Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dyn...Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dynamic changes in soil communities,potential bacterial pathogens,and ARG profiles under various organicmaterial treatments during RSD,including distillers’grains,potato peel,peanut vine,and peanut vine combined with charcoal.Results revealed that applying diverse organic materials in RSD significantly altered bacterial community composition and diminished the relative abundance of potential bacterial pathogens(P<0.05).The relative abundance of high-risk ARGs decreased by 10.7%-30.6%after RSD treatments,the main decreased ARG subtypeswere AAC(3)_Via,dfrA1,ErmB,lnuB,aadA.Actinobacteria was the primary host of ARGs and was suppressed by RSD.Soil physicochemical properties,such as total nitrogen,soil pH,total carbon,were crucial factors affecting ARG profiles.Our findings demonstrated that RSD treatment inhibited pathogenic bacteria and could be an option for reducing high-risk ARG proliferation in soil.展开更多
The sustainable development of aquaculture industry is deeply constrained by pathogens and diseases,and traditional detection methods are difficult to adapt to the needs of intensive aquaculture due to low efficiency ...The sustainable development of aquaculture industry is deeply constrained by pathogens and diseases,and traditional detection methods are difficult to adapt to the needs of intensive aquaculture due to low efficiency and insufficient sensitivity.This article reviews the progress of rapid detection technology for aquatic pathogens based on molecular biology,immunology,biosensors,etc.,and analyzes the application value of innovative methods such as isothermal amplification and CRISPR.This technology injects core momentum into the new quality productivity of fisheries through early and precise identification of pathogens:reducing aquaculture losses to improve resource efficiency,promoting the transformation of aquaculture models to data-driven,ensuring the safety of aquatic products to enhance the competitiveness of the industry chain.The current technology has shortcomings such as lagging standardization,weak on-site anti-interference ability,and insufficient recognition of new pathogens.In the future,we need to focus on technological integration and innovation,intelligent upgrading,and standardization construction,promote technology from laboratories to industrial applications,and provide continuous support for the high-quality development of fisheries.展开更多
In order to ensure food safety,controlling foodborne pathogen contamination is of utmost importance.Growing apprehensions regarding the safety of synthetic antimicrobials,due to their adverse health effects,have promp...In order to ensure food safety,controlling foodborne pathogen contamination is of utmost importance.Growing apprehensions regarding the safety of synthetic antimicrobials,due to their adverse health effects,have prompted a search for alternative options.Plant natural products(PNPs)with antimicrobial activity are being explored as a viable alternative.Among the various antimicrobial natural products studied,plant essential oils,plant flavonoids,plant polyphenols,plant polysaccharides,and plant antimicrobial peptides have been identified as potential candidates.PNPs demonstrate a diverse array of antimicrobial mechanisms,encompassing cell wall and membrane damage,interference with genetic replication,disruption of energy metabolism,and induction of oxidative stress at the single-cell level,as well as inhibition of biofilm formation and quorum sensing at the population level.Certain PNPs have been harnessed as natural antimicrobial agents for the food preservation.The utilization of encapsulation technology proves to be an effective strategy in protecting PNPs,thereby ensuring good antimicrobial efficacy,enhanced dispersibility,and controlled release within food products.The utilization of nanoemulsions,nanoliposomes,edible packaging,electrospun nanofibers,and microcapsules formed by encapsulation has enriched the ways in which PNPs can be applied in food preservation.Although PNPs have great potential in food preservation,their widespread application in the food industry is currently constrained by factors such as production costs,safety concerns,and legal considerations.Chemical synthesis and biosynthesis pathways offer viable strategies for reducing the cost of producing PNPs,and ongoing efforts to assess safety and improve regulatory frameworks are likely to facilitate the broader adoption of PNPs in food preservation practices.This article provides an overview of the main types of PNPs with antimicrobial activity and their properties,focusing on their mechanisms of action.Additionally,it summarizes the use of PNPs in food preservation and discusses the characteristics and applications of different encapsulation technologies.Lastly,the paper briefly analyzes current limitations and proposes potential future trends for this field.展开更多
Respiratory infections are associated with high morbidity and mortality and are a major global health problem[1].Acute respiratory infections are caused by multiple respiratory pathogens,including viruses and bacteria...Respiratory infections are associated with high morbidity and mortality and are a major global health problem[1].Acute respiratory infections are caused by multiple respiratory pathogens,including viruses and bacteria.Viral-bacterial co-infections,which have become increasingly common and a global concern,can lead to substantial complications,causing higher morbidity and adverse prognosis[2].Previous studies have reported low positive detection rates of targeted pathogens related to acute respiratory infections,owing to the limited number of detected pathogens and variations in the sensitivity of diagnostic methods[3-4].Low positive detection rates may impede our understanding of respiratory pathogen characteristics and hamper the development of precise treatment and prevention strategies.展开更多
The pathogens and opinion for antibiotic treatment in adult patients with 1-14 fecal white blood cells per high power field （WBC/HPF） of acute non-bloody diarrhea remain obscure. The study attempts to clarify it. St...The pathogens and opinion for antibiotic treatment in adult patients with 1-14 fecal white blood cells per high power field （WBC/HPF） of acute non-bloody diarrhea remain obscure. The study attempts to clarify it. Stool specimens of adult patients with acute non-bloody diarrhea and stool examination showing 1-14 fecal WBC/HPF were collected for bacterial culture and viral detection. Patients included in this study were 196 cases with mean age of （37.9±17.4） years and 42.3% was women. The bacterial and viral detection rates were 63 （32.1%） and 21 （10.7%）, respectively. Of the isolated pathogens, campylobacteria was present in 14 （22.0%） samples and was the most common bacteria and calicivirus was found in 10 （47.6%） samples and was the most common virus. Based on single pathogens, 46 cases were caused by invasive pathogens, 26 cases were caused by non-invasive pathogens. The body temperature was significantly higher in feverish patients caused by invasive pathogens than those caused by non-invasive pathogens （（38.44-0.7） ℃ vs （37.74-0.4） ℃, P = 0.002）. The probability of diarrhea caused by invasive pathogens was higher in patients with T〉38.4℃ than those with T_〈38.4℃ （RR = 1.5）. When T〉38.4℃ is used as the threshold for antibiotic treatment, the misuse rate of antibiotics would decrease from 26.9% to 3.8% （P = 0.021）. So T〉38.4 ℃ may be used as a possible reference value for antibiotic treatment in adult patients with 1-14 fecal WBC/HPF of acute non-bloody diarrhea.展开更多
[Objective] The aim of this study was to purify an antimicrobial protein from a biocontrol bacterium strain K2-1 and analyze its antimicrobial activity in vitro against some typical aquatic pathogens. [Method] The ant...[Objective] The aim of this study was to purify an antimicrobial protein from a biocontrol bacterium strain K2-1 and analyze its antimicrobial activity in vitro against some typical aquatic pathogens. [Method] The antimicrobial protein was ob- tained by using ammonium sulfate precipitation and Sephadex chromatography combined with hot water bath. The antimicrobial assay was conducted by means of agar diffusion technique, using Vibrio alginolyticus, Aeromonas hydrophila, Aeromonas. Sobria, Pseudomonas fluorescens, Vibrio Parahaemolyticus, Vibrio har- veyi and Vibrio anguillarum as test bacteria. [Result] Antimicrobial protein APK2 can be derived from fermentation broth of strain K2-1 and purified to the chromatogra- phy pure level by the methods provided, the final yield of the antimicrobial compo- nent is approximately 0.08%. This antimicrobial protein had a strong antimicrobial activity against the growth of most those bacteria. [Conclusion] The results show that APK2 could be a potential alternative to replace chemical antimicrobial agent in the control and prevention of aquatic diseases.展开更多
