisture and incubation temperature both had great impacts on the Q_(10) value(P < 0.01), which increased significantly with increasing soil moisture or incubation temperature. Furthermore, the SOM decomposition rate was significantly related to soil total Gram-positive bacteria(R^2= 0.33, P < 0.01) and total Gram-negative bacteria(R^2= 0.58, P < 0.001). These findings highlight the importance of soil moisture to SOM decomposition and its Q_(10) value,which needs to be emphasized under warming climate scenarios.展开更多
The responses of soil microbes to global warming and nitrogen enrichment can profoundly affect terrestrial ecosystem functions and the ecosystem feedbacks to climate change.However,the interactive effect of warming an...The responses of soil microbes to global warming and nitrogen enrichment can profoundly affect terrestrial ecosystem functions and the ecosystem feedbacks to climate change.However,the interactive effect of warming and nitrogen enrichment on soil microbial community is unclear.In this study,individual and interactive effects of experimental warming and nitrogen addition on the soil microbial community were investigated in a long-term field experiment in a temperate steppe of northern China.The field experiment started in 2006 and soils were sampled in 2010 and analyzed for phospholipid fatty acids to characterize the soil microbial communities.Some soil chemical properties were also determined.Five-year experimental warming significantly increased soil total microbial biomass and the proportion of Gram-negative bacteria in the soils.Long-term nitrogen addition decreased soil microbial biomass at the 0-10 cm soil depth and the relative abundance of arbuscular mycorrhizal fungi in the soils.Little interactive effect on soil microbes was detected when experimental warming and nitrogen addition were combined.Soil microbial biomass positively correlated with soil total C and N,but basically did not relate to the soil C/N ratio and pH.Our results suggest that future global warming or nitrogen enrichment may significantly change the soil microbial communities in the temperate steppes in northern China.展开更多
Bacterial infection in the first month after liver transplantation is a frequent complication that poses a serious risk for liver transplant recipients as contributes substantially to increased length of hospitalizati...Bacterial infection in the first month after liver transplantation is a frequent complication that poses a serious risk for liver transplant recipients as contributes substantially to increased length of hospitalization and hospital costs being a leading cause of death in this period. Most of these infections are caused by gramnegative bacilli, although gram-positive infections, especially Enterococcus sp. constitute an emerging infectious problem. This high rate of early postoperative infections after liver transplant has generated interest in exploring various prophylactic approaches to surmount this problem. One of these approaches is selective intestinal decontamination(SID). SID is a prophylactic strategy that consists of the administration of antimicrobials with limited anaerobicidal activity in order to reduce the burden of aerobic gram-negative bacteria and/or yeast in the intestinal tract and so prevent infections caused by these organisms. The majority of studies carried out to date have found SID to be effective in the reduction of gram-negative infection, but the effect on overall infection is limited due to a higher number of infection episodes by pathogenic enterococci and coagulase-negative staphylococci. However, difficulties in general extrapolation of the favorable results obtained in specific studies together with the potential risk of selection of multirresistant microorganisms has conditioned controversy about the routinely application of these strategies in liver transplant recipients.展开更多
Objective： To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressin...Objective： To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressing multidrug resistant （MDR） phenotypes. Methods： The antimicrobial activity of the extracts was performed using the broth microdilution method. The phytochemical screening of these extracts was also performed using standard methods. Resalts： Ocimum basilicum, Gnetum africanum and Eucalyptus robusta extracts possessed an antibacterial activity against all the 29 studied bacteria. The extracts from G. africanum and E. robusta were the most active with the lowest minimal inhibitory concentration of 64 p, g/mL on Escherichia coil AG100A for both extracts and also against Klebsiella pneumoniae K24 for G. africanum. When tested in the presence of phenylalanine-arginine 13 -Naphtylamide （PA 13 N）, an efflux pump inhibitor, the extract of Thymus vulgafis and E. Robusta showed the best activities on most tested strains. E. Robusta extract showed good synergistic effects, improving the activity of commonly used antibiotics in about 85% of cases. Coaclasion： The overall results obtained provide the baseline information for the use of the tested plants in the treatment of bacterial infections.展开更多
Pharmaceutical wastewater treatment plants（WWTPs） are thought to be a ＂seedbed＂ and reservoirs for multi-antibiotic resistant pathogenic bacteria which can be transmitted to the air environment through aeration. W...Pharmaceutical wastewater treatment plants（WWTPs） are thought to be a ＂seedbed＂ and reservoirs for multi-antibiotic resistant pathogenic bacteria which can be transmitted to the air environment through aeration. We quantified airborne multi-antibiotic resistance in a full-scale plant to treat antibiotics-producing wastewater by collecting bioaerosol samples from December2014 to July 2015. Gram-negative opportunistic pathogenic bacteria（GNOPB） were isolated, and antibiotic susceptibility tests against 18 commonly used antibiotics, including 11 β-lactam antibiotics, 3 aminoglycosides, 2 fluoroquinolones, 1 furan and 1 sulfonamide, were conducted.More than 45% of airborne bacteria isolated from the pharmaceutical WWTP were resistant to three or more antibiotics, and some opportunistic pathogenic strains were resistant to 16 antibiotics, whereas 45.3% and 50.3% of the strains isolated from residential community and municipal WWTP showed resistance to three or more antibiotics. The calculation of the multiple antibiotic resistance（MAR） index demonstrated that the air environment in the pharmaceutical WWTP was highly impacted by antibiotic resistance, while the residential community and municipal WWTP was less impacted by antibiotic resistance. In addition, we determined that the dominant genera of opportunistic pathogenic bacteria isolated from all bioaerosol samples were Acinetobacter, Alcaligenes, Citrobacter, Enterobacter, Escherichia, Klebsiella, Pantoea, Pseudomonas and Sphingomonas. Collectively, these results indicate the proliferations and spread of antibiotic resistance through bioaerosols in WWTP treating cephalosporin-producing wastewater, which imposed a potential health risk for the staff and residents in the neighborhood, calling for administrative measures to minimize the air-transmission hazard.展开更多
