Antibacterial mechanism of kojic acid and tea polyphenols against Escherichia coli O157:H7 through transcriptomic analysis

Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E.coli O157:H7 than using either alone.This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level.The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E.coli O157:H7 found that acid resistance systems in kojic acid were activated,and the cell membrane and genomic DNA were destructed in the cells,resulting in“oxygen starvation”.The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP,which affected the bacteria's life metabolic process.Interestingly,we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA,respiration,tricarboxylic acid cycle.The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E.coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.

Preclinical and clinical evidence of the association of colibactinproducing Escherichia coli with anxiety and depression in colon cancer

BACKGROUND The association between the intestinal microbiota and psychiatric disorders is becoming increasingly apparent.The gut microbiota contributes to colorectal carcinogenesis(CRC),as demonstrated with colibactin-producing Escherichia coli(CoPEC).AIM To evaluate the association between CoPEC prevalence and anxiety-and depressive-like behaviors with both preclinical and clinical approaches.METHODS Patients followed after a CRC surgery and for whom the prevalence of CoPEC has been investigated underwent a psychiatric interview.Results were compared according to the CoPEC colonization.In parallel C57BL6/J wild type mice and mice with a CRC susceptibility were chronically infected with a CoPEC strain.Their behavior was assessed using the Elevated Plus Maze test,the Forced Swimming Test and the Behavior recognition system PhenoTyper®.RESULTS In a limited cohort,all patients with CoPEC colonization presented with psychiatric disorders several years before cancer diagnosis,whereas only one patient(17%)without CoPEC did.This result was confirmed in C57BL6/J wildtype mice and in a CRC susceptibility mouse model(adenomatous polyposis colimultiple intestinal neoplasia/+).Mice exhibited a significant increase in anxiety-and depressive-like behaviors after chronic infection with a CoPEC strain.CONCLUSION This finding provides the first evidence that CoPEC infection can induce microbiota-gut-brain axis disturbances in addition to its procarcinogenic properties.

The virulence regulator AbsR in avian pathogenic Escherichia coli has pleiotropic effects on bacterial physiology

Avian pathogenic Escherichia coli(APEC)belonging to extraintestinal pathogenic E.coli(ExPEC)can cause severe infections in extraintestinal tissues in birds and humans,such as the lungs and blood.MprA(microcin production regulation,locus A,herein renamed AbsR,a blood survival regulator),a member of the MarR(multiple antibiotic resistance regulator)transcriptional regulator family,governs the expression of capsule biosynthetic genes in human ExPEC and represents a promising druggable target for antimicrobials.However,a deep understanding of the AbsR regulatory mechanism as well as its regulon is lacking.In this study,we present a systems-level analysis of the APEC AbsR regulon using ChIP-Seq(chromatin immunoprecipitation sequencing)and RNA-Seq(RNA sequencing)methods.We found that AbsR directly regulates 99 genes and indirectly regulates 667 genes.Furthermore,we showed that:1)AbsR contributes to antiphagocytotic effects by macrophages and virulence in a mouse model for systemic infection by directly activating the capsular gene cluster;2)AbsR positively impacts biofilm formation via direct regulation of the T2SS(type II secretion system)but plays a marginal role in virulence;and 3)AbsR directly upregulates the acid tolerance signaling system EvgAS to withstand acid stress but is dispensable in ExPEC virulence.Finally,our data indicate that the role of AbsR in virulence gene regulation is relatively conserved in ExPEC strains.Altogether,this study provides a comprehensive analysis of the AbsR regulon and regulatory mechanism,and our data suggest that AbsR likely influences virulence primarily through the control of capsule production.Interestingly,we found that AbsR severely represses the expression of the type I-F CRISPR(clustered regularly interspaced short palindromic repeats)-Cas(CRISPR associated)systems,which could have implications in CRISPR biology and application.

