The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacteri...The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.展开更多
BACKGROUND:The virulent factors of Escherichia coli(E.coli) play an important role in the process of pathopoiesis.The study aimed to compare drug-resistant genes and virulence genes between extended spectrum β-lactam...BACKGROUND:The virulent factors of Escherichia coli(E.coli) play an important role in the process of pathopoiesis.The study aimed to compare drug-resistant genes and virulence genes between extended spectrum β-lactamases(ESBLs)-producing E.coli and non-ESBLs-producing E.coli to provide a reference for physicians in management of hospital infection.METHODS: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,qacEA1-sull and 8 virulence genes(CNF2,hlyA,eaeA,VT1,est,bfpA,elt,and CNF1) were tested by polymerase chain reaction(PCR).RESULTS:Among the 96 E.coli isolates,the ESBLs-producing E.coli comprised 46(47.9%)strains and the non-ESBLs-producing E.coli consisted of 50(52.1%) strains.The detection rates of multiple drug-resistant strain,qacEA1-sull,CNF2,hlyA,eaeA,VT1,est,bfpA,elt,and CNF1 in 46ESBLs-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.coli strains,the positive rates of multiple drug-resistant strain,qacEA1-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.coli strains and the non-ESBLs-producing E.coli strains was statistically significant(P<0.05).CONCLUSION:The positive rate of multiple drug-resistant strains is higher in the ESBLsproducing 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.展开更多
To obtain the recombinant core domain of porcine zone pellucida 3β (cZP3β) for the further research on its functions Methods The nucleotide sequence region from 44 to 306 codons of pZP3β entire eDNA was obtained ...To obtain the recombinant core domain of porcine zone pellucida 3β (cZP3β) for the further research on its functions Methods The nucleotide sequence region from 44 to 306 codons of pZP3β entire eDNA was obtained by PCR and then was cloned into pET-3c vector. After being identified, recon was transformed into E.coli BL21 (DE3) pLysS and then induced by IPTG. Results The recombinant cZP3β was expressed in E. coli up to 15% of total cellular proteins, and was made sure by Western blot analysis. Conclusion The research on expression of core domain of pZP3β could benefit to further investigation of its immunogenicity and the development of antigen preparation.展开更多
The Escherichia coli(E.coli)is prevailing worldwide,but the epidemiology of E.coli infections feature regional distribution characteristics to some extent.E.coli,as a zoonotic pathogen,can be transferred from animals ...The Escherichia coli(E.coli)is prevailing worldwide,but the epidemiology of E.coli infections feature regional distribution characteristics to some extent.E.coli,as a zoonotic pathogen,can be transferred from animals to humans through food chain or via contact with wounds,causing a public health risk.We reported the swelling of proventriculus and tracheal bleeding following the death in two broiler chickens(Gallus gallus domesticus)from Beijing,China.To investigate whether a virus was involved in the infection,Madin Darby Bovine Kidney(MDCK)cells were co-cultured with supernatants of proventriculus,trachea and spleen homogenates.The avian leucosis virus was detected in the samples of proventriculus and trachea,but the avian influenza virus,the Newcastle disease virus and the avian infectious laryngotracheitis virus were not detected.E.coli isolates were resistant to almost all the antimicrobial as tested except for the combinations of amoxicillin/clavulanic acid and sulfamethoxazole/trimethoprim.PCR tests demonstrated the presence of antibiotic resistance genes in these E.coli isolates and further research revealed a novel gene profile with the presence of CTX-M-1,gyrA,gyrB,oqxA,oqxB,parC and Sul2 antibiotic resistance genes in a strain isolated from a proventriculus sample.These results demonstrated that the presence of antibiotic resistant E.coli would not necessarily cause outbreak of large-scale disease.However,when the bacteria carrying new antibiotic resistance genes enter the environment,it may result in the development of more virulent strains which will potentially impact human and animal health.展开更多
