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Fang X, Miao S, Zhang Y, Chen Z, Lai Y, Yang Y, Cheng S, Fan S, Yang J, Zhang Y, Chen Z, Liu S. Green synthesis and characterization of an orally bioactive artemisinin-zinc nanoparticle with enhanced bactericidal activity. Colloids Surf B Biointerfaces 2024; 234:113660. [PMID: 38042107 DOI: 10.1016/j.colsurfb.2023.113660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/19/2023] [Accepted: 11/19/2023] [Indexed: 12/04/2023]
Abstract
The occurrence of multidrug-resistant bacteria necessitates the development of new antibacterial agents. This study synthesized artemisinin-zinc nanoparticles (AZ NPs) using a simple green method and investigated their physicochemical properties, antibacterial activity, and oral biological activity. A spherical shape morphology of AZ NPs was observed by scanning and transmission electron microscopy, with a particle size of 73 ± 2.604 nm. Energy dispersive spectrometry analysis showed that the AZ NPs consisted mainly of Zn, C, N, and O elements. According to differential scanning calorimeter analysis, the AZ NPs were stable up to 450 °C. Fourier-transform infrared spectroscopy revealed that artemisinin successfully bound to zinc acetate. The AZ NPs showed antibacterial activity against Salmonella and Escherichia coli, with a minimum inhibitory concentration of 0.056 mg/mL for both and minimum bactericidal concentrations of 0.21 and 0.11 mg/mL, respectively. The mechanisms by which AZ NPs mediate membrane damage were revealed by the downregulation of gene expression, and potassium ion and protein leakage. In vivo safety trials of these drugs revealed low toxicity. After AZ NPs were administered to infected mice, the intestinal bacteria decreased significantly, liver and kidney function were restored, histopathological damage to the liver and spleen were reduced, and the expression of inflammatory cytokines decreased. Therefore, AZ NPs have the potential as an oral antibacterial agent and can be used in antibiotic development and in the pharmaceutical industry.
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Affiliation(s)
- Xue Fang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China
| | - Shengnan Miao
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China
| | - Yan Zhang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China
| | - Zhuo Chen
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China
| | - Yonghao Lai
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China
| | - Yumeng Yang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China
| | - Siyuan Cheng
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China
| | - Shoudong Fan
- Dongwo Tongtai (Fengcheng) Bioengineering Co., Ltd, Dandong 118000, China
| | - Jiao Yang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China
| | - Yi Zhang
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China.
| | - Zeliang Chen
- Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University, Shenyang 110866, China; Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, Shenyang 110866, China.
| | - Shiwei Liu
- Department of Nephrology and Endocrinology, Wangjing Hospital, Chinese Academy of Chinese Medical Science, Beijing 100102, China.
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Khine NO, Wongsurawat T, Jenjaroenpun P, Hampson DJ, Prapasarakul N. Comparative genomic analysis of Colistin resistant Escherichia coli isolated from pigs, a human and wastewater on colistin withdrawn pig farm. Sci Rep 2023; 13:5124. [PMID: 36991093 PMCID: PMC10060365 DOI: 10.1038/s41598-023-32406-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/27/2023] [Indexed: 03/31/2023] Open
Abstract
In this study, genomic and plasmid characteristics of Escherichia coli were determined with the aim of deducing how mcr genes may have spread on a colistin withdrawn pig farm. Whole genome hybrid sequencing was applied to six mcr-positive E. coli (MCRPE) strains isolated from pigs, a farmworker and wastewater collected between 2017 and 2019. Among these, mcr-1.1 genes were identified on IncI2 plasmids from a pig and wastewater, and on IncX4 from the human isolate, whereas mcr-3 genes were found on plasmids IncFII and IncHI2 in two porcine strains. The MCRPE isolates exhibited genotypic and phenotypic multidrug resistance (MDR) traits as well as heavy metal and antiseptic resistance genes. The mcr-1.1-IncI2 and IncX4 plasmids carried only colistin resistance genes. Whereas, the mcr-3.5-IncHI2 plasmid presented MDR region, with several mobile genetic elements. Despite the MCRPE strains belonged to different E. coli lineages, mcr-carrying plasmids with high similarities were found in isolates from pigs and wastewater recovered in different years. This study highlighted that several factors, including the resistomic profile of the host bacteria, co-selection via adjunct antibiotic resistance genes, antiseptics, and/or disinfectants, and plasmid-host fitness adaptation may encourage the maintenance of plasmids carrying mcr genes in E. coli.
