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Theresa J. Ochoa - One of the best experts on this subject based on the ideXlab platform.

  • Diarrheagenic Escherichia Coli: Prevalence and Pathotype Distribution in Children from Peruvian Rural Communities
    The American journal of tropical medicine and hygiene, 2016
    Co-Authors: Gonzalo J. Acosta, David Durand, Natalia I. Vigo, Maribel Riveros, Sara Arango, Mara Zambruni, Theresa J. Ochoa
    Abstract:

    Abstract Diarrheagenic Escherichia Coli (DEC) are common pathogens of childhood gastrointestinal infections worldwide. To date, research tracking DEC has mainly been completed in urban areas. This study aims to determine the prevalence and pathotype distribution of DEC strains in children from rural Peruvian communities and to establish their association with malnutrition. In this prospective cohort, 93 children aged 6–13 months from rural communities of Urubamba (Andes) and Moyobamba (jungle) were followed for 6 months. Diarrheal and control stool samples were analyzed using multiplex real-time polymerase chain reaction to identify the presence of virulence genes of DEC strains. The overall isolation rate of DEC was 43.0% (352/820). Enteroaggregative E. Coli (EAEC, 20.4%), enteropathogenic E. Coli (EPEC, 14.2%), and diffusely aggregative E. Coli (DAEC, 11.0%) were the most prevalent pathotypes. EAEC was more frequently found in Moyobamba samples (P < 0.01). EPEC was the only strain significantly more frequent in diarrheal than asymptomatic control samples (P < 0.01). DEC strains were more prevalent among younger children (aged 6–12 months, P < 0.05). A decline in height-for-age Z-score (HAZ) was observed in 75.7% of children overall. EAEC was more frequently isolated among children who had a greater HAZ decline (P < 0.05). In conclusion, DEC strains were frequently found in stool samples from children in rural communities of the highlands and jungle of Peru. In addition, children with a greater decline in their growth rate had higher EAEC isolation rates, highlighting the importance of this pathogen in child malnutrition.

  • Fecal Leukocytes in Children Infected with Diarrheagenic Escherichia Coli
    Journal of clinical microbiology, 2011
    Co-Authors: Erik Mercado, Francesca Barletta, Theresa J. Ochoa, Lucie Ecker, Martin Cabello, David Durand, Margarita Molina, Ana I. Gil, Luis Huicho, Claudio F. Lanata
    Abstract:

    The purpose of this study was to determine the presence and quantity of fecal leukocytes in children infected with Diarrheagenic Escherichia Coli and to compare these levels between diarrhea and control cases. We analyzed 1,474 stool samples from 935 diarrhea episodes and 539 from healthy controls of a cohort study of children younger than 2 years of age in Lima, Peru. Stools were analyzed for common enteric pathogens, and Diarrheagenic E. Coli isolates were studied by a multiplex real-time PCR. Stool smears were stained with methylene blue and read by a blinded observer to determine the number of polymorphonuclear leukocytes per high-power field (L/hpf). Fecal leukocytes at >10 L/hpf were present in 11.8% (110/935) of all diarrheal episodes versus 1.1% (6/539) in controls (P 10 L/hpf were present in 8.5% (18/212) of diarrhea versus 1.3% (2/157) of control samples (P 10 L/hpf) with an odds ratio (OR) of 4.1 (95% confidence interval [CI], 1.08 to 15.51; P < 0.05). Although Diarrheagenic E. Coli was isolated with similar frequencies in diarrhea and control samples, clearly it was associated with a more inflammatory response during symptomatic infection; however, in general, these pathogens elicited a mild inflammatory response.

  • Validation of Five-Colony Pool Analysis Using Multiplex Real-Time PCR for Detection of Diarrheagenic Escherichia Coli
    Journal of clinical microbiology, 2009
    Co-Authors: Francesca Barletta, Theresa J. Ochoa, L. Ecker, A. I. Gil, Claudio F. Lanata, Thomas G. Cleary
    Abstract:

    Five Escherichia Coli colonies/patient were studied to evaluate the reliability of a multiplex real-time PCR assay for detection of Diarrheagenic Escherichia Coli groups, using a pool of five colonies rather than individual colonies. Sensitivity and specificity were 98% and 100%, respectively, at a fifth of the cost of the individual colony analysis.

  • Detection of Diarrheagenic Escherichia Coli by Use of Melting-Curve Analysis and Real-Time Multiplex PCR
    Journal of clinical microbiology, 2008
    Co-Authors: Chase E. Guionc.e. Guion, Francesca Barletta, Theresa J. Ochoa, Christopher M. Walker, Thomas G. Cleary
    Abstract:

    Diarrheagenic Escherichia Coli strains are important causes of diarrhea in children from the developing world and are now being recognized as emerging enteropathogens in the developed world. Current methods of detection are too expensive and labor-intensive for routine detection of these organisms to be practical. We developed a real-time fluorescence-based multiplex PCR for the detection of all six of the currently recognized classes of Diarrheagenic E. Coli. The primers were designed to specifically amplify eight different virulence genes in the same reaction: aggR for enteroaggregative E. Coli, stIa/stIb and lt for enterotoxigenic E. Coli, eaeA for enteropathogenic E. Coli and Shiga toxin-producing E. Coli (STEC), stx1 and stx2 for STEC, ipaH for enteroinvasive E. Coli, and daaD for diffusely adherent E. Coli (DAEC). Eighty-nine of ninety Diarrheagenic E. Coli and 36/36 nonpathogenic E. Coli strains were correctly identified using this approach (specificity, 1.00; sensitivity, 0.99). The single false negative was a DAEC strain. The total time between preparation of DNA from E. Coli colonies on agar plates and completion of PCR and melting-curve analysis was less than 90 min. The cost of materials was low. Melting-point analysis of real-time multiplex PCR is a rapid, sensitive, specific, and inexpensive method for detection of Diarrheagenic E. Coli.

Thomas G. Cleary - One of the best experts on this subject based on the ideXlab platform.

  • Validation of Five-Colony Pool Analysis Using Multiplex Real-Time PCR for Detection of Diarrheagenic Escherichia Coli
    Journal of clinical microbiology, 2009
    Co-Authors: Francesca Barletta, Theresa J. Ochoa, L. Ecker, A. I. Gil, Claudio F. Lanata, Thomas G. Cleary
    Abstract:

    Five Escherichia Coli colonies/patient were studied to evaluate the reliability of a multiplex real-time PCR assay for detection of Diarrheagenic Escherichia Coli groups, using a pool of five colonies rather than individual colonies. Sensitivity and specificity were 98% and 100%, respectively, at a fifth of the cost of the individual colony analysis.

  • Detection of Diarrheagenic Escherichia Coli by Use of Melting-Curve Analysis and Real-Time Multiplex PCR
    Journal of clinical microbiology, 2008
    Co-Authors: Chase E. Guionc.e. Guion, Francesca Barletta, Theresa J. Ochoa, Christopher M. Walker, Thomas G. Cleary
    Abstract:

    Diarrheagenic Escherichia Coli strains are important causes of diarrhea in children from the developing world and are now being recognized as emerging enteropathogens in the developed world. Current methods of detection are too expensive and labor-intensive for routine detection of these organisms to be practical. We developed a real-time fluorescence-based multiplex PCR for the detection of all six of the currently recognized classes of Diarrheagenic E. Coli. The primers were designed to specifically amplify eight different virulence genes in the same reaction: aggR for enteroaggregative E. Coli, stIa/stIb and lt for enterotoxigenic E. Coli, eaeA for enteropathogenic E. Coli and Shiga toxin-producing E. Coli (STEC), stx1 and stx2 for STEC, ipaH for enteroinvasive E. Coli, and daaD for diffusely adherent E. Coli (DAEC). Eighty-nine of ninety Diarrheagenic E. Coli and 36/36 nonpathogenic E. Coli strains were correctly identified using this approach (specificity, 1.00; sensitivity, 0.99). The single false negative was a DAEC strain. The total time between preparation of DNA from E. Coli colonies on agar plates and completion of PCR and melting-curve analysis was less than 90 min. The cost of materials was low. Melting-point analysis of real-time multiplex PCR is a rapid, sensitive, specific, and inexpensive method for detection of Diarrheagenic E. Coli.

Francesca Barletta - One of the best experts on this subject based on the ideXlab platform.

  • Fecal Leukocytes in Children Infected with Diarrheagenic Escherichia Coli
    Journal of clinical microbiology, 2011
    Co-Authors: Erik Mercado, Francesca Barletta, Theresa J. Ochoa, Lucie Ecker, Martin Cabello, David Durand, Margarita Molina, Ana I. Gil, Luis Huicho, Claudio F. Lanata
    Abstract:

    The purpose of this study was to determine the presence and quantity of fecal leukocytes in children infected with Diarrheagenic Escherichia Coli and to compare these levels between diarrhea and control cases. We analyzed 1,474 stool samples from 935 diarrhea episodes and 539 from healthy controls of a cohort study of children younger than 2 years of age in Lima, Peru. Stools were analyzed for common enteric pathogens, and Diarrheagenic E. Coli isolates were studied by a multiplex real-time PCR. Stool smears were stained with methylene blue and read by a blinded observer to determine the number of polymorphonuclear leukocytes per high-power field (L/hpf). Fecal leukocytes at >10 L/hpf were present in 11.8% (110/935) of all diarrheal episodes versus 1.1% (6/539) in controls (P 10 L/hpf were present in 8.5% (18/212) of diarrhea versus 1.3% (2/157) of control samples (P 10 L/hpf) with an odds ratio (OR) of 4.1 (95% confidence interval [CI], 1.08 to 15.51; P < 0.05). Although Diarrheagenic E. Coli was isolated with similar frequencies in diarrhea and control samples, clearly it was associated with a more inflammatory response during symptomatic infection; however, in general, these pathogens elicited a mild inflammatory response.