Background: Urinary tract infection caused by Escherichia coli is a frequently observed condition both in humans and animals. Uropathogenic E. coli (UPEC) has been shown to have a pathogenicity island that enables the...Background: Urinary tract infection caused by Escherichia coli is a frequently observed condition both in humans and animals. Uropathogenic E. coli (UPEC) has been shown to have a pathogenicity island that enables them to infect the urinary tract. Because there is little information about the presence of UPEC-associated virulent genes in animal isolates this work was carried out with the intent to enhance the understanding about the strains of E.coli that cause infections in animals. Results: We screened 21 E. coli strains isolated causing urinary tract infection in domestic animals. Primers were designed to amplify urinary infection-associated genes. Nine genes, papA, tcpC, fyuA, tpbA, Lma, hylA, picU, tonB, and flicC were then amplified and sequenced. Different from the human isolate CFT073, all the animals E. coli lack some of the pathogenesis-associated genes. Genes encoding for proteins used to scavenge iron appear not to be so necessary during animal infections as they are in human infection. In further investigation of phenotypic properties, it was observed that animal UPECs have significantly more impaired ability to form biofilms than human UPEC strain. Conclusions: This study identified significant differences between human and animal UPECs. This may have its roots in the fact that it is difficult to determine if an animal has symptoms. Future studies will focus on some of the observations.展开更多
Uropathogenic Escherichia coli is the common pathogen to cause urinary tract infections (UTIs) and have become multidrug-resistant (MDR) extended-spectrum β-lactamase (ESBL) producers. The differences in the antimicr...Uropathogenic Escherichia coli is the common pathogen to cause urinary tract infections (UTIs) and have become multidrug-resistant (MDR) extended-spectrum β-lactamase (ESBL) producers. The differences in the antimicrobial susceptibility, 5 bla genes, 12 virulence genes of 87 clinical ESBL-producing E. coli isolates and genomic variations and sequence types of 18 recurrent and repeated isolates from 9 patients were investigated. The 87 MDR-ESBL isolates collected mainly from indwelling urinary catheters (IUCs) and UTIs were highly resistant to fluoroquinolones, with over 50% of the isolates being resistant to cefepime and piperacillin/tazobactam and a few being resistant to carbapenem. These isolates carried at least two of the five bla genes examined, with the highest prevalence (87.4%) found for bla<sub>CTX-M</sub> (bla<sub>CTX-M3-like</sub> and bla<sub>CTX-M14-like</sub>), followed by bla<sub>CMY-2</sub> (80.5%) and bla<sub>SHV</sub> (56.3%). The predominant virulence genes were the fimbriae gene fimH and the toxin genes cnf1 and hlyA in blood isolates and the capsule gene kpsMTII in UTI and blood isolates. Over 80% of the isolates carried yersiniabactin and aerobactin of siderophores. In 18 isolates, the fluoroquinolone-resistant ST131 isolate of pulsotypes I and II with bla<sub>CTX-M-15</sub> was clonally disseminated in the hospital. The genomic plasticity of these ST131 occurred mainly through the conjugative plasmids with differences in replicon types A/C, I1, FIA, FIB and Y, size and number. In conclusion, MDR ESBL-producing E. coli isolates differed in virulence genes of UPEC and antibiotic resistance associated with the sources. Plasmid acquisition and chromosomal variations increase the spread of fluoroquinolone-resistant UPEC ST131 worldwide.展开更多
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, ...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.展开更多
Escherichia coli has become one of the most important causes of calf diarrhea.The aim of this study is to determine the patterns of antimicrobial resistance of E.coli isolates from six cattle farms and to identify pro...Escherichia coli has become one of the most important causes of calf diarrhea.The aim of this study is to determine the patterns of antimicrobial resistance of E.coli isolates from six cattle farms and to identify prominent resistance genes and virulence genes among the strains isolated from the diarrhea of calves.Antimicrobial susceptibility tests were performed using the disk diffusion method,and PCR was used to detect resistance and virulence genes.The prevalence of multidrug resistant(MDR)E.coli was 77.8%in dairy cattle and 63.6%in beef cattle.There were high resistance rates to penicillin(100%,100%)and ampicillin(96.3%,86.4%)in E.coli from dairy cattle and beef cattle.Interestingly,resistance rate to antimicrobials and distribution of resistance genes in£coli isolated from dairy cattle were higher than those in beef cattle.Further analysis showed that the most prevalent resistance genes were blojm and oodAl in dairy cattle and beef cattle,respectively.Moreover,seven diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,F41,K99 and STa)were present in the isolates from dairy cattle,with a prevalence ranging from 3.7%to 22.22%.Six diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,hylA and F41)were identified in the isolates from beef cattle,with a prevalence ranging from 2.27%to 63.64%.Our results provide important evidence for better exploring their interaction mechanism.Further studies are also needed to understand the origin and transmission route of£coli in cattle to reduce its prevalence.展开更多