Prevalence of Drug Resistant Uropathogenic Escherichia coli from Immunocompromised Diabetic Patients Attending Selected Health Facilities in Benue State

Escherichia coli is the commonest bacterial uropathogen of UTIs, the commonest infections in immunocompromised diabetic patients. Better understanding of their main resistance mechanisms to commonly used antibacterial agents will help to reduce the burden of this infection. The prevalence of drug resistant uropathogenic Escherichia coli isolates from immunocompromised diabetic patients attending selected health facilities in Benue State was investigated. Two hundred and ninety-six midstream urine samples were collected for both study and control diabetic patients. Bacterial isolation was done using semi-quantitative method. Drug resistant Escherichia coli were identified as multidrug resistant (MDR), extensive drug resistant (XDR) and pan-drug resistant organisms (PDR). Statistical significance was considered at p E. coli isolates from the study and control subjects with overall prevalence of 20.9% and 8.4% respectively. The isolates were highly resistant to penicillin (ampicillin), monobactam (aztreonam), older quinolone (nalidixic acid) whereas the majority of them showed high susceptibility to aminoglycoside (streptomycin), cephalosporin (cefotaxime) and carbapenem (imipenem). None showed complete susceptibility to all the tested antibiotics. Twenty-five E. coli were identified in this MDR, eight, XDR while 5 were PDR. High numbers of drug resistant E. coli isolates were identified in the study group of which 25 were MDR, 8 XDR while 5 were PDR isolates. High prevalence of UTI and drug resistant isolates occur in diabetic patients with hyperglycemic condition.

Impact of Genetic Diversity of Uropathogenic Escherichia coli and Klebsiella pneumoniae Strains on the Dissemination of Extended Spectrum Beta-Lactam Resistance Genes in Côte d’Ivoire

The increase and spread of bacterial resistance to extended-spectrum beta-lactam antibiotics are reported in many infections and are a real public health problem worldwide. Drug pressure is a factor that favors the emergence of a population of better adapted bacteria. However, there is no literature highlighting the genetic diversity and evolutionary structure of E. coli and K. pneumoniae in an environment with high selection pressure in Côte d’Ivoire. The objective of this study was to evaluate the genetic diversity of E. coli and K. pneumoniae strains circulating at the HKB Hospital in Abobo and at the Daloa Regional Hospital and its impact on the dissemination of extended spectrum beta-lactam resistance genes. A total of 39 strains isolated from the urinary tract of infected patients, including 30 strains of E. coli and 9 strains of K. pneumoniae were studied. A total of 39 strains isolated from the urinary tract of infected patients, including 30 strains of E. coli and 9 strains of K. pneumoniae were studied. From genomic DNA extracts, ESBL resistance genes were amplified by PCR and sequenced, in addition to genetic typing by ERIC-PCR. The data obtained were submitted to genetic and bioinformatics analyses. The results have shown a genetic diversity important in E. coli and K. pneumoniae with diversity indexs (SID) ranging from 0.5 to 0.77. The genetic structure of the bacterial species studied has shown a clonal distribution of strains with clones expressing TEM-9 and CTX-M-15 variants. Also, this clonal structure was correlated with the spread of resistance genes in E. coli and K. pneumoniae. The spread of resistant clones is a factor that might limit the fight against antibiotic resistance.

Phytochemicals of Aloe barbadensis miller as Potential Inhibitors of Uropathogenic Escherichia coli for Urinary Tract Infection Therapy: An in Silico Approach

Urinary tract infections (UTIs) are common infections caused by normal skin or rectum bacteria that get into the urethra and infect the urinary tract. Although the infection can affect various parts of the tract, bladder infections are the most prevalent kind. Uropathogenic Escherichia Coli (UPEC) is the most common pathogen associated with UTI development. Therefore, inhibiting the UPEC protein target (PDB ID: 8BVD) appears to be a promising therapeutic strategy. Therefore, in this study, molecular docking and dynamics were conducted to examine the antibacterial activity of Aloe barbadensis miller against UPEC bacteria. The Aloe barbadensis miller natural compounds licochalcone A, palmidin B and palmidin C were downloaded from PubChem with amoxicillin, which was used as a control drug and studied against the target molecule. The potential parameters examined were the docking scores, absorption, distribution, metabolism, excretion, toxicity (ADMET), bioavailability, root mean square deviation (RMSD), root mean square fluctuation (RMSF), hydrogen bonding, radius of gyration, and potential energy of the system. Docking scores showed that all ligands demonstrated an admirable candidature as an inhibitor to 8BVD molecule, and the score hierarchy is licochalcone A (-6.4 kcal/mol), palmidin C (-6.1 kcal/mol), palmidin B (-6.0 kcal/mol), and amoxicillin (-5.9 kcal/mol). All ligands appeared to have good drug-like properties and oral bioavailability. Molecular dynamic studies showed that all ligands exhibited an excellent nominee as inhibitors in their vicinity at 20 ns. However, there is a relatively high fluctuation of palmidin B compared with other compounds, which seems to be more stable. This work suggests that the selected phytoconstituents could be used as inhibitors of the 8BVD protein in the fight against UTIs. However, further investigation on the clinical and experimental validation of UTI treatment’s specific mechanisms and effects is still welcomed.

Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

Prevalence and Resistance Profile of Muenchen Cefotaximase (CTX-M) Group 1 Extended Spectrum Beta-Lactamase (ESBL)-Producing Uropathogenic Escherichia coli Strains in Dakar, Senegal

Background: Extended-spectrum beta-lactamase (ESBL) producing bacteria are a real public health problem, particularly in Africa. Among these ESBLs, there are the Muenchen Cefotaximase (CTX-M) described all over the world of which the most frequent is the CTX-M of group 1 particularly the CTX-M-15 variant. The objective of this study was to determine the prevalence of CTX-M group 1 ESBL-producing Escherichia coli strains and to test their antibiotics susceptibility profile. Methodology: A retrospective cross-sectional descriptive study was conducted to detect ESBL-secreting Escherichia coli strains by the synergy test. Identification of CTX-M type ESBL from group 1 was performed using the NG-Test CTX-M rapid diagnostic test (NG-Biotech®). Antibiotic susceptibility profile was determined using CA-SFM/EUCAST guidelines 2019. Data entry and statistical analysis were performed with Excel version 2010 and SPSS 20.0 respectively. Results: Eighty-two ESBL-producing Escherichia coli strains were tested. A group 1 CTX-M ESBL was detected in 75.6% of the strains (n = 62). These strains were highly resistant to cefotaxim (100%), aztreonam (100%), ceftazidim (85.4%) and cefepim (66.1%). They were also resistant to quinolones, gentamycin and sulfadoxine-trimethoprim combination. However, these strains showed sensitivity to ertapenem (100%), cefoxitin (69.3%), tigecyclin (66%), and amikacin (66.1%). The combination of piperacillin and tazobactam was active on 30.6% of the strains against 6.4% for the combination of amoxicillin and clavulanic acid. Conclusion: The CTX-M type ESBL of group 1 was present in the majority of ESBL-producing Escherichia colis trains. Despite the production of this enzyme conferring resistance to most beta-lactam antibiotics, some antibiotics remain active to treat infections caused by these germs.

亚胺培南对携带bla_(NDM-1)耐药基因的Escherichia coli耐药性及内膜secY、secE和secG转录水平的影响

目的探讨亚胺培南(IPM)对bla_(NDM-1)阳性Escherichia coli耐药性及其内膜secY、secE和secG转录水平的影响。方法以重组质粒pET28a(+)-bla_(NDM-1)转化菌株E.coli DH5α-bla_(NDM-1)和E.coli BL21(DE3)-bla_(NDM-1)为研究对象,在梯度浓度增加或撤消IPM暴露下传代培养菌株,检测17种抗生素对IPM暴露菌株的MIC值;SDS-PAGE凝胶电泳检测NDM-1表达;蛋白活性实验检测NDM-1活性;qRT-PCR检测bla_(NDM-1)及内膜secY、secE和secG转录水平。结果12μg/mL和0_(20)μg/mL IPM暴露的E.coli DH5α-bla_(NDM-1)菌株CFZ、CXM、FOX、CRO、CAZ、FEP等头孢类药物的MIC值(≥8μg/mL/≥8μg/mL、≥32μg/mL/≥32μg/mL、≥32μg/mL/≥32μg/mL、≥64μg/mL/=32μg/mL、≥32μg/mL/≥32μg/mL、≥32μg/mL/=8μg/mL)与0μg/mL IPM暴露MIC值(≤2μg/mL、=16μg/mL、≤8μg/mL、≤1μg/mL、≤4μg/mL、≤2μg/mL)相比均显著增高,而IPM和MEM的MIC值与0μg/mL IPM暴露(≤1μg/mL和≤1μg/mL)相比也显著增高(=8μg/mL/=8μg/mL和=4μg/mL/=4μg/mL)。12μg/mL和0_(20)μg/mL IPM暴露的E.coli BL21(DE3)-bla_(NDM-1)菌株FOX、CRO、FEP等头孢类药物的MIC值(≥32μg/mL/≥32μg/mL、≥64μg/mL/≥64μg/mL、=16μg/mL/=16μg/mL)与0μg/mL IPM暴露(≤8μg/mL、≤1μg/mL、≤2μg/mL)相比也均显著增高,而IPM和MEM的MIC值与0μg/mL IPM暴露(≤1μg/mL和≤1μg/mL)相比也均显著增高(≥16μg/mL/≥16μg/mL和≥16μg/mL/≥16μg/mL)。SDS-PAGE显示,随12μg/mL IPM暴露时间的延长,菌株NDM-1水解IPM活性增加。qRT-PCR显示,12μg/mL IPM暴露的E.coli DH5α-bla_(NDM-1)和E.coli BL21(DE3)-bla_(NDM-1)的bla_(NDM-1)、secY、secE和secG转录水平分别上调2.31/2.5、3.05/1.96、2.83/1.24和2.71/1.45倍。结论IPM可使bla_(NDM-1)阳性E.coli由碳青霉烯类敏感变为耐药且保持稳定,细菌内膜SecYEG跨膜通道蛋白参与菌株耐药性调控,这为认识抗生素压力下肠杆菌科细菌耐药性变化及指导临床合理用药提供理论支撑。