The effects of O3/Cl2 disinfection on corrosion and the growth of opportunistic pathogens in drinking water distribution systems were studied using annular reactors （ARs）. The corrosion process and most probable num...The effects of O3/Cl2 disinfection on corrosion and the growth of opportunistic pathogens in drinking water distribution systems were studied using annular reactors （ARs）. The corrosion process and most probable number （MPN） analysis indicated that the higher content of iron-oxidizing bacteria and iron-reducing bacteria in biofilms of the AR treated with O3/Cl2 induced higher Fe304 formation in corrosion scales. These corrosion scales became more stable than the ones that formed in the AR treated with Cl2 alone. O3/Cl2 disinfection inhibited corrosion and iron release efficiently by changing the content of corrosion-related bacteria. Moreover, ozone disinfection inactivated or damaged the opportunistic pathogens due to its strong oxidizing properties. The damaged bacteria resulting from initial ozone treatment were inactivated by the subsequent chlorine disinfection. Compared with the AR treated with Cl2 alone, the opportunistic pathogens M. auium and L. pneumophila were not detectable in effluents of the AR treated with O3/Cl2, and decreased to （4.60 ± 0.14） and （3.09 ± 0.12） loglo （gene copies/g corrosion scales） in biofilms, respectively. The amoeba counts were also lower in the AR treated with O3/Cl2. Therefore, O3/Cl2 disinfection can effectively control opportunistic pathogens in effluents and biofilms of an AR used as a model for a drinking water distribution system.展开更多
The importance of pyrimidines lies in the fact that they are structural components of a broad spectrum of key molecules that participate in diverse cellular functions, such as synthesis of DNA, RNA, lipids, and carboh...The importance of pyrimidines lies in the fact that they are structural components of a broad spectrum of key molecules that participate in diverse cellular functions, such as synthesis of DNA, RNA, lipids, and carbohydrates. Pyrimidine metabolism encompasses all enzymes involved in the synthesis, degradation, salvage, interconversion and transport of these molecules. In this review, we summarize recent publications that document how pyrimidine metabolism changes under a variety of conditions, including, when possible, those studies based on techniques of genomics, transcriptomics, proteomics, and metabolomics. First, we briefly look at the dynamics of pyrimidine metabolism during nonpathogenic cellular events. We then focus on changes that pathogen infections cause in the pyrimidine metabolism of their host. Next, we discuss the effects of antimetabolites and inhibitors, and finally we consider the consequences of genetic ma- nipulations, such as knock-downs, knock-outs, and knock-ins, of pyrimidine enzymes on pyrimidine metabolism in the cell.展开更多
The emergence and prevalence of antibiotic resistance genes(ARGs) and pathogens in the environment are serious global health concern. However, information about the occurrence of ARGs and pathogens in recreational wat...The emergence and prevalence of antibiotic resistance genes(ARGs) and pathogens in the environment are serious global health concern. However, information about the occurrence of ARGs and pathogens in recreational water is still limited. Accordingly, we investigated the occurrence of six ARGs and human pathogens in three recreational lakes, and the correlations between ARGs and one mobile genetic element(intI1) were analyzed. The quantitative PCR results showed that the concentration of ARGs ranged from 4.58 × 10~0 to 5.0 × 10~5 copies/mL in water and from 5.78 × 10~3 to 5.89 × 10~8 copies/g dry weight(dw)in sediment. Sul1 exhibited the highest level among the five quantifiable ARGs. The concentrations of sul1, bla_(-TEM), and tetX exhibited significant positive correlations with intI1(p < 0.05), indicating that intI1 may be involved in their proliferation. The detection frequencies of ARGs ranged from 75%–10~0%, indicating the prevalence of these risks in this region. The concentration of Escherichia coli, Aeromonas spp., Mycobacterium avium,Pseudomonas aeruginosa, and Salmonella enterica ranged from 10~3 to 10~5 copies/10~0 mL in water and 10~4–10~6 copies/g dw in sediment. In total, 25% of the samples harbored all pathogen genes, indicating the prevalence of these pathogens in recreational lakes.Furthermore, the next-generation sequencing results showed that 68 genera of pathogens were present, among which Aeromonas, Mycobacterium, and Pseudomonas were the dominant ones in this region, posing a considerable potential health risk to public health. Overall, the widespread distribution of ARGs and pathogens underscores the need to better monitor and mitigate their propagation in recreational lakes and the associated risks to human health.展开更多
Plant pathogens have evolved numerous strategies to obtain nutritive materials from their host, and plants in turn have evolved the preformed physical and chemical barriers as well as sophisticated two-tiered immune s...Plant pathogens have evolved numerous strategies to obtain nutritive materials from their host, and plants in turn have evolved the preformed physical and chemical barriers as well as sophisticated two-tiered immune system to combat pathogen attacks. Genetically, plant resistance to pathogens can be divided into qualitative and quantitative disease resistance, conditioned by major gene（s） and multiple genes with minor effects, respectively. Qualitative disease resistance has been mostly detected in plant defense against biotrophic pathogens, whereas quantitative disease resistance is involved in defense response to all plant pathogens, from biotrophs, hemibiotrophs to necrotrophs. Plant resistance is achieved through interception of pathogen-derived effectors and elicitation of defense response. In recent years, great progress has been made related to the molecular basis underlying host--pathogen interactions. In this review, we would like to provide an update on genetic and molecular aspects of plant resistance to pathogens.展开更多
Due to increasing regulations and restrictions, there is an urgent need to develop effective alternatives to chemical-dependent fumigation control of soilborne pests and pathogens. Anaerobic soil disinfestation （ASD...Due to increasing regulations and restrictions, there is an urgent need to develop effective alternatives to chemical-dependent fumigation control of soilborne pests and pathogens. Anaerobic soil disinfestation （ASD） is one such alternative showing great promise for use in the control of soilborne pathogens and pests. This method involves the application of a carbon source, irrigation to field capacity, and covering the soil with a plastic tarp. While the mechanisms of ASD are not completely understood, they appear to be a combination of changes in the soil microbial community composition, production of volatile organic compounds, and the generation of lethal anaerobic conditions. The variety of materials and options for ASD application, including carbon sources, soil temperature, and plastic tarp type, influence the efficacy of pathogen sup- pression and disease control. Currently, both dry （e.g., rice bran） and liquid （e.g., ethanol） carbon sources are commonly used, but with different results depending on environmental conditions. While solarization is not an essential component of ASD, it can enhance efficacy. Understanding the mechanisms that mediate biological changes occurring in the soil during ASD will facilitate our ability to increase ASD efficacy while enhancing its commercial viability.展开更多
