Prevalence, Virulence Gene Profiling, and Characterization of Enteroaggregative Escherichia coli from Children with Acute Diarrhea, Asymptomatic Nourished, and Malnourished Children Younger Than 5 Years of Age in India

Introduction: Enteropathogenic Escherichia coli (EPEC) causes infectious diarrhea among children in developing countries. However, in Nigeria, due to limited laboratory resources, the genetic diversity of its virulence factors, which include intimin subtypes, remains undefined. Methodology: EPEC isolates from diarrheic children 60 months of age and younger in Abuja, Nigeria, were analyzed. Polymerase chain reaction (PCR) for EPEC virulence gene, Hep-2 cell adherence, and serotyping were performed. EPEC strains were further subtyped by PCR for the identification of intimin subtype genes α (alpha), β (beta), γ1 (gamma-1), and έ (epsilon). Antibiotic resistance and extended-spectrum beta-lactamase (ESBL) production was determined by Clinical and Laboratory Standards Institute guidelines. Results: Overall, 18 (4.5%) out of 400 children with acute diarrhea had EPEC infection. Typical EPEC (tEPEC) strains were detected in 14 (3.5%), whereas 4 (1.1%) were atypical EPEC (aEPEC). A total of 15 (83.3%) of the EPEC isolated belonged to β intimin subtype gene, while the remaining 3 EPEC isolates possessed the intimin έ subtype. No α and γ intimin subtypes were detected. Traditional EPEC serotypes O114:H14 were detected only in tEPEC strains. Marked resistance to β-lactam agents were observed but no ESBL-producing tEPEC or aEPEC was detected. Conclusions: This is the first report of intimin subtype genes in Abuja, Nigeria. EPEC isolates of diverse serotypes resistant to β-lactam antimicrobial agents were observed. These data will be useful in facilitating the characterization of intimin variants of EPEC and some Shiga toxin-producing E. coli (STEC) in humans and other animal species.

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Molecular Characterization of Plasmid-Mediated Non-O157 Verotoxigenic Escherichia coli Isolated from Infants and Children with Diarrhea

Baghdad Science Journal ◽

10.21123/bsj.2020.17.3.0710 ◽

2020 ◽

Vol 17 (3) ◽

pp. 0710

Author(s):

Md Fazlul Karim Khan ◽

Shah Samiur Rashid

Keyword(s):

Escherichia Coli ◽

Virulence Gene ◽

Multidrug Resistant ◽

Plasmid Curing ◽

Health Issues ◽

E Coli ◽

Disk Diffusion Assay ◽

Microbiological Techniques ◽

Polymerase Chain

A significant increase in the incidence of non-O157 verotoxigenic Escherichia coli (VTEC) infections have become a serious health issues, and this situation is worsening due to the dissemination of plasmid mediated multidrug-resistant microorganisms worldwide. This study aims to investigate the presence of plasmid-mediated verotoxin gene in non-O157 E. coli. Standard microbiological techniques identified a total of 137 E. coli isolates. The plasmid was detected by Perfectprep Plasmid Mini preparation kit. These isolates were subjected to disk diffusion assay, and plasmid curing with ethidium bromide treatment. The plasmid containing isolates were subjected to a polymerase chain reaction (PCR) for investigating the presence of plasmid mediated verotoxin gene (VT1 and VT2) in non-O157 E. coli. Among the 137 E. coli isolates, 49 isolates were non-O157 E. coli while 29 (59.1%) isolates were verotoxin producing non-O157 serotypes and 26 non-O157 VTEC isolates possessed plasmids. Certain isolates harboured single sized plasmid while others had multiple plasmids with different size varied from 1.8kb to 7.6kb. A plasmid containing all (100%) the isolates was multidrug-resistant. Eight isolates changed their susceptibility patterns while three isolates were found to lose plasmid after post plasmid curing treatment and the rest of the isolates (15) remained constant. Different PCR sets characterized 3 plasmid-mediated verotoxins producing non-O157 E. coli. This current study demonstrated the occurrence of plasmid mediated verotoxin gene in non-O157 E. coli. To the best of our knowledge, this is the first report in the global literature on plasmid-mediated verotoxin gene in non-O157 E. coli. Timely diagnosis and surveillance of VTEC infections should prioritize to stop or slow down the virulence gene for dissemination by plasmid-mediated gene transfer amongst the same bacteria or other species.

