Risk Factors for Prevalence of Enterotoxigenic Escherichia coli (ETEC) in Diarrheic and Non-diarrheic Neonatal and Weaner Pigs, South Africa

Enterotoxigenic Escherichio coli （ETEC） causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of South Africa were analyzed microbiologically against risk variables. Seventy-two percent of young pigs were found to be positive for ETEC toxin genes; estB （38.9%）, estB/STAP （25%）, and estB/LT （13.9%） were dominant. Risk factors for ETEC-diarrhea in pigs include： leaving sick piglets in a pen with healthy piglets [odds ratio （OR） = 33.52; P 〈 0.0001]; water spillage in pen （OR = 42.87; P 〈 0.0001）; hypothermic piglets （OR = 7.29; P 〈 0.0001）; runt piglets in pen with healthy littermates （OR = 3.65; P 〈 0.0001）; and prolonged use of antibiotics （OR = 3.05; P = 0.05）.

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.

Enterococcus faecium NCIMB 10415 administration improves the intestinal health and immunity in neonatal piglets infected by enterotoxigenic Escherichia coli K88

Background:This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB10415(E.faecium)on intestinal development,immunological parameters and gut microbiota of neonatal piglets challenged with enterotoxigenic Escherichia coli K88(ETEC).A total of 961-day-old sow-reared piglets were randomly assigned to 2 groups,with 48 piglets in each group.The piglets were from 16 litters(6 piglets each litter),and 3 piglets each litter were allocated to the E.faecium-supplemented(PRO)group,while the other 3 piglets were allocated to the control(CON)group.After colostrum intake,piglets in the PRO group were orally administrated with 3×10~9 CFU E.faecium per day for a period of one week.On day 8,one piglet per litter from each group was challenged(CON+ETEC,PRO+ETEC)or not(CON-ETEC,PRO-ETEC)with ETEC in a 2×2 factorial arrangement of treatments.On day 10(2 days after challenge),blood and tissue samples were obtained from piglets.Results:Before ETEC challenge,there were no significant differences for the average daily gain(ADG)and fecal score between the two groups of piglets.After ETEC challenge,the challenged piglets had greater fecal score compared to the non-challenged piglets,whereas E.faecium administration was able to decrease the fecal score.Piglets challenged with ETEC had shorter villous height,deeper crypt depth,and reduced number of goblet cells in the jejunum and decreased m RNA abundance of claudin-1 in the ileum,whereas increased the percentage of lymphocytes,concentrations of IL-1βin the plasma and TNF-αin the ileal mucosa,as well as increased the m RNA abundances of innate immunity-related genes in the ileum tissue.These deleterious effects caused by ETEC were partly alleviated by feeding E.faecium.In addition,piglets in PRO-ETEC group had decreased the percentage of CD8^+T cells of the peripheral blood when compared to those in CON-ETEC group.Moreover,E.faecium administration increased Verrucomicrobia at phylum level and decreased Bilophila at genus level.Conclusions:These results suggest that oral administration of E.faecium alleviated the intestinal injury and diarrhea severity of neonatal piglets challenged by ETEC,partly through improving the intestinal microbiota and immune response.This offers a potential strategy of dietary intervention against intestinal impairment by ETEC in neonatal piglets.

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.

The Truncated Gene cfaD′ Positively Regulates CFA/Ⅰ Expression of Enterotoxigenic Escherichia coli

The gene cluster cfaABCED’ of enterotoxigenic Escherichia coli, encoding the fimbriae which is called colonization factor antigen located on a plasmid. It is positively regulated by cfaR, a member of the AraC family, and the cfaD’ gene region, which is located downstream of cfaE and is homologous to cfaR, had been described as a truncated cryptic gene. In the present study we observed that the CFA/ fimbriae subunit, cfaB, was expressed in lower amount by the cfaABCED’ clone pNTP513 in host E. coli HB101. The expression of CFA/ diminished by deletion of cfaD’ gene region from pNTP513, and was restored by acquisition of cfaD’ in trans. Furthermore, CFA/ expression by cfaD’ deletion mutant, the cfaABCE clone, was remarkably increased by the presence of cfaD’ in trans in a topoisomerase A deficient strain of E. coli DM800. These data suggest that cfaD’ region is a functional region of gene, that regulates the CFA/ expression with cfaR by unknown mechanism.

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.

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.

Oleanolic acid improved intestinal immune function by activating and potentiating bile acids receptor signaling in E. coli-challenged piglets