Objective Lower respiratory tract infections continue to pose a significant threat to human health. It is important to accurately and rapidly detect respiratory bacteria. To compensate for the limits of current respir...Objective Lower respiratory tract infections continue to pose a significant threat to human health. It is important to accurately and rapidly detect respiratory bacteria. To compensate for the limits of current respiratory bacteria detection methods, we developed a combination of multiplex polymerase chain reaction （PCR） and capillary electrophoresis （MPCE） assay to detect thirteen bacterial pathogens responsible for lower respiratory tract infections, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catorrholis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Mycoplasma pneumoniae, Legionella spp., Bordetella pertussis, Mycobacterium tuberculosis complex, Corynebactefium diphthefiae, and Streptococcus pyogenes. Methods Three multiplex PCR reactions were built, and the products were analyzed by capillary electrophoresis using the high-throughput DNA analyzer. The specificity of the MPCE assay was examined and the detection limit was evaluated using DNA samples from each bacterial strain and the simulative samples of each strain. This assay was further evaluated using 152 clinical specimens and compared with real-time PCR reactions. For this assay, three nested-multiplex-PCRs were used to detect these clinical specimens. Results The detection limits of the MPCE assay for the 13 pathogens were very low and ranged from 10-7 to 10-2 ng/μL. Furthermore, analysis of the 252 clinical specimens yielded a specificity ranging from 96.5%-100.0%, and a sensitivity of 100.0% for the 13 pathogens. Conclusion This study revealed that the MPCE with high specificity and sensitivity. This assay survey of respiratory pathogens. assay is a rapid, reliable, and high-throughput method has great potential in the molecular epidemiological.展开更多
Objective:To determine the prevalence and antimicrobial resistance rates of nosocomial pathogens isolated from cancer patients and hospital environments.Methods:A descriptive cross-sectional study was conducted betwee...Objective:To determine the prevalence and antimicrobial resistance rates of nosocomial pathogens isolated from cancer patients and hospital environments.Methods:A descriptive cross-sectional study was conducted between December 2010 to May 2013 at Radiation and Isotopes Centre of Khartoum,Sudan.A total of 1 503 samples(505 clinical and 998 environmental)were examined.Isolates were identified,and their antimicrobial susceptibility was determined using standard laboratory procedures.Results:Out of 505 clinical samples,nosocomial pathogens were found as 48.1%.Among hospital environment samples,bacterial contaminants were detected in 29.7%of samples.The main microorganisms recovered from cancer patients were Proteus spp.(23.5%),Escherichia coli(22.2%),Pseudomonas aeruginosa(P.aeruginosa)(21.0%)and Staphylococcus aureus(20.2%).The most frequent isolates from hospital environments were Bacillus spp.(50.0%),Staphylococcus aureus(14.2%)and P.aeruginosa(11.5%).The proportions of resistance among Gram-negative pathogens from cancer patients were high for ampicillin,cefotaxime,ceftazidime and ceftriaxone.Moderate resistance rates were recorded to ciprofloxacin,such as 51.0%for P.aeruginosa,21.7%for Klebsiella pneumoniae and 55.5%for Escherichia coli.Except Klebsiella,there were no significant differences(P0.05)of resistance rates between Gram-negative isolates from cancer patients to those from the hospital environments.The proportions of extended-spectrum b-lactamase producing isolates from cancer patients were not differ significantly(P=0.763)from those collected from the hospital environments(49.2%;91/185 vs.47%;32/68).Conclusions:The prevalence of nosocomial infection among cancer patients was high(48.1%)with the increasing of antimicrobial resistance rates.Hospital environments are potential reservoirs for nosocomial infections,which calls for intervention program to reduce environmental transmission of pathogens.展开更多
Spontaneous bacterial peritonitis(SBP) is the most typical infection observed in cirrhosis patients. SBP is responsible for an in-hospital mortality rate of approximately 32%. Recently, pattern changes in the bacteria...Spontaneous bacterial peritonitis(SBP) is the most typical infection observed in cirrhosis patients. SBP is responsible for an in-hospital mortality rate of approximately 32%. Recently, pattern changes in the bacterial flora of cirrhosis patients have been observed, and an increase in the prevalence of infections caused by multi-resistant bacteria has been noted. The wide-scale use of quinolones in the prophylaxis of SBP has promoted flora modifications and resulted in the development of bacterial resistance. The efficacy of traditionally recommended therapy has been low in nosocomial infections(up to 40%), and multi-resistance has been observed in up to 22% of isolated germs in nosocomial SBP. For this reason, the use of a broad empirical spectrum antibiotic has been suggested in these situations. The distinction between community-acquired infectious episodes, healthcare-associated infections, or nosocomial infections, and the identification of risk factors for multi-resistant germs can aid in the decision-making process regarding the empirical choice of antibiotic therapy. Broad-spectrum antimicrobial agents, such as carbapenems with or without glycopeptides or piperacillin-tazobactam, should be considered for the initial treatment not only of nosocomial infections but also of healthcare-associated infections when the risk factors or severity signs for multi-resistant bacteria are apparent. The use of cephalosporins should be restricted to community-acquired infections.展开更多
Objective:To investigate the antimicrobial activity of Clitoria ternatea(C.ternatea) against the fish pathogens viz.,Pseudomonas aeruginosa(P.aeruginosa),Escherichia coli(E.coli),Klebsiella pneumonia(K.pneumonia),Baci...Objective:To investigate the antimicrobial activity of Clitoria ternatea(C.ternatea) against the fish pathogens viz.,Pseudomonas aeruginosa(P.aeruginosa),Escherichia coli(E.coli),Klebsiella pneumonia(K.pneumonia),Bacillus subtilis(B.subtilis),Aeromonas formican(A.formicans)s, Aeromonas hydrophila(A.hydrophila) and Streptococcus agalactiae(S.agalactiae )isolated from diseased Tilapia(Oreochromis niloticus).Methods:The extracts of C.ternatea was tested against P.aeruginosa,E.coli,K.pneumonia,B.subtilis,A.formicans,A.hydrophila and S.agalactiae by the agar well diffusion method.Results:Different extracts of C.ternatea showed inhibitory effects against P.aeruginosa,E.coli,K.pneumonia,B.subtilis,A.formicans,A.hydrophila and S. agalactiae.Ethyl acetate extracts of C.ternatea showed maximum of zone of inhibition against A. formicans(18 mm),A.hydrophilia(19 mm),B.subtilis(19 mm) and P.aeruginosa(21 mm) next to that ethanol extract of C.ternatea showed A.formicans(18 mm) and E.coli(14 mm) followed by Acetone extract showed maximum zone of inhibition S.agalactiae(19 mm) and K.pneumonia(17 mm).Conclusions:The antimicrobial activities of all the four plant extracts are comparable and their potential as alternative in the treatment of infectious by these microorganisms was present in the fish.Susceptibility testing is conducted on isolates using drugs selected on the basis of their importance to human medicine and use in fish production.展开更多
A tremendous amount of imported fresh fruits has been delivered to Shanghai markets, increasing the risk of invasion by harmful plant pathogens. Therefore, it is important to establish an effective detection and super...A tremendous amount of imported fresh fruits has been delivered to Shanghai markets, increasing the risk of invasion by harmful plant pathogens. Therefore, it is important to establish an effective detection and supervision system to survey the outbreak of the market diseases of the imported fruits during marketing. The samples were regularly surveyed in different markets to examine varieties, prices, localities, selling conditions, and diseases of the imported fruits from 2004 to 2008. The survey showed that 58 species of 30 different fruits were imported to Shanghai from 16 countries with more expensive price. The larger products were bananas, grapes, apples, and oranges. During the investigation, we found that the imported fruits frequently brought about the relatively serious market diseases. On the basis of morphology and the nuclear internal transcribed spacer （ITS） of ribosomal DNA （rDNA） analysis, 151 isolates of 15 fungi genera, which shown to be pathogenic after the inoculation assay, were finally identified. Among the identified fungi, Alternaria was the most frequent one with the highest detection rate （47.68%）, followed by Penicillium （14.57%） and Fusarium （11.92%）, respectively. Additionally, Pestalotiopsis microspora （detected in grapes Red-Globe coming from the USA） and Botrytis sp. （detected in black-plums coming from the USA） were first reported in China market. The present study summarized the selling situation of the imported fruits in Shanghai markets and constructed a library of the pathogens detected in the imported fruits during the selling period. The results obtained are useful to offer technical parameters for Chinese quarantine in order to prevent an invasion of the foreign harmful micro-organisms.展开更多
