This study was conducted to isolate and identify antibiotic resistant bacteria in fresh tomato sold in three different local markets of Dhaka city. On an average 〉 5.0 log CFU/g of natural microbial populations and c...This study was conducted to isolate and identify antibiotic resistant bacteria in fresh tomato sold in three different local markets of Dhaka city. On an average 〉 5.0 log CFU/g of natural microbial populations and coliform bacteria was present in the samples. Prevalence of Salmonella spp., E. coli, Listeria spp., and Yersinia spp., were recorded through cultivation dependent assay of tomato samples of different markets. Almost all of the isolates were uniformly resistant to rifampicin, erythromycin, clindamycin and oxacillin （100%）, vancomycin （93%）, amoxicillin （87%）, whereas 60% of the isolates were found to be resistant to ampicillin and cephalexin. Antibiotic sensitivity test of the presumptive E. coli and Salmonella spp. and corresponding plasmid profiling indicated a correlation of plasmid mediated multidrug resistance （MDR） of these environmental bacteria. Washing with sanitizing agents such as acidified sodium chlorite （ASC） and 200 ppm chlorinated water was able to reduce _〈 2.0 log CFU/g of natural microflora and coliform bacteria. In contrast, ASC was able to reduce 〈 2.0 log CFU/g of other food borne pathogens and, chlorinated water was able to reduce up to undetectable level. Therefore, washing of tomato with 200 ppm chlorinated water could be useful in reducing the pathogen populations on tomatoes.展开更多
Biofilms are dense bacterial colonies, derived from microbially derived sessile community, networked within a polysaccharide matrix with a distinct architecture that has the attachment potential to both alive and abio...Biofilms are dense bacterial colonies, derived from microbially derived sessile community, networked within a polysaccharide matrix with a distinct architecture that has the attachment potential to both alive and abiotic surfaces. <i>Pseudomonas aeruginosa</i> is a model biofilm forming microorganism associated with remarkable morbidity and mortality rate due to emergence of antibiotic resistant pathogenic bacteria. Moreover, <i>Pseudomonas aeruginosa</i> originating from a biofilm is more resistant to a wide range of antibiotics than the planktonic bacteria. This research was planned to develop a comparative study of the biofilm production between potential, antimicrobial resistance of <i>Pseudomonas aeruginosa</i> isolated from mature environmental biofilm and clinical strain of the same species that did not derive from biofilm. It was observed that the <i>Pseudomonas aeruginosa</i> from environmental isolates were resistant to 15 prominent antibiotics, while clinical strain was comparatively resistant to only few of them. A confirmatory analysis of biofilm formation and antibiotic resistance pattern of these two groups of organisms was checked by 96-well microtiter plate and the disc diffusion method respectively. Finally, the results portrayed that the environmental strains with high drug resistance, potentially formed a considerable amount of biofilm in the period of a week whereas;clinical stains formed a negligible amount of biofilm within the same time frame.展开更多
The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacteri...The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.展开更多
[Objective]This study aimed to investigate the mutations of OmpF from an isolated antibiotic resistant Escherichia coli strain.[Methods]The mutant OmpF（mOmpF）from antibiotic resistant E.coli was amplified by PCR wit...[Objective]This study aimed to investigate the mutations of OmpF from an isolated antibiotic resistant Escherichia coli strain.[Methods]The mutant OmpF（mOmpF）from antibiotic resistant E.coli was amplified by PCR with Pfu DNA polymerase and ligated into the expression vector pET28a.Subsequently,the expression vector pET28-mOmpF was sequenced and analyzed by DNAMAN software and Swiss-Model online.[Result]Sequence analysis revealed that the open reading fragment of mOmpF was 903 bp long,which was mutated dramatically compared to that of the 1 020 bp long model OmpF.The DNA sequence shared only54.5%homology with OmpF.mOmpF was 44.6%identical to that of OmpF.Protein structure predication and analysis through Swiss-Model online suggested that the structure of mOmpF changed dramatically compared to OmpF.[Conclusion]The present study provided basis for further analyzing the relationships between the structure and functions of mOmpF from antibiotic resistant E.coli.展开更多
The fate of indigenous surface-water and wastewater antibiotic resistant bacteria in a mild slope stream simulated through a hydraulic channel was investigated in outdoor experiments.The effect of（i） natural（dark）...The fate of indigenous surface-water and wastewater antibiotic resistant bacteria in a mild slope stream simulated through a hydraulic channel was investigated in outdoor experiments.The effect of（i） natural（dark） decay,（ii） sunlight,（iii） cloudy cover,（iv） adsorption to the sediment,（v） hydraulic conditions,（vi） discharge of urban wastewater treatment plant（UWTP）effluent and（vii） bacterial species（presumptive Escherichia coli and enterococci） was evaluated.Half-life time（T1/2） of E. coli under sunlight was in the range 6.48–27.7 min（initial bacterial concentration of 10^5 CFU/mL） depending on hydraulic and sunlight conditions. E. coli inactivation was quite similar in sunny and cloudy day experiments in the early 2 hr, despite of the light intensity gradient was in the range of 15–59 W/m^2; but subsequently the inactivation rate decreased in the cloudy day experiment（T1/2= 23.0 min） compared to sunny day（T1/2= 17.4 min）. The adsorption of bacterial cells to the sediment（biofilm） increased in the first hour and then was quite stable for the remaining experimental time. Finally, when the discharge of an UWTP effluent in the stream was simulated, the proportion of indigenous antibiotic resistant E. coli and enterococci was found to increase as the exposure time increased, thus showing a higher resistance to solar inactivation compared to the respective total populations.展开更多
In this study,bismuth ferrite(BiFeO_(3),BFO)catalysts doped with different contents of peanut shell biochar(BC)were prepared and used in the removal of antibiotic-resistant bacteria(ARB)by peroxymonosulfate(PMS)activa...In this study,bismuth ferrite(BiFeO_(3),BFO)catalysts doped with different contents of peanut shell biochar(BC)were prepared and used in the removal of antibiotic-resistant bacteria(ARB)by peroxymonosulfate(PMS)activation from wastewater.The PMS(0.03 mM)/5%BC-BFO(0.5 g L^(−1))system removed 1.92 log ARB within 10 min of reaction at a reaction rate of 0.4401 min^(−1).Raman spectra analysis revealed that 5%BC-BFO exhibited more defects and oxygen vacancies(Ov),which provided active sites for PMS activation to generate SO_(4)^(⋅−),O_(2)^(⋅−),and^(1)O_(2),thereby promoting ARB inactivation.The oxidation of PMSO to PMSO₂suggests that high-valent iron-oxo species may also be involved in the inactivation of ARB.The PMS/5%BC-BFO system caused oxidative damage to the ARB cell membrane,increasing its permeability from 4.34%to 46.00%.Simultaneously,it triggered the activation of bacterial self-defense mechanisms and a cascade reaction,leading to the upregulation of intracellular reactive oxygen species(ROS)levels(rising from 6.34%to 62.90%),ultimately resulting in ARB inactivation.In addition,the ARB removal under PMS activation by the fourth recycled 5%BC-BFO catalyst was 62.6%of that by the fresh 5%BC-BFO.In summary,this study proposes a low-cost and easily synthesized novel catalyst for the efficient ARB removal from wastewater.展开更多
