重组体pET-28a-alkB/E.coli降解页岩油泥石油烃的功能研究

为了降解页岩油泥中的石油烃,构建基因工程菌,表达石油烃降解关键酶以提高油泥的降解效果。以Pseudomonas qingdaonensis基因组为模板扩增alkB基因,连接至载体pET-28a,转化至E.coli BL21(DE3)中,SDS-PAGE和Western-blot鉴定表达的外源蛋白。pET-28a-alkB/E.coli处理原油和页岩油泥,采用气相色谱法评估降解效果。发现alkB基因在大肠杆菌中能表达外源蛋白,且14 d原油及页岩油泥的降解率分别为47.5%和47.1%,表明重组体pET-28a-alkB/E.coli具备降解页岩油泥石油烃的功能。

Exploring the modulatory role of bovine lactoferrin on the microbiome and the immune response in healthy and Shiga toxin‑producing E.coli challenged weaned piglets

Background Post-weaned piglets suffer from F18+Escherichia coli(E.coli)infections resulting in post-weaning diar-rhoea or oedema disease.Frequently used management strategies,including colistin and zinc oxide,have contrib-uted to the emergence and spread of antimicrobial resistance.Novel antimicrobials capable of directly interacting with pathogens and modulating the host immune responses are being investigated.Lactoferrin has shown promising results against porcine enterotoxigenic E.coli strains,both in vitro and in vivo.Results We investigated the influence of bovine lactoferrin(bLF)on the microbiome of healthy and infected weaned piglets.Additionally,we assessed whether bLF influenced the immune responses upon Shiga toxin-producing E.coli(STEC)infection.Therefore,2 in vivo trials were conducted:a microbiome trial and a challenge infection trial,using an F18+STEC strain.BLF did not affect theα-andβ-diversity.However,bLF groups showed a higher relative abundance(RA)for the Actinobacteria phylum and the Bifidobacterium genus in the ileal mucosa.When analysing the immune response upon infection,the STEC group exhibited a significant increase in F18-specific IgG serum levels,whereas this response was absent in the bLF group.Conclusion Taken together,the oral administration of bLF did not have a notable impact on theα-andβ-diversity of the gut microbiome in weaned piglets.Nevertheless,it did increase the RA of the Actinobacteria phylum and Bifi-dobacterium genus,which have previously been shown to play an important role in maintaining gut homeostasis.Furthermore,bLF administration during STEC infection resulted in the absence of F18-specific serum IgG responses.

Impact of an oligosaccharide-based polymer on the metabolic profiles and microbial ecology of weanling pigs experimentally infected with a pathogenic E.coli

Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to carbadox.The objective of this study was to investigate the impacts of oligosaccharide-based polymer or antibiotic on the host metabolic profiles and colon microbiota of weaned pigs experimentally infected with ETEC F18.Results Multivariate analysis highlighted the differences in the metabolic profiles of serum and colon digesta which were predominantly found between pigs supplemented with oligosaccharide-based polymer and antibiotic.The relative abundance of metabolic markers of immune responses and nutrient metabolisms,such as amino acids and carbohydrates,were significantly differentiated between the oligosaccharide-based polymer and antibiotic groups(q<0.2 and fold change>2.0).In addition,pigs in antibiotic had a reduced(P<0.05)relative abundance of Lachnospiraceae and Lactobacillaceae,whereas had greater(P<0.05)Clostridiaceae and Streptococcaceae in the colon digesta on d 11 post-inoculation(PI)compared with d 5 PI.Conclusions The impact of oligosaccharide-based polymer on the metabolic and microbial profiles of pigs is not fully understood,and further exploration is needed.However,current research suggest that various mechanisms are involved in the enhanced disease resistance and performance in ETEC-challenged pigs by supplementing this polymer.