The Three Gorges Reservoir （TGR）, formed by China＇s Yangtze Three Gorges Project, is the largest lake in the world, but there is too little information available about fecal contamination and waterborne pathogen im...The Three Gorges Reservoir （TGR）, formed by China＇s Yangtze Three Gorges Project, is the largest lake in the world, but there is too little information available about fecal contamination and waterborne pathogen impacts on this aquatic ecosystem. During two successive 1-year study periods （July 2009 to July 2011）, the water quality in Wanzhou watershed of the TGR was tested with regard to the presence of fecal indicators and pathogens. According to Chinese and World Health Organization water quality standards, water quality in the mainstream was good but poor in backwater areas. Salmonella, Enterohemorrhagic Escherichia coli （EHEC）, Giardia and Cryptosporidium were detected in the watershed. Prevalence and concentrations of the pathogens in the mainstream were lower than those in backwater areas. The estimated risk of infection with Salmonella, EHEC, Cryptosporidium, and Giardia per exposure event ranged from 2.9 × 10 -7 to 1.68 × 10-5 , 7.04 × 10-10 to 2.36 × 10-7 , 5.39 × 10-6 to 1.25 × 10-4 and 0 to 1.2 × 10-3 , respectively, for occupational divers and recreational swimmers exposed to the waters. The estimated risk of infection at exposure to the 95% upper confidence limit concentrations of Salmonella, Cryptosporidium and Giardia may be up to 2.62 × 10-5 , 2.55 × 10-4 and 2.86 × 10-3 , respectively. This study provides useful information for the residents, health care workers and managers to improve the safety of surface water and reduce the risk of fecal contamination in the TGR.展开更多
Raw poultry and poultry products are a significant source of zoonotic bacterial pathogen transmission;thus the sensitive detection of major zoonotic pathogens (Salmonella spp., Campylobacter jejuni, and Listeria monoc...Raw poultry and poultry products are a significant source of zoonotic bacterial pathogen transmission;thus the sensitive detection of major zoonotic pathogens (Salmonella spp., Campylobacter jejuni, and Listeria monocytogenes) is a vital food safety issue. Recently, third generation PCR technology, known as droplet digital PCR (ddPCR) has been developed to be more accurate and sensitive to detect genetic targets than current quantification methods, but this technology has not been tested within an industrial setting. There is an on-going study within our laboratory is investigating the effects of sampling times and sampling methods on the cultural and molecular (via qPCR) quantification of dominant zoonotic pathogens within a poultry processing facility. This presents a unique opportunity to compare the quantification resulted from this emerging, third generation technology to traditional quantification methods currently employed by the poultry industry. The results show that ddPCR detected pathogen-specific genes from more pathogen:sampling time combinations than either the qPCR or culturing methods from the final scalder and chiller tanks at three stages of processing (Start, Mid, and End). In fact, both ddPCR and qPCR substantially outperformed culture methods commonly used in poultry processing food safety-related studies, with Salmonella recovered only from the Mid and End sampling times from the scalder tank. While neither C. jejuni nor L. monocytogenes were recovered culturally, ddPCR was able to detect their respective genes commonly throughout the processing day in both the scalder and chiller water samples. Additionally, the use of unfiltered processing water provided significantly greater detection of bacterial and pathogen-specific gene abundances than did an analysis of larger volumes of filtered water. Considering the ddPCR-derived concentrations of the bacterial pathogens were consistent with what was previously found culturally in commercial poultry processing operations, ddPCR represented a significant advancement in poultry processing zoonotic pathogen quantification.展开更多
Objective To develop a rapid and definite diagnostic test of bacterial enteritis caused by pathogenic enterobacteria, the most frequent etiologic agent of infectious enteritis in the world. Methods A set of convention...Objective To develop a rapid and definite diagnostic test of bacterial enteritis caused by pathogenic enterobacteria, the most frequent etiologic agent of infectious enteritis in the world. Methods A set of conventional PCR assays were applied to detect and identify salmonella, shigella, and E. coli O157:H7 directly from pure culture and fecal samples. The general primers of pathogenic enterobacteria were located on the uidA gene, which were found not only in E. coli nuclear acid, but also in Shigella and salmonella genes. Shigella primer was from ipaH gene whose coded invasive plasmid relative antigen existed both in plasmid and in genome. The primers of salmonella were designed from the 16SrRNA sequence. The primer of E.coli O157:H7 was taken from eaeA gene. Five random primers were selected for RAPD. The detection system included common PCR, semi-nested PCR and RAPD. Results This method was more sensitive, specific and efficient and its processing was rapid and simple. For example, the method could be used to specifically detect and identify salmonella, shigella, and E. coli O157:H7, and its sensitivity ranged from 3 to 50 CFU, and its detection time was 4 hours. Conclusion This PCR method, therefore, can serve as a routine and practical protocol for detecting and identifying pathogenic microorganisms from clinical samples.展开更多
In this study, qPCR was used to quantify opportunistic premise plumbing pathogens(OPPPs) and free-living amoebae in 11 tap water samples collected over four seasons from a city in northern China. Results demonstrated ...In this study, qPCR was used to quantify opportunistic premise plumbing pathogens(OPPPs) and free-living amoebae in 11 tap water samples collected over four seasons from a city in northern China. Results demonstrated that the average numbers of gene copies of Legionella spp. and Mycobacterium spp. were significantly higher than those of Aeromonas spp.(p < 0.05). Legionella spp. and Mycobacterium spp. were 100%(44/44) positively detected while P. aeruginosa and Aeromonas spp. were 79.54%(35/44) and 77.27%(34/44) positively detected. Legionella pneumophila was only detected in 4 samples(4/44), demonstrating its occasional occurrence. No Mycobacterium avium or Naegleria fowleri was detected in any of the samples. The average gene copy numbers of target OPPPs were the highest in summer,suggesting seasonal prevalence of OPPPs. Average gene copy numbers of OPPPs in the taps of low-use-frequency were higher than in taps of high-use-frequency, but the difference was not significant for some OPPPs(p > 0.05). Moderate negative correlations between the chlorine concentration and the gene copy numbers of OPPPs were observed by Spearman analysis(rsranged from -0.311 to -0.710, p < 0.05). However, no significant correlations existed between OPPPs and AOC, BDOC, or turbidity. Moderate positive correlations were observed between the target microorganisms, especially for Acanthamoeba spp., through Spearman analysis(p < 0.05). Based on our studies, it is proposed that disinfectant concentration, season, taps with different-use frequency, OPPP species, and potential microbial correlations should be considered for control of OPPPs in tap water.展开更多
基金supported by the Key Research and Development Program of Shandong Province,China(No 2021CXGC010803)Pan’an County Chinese Medicine Industry Project(No.PZYF202103).
