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Jarquin C, Morales O, McCracken JP, Lopez MR, Lopez B, Reyes L, Gómez GA, Bryan JP, Peruski LF, Pattabiraman V, Parsons MB. Burden of Diarrheagenic
Escherichia coli
in Santa Rosa, Guatemala in active health‐services surveillance during 2008‐2009 and 2014‐2015. Trop Med Int Health 2022; 27:408-417. [DOI: 10.1111/tmi.13735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Claudia Jarquin
- Center for Health Studies Universidad del Valle de Guatemala Guatemala City Guatemala
| | - Oneida Morales
- Center for Health Studies Universidad del Valle de Guatemala Guatemala City Guatemala
| | - John P. McCracken
- Center for Health Studies Universidad del Valle de Guatemala Guatemala City Guatemala
| | - Maria R. Lopez
- Center for Health Studies Universidad del Valle de Guatemala Guatemala City Guatemala
| | - Beatriz Lopez
- US Centers for Disease Control and Prevention Central America Regional Office Center for Global Health Guatemala
| | - Lisette Reyes
- Guatemalan Ministry of Public Health and Social Welfare Guatemala
| | - Gerardo A. Gómez
- National Center for Emerging and Zoonotic Infectious Diseases US Centers for Disease Control and Prevention Atlanta USA
| | - Joe P. Bryan
- US Centers for Disease Control and Prevention Central America Regional Office Center for Global Health Guatemala
| | - Leonard F. Peruski
- US Centers for Disease Control and Prevention Central America Regional Office Center for Global Health Guatemala
| | - Vaishnavi Pattabiraman
- National Center for Emerging and Zoonotic Infectious Diseases US Centers for Disease Control and Prevention Atlanta USA
| | - Michele B. Parsons
- National Center for Emerging and Zoonotic Infectious Diseases US Centers for Disease Control and Prevention Atlanta USA
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Jarocki VM, Heß S, Anantanawat K, Berendonk TU, Djordjevic SP. Multidrug-Resistant Lineage of Enterotoxigenic Escherichia coli ST182 With Serotype O169:H41 in Airline Waste. Front Microbiol 2021; 12:731050. [PMID: 34557175 PMCID: PMC8454413 DOI: 10.3389/fmicb.2021.731050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 07/21/2021] [Indexed: 12/30/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is the primary aetiologic agent of traveller’s diarrhoea and a significant cause of diarrhoeal disease and death in developing countries. ETEC O169:H41 strains are known to cause both traveller’s diarrhoea and foodborne outbreaks in developed countries and are cause for concern. Here, whole-genome sequencing (WGS) was used to assemble 46 O169:H41 (ST182) E. coli draft genomes derived from two airplane waste samples sourced from a German international airport. The ST182 genomes were compared with all 84 publicly available, geographically diverse ST182 genomes to construct a core genome-based phylogenetic tree. ST182 isolates were all phylogroup E, the majority serotype O169:H41 (n = 121, 93%) and formed five major clades. The airplane waste isolates differed by an average of 15 core SNPs (range 0–45) but their accessory genome content was diverse. While uncommon in other ST182 genomes, all airplane-derived ST182 isolates carried: (i) extended-spectrum β-lactamase gene blaCTX–M–15 notably lacking the typical adjacent ISEcp1; (ii) qnrS1 and the S83L mutation in gyrA, both conferring resistance to fluoroquinolones; and (iii) a class 1 integron structure (IS26-intI1Δ648-dfrA17-aadA5-qacEΔ1-sul1-ORF-srpC-padR-IS6100-mphR-mrx-mphA-IS26) identified previously in major extraintestinal pathogenic E. coli STs but not in ETEC. ST182 isolates carried ETEC-specific virulence factors STp + CS6. Adhesin/invasin tia was identified in 89% of aircraft ST182 isolates (vs 23%) and was located on a putative genomic island within a hotspot region for various insertions including PAI I536 and plasmid-associated transposons. The most common plasmid replicons in this collection were IncFII (100%; F2:A-:B-) and IncB/O/K/Z (89%). Our data suggest that potentially through travel, E. coli ST182 are evolving a multidrug-resistant profile through the acquisition of class 1 integrons and different plasmids.