Phytogenic feed additives alleviate pathogenic Escherichia coli-induced intestinal damage through improving barrier integrity and inhibiting inflammation in weaned pigs

Background:This study was conducted to investigate the effects of each phytogenic feed additive(PFA;PFA1,bitter citrus extract;PFA2,a microencapsulated blend of thymol and carvacrol;PFA3,a mixture of bitter citrus extract,thymol,and carvacrol;PFA4,a premixture of grape seed,grape marc extract,green tea,and hops;PFA5,fenugreek seed powder)on the growth performance,nutrient digestibility,intestinal morphology,and immune response in weaned pigs infected with Escherichia coli(E.coli).Results:A total of 634-week-old weaned pigs were placed in individual metabolic cages and assigned to seven treatment groups.The seven treatments were as follows:1)NC;basal diet without E.coli challenge,2)PC;basal diet with E.coli challenge,3)T1;PC+0.04%PFA1,4)T2;PC+0.01%PFA2,5)T3;PC+0.10%PFA3,6)T4;PC+0.04%PFA4,7)T5;PC+0.10%PFA5.The experiments lasted in 21 d,including 7 d before and 14 d after the first E.coli challenge.In the E.coli challenge treatments,all pigs were orally inoculated by dividing a total of 10 mL of E.coli F18 for 3 consecutive days.The PFA-added groups significantly increased(P<0.05)average daily gain and feed efficiency and decreased(P<0.05)the fecal score at d 0 to 14 post-inoculation(PI).Tumor necrosis factorαwas significantly lower(P<0.05)in the PFA-added groups except for T1 in d 14 PI compared to the PC treatment.The T3 had a higher(P<0.05)immunoglobulin G and immunoglobulin A concentration compared to the PC treatment at d 7 PI.Also,T3 showed significantly higher(P<0.05)villus height:crypt depth and claudin 1 expression in ileal mucosa,and significantly downregulated(P<0.05)the expression of calprotectin compared to the PC treatment.Conclusions:Supplementation of PFA in weaned pigs challenged with E.coli alleviated the negative effects of E.coli and improved growth performance.Among them,the mixed additive of bitter citrus extract,thymol,and carvacrol showed the most effective results,improving immune response,intestinal morphology,and expression of tight junctions.

新疆喀什地区腹泻羔羊源产ESBL大肠杆菌的耐药性和系统进化分群研究

目的了解新疆喀什地区腹泻羔羊源产ESBL大肠杆菌的流行情况及耐药性,指导临床大肠杆菌病的防治。方法采集385份喀什地区腹泻羔羊肛周粪便,分离得到371株大肠杆菌,通过双纸片协同法筛选产ESBL大肠杆菌,对筛选到的菌株进行耐药基因鉴定、耐药性分析和系统进化分群研究。结果371株大肠杆菌中204株为产ESBL菌株,bla CTX-M、bla CTX-M-1G、bla CTX-M-9G和bla TEM耐药基因携带率分别为67.65%、69.12%、30.39%和63.73%,产ESBL阳性菌株均为多重耐药,对氨苄西林、头孢噻肟、庆大霉素、恩诺沙星、阿奇霉素、四环素、氯霉素、甲氧苄啶、氨曲南8种药物的耐药率为90.69%~100%,系统进化分群主要分布于A群和D群,其中A群菌株以10重耐药为主(41.11%),D群菌株以11重耐药为主(40%)。结论产ESBL菌株大肠杆菌是引起喀什地区羔羊腹泻的主要病原菌,以A群为主,且均为多重耐药。