文摘Reductive soil disinfestation(RSD)is commonly employed for soil remediation in greenhouse cultivation.However,its influence on antibiotic resistance genes(ARGs)in soil remains uncertain.This study investigated the dynamic changes in soil communities,potential bacterial pathogens,and ARG profiles under various organicmaterial treatments during RSD,including distillers’grains,potato peel,peanut vine,and peanut vine combined with charcoal.Results revealed that applying diverse organic materials in RSD significantly altered bacterial community composition and diminished the relative abundance of potential bacterial pathogens(P<0.05).The relative abundance of high-risk ARGs decreased by 10.7%-30.6%after RSD treatments,the main decreased ARG subtypeswere AAC(3)_Via,dfrA1,ErmB,lnuB,aadA.Actinobacteria was the primary host of ARGs and was suppressed by RSD.Soil physicochemical properties,such as total nitrogen,soil pH,total carbon,were crucial factors affecting ARG profiles.Our findings demonstrated that RSD treatment inhibited pathogenic bacteria and could be an option for reducing high-risk ARG proliferation in soil.
基金supported by the National Modern Agricultural Industry Technology System(CARS-45-33)Innovation Team of Tianjin Freshwater Aquaculture Industry Technology System(ITTFRS2021000-002,ITTFRS2021000-001)+1 种基金Tianjin Science and Technology Plan Project(24KPHDRC00280,24ZYCGSN00250,23YDTPJC00420)the Open Fund Project of Key Laboratory of Ocean Observation Technology,MNR(No.2023klootA03).
文摘The sustainable development of aquaculture industry is deeply constrained by pathogens and diseases,and traditional detection methods are difficult to adapt to the needs of intensive aquaculture due to low efficiency and insufficient sensitivity.This article reviews the progress of rapid detection technology for aquatic pathogens based on molecular biology,immunology,biosensors,etc.,and analyzes the application value of innovative methods such as isothermal amplification and CRISPR.This technology injects core momentum into the new quality productivity of fisheries through early and precise identification of pathogens:reducing aquaculture losses to improve resource efficiency,promoting the transformation of aquaculture models to data-driven,ensuring the safety of aquatic products to enhance the competitiveness of the industry chain.The current technology has shortcomings such as lagging standardization,weak on-site anti-interference ability,and insufficient recognition of new pathogens.In the future,we need to focus on technological integration and innovation,intelligent upgrading,and standardization construction,promote technology from laboratories to industrial applications,and provide continuous support for the high-quality development of fisheries.
基金supported by the National Natural Science Foundation of China(32060520)Science and Technology Talents and Platform Program of Yunnan Province(202105AF150049)University Key Laboratory of Food Microbial Resources and Utilization in Yunnan Province(Yunjiaofa[2018]No.135).
文摘In order to ensure food safety,controlling foodborne pathogen contamination is of utmost importance.Growing apprehensions regarding the safety of synthetic antimicrobials,due to their adverse health effects,have prompted a search for alternative options.Plant natural products(PNPs)with antimicrobial activity are being explored as a viable alternative.Among the various antimicrobial natural products studied,plant essential oils,plant flavonoids,plant polyphenols,plant polysaccharides,and plant antimicrobial peptides have been identified as potential candidates.PNPs demonstrate a diverse array of antimicrobial mechanisms,encompassing cell wall and membrane damage,interference with genetic replication,disruption of energy metabolism,and induction of oxidative stress at the single-cell level,as well as inhibition of biofilm formation and quorum sensing at the population level.Certain PNPs have been harnessed as natural antimicrobial agents for the food preservation.The utilization of encapsulation technology proves to be an effective strategy in protecting PNPs,thereby ensuring good antimicrobial efficacy,enhanced dispersibility,and controlled release within food products.The utilization of nanoemulsions,nanoliposomes,edible packaging,electrospun nanofibers,and microcapsules formed by encapsulation has enriched the ways in which PNPs can be applied in food preservation.Although PNPs have great potential in food preservation,their widespread application in the food industry is currently constrained by factors such as production costs,safety concerns,and legal considerations.Chemical synthesis and biosynthesis pathways offer viable strategies for reducing the cost of producing PNPs,and ongoing efforts to assess safety and improve regulatory frameworks are likely to facilitate the broader adoption of PNPs in food preservation practices.This article provides an overview of the main types of PNPs with antimicrobial activity and their properties,focusing on their mechanisms of action.Additionally,it summarizes the use of PNPs in food preservation and discusses the characteristics and applications of different encapsulation technologies.Lastly,the paper briefly analyzes current limitations and proposes potential future trends for this field.
基金supported by the Beijing Science and Technology Planning Project of the Beijing Science and Technology Commission(Z241100009024047)the High-Level Public Health Technical Talent Training Plan(lingjunrencai-01-02).
文摘Respiratory infections are associated with high morbidity and mortality and are a major global health problem[1].Acute respiratory infections are caused by multiple respiratory pathogens,including viruses and bacteria.Viral-bacterial co-infections,which have become increasingly common and a global concern,can lead to substantial complications,causing higher morbidity and adverse prognosis[2].Previous studies have reported low positive detection rates of targeted pathogens related to acute respiratory infections,owing to the limited number of detected pathogens and variations in the sensitivity of diagnostic methods[3-4].Low positive detection rates may impede our understanding of respiratory pathogen characteristics and hamper the development of precise treatment and prevention strategies.
基金Major National Science and Technology Projects(Grant No.2013ZX10004605,2013ZX10004605001004)
文摘The pathogens and opinion for antibiotic treatment in adult patients with 1-14 fecal white blood cells per high power field （WBC/HPF） of acute non-bloody diarrhea remain obscure. The study attempts to clarify it. Stool specimens of adult patients with acute non-bloody diarrhea and stool examination showing 1-14 fecal WBC/HPF were collected for bacterial culture and viral detection. Patients included in this study were 196 cases with mean age of （37.9±17.4） years and 42.3% was women. The bacterial and viral detection rates were 63 （32.1%） and 21 （10.7%）, respectively. Of the isolated pathogens, campylobacteria was present in 14 （22.0%） samples and was the most common bacteria and calicivirus was found in 10 （47.6%） samples and was the most common virus. Based on single pathogens, 46 cases were caused by invasive pathogens, 26 cases were caused by non-invasive pathogens. The body temperature was significantly higher in feverish patients caused by invasive pathogens than those caused by non-invasive pathogens （（38.44-0.7） ℃ vs （37.74-0.4） ℃, P = 0.002）. The probability of diarrhea caused by invasive pathogens was higher in patients with T〉38.4℃ than those with T_〈38.4℃ （RR = 1.5）. When T〉38.4℃ is used as the threshold for antibiotic treatment, the misuse rate of antibiotics would decrease from 26.9% to 3.8% （P = 0.021）. So T〉38.4 ℃ may be used as a possible reference value for antibiotic treatment in adult patients with 1-14 fecal WBC/HPF of acute non-bloody diarrhea.