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Affiliation(s)
- Nwai Oo Khine
- Center of Excellence in Diagnosis and Monitoring of Animal Pathogens (DMAP), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Thidathip Wongsurawat
- Division of Bioinformatics and Data Management for Research, Research Group and Research Network Division, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Piroon Jenjaroenpun
- Division of Bioinformatics and Data Management for Research, Research Group and Research Network Division, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - David J Hampson
- School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Nuvee Prapasarakul
- Center of Excellence in Diagnosis and Monitoring of Animal Pathogens (DMAP), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
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Sun J, Chen W, Yuan Z. Characterization of Intestinal Microbiota in Lambs with Different Susceptibility to Escherichia coli F17. Vet Sci 2022; 9:vetsci9120670. [PMID: 36548832 PMCID: PMC9782581 DOI: 10.3390/vetsci9120670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/14/2022] [Accepted: 11/29/2022] [Indexed: 12/04/2022] Open
Abstract
Diarrhea is one of the most commonly reported diseases in young farm animals. Escherichia coli (E. coli) F17 is one of the major pathogenic bacteria responsible for diarrhea. However, the pathogenicity of diarrhea in lambs involving E. coli F17 strains and how E. coli F17 infection modifies lambs' intestinal microbiota are largely unknown. To evaluate diarrhea in newborn lambs with an infection of E. coli F17, 50 lambs were selected for challenge experiments and divided into four groups, namely, a high-dose challenge group, low-dose challenge group, positive control group, and negative control group. The E. coli F17 challenge experiments caused diarrhea and increased mortality in the experimental lamb population, with a higher prevalence (90%), mortality (35%), and rapid onset time (4-12 h) being observed in the high-dose challenge group than the results observed in the low-dose challenge group (75%, 10%, 6-24 h, respectively). After the challenge experiment, healthy lambs in the high-dose challenge group and severely diarrheic lamb in the low-dose challenge group were identified as lambs sensitive/resistant to E. coli F17 (E. coli F17 -resistant/-sensitive candidate, AN/SE) according to the histopathological detection. Results of intestinal contents bacteria plate counting revealed that the number of bacteria in the intestinal contents of SE lambs was 102~3-fold greater than that of the AN lambs, especially in the jejunum. Then, 16S rRNA sequencing was conducted to profile the intestinal microbiota using the jejunal contents, and the results showed that SE lambs had higher Lactococcus and a lower Bacteroidetes:Firmicutes ratio and intestinal microbiota diversity in the jejunum than AN lambs. Notably, high abundance of Megasphaera elsdenii was revealed in AN lambs, which indicated that Megasphaera elsdenii may serve as a potential probiotic for E. coli F17 infection. Our study provides an alternative challenge model for the identification of E. coli F17-sensitive/-resistant lambs and contributes to the basic understandings of intestinal microbiota in lambs with different susceptibilities to E. coli F17.