羔羊源产ESBLs与非产ESBLs大肠埃希氏菌耐药性差异比较及基因型分析

为了明确宁夏地区羔羊源大肠埃希氏菌产超广谱β-内酰胺酶(ESBLs)与非产ESBLs大肠埃希氏菌的耐药性差异和相关基因携带情况差异,对实验室分离保存的87株羔羊源大肠埃希氏菌,采用ESBLs表型检测方法筛选产ESBLs的菌株和K-B纸片法进行药物敏感性试验,采用PCR法对分离株进行相关基因的检测。结果显示,87株大肠埃希氏菌中5株为产ESBLs菌株,检出率为5.75%。产ESBLs株对多数试验药物呈耐药性;而非产ESBLs菌株对多数试验药物敏感,仅对恩诺沙星、复方新诺明和红霉素耐药率超过50%。20种药物中,产ESBLs株大肠埃希氏菌对18种药物的耐药率极显著高于非产ESBLs菌株(P<0.01)。产ESBLs菌株携带blaCTX的阳性率极显著高于非产ESBLs菌株(P<0.01),产ESBLs菌株中的blaTEM和blaOXA基因的阳性率均高于非产ESBLs菌株,但差异不显著(P>0.05)。结果表明宁夏地区羔羊源大肠埃希氏菌产ESBLs菌株流行率低,产ESBLs菌株耐药性严重,且宁夏地区羔羊源ESBLs菌株优势基因型为blaCTX和blaTEM。

Comparison of extended spectrum β-lactamasesproducing Escherichia coli with non-ESBLsproducing E.coli:drug-resistance and virulence

The virulent factors of Escherichia coil （E.cofi） play an important role in the process of pathopoiesis. The study aimed to compare drug-resistant genes and virulence genes between extended spectrum β-1actamases （ESBLs）-producing E.coli and non-ESBLs-producing E.cofi to provide a reference for physicians in management of hospital infection. From October 2010 to August 2011,96 drug-resistant strains of E. coli isolated were collected from the specimens in Qingdao Municipal Hospital, Qingdao, China. These bacteria strains were divided into a ESBLs-producing group and a non-ESBLs-producing group. Drug sensitivity tests were performed using the Kirby-Bauer （K-B） method. Disinfectant gene, qacEAl-sull and 8 virulence genes （CNF2, hlyA, eaeA, VT1, est, bfpA, elt, and CNF1） were tested by polymerase chain reaction （PCR）. Among the 96 E.coli isolates, the ESBLs-producing E.coli comprised 46 （47.9%） strains and the non-ESBLs-producing E.cofi consisted of 50 （52.1%） strains. The detection rates of multiple drug-resistant strain, qacEAl-sull, CNF2, hlyA, eaeA,VT1, est, bfpA, elt, and CNF1 in 46 ESBLs-producing E.coli isolates were 89.1%, 76.1%, 6.5%, 69.6%, 69.6%, 89.1%, 10.9%, 26.1%, 8.7%, and 19.6%, respectively. In the non-ESBLs-producing E.cofi strains, the positive rates of multiple drug-resistant strain, qacEAl-sull, CNF2, hlyA, eaeA, VT1, est, bfpA, elt, and CNF1 were 62.0%, 80.0%, 16.0%, 28.0%, 64.0%, 38.0%, 6.0%, 34.0%, 10.0%, and 24.0%, respectively. The difference in the detection rates of multiple drug-resistant strain, hlyA and VT1 between the ESBLs-producing E.cofi strains and the non-ESBLs-producing E.cofi strains was statistically significant （P〈0.05）. The positive rate of multiple drug-resistant strains is higher in the ESBLs-producing strains than in the non-ESBLs-producing strains. The expression of some virulence genes hlyA and VT1 varies between the ESBLs-producing strains and the non-ESBLs-producing strains. Increased awareness of clinicians and enhanced testing by laboratories are required to reduce treatment failures and prevent the spread of multiple drug-resistant strains.