基金Supported by Science and Technology Plan Project of Fujian Province(2013Y0063)Xiamen South Ocean Research Centre Project(13GZP002NF08)~~
文摘[Objective] The aim of this study was to purify an antimicrobial protein from a biocontrol bacterium strain K2-1 and analyze its antimicrobial activity in vitro against some typical aquatic pathogens. [Method] The antimicrobial protein was ob- tained by using ammonium sulfate precipitation and Sephadex chromatography combined with hot water bath. The antimicrobial assay was conducted by means of agar diffusion technique, using Vibrio alginolyticus, Aeromonas hydrophila, Aeromonas. Sobria, Pseudomonas fluorescens, Vibrio Parahaemolyticus, Vibrio har- veyi and Vibrio anguillarum as test bacteria. [Result] Antimicrobial protein APK2 can be derived from fermentation broth of strain K2-1 and purified to the chromatogra- phy pure level by the methods provided, the final yield of the antimicrobial compo- nent is approximately 0.08%. This antimicrobial protein had a strong antimicrobial activity against the growth of most those bacteria. [Conclusion] The results show that APK2 could be a potential alternative to replace chemical antimicrobial agent in the control and prevention of aquatic diseases.
基金supported by the National Natural Science Foundation of China(No.51290281)the project of Chinese Academy of Sciences(No.QYZDY-SSW-DQC004)the Federal Department of Chinese Water Control and Treatment(Nos.2017ZX07108,2017ZX07501002)
文摘The effects of O3/Cl2 disinfection on corrosion and the growth of opportunistic pathogens in drinking water distribution systems were studied using annular reactors （ARs）. The corrosion process and most probable number （MPN） analysis indicated that the higher content of iron-oxidizing bacteria and iron-reducing bacteria in biofilms of the AR treated with O3/Cl2 induced higher Fe304 formation in corrosion scales. These corrosion scales became more stable than the ones that formed in the AR treated with Cl2 alone. O3/Cl2 disinfection inhibited corrosion and iron release efficiently by changing the content of corrosion-related bacteria. Moreover, ozone disinfection inactivated or damaged the opportunistic pathogens due to its strong oxidizing properties. The damaged bacteria resulting from initial ozone treatment were inactivated by the subsequent chlorine disinfection. Compared with the AR treated with Cl2 alone, the opportunistic pathogens M. auium and L. pneumophila were not detectable in effluents of the AR treated with O3/Cl2, and decreased to （4.60 ± 0.14） and （3.09 ± 0.12） loglo （gene copies/g corrosion scales） in biofilms, respectively. The amoeba counts were also lower in the AR treated with O3/Cl2. Therefore, O3/Cl2 disinfection can effectively control opportunistic pathogens in effluents and biofilms of an AR used as a model for a drinking water distribution system.
基金supported in part by the Universidad de los Andes Faculty of Sciencesby basic sciences project P13.700022.007 from the University of los Andes Office of Research+1 种基金by COLCIENCIAS grant # 120-4521-28532Colciencias (Programa de Apoyo a Doctorados Nacionales) for the financial support of the Ph.D. studies of M.F.G. and H.Y.N.-O
文摘The importance of pyrimidines lies in the fact that they are structural components of a broad spectrum of key molecules that participate in diverse cellular functions, such as synthesis of DNA, RNA, lipids, and carbohydrates. Pyrimidine metabolism encompasses all enzymes involved in the synthesis, degradation, salvage, interconversion and transport of these molecules. In this review, we summarize recent publications that document how pyrimidine metabolism changes under a variety of conditions, including, when possible, those studies based on techniques of genomics, transcriptomics, proteomics, and metabolomics. First, we briefly look at the dynamics of pyrimidine metabolism during nonpathogenic cellular events. We then focus on changes that pathogen infections cause in the pyrimidine metabolism of their host. Next, we discuss the effects of antimetabolites and inhibitors, and finally we consider the consequences of genetic ma- nipulations, such as knock-downs, knock-outs, and knock-ins, of pyrimidine enzymes on pyrimidine metabolism in the cell.
基金supported by the National Natural Science Foundation of China(No.51138006)the National Key Research on Water Environment Pollution Control in China(No.2012ZX07301-001)
文摘The emergence and prevalence of antibiotic resistance genes(ARGs) and pathogens in the environment are serious global health concern. However, information about the occurrence of ARGs and pathogens in recreational water is still limited. Accordingly, we investigated the occurrence of six ARGs and human pathogens in three recreational lakes, and the correlations between ARGs and one mobile genetic element(intI1) were analyzed. The quantitative PCR results showed that the concentration of ARGs ranged from 4.58 × 10~0 to 5.0 × 10~5 copies/mL in water and from 5.78 × 10~3 to 5.89 × 10~8 copies/g dry weight(dw)in sediment. Sul1 exhibited the highest level among the five quantifiable ARGs. The concentrations of sul1, bla_(-TEM), and tetX exhibited significant positive correlations with intI1(p < 0.05), indicating that intI1 may be involved in their proliferation. The detection frequencies of ARGs ranged from 75%–10~0%, indicating the prevalence of these risks in this region. The concentration of Escherichia coli, Aeromonas spp., Mycobacterium avium,Pseudomonas aeruginosa, and Salmonella enterica ranged from 10~3 to 10~5 copies/10~0 mL in water and 10~4–10~6 copies/g dw in sediment. In total, 25% of the samples harbored all pathogen genes, indicating the prevalence of these pathogens in recreational lakes.Furthermore, the next-generation sequencing results showed that 68 genera of pathogens were present, among which Aeromonas, Mycobacterium, and Pseudomonas were the dominant ones in this region, posing a considerable potential health risk to public health. Overall, the widespread distribution of ARGs and pathogens underscores the need to better monitor and mitigate their propagation in recreational lakes and the associated risks to human health.
基金supported by the National Basic Research Development Program of China(Grant No. 2009CB118401)the National High-tech Research and Development Program of China(Grant Nos.2012AA10A305 and 2012AA 101104)
文摘Plant pathogens have evolved numerous strategies to obtain nutritive materials from their host, and plants in turn have evolved the preformed physical and chemical barriers as well as sophisticated two-tiered immune system to combat pathogen attacks. Genetically, plant resistance to pathogens can be divided into qualitative and quantitative disease resistance, conditioned by major gene（s） and multiple genes with minor effects, respectively. Qualitative disease resistance has been mostly detected in plant defense against biotrophic pathogens, whereas quantitative disease resistance is involved in defense response to all plant pathogens, from biotrophs, hemibiotrophs to necrotrophs. Plant resistance is achieved through interception of pathogen-derived effectors and elicitation of defense response. In recent years, great progress has been made related to the molecular basis underlying host--pathogen interactions. In this review, we would like to provide an update on genetic and molecular aspects of plant resistance to pathogens.
基金the California Department of Food and Agriculture Fruit Tree, Nut Tree, and Grapevine Improvement Advisory Board, USA
文摘Due to increasing regulations and restrictions, there is an urgent need to develop effective alternatives to chemical-dependent fumigation control of soilborne pests and pathogens. Anaerobic soil disinfestation （ASD） is one such alternative showing great promise for use in the control of soilborne pathogens and pests. This method involves the application of a carbon source, irrigation to field capacity, and covering the soil with a plastic tarp. While the mechanisms of ASD are not completely understood, they appear to be a combination of changes in the soil microbial community composition, production of volatile organic compounds, and the generation of lethal anaerobic conditions. The variety of materials and options for ASD application, including carbon sources, soil temperature, and plastic tarp type, influence the efficacy of pathogen sup- pression and disease control. Currently, both dry （e.g., rice bran） and liquid （e.g., ethanol） carbon sources are commonly used, but with different results depending on environmental conditions. While solarization is not an essential component of ASD, it can enhance efficacy. Understanding the mechanisms that mediate biological changes occurring in the soil during ASD will facilitate our ability to increase ASD efficacy while enhancing its commercial viability.