Recent studies have shown a noticeable increase in global Helicobacter pylori(H.pylori)resistance,with clarithromycin resistance surpassing 15%in various areas.However,inadequate epidemiological monitoring,especially ...Recent studies have shown a noticeable increase in global Helicobacter pylori(H.pylori)resistance,with clarithromycin resistance surpassing 15%in various areas.However,inadequate epidemiological monitoring,especially in developing countries,and the absence of uniform testing methods lead to discrepancies between regions and a possible underestimation of resistance levels.The complexity of treating H.pylori is driven by its highly dynamic genome,which is prone to frequent mutations contributing to phenotypical resistance.The usual course of action in empirical treatment involves using a combination of various drugs simultaneously,leading to significant resistance selection pressure and potential side effects.The emergence of H.pylori strains resistant to multiple drugs is closely tied to failures in first-line treatment,highlighting the need to prevent further resistance by using optimal initial empirical therapy or regimens guided by antibiotic susceptibility testing,requiring a collection of mixed samples and multiple isolates for accurate assessment.The emergence of new treatments like potassium-competitive acid blockers offers a hopeful approach to decrease antimicrobial usage while still ensuring effectiveness in comparison to traditional therapies with proton pump inhibitors.Additionally,the use of probiotics is under investigation to identify specific strains and formulations that may mitigate therapy-associated adverse effects.展开更多
Antibiotic resistance genes(ARGs) are recognized as a primary threat to the sustainability of environment and human health in the 21^(st) century.Nanomaterials(NMs) have attracted substantial attention due to their un...Antibiotic resistance genes(ARGs) are recognized as a primary threat to the sustainability of environment and human health in the 21^(st) century.Nanomaterials(NMs) have attracted substantial attention due to their unique dimensions and structures.Unfortunately,emerging evidence suggests that NMs may facilitate the transmission of ARGs.It is crucial to elucidate how NMs affect the evolution and dissemination of ARGs.The current review comprehensively examines the role of NMs in the widespread transmission of ARGs in aquatic environments and the underlying mechanisms involved in the process.It aims to clarify the effects and mechanisms of NMs on the horizontal gene transfer processes that are associated with ARGs,including the enhancement of cell membrane permeability,the formation of nanopores on membranes,promotion of mutagenesis,and the generation of reactive oxygen species(ROSs).Furthermore,the trade-off between the removal of ARGs and horizontal transfer has been elucidated.The review aspires to guide future research directions,advance knowledge on the implications of NMs in the field of ARGs' transmission,and provide a theoretical foundation for the development of safer and more effective applications of NMs.展开更多
Objective:To analyse the prevalence of serotypes,antibiotic resistance,and virulence genes of Group B Streptococcus(GBS)strains isolated from pregnant women at 35-37 weeks of gestation in Ho Chi Minh City,Vietnam,from...Objective:To analyse the prevalence of serotypes,antibiotic resistance,and virulence genes of Group B Streptococcus(GBS)strains isolated from pregnant women at 35-37 weeks of gestation in Ho Chi Minh City,Vietnam,from January 2022 to January 2023.Methods:GBS strains were isolated through selective culture methods and confirmed by PCR.Serotyping,virulence gene detection,and antibiotic susceptibility testing were performed using PCR,gel electrophoresis techniques and Kirby-Bauer test.Results:Totally,61 GBS isolated from 300 participants have been identified including seven GBS serotypes(Ⅰa,Ⅰb,Ⅱ,Ⅲ,Ⅳ,Ⅴ,andⅥ).SerotypesⅦ,Ⅷ,andⅨwere not detected in the study population.Antibiotic resistance patterns varied:13.1%of isolates were fully susceptible,while the majority showed multi-drug resistance,with 34.4%resistant to three antibiotics.SerotypeⅠa demonstrated high susceptibility(35.7%),while serotypeⅢshowed extensive resistance,with 87.5%being resistant to at least three antibiotics.All strains are susceptible to vancomycin andβ-lactams susceptibility also remained high,but resistance to clindamycin,erythromycin,and tetracycline was high(>65%).The virulence genes scpB,cylB,fbsB,and cfb were highly prevalent(90%-100%),indicating their potential for vaccine and diagnostic development.Conclusions:Our findings provide valuable insights into GBS serotypes,resistance,and virulence factors,contributing to community monitoring,preventive measures,diagnostics,and vaccine development.However,the limited sample size necessitates further research.展开更多
In this study, bacteriophage of an antibiotic-resistant Escherchia coil strain isolated from feces of chicken was isolated. Its host range was determined by the method of spotting sample on monolayer agar, and its lys...In this study, bacteriophage of an antibiotic-resistant Escherchia coil strain isolated from feces of chicken was isolated. Its host range was determined by the method of spotting sample on monolayer agar, and its lysis titer, optimal multiplicity of infection （MOI）, temperature tolerance and pH tolerance were determined by the double-layer agar plate method. The results showed that the bacteriophage had a broad host range. The biological assay demonstrated that two strains of E. coil were fully lysed and one strain of E. coil was weakly lysed by the bacteriophage. The lysis titer and MOI of the bacteriophage were 1.20×10^8 PFU/ml and 1, respec- tively. Under the optimum temperature of 40℃, the Jysis titer of the bacteriophage reached 8.90×10^9 PFU/ml; however, the bacteriophage lost its infectivity at the tem- perature of 80℃. In the pH range of 5-11, the lysis titer of the bacteriophage ranged from10^6 to 10^9 PFU/mI. Under the condition of pH 4 and 12, the bacterio- phage was invalid.展开更多
Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic ba...Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic bacteria and use of two antibiotics might prevent the emergence of resistance to either. In this study, synergistic effect of combined antibiotics against multidrug resistant human pathogenic bacterial isolates from poultry droppings in Akure, Nigeria was examined. Collection of samples, isolation and identification of bacteria were carried out using standard microbiological method, antibiotic sensitivity test was performed by disc diffusion method and zone of inhibition was used to interpret the sensitivity test as resistant, susceptible or intermediate while combined effects of two antibiotics were investigated by macrobroth dilution and checkerboard assay methods while the synergetic effects of combined antibiotics were calculated using Fractional Inhibitory Concentration (FIC) and percentage synergistic interaction was calculated. All the ten (10) species of bacterial isolates were multidrug resistant and are less resistant to ofloxacin. The highest percentage synergistic interactions observed were Ofloxacin + Amoxicillin (90%), Ciprofloxacin + Amoxicillin (90%), Tetracycline + Amoxicillin (70%), Tetracycline + Augmentin (80%), Cotrimoxazol + Amoxicillin (50%), Cotrimoxazol + Augmentin (70%), Chloramphenicol + Amoxicillin (70%) and Chloramphenicol + Augmentin (80%). Poultry droppings is a potential source of human pathogenic bacteria, high frequency of multiple antibiotic resistance bacteria observed in this study is of great treat to man as this may cause the treatment of infection caused by these bacteria to be difficult. Combination of beta-lactam antibiotic with fluoroqunolones, tetracycline, Chloramphenicol and Cotrimoxazole was synergetic and this will reduce dose related toxicity and prevent resistance to single antibiotic.展开更多