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。

Diarrheic Escherichia coli: A Predominant Etiological Agent of Gastroenteritis, a Case Study in Douala, Cameroon

Context: Gastroenteritis remains an infectious disease with high morbidity and mortality particularly in low incomes countries, where the capacity to search all etiological agents, especially pathogenic Escherichia coli, is very limited. We investigated the contribution of pathogenic Escherichia coli and their antibiotic resistance profiles in cases of gastroenteritis. Methods: A cross-sectional study was carried out on human stool samples from October 2021 to June 2022 at Laquintinie Hospital. Samples were received from patients of all age groups and screened for bacteriological and parasitological identification by microscopy, bacterial culture, biochemical identification, and antimicrobial susceptibility tests. Results: A total of 296 patients with gastroenteritis complaints, were enrolled in the study with ages ranging from 5 months to 90 years old (Median = 35.5;SD = 20.8). Among the samples analyzed, 1.7% (n = 5/296) were positive for parasites and 27% (n = 80/296) were positive for bacterial pathogens. Parasites were found in mono parasitism, mainly Entamoeba histolytica (60%;n = 3/5), followed by Trichomonas intestinalis (20%;n = 1/5), and Giardia intestinalis (20%;n = 1/5). Three species of bacterial pathogens were identified with no co-infection: diarrheic Escherichia coli (DEC), Salmonella sp, and Shigella sp with respective proportions of 90% (n = 72/80), 6.3% (n = 5/80), and 3.7% (n = 3/80). For antibiotic resistance profiles (ARPs) of the 72 isolates of DEC, high levels of resistance were observed globally with amoxicillin (93.1%;n = 67/72), followed by ciprofloxacin (75%;n = 54/72), and to trimethoprim + sulfamethazole (73.6%;n = 53/72). In contrast, DEC showed low resistance rates with nitrofurans (6.9%;n = 5/72) and imipenem (2.8%;n = 2/72). The strains had 56 distinct ARPs, of which 88.9% (n = 64/72) were MDR. Salmonella sp and Shigella sp showed high levels of resistance to amoxicillin and trimethoprim + sulfamethazole. Conclusion: These results emphasize the need to consider DEC as the main cause of consultation in cases of gastroenteritis and reiterate the urgent need to rationalize antibiotic use in Cameroon.

Pyogenic spondylitis caused by Escherichia coli: A case report and literature review

BACKGROUND Pyogenic spondylitis is often manifested as atypical low back pain and fever,which makes it easy to be confused with other diseases.Here we report a case of pyogenic spondylitis and describe the diagnosis and treatment based on the related literature.CASE SUMMARY The reported case suffered from pyogenic spondylitis caused by Escherichia coli and complicated with bacteremia and psoas abscess.Acute pyelonephritis was initially diagnosed due to atypical symptoms.Symptoms were improved from antibiotic treatment while developing progressive lower limb dysfunction.One month post the admission,the patient underwent anterior lumbar debridement+autogenous iliac bone graft fusion+posterior percutaneous screw-rod internal fixation,and received 6 wk of antibiotic treatment after the operation.Reexamination 4 mo post the operation showed that the patient had no evident pain in the waist,and walked well with no evident dysfunction of lower limbs.CONCLUSION Here we describe the application value of several imaging examinations,such as X-ray,computed tomography and magnetic resonance imaging,and certain tests like erythrocyte sedimentation rate and C-reactive protein in the clinical treatment of pyogenic spondylitis.This disease requires early diagnosis and treatment.Sensitive antibiotics should be used in early stages and surgical intervention should be taken if necessary,which may help for a speedy recovery and prevent the occurrence of severe complications.

Characterization of a bla_(CTX-M-3),bla_(KPC-2)and bla_(TEM-1B)co-producing IncN plasmid in Escherichia coli of chicken origin

An extensively drug-resistant(XDR)Escherichia coli strain 258E was isolated from an anal swab sample of a chicken farm of Anhui province in China.Genomic analyses indicated that the strain 258E harbors an incompatibility group N(IncN)plasmid pEC258-3,which co-produces bla_(CTX-M-3),bla_(KPC-2),bla_(TEM-1B),qnrS1,aac(6')-Ib-cr,dfrA14,arr-3,and aac(6')-Ib3.Multiple genome arrangement analyses indicated that pEC258-3 is highly homologous with pCRKP-1-KPC discovered in Klebsiella pneumoniae from a patient.Furthermore,conjugation experiments proved that plasmid pEC258-3 can be transferred horizontally and may pose a significant potential threat in animals,community and hospital settings.