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,...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.展开更多
Escherichia coli O157 : H7 is a foodborne pathogen that poses a major threat to public health. Epidemiologic investigations have identified dairy cows, especially calves, are the principal reservoir of E. coli O157 : ...Escherichia coli O157 : H7 is a foodborne pathogen that poses a major threat to public health. Epidemiologic investigations have identified dairy cows, especially calves, are the principal reservoir of E. coli O157 : H7. In this study, based on the results, E. coli O157 : H7 was the main cause of E. coli disease outbreak in late October, 2015, and more than 90% of newborn calves died of serious diarrhea. Through further experiments, the drug sensitivity and resistance of the strain, the expression of the virulence gene and virulence pathogenicity were studied. E. coli O157 : H7 isolates were resistant to 12 antibiotics including penicillin, tetracycline and ampicillin, and were sensitive to eight antibiotics including cefoperazone, ceftazidime and amikacin. Resistance genes included tetB, strB, aadB, aphA, floR, TEM and virulence genes included stx1, eaeA and hlyA. Using specific pathogen free mice, the result showed that the isolate was pathogenic with a median lethal dose of 7.9×107 CFU · mL-1. This study described the pathogenesis and clinical manifestations of E. coli O157 : H7 infection. These results guided the use of antibiotics in prevent and control of bacterial infections in the future.展开更多
Rivers can act as reservoirs of highly resistant strains and facilitate the dissemination of resistance, virulence and integron 1 genes. A cross-sectional study was carried out where 318 water samples were collected (...Rivers can act as reservoirs of highly resistant strains and facilitate the dissemination of resistance, virulence and integron 1 genes. A cross-sectional study was carried out where 318 water samples were collected (53 from each site) and from the samples, 318 E. coli isolates were analysed for resistance genes, virulence genes and integron 1 using Polymerase Chain Reaction. 22% of the isolates had blaTEM, 33% had blaCTX-M and 28% had blaCMY. Prevalence of typical Enteropathogenic E. coli strains (carrying both eae and bfp genes) was 5% while the prevalence of atypical Enteropathogenic E. coli (carying only eae) was 1.8%. The prevalence of Enteroaggregative E. coli carrying the aggr genes was 11%. The prevalence of Enterotoxigenic E. coli encoding only lt toxin was 16 (5%) and while those carrying only st toxin was 6.9%. The prevalence of Enteroinvasive E. coli strains encoding as IpaH was 5% while that of strains, adherent invasive E. coli, carrying adherent invasive gene inv was 8.7%. 36% isolates were positive for class 1 integrons which were mostly isolated near the sewage effluent from waste treatment plant. Anthropogenic activities and close proximity to sewage treatment plant were found to play a key role in pollution of water body and accumulation of resistance and virulence genes. These results suggest that waste treatment plant may act as reservoir of resistance, virulence and integron 1 genes and is a potential risk to human and animal health in the region.展开更多
Minipreparation (MiniPrep) analysis is an essential step for obtaining a recombinant plasmid that carries a DNA insert containing a gene of interest. The most commonly used method for this involves cultivation of tran...Minipreparation (MiniPrep) analysis is an essential step for obtaining a recombinant plasmid that carries a DNA insert containing a gene of interest. The most commonly used method for this involves cultivation of transformed Escherichia coli (E. coli) in liquid medium, brief centrifugation for precipitation of bacterial pellets, and subsequent lysis of the pellets. This process is time-consuming and laborious, especially when the sample number is high. Here, we describe a more convenient method for MiniPrep analysis that utilizes solid medium-based cultivation of bacteria.展开更多
基金Fundação de Amparo a Pesquisa do Estado de São Paulo(FAPESP)and the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq),São Paulo,Brazil for PhD scholarship(Process N°.141086/2015-7)financial support(Process No.870243/1997-7).