BACKGROUND Diabetic foot ulceration(DFU)is the prime health concern globally.It accounts for the major burden related to disease mortality and morbidity and economic cost.The timely and early recognition of the DFU ca...BACKGROUND Diabetic foot ulceration(DFU)is the prime health concern globally.It accounts for the major burden related to disease mortality and morbidity and economic cost.The timely and early recognition of the DFU can help present its occurrence and improve clinical outcomes.AIM To evaluate interrelationships between foot ulcers,risk factors,and antibiotic resistance among diabetic patients having ulcers in their foot.METHODS The databases such as PubMed,ERIC,Medline,and Google Scholar were extensively used for the extraction of studies.The selected studies were published within the time-period of 2014-2018.Ten studies were selected,which were found to be completely relevant to the current study.RESULTS The prevalence of diabetic foot ulcers among the population was evaluated,and the associated risk factors with its prevalence.Moreover,few studies also reported on the bacteria that are found to be most prevailing among diabetic patients.A narrative discussion was drawn through this analysis,which was used to highlight the specific area of research through selected studies,extraction of the significant information that matched with the topic of research,and analysis of problem through the findings of the selected articles.The results helped in assessing significant knowledge regarding the risk factors of diabetic foot ulcers and the role of antimicrobial resistant in its treatment.CONCLUSION The gram-negative bacteria were found to be the most common reason for diabetic foot ulcers.The study only included 10 studies that are not sufficient to produce generalized results,and no information was reported on the tests required to analyze antimicrobial susceptibility that can guide clinicians to propose better and sound treatment plans.It is evident that most study results depicted that the most common risk factors were found to be hypertension and neuropathy.展开更多
INTRODUCTIONAcute narcotizing pancreatitis usually takes a severe clinical course and is associated with multiple organ dysfunction .With the further understanding of pathophysiological events of acute pancreatisis an...INTRODUCTIONAcute narcotizing pancreatitis usually takes a severe clinical course and is associated with multiple organ dysfunction .With the further understanding of pathophysiological events of acute pancreatisis and the therapeutic measuses taken by the clinicians ,the patients can pass through the critical carry stages ,and then the septic complication caused by rtanslocated bacteria, mostly gram-negative microbes from the intestines ensues[1].展开更多
Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for...Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.展开更多
The use of antibiotics in humans and animals has been marked as a significant step in health due to their effectiveness in controlling and treating bacterial infections. The misuse and overuse of antibiotics have been...The use of antibiotics in humans and animals has been marked as a significant step in health due to their effectiveness in controlling and treating bacterial infections. The misuse and overuse of antibiotics have been identified as risk factors for bacterial resistance since microorganisms adapt and develop mechanisms to defend against antibiotics. According to the Centers for Disease Protection and Control (CDC), around 23,000 individuals die every year in the United States due to antibiotic resistance complications. As a result, a demand for alternative treatments has been a goal for scientists as the microbes adapt to selective pressure. The aim of this study is to test the antibacterial activity of leaf extracts of Peganum harmala and Haloxylon salicornicum on both Gram-positive and Gram-negative bacteria on various mediums. The results of the study showed that both P. harmala and H. salicornicum inhibited the bacterial growth in two different media. The results were also compared with different common antibiotics used in both human’s and animal’s fields and showed a promising outcome as alternative antibiotics.展开更多
目的评价基质辅助激光解吸电离飞行时间质谱（matrix assisted laser desorption ionisation time of flight mass spectrometry, MALDI-TOF-MS）技术检测临床常见革兰阴性杆菌的临床应用价值。方法1665株革兰阴性杆菌经VITEK2Compact...目的评价基质辅助激光解吸电离飞行时间质谱（matrix assisted laser desorption ionisation time of flight mass spectrometry, MALDI-TOF-MS）技术检测临床常见革兰阴性杆菌的临床应用价值。方法1665株革兰阴性杆菌经VITEK2Compact鉴定到属和种，采用MALDI—TOF—MS对1665株革兰阴性杆菌进行种属检测，并计算鉴定正确率。结果1665株菌包括27个菌属，73个菌种。主要革兰阴性杆菌菌属鉴定整体正确率为95．7％，菌种整体正确率为85．5％。其中菌属鉴定正确率最高的是布鲁菌属和沙门菌属，正确率均为100．0％；菌种鉴定正确率最高的为危险罗尔斯顿菌和摩氏摩根菌，正确率均为100．0％。结论MALDI—TOF—MS技术鉴定细菌快速、准确、方便，且成本低，适用于临床实验室的快速鉴定诊断。展开更多