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Affiliation(s)
- Veronica M Jarocki
- iThree Institute, University of Technology Sydney, Sydney, NSW, Australia
| | - Stefanie Heß
- Institute of Microbiology, Technische Universität Dresden, Dresden, Germany
| | - Kay Anantanawat
- iThree Institute, University of Technology Sydney, Sydney, NSW, Australia
| | - Thomas U Berendonk
- Institute of Hydrobiology, Technische Universität Dresden, Dresden, Germany
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Li Y, Luo Q, Shi X, Lin Y, Qiu Y, Lv D, Jiang Y, Chen Q, Jiang M, Ma H, Cheng J, Hu Q. Phenotypic and Genotypic Characterization of Clinical Enterotoxigenic Escherichia coli Isolates from Shenzhen, China. Foodborne Pathog Dis 2017; 14:333-340. [DOI: 10.1089/fpd.2016.2233] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Yinghui Li
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Qiang Luo
- College of Life Sciences, Sichuan University, Chengdu, China
| | - Xiaolu Shi
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Yiman Lin
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Yaqun Qiu
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Dongyue Lv
- School of Life Sciences, Shenzhen University, Shenzhen, China
| | - Yixiang Jiang
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Qiongcheng Chen
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Min Jiang
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Hanwu Ma
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Jinquan Cheng
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Qinghua Hu
- Shenzhen Center for Disease Control and Prevention, Shenzhen, China
- School of Life Sciences, Shenzhen University, Shenzhen, China
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Joffré E, von Mentzer A, Svennerholm AM, Sjöling Å. Identification of new heat-stable (STa) enterotoxin allele variants produced by human enterotoxigenic Escherichia coli (ETEC). Int J Med Microbiol 2016; 306:586-594. [PMID: 27350142 DOI: 10.1016/j.ijmm.2016.05.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 05/25/2016] [Accepted: 05/25/2016] [Indexed: 11/16/2022] Open
Abstract
We describe natural variants of the heat stable toxin (STa) produced by enterotoxigenic Escherichia coli (ETEC) isolates collected worldwide. Previous studies of ETEC isolated from human diarrheal cases have reported the existence of three natural STa gene variants estA1, estA2 and estA3/4 where the first variant encodes STp (porcine, bovine, and human origin) and the two latter ones encode STh (human origin). We identified STa sequences by BLASTn and profiled ST amino acid polymorphisms in a collection of 118 clinical ETEC isolates from children and adults from Asia, Africa and, Latin America that were characterized by whole genome sequencing. Three novel variants of STp and STh were found and designated STa5 and STa6, and STa7, respectively. Presence of glucose significantly decreased the production of STh and STp toxin variants (p<0.05) as well as downregulated the gene expression (STh: p<0.001, STp: p<0.05). We found that the ETEC isolates producing the most common STp variant, STa5, co-expressed coli surface antigen CS6 and was significantly associated with disease in adults in this data set (p<0.001). Expression of mature STa5 peptide as well as gene expression of tolC, involved in ST secretion, increased in response to bile (p<0.05). ETEC expressing the common STh variant STa3/4 was associated with disease in children (p<0.05). The crp gene, that positively regulate estA3/4 encoding STa3/4, and estA3/4 itself had decreased transcriptional levels in presence of bile. Since bile levels in the intestine are lower in children than adults, these results may suggest differences in pathogenicity of ETEC in children and adult populations.