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Affiliation(s)
- Jingyi Sun
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
| | - Weihao Chen
- College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Zehu Yuan
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
- International Joint Research Laboratory in Universities of Jiangsu Province of China for Domestic Animal Germplasm Resources and Genetic Improvement, Yangzhou University, Yangzhou 225009, China
- Correspondence:
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He WY, Zhang XX, Gao GL, Gao MY, Zhong FG, Lv LC, Cai ZP, Si XF, Yang J, Liu JH. Clonal spread of Escherichia coli O101: H9-ST10 and O101: H9-ST167 strains carrying fosA3 and bla CTX-M-14 among diarrheal calves in a Chinese farm, with Australian Chroicocephalus as the possible origin of E. coli O101: H9-ST10. Zool Res 2021; 42:461-468. [PMID: 34156173 PMCID: PMC8317193 DOI: 10.24272/j.issn.2095-8137.2021.153] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
During a 2018 antimicrobial resistance surveillance of Escherichia coli isolates from diarrheal calves in Xinjiang Province, China, an unexpectedly high prevalence (48.5%) of fosfomycin resistance was observed. This study aimed to reveal the determinants of fosfomycin resistance and the underlying transmission mechanism. Polymerase chain reaction (PCR) screening showed that all fosfomycin-resistant E. coli carried the fosA3 gene. Pulsed-field gel electrophoresis (PFGE) and southern blot hybridization revealed that the 16 fosA3-positive isolates belonged to four different PFGE patterns (i.e., A, B, C, D). The fosA3 genes of 11 clonally related strains (pattern D) were located on the chromosome, while others were carried by plasmids. Whole-genome and long-read sequencing indicated that the pattern D strains were E. coli O101:H9-ST10, and the pattern C, B, and A strains were O101:H9-ST167, O8:H30-ST1431, and O101:H9 with unknown ST, respectively. Among the pattern C strains, the blaCTX-M-14 gene was co-localized with the fosA3 gene on the F18:A-:B1 plasmids. Interestingly, phylogenetic analysis based on core genome single nucleotide polymorphisms (cgSNPs) showed that the O101:H9-ST10 strains were closely related to a Australian-isolated Chroicocephalus-origin E. coli O101:H9-ST10 strain producing CTX-M-14 and FosA3, with a difference of only 11 SNPs. These results indicate possible international dissemination of the high-risk E. coli clone O101:H9-ST10 by migratory birds.
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Affiliation(s)
- Wan-Yun He
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong 510642, China
| | - Xing-Xing Zhang
- State Key Laboratory for Sheep Genetic Improvement and Healthy Production, Institute of Animal Husbandry and Veterinary, Xinjiang Academy of Agricultural and Reclamation Science, Shihezi, Xinjiang, 832000, China
| | - Guo-Long Gao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong 510642, China
| | - Ming-Yi Gao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong 510642, China
| | - Fa-Gang Zhong
- State Key Laboratory for Sheep Genetic Improvement and Healthy Production, Institute of Animal Husbandry and Veterinary, Xinjiang Academy of Agricultural and Reclamation Science, Shihezi, Xinjiang, 832000, China
| | - Lu-Chao Lv
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong 510642, China
| | - Zhong-Peng Cai
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong 510642, China
| | - Xing-Feng Si
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Jun Yang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong 510642, China. E-mail:
| | - Jian-Hua Liu
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, Guangdong 510642, China. E-mail:
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Tang F, Wang J, Li D, Gao S, Ren J, Ma L, Liu F, Zhuge X, Yan G, Lu Y, Dai J. Comparative genomic analysis of 127 Escherichia coli strains isolated from domestic animals with diarrhea in China. BMC Genomics 2019; 20:212. [PMID: 30866824 PMCID: PMC6416869 DOI: 10.1186/s12864-019-5588-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 03/06/2019] [Indexed: 11/16/2022] Open
Abstract