Antimicrobial proteins and peptides had been found from a wide variety of organisms in the last few years These molecules have attracted much research interest because of their biochemical diversity, broad specificity...Antimicrobial proteins and peptides had been found from a wide variety of organisms in the last few years These molecules have attracted much research interest because of their biochemical diversity, broad specificity on anti-viral, anti-bacterial, anti-fungi, anti-protozoan parasites, anti-tumoural, and wound-healing effects. Antimicrobial proteins and peptides play key roles in innate immunity. They interact directly with bacteria and kill them. The brown-spotted grouper, Epinephelusfario, is an important marine fish cultured in southem China. Recently, bacteria and virus have caused high mortality in E. fario cultures, but its endogenous antimicrobial peptides and proteins have not been explored. An antimicrobial component was found from the skin homogenate of E. fario. After the skin homogenate was digested with trypsin, its antimicrobial activity was lost, which showed that the antimicrobial component is a protein. The antimicrobial protein （Efap） was purified from the skin homogenate of E. fario by successive ion-exchange and gel filtration chromatography. Efap was demonstrated to be single protein band by SDS-PAGE, with the apparent molecular weight of 41 kD. Efap exhibited antimicrobial activity both for the Gram-positive bacteria, Staphylococcus aureus, Micrococcus luteus and Bacillus subtilis, and for the Gram-negative bacteria, Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio fluvialis, Pasteurella multocida, Aeromonas hydrophila, Eschrrichiu coli, and Pseudomonas aeruginosa. Except A. hydrophila, P. aeruginosa, and E. coli （MIC〉20 mol/L）, most of the tested Gram-negative bacteria were sensitive to Efap （MIC〈20 mol/L）. Interestingly, Efap showed potent antimicrobial activity against Gram-positive bacteria S. aureus （MIC 5-10 mol/L） but comparatively weak antimicrobial activity against M. luteus and B. subtilis. The broad antimicrobial activities of Efap suggest that it contributes to the innate host defence of E. fario.展开更多
Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insig...Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.展开更多
Background:Acute suppurative terminal cholangitis(ASTC)is rarer than acute obstructive cholangitis and is not well studied.To explore this subtype of acute cholangitis,we described our clinical experience with ASTC.Me...Background:Acute suppurative terminal cholangitis(ASTC)is rarer than acute obstructive cholangitis and is not well studied.To explore this subtype of acute cholangitis,we described our clinical experience with ASTC.Methods:We performed a retrospective review of patients with ASTC admitted to our center from September 2014 to August 2020.We analyzed their clinical characteristics,including etiology,clinical manifestations,imaging features,treatment and prognosis.Results:A total of 32 ASTC patients were included in the analysis.The majority of the patients had a history of biliary operations,and clinical manifestations were occult and atypical.The positive rate of bacterial culture was 46.9%.All the patients had typical imaging features on computed tomography and magnetic resonance imaging.Treatment with effective antibiotics was provided as soon as diagnosis was established.After treatment,most patients had a good outcome.Elevated levels of total bilirubin,aspartate aminotransferase,procalcitonin and gamma-glutamyltransferase were the characteristics of critically ill patients and were associated with relatively poor prognosis.Conclusions:Our results demonstrated that ASTC should be recognized as a new subtype of acute cholangitis,and that earlier diagnosis and more personalized treatments are needed.展开更多
BACKGROUND Immunosuppression is an important factor in the incidence of infections in transplant recipient.Few studies are available on the management of immunosuppression(IS)treatment in the liver transplant(LT)recip...BACKGROUND Immunosuppression is an important factor in the incidence of infections in transplant recipient.Few studies are available on the management of immunosuppression(IS)treatment in the liver transplant(LT)recipients complicated with infection.The aim of this study is to describe our experience in the management of IS treatment during bacterial bloodstream infection(BSI)in LT recipients and assess the effect of temporary IS withdrawal on 30 d mortality of recipients presenting with severe infection.AIM To assess the effect of temporary IS withdrawal on 30 d mortality of LT recipients presenting with severe infection.METHODS A retrospective study was conducted with patients diagnosed with BSI after LT in the Department of Liver Surgery,Renji Hospital from January 1,2016 through December 31,2017.All recipients diagnosed with BSI after LT were included.Univariate and multivariate Cox regression analysis of risk factors for 30 d mortality was conducted in the LT recipients with Gram-negative bacterial(GNB)infection.RESULTS Seventy-four episodes of BSI were identified in 70 LT recipients,including 45 episodes of Gram-positive bacterial(GPB)infections in 42 patients and 29 episodes of GNB infections in 28 patients.Overall,IS reduction(at least 50%dose reduction or cessation of one or more immunosuppressive agent)was made in 28(41.2%)cases,specifically,in 5(11.9%)cases with GPB infections and 23(82.1%)cases with GNB infections.The 180 d all-cause mortality rate was 18.5%(13/70).The mortality rate in GNB group(39.3%,11/28)was significantly higher than that in GPB group(4.8%,2/42)(P=0.001).All the deaths in GNB group were attributed to worsening infection secondary to IS withdrawal,but the deaths in GPB group were all due to graft-versus-host disease.GNB group was associated with significantly higher incidence of intra-abdominal infection,IS reduction,and complete IS withdrawal than GPB group(P<0.05).Cox regression showed that rejection(adjusted hazard ratio 7.021,P=0.001)and complete IS withdrawal(adjusted hazard r展开更多
OBJECTIVE： To evaluate the antibacterial activity of the combination of different honey brands and methanolic fraction of Herba Ocimi Basilici using agar well diffusion assay. METHODS： The antibacterial activity was...OBJECTIVE： To evaluate the antibacterial activity of the combination of different honey brands and methanolic fraction of Herba Ocimi Basilici using agar well diffusion assay. METHODS： The antibacterial activity was deter- mined against thirteen pathogenic bacterial clini- cal isolates including six gram negative （Klebsiella pneumonia, Pseudomonas aeroginosa, Escherichia coli, Salmonella typhi, Salmonella typhimirium, Xanthomonas campestris） and six gram positive strains （Enterococcus faecalis faecalis, Bacillus subti- lis, Staphylococcus aureus, Clostridium perfringens type C, Clostridium perfringens type D, CIostridium chauvoei）. Agar well diffusion method was used while zones of inhibition were measured with verni- er scale. RESULTS： At higher concentration, all the honey brands showed good to significant activity. Thehighest activity was observed for Hamdard brand honey （27.60±0.40） against Enterococcus faecalis. CONCLUSION： These results revealed that combi- nations of plant extracts of Herba Ocimi Basilici with honey can be used for the development of potent and novel antibacterial agents.展开更多