农贸市场食品来源大肠埃希菌的耐药性及其ESBL耐药基因的研究

目的:调查云南省保山市农贸市场售卖畜禽肉蛋和蔬菜超广谱β-内酰胺酶(Extended-Spectrumβ-Lactamase,ESBL)大肠埃希菌污染情况,研究样品分离获得的大肠埃希菌ESBL耐药基因类型。方法:收集农贸市场食品样本,分离鉴定样品中的大肠埃希菌并进行药敏试验,扩增大肠埃希菌的ESBL基因,对扩增产物进行测序和同源性比对分析。结果:245份食品样本中分离获得大肠埃希菌75株,其中产ESBL大肠埃希菌25株。对ESBL耐药基因测序结果进行系统发育分析,发现耐药基因为CTX-M型,CTX-M-15序列有9株,占比为36%;CTX-M-14有16株,占比为64%。结论:肉类和蔬菜携带ESBL大肠埃希菌,多重耐药菌及其耐药基因可能通过食品在社区传播。

Construction of Escherichia coli by Metabolic Engineering for Synthesis of Mesaconic Acid

Mesaconic acid has a special chemical structure and can undergo a series of reactions such as polymerization and addition. It is an important chemical intermediate and widely used in material, chemical and other industries. The chemical synthesis of mesaconic acid requires nitric acid, which is dangerous and harmful to the environment. The production of mesaconic acid by microbial fermentation has the characteristics of low raw material price, high efficiency and strong specificity, and thus a strong industrial application prospect. Mesaconic acid is an intermediate product of glutamic acid degradation pathway of microorganisms such as Clostridium tetani. However, at present, few reports have been conducted on the production of mesaconic acid by metabolic engineering microorganisms. In this study, glutamate mutase(GLM) and 3-methylaspartate ammonialyase(MAL) from C. tetani were recombined and expressed in Escherichia coli, and the obtained strain, BL21(DE3)/pETDuet-1-MAL-mutS-mutE, achieved the yield of mesaconic acid of 1.06 g/L. Compared with the wild type, the yields of mesaconic acid from mutants G133A and G133S increased by 21% and 16%, respectively. After 24 h of flask fermentation, the yields of mesaconic acid reached 1.28 and 1.23 g/L, respectively. This study can provide reference for microbial synthesis of mesaconic acid.

Phenotypic and Genotypic Antibiotic Resistant Diarrheagenic Escherichia coli Isolated from Patients with Diarrhea in Ouagadougou, Burkina Faso

Background: The emergence and spread of multidrug-resistant bacteria have become a major public health problem worldwide, particularly in developing countries such as Burkina Faso. This study aims to determine phenotypic and genotypic antibiotic resistant diarrheagenic Escherichia coli (DEC) from patients with diarrhea in Ouagadougou, Burkina Faso. Methodology: Microbiological and biochemical analysis were done to detect two hundred and ninety-two (292) strains. The susceptibility of the strains to antibiotics was determined by the agar disc diffusion method. 16-plex-PCR assays were carried out to detect both virulence and resistance genes encoding betalactams, quinolones, phenicols, tetracyclines and virulence gene of DEC. Results: Diarrheagenic Escherichia coli was detected in 8% (23/292) of patients with diarrhea using the 16-plex-PCR and 39.1% (9/23) of the DEC detected carry at least one resistance gene. Resistance rate in disc diffusion test was 86.96% to tetracycline, 65.23% to cotrimoxazole, 17.4% to nalidixic acid, 17.4% to norfloxacin, 17.4% to ciprofloxacin, 13.04% to ceftriaxone, 13.04% to cefotaxime, 8.7% to gentamicin, 8.7% to Chloramphenicol, 0% to netilmicin. The prevalence of different resistance genes in the studied strains varied from 44.4% to 5.5%. The gene Tet coding for resistance to tetracycline was found in 8 strains (44.4%). The CatA gene coding for resistance to Chloramphenicol was detected in 38.9% of isolates. The qnrS, blaSHV and blaOXA genes were each detected in 5.5% of isolates. No strain hosts the qnrA, qnrB and blaTEM genes. Conclusion: This study identified β-lactams, quinolones, phenicols and tetracyclines resistance genes in DEC isolates from patients with diarrhea in Ouagadougou, Burkina Faso. These results indicate the need for a surveillance program to reduce the prevalence of resistance to Enterobacteriaceae strains in hospitals.