Characteristics of β-Lactamase Synthesis in E. coli and K. pneumanie Strains in Nosocomial Infections

Background: Recently micro-organisms that synthesize extended-spectrum β-lactamase (ESBLs) were increased. The peculiarities of ESBL synthesis of Escherichia coli and Klebsiella pneumoniae strains that cause nosocomial urinary tract infections, surgical site infections and pneumonia in surgical clinic were studied. ESBL synthesis were observed 38.9% of E. coli strains obtained from urine, 92.3% of strains obtained from surgical site infections, and 50% of strains obtained from sputum. ESBL synthesis were observed 37.5% of K. pneumoniae strains obtained from urine, 85.7% of strains obtained from surgical site infections, and 60% of strains obtained from sputum. Different levels of ESBL synthesize of E. coli and K. pneumoniae strains isolated from different pattern is discussed. Conclusion. ESBL synthesis is common in E. coli and K. pneumoniae strains, which cause nosocomial infections. The frequency of occurrence of ESBL s synthesis among of these strains depends on clinical forms of nosocomial infections.

The Transport and Persistence of Escherichia coli in Leachate from Poultry Litter Amended Soils

Fecal coliform bacteria such as Escherichia coli (E. coli) are one of the main sources of groundwater pollution. An assessment of the transport and Persistence of E. coli in poultry litter amended Decatur silty Clay soil and Hartsells Sandy soil was conducted using soil columns and simulated groundwater leaching. Enumeration of initial E. coli was determined to range from 2.851 × 103 to 3.044 × 103 CFU per gram of soil. These results have been used in a batch study to determine the persistence rate of E. coli in Decatur silty Clay soil and Hartsells Sandy soil. Results prove that E. coli survival growth rate increases for clay soil later than and at a higher rate than sandy soil. The column study has determined that E. coli was transported at a rate of 3.7 × 106 CFU for Decatur silty loam and 6.3 × 106 CFU for Hartsells sandy per gram of soil. Further, linear regression analysis predictions show higher porosity and soil moisture content affect transport, and Hartsells sandy soil has higher transport of E. coli due to its higher porosity and lower volumetric water content.

Growth Inhibition of Escherichia coli and Staphylococcus epidermidis from Various Types of Honey

Honey has long been considered a wound treatment used to keep cuts and other epidermal injuries clean. This study tested that claim by comparing manuka honey used in medicine today, local unprocessed honey taken straight from a hive, and pasteurized honey found at a store, on strains of E. coli and S. epidermidis. The study evaluated the effects these honeys had on bacterial growth to determine which had the greatest inhibition of bacterial growth. To determine this, plates streaked with strains of E. coli or S. epidermidis bacteria and agar wells filled with one of the honeys were incubated and subsequently the diameter of the zone of inhibition was measured. After 20 trials using each honey and bacteria type, manuka and unprocessed were shown to have a statistically significant advantage over the pasteurized honey at inhibiting the growth of E. coli and S. epidermidis, though it was variable whether manuka had an advantage over the unprocessed honey.

Evaluating the Potential of Nitrofurantoin and Fosfomycin for E.coli UTIs: A Susceptibility Study

This study was designed to find the susceptibility of Nitrofurantoin and Fosfomycin among urinary isolates of Escherichia.coli.Four hundred(400)urine samples were collected for susceptibility of nitrofurantoin and fosfomycin among urinary isolates of E.coli.All indoor and outdoor patients'urinary samples yielded growth of E.coli.Mid-stream urine specimens were inoculated on blood agar and CLED agar and incubated at 35±2°C.Growth was observed,and Escherichia coli was identified by Gram staining,Catalase,Motility test and API 20E(Bio murex)as per standard procedure.Antimicrobial susceptibility testing of isolates for nitrofurantoin and fosfomycin was carried out by the modified Kirby-Bauer disc diffusion method according to CLSI guidelines ATCC 25922.E.coli was used as a quality control strain.A total of 400 samples were tested susceptibility of nitrofurantoin and fosfomycin among urinary isolates of E.coli during this period.A total of 400 samples yielded the growth of E.coli,out of which 178(44.5%)were male and 222(55.5%)were female samples.Among males,18(10%)were tolerant to nitrofurantoin,and 2(1.1%)were tolerant to fosfomycin.Among females,9(4.09%)were susceptible to nitrofurantoin while 6(2.72%)were susceptible to fosfomycin.Among age groups below 45 years old,6(4.76%)were tolerant to nitrofurantoin,and 2(1.58%)were sensitive to fosfomycin.Between 46-66 years old,4(2.81%)were sensitive to nitrofurantoin,and 3(2.11%)were sensitive to fosfomycin.Between 67-90 years old,17(12.87%)were sensitive to nitrofurantoin,and 4(3.03%)were tolerant to fosfomycin.Fosfomycin and nitrofurantoin showed good susceptibility in urinary isolates of E.coli and can be used empirically in our setup.