The incidence of gram-negative multidrug-resistant(MDR) bacterial pathogens is increasing in hospitals and particularly in the intensive care unit(ICU) setting. The clinical consequences of infections caused by MDR pa...The incidence of gram-negative multidrug-resistant(MDR) bacterial pathogens is increasing in hospitals and particularly in the intensive care unit(ICU) setting. The clinical consequences of infections caused by MDR pathogens remain controversial. The purpose of this review is to summarize the available data concerning the impact of these infections on mortality in ICU patients. Twenty-four studies, conducted exclusively in ICU patients, were identified through Pub Med search over the years 2000-2015. Bloodstream infection was the only infection examined in eight studies, respiratory infections in four and variable infections in others. Comparative data on the appropriateness of empirical antibiotic treatment were provided by only seven studies. In ten studies the presence of antimicrobial resistance was not associated with increased mortality; on the contrary, in other studies a significant impact of antibiotic resistance on mortality was found, though, sometimes, mediated by inappropriate antimicrobial treatment. Therefore, a direct association between infections due to gram-negative MDR bacteria and mortality in ICU patients cannot be confirmed. Sample size, presence of multiple confounders and other methodological issues may influence the results. These data support the need for further studies to elucidate the real impact of infections caused by resistant bacteria in ICU patients.展开更多
The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoaceti...The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also provide an effective synthesis method for preparing functional bioconjugated nanoparticles here.展开更多
Alzheimer's disease(AD)is the most serious age-related neurodegenerative disease and causes destructive and irreversible cognitive decline.Failures in the development of therapeutics targeting amyloid-β(Aβ)and t...Alzheimer's disease(AD)is the most serious age-related neurodegenerative disease and causes destructive and irreversible cognitive decline.Failures in the development of therapeutics targeting amyloid-β(Aβ)and tau;principal proteins inducing pathology in AD,suggest a paradigm shift towards the development of new therapeutic targets.The gram-negative bacteria and lipopolysaccharides(LPS)are attractive new targets for AD treatment.Surprisingly,an altered distribution of gram-negative bacteria and their LPS has been reported in AD patients.Moreover,gram-negative bacteria and their LPS have been shown to affect a variety of AD-related pathologies,such as Aβ homeostasis,tau pathology,neuroinflammation,and neurodegeneration.Moreover,therapeutic approaches targeting gram-negative bacteria or gram-negative bacterial molecules have significantly alleviated AD-related pathology and cognitive dysfunction.Despite multiple evidence showing that the gram-negative bacteria and their LPS play a crucial role in AD pathogenesis,the pathogenic mechanisms of gram-negative bacteria and their LPS have not been clarified.Here,we summarize the roles and pathomechanisms of gram-negative bacteria and LPS in AD.Furthermore,we discuss the possibility of using gram-negative bacteria and gram-negative bacterial molecules as novel therapeutic targets and new pathological characteristics for AD.展开更多
Tigecycline serves as a critical“final-resort”antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited.The increasing prevalence of tigecyc...Tigecycline serves as a critical“final-resort”antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited.The increasing prevalence of tigecycline resistance,particularly among Gram-negative bacteria,is a major concern.Various mechanisms have been iden-tified as contributors to tigecycline resistance,including upregulation of nonspecific Resistance Nodulation Divi-sion(RND)efflux pumps due to mutations in transcriptional regulators,enzymatic modification of tigecycline by monooxygenase enzymes,and mutations affecting tigecycline binding sites.This review aims to consolidate our understanding of tigecycline resistance mechanisms in Gram-negative bacteria and offer insights and perspectives for further drug development.展开更多
文摘Background： Aerosolized amikacin （AA） is a current option for the management of ventilator-associated pneumonia （VAP） caused by multidrug-resistant Gram-negative bacteria （MDR-GNB）, as it is reported that AA could increase the alveolar level of the drug without increasing systemic toxicity. This study aimed to evaluate the efficacy and safety of AA as an adjunctive therapy for VAP caused by MDR-GNB. Methods： In this single-center, double-blind study conducted in a 36-bed general Intensive Care Unit （ICU） in a tertiary hospital from June 2014 to June 2016, 52 ICU patients with confirmed MDR-GNB VAP were randomized to two groups （AA group, n - 27 and placebo group, n = 25）. Amikacin （400 rag, q8h） or saline placebo （4 ml, q8h） was aerosolized for 7 days. The attending physician determined the administration of systemic antibiotics for VAP. Patients were tbllowed up for 28 days. Bacteriological eradication, clinical pulmonary infection score （CP1S）, and serum creatinine were assessed on day 7 of therapy. New resistance to amikacin, cure rate of VAP, weaning rate, and mortality were assessed on day 28. Results： The baseline characteristics of patients in both groups were similar. At the end of the treatment, 13 of the 32 initially detected bacterial isolates were eradicated in AA group, compared to 4 of 28 in placebo group （41% vs. 14%, P - 0.024）. As for patients, 11 of 27 patients treated with AA and 4 of 25 patients treated with placebo have eradication （41% vs. 16%, P = 0.049）. The adjunction of AA reduced CPIS （4.2 ± 1.6 vs. 5.8 ± 2.1, P = 0.007）. New drug resistance to amikacin and the change in serum creatinine were not detected in AA group. No significant differences in the clinical cure rate in survivors （48% vs. 35%, P = 0.444）, weaning rate （48% vs. 32%, P = 0.236）, and mortality （22% vs. 32%, P = 0.427） were detected between the two groups on day 28. Conclusions： As an adjunctive therapy of MDR-GNB VAP, AA successfully eradicated existing M
基金supported by the National Natural Science Foundation of China(No.31290221)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05050601)the Program for “Kezhen” Distinguished Talents in the Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences(No.2013RC102)