Background Escherichia coli is an important pathogen that causes diarrhea in both humans and animals. To determine the relationships between putative virulence factors and pathotypes or host taxa, many molecular studies on diarrhea-associated E. coli have been reported. However, little is known regarding genome-wide variation of E. coli from animal hosts. In this study, we performed whole genome sequencing of 127 E. coli isolates from sheep and swine with diarrhea in China. We compared isolates to explore the phylogenomic relatedness based on host origin. We explored the relationships of putative virulence factors across host taxa and pathotypes. Antimicrobial resistance was also tested. Results The E. coli genomes in this study were diverse with clear differences in the SNP, MLST, and O serotypes. Seven putative virulence factors (VFs) were prevalent (> 95%) across the isolates, including Hcp, csgC, dsdA, feoB, fepA, guaA, and malX. Sixteen putative VFs showed significantly different distributions (P < 0.05) in strains from sheep and swine and were primarily adhesion- and toxin-related genes. Some putative VFs were co-occurrent in some specific pathotypes and O serotypes. The distribution of 4525 accessory genes of the 127 strains significantly differed (P < 0.05) between isolates obtained from the two animal species. The 127 animal isolates sequenced in this study were each classified into one of five pathotypes: EAEC, ETEC, STEC, DAEC, and EPEC, with 66.9% of isolates belonging to EAEC. Analysis of stx subtypes and a minimum spanning tree based on MLST revealed that STEC isolates from sheep and EAEC isolates from sheep and swine have low potential to infect humans. Antibiotic resistance analysis showed that the E. coli isolates were highly resistant to ampicillin and doxycycline. Isolates from southeast China were more resistant to antibiotics than isolates from northwest China. Additionally, the plasmid-mediated colist in resistance gene mcr-1 was detected in 15 isolates, including 4 from sheep in Qinghai and 11 from swine in Jiangsu. Conclusions Our study provides insight into the genomes of E. coli isolated from animal sources. Distinguishable differences between swine and sheep isolates at the genomic level provides a baseline for future investigations of animal E. coli pathogens. Electronic supplementary material The online version of this article (10.1186/s12864-019-5588-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fang Tang
- Key Lab Animal Bacteriology, Ministry of Agriculture; Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu Province, 210095, People's Republic of China
| | - Juanfang Wang
- Key Lab Animal Bacteriology, Ministry of Agriculture; Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu Province, 210095, People's Republic of China
| | - Dezhi Li
- Key Lab Animal Bacteriology, Ministry of Agriculture; Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu Province, 210095, People's Republic of China
| | - Song Gao
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, People's Republic of China
| | - Jianluan Ren
- Key Lab Animal Bacteriology, Ministry of Agriculture; Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu Province, 210095, People's Republic of China
| | - Liqing Ma
- Qinghai Academy of veterinary Medicine and Animal Science, Qinghai University, Xining, Qinghai Province, People's Republic of China
| | - Fei Liu
- CAS key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Xiangkai Zhuge
- Key Lab Animal Bacteriology, Ministry of Agriculture; Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu Province, 210095, People's Republic of China
| | - Genqiang Yan
- College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, People's Republic of China
| | - Yan Lu
- Qinghai Academy of veterinary Medicine and Animal Science, Qinghai University, Xining, Qinghai Province, People's Republic of China
| | - Jianjun Dai
- Key Lab Animal Bacteriology, Ministry of Agriculture; Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, No.1 Weigang, Nanjing, Jiangsu Province, 210095, People's Republic of China.
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Dubreuil JD, Isaacson RE, Schifferli DM. Animal Enterotoxigenic Escherichia coli. EcoSal Plus 2016; 7:10.1128/ecosalplus.ESP-0006-2016. [PMID: 27735786 PMCID: PMC5123703 DOI: 10.1128/ecosalplus.esp-0006-2016] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Indexed: 12/13/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is the most common cause of E. coli diarrhea in farm animals. ETEC are characterized by the ability to produce two types of virulence factors: adhesins that promote binding to specific enterocyte receptors for intestinal colonization and enterotoxins responsible for fluid secretion. The best-characterized adhesins are expressed in the context of fimbriae, such as the F4 (also designated K88), F5 (K99), F6 (987P), F17, and F18 fimbriae. Once established in the animal small intestine, ETEC produce enterotoxin(s) that lead to diarrhea. The enterotoxins belong to two major classes: heat-labile toxins that consist of one active and five binding subunits (LT), and heat-stable toxins that are small polypeptides (STa, STb, and EAST1). This review describes the disease and pathogenesis of animal ETEC, the corresponding virulence genes and protein products of these bacteria, their regulation and targets in animal hosts, as well as mechanisms of action. Furthermore, vaccines, inhibitors, probiotics, and the identification of potential new targets by genomics are presented in the context of animal ETEC.