Detection of aac(3)IIc, aac(6)Ib, armA Genes Coding for Escherichia coli Resistance to Aminoglycosides in Burkina Faso

Background and Prupose: Antibiotic resistance is a major global health concern. In addition to the existing data on the prevalence of bacterial resistance to antibiotics, there are patchy data on bacterial resistance to aminoglycosides in Burkina Faso. In this study, we determined the prevalence of aminoglycoside resistance genes in E. coli, including aac(3)-IIc, aac(6)-Ib and armA in Ouagadougou, and determined which antibiotics in this class are most affected by resistance. Material and Methods: This study was conducted on 216 E. coli strains collected from the biomedical analysis laboratories of Saint Camille and Schiphra hospitals. E. coli strains were isolated from pus and urine samples collected between September 2018 and January 2019. Antibiotic susceptibility testing was performed using aminoglycosides, β-lactams, fluoroquinolones, and sulfonamides. Aminoglycoside resistance genes were detected in strains with at least one aminoglycoside resistance gene using conventional/multiplex PCR. Results: Aminoglycoside resistance was observed in 46.8% (101/216) of strains. The resistance rates were respectively 45.37% for Tobramycin, 32.40% for Gentamicin, 14.81% for Kanamycin, 2.31% for Netilmicin, 1.84% for Neomycin, and 0.46% for Amikacin. PCR showed that 86 strains (85.15%) possessed the aac(3)-IIc gene, 71 strains or 70.30%) possessed the aac(6’)-Ib gene, and nine strains (8.91%) possessed the armA gene. Conclusion: Aminoglycoside resistance in pathogenic E. coli strains is mainly due to the presence of the aac(3’)-IIc and aac(6’)-Ib genes. The presence of armA was first reported in Burkina Faso. Netilmicin, Neomycin and Amikacin are good therapeutic options for treating urinary tract and pus-forming infections.

PCR Detection of Virulence Genes Colv,Stxs and HlyE of Escherichia coli

[Objective] This study aimed to explore the presence of three causative genes Colv,Stxs and HlyE of the pathogenic E.coli from chickens,pigs and food.[Method] By using 44 E.coli strains from chickens,24 from pigs and 26 from food as the experimental materials,virulence genes Colv,Stxs（stx2,stx2e） and HlyE were detected with polymerase chain reaction（PCR） method.[Result] Among all the E.coli strains,the detection rate of Colv was 25% from chickens,4.2% from pigs,and 0 from food;the detection rate of Stx2（Stx2e） from all E.coli strains was 0;the detection rate of HlyE was 2.27% from chickens,0 from pigs,and 11.5% from food.[Conclusion] Virulence gene Colv shows relatively high carrying rate in E.coli from chickens and pigs;HlyE also shows a certain degree of presence in E.coli from chickens and food.

Detection and Sequence Analysis of Escherichia coli Virulence Genes

[Objective] This study aimed to explore the pathogenic mechanism of E., cherichia coll. [Method] An E. coil strain isolated from raccoon dogs in vivo was studied, which had been identified, PCR was used to detect the gene of irp2 （301 bp） and fyuA （953 bp） related to E. coil virulence and PCR products were s, quenced. [Result] The genes of irp2 and fyuA were successfully amplified in boi strains isolated from raccoon dogs. Compared with the GenBank, the identity of tTr irp2 gene sequence and the fyuA gene sequence of the strain reached 98.5% 99.2% and 98.9%-100% respectively. Compared with each other, the identity of tt- two gene sequences of irp2 was 99.3%, and that between the two fyuA gene se quences was 98.9%. [Conclusion] This study provided scientific experimental data fi E. coil pathogenicity, prevention, diagnosis and treatment.