文摘Decomposition of soil organic matter(SOM) is of importance for CO_2 exchange between soil and atmosphere and soil temperature and moisture are considered as two important factors controlling SOM decomposition. In this study, soil samples were collected at 5 elevations ranging from 753 to 2 357 m on the Changbai Mountains in Northeast China, and incubated under different temperatures(5, 10, 15, 20, 25, and 30?C) and soil moisture levels(30%, 60%, and 90% of saturated soil moisture) to investigate the effects of both on SOM decomposition and its temperature sensitivity at different elevations. The results showed that incubation temperature(F = 1 425.10, P < 0.001), soil moisture(F = 1 327.65, P < 0.001), and elevation(F = 1 937.54, P < 0.001) all had significant influences on the decomposition rate of SOM. The significant effect of the interaction of incubation temperature and soil moisture on the SOM decomposition rate was observed at all the 5 sampling elevations(P < 0.001). A two-factor model that used temperature and moisture as variables fitted the SOM decomposition rate well(P < 0.001) and could explain 80%–93% of the variation of SOM decomposition rate at the 5 elevations. Temperature sensitivity of SOM decomposition, expressed as the change of SOM decomposition rate in response to a 10?C increase in temperature(Q_(10)), was significantly different among the different elevations(P < 0.01), but no apparent trend with elevation was discernible. In addition, soil moisture and incubation temperature both had great impacts on the Q_(10) value(P < 0.01), which increased significantly with increasing soil moisture or incubation temperature. Furthermore, the SOM decomposition rate was significantly related to soil total Gram-positive bacteria(R^2= 0.33, P < 0.01) and total Gram-negative bacteria(R^2= 0.58, P < 0.001). These findings highlight the importance of soil moisture to SOM decomposition and its Q_(10) value,which needs to be emphasized under warming climate scenarios.
基金Supported by the National Key Research and Development Program(973 Program)of China(No.2012CB417103)the Forestry Department of Qinghai Province,China(No.Y22LO300AJ)
文摘The responses of soil microbes to global warming and nitrogen enrichment can profoundly affect terrestrial ecosystem functions and the ecosystem feedbacks to climate change.However,the interactive effect of warming and nitrogen enrichment on soil microbial community is unclear.In this study,individual and interactive effects of experimental warming and nitrogen addition on the soil microbial community were investigated in a long-term field experiment in a temperate steppe of northern China.The field experiment started in 2006 and soils were sampled in 2010 and analyzed for phospholipid fatty acids to characterize the soil microbial communities.Some soil chemical properties were also determined.Five-year experimental warming significantly increased soil total microbial biomass and the proportion of Gram-negative bacteria in the soils.Long-term nitrogen addition decreased soil microbial biomass at the 0-10 cm soil depth and the relative abundance of arbuscular mycorrhizal fungi in the soils.Little interactive effect on soil microbes was detected when experimental warming and nitrogen addition were combined.Soil microbial biomass positively correlated with soil total C and N,but basically did not relate to the soil C/N ratio and pH.Our results suggest that future global warming or nitrogen enrichment may significantly change the soil microbial communities in the temperate steppes in northern China.
文摘Bacterial infection in the first month after liver transplantation is a frequent complication that poses a serious risk for liver transplant recipients as contributes substantially to increased length of hospitalization and hospital costs being a leading cause of death in this period. Most of these infections are caused by gramnegative bacilli, although gram-positive infections, especially Enterococcus sp. constitute an emerging infectious problem. This high rate of early postoperative infections after liver transplant has generated interest in exploring various prophylactic approaches to surmount this problem. One of these approaches is selective intestinal decontamination(SID). SID is a prophylactic strategy that consists of the administration of antimicrobials with limited anaerobicidal activity in order to reduce the burden of aerobic gram-negative bacteria and/or yeast in the intestinal tract and so prevent infections caused by these organisms. The majority of studies carried out to date have found SID to be effective in the reduction of gram-negative infection, but the effect on overall infection is limited due to a higher number of infection episodes by pathogenic enterococci and coagulase-negative staphylococci. However, difficulties in general extrapolation of the favorable results obtained in specific studies together with the potential risk of selection of multirresistant microorganisms has conditioned controversy about the routinely application of these strategies in liver transplant recipients.
文摘Objective： To evaluate the in vitro antibacterial properties and the ability to potentiate some common antibiotics effects of the methanol extracts of 11 Cameroonian food plants on 29 Gram-negative bacteria expressing multidrug resistant （MDR） phenotypes. Methods： The antimicrobial activity of the extracts was performed using the broth microdilution method. The phytochemical screening of these extracts was also performed using standard methods. Resalts： Ocimum basilicum, Gnetum africanum and Eucalyptus robusta extracts possessed an antibacterial activity against all the 29 studied bacteria. The extracts from G. africanum and E. robusta were the most active with the lowest minimal inhibitory concentration of 64 p, g/mL on Escherichia coil AG100A for both extracts and also against Klebsiella pneumoniae K24 for G. africanum. When tested in the presence of phenylalanine-arginine 13 -Naphtylamide （PA 13 N）, an efflux pump inhibitor, the extract of Thymus vulgafis and E. Robusta showed the best activities on most tested strains. E. Robusta extract showed good synergistic effects, improving the activity of commonly used antibiotics in about 85% of cases. Coaclasion： The overall results obtained provide the baseline information for the use of the tested plants in the treatment of bacterial infections.