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Affiliation(s)
- J Daniel Dubreuil
- Faculté de Médecine Vétérinaire, Université de Montréal, Québec J2S 7C6, Canada
| | - Richard E Isaacson
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN 55108
| | - Dieter M Schifferli
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104
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Abstract
The first described adhesive antigen of Escherichia coli strains isolated from animals was the K88 antigen, expressed by strains from diarrheic pigs. The K88 antigen was visible by electron microscopy as a surface-exposed filament that was thin and flexible and had hemagglutinating properties. Many different fimbriae have been identified in animal enterotoxigenic E. coli (ETEC) and have been discussed in this article. The role of these fimbriae in the pathogenesis of ETEC has been best studied with K88, K99, 987P, and F41. Each fimbrial type carries at least one adhesive moiety that is specific for a certain host receptor, determining host species, age, and tissue specificities. ETEC are the most frequently diagnosed pathogens among neonatal and post-weaning piglets that die of diarrhea. Immune electron microscopy of animal ETEC fimbriae usually shows that the minor subunits are located at the fimbrial tips and at discrete sites along the fimbrial threads. Since fimbriae most frequently act like lectins by binding to the carbohydrate moieties of glycoproteins or glycolipids, fimbrial receptors have frequently been studied with red blood cells of various animal species. Identification and characterization of the binding moieties of ETEC fimbrial adhesins should be useful for the design of new prophylactic or therapeutic strategies. Some studies describing potential receptor or adhesin analogues that interfere with fimbria-mediated colonization have been described in the article.
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Discovery and phylogenetic analysis of novel members of class b enterotoxigenic Escherichia coli adhesive fimbriae. J Clin Microbiol 2011; 49:1403-10. [PMID: 21289147 DOI: 10.1128/jcm.02006-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is recognized to be a common cause of acute watery diarrhea in children from developing countries. Colonization factors (CFAs) have been identified predominantly in ETEC isolates secreting heat-stable enterotoxin (ST) or cosecreting ST with a heat-labile toxin (LT). We hypothesized that LT-only-secreting ETEC produces unique colonization factors not previously described in ST and LTST-secreting ETEC. A set of degenerate primers based on nucleotide sequence similarities between the major structural genes of CS20 (csnA), CS18 (fotA), CS12 (cswA), and porcine antigen 987 (fasA) was developed and used to screen a collection of 266 LT-secreting ETEC isolates in which no known CFA was detected. PCR-amplified products of different molecular masses were obtained from 49 (18.4%) isolates. Nucleotide sequence analysis of the PCR amplicons followed by GenBank nucleotide BLASTn analysis revealed five novel DNA sequences; translated amino acid BLASTx analysis confirmed sequence similarity to class 1b major structural proteins encoded by csnA, fotA, and fasA. Strains expressing the novel CFAs were phylotyped and analyzed using multilocus sequence typing (MLST; Achtman scheme), and the types detected were compared to those of a collection of archived global E. coli strains. In conclusion, application of the degenerate primer sets to ETEC isolates from surveillance studies increased the total number of ETEC isolates with detectable CFAs by almost 20%. Additionally, MLST analysis suggests that for many CFAs, there may be a requirement for certain genetic backgrounds to acquire and maintain plasmids carrying genes encoding CFAs.