Once contaminate the drinking water source,antibiotic resistance genes(ARGs)will propagate in drinking water systems and pose a serious risk to human health.Therefore,the drinking water treatment processes(DWTPs)are c...Once contaminate the drinking water source,antibiotic resistance genes(ARGs)will propagate in drinking water systems and pose a serious risk to human health.Therefore,the drinking water treatment processes(DWTPs)are critical to manage the risks posed by ARGs.This study summarizes the prevalence of ARGs in raw water sources and treated drinking water worldwide.In addition,the removal efficiency of ARGs and related mechanisms by different DWTPs are reviewed.Abiotic and biotic factors that affect ARGs elimination are also discussed.The data on presence of ARGs in drinking water help come to the conclusion that ARGs pollution is prevalent and deserves a high priority.Generally,DWTPs indeed achieve ARGs removal,but some biological treatment processes such as biological activated carbon filtration may promote antibiotic resistance due to the enrichment of ARGs in the biofilm.The finding that disinfection and membrane filtration are superior to other DWTPs adds weight to the advice that DWTPs should adopt multiple disinfection barriers,as well as keep sufficient chlorine residuals to inhibit re-growth of ARGs during subsequent distribution.Mechanistically,DWTPs obtain direct and inderect ARGs reduction through DNA damage and interception of host bacterias of ARGs.Thus,escaping of intracellular ARGs to extracellular environment,induced by DWTPs,should be advoided.This review provides the theoretical support for developping efficient reduction technologies of ARGs.Future study should focus on ARGs controlling in terms of transmissibility or persistence through DWTPs due to their biological related nature and ubiquitous presence of biofilm in the treatment unit.展开更多
Manure application as fertilizer can increase environmental exposure risk,as antibiotics,antibiotic resistance bacteria(ARB),and antibiotic resistant genes(ARGs)can be transmitted to agricultural fields,and adjacent n...Manure application as fertilizer can increase environmental exposure risk,as antibiotics,antibiotic resistance bacteria(ARB),and antibiotic resistant genes(ARGs)can be transmitted to agricultural fields,and adjacent natural systems.Understanding how specific antibiotics and ARGs respond within different manure fractions during on-farm management is limited.The study objective was to conduct a mass flow analysis determining the fate of antibiotic resistance factors(antibiotics,ARGs,and ARB)through solid-liquid separation,with the solid fraction continuing through a bedding recovery unit(BRU)via high temperature rotary composting for use of the manure solids as dairy cow bedding.The results show that most of the manure mass containing the antibiotic resistance factors went untreated following solid-liquid separation,with 95%of the mass leaving the separator as a liquid and pumped to a storage lagoon for field application and 5%proceeding to BRU processing.The tetracyclines and tulathromycin sorbed to the manure solids,while the beta lactams,ampicillin,and benzylpenicilloic acid were only found in the liquid fraction.The removal of antibiotic residuals during the BRU composting was insignificant,yet 40%-73%of the antibiotics were in the liquid fraction.The BRU composting was 100%effective in removing the ARB examined.Five of the eight ARGs(intl1,sul1,tetQ,tetX,and tetM)had significant reduction(>95%)following the BRU composting treatment.While the three other ARGs(tetW,ermB,and bla2)remained constant despite treatment.This study highlighted the importance of examining manure management from a mass balance perspective and understanding antibiotic resistance risk factors.展开更多
This study compared three different disinfection processes （chlorination, E-beam, and ozone） and the efficacy of three oxidants （H202, S2O8-, and peroxymonosulfate （MPS）） in removing antibiotic resistant bacter...This study compared three different disinfection processes （chlorination, E-beam, and ozone） and the efficacy of three oxidants （H202, S2O8-, and peroxymonosulfate （MPS）） in removing antibiotic resistant bacteria （ARB） and antibiotic resistance genes （ARGs） in a synthetic wastewater. More than 30 mg/L of chlorine was needed to remove over 90% of ARB and ARG. For the E-beam method, only 1 dose （kGy） was needed to remove ARB and ARG, and ozone could reduce ARB and ARG by more than 90% even at 3 mg/L ozone concentration. In the ozone process, CT values （concentration × time） were compared for ozone alone and combined with different catalysts based on the 2-log removal of ARB and ARG. Ozone treatment yielded a value of 31 and 33 （mg·min）/L for ARB and ARGs respectively. On the other hand, ozone with persulfate yielded 15.9 and 18.5 （mg.min）/L while ozone with monopersulfate yielded a value of 12 and 14.5 （mg·min）/L. This implies that the addition of these catalysts significantly reduces the contact time to achieve a 2-log removal, thus enhancing the process in terms of its kinetics.展开更多
This paper presents a compartmental model for bacterial infections in a population distributed over a network of individuals.Within each node,individuals interact,bacteria can be transmitted and the disease may be spr...This paper presents a compartmental model for bacterial infections in a population distributed over a network of individuals.Within each node,individuals interact,bacteria can be transmitted and the disease may be spread;moreover,the acquisition of bacterial antibiotic resistance is considered.In addition,nodes are connected through weighted edges,and consequently individuals from different nodes may interact.As a result,the infection may be propagated over the network.We perform an analysis on this propagation as well as numerical simulations in order to illustrate the validity of the model.展开更多
<b>Introduction:</b> Oral cancer is the third most prominent type of cancer in Bangladesh. During or after oral cancer treatment, immune-compromised cancer patients may be susceptible to an infection by mu...<b>Introduction:</b> Oral cancer is the third most prominent type of cancer in Bangladesh. During or after oral cancer treatment, immune-compromised cancer patients may be susceptible to an infection by multi-drug-resistant opportunistic microbes. This study aims to identify the prevalent microorganisms from the infected site of oral cancer patients and observe their antibiotic susceptibility pattern. <b>Materials and Methods:</b> Clinical samples were collected from the infected sites of oral cancer patients and healthy people. The swabs collected were placed on nutrient agar slant, then incubated for 24 hours at 37ºC. Bacteria from the slant were inoculated in several selective media (Mannitol Salt Agar Media, KF Streptococcus Agar media, Cetrimide Agar, Eosin Methylene Blue Agar). Several biochemical tests identified opportunistic microorganisms. Finally, the antibiotic susceptibility test was performed by the Kirby Bauer disc diffusion method. <b>Results:</b> The study found that 65.4% of microbes isolated from the patients’ oral cavities were Gram-negative bacteria, and 34.6% were Gram-positive bacteria. Among the patient group isolates (n = 55), the most prevalent organism was <i>Pseudomonas</i> spp. (30;54.54%). Others were <i>Klebsiella</i> spp. (27;49.09%), <i>Staphylococcus</i> spp. (24;43.63%), <i>E. coli</i> (14;25.45%), <i>Streptococcus</i> spp. (14;25.45%), <i>Proteus</i> spp. (12;21.8%) and <i>Enterococcus</i> spp. (6;10.90%). Both Gram-positive and Gram-negative microbes from the patient group have shown high resistance to the commonly used antibiotics. In the control group (n = 50), the most prevalent organism was <i>Staphylococcus</i> spp. (15;30%). Other organisms were <i>Streptococcus</i> spp. (6;12%), <i>Klebsiella</i> spp. (11;22%), <i>E. coli</i> (3;6%), <i>Streptococcus</i> spp. (14;25.45%), <i>Pseudomonas</i> spp. (8;16%). The microbes of the control group showed less resistance to the antibiotics and rather showed sensitivity to them. <b>Conclusion:</b> The study revealed a high prevalence of multi-drug-resistant opportunistic microbes on immune-compromised oral cancer patients compared to microbes isolated from healthy people’s oral cavity.展开更多
Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms i...Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms in Zhejiang Province,China,were investigated.A total of 215 isolates were identified as Escherichia coli(64.65%),Klebsiella pneumoniae(12.09%),Proteus mirabilis(10.23%),Salmonella(8.84%),and Enterobacter cloacae(4.19%).Meanwhile,all isolates were resistant to at least two antibiotics.Most isolates carried tet(A)(85.12%),blaTEM(78.60%)and sul1(67.44%)resistance genes.Gene co-occurrence analysis showed that the resistance genes were associated with IS26 and integrons.A conjugative IncFII plasmid pSDM004 containing all the above MGEs was detected in Proteus mirabilis isolate SDM004.This isolate was resistant to 18 antibiotics and carried the blaNDM-5 gene.MGEs,especially plasmids,are the primary antibiotic resistance gene transmission route in duck farms.These findings provide a theoretical basis for the rational use of antibiotics in farms which are substantial for evaluating public health and food safety.展开更多
Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully...Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.展开更多
Objective:To study the ecology of antibiotic resistant bacteria with emphasis on sucrose negative vibrios in water and sediments samples of traditional shrimp farming system(bhery)in West Bengal,India.Methods:The vibr...Objective:To study the ecology of antibiotic resistant bacteria with emphasis on sucrose negative vibrios in water and sediments samples of traditional shrimp farming system(bhery)in West Bengal,India.Methods:The vibrios were isolated from traditional shrimp farm samples on thiosulphate citrate bile salt sucrose agar and sucrose negative bacterial strains were used as biomarkers to assess the frequency of antibiotic resistance.Results:The incoming water brought presumptive vibrios ranging from 5.50×10^(1)to 1.00×10^(3)mL in to the bhery,and there appeared to build up vibrios in the culture system with days of culture,as there was about 9 fold increase in vibrios.The levels of vibrios were observed to be moderately higher in outlet water and ranged between 4.15×10^(2)and 4.15x10^(3)mL.The counts of vibrios in pond sediment was found to be 1.00x10^(2)-4.90×10^(3)g;while in inlet(2.00×10^(2)-4.20×10^(4)g)and outlet(3.00×10^(2)-6.85×10^(3)g)their levels were observed to be higher than the pond sediment.Thirteen different Vibrio species were encountered in traditional shrimp culture system and all vibrios were sensitive to chloramphenicol,followed by ciprofloxacin and gatifloxacin(98.24%),gentamicin(95.61%)and other antibiotics.The multiple antibiotic resistance(MAR),i.e.,resistance to at least two antibiotics,was noticed among 43.85%of the sucrose negative vibrios and 41.86%of the sucrose negative non--vibrios.All vibrios harveyi strains exhibited MAR.Although no antibiotic was used in the bhery,the prevalence of MAR in 44%of the sucrose negative vibrios and nonvibrios is a cause of concern.The MAR index was higher in inlet water and sediment samples.The MAR observed in biomarker strains of pond water and sediment(40%)was comparable to those of inlet samples,thus confirming the fact that incoming water was the major source of antibiotic resistant bacteria.Conclusions:It seems that the shrimp culture in bhery does not favour the proliferation and spread of antibiotic resistant bacteria.展开更多
BACKGROUND Liver transplant(LT)recipients are susceptible to carbapenem-resistant Klebsiella pneumoniae(CRKP)infections.Comprehensive research addressing the incidence,timing,infection sites,resistance patterns,treatm...BACKGROUND Liver transplant(LT)recipients are susceptible to carbapenem-resistant Klebsiella pneumoniae(CRKP)infections.Comprehensive research addressing the incidence,timing,infection sites,resistance patterns,treatment options,and associated risk factors among LT recipients with CRKP is now lacking.AIM To assess the incidence,resistance,therapy,and risk factors of CRKP infections post-LT,and to evaluate the impact of them on prognosis.METHODS A retrospective study was conducted,including 430 consecutive patients who underwent LT between January 2015 and June 2023.This study aimed to investigate the risk factors for CRKP infections and their influence on outcomes using logistic regression analysis.RESULTS Among the 430 patients who underwent LT,20(4.7%)experienced at least one documented CRKP infection within 3 months post-transplantation.The median time from LT to the onset of CRKP infections was 6.5 days.The lungs and bloodstream were the most common sites of CRKP infections.CRKP isolates were relatively susceptible to ceftazidime/avibactam(93.7%),polymyxin B(90.6%),and tigecycline(75.0%)treatment.However,all isolates were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin treatment.Recipients with CRKP infections had a mortality rate of 35%,the rate was 12.5%for those receiving ceftazidime/avibactam therapy.Multivariate analysis identified female sex[odds ratio(OR)=3.306;95%confidence interval(CI):1.239-8.822;P=0.017],intraoperative bleeding≥3000 mL(OR=3.269;95%CI:1.018-10.490;P=0.047),alanine aminotransferase on day 1 post-LT≥1500 U/L(OR=4.370;95%CI:1.686-11.326;P=0.002),and post-LT mechanical ventilation(OR=2.772;95%CI:1.077-7.135;P=0.035)as significant variables associated with CRKP.CRKP infections were related to an intensive care unit length(ICU)of stay≥7 days and 6-month all-cause mortality post-LT.CONCLUSION CRKP infections were frequent complications following LT,with poor associated outcomes.Risk factors for post-LT CRKP infections included female sex,significant intraoperative bleeding,elevated alanine aminotransferase levels,and the need for mechanical ventilation.CRKP infections negatively impacted survival and led to prolonged ICU stays.展开更多
文摘This study was conducted to isolate and identify antibiotic resistant bacteria in fresh tomato sold in three different local markets of Dhaka city. On an average 〉 5.0 log CFU/g of natural microbial populations and coliform bacteria was present in the samples. Prevalence of Salmonella spp., E. coli, Listeria spp., and Yersinia spp., were recorded through cultivation dependent assay of tomato samples of different markets. Almost all of the isolates were uniformly resistant to rifampicin, erythromycin, clindamycin and oxacillin （100%）, vancomycin （93%）, amoxicillin （87%）, whereas 60% of the isolates were found to be resistant to ampicillin and cephalexin. Antibiotic sensitivity test of the presumptive E. coli and Salmonella spp. and corresponding plasmid profiling indicated a correlation of plasmid mediated multidrug resistance （MDR） of these environmental bacteria. Washing with sanitizing agents such as acidified sodium chlorite （ASC） and 200 ppm chlorinated water was able to reduce _〈 2.0 log CFU/g of natural microflora and coliform bacteria. In contrast, ASC was able to reduce 〈 2.0 log CFU/g of other food borne pathogens and, chlorinated water was able to reduce up to undetectable level. Therefore, washing of tomato with 200 ppm chlorinated water could be useful in reducing the pathogen populations on tomatoes.