文摘The UV irradiation is used for removing Antibiotic Resistant Bacteria(ARB)and Antibiotic Resistance Genes(ARG)from wastewater treatment.Bacteriophages are viruses that infect within bacteria,are recognized for bacterial control.The influence of some parameters in quantification and performance influencing of pathogen demobilization could be considered in disinfection of wastewater.The comparison of Polyvalent phage(NE1)versus Coliphage(NE4)in suppressing a bacterium Escherichia coli(NDM-1:b-lactam-resistant)with UV irradiation was observed the efficacy in reduction of cells in the disinfection and parameter process.The results with the effect of UV-C irradiation on NDM-1 infected with 1%of NE4 showed a decrease of cells from 8×10^(6)to 2×10^(5)in 60 min with UV-C dose.The NDM1(E.coli)was infected with 1%of NE4(Polyvalent Phage)under magnetic stirring for 1 h,the cells count was 8×10^(6).After 1 h in UV-C e×posure,the cells number reached 3×10^(5).The NDM1 that was e×posed in 1 h of UV-C irradiation and then was infected with 1%of NE4.Cells counting were done 24 h after this procedure.These cells were e×posed in UV-C and showed a reduction in the number of cells from 1×10^(8)to 4×10^(5)after 60 min.The results indicate that bacteriophages can mitigate bacteria species,and combined the conventional water disinfection technologies that can support the microbial safety control strategies.
文摘BACKGROUND:The virulent factors of Escherichia coli(E.coli) play an important role in the process of pathopoiesis.The study aimed to compare drug-resistant genes and virulence genes between extended spectrum β-lactamases(ESBLs)-producing E.coli and non-ESBLs-producing E.coli to provide a reference for physicians in management of hospital infection.METHODS: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,qacEA1-sull and 8 virulence genes(CNF2,hlyA,eaeA,VT1,est,bfpA,elt,and CNF1) were tested by polymerase chain reaction(PCR).RESULTS:Among the 96 E.coli isolates,the ESBLs-producing E.coli comprised 46(47.9%)strains and the non-ESBLs-producing E.coli consisted of 50(52.1%) strains.The detection rates of multiple drug-resistant strain,qacEA1-sull,CNF2,hlyA,eaeA,VT1,est,bfpA,elt,and CNF1 in 46ESBLs-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.coli strains,the positive rates of multiple drug-resistant strain,qacEA1-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.coli strains and the non-ESBLs-producing E.coli strains was statistically significant(P<0.05).CONCLUSION:The positive rate of multiple drug-resistant strains is higher in the ESBLsproducing 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.
基金This study was supported by the Science & Technology Plan (No. 2001C12001) of Guangdong Province,P.R. China
文摘To obtain the recombinant core domain of porcine zone pellucida 3β (cZP3β) for the further research on its functions Methods The nucleotide sequence region from 44 to 306 codons of pZP3β entire eDNA was obtained by PCR and then was cloned into pET-3c vector. After being identified, recon was transformed into E.coli BL21 (DE3) pLysS and then induced by IPTG. Results The recombinant cZP3β was expressed in E. coli up to 15% of total cellular proteins, and was made sure by Western blot analysis. Conclusion The research on expression of core domain of pZP3β could benefit to further investigation of its immunogenicity and the development of antigen preparation.
基金Yellow River Conservancy Technical Institute(HYJG[2019]7)Innovation Program of Chinese Academy of Sciences(KSCX2-EW-Z-4)Science and technology development plan of Kaifeng in 2020(BKW[2019]95)as well as National Natural Sciences Foundation of China(31101806).
文摘The Escherichia coli(E.coli)is prevailing worldwide,but the epidemiology of E.coli infections feature regional distribution characteristics to some extent.E.coli,as a zoonotic pathogen,can be transferred from animals to humans through food chain or via contact with wounds,causing a public health risk.We reported the swelling of proventriculus and tracheal bleeding following the death in two broiler chickens(Gallus gallus domesticus)from Beijing,China.To investigate whether a virus was involved in the infection,Madin Darby Bovine Kidney(MDCK)cells were co-cultured with supernatants of proventriculus,trachea and spleen homogenates.The avian leucosis virus was detected in the samples of proventriculus and trachea,but the avian influenza virus,the Newcastle disease virus and the avian infectious laryngotracheitis virus were not detected.E.coli isolates were resistant to almost all the antimicrobial as tested except for the combinations of amoxicillin/clavulanic acid and sulfamethoxazole/trimethoprim.PCR tests demonstrated the presence of antibiotic resistance genes in these E.coli isolates and further research revealed a novel gene profile with the presence of CTX-M-1,gyrA,gyrB,oqxA,oqxB,parC and Sul2 antibiotic resistance genes in a strain isolated from a proventriculus sample.These results demonstrated that the presence of antibiotic resistant E.coli would not necessarily cause outbreak of large-scale disease.However,when the bacteria carrying new antibiotic resistance genes enter the environment,it may result in the development of more virulent strains which will potentially impact human and animal health.