献血者HEV感染合并HBV感染的特征分析

目的探讨合肥地区献血者中戊型肝炎病毒合并乙型肝炎病毒感染情况与特征分析,分析其与HBsAg/HBV DNA检测结果的关系。方法随机抽取2021年7月1日—2023年2月25日无偿献血者标本1301份纳入研究对象,根据HBsAg和HBV DNA检测结果将标本分为3组,HBsAg阳性组169份标本、HBsAg阴性组102份标本、合格组1030份标本分别采用酶联免疫吸附试验(ELISA)检测血浆中HEV Ag、抗HEV-IgM和抗HEV-IgG。依据抗HEV抗体检测结果采用RT-PCR法对合格组标本100份、HBsAg阳性组标本20份、HBsAg阴性组标本30份进行HEV RNA检测。分析3组献血者中抗HEV-IgM和抗HEVIgG检测阳性献血者基本情况进行统计分析。结果3组1301份标本HEV Ag检测均为阴性。HBsAg阴性组检出抗HEV阳性率为22.55%,与HBsAg阳性组相比(22.55%vs 17.75%)差异无统计学意义(P>0.05);但与合格组相比(22.55%vs 13.79%),差异有统计学意义(P<0.05)。HBsAg阳性组和合格组均检出抗HEV-IgG+IgM抗体,阳性率分别为1.18%和0.29%,且合格组检出抗HEV-IgM抗体阳性率为0.39%。留取3组150份标本未检出HEV RNA。HBsAg阴性组随着献血者年龄的增长检出抗HEV抗体阳性率有升高趋势,但差异无统计学意义(P>0.05)。HBsAg阳性组和合格组抗-HEV抗体阳性率在41~50岁人群最高,分别为27.27%和27.04%,其次是51~55岁人群。1301份标本检出抗HEV抗体阳性男性献血者151人,阳性率16.74%,女性45人,阳性率11.28%,检出抗HEV阳性男女人数之比为3.5∶1,差异有统计学意义(P<0.05)。结论合肥地区献血者中存在HEV感染合并HBV感染,多为既往感染,也存在急性感染,HBV隐匿感染状态中HEV感染者居多。

Evidence and Potential Antibacterial Mechanism of Chinese Traditional Medicine Compounds for the Development of E. coli

Astragalus membranaceus (huangqi), Allium sativum (garlic), Cinnamomum cassia (cinnamon), and Dolichos lablab L. (white hyacinth bean) are the traditional Chinese herbs that were used in prescriptions in treating diarrhea caused by bacterial infection. These herbs are relatively safe for use and investigation. This study aimed to investigate the effects of Astragalus membranaceus, Allium sativum, Cinnamomum cassia, and Dolichos lablab L. on the metabolism of Escherichia coli (E. coli). The growth rate of E. coli was monitored under the influence of each herb, revealing that Astragalus membranaceus and Allium sativum exhibited significant antibacterial activity, whereas Cinnamomum cassia and Dolichos lablab L. demonstrated moderate inhibitory effects on E. coli growth. Further inhibition zone testing allowed for the evaluation of each herb’s potency and the number of generations required for E. coli to develop resistance. Additionally, the impact of the four herbs on the expression of outer membrane protein A (OmpA) in E. coli was examined by using qPCR. The findings revealed that Astragalus membranaceus acted as a sustainable bactericide by inhibiting the growth and metabolism of E. coli MG1655 through the suppression of OmpA expression. These results suggest that Astragalus membranaceus has potential as a natural antimicrobial agent for treating E. coli infections.

Genotyping Characteristics of Human Fecal Escherichia coli and Their Association with Multidrug Resistance in Miyun District, Beijing

Objective To explore the genotyping characteristics of human fecal Escherichia coli(E. coli) and the relationships between antibiotic resistance genes(ARGs) and multidrug resistance(MDR) of E. coli in Miyun District, Beijing, an area with high incidence of infectious diarrheal cases but no related data.Methods Over a period of 3 years, 94 E. coli strains were isolated from fecal samples collected from Miyun District Hospital, a surveillance hospital of the National Pathogen Identification Network. The antibiotic susceptibility of the isolates was determined by the broth microdilution method. ARGs,multilocus sequence typing(MLST), and polymorphism trees were analyzed using whole-genome sequencing data(WGS).Results This study revealed that 68.09% of the isolates had MDR, prevalent and distributed in different clades, with a relatively high rate and low pathogenicity. There was no difference in MDR between the diarrheal(49/70) and healthy groups(15/24).Conclusion We developed a random forest(RF) prediction model of TEM.1 + baeR + mphA + mphB +QnrS1 + AAC.3-IId to identify MDR status, highlighting its potential for early resistance identification. The causes of MDR are likely mobile units transmitting the ARGs. In the future, we will continue to strengthen the monitoring of ARGs and MDR, and increase the number of strains to further verify the accuracy of the MDR markers.