文摘Biofilms are dense bacterial colonies, derived from microbially derived sessile community, networked within a polysaccharide matrix with a distinct architecture that has the attachment potential to both alive and abiotic surfaces. <i>Pseudomonas aeruginosa</i> is a model biofilm forming microorganism associated with remarkable morbidity and mortality rate due to emergence of antibiotic resistant pathogenic bacteria. Moreover, <i>Pseudomonas aeruginosa</i> originating from a biofilm is more resistant to a wide range of antibiotics than the planktonic bacteria. This research was planned to develop a comparative study of the biofilm production between potential, antimicrobial resistance of <i>Pseudomonas aeruginosa</i> isolated from mature environmental biofilm and clinical strain of the same species that did not derive from biofilm. It was observed that the <i>Pseudomonas aeruginosa</i> from environmental isolates were resistant to 15 prominent antibiotics, while clinical strain was comparatively resistant to only few of them. A confirmatory analysis of biofilm formation and antibiotic resistance pattern of these two groups of organisms was checked by 96-well microtiter plate and the disc diffusion method respectively. Finally, the results portrayed that the environmental strains with high drug resistance, potentially formed a considerable amount of biofilm in the period of a week whereas;clinical stains formed a negligible amount of biofilm within the same time frame.
基金Fundação de Amparo a Pesquisa do Estado de São Paulo(FAPESP)and the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),São Paulo,Brazil for PhD scholarship(Process N°.141086/2015-7)financial support(Process No.870243/1997-7).
文摘The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.
基金Supported by the National Natural Science Foundation of China(No.31100089)Scientific Research Foundation of the Education Department of Sichuan Province(No.11ZB102)the Talent Project of Sichuan University of Science&Engineering(No.2011RC12)
文摘[Objective]This study aimed to investigate the mutations of OmpF from an isolated antibiotic resistant Escherichia coli strain.[Methods]The mutant OmpF（mOmpF）from antibiotic resistant E.coli was amplified by PCR with Pfu DNA polymerase and ligated into the expression vector pET28a.Subsequently,the expression vector pET28-mOmpF was sequenced and analyzed by DNAMAN software and Swiss-Model online.[Result]Sequence analysis revealed that the open reading fragment of mOmpF was 903 bp long,which was mutated dramatically compared to that of the 1 020 bp long model OmpF.The DNA sequence shared only54.5%homology with OmpF.mOmpF was 44.6%identical to that of OmpF.Protein structure predication and analysis through Swiss-Model online suggested that the structure of mOmpF changed dramatically compared to OmpF.[Conclusion]The present study provided basis for further analyzing the relationships between the structure and functions of mOmpF from antibiotic resistant E.coli.
基金the financial support provided by University of Salerno through FARB2014(Monitoraggio e modellazione dell'andamento dei batteri resistenti agli antibiotici nei corpiidrici)
文摘The fate of indigenous surface-water and wastewater antibiotic resistant bacteria in a mild slope stream simulated through a hydraulic channel was investigated in outdoor experiments.The effect of（i） natural（dark） decay,（ii） sunlight,（iii） cloudy cover,（iv） adsorption to the sediment,（v） hydraulic conditions,（vi） discharge of urban wastewater treatment plant（UWTP）effluent and（vii） bacterial species（presumptive Escherichia coli and enterococci） was evaluated.Half-life time（T1/2） of E. coli under sunlight was in the range 6.48–27.7 min（initial bacterial concentration of 10^5 CFU/mL） depending on hydraulic and sunlight conditions. E. coli inactivation was quite similar in sunny and cloudy day experiments in the early 2 hr, despite of the light intensity gradient was in the range of 15–59 W/m^2; but subsequently the inactivation rate decreased in the cloudy day experiment（T1/2= 23.0 min） compared to sunny day（T1/2= 17.4 min）. The adsorption of bacterial cells to the sediment（biofilm） increased in the first hour and then was quite stable for the remaining experimental time. Finally, when the discharge of an UWTP effluent in the stream was simulated, the proportion of indigenous antibiotic resistant E. coli and enterococci was found to increase as the exposure time increased, thus showing a higher resistance to solar inactivation compared to the respective total populations.
基金supported by Guangdong Basic and Applied Basic Research Foundation(2024A1515030201,2022A1515010197)the National Natural Science Foundation of China(41807476,42377363,42177253)Guangzhou Science and Technology Project of China(Basic and Applied Basic Research project)(202102020892).
文摘In this study,bismuth ferrite(BiFeO_(3),BFO)catalysts doped with different contents of peanut shell biochar(BC)were prepared and used in the removal of antibiotic-resistant bacteria(ARB)by peroxymonosulfate(PMS)activation from wastewater.The PMS(0.03 mM)/5%BC-BFO(0.5 g L^(−1))system removed 1.92 log ARB within 10 min of reaction at a reaction rate of 0.4401 min^(−1).Raman spectra analysis revealed that 5%BC-BFO exhibited more defects and oxygen vacancies(Ov),which provided active sites for PMS activation to generate SO_(4)^(⋅−),O_(2)^(⋅−),and^(1)O_(2),thereby promoting ARB inactivation.The oxidation of PMSO to PMSO₂suggests that high-valent iron-oxo species may also be involved in the inactivation of ARB.The PMS/5%BC-BFO system caused oxidative damage to the ARB cell membrane,increasing its permeability from 4.34%to 46.00%.Simultaneously,it triggered the activation of bacterial self-defense mechanisms and a cascade reaction,leading to the upregulation of intracellular reactive oxygen species(ROS)levels(rising from 6.34%to 62.90%),ultimately resulting in ARB inactivation.In addition,the ARB removal under PMS activation by the fourth recycled 5%BC-BFO catalyst was 62.6%of that by the fresh 5%BC-BFO.In summary,this study proposes a low-cost and easily synthesized novel catalyst for the efficient ARB removal from wastewater.
基金Supported by the Industrial Technological Initiation Scholarship of National Council for Scientific and Technological Development,CNPq,Brazil,No.0932204294929829 and No.7414780530977345the Scientific Initiation Scholarship Programme(PIBIC)of National Council for Scientific and Technological Development,CNPq,Brazil,No.5763023359532159,No.6472982965854452,and No.7340128440641417+2 种基金the Scientific Initiation Scholarship Programme(PIBIC)of Bahia State Research Support Foundation,FAPESB,Brazil,No.19.573.301.5418the PERMANECER Programme of Pro-Rectory of Student Assistance at Federal University of Bahia,No.R8EZ-4V4W-6LQX-5LC8the CNPq Research Productivity Fellow,No.4357511882624145.