Background Infection with pathogenic bacteria during nonantibiotic breeding is one of the main causes of animal intestinal diseases.Oleanolic acid(OA)is a pentacyclic triterpene that is ubiquitous in plants.Our previous work demonstrated the protective effect of OA on intestinal health,but the underlying molecular mechanisms remain unclear.This study investigated whether dietary supplementation with OA can prevent diarrhea and intestinal immune dysregulation caused by enterotoxigenic Escherichia coli(ETEC)in piglets.The key molecular role of bile acid receptor signaling in this process has also been explored.Results Our results demonstrated that OA supplementation alleviated the disturbance of bile acid metabolism in ETEC-infected piglets(P<0.05).OA supplementation stabilized the composition of the bile acid pool in piglets by regulating the enterohepatic circulation of bile acids and significantly increased the contents of UDCA and CDCA in the ileum and cecum(P<0.05).This may also explain why OA can maintain the stability of the intestinal microbiota structure in ETEC-challenged piglets.In addition,as a natural ligand of bile acid receptors,OA can reduce the severity of intestinal inflammation and enhance the strength of intestinal epithelial cell antimicrobial programs through the bile acid receptors TGR5 and FXR(P<0.05).Specifically,OA inhibited NF-κB-mediated intestinal inflammation by directly activating TGR5 and its downstream c AMP-PKA-CREB signaling pathway(P<0.05).Furthermore,OA enhanced CDCA-mediated MEK-ERK signaling in intestinal epithelial cells by upregulating the expression of FXR(P<0.05),thereby upregulating the expression of endogenous defense molecules in intestinal epithelial cells.Conclusions In conclusion,our findings suggest that OA-mediated regulation of bile acid metabolism plays an important role in the innate immune response,which provides a new diet-based intervention for intestinal diseases caused by pathogenic bacterial infections in piglets.

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.

Lactiplantibacillus plantarum L47 and inulin alleviate enterotoxigenic Escherichia coli induced ileal inflammation in piglets by upregulating the levels of a-linolenic acid and 12,13-epoxyoctadecenoic acid

Alternatives to antibiotics for preventing bacteria-induced inflammation in early-weaned farm animals are sorely needed. Our previous study showed that Lactiplantibacillus plantarum L47 and inulin could alleviate dextran sulfate sodium(DSS)-induced colitis in mice. To explore the protective effects of L. plantarum L47 and inulin on the ileal inflammatory response in weaned piglets challenged with enterotoxigenic Escherichia coli(ETEC), 28 weaned piglets were assigned into four groups, namely, CON group—orally given 10 mL/d phosphate buffer saline(PBS), LI47 group—orally given a mixture of 10 m L/d L. plantarum L47 and inulin, ECON group—orally given 10 mL/d PBS and challenged by ETEC, and ELI47group—orally given 10 mL/d L. plantarum L47 and inulin mixture and challenged by ETEC. The results demonstrated that the combination of L. plantarum L47 and inulin reduced inflammatory responses and relieved the inflammatory damage caused by ETEC, including ileal morphological damage, reduced protein expression of ileal tight junction, decreased antioxidant capacity, and decreased antiinflammatory factors. Transcriptome analysis revealed that L. plantarum L47 and inulin up-regulated the gene expression of phospholipase A2 group IIA(PLA2G2A)(P < 0.05) as well as affected alphalinolenic acid(ALA) metabolism and linoleic acid metabolism. Moreover, L. plantarum L47 and inulin increased the levels of ALA(P < 0.05), lipoteichoic acid(LTA)(P < 0.05), and 12,13-epoxyoctadecenoic acid(12,13-EpOME)(P < 0.05) and the protein expression of Toll-like receptor 2(TLR2)(P = 0.05) in the ileal mucosa. In conclusion, L. plantarum L47 and inulin together alleviated ETEC-induced ileal inflammation in piglets by up-regulating the levels of ALA and 12,13-EpOME via the LTA/TLR2/PLA2G2A pathway.

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.

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.

Prevalence and Antimicrobial Susceptibility Patterns of Escherichia Coli and Salmonella Typhi Isolated from Meat and Fish Samples from Selected Markets in a Metropolis and District in Ghana

Antimicrobial resistance has become a major challenge to the treatment and prevention of infections resulted in high morbidity and mortality globally. The inappropriate or abuse of antibiotics in animal farming is a key factor and thus led to the emergence of bacteria resistance and subsequent transfer of resistance genes to humans through the food chain. This study was to determine the prevalence of Salmonella typhi (S. typhi) and Escherichia coli (E. coli) isolated from various meat and fish samples and their susceptibility patterns against five commonly used antibiotics in Ghana (Ciprofloxacin 5 μg, Amoxicillin-clavulanic acid 20/10 μg, Imipenem 10 μg, Tetracycline 30 μg and Ceftazidime 30 μg). A total of 105 meat and fish samples were obtained from Tema and Prampram markets and bacteria isolation was carried out using appropriate selective microbial culture media and various biochemical methods for identification. The susceptibility patterns were determined using the Kirby-Bauer disk diffusion method and the results were interpreted using the CLSI 2020 guidelines. The results revealed a total of 56 bacterial isolates comprising 14 E. coli (25%) and 42 S. typhi (75%) isolated from the meat and fish samples. The antibiogram study showed a high resistance rate (88.64%) of S. typhi isolates to amoxicillin-clavulanic acid and tetracycline (97.73%). A moderate susceptibility of the isolates was obtained with imipenem (53.27%). All the E. coli isolates were resistant to tetracycline (100%) and demonstrated 78.57% and 50% resistance to amoxicillin-clavulanic acid and ceftazidime respectively. A total of 78.57% of the E. coli isolates and 68.18% of S. typhi isolates showed multidrug resistance. The multiple antibiotic resistance (MAR) index for all the isolates ranged from 0.2 to 1.00 with two S. typhi isolates and one E. coli isolate having a MAR index of 1.00 signifying total resistance to all the 5 antibiotics tested. In conclusion, E. coli and S. typhi isolated from the meat samples exhibited high rate of resistance against the antibiotics tested and thus possesses a major health risk due to inappropriate use of antibiotics in animal and fish farming and possible transfer of resistant strains to humans.