文摘Background: Urinary tract infection caused by Escherichia coli is a frequently observed condition both in humans and animals. Uropathogenic E. coli (UPEC) has been shown to have a pathogenicity island that enables them to infect the urinary tract. Because there is little information about the presence of UPEC-associated virulent genes in animal isolates this work was carried out with the intent to enhance the understanding about the strains of E.coli that cause infections in animals. Results: We screened 21 E. coli strains isolated causing urinary tract infection in domestic animals. Primers were designed to amplify urinary infection-associated genes. Nine genes, papA, tcpC, fyuA, tpbA, Lma, hylA, picU, tonB, and flicC were then amplified and sequenced. Different from the human isolate CFT073, all the animals E. coli lack some of the pathogenesis-associated genes. Genes encoding for proteins used to scavenge iron appear not to be so necessary during animal infections as they are in human infection. In further investigation of phenotypic properties, it was observed that animal UPECs have significantly more impaired ability to form biofilms than human UPEC strain. Conclusions: This study identified significant differences between human and animal UPECs. This may have its roots in the fact that it is difficult to determine if an animal has symptoms. Future studies will focus on some of the observations.
文摘Uropathogenic Escherichia coli is the common pathogen to cause urinary tract infections (UTIs) and have become multidrug-resistant (MDR) extended-spectrum β-lactamase (ESBL) producers. The differences in the antimicrobial susceptibility, 5 bla genes, 12 virulence genes of 87 clinical ESBL-producing E. coli isolates and genomic variations and sequence types of 18 recurrent and repeated isolates from 9 patients were investigated. The 87 MDR-ESBL isolates collected mainly from indwelling urinary catheters (IUCs) and UTIs were highly resistant to fluoroquinolones, with over 50% of the isolates being resistant to cefepime and piperacillin/tazobactam and a few being resistant to carbapenem. These isolates carried at least two of the five bla genes examined, with the highest prevalence (87.4%) found for bla<sub>CTX-M</sub> (bla<sub>CTX-M3-like</sub> and bla<sub>CTX-M14-like</sub>), followed by bla<sub>CMY-2</sub> (80.5%) and bla<sub>SHV</sub> (56.3%). The predominant virulence genes were the fimbriae gene fimH and the toxin genes cnf1 and hlyA in blood isolates and the capsule gene kpsMTII in UTI and blood isolates. Over 80% of the isolates carried yersiniabactin and aerobactin of siderophores. In 18 isolates, the fluoroquinolone-resistant ST131 isolate of pulsotypes I and II with bla<sub>CTX-M-15</sub> was clonally disseminated in the hospital. The genomic plasticity of these ST131 occurred mainly through the conjugative plasmids with differences in replicon types A/C, I1, FIA, FIB and Y, size and number. In conclusion, MDR ESBL-producing E. coli isolates differed in virulence genes of UPEC and antibiotic resistance associated with the sources. Plasmid acquisition and chromosomal variations increase the spread of fluoroquinolone-resistant UPEC ST131 worldwide.
基金funded by the National Pathogen Identification Network project and Research on Key Technologies of Intelligent Monitoring,Early Warning and Tracing of Infectious Diseases in Miyun。
文摘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.
基金This study was supported by the National Science and Technology Ministry(2014BAD13B03-1)the project supported by the Heilongjiang Province Farms General Administration of China(HNK135-04-03)This work was supported by a grant from the Heilongjiang Bayi Agricultural University Support Program for San Heng San Zong(TDJH202002).