Escherichia coli Pathotypes in Children with Acute Diarrhea in an Informal Settlement in Nairobi, Kenya

Diarrhea is among the leading causes of morbidity and mortality in children aged Escherichia coli (DEC) accounts for 30% - 40% of childhood diarrhea cases. To identify the pathotypes involved in diarrheal outbreaks in Kenya, we analyzed archived E. coli isolates from children E. coli confirmation and antimicrobial susceptibility testing were done using the VITEK®2 instrument. Pathotype identification was performed via conventional polymerase chain reaction. Of 175 E. coli isolates, 48 (27%) were DEC pathotypes, with enteroaggregative E. coli (EAEC) predominating (71%, 34/48). Enterohemorrhagic (EHEC) and enteropathogenic E. coli (EPEC) represented 19% and 10% of isolates, respectively. Enteroinvasive and enterotoxigenic pathotypes were not identified. All DEC isolates were susceptible to amikacin, ertapenem, imipenem, meropenem and tigecycline. Conversely, most (>80%) isolates were resistant to ampicillin, ampicillin-sulbactam and sulfamethoxazole-trimethoprim. Half of all EAEC and EPEC strains were resistant to cefazolin while half of EHEC isolates were resistant to ciprofloxacin and moxifloxacin. In total, 18 resistance phenotypes were identified with “ampicillin-cefazolin-ampicillin/ sulbactam-sulfamethoxazole/trimethoprim” predominating (33%, 16/48). The majority (81%) of DEC isolates were multidrug-resistant, with extended-spectrum beta-lactamase production identified in 8% of these isolates. This study highlights the predominance of Enteroaggregative E. coli and multidrug resistance of DEC pathotypes. Studying the epidemiology of diarrheal disease and antimicrobial resistance surveillance, will aid in identifying dominant etiological agents of diarrhea and newly emerging resistant strains in informal settlements.

2种氟喹诺酮类抗生素与群体感应抑制剂对E.coli的联合毒性效应

抗生素滥用带来严重的细菌耐药性,威胁生态环境和人体健康。群体感应抑制剂(quorum sensing inhibitors,QSIs)作为一种理论上难以引发细菌耐药性的新型潜在抗生素替代品,被建议单独使用或与传统抗生素联合使用。因此,考察抗生素与QSIs联合作用效应及其作用机理对其在环境中可能产生的联合暴露风险评估具有重要的参考意义。以应用较广泛的2种氟喹诺酮类药物氧氟沙星(ofloxacin,OFL)、左氧氟沙星(levofloxacin,LEV)和1种新型抗菌剂群体感应抑制剂4-羟基-2,5-二甲基-3(2H)呋喃酮(4-hydroxy-2,5-dimethyl-3(2H)-furanone,HDMF)为研究对象,运用直接均分法和均匀设计射线法分别设计3个二元和1个三元混合物体系,每个体系包含5条具有不同组分浓度比的射线。应用时间毒性微板分析法测定3种药物及其混合物体系对大肠杆菌(Escherichia coli,E.coli)的毒性,应用拟合归零法分析混合物的毒性相互作用及相互作用强度,采用分子间对接技术来探讨可能存在的作用机理。结果表明,HDMF、OFL、LEV对E.coli均具有浓度、时间依赖毒性,以半数效应浓度负对数为毒性指标,3种药物在同一暴露时间毒性顺序:LEV>OFL>HDMF。3种药物的二元混合物体系相互作用类型有拮抗/协同作用,而三元混合物体系的作用类型为协同作用,且作用类型和强度受混合物组分、暴露时间和浓度影响。氟喹诺酮类药物混合物体系中,因药物竞争结合蛋白点位而呈现出拮抗作用。在氟喹诺酮类药物和QSIs混合体系中,QSIs会破坏细菌的生物膜,使氟喹诺酮类药物更容易接触细菌造成损伤,从而呈现协同作用。但随着暴露时间的延长,氟喹诺酮类药物会对DNA造成损伤进而减少QSIs作用蛋白的产生,呈现出拮抗作用。