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Affiliation(s)
- Enrique Joffré
- Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Institute of Molecular Biology and Biotechnology, Universidad Mayor de San Andrés, La Paz, Bolivia.
| | - Astrid von Mentzer
- Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; The Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Ann-Mari Svennerholm
- Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Åsa Sjöling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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Joffré E, Sjöling Å. The LT1 and LT2 variants of the enterotoxigenic Escherichia coli (ETEC) heat-labile toxin (LT) are associated with major ETEC lineages. Gut Microbes 2016; 7:75-81. [PMID: 26939855 PMCID: PMC4856455 DOI: 10.1080/19490976.2015.1127480] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The heat-labile toxin (LT) is one of the major virulence factors of enterotoxigenic Escherichia coli (ETEC). We recently described that 20 polymorphic LT variants are present in ETEC strains isolated globally. Two of the variants, LT1 and LT2, are particularly common and we found that they were associated with clonal ETEC lineages that express the colonization factors (CFs), CFA/I, CS1+CS3, CS2+CS3, and CS5+CS6. ETEC expressing these CFs are frequently found among ETEC strains isolated from cases with diarrhea. ETEC expressing the colonization factors CS1+CS3, and CS2+CS3 are found in 2 discrete clonal lineages and express the LT1 variant and heat stable toxin (STh). Although they clearly are virulent they neither produce, nor secrete, high amounts of LT toxin. On the other hand ETEC strains expressing LT, STh, CFA/I and LT, STh, CS5+CS6, carry the LT2 variant and produce and secrete significantly more LT toxin. Despite differences in toxin production, LT1 and LT2 are found in ETEC lineages that have managed to spread globally confirming that these variants are important for ETEC virulence.
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Affiliation(s)
- Enrique Joffré
- Department of Microbiology and Immunology; Sahlgrenska Academy; University of Gothenburg; Göteborg, Sweden,Institute of Molecular Biology and Biotechnology; Universidad Mayor de San Andrés; La Paz, Bolivia,Department of Microbiology; Tumor and Cell Biology; Karolinska Institutet; Stockholm, Sweden
| | - Åsa Sjöling
- Department of Microbiology; Tumor and Cell Biology; Karolinska Institutet; Stockholm, Sweden
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Toxins and virulence factors of enterotoxigenic Escherichia coli associated with strains isolated from indigenous children and international visitors to a rural community in Guatemala. Epidemiol Infect 2014; 143:1662-71. [PMID: 25233938 PMCID: PMC4416357 DOI: 10.1017/s0950268814002295] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Diarrhoea remains a common cause of illness in Guatemala, with children suffering most frequently from the disease. This study directly compared the frequency, enterotoxin, and colonization factor (CF) profiles of enterotoxigenic Escherichia coli (ETEC) strains isolated from children living in a rural community in Guatemala and from Western visitors to the same location during the same seasons, using similar detection methodologies. We found that ETEC accounted for 26% of severe cases of diarrhoea in children requiring hospitalization, 15% of diarrhoea in the community, and 29% of travellers' diarrhoea in visitors staying ⩾2 weeks. The toxin and CF patterns of the ETEC strains isolated from both groups differed significantly (P < 0·0005) as determined by χ2 = 60·39 for CFs and χ2 = 35 for toxins, while ETEC phenotypes found in Guatemalan children were comparable to those found in children from other areas of the world.
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Oh KH, Kim DW, Jung SM, Cho SH. Molecular characterization of Enterotoxigenic Escherichia coli strains isolated from diarrheal patients in Korea during 2003-2011. PLoS One 2014; 9:e96896. [PMID: 24841334 PMCID: PMC4026316 DOI: 10.1371/journal.pone.0096896] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 04/12/2014] [Indexed: 11/18/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is one of the major causes of infectious diarrhea in developing countries. In order to characterize the molecular features of human ETEC isolates from Korea, we investigated the profiles of enterotoxin and colonization factor (CF) genes by polymerase chain reaction (PCR) and performed multilocus sequence typing (MLST) with a total of 291 ETEC strains. The specimens comprised 258 domestic strains isolated from patients who had diarrhea and were from widely separated geographic regions in Korea and 33 inflow strains isolated from travelers visiting other Asian countries. Heat-stable toxin (STh)-possessing ETEC strains were more frequent than heat-labile toxin (LT)-possessing ETEC strains in the domestic isolates, while the detection rates of both enterotoxin genes were similar in the inflow isolates. The profile of CF genes of domestic isolates was similar to that of inflow isolates and the major CF types of the strains were CS3-CS21-CS1/PCF071 and CS2-CS3-CS21. Most of these 2 CF types were detected in ETEC strains that possess both lt and sth genes. The major MLSTST types of domestic isolates were ST171 and ST955. Moreover, the 2 major CF types were usually found concomitantly with the 2 major MLST STs, ST171 and ST955. In conclusion, our genotyping results may provide useful information for guiding the development of geographically specific vaccines against human ETEC isolates.