基金supported by the National Natural Science Foundation of China(No.51478237)
文摘Pharmaceutical wastewater treatment plants（WWTPs） are thought to be a ＂seedbed＂ and reservoirs for multi-antibiotic resistant pathogenic bacteria which can be transmitted to the air environment through aeration. We quantified airborne multi-antibiotic resistance in a full-scale plant to treat antibiotics-producing wastewater by collecting bioaerosol samples from December2014 to July 2015. Gram-negative opportunistic pathogenic bacteria（GNOPB） were isolated, and antibiotic susceptibility tests against 18 commonly used antibiotics, including 11 β-lactam antibiotics, 3 aminoglycosides, 2 fluoroquinolones, 1 furan and 1 sulfonamide, were conducted.More than 45% of airborne bacteria isolated from the pharmaceutical WWTP were resistant to three or more antibiotics, and some opportunistic pathogenic strains were resistant to 16 antibiotics, whereas 45.3% and 50.3% of the strains isolated from residential community and municipal WWTP showed resistance to three or more antibiotics. The calculation of the multiple antibiotic resistance（MAR） index demonstrated that the air environment in the pharmaceutical WWTP was highly impacted by antibiotic resistance, while the residential community and municipal WWTP was less impacted by antibiotic resistance. In addition, we determined that the dominant genera of opportunistic pathogenic bacteria isolated from all bioaerosol samples were Acinetobacter, Alcaligenes, Citrobacter, Enterobacter, Escherichia, Klebsiella, Pantoea, Pseudomonas and Sphingomonas. Collectively, these results indicate the proliferations and spread of antibiotic resistance through bioaerosols in WWTP treating cephalosporin-producing wastewater, which imposed a potential health risk for the staff and residents in the neighborhood, calling for administrative measures to minimize the air-transmission hazard.
文摘BACKGROUND Diabetic foot ulceration(DFU)is the prime health concern globally.It accounts for the major burden related to disease mortality and morbidity and economic cost.The timely and early recognition of the DFU can help present its occurrence and improve clinical outcomes.AIM To evaluate interrelationships between foot ulcers,risk factors,and antibiotic resistance among diabetic patients having ulcers in their foot.METHODS The databases such as PubMed,ERIC,Medline,and Google Scholar were extensively used for the extraction of studies.The selected studies were published within the time-period of 2014-2018.Ten studies were selected,which were found to be completely relevant to the current study.RESULTS The prevalence of diabetic foot ulcers among the population was evaluated,and the associated risk factors with its prevalence.Moreover,few studies also reported on the bacteria that are found to be most prevailing among diabetic patients.A narrative discussion was drawn through this analysis,which was used to highlight the specific area of research through selected studies,extraction of the significant information that matched with the topic of research,and analysis of problem through the findings of the selected articles.The results helped in assessing significant knowledge regarding the risk factors of diabetic foot ulcers and the role of antimicrobial resistant in its treatment.CONCLUSION The gram-negative bacteria were found to be the most common reason for diabetic foot ulcers.The study only included 10 studies that are not sufficient to produce generalized results,and no information was reported on the tests required to analyze antimicrobial susceptibility that can guide clinicians to propose better and sound treatment plans.It is evident that most study results depicted that the most common risk factors were found to be hypertension and neuropathy.
文摘INTRODUCTIONAcute narcotizing pancreatitis usually takes a severe clinical course and is associated with multiple organ dysfunction .With the further understanding of pathophysiological events of acute pancreatisis and the therapeutic measuses taken by the clinicians ,the patients can pass through the critical carry stages ,and then the septic complication caused by rtanslocated bacteria, mostly gram-negative microbes from the intestines ensues[1].
基金financially supported by SERC Fast Track OYSSchem,Department of Science and Technology(DST),New Delhi,India[grant No.304/2004(SR/FT/L-129/2004)]
文摘Objective:To investigate antibacterial potential of Trifolium alexandrinum(T.alexandrinum) Linn,against seven gram positive and eleven gram negative hospital isolated human pathogenic bacterial strains responsible for many tropical diseases.Methods:Non-polar and polar extracts of the leaves of T.alexandrinum i.e.,hexane,dichloromethane(DCM),ethyl acetate(EtOAc), methanol(MeOH) and aqueous(AQ) extracts at five different concentrations(1,2,5,10 and 15 mg/ mL) were prepared to evaluate their antibacterial value.NCCL standards were strictly followed to perform antimicrobial disc susceptibility test using disc diffusion method.Results:Polar extracts demonstrated significant antibacterial activity against tested pathogens.EtOAc and MeOH extracts showed maximum antibacterial activity with higher inhibition zone and were found effective against seventeen of the tested pathogens.While AQ plant extract inhibited the growth of sixteen of the test strains.EtOAc and MeOH plant extracts inhibited the growth of all seven gram positive and ten of the gram negative bacterial strains.Conclusions:The present study strongly confirms the effectiveness of crude leaves extracts against tested human pathogenic bacterial strains causing several tropical diseases.Since Egyptian clover is used as a fodder plant,it could be helpful in controlling various infectious diseases associated with cattle as well.
文摘The use of antibiotics in humans and animals has been marked as a significant step in health due to their effectiveness in controlling and treating bacterial infections. The misuse and overuse of antibiotics have been identified as risk factors for bacterial resistance since microorganisms adapt and develop mechanisms to defend against antibiotics. According to the Centers for Disease Protection and Control (CDC), around 23,000 individuals die every year in the United States due to antibiotic resistance complications. As a result, a demand for alternative treatments has been a goal for scientists as the microbes adapt to selective pressure. The aim of this study is to test the antibacterial activity of leaf extracts of Peganum harmala and Haloxylon salicornicum on both Gram-positive and Gram-negative bacteria on various mediums. The results of the study showed that both P. harmala and H. salicornicum inhibited the bacterial growth in two different media. The results were also compared with different common antibiotics used in both human’s and animal’s fields and showed a promising outcome as alternative antibiotics.