文摘Recent studies have shown a noticeable increase in global Helicobacter pylori(H.pylori)resistance,with clarithromycin resistance surpassing 15%in various areas.However,inadequate epidemiological monitoring,especially in developing countries,and the absence of uniform testing methods lead to discrepancies between regions and a possible underestimation of resistance levels.The complexity of treating H.pylori is driven by its highly dynamic genome,which is prone to frequent mutations contributing to phenotypical resistance.The usual course of action in empirical treatment involves using a combination of various drugs simultaneously,leading to significant resistance selection pressure and potential side effects.The emergence of H.pylori strains resistant to multiple drugs is closely tied to failures in first-line treatment,highlighting the need to prevent further resistance by using optimal initial empirical therapy or regimens guided by antibiotic susceptibility testing,requiring a collection of mixed samples and multiple isolates for accurate assessment.The emergence of new treatments like potassium-competitive acid blockers offers a hopeful approach to decrease antimicrobial usage while still ensuring effectiveness in comparison to traditional therapies with proton pump inhibitors.Additionally,the use of probiotics is under investigation to identify specific strains and formulations that may mitigate therapy-associated adverse effects.
基金supported by the State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology) (No.2022TS13)the key projects of National Natural Science Foundation of China (No.2019YFC0408503)the Key Research Program of Wuhan (No.2022022202015015)。
文摘Antibiotic resistance genes(ARGs) are recognized as a primary threat to the sustainability of environment and human health in the 21^(st) century.Nanomaterials(NMs) have attracted substantial attention due to their unique dimensions and structures.Unfortunately,emerging evidence suggests that NMs may facilitate the transmission of ARGs.It is crucial to elucidate how NMs affect the evolution and dissemination of ARGs.The current review comprehensively examines the role of NMs in the widespread transmission of ARGs in aquatic environments and the underlying mechanisms involved in the process.It aims to clarify the effects and mechanisms of NMs on the horizontal gene transfer processes that are associated with ARGs,including the enhancement of cell membrane permeability,the formation of nanopores on membranes,promotion of mutagenesis,and the generation of reactive oxygen species(ROSs).Furthermore,the trade-off between the removal of ARGs and horizontal transfer has been elucidated.The review aspires to guide future research directions,advance knowledge on the implications of NMs in the field of ARGs' transmission,and provide a theoretical foundation for the development of safer and more effective applications of NMs.
文摘Objective:To analyse the prevalence of serotypes,antibiotic resistance,and virulence genes of Group B Streptococcus(GBS)strains isolated from pregnant women at 35-37 weeks of gestation in Ho Chi Minh City,Vietnam,from January 2022 to January 2023.Methods:GBS strains were isolated through selective culture methods and confirmed by PCR.Serotyping,virulence gene detection,and antibiotic susceptibility testing were performed using PCR,gel electrophoresis techniques and Kirby-Bauer test.Results:Totally,61 GBS isolated from 300 participants have been identified including seven GBS serotypes(Ⅰa,Ⅰb,Ⅱ,Ⅲ,Ⅳ,Ⅴ,andⅥ).SerotypesⅦ,Ⅷ,andⅨwere not detected in the study population.Antibiotic resistance patterns varied:13.1%of isolates were fully susceptible,while the majority showed multi-drug resistance,with 34.4%resistant to three antibiotics.SerotypeⅠa demonstrated high susceptibility(35.7%),while serotypeⅢshowed extensive resistance,with 87.5%being resistant to at least three antibiotics.All strains are susceptible to vancomycin andβ-lactams susceptibility also remained high,but resistance to clindamycin,erythromycin,and tetracycline was high(>65%).The virulence genes scpB,cylB,fbsB,and cfb were highly prevalent(90%-100%),indicating their potential for vaccine and diagnostic development.Conclusions:Our findings provide valuable insights into GBS serotypes,resistance,and virulence factors,contributing to community monitoring,preventive measures,diagnostics,and vaccine development.However,the limited sample size necessitates further research.
基金Supported by Special Fund for Ocean and Fisheries Science Technology and Industrial Development of Guangdong Province(A201508A05)~~
文摘In this study, bacteriophage of an antibiotic-resistant Escherchia coil strain isolated from feces of chicken was isolated. Its host range was determined by the method of spotting sample on monolayer agar, and its lysis titer, optimal multiplicity of infection （MOI）, temperature tolerance and pH tolerance were determined by the double-layer agar plate method. The results showed that the bacteriophage had a broad host range. The biological assay demonstrated that two strains of E. coil were fully lysed and one strain of E. coil was weakly lysed by the bacteriophage. The lysis titer and MOI of the bacteriophage were 1.20×10^8 PFU/ml and 1, respec- tively. Under the optimum temperature of 40℃, the Jysis titer of the bacteriophage reached 8.90×10^9 PFU/ml; however, the bacteriophage lost its infectivity at the tem- perature of 80℃. In the pH range of 5-11, the lysis titer of the bacteriophage ranged from10^6 to 10^9 PFU/mI. Under the condition of pH 4 and 12, the bacterio- phage was invalid.
文摘Antibiotic resistant bacteria pass between humans, between animals and between humans and animals in both directions, the use of antibiotics in poultry has contributed to multiple antibiotic resistant in pathogenic bacteria and use of two antibiotics might prevent the emergence of resistance to either. In this study, synergistic effect of combined antibiotics against multidrug resistant human pathogenic bacterial isolates from poultry droppings in Akure, Nigeria was examined. Collection of samples, isolation and identification of bacteria were carried out using standard microbiological method, antibiotic sensitivity test was performed by disc diffusion method and zone of inhibition was used to interpret the sensitivity test as resistant, susceptible or intermediate while combined effects of two antibiotics were investigated by macrobroth dilution and checkerboard assay methods while the synergetic effects of combined antibiotics were calculated using Fractional Inhibitory Concentration (FIC) and percentage synergistic interaction was calculated. All the ten (10) species of bacterial isolates were multidrug resistant and are less resistant to ofloxacin. The highest percentage synergistic interactions observed were Ofloxacin + Amoxicillin (90%), Ciprofloxacin + Amoxicillin (90%), Tetracycline + Amoxicillin (70%), Tetracycline + Augmentin (80%), Cotrimoxazol + Amoxicillin (50%), Cotrimoxazol + Augmentin (70%), Chloramphenicol + Amoxicillin (70%) and Chloramphenicol + Augmentin (80%). Poultry droppings is a potential source of human pathogenic bacteria, high frequency of multiple antibiotic resistance bacteria observed in this study is of great treat to man as this may cause the treatment of infection caused by these bacteria to be difficult. Combination of beta-lactam antibiotic with fluoroqunolones, tetracycline, Chloramphenicol and Cotrimoxazole was synergetic and this will reduce dose related toxicity and prevent resistance to single antibiotic.