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Affiliation(s)
- Kyung-Hwan Oh
- Division of Enteric Bacterial Infections, Center for Infectious Diseases, Korea National Institute of Health, Osong-eup, Chungcheongbuk-do, Republic of Korea
| | - Dong Wook Kim
- Department of Pharmacy, College of Pharmacy, Hanyang University, Ansan, Kyeonggi-do, Republic of Korea
| | - Su-Mi Jung
- Division of Enteric Bacterial Infections, Center for Infectious Diseases, Korea National Institute of Health, Osong-eup, Chungcheongbuk-do, Republic of Korea
| | - Seung-Hak Cho
- Division of Enteric Bacterial Infections, Center for Infectious Diseases, Korea National Institute of Health, Osong-eup, Chungcheongbuk-do, Republic of Korea
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Phenotypic and genotypic characterization of enterotoxigenic Escherichia coli clinical isolates from northern Colombia, South America. BIOMED RESEARCH INTERNATIONAL 2014; 2014:236260. [PMID: 24877071 PMCID: PMC4022111 DOI: 10.1155/2014/236260] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/07/2014] [Accepted: 04/08/2014] [Indexed: 12/13/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) are major causes of childhood diarrhea in low and middle income countries including Colombia, South America. To understand the diversity of ETEC strains in the region, clinical isolates obtained from northern Colombia children were evaluated for multiple locus sequencing typing, serotyping, classical and nonclassical virulence genes, and antibiotic susceptibility. Among 40 ETEC clinical isolates evaluated, 21 (52.5%) were positive for LT gene, 13 (32.5%) for ST gene, and 6 (15%) for both ST and LT. The most prevalent colonization surface antigens (CS) were CS21 and CFA/I identified in 21 (50%) and 13 (32.5%) isolates, respectively. The eatA, irp2, and fyuA were the most common nonclassical virulence genes present in more than 60% of the isolates. Ampicillin resistance (80% of the strains) was the most frequent phenotype among ETEC strains followed by trimethoprim-sulfamethoxazole resistance (52.5%). Based on multiple locus sequencing typing (MLST), we recognize that 6 clonal groups of ETEC clinical isolates circulate in Colombia. ETEC clinical isolates from children in northern Colombia are highly diverse, yet some isolates circulating in the community belong to well-defined clonal groups that share a unique set of virulence factors, serotypes, and MLST sequence types.
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González-González A, Sánchez-Reyes LL, Delgado Sapien G, Eguiarte LE, Souza V. Hierarchical clustering of genetic diversity associated to different levels of mutation and recombination in Escherichia coli: a study based on Mexican isolates. INFECTION GENETICS AND EVOLUTION 2012; 13:187-97. [PMID: 22995280 DOI: 10.1016/j.meegid.2012.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 02/01/2023]
Abstract
Escherichia coli occur as either free-living microorganisms, or within the colons of mammals and birds as pathogenic or commensal bacteria. Although the Mexican population of intestinal E. coli maintains high levels of genetic diversity, the exact mechanisms by which this occurs remain unknown. We therefore investigated the role of homologous recombination and point mutation in the genetic diversification and population structure of Mexican strains of E. coli. This was explored using a multi locus sequence typing (MLST) approach in a non-outbreak related, host-wide sample of 128 isolates. Overall, genetic diversification in this sample appears to be driven primarily by homologous recombination, and to a lesser extent, by point mutation. Since genetic diversity is hierarchically organized according to the MLST genealogy, we observed that there is not a homogeneous recombination rate, but that different rates emerge at different clustering levels such as phylogenetic group, lineage and clonal complex (CC). Moreover, we detected clear signature of substructure among the A+B1 phylogenetic group, where the majority of isolates were differentiated into four discrete lineages. Substructure pattern is revealed by the presence of several CCs associated to a particular life style and host as well as to different genetic diversification mechanisms. We propose these findings as an alternative explanation for the maintenance of the clear phylogenetic signal of this species despite the prevalence of homologous recombination. Finally, we corroborate using both phylogenetic and genetic population approaches as an effective mean to establish epidemiological surveillance tailored to the ecological specificities of each geographic region.