婴儿食物过敏的临床症状及血清特异性免疫球蛋白E检测结果分析

目的了解不同过敏症状患儿的食物过敏原,为婴儿食物过敏的防治提供参考依据。方法选取2022年1月至12月间于长沙市妇幼保健院儿童保健中心体检中因过敏症状采用免疫印迹法进行血清特异性免疫球蛋白E(sIgE)检测的849例婴儿为研究对象。按不同年龄将婴儿分为<6月龄与≥6月龄;根据过敏的临床症状及病史等,将其分为皮肤症状(262例)、消化道症状(113例)、营养不良症状(56例)、呼吸道症状(58例)、混合症状(360例)。对不同年龄、不同性别婴儿的食物过敏原及血清sIgE检测阳性分布情况进行比较分析。结果在849名婴儿中,有皮肤症状者占30.9%(262/849),消化道症状者占13.3%(113/849),营养不良者占6.6%(56/849),呼吸道症状者占6.8%(58/849),混合症状者占42.4%(360/849);其中,男婴占57.8%(491/849),女婴占42.2%(358/849),不同性别婴儿过敏症状的分布比较差异无统计学意义(P>0.05);<6月龄者占23.8%(202/849),≥6月龄者占76.2%(647/849),不同年龄婴儿过敏症状的分布比较差异有统计学意义(χ^(2)=49.303,P<0.001)。在849名婴儿中,食物过敏原血清sIgE检测阳性者占51.7%(439/849),阴性者占48.3%(410/849);其中,男婴食物过敏原血清sIgE检测阳性者占58.3%(256/439),女婴阳性者占41.7%(183/439),不同性别婴儿食物过敏原血清sIgE检测阳性的分布比较差异无统计学意义(P>0.05);<6月龄婴儿食物过敏原血清sIgE检测阳性占17.1%(75/439),≥6月龄者阳性占82.9%(364/439),不同年龄婴儿食物过敏原血清sIgE检测阳性的分布比较差异有统计学意义(χ^(2)=22.563,P<0.001)。不同年龄婴儿的食物过敏原数量比较差异有统计学意义(Z=-4.376,P<0.05),而不同性别婴儿的食物过敏原数量比较差异无统计学意义(P>0.05)。不同过敏症状食物过敏原血清sIgE检测阳性率及致敏种类的分布比较差异均无统计学意义(P>0.05)。在12种常见食物过敏原中,牛奶的血清sIgE检测阳性致敏程度最高可达3级,鸡蛋白的致敏程度最高可达6级;≥6月龄婴儿食物过敏原血清sIgE检测阳性率均高于<6月龄婴儿,但在不同年龄婴儿中,只有牛奶过敏原血清sIgE检测阳性率比较差异有统计学意义(χ^(2)=25.122,P<0.001),其他11种食物过敏原血清sIgE检测阳性率比较差异均无统计学意义(P>0.05)。结论婴儿早期食物过敏以皮肤症状为主,食物过敏原以牛奶、鸡蛋为主,血清sIgE检测对诊断IgE介导的食物过敏有意义,食物过敏的诊断仍需要综合其他因素分析判断。

Detection and Persistence of Clinical <i>Escherichia coli</i>in Drinking Water Evaluated by a Rapid Enzyme Assay and qPCR

The aims of this study were to evaluate two methods, qPCR and a chemiluminescent assay (ColiLight II), for rapid detection of E. coli in water, and to examine the survival and persistence of clinical E. coli in drinking water and biofilm using qPCR and ColiLight II. qPCR and ColiLight II were compared with a cultivation-based method (MPN), and survival and persistence of four clinical E. coli strains in water and biofilms on stainless steel (SS) and polyethylene (PE) surfaces were studied in a flow-through reactor with non-disinfected drinking water using ColiLight II, qPCR, ATP bioluminescence, and MPN. ColiLight II and qPCR correlated well with MPN. In drinking water, some clinical E. coli strains showed prolonged survival in drinking water flow-through systems, and persisted 3 - 3.4 times longer than the theoretical washout due to incorporation into biofilms. Strain specific attributes can significantly affect detection and persistence of E. coli in drinking water matrices.