基金supported by grants from the Priority Project on Infectious Disease Control and Prevention(2012ZX10004215,2013ZX10004610)from Ministry of Health,China,and the Science Foundation for the State Key Laboratory for Infectious Disease Prevention and Control from China(Grant No.2015SKLID508)the National Natural Science Foundation of China(Grant No.81671985)and(Grant No.81170009)
文摘Objective Lower respiratory tract infections continue to pose a significant threat to human health. It is important to accurately and rapidly detect respiratory bacteria. To compensate for the limits of current respiratory bacteria detection methods, we developed a combination of multiplex polymerase chain reaction （PCR） and capillary electrophoresis （MPCE） assay to detect thirteen bacterial pathogens responsible for lower respiratory tract infections, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catorrholis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Mycoplasma pneumoniae, Legionella spp., Bordetella pertussis, Mycobacterium tuberculosis complex, Corynebactefium diphthefiae, and Streptococcus pyogenes. Methods Three multiplex PCR reactions were built, and the products were analyzed by capillary electrophoresis using the high-throughput DNA analyzer. The specificity of the MPCE assay was examined and the detection limit was evaluated using DNA samples from each bacterial strain and the simulative samples of each strain. This assay was further evaluated using 152 clinical specimens and compared with real-time PCR reactions. For this assay, three nested-multiplex-PCRs were used to detect these clinical specimens. Results The detection limits of the MPCE assay for the 13 pathogens were very low and ranged from 10-7 to 10-2 ng/μL. Furthermore, analysis of the 252 clinical specimens yielded a specificity ranging from 96.5%-100.0%, and a sensitivity of 100.0% for the 13 pathogens. Conclusion This study revealed that the MPCE with high specificity and sensitivity. This assay survey of respiratory pathogens. assay is a rapid, reliable, and high-throughput method has great potential in the molecular epidemiological.
基金project was approved by the research committee of Faculty of Medical Laboratory Sciences,University of Khartoum as Ph D degree requirements to Aymen Nurain
文摘Objective:To determine the prevalence and antimicrobial resistance rates of nosocomial pathogens isolated from cancer patients and hospital environments.Methods:A descriptive cross-sectional study was conducted between December 2010 to May 2013 at Radiation and Isotopes Centre of Khartoum,Sudan.A total of 1 503 samples(505 clinical and 998 environmental)were examined.Isolates were identified,and their antimicrobial susceptibility was determined using standard laboratory procedures.Results:Out of 505 clinical samples,nosocomial pathogens were found as 48.1%.Among hospital environment samples,bacterial contaminants were detected in 29.7%of samples.The main microorganisms recovered from cancer patients were Proteus spp.(23.5%),Escherichia coli(22.2%),Pseudomonas aeruginosa(P.aeruginosa)(21.0%)and Staphylococcus aureus(20.2%).The most frequent isolates from hospital environments were Bacillus spp.(50.0%),Staphylococcus aureus(14.2%)and P.aeruginosa(11.5%).The proportions of resistance among Gram-negative pathogens from cancer patients were high for ampicillin,cefotaxime,ceftazidime and ceftriaxone.Moderate resistance rates were recorded to ciprofloxacin,such as 51.0%for P.aeruginosa,21.7%for Klebsiella pneumoniae and 55.5%for Escherichia coli.Except Klebsiella,there were no significant differences(P0.05)of resistance rates between Gram-negative isolates from cancer patients to those from the hospital environments.The proportions of extended-spectrum b-lactamase producing isolates from cancer patients were not differ significantly(P=0.763)from those collected from the hospital environments(49.2%;91/185 vs.47%;32/68).Conclusions:The prevalence of nosocomial infection among cancer patients was high(48.1%)with the increasing of antimicrobial resistance rates.Hospital environments are potential reservoirs for nosocomial infections,which calls for intervention program to reduce environmental transmission of pathogens.
文摘Spontaneous bacterial peritonitis(SBP) is the most typical infection observed in cirrhosis patients. SBP is responsible for an in-hospital mortality rate of approximately 32%. Recently, pattern changes in the bacterial flora of cirrhosis patients have been observed, and an increase in the prevalence of infections caused by multi-resistant bacteria has been noted. The wide-scale use of quinolones in the prophylaxis of SBP has promoted flora modifications and resulted in the development of bacterial resistance. The efficacy of traditionally recommended therapy has been low in nosocomial infections(up to 40%), and multi-resistance has been observed in up to 22% of isolated germs in nosocomial SBP. For this reason, the use of a broad empirical spectrum antibiotic has been suggested in these situations. The distinction between community-acquired infectious episodes, healthcare-associated infections, or nosocomial infections, and the identification of risk factors for multi-resistant germs can aid in the decision-making process regarding the empirical choice of antibiotic therapy. Broad-spectrum antimicrobial agents, such as carbapenems with or without glycopeptides or piperacillin-tazobactam, should be considered for the initial treatment not only of nosocomial infections but also of healthcare-associated infections when the risk factors or severity signs for multi-resistant bacteria are apparent. The use of cephalosporins should be restricted to community-acquired infections.
文摘Objective:To investigate the antimicrobial activity of Clitoria ternatea(C.ternatea) against the fish pathogens viz.,Pseudomonas aeruginosa(P.aeruginosa),Escherichia coli(E.coli),Klebsiella pneumonia(K.pneumonia),Bacillus subtilis(B.subtilis),Aeromonas formican(A.formicans)s, Aeromonas hydrophila(A.hydrophila) and Streptococcus agalactiae(S.agalactiae )isolated from diseased Tilapia(Oreochromis niloticus).Methods:The extracts of C.ternatea was tested against P.aeruginosa,E.coli,K.pneumonia,B.subtilis,A.formicans,A.hydrophila and S.agalactiae by the agar well diffusion method.Results:Different extracts of C.ternatea showed inhibitory effects against P.aeruginosa,E.coli,K.pneumonia,B.subtilis,A.formicans,A.hydrophila and S. agalactiae.Ethyl acetate extracts of C.ternatea showed maximum of zone of inhibition against A. formicans(18 mm),A.hydrophilia(19 mm),B.subtilis(19 mm) and P.aeruginosa(21 mm) next to that ethanol extract of C.ternatea showed A.formicans(18 mm) and E.coli(14 mm) followed by Acetone extract showed maximum zone of inhibition S.agalactiae(19 mm) and K.pneumonia(17 mm).Conclusions:The antimicrobial activities of all the four plant extracts are comparable and their potential as alternative in the treatment of infectious by these microorganisms was present in the fish.Susceptibility testing is conducted on isolates using drugs selected on the basis of their importance to human medicine and use in fish production.