文摘目的评价基质辅助激光解吸电离飞行时间质谱（matrix assisted laser desorption ionisation time of flight mass spectrometry, MALDI-TOF-MS）技术检测临床常见革兰阴性杆菌的临床应用价值。方法1665株革兰阴性杆菌经VITEK2Compact鉴定到属和种，采用MALDI—TOF—MS对1665株革兰阴性杆菌进行种属检测，并计算鉴定正确率。结果1665株菌包括27个菌属，73个菌种。主要革兰阴性杆菌菌属鉴定整体正确率为95．7％，菌种整体正确率为85．5％。其中菌属鉴定正确率最高的是布鲁菌属和沙门菌属，正确率均为100．0％；菌种鉴定正确率最高的为危险罗尔斯顿菌和摩氏摩根菌，正确率均为100．0％。结论MALDI—TOF—MS技术鉴定细菌快速、准确、方便，且成本低，适用于临床实验室的快速鉴定诊断。
基金Key Research Program for International Cooperation(2005DFA30610)Program for New Century Excellent Talents in University(NCET-05-0755)+2 种基金National Natural Science Foundation(30700128)Natural Science Foundation of Hainan Province(80623)Research Foundation of Education Department of Hainan Province(Hj200731)
文摘Antimicrobial proteins and peptides had been found from a wide variety of organisms in the last few years These molecules have attracted much research interest because of their biochemical diversity, broad specificity on anti-viral, anti-bacterial, anti-fungi, anti-protozoan parasites, anti-tumoural, and wound-healing effects. Antimicrobial proteins and peptides play key roles in innate immunity. They interact directly with bacteria and kill them. The brown-spotted grouper, Epinephelusfario, is an important marine fish cultured in southem China. Recently, bacteria and virus have caused high mortality in E. fario cultures, but its endogenous antimicrobial peptides and proteins have not been explored. An antimicrobial component was found from the skin homogenate of E. fario. After the skin homogenate was digested with trypsin, its antimicrobial activity was lost, which showed that the antimicrobial component is a protein. The antimicrobial protein （Efap） was purified from the skin homogenate of E. fario by successive ion-exchange and gel filtration chromatography. Efap was demonstrated to be single protein band by SDS-PAGE, with the apparent molecular weight of 41 kD. Efap exhibited antimicrobial activity both for the Gram-positive bacteria, Staphylococcus aureus, Micrococcus luteus and Bacillus subtilis, and for the Gram-negative bacteria, Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio fluvialis, Pasteurella multocida, Aeromonas hydrophila, Eschrrichiu coli, and Pseudomonas aeruginosa. Except A. hydrophila, P. aeruginosa, and E. coli （MIC〉20 mol/L）, most of the tested Gram-negative bacteria were sensitive to Efap （MIC〈20 mol/L）. Interestingly, Efap showed potent antimicrobial activity against Gram-positive bacteria S. aureus （MIC 5-10 mol/L） but comparatively weak antimicrobial activity against M. luteus and B. subtilis. The broad antimicrobial activities of Efap suggest that it contributes to the innate host defence of E. fario.
文摘Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.
基金This study was supported by a grant from the National Natural Science Foundation of China(81870457).
文摘Background:Acute suppurative terminal cholangitis(ASTC)is rarer than acute obstructive cholangitis and is not well studied.To explore this subtype of acute cholangitis,we described our clinical experience with ASTC.Methods:We performed a retrospective review of patients with ASTC admitted to our center from September 2014 to August 2020.We analyzed their clinical characteristics,including etiology,clinical manifestations,imaging features,treatment and prognosis.Results:A total of 32 ASTC patients were included in the analysis.The majority of the patients had a history of biliary operations,and clinical manifestations were occult and atypical.The positive rate of bacterial culture was 46.9%.All the patients had typical imaging features on computed tomography and magnetic resonance imaging.Treatment with effective antibiotics was provided as soon as diagnosis was established.After treatment,most patients had a good outcome.Elevated levels of total bilirubin,aspartate aminotransferase,procalcitonin and gamma-glutamyltransferase were the characteristics of critically ill patients and were associated with relatively poor prognosis.Conclusions:Our results demonstrated that ASTC should be recognized as a new subtype of acute cholangitis,and that earlier diagnosis and more personalized treatments are needed.
基金Supported by the National Key R&D Precision Medicine Program,No.2017YFC0908100Shanghai Key Clinical Specialty Grant,No.Shslczdzk05801.