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Extended-spectrum β-lactamase prevalence and virulence factor characterization of enterotoxigenic Escherichia coli responsible for acute diarrhea in Nepal from 2001 to 2016

Antimicrobial Resistance and Infection Control ◽

10.1186/s13756-018-0377-2 ◽

2018 ◽

Vol 7 (1) ◽

Cited By ~ 5

Author(s):

Katie R. Margulieux ◽

Apichai Srijan ◽

Sirigade Ruekit ◽

Panida Nobthai ◽

Kamonporn Poramathikul ◽

...

Keyword(s):

Escherichia Coli ◽

Virulence Factor ◽

Acute Diarrhea ◽

Enterotoxigenic Escherichia Coli ◽

Extended Spectrum

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Characteristics of Emerging Human-Pathogenic Escherichia coli O26:H11 Strains Isolated in France between 2010 and 2013 and Carrying thestx2dGene Only

Journal of Clinical Microbiology ◽

10.1128/jcm.02290-14 ◽

2014 ◽

Vol 53 (2) ◽

pp. 486-492 ◽

Cited By ~ 35

Author(s):

Sabine Delannoy ◽

Patricia Mariani-Kurkdjian ◽

Stephane Bonacorsi ◽

Sandrine Liguori ◽

Patrick Fach

Keyword(s):

Escherichia Coli ◽

Virulence Gene ◽

Gene Profiling ◽

Content Type ◽

E Coli ◽

Negative Results ◽

Pathogenic Escherichia Coli ◽

Short Palindromic Repeat ◽

Uremic Syndrome ◽

First Time

Strains ofEscherichia coliO26:H11 that were positive forstx2alone (n= 23), which were not epidemiologically related or part of an outbreak, were isolated from pediatric patients in France between 2010 and 2013. We were interested in comparing these strains with the new highly virulentstx2a-positiveE. coliO26 clone sequence type 29 (ST29) that has emerged recently in Europe, and we tested them by multilocus sequence typing (MLST),stx2subtyping, clustered regularly interspaced short palindromic repeat (CRISPR) sequencing, and plasmid (ehxA,katP,espP, andetpD) and chromosomal (Z2098,espK, andespV) virulence gene profiling. We showed that 16 of the 23 strains appeared to correspond to this new clone, but the characteristics of 12 strains differed significantly from the previously described characteristics, with negative results for both plasmid and chromosomal genetic markers. These 12 strains exhibited a ST29 genotype and related CRISPR arrays (CRISPR2a alleles 67 or 71), suggesting that they evolved in a common environment. This finding was corroborated by the presence ofstx2din 7 of the 12 ST29 strains. This is the first time thatE. coliO26:H11 carryingstx2dhas been isolated from humans. This is additional evidence of the continuing evolution of virulent Shiga toxin-producingE. coli(STEC) O26 strains. A new O26:H11 CRISPR PCR assay, SP_O26_E, has been developed for detection of these 12 particular ST29 strains ofE. coliO26:H11. This test is useful to better characterize thestx2-positive O26:H11 clinical isolates, which are associated with severe clinical outcomes such as bloody diarrhea and hemolytic uremic syndrome.