基金supported by the National Natural Sci-ence Foundation of China (30771505)the projects of Shanghai Science and Technology Commission,China (07DZ12043)
文摘A tremendous amount of imported fresh fruits has been delivered to Shanghai markets, increasing the risk of invasion by harmful plant pathogens. Therefore, it is important to establish an effective detection and supervision system to survey the outbreak of the market diseases of the imported fruits during marketing. The samples were regularly surveyed in different markets to examine varieties, prices, localities, selling conditions, and diseases of the imported fruits from 2004 to 2008. The survey showed that 58 species of 30 different fruits were imported to Shanghai from 16 countries with more expensive price. The larger products were bananas, grapes, apples, and oranges. During the investigation, we found that the imported fruits frequently brought about the relatively serious market diseases. On the basis of morphology and the nuclear internal transcribed spacer （ITS） of ribosomal DNA （rDNA） analysis, 151 isolates of 15 fungi genera, which shown to be pathogenic after the inoculation assay, were finally identified. Among the identified fungi, Alternaria was the most frequent one with the highest detection rate （47.68%）, followed by Penicillium （14.57%） and Fusarium （11.92%）, respectively. Additionally, Pestalotiopsis microspora （detected in grapes Red-Globe coming from the USA） and Botrytis sp. （detected in black-plums coming from the USA） were first reported in China market. The present study summarized the selling situation of the imported fruits in Shanghai markets and constructed a library of the pathogens detected in the imported fruits during the selling period. The results obtained are useful to offer technical parameters for Chinese quarantine in order to prevent an invasion of the foreign harmful micro-organisms.
基金supported by the Key Project of Chinese Ministry of Education (No. 211150)the Natural Science Foundation Project of CQ CSTC (No. cstc 2013 JCY-JA20011)+1 种基金the China Postdoctoral Science Foundation (No. 20110491855)the Science and Technology Projects of Chongqing Municipal Education Commission, China (No. KJ111115)
文摘The Three Gorges Reservoir （TGR）, formed by China＇s Yangtze Three Gorges Project, is the largest lake in the world, but there is too little information available about fecal contamination and waterborne pathogen impacts on this aquatic ecosystem. During two successive 1-year study periods （July 2009 to July 2011）, the water quality in Wanzhou watershed of the TGR was tested with regard to the presence of fecal indicators and pathogens. According to Chinese and World Health Organization water quality standards, water quality in the mainstream was good but poor in backwater areas. Salmonella, Enterohemorrhagic Escherichia coli （EHEC）, Giardia and Cryptosporidium were detected in the watershed. Prevalence and concentrations of the pathogens in the mainstream were lower than those in backwater areas. The estimated risk of infection with Salmonella, EHEC, Cryptosporidium, and Giardia per exposure event ranged from 2.9 × 10 -7 to 1.68 × 10-5 , 7.04 × 10-10 to 2.36 × 10-7 , 5.39 × 10-6 to 1.25 × 10-4 and 0 to 1.2 × 10-3 , respectively, for occupational divers and recreational swimmers exposed to the waters. The estimated risk of infection at exposure to the 95% upper confidence limit concentrations of Salmonella, Cryptosporidium and Giardia may be up to 2.62 × 10-5 , 2.55 × 10-4 and 2.86 × 10-3 , respectively. This study provides useful information for the residents, health care workers and managers to improve the safety of surface water and reduce the risk of fecal contamination in the TGR.
文摘Raw poultry and poultry products are a significant source of zoonotic bacterial pathogen transmission;thus the sensitive detection of major zoonotic pathogens (Salmonella spp., Campylobacter jejuni, and Listeria monocytogenes) is a vital food safety issue. Recently, third generation PCR technology, known as droplet digital PCR (ddPCR) has been developed to be more accurate and sensitive to detect genetic targets than current quantification methods, but this technology has not been tested within an industrial setting. There is an on-going study within our laboratory is investigating the effects of sampling times and sampling methods on the cultural and molecular (via qPCR) quantification of dominant zoonotic pathogens within a poultry processing facility. This presents a unique opportunity to compare the quantification resulted from this emerging, third generation technology to traditional quantification methods currently employed by the poultry industry. The results show that ddPCR detected pathogen-specific genes from more pathogen:sampling time combinations than either the qPCR or culturing methods from the final scalder and chiller tanks at three stages of processing (Start, Mid, and End). In fact, both ddPCR and qPCR substantially outperformed culture methods commonly used in poultry processing food safety-related studies, with Salmonella recovered only from the Mid and End sampling times from the scalder tank. While neither C. jejuni nor L. monocytogenes were recovered culturally, ddPCR was able to detect their respective genes commonly throughout the processing day in both the scalder and chiller water samples. Additionally, the use of unfiltered processing water provided significantly greater detection of bacterial and pathogen-specific gene abundances than did an analysis of larger volumes of filtered water. Considering the ddPCR-derived concentrations of the bacterial pathogens were consistent with what was previously found culturally in commercial poultry processing operations, ddPCR represented a significant advancement in poultry processing zoonotic pathogen quantification.
文摘Objective To develop a rapid and definite diagnostic test of bacterial enteritis caused by pathogenic enterobacteria, the most frequent etiologic agent of infectious enteritis in the world. Methods A set of conventional PCR assays were applied to detect and identify salmonella, shigella, and E. coli O157:H7 directly from pure culture and fecal samples. The general primers of pathogenic enterobacteria were located on the uidA gene, which were found not only in E. coli nuclear acid, but also in Shigella and salmonella genes. Shigella primer was from ipaH gene whose coded invasive plasmid relative antigen existed both in plasmid and in genome. The primers of salmonella were designed from the 16SrRNA sequence. The primer of E.coli O157:H7 was taken from eaeA gene. Five random primers were selected for RAPD. The detection system included common PCR, semi-nested PCR and RAPD. Results This method was more sensitive, specific and efficient and its processing was rapid and simple. For example, the method could be used to specifically detect and identify salmonella, shigella, and E. coli O157:H7, and its sensitivity ranged from 3 to 50 CFU, and its detection time was 4 hours. Conclusion This PCR method, therefore, can serve as a routine and practical protocol for detecting and identifying pathogenic microorganisms from clinical samples.
基金supported by the National Key Research and Development Plan(No.2016YFA0203200)the National Natural Science Foundation of China(No.51538013)the project of Chinese Academy of Sciences(No.QYZDY-SSW-DQC004)
文摘In this study, qPCR was used to quantify opportunistic premise plumbing pathogens(OPPPs) and free-living amoebae in 11 tap water samples collected over four seasons from a city in northern China. Results demonstrated that the average numbers of gene copies of Legionella spp. and Mycobacterium spp. were significantly higher than those of Aeromonas spp.(p < 0.05). Legionella spp. and Mycobacterium spp. were 100%(44/44) positively detected while P. aeruginosa and Aeromonas spp. were 79.54%(35/44) and 77.27%(34/44) positively detected. Legionella pneumophila was only detected in 4 samples(4/44), demonstrating its occasional occurrence. No Mycobacterium avium or Naegleria fowleri was detected in any of the samples. The average gene copy numbers of target OPPPs were the highest in summer,suggesting seasonal prevalence of OPPPs. Average gene copy numbers of OPPPs in the taps of low-use-frequency were higher than in taps of high-use-frequency, but the difference was not significant for some OPPPs(p > 0.05). Moderate negative correlations between the chlorine concentration and the gene copy numbers of OPPPs were observed by Spearman analysis(rsranged from -0.311 to -0.710, p < 0.05). However, no significant correlations existed between OPPPs and AOC, BDOC, or turbidity. Moderate positive correlations were observed between the target microorganisms, especially for Acanthamoeba spp., through Spearman analysis(p < 0.05). Based on our studies, it is proposed that disinfectant concentration, season, taps with different-use frequency, OPPP species, and potential microbial correlations should be considered for control of OPPPs in tap water.