文摘Escherichia coli has become one of the most important causes of calf diarrhea.The aim of this study is to determine the patterns of antimicrobial resistance of E.coli isolates from six cattle farms and to identify prominent resistance genes and virulence genes among the strains isolated from the diarrhea of calves.Antimicrobial susceptibility tests were performed using the disk diffusion method,and PCR was used to detect resistance and virulence genes.The prevalence of multidrug resistant(MDR)E.coli was 77.8%in dairy cattle and 63.6%in beef cattle.There were high resistance rates to penicillin(100%,100%)and ampicillin(96.3%,86.4%)in E.coli from dairy cattle and beef cattle.Interestingly,resistance rate to antimicrobials and distribution of resistance genes in£coli isolated from dairy cattle were higher than those in beef cattle.Further analysis showed that the most prevalent resistance genes were blojm and oodAl in dairy cattle and beef cattle,respectively.Moreover,seven diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,F41,K99 and STa)were present in the isolates from dairy cattle,with a prevalence ranging from 3.7%to 22.22%.Six diarrheagenic virulence genes(irp2,fyuA,Stx1,eoeA,hylA and F41)were identified in the isolates from beef cattle,with a prevalence ranging from 2.27%to 63.64%.Our results provide important evidence for better exploring their interaction mechanism.Further studies are also needed to understand the origin and transmission route of£coli in cattle to reduce its prevalence.
文摘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.
文摘Escherichia coli O157 : H7 is a foodborne pathogen that poses a major threat to public health. Epidemiologic investigations have identified dairy cows, especially calves, are the principal reservoir of E. coli O157 : H7. In this study, based on the results, E. coli O157 : H7 was the main cause of E. coli disease outbreak in late October, 2015, and more than 90% of newborn calves died of serious diarrhea. Through further experiments, the drug sensitivity and resistance of the strain, the expression of the virulence gene and virulence pathogenicity were studied. E. coli O157 : H7 isolates were resistant to 12 antibiotics including penicillin, tetracycline and ampicillin, and were sensitive to eight antibiotics including cefoperazone, ceftazidime and amikacin. Resistance genes included tetB, strB, aadB, aphA, floR, TEM and virulence genes included stx1, eaeA and hlyA. Using specific pathogen free mice, the result showed that the isolate was pathogenic with a median lethal dose of 7.9×107 CFU · mL-1. This study described the pathogenesis and clinical manifestations of E. coli O157 : H7 infection. These results guided the use of antibiotics in prevent and control of bacterial infections in the future.
文摘Rivers can act as reservoirs of highly resistant strains and facilitate the dissemination of resistance, virulence and integron 1 genes. A cross-sectional study was carried out where 318 water samples were collected (53 from each site) and from the samples, 318 E. coli isolates were analysed for resistance genes, virulence genes and integron 1 using Polymerase Chain Reaction. 22% of the isolates had blaTEM, 33% had blaCTX-M and 28% had blaCMY. Prevalence of typical Enteropathogenic E. coli strains (carrying both eae and bfp genes) was 5% while the prevalence of atypical Enteropathogenic E. coli (carying only eae) was 1.8%. The prevalence of Enteroaggregative E. coli carrying the aggr genes was 11%. The prevalence of Enterotoxigenic E. coli encoding only lt toxin was 16 (5%) and while those carrying only st toxin was 6.9%. The prevalence of Enteroinvasive E. coli strains encoding as IpaH was 5% while that of strains, adherent invasive E. coli, carrying adherent invasive gene inv was 8.7%. 36% isolates were positive for class 1 integrons which were mostly isolated near the sewage effluent from waste treatment plant. Anthropogenic activities and close proximity to sewage treatment plant were found to play a key role in pollution of water body and accumulation of resistance and virulence genes. These results suggest that waste treatment plant may act as reservoir of resistance, virulence and integron 1 genes and is a potential risk to human and animal health in the region.
文摘Minipreparation (MiniPrep) analysis is an essential step for obtaining a recombinant plasmid that carries a DNA insert containing a gene of interest. The most commonly used method for this involves cultivation of transformed Escherichia coli (E. coli) in liquid medium, brief centrifugation for precipitation of bacterial pellets, and subsequent lysis of the pellets. This process is time-consuming and laborious, especially when the sample number is high. Here, we describe a more convenient method for MiniPrep analysis that utilizes solid medium-based cultivation of bacteria.