文摘BACKGROUND Immunosuppression is an important factor in the incidence of infections in transplant recipient.Few studies are available on the management of immunosuppression(IS)treatment in the liver transplant(LT)recipients complicated with infection.The aim of this study is to describe our experience in the management of IS treatment during bacterial bloodstream infection(BSI)in LT recipients and assess the effect of temporary IS withdrawal on 30 d mortality of recipients presenting with severe infection.AIM To assess the effect of temporary IS withdrawal on 30 d mortality of LT recipients presenting with severe infection.METHODS A retrospective study was conducted with patients diagnosed with BSI after LT in the Department of Liver Surgery,Renji Hospital from January 1,2016 through December 31,2017.All recipients diagnosed with BSI after LT were included.Univariate and multivariate Cox regression analysis of risk factors for 30 d mortality was conducted in the LT recipients with Gram-negative bacterial(GNB)infection.RESULTS Seventy-four episodes of BSI were identified in 70 LT recipients,including 45 episodes of Gram-positive bacterial(GPB)infections in 42 patients and 29 episodes of GNB infections in 28 patients.Overall,IS reduction(at least 50%dose reduction or cessation of one or more immunosuppressive agent)was made in 28(41.2%)cases,specifically,in 5(11.9%)cases with GPB infections and 23(82.1%)cases with GNB infections.The 180 d all-cause mortality rate was 18.5%(13/70).The mortality rate in GNB group(39.3%,11/28)was significantly higher than that in GPB group(4.8%,2/42)(P=0.001).All the deaths in GNB group were attributed to worsening infection secondary to IS withdrawal,but the deaths in GPB group were all due to graft-versus-host disease.GNB group was associated with significantly higher incidence of intra-abdominal infection,IS reduction,and complete IS withdrawal than GPB group(P<0.05).Cox regression showed that rejection(adjusted hazard ratio 7.021,P=0.001)and complete IS withdrawal(adjusted hazard r
文摘OBJECTIVE： To evaluate the antibacterial activity of the combination of different honey brands and methanolic fraction of Herba Ocimi Basilici using agar well diffusion assay. METHODS： The antibacterial activity was deter- mined against thirteen pathogenic bacterial clini- cal isolates including six gram negative （Klebsiella pneumonia, Pseudomonas aeroginosa, Escherichia coli, Salmonella typhi, Salmonella typhimirium, Xanthomonas campestris） and six gram positive strains （Enterococcus faecalis faecalis, Bacillus subti- lis, Staphylococcus aureus, Clostridium perfringens type C, Clostridium perfringens type D, CIostridium chauvoei）. Agar well diffusion method was used while zones of inhibition were measured with verni- er scale. RESULTS： At higher concentration, all the honey brands showed good to significant activity. Thehighest activity was observed for Hamdard brand honey （27.60±0.40） against Enterococcus faecalis. CONCLUSION： These results revealed that combi- nations of plant extracts of Herba Ocimi Basilici with honey can be used for the development of potent and novel antibacterial agents.
文摘The incidence of gram-negative multidrug-resistant(MDR) bacterial pathogens is increasing in hospitals and particularly in the intensive care unit(ICU) setting. The clinical consequences of infections caused by MDR pathogens remain controversial. The purpose of this review is to summarize the available data concerning the impact of these infections on mortality in ICU patients. Twenty-four studies, conducted exclusively in ICU patients, were identified through Pub Med search over the years 2000-2015. Bloodstream infection was the only infection examined in eight studies, respiratory infections in four and variable infections in others. Comparative data on the appropriateness of empirical antibiotic treatment were provided by only seven studies. In ten studies the presence of antimicrobial resistance was not associated with increased mortality; on the contrary, in other studies a significant impact of antibiotic resistance on mortality was found, though, sometimes, mediated by inappropriate antimicrobial treatment. Therefore, a direct association between infections due to gram-negative MDR bacteria and mortality in ICU patients cannot be confirmed. Sample size, presence of multiple confounders and other methodological issues may influence the results. These data support the need for further studies to elucidate the real impact of infections caused by resistant bacteria in ICU patients.
基金Supported by the National Natural Science Foundation of China (Grant No. 50373036)Fok Ying Tung Education Foundation (Grant No. J20040212)
文摘The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also provide an effective synthesis method for preparing functional bioconjugated nanoparticles here.
基金funded by the Basic Science Research Program of the National Research Foundation of Korea(NRF)which is funded by the Ministry of Science,ICT&Future Planning(NRF-2018R1D1A3B07041059 to M.M.and NRF-2016R1A5A2012284 to Y.-M.R)+3 种基金by the Cooperative Research Program for Agriculture Science and Technology Development(Project No.PJ01428603)Rural Development Administration,Republic of Koreaby the Korea Health Technology R&D Project through the Korea Health Industry Development Institute(KHIDI)funded by the Ministry of Health&Welfare,Republic of Korea(grant number:HF21C0021).
文摘Alzheimer's disease(AD)is the most serious age-related neurodegenerative disease and causes destructive and irreversible cognitive decline.Failures in the development of therapeutics targeting amyloid-β(Aβ)and tau;principal proteins inducing pathology in AD,suggest a paradigm shift towards the development of new therapeutic targets.The gram-negative bacteria and lipopolysaccharides(LPS)are attractive new targets for AD treatment.Surprisingly,an altered distribution of gram-negative bacteria and their LPS has been reported in AD patients.Moreover,gram-negative bacteria and their LPS have been shown to affect a variety of AD-related pathologies,such as Aβ homeostasis,tau pathology,neuroinflammation,and neurodegeneration.Moreover,therapeutic approaches targeting gram-negative bacteria or gram-negative bacterial molecules have significantly alleviated AD-related pathology and cognitive dysfunction.Despite multiple evidence showing that the gram-negative bacteria and their LPS play a crucial role in AD pathogenesis,the pathogenic mechanisms of gram-negative bacteria and their LPS have not been clarified.Here,we summarize the roles and pathomechanisms of gram-negative bacteria and LPS in AD.Furthermore,we discuss the possibility of using gram-negative bacteria and gram-negative bacterial molecules as novel therapeutic targets and new pathological characteristics for AD.
基金supported by the National Key Research and De-velopment Program of China[grant number 2022YFE0199800]Key R&D Program of Shandong Province[grant number 2020CXGC011305]+1 种基金Shandong Provincial Natural Science Foundation[grant number ZR2020MH308]the National Natural Science Foundation of China[grant number 82,271,658].
文摘Tigecycline serves as a critical“final-resort”antibiotic for treating bacterial infections caused by multidrug-resistant bacteria for which treatment options are severely limited.The increasing prevalence of tigecycline resistance,particularly among Gram-negative bacteria,is a major concern.Various mechanisms have been iden-tified as contributors to tigecycline resistance,including upregulation of nonspecific Resistance Nodulation Divi-sion(RND)efflux pumps due to mutations in transcriptional regulators,enzymatic modification of tigecycline by monooxygenase enzymes,and mutations affecting tigecycline binding sites.This review aims to consolidate our understanding of tigecycline resistance mechanisms in Gram-negative bacteria and offer insights and perspectives for further drug development.