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Güler L, Gündüz K, Ok Ü. Virulence Factors and Antimicrobial Susceptibility of Escherichia coli Isolated from Calves in Turkey. Zoonoses Public Health 2008; 55:249-57. [DOI: 10.1111/j.1863-2378.2008.01121.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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10
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Abstract
Enterotoxigenic Escherichia coli (ETEC) infection is the most common type of colibacillosis of young animals (primarily pigs and calves), and it is a significant cause of diarrhoea among travellers and children in the developing world. The main virulence attributes of ETEC are adhesins and enterotoxins, which are mostly regulated on large plasmids. Almost all ETEC bacteria are known to adhere to receptors on the small intestinal epithelium by their proteinaceous surface appendages (fimbriae, pili) or by afimbrial proteins without inducing significant morphological changes. Furthermore, they secrete protein toxins (enterotoxins) to reduce absorption and to increase fluid and electrolyte secretion of small intestinal epithelial cells. Regarding details of epidemiology, pathogenesis, diagnosis and prevention of ETEC infections and diarrhoea in animals, readers are referred to an earlier more extensive review [Nagy and Fekete, 1999. Enterotoxigenic Escherichia coli (ETEC) in farm animals. Vet. Res. 30, 259-284]. This paper intends to summarise our basic knowledge and to highlight the new developments and most actual research topics in the area of ETEC infections in veterinary medicine. Attention is paid to recently described new virulence factors and to new genetic vectors in ETEC bacteria. Applications of our knowledge in the diagnosis and prevention of ETEC diarrhoea in animals will also be discussed.
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Affiliation(s)
- Béla Nagy
- Veterinary Medical Research Institute of the Hungarian Academy of Sciences, Hungária krt. 21, H-1143 Budapest, Hungary.
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Kern WV, Klose K, Jellen-Ritter AS, Oethinger M, Bohnert J, Kern P, Reuter S, von Baum H, Marre R. Fluoroquinolone resistance of Escherichia coli at a cancer center: epidemiologic evolution and effects of discontinuing prophylactic fluoroquinolone use in neutropenic patients with leukemia. Eur J Clin Microbiol Infect Dis 2005; 24:111-8. [PMID: 15714332 DOI: 10.1007/s10096-005-1278-x] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aim of the present study was to investigate the epidemiologic evolution of fluoroquinolone resistance of E. coli clinical isolates from patients admitted to a hematology-oncology service where fluoroquinolone prophylaxis during neutropenia was recommended as the standard of care for many years but was then discontinued in a trial conducted in patients with acute leukemia. Fluoroquinolones had been shown to decrease the incidence of gram-negative bacteremia in cancer patients with neutropenia, yet it was thought that the emergence of resistance in Escherichia coli and other gram-negative bacteria may have caused a progressive lack of efficacy of fluoroquinolone prophylaxis. Epidemiologic surveillance of fluoroquinolone resistance of E. coli clinical isolates at our cancer center since 1992 showed a continuing influx of new clones not previously observed in the population of cancer patients, an increase in the number of cancer patients per year colonized and/or infected by fluoroquinolone-resistant E. coli (1992-1994, 10-16 patients; 1995-1997, 24-27 patients), and a resistance rate of >50% among E. coli bloodstream isolates of hematology-oncology patients. A 6-month fluoroquinolone prophylaxis discontinuation intervention trial in 1998 suggested that despite increasing resistance among E. coli isolates, fluoroquinolone prophylaxis in acute leukemia patients was still effective in the prevention of gram-negative bacteremia (incidence rates, 8% during the pre-intervention period vs. 20% after discontinuation; p<0.01). The resumption of fluoroquinolone prophylaxis in acute leukemia patients thereafter decreased the incidence of gram-negative bacteremia to the pre-intervention level (9%; p=0.03), while the proportion of in vitro fluoroquinolone resistance in E. coli bacteremia isolates again increased (from 15% during the intervention period to >50% in the post-intervention period). Relative rates of resistance thus were a poor indicator of the potential clinical benefits associated with fluoroquinolone prophylaxis in cancer patients.
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Affiliation(s)
- W V Kern
- Center for Infectious Diseases and Travel Medicine, Department of Medicine, University Hospital, Hugstetter Strasse 55, 79106 Freiburg, Germany.
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