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Whole Genome Sequencing Characterization of Shiga Toxin–Producing Escherichia coli Isolated from Flour from Swiss Retail Markets

Journal of Food Protection ◽

10.4315/0362-028x.jfp-18-593 ◽

2019 ◽

Vol 82 (8) ◽

pp. 1398-1404 ◽

Cited By ~ 2

Author(s):

RENATE BOSS ◽

JOERG HUMMERJOHANN

Keyword(s):

Escherichia Coli ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Shiga Toxin ◽

Severe Disease ◽

Virulence Gene ◽

Whole Genome ◽

N 93 ◽

Human Infections

ABSTRACT Shiga toxin–producing Escherichia coli (STEC) strains are often found in food and cause human infections. Although STEC O157:H7 is most often responsible for human disease, various non-O157 subtypes have caused individual human infections or outbreaks. The importance of STEC serogroup typing is decreasing while detection of virulence gene patterns has become more relevant. Whole genome sequencing (WGS) reveals the entire spectrum of pathogen information, such as toxin variant, serotype, sequence type, and virulence factors. Flour has not been considered as a vector for STEC; however, this product has been associated with several STEC outbreaks in the last decade. Flour is a natural product, and milling does not include a germ-reducing step. Flour is rarely eaten raw, but the risks associated with the consumption of unbaked dough are probably underestimated. The aim of this study was to determine the prevalence of STEC in flour samples (n = 93) collected from Swiss markets and to fully characterize the isolates by PCR assay and WGS. The prevalence of STEC in these flour samples was 10.8% as indicated by PCR, and a total of 10 STEC strains were isolated (two flour samples were positive for two STEC subtypes). We found one stx2-positve STEC isolate belonging to the classic serogroups frequently associated with outbreaks that could potentially cause severe disease. However, we also found several other common or less common STEC subtypes with diverse virulence patterns. Our results reveal the benefits of WGS as a characterization tool and that flour is a potentially and probably underestimated source for STEC infections in humans.

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Molecular Characterization of a Serotype O121:H19 Clone, a Distinct Shiga Toxin-Producing Clone of Pathogenic Escherichia coli

Infection and Immunity ◽

10.1128/iai.70.12.6853-6859.2002 ◽

2002 ◽

Vol 70 (12) ◽

pp. 6853-6859 ◽

Cited By ~ 52

Author(s):

Cheryl L. Tarr ◽

Teresa M. Large ◽

Chris L. Moeller ◽

David W. Lacher ◽

Phillip I. Tarr ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Allelic Variation ◽

Virulence Gene ◽

Gene Profiling ◽

Enzyme Electrophoresis ◽

Sequencing Analysis ◽

Chromosomal Dna ◽

Waterborne Outbreak ◽

E Coli

ABSTRACT Most illnesses caused by Shiga toxin-producing Escherichia coli (STEC) have been attributed to E. coli serotype O157:H7, but non-O157 STEC infections are now increasingly recognized as public health problems worldwide. The O121:H19 serotype is being isolated more frequently from clinical specimens and has been implicated in one waterborne outbreak. We used multilocus virulence gene profiling, a PCR-based assay, to characterize the virulence gene content of 24 isolates of serotype O121:H19 and nonmotile variants. We also performed multilocus enzyme electrophoresis and multilocus sequencing to establish the clonal relatedness of O121 isolates and to elucidate the relationship of O121 to common STEC clones. The 24 isolates were found to represent a single bacterial clone, as there was no allelic variation across 18 enzyme loci among the isolates. The complete nucleotide sequence of the intimin gene differed by four substitutions from that of the epsilon (Int-ε) allele of O103:H2 strain PMK5. The typical O121 virulence gene profile was similar to the profiles of enterohemorrhagic E. coli (EHEC) clones of E. coli: it included a Shiga toxin 2 gene (stx 2), two genes on the EHEC plasmid (toxB and ehxA), and the gene encoding intimin (eae). Despite the similarities, putative virulence genes distributed on O islands—large chromosomal DNA segments present in the O157:H7 genome—were useful for discriminating among STEC serotypes and the O121:H19 clone had a composite profile that was distinct from the profiles of the other major EHEC clones of pathogenic E. coli. On the basis of sequencing analysis with 13 housekeeping genes, the O121:H19 clone did not fall into any of the four classical EHEC and enteropathogenic E. coli groups but instead was closely related to two eae-negative STEC strains.

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