基金supported by the National Science and Technology Major Projects for Water Pollution Control and Treatment(No.2017ZX07201-003)the Science and Technology Program of Zhejiang Province(No.LQ19E080023)the Zhejiang Public welfare technology research program(No.GG21E080021)。
文摘Once contaminate the drinking water source,antibiotic resistance genes(ARGs)will propagate in drinking water systems and pose a serious risk to human health.Therefore,the drinking water treatment processes(DWTPs)are critical to manage the risks posed by ARGs.This study summarizes the prevalence of ARGs in raw water sources and treated drinking water worldwide.In addition,the removal efficiency of ARGs and related mechanisms by different DWTPs are reviewed.Abiotic and biotic factors that affect ARGs elimination are also discussed.The data on presence of ARGs in drinking water help come to the conclusion that ARGs pollution is prevalent and deserves a high priority.Generally,DWTPs indeed achieve ARGs removal,but some biological treatment processes such as biological activated carbon filtration may promote antibiotic resistance due to the enrichment of ARGs in the biofilm.The finding that disinfection and membrane filtration are superior to other DWTPs adds weight to the advice that DWTPs should adopt multiple disinfection barriers,as well as keep sufficient chlorine residuals to inhibit re-growth of ARGs during subsequent distribution.Mechanistically,DWTPs obtain direct and inderect ARGs reduction through DNA damage and interception of host bacterias of ARGs.Thus,escaping of intracellular ARGs to extracellular environment,induced by DWTPs,should be advoided.This review provides the theoretical support for developping efficient reduction technologies of ARGs.Future study should focus on ARGs controlling in terms of transmissibility or persistence through DWTPs due to their biological related nature and ubiquitous presence of biofilm in the treatment unit.
基金supported by the U.S.Department of Agriculture NIFA Award(No.2018-68003-27467).
文摘Manure application as fertilizer can increase environmental exposure risk,as antibiotics,antibiotic resistance bacteria(ARB),and antibiotic resistant genes(ARGs)can be transmitted to agricultural fields,and adjacent natural systems.Understanding how specific antibiotics and ARGs respond within different manure fractions during on-farm management is limited.The study objective was to conduct a mass flow analysis determining the fate of antibiotic resistance factors(antibiotics,ARGs,and ARB)through solid-liquid separation,with the solid fraction continuing through a bedding recovery unit(BRU)via high temperature rotary composting for use of the manure solids as dairy cow bedding.The results show that most of the manure mass containing the antibiotic resistance factors went untreated following solid-liquid separation,with 95%of the mass leaving the separator as a liquid and pumped to a storage lagoon for field application and 5%proceeding to BRU processing.The tetracyclines and tulathromycin sorbed to the manure solids,while the beta lactams,ampicillin,and benzylpenicilloic acid were only found in the liquid fraction.The removal of antibiotic residuals during the BRU composting was insignificant,yet 40%-73%of the antibiotics were in the liquid fraction.The BRU composting was 100%effective in removing the ARB examined.Five of the eight ARGs(intl1,sul1,tetQ,tetX,and tetM)had significant reduction(>95%)following the BRU composting treatment.While the three other ARGs(tetW,ermB,and bla2)remained constant despite treatment.This study highlighted the importance of examining manure management from a mass balance perspective and understanding antibiotic resistance risk factors.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (No. 2012-0003505)Korea Ministry of Environment as "Global Top Project" (No. GT-11-B-01-005-1)
文摘This study compared three different disinfection processes （chlorination, E-beam, and ozone） and the efficacy of three oxidants （H202, S2O8-, and peroxymonosulfate （MPS）） in removing antibiotic resistant bacteria （ARB） and antibiotic resistance genes （ARGs） in a synthetic wastewater. More than 30 mg/L of chlorine was needed to remove over 90% of ARB and ARG. For the E-beam method, only 1 dose （kGy） was needed to remove ARB and ARG, and ozone could reduce ARB and ARG by more than 90% even at 3 mg/L ozone concentration. In the ozone process, CT values （concentration × time） were compared for ozone alone and combined with different catalysts based on the 2-log removal of ARB and ARG. Ozone treatment yielded a value of 31 and 33 （mg·min）/L for ARB and ARGs respectively. On the other hand, ozone with persulfate yielded 15.9 and 18.5 （mg.min）/L while ozone with monopersulfate yielded a value of 12 and 14.5 （mg·min）/L. This implies that the addition of these catalysts significantly reduces the contact time to achieve a 2-log removal, thus enhancing the process in terms of its kinetics.
基金DK was partially supported by grants from CONICET, ANPCyT and SECYTUNC.
文摘This paper presents a compartmental model for bacterial infections in a population distributed over a network of individuals.Within each node,individuals interact,bacteria can be transmitted and the disease may be spread;moreover,the acquisition of bacterial antibiotic resistance is considered.In addition,nodes are connected through weighted edges,and consequently individuals from different nodes may interact.As a result,the infection may be propagated over the network.We perform an analysis on this propagation as well as numerical simulations in order to illustrate the validity of the model.
文摘<b>Introduction:</b> Oral cancer is the third most prominent type of cancer in Bangladesh. During or after oral cancer treatment, immune-compromised cancer patients may be susceptible to an infection by multi-drug-resistant opportunistic microbes. This study aims to identify the prevalent microorganisms from the infected site of oral cancer patients and observe their antibiotic susceptibility pattern. <b>Materials and Methods:</b> Clinical samples were collected from the infected sites of oral cancer patients and healthy people. The swabs collected were placed on nutrient agar slant, then incubated for 24 hours at 37ºC. Bacteria from the slant were inoculated in several selective media (Mannitol Salt Agar Media, KF Streptococcus Agar media, Cetrimide Agar, Eosin Methylene Blue Agar). Several biochemical tests identified opportunistic microorganisms. Finally, the antibiotic susceptibility test was performed by the Kirby Bauer disc diffusion method. <b>Results:</b> The study found that 65.4% of microbes isolated from the patients’ oral cavities were Gram-negative bacteria, and 34.6% were Gram-positive bacteria. Among the patient group isolates (n = 55), the most prevalent organism was <i>Pseudomonas</i> spp. (30;54.54%). Others were <i>Klebsiella</i> spp. (27;49.09%), <i>Staphylococcus</i> spp. (24;43.63%), <i>E. coli</i> (14;25.45%), <i>Streptococcus</i> spp. (14;25.45%), <i>Proteus</i> spp. (12;21.8%) and <i>Enterococcus</i> spp. (6;10.90%). Both Gram-positive and Gram-negative microbes from the patient group have shown high resistance to the commonly used antibiotics. In the control group (n = 50), the most prevalent organism was <i>Staphylococcus</i> spp. (15;30%). Other organisms were <i>Streptococcus</i> spp. (6;12%), <i>Klebsiella</i> spp. (11;22%), <i>E. coli</i> (3;6%), <i>Streptococcus</i> spp. (14;25.45%), <i>Pseudomonas</i> spp. (8;16%). The microbes of the control group showed less resistance to the antibiotics and rather showed sensitivity to them. <b>Conclusion:</b> The study revealed a high prevalence of multi-drug-resistant opportunistic microbes on immune-compromised oral cancer patients compared to microbes isolated from healthy people’s oral cavity.