De Novo Synthesis of Biopaint Using Transformed Bacteria: Analysis of Spectral Intensity Trends and Comparison to Commercial Paint

Background: Commercial paint pigments contain toxic heavy metals that harm humans and pollute the environment. To mitigate these harms, ecologically safe pigments are necessary. Objective: This experiment aims to create a biopaint de-novo using transformed Escherichia coli bacteria and compare it to commercial paint. Methods: Genetically engineered E. coli bacteria producing magenta pigment were grown in petri dishes. The pigment protein was extracted, filtered, and dehydrated into a crystalline powder. This was mixed with acrylic medium to make biopaint. The biopaint and commercial paint were applied on acrylic paper;red, green, blue, and total spectral intensities were measured daily under different testing conditions. Spectral intensity variability was measured and compared using the Coefficient of Variation (CV). Trends in spectral intensity were analyzed using regression analysis. Results: The differences in the CV of biopaint to commercial paint were less than 20% under all testing conditions. Spectral intensities for both biopaint and commercial paint did not show any significant change during the testing period under the conditions of room temperature, heat, and humidity. However, under the cold testing condition, biopaint showed a slight but statistically significant (p-value Conclusion: This experiment proves that E. coli-derived pigments can be used to make biopaint which has a similar durability to commercial paint as measured by the spectral intensities.

产ESBLs大肠埃希菌的临床分布和耐药率分析

目的 描述产超广谱β-内酰胺酶大肠埃希菌(ultraspectrum β-lactamase Escherichia coli,ESBL-EC)的感染患者信息、临床分布等特征,分析ESBL-EC耐药情况,为医院感染防控提供依据。方法 选取2017—2022年厦门市第三医院住院患者中确诊为ESBL-EC感染的病例,收集患者及ESBLEC菌株信息,分析其感染情况、临床特征及耐药性。结果 共确诊ESBL-EC感染患者929例,社区感染与医院感染的性别、年龄比较,差异有统计学意义(P<0.001)。ESBL-EC检出率为38.52%,检出率呈逐年上升趋势(P <0.001)。ESBLEC主要来源于普外科(19.38%)。ESBL-EC主要分离自尿液(43.38%)。ESBL-EC对氨曲南、呋喃妥因、复方新诺明、头孢唑林、头孢吡肟、妥布霉素6种抗菌药物,耐药率整体呈下降趋势,差异有统计学意义(P<0.05);对环丙沙星、头孢他啶、庆大霉素3种抗菌药物的耐药率呈上升趋势,差异有统计学意义(P<0.05)。医院感染ESBL-EC对氨苄西林、氨苄西林/舒巴坦、呋喃妥因、环丙沙星、庆大霉素、头孢菌素、妥布霉素、左氧氟沙星的耐药率均高于社区感染,差异有统计学意义(P<0.05)。结论 ESBL-EC检出率呈逐年增高的趋势。ESBL-EC耐药形势较为严峻,应加强各项感染防控措施,降低交叉感染风险;合理使用抗菌药物,减少ESBL-EC耐药菌株产生。

用于非线性超声检测的高频高功率E类功率放大器研究

超声波与金属的微小缺陷相互作用可产生非线性效应,由于非线性效应信号弱,在微小缺陷检测时必须采用高频高功率的发射装置来增强非线性效应信号强度。为此研究了一款高频大功率的超声驱动放大电路,该放大电路选用开关速度快、耐高压的氮化镓晶体管设计高效率的零电压开关(ZVS)型E类功率放大器,设计开关管保护电路、输入输出匹配电路以及可独立控制导通和关断驱动强度的栅极驱动电路,确保了高频高压大功率信号的高效输出。经测试,该E类功放驱动电路在工作频率为5 MHz,供电电压100 V时瞬时输出功率为223.9 W,峰值电压为150 V,直流转换效率为76.7%,表明该驱动电路可以用做高频大功率超声发射驱动。