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Affiliation(s)
- Andrea González-González
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, México D.F., Mexico
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Rodas C, Klena JD, Nicklasson M, Iniguez V, Sjöling Å. Clonal relatedness of enterotoxigenic Escherichia coli (ETEC) strains expressing LT and CS17 isolated from children with diarrhoea in La Paz, Bolivia. PLoS One 2011; 6:e18313. [PMID: 22140423 PMCID: PMC3226562 DOI: 10.1371/journal.pone.0018313] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 03/03/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Enterotoxigenic Escherichia coli (ETEC) is a major cause of traveller's and infantile diarrhoea in the developing world. ETEC produces two toxins, a heat-stable toxin (known as ST) and a heat-labile toxin (LT) and colonization factors that help the bacteria to attach to epithelial cells. METHODOLOGY/PRINCIPAL FINDINGS In this study, we characterized a subset of ETEC clinical isolates recovered from Bolivian children under 5 years of age using a combination of multilocus sequence typing (MLST) analysis, virulence typing, serotyping and antimicrobial resistance test patterns in order to determine the genetic background of ETEC strains circulating in Bolivia. We found that strains expressing the heat-labile (LT) enterotoxin and colonization factor CS17 were common and belonged to several MLST sequence types but mainly to sequence type-423 and sequence type-443 (Achtman scheme). To further study the LT/CS17 strains we analysed the nucleotide sequence of the CS17 operon and compared the structure to LT/CS17 ETEC isolates from Bangladesh. Sequence analysis confirmed that all sequence type-423 strains from Bolivia had a single nucleotide polymorphism; SNP(bol) in the CS17 operon that was also found in some other MLST sequence types from Bolivia but not in strains recovered from Bangladeshi children. The dominant ETEC clone in Bolivia (sequence type-423/SNP(bol)) was found to persist over multiple years and was associated with severe diarrhoea but these strains were variable with respect to antimicrobial resistance patterns. CONCLUSION/SIGNIFICANCE The results showed that although the LT/CS17 phenotype is common among ETEC strains in Bolivia, multiple clones, as determined by unique MLST sequence types, populate this phenotype. Our data also appear to suggest that acquisition and loss of antimicrobial resistance in LT-expressing CS17 ETEC clones is more dynamic than acquisition or loss of virulence factors.
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Affiliation(s)
- Claudia Rodas
- WHO Collaborating Centre for Research on Enterotoxigenic Escherichia coli (ETEC) and Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
- Instituto de Biología Molecular y Biotecnología, Universidad Mayor de San Andrés, Facultad de Ciencias Puras y Naturales, La Paz, Bolivia
| | - John D. Klena
- U.S. Naval Medical Research Unit-3, Clinical Trials and Military Studies Program, Cairo, Egypt
| | - Matilda Nicklasson
- WHO Collaborating Centre for Research on Enterotoxigenic Escherichia coli (ETEC) and Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Volga Iniguez
- Instituto de Biología Molecular y Biotecnología, Universidad Mayor de San Andrés, Facultad de Ciencias Puras y Naturales, La Paz, Bolivia
| | - Åsa Sjöling
- WHO Collaborating Centre for Research on Enterotoxigenic Escherichia coli (ETEC) and Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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Potential pathogenicity and host range of extended-spectrum beta-lactamase-producing Escherichia coli isolates from healthy poultry. Appl Environ Microbiol 2011; 77:5830-3. [PMID: 21705531 DOI: 10.1128/aem.02890-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Thirty of 33 epidemiologically unrelated extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates from healthy poultry lacked the virulence genes commonly associated with human-pathogenic strains. The main zoonotic risk is associated with the broad host range of avian E. coli belonging to sequence type complex 10 and of IncN and IncI1 plasmids carrying bla(CTX-M) or bla(SHV).
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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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