基金supported by the National Natural Science Foundation of China(32172188)Science and Technology Cooperation Project of ZheJiang Province(2023SNJF058-3)。
文摘Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms in Zhejiang Province,China,were investigated.A total of 215 isolates were identified as Escherichia coli(64.65%),Klebsiella pneumoniae(12.09%),Proteus mirabilis(10.23%),Salmonella(8.84%),and Enterobacter cloacae(4.19%).Meanwhile,all isolates were resistant to at least two antibiotics.Most isolates carried tet(A)(85.12%),blaTEM(78.60%)and sul1(67.44%)resistance genes.Gene co-occurrence analysis showed that the resistance genes were associated with IS26 and integrons.A conjugative IncFII plasmid pSDM004 containing all the above MGEs was detected in Proteus mirabilis isolate SDM004.This isolate was resistant to 18 antibiotics and carried the blaNDM-5 gene.MGEs,especially plasmids,are the primary antibiotic resistance gene transmission route in duck farms.These findings provide a theoretical basis for the rational use of antibiotics in farms which are substantial for evaluating public health and food safety.
基金This work was financially sup-ported by the National Natural Science Foundation of China(NSFC Nos:22171212,21771140,51771138,51979194)International Corporation Project of Shanghai Committee of Science and Technology by China(No.21160710300)International Exchange Grant(IEC/NSFC/201078)through Royal Society UK and NSFC.
文摘Trifunctional Cu-mesh/Cu_(2)O@FeO nanoarrays heterostructure is designed and fabricated by integrating CuCu_(2)O@FeO nanoarrays onto Cu-mesh(CM)via an in situ growth and phase transformation process.It is successfully applied to efficiently mitigate the antibiotic pollution,including degradation of antibiotics,inactivation of antibiotic-resistant bacteria(ARB),and damage of antibiotics resistance genes(ARGs).Under visible-light irradiation,CM/CuCu_(2)O@FeO nanoarrays exhibit a superior degradation efficiency on antibiotics(e.g.,up to 99%in 25 min for tetracycline hydrochloride,TC),due to the generated reactive oxygen species(ROS),especially the dominant·O^(2−).It can fully inactivate E.coli(HB101)with initial number of~108 CFU mL^(−1) in 10 min,which is mainly attributed to the synergistic effects of 1D nanostructure,dissolved metal ions,and generated ROS.Meanwhile,it is able to damage ARGs after 180 min of photodegradation,including tetA(vs TC)of 3.3 log 10,aphA(vs kanamycin sulfate,KAN)of 3.4 log 10,and tnpA(vs ampicillin,AMP)of 4.4 log 10,respectively.This work explores a green way for treating antibiotic pollution under visible light.
基金supported by Department of Aquatic Animal Health,Faculty of Fishery Sciences,West Bengal University of Animal and Fishery Sciences,West Bengal,India.(FFS/Adm-21/323)
文摘Objective:To study the ecology of antibiotic resistant bacteria with emphasis on sucrose negative vibrios in water and sediments samples of traditional shrimp farming system(bhery)in West Bengal,India.Methods:The vibrios were isolated from traditional shrimp farm samples on thiosulphate citrate bile salt sucrose agar and sucrose negative bacterial strains were used as biomarkers to assess the frequency of antibiotic resistance.Results:The incoming water brought presumptive vibrios ranging from 5.50×10^(1)to 1.00×10^(3)mL in to the bhery,and there appeared to build up vibrios in the culture system with days of culture,as there was about 9 fold increase in vibrios.The levels of vibrios were observed to be moderately higher in outlet water and ranged between 4.15×10^(2)and 4.15x10^(3)mL.The counts of vibrios in pond sediment was found to be 1.00x10^(2)-4.90×10^(3)g;while in inlet(2.00×10^(2)-4.20×10^(4)g)and outlet(3.00×10^(2)-6.85×10^(3)g)their levels were observed to be higher than the pond sediment.Thirteen different Vibrio species were encountered in traditional shrimp culture system and all vibrios were sensitive to chloramphenicol,followed by ciprofloxacin and gatifloxacin(98.24%),gentamicin(95.61%)and other antibiotics.The multiple antibiotic resistance(MAR),i.e.,resistance to at least two antibiotics,was noticed among 43.85%of the sucrose negative vibrios and 41.86%of the sucrose negative non--vibrios.All vibrios harveyi strains exhibited MAR.Although no antibiotic was used in the bhery,the prevalence of MAR in 44%of the sucrose negative vibrios and nonvibrios is a cause of concern.The MAR index was higher in inlet water and sediment samples.The MAR observed in biomarker strains of pond water and sediment(40%)was comparable to those of inlet samples,thus confirming the fact that incoming water was the major source of antibiotic resistant bacteria.Conclusions:It seems that the shrimp culture in bhery does not favour the proliferation and spread of antibiotic resistant bacteria.
文摘BACKGROUND Liver transplant(LT)recipients are susceptible to carbapenem-resistant Klebsiella pneumoniae(CRKP)infections.Comprehensive research addressing the incidence,timing,infection sites,resistance patterns,treatment options,and associated risk factors among LT recipients with CRKP is now lacking.AIM To assess the incidence,resistance,therapy,and risk factors of CRKP infections post-LT,and to evaluate the impact of them on prognosis.METHODS A retrospective study was conducted,including 430 consecutive patients who underwent LT between January 2015 and June 2023.This study aimed to investigate the risk factors for CRKP infections and their influence on outcomes using logistic regression analysis.RESULTS Among the 430 patients who underwent LT,20(4.7%)experienced at least one documented CRKP infection within 3 months post-transplantation.The median time from LT to the onset of CRKP infections was 6.5 days.The lungs and bloodstream were the most common sites of CRKP infections.CRKP isolates were relatively susceptible to ceftazidime/avibactam(93.7%),polymyxin B(90.6%),and tigecycline(75.0%)treatment.However,all isolates were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin treatment.Recipients with CRKP infections had a mortality rate of 35%,the rate was 12.5%for those receiving ceftazidime/avibactam therapy.Multivariate analysis identified female sex[odds ratio(OR)=3.306;95%confidence interval(CI):1.239-8.822;P=0.017],intraoperative bleeding≥3000 mL(OR=3.269;95%CI:1.018-10.490;P=0.047),alanine aminotransferase on day 1 post-LT≥1500 U/L(OR=4.370;95%CI:1.686-11.326;P=0.002),and post-LT mechanical ventilation(OR=2.772;95%CI:1.077-7.135;P=0.035)as significant variables associated with CRKP.CRKP infections were related to an intensive care unit length(ICU)of stay≥7 days and 6-month all-cause mortality post-LT.CONCLUSION CRKP infections were frequent complications following LT,with poor associated outcomes.Risk factors for post-LT CRKP infections included female sex,significant intraoperative bleeding,elevated alanine aminotransferase levels,and the need for mechanical ventilation.CRKP infections negatively impacted survival and led to prolonged ICU stays.