  • Diarrheagenic Escherichia Coli in Human Immunodeficiency Virus (HIV) Pediatric Patients in Lima, Perú
    The American journal of tropical medicine and hygiene, 2010
    Co-Authors: Anicia M. Medina, Francesca Barletta, Fulton P. Rivera, Liliana M. Romero, Lenka Kolevic, María E. Castillo, Eduardo Verne, Roger Hernandez, Yovanna E. Mayor, Erik Mercado
    Abstract:

    We conducted a prospective study in three hospitals in Lima in human immunodeficiency virus (HIV) children to determine the frequency of Diarrheagenic Escherichia Coli. Five E. Coli colonies/patients were studied by a multiplex real-time polymerase chain reaction to identify the six currently recognized groups of diarrhea-associated E. Coli. We have analyzed 70 HIV-associated diarrheal and 70 control samples from HIV-infected children without diarrhea. Among the diarrheal episodes 19% were persistent, 3% dysenteric, and 33% were associated with moderate or severe dehydration. The Diarrheagenic E. Coli were the most commonly isolated pathogens in diarrhea (19%) and control samples (26%) (P = 0.42), including enteroaggregative (6% versus 10%), enteropathogenic (6% versus 10%), and enterotoxigenic E. Coli (4% versus 3%), respectively. The HIV-infected children with diarrhea had the worse age-related immunosuppression, higher viral loads, and were on highly active antiretroviral treatment (HAART) less often than HIV-infected children without diarrhea. Diarrheagenic E. Coli were highly resistant to ampicillin (74%) and cotrimoxazole (70%).

  • Validation of Five-Colony Pool Analysis Using Multiplex Real-Time PCR for Detection of Diarrheagenic Escherichia Coli
    Journal of clinical microbiology, 2009
    Co-Authors: Francesca Barletta, Theresa J. Ochoa, L. Ecker, A. I. Gil, Claudio F. Lanata, Thomas G. Cleary
    Abstract:

    Five Escherichia Coli colonies/patient were studied to evaluate the reliability of a multiplex real-time PCR assay for detection of Diarrheagenic Escherichia Coli groups, using a pool of five colonies rather than individual colonies. Sensitivity and specificity were 98% and 100%, respectively, at a fifth of the cost of the individual colony analysis.

  • Detection of Diarrheagenic Escherichia Coli by Use of Melting-Curve Analysis and Real-Time Multiplex PCR
    Journal of clinical microbiology, 2008
    Co-Authors: Chase E. Guionc.e. Guion, Francesca Barletta, Theresa J. Ochoa, Christopher M. Walker, Thomas G. Cleary
    Abstract:

    Diarrheagenic Escherichia Coli strains are important causes of diarrhea in children from the developing world and are now being recognized as emerging enteropathogens in the developed world. Current methods of detection are too expensive and labor-intensive for routine detection of these organisms to be practical. We developed a real-time fluorescence-based multiplex PCR for the detection of all six of the currently recognized classes of Diarrheagenic E. Coli. The primers were designed to specifically amplify eight different virulence genes in the same reaction: aggR for enteroaggregative E. Coli, stIa/stIb and lt for enterotoxigenic E. Coli, eaeA for enteropathogenic E. Coli and Shiga toxin-producing E. Coli (STEC), stx1 and stx2 for STEC, ipaH for enteroinvasive E. Coli, and daaD for diffusely adherent E. Coli (DAEC). Eighty-nine of ninety Diarrheagenic E. Coli and 36/36 nonpathogenic E. Coli strains were correctly identified using this approach (specificity, 1.00; sensitivity, 0.99). The single false negative was a DAEC strain. The total time between preparation of DNA from E. Coli colonies on agar plates and completion of PCR and melting-curve analysis was less than 90 min. The cost of materials was low. Melting-point analysis of real-time multiplex PCR is a rapid, sensitive, specific, and inexpensive method for detection of Diarrheagenic E. Coli.

Isabel C. A. Scaletsky - One of the best experts on this subject based on the ideXlab platform.

  • Real-time multiplex PCR assay and melting curve analysis for identifying Diarrheagenic Escherichia Coli
    Journal of clinical microbiology, 2013
    Co-Authors: Tamara B. Souza, Diego M. Lozer, Sônia M. S. Kitagawa, Liliana Cruz Spano, Neusa Pereira Da Silva, Isabel C. A. Scaletsky
    Abstract:

    ABSTRACT A real-time multiplex PCR assay was designed to amplify the virulence genes eae , pEAF, aatA , daaC , elt , est , ipaH , stx 1 , and stx 2 for the detection of all Diarrheagenic Escherichia Coli pathotypes. This assay proved to be more sensitive and rapid than a conventional multiplex PCR for Diarrheagenic E. Coli isolates from children with diarrhea.

  • High prevalence of antimicrobial drug-resistant Diarrheagenic Escherichia Coli in asymptomatic children living in an urban slum.
    The Journal of infection, 2009
    Co-Authors: Tamara B. Souza, Mauro Batista De Morais, Soraia Tahan, Lígia C. F. L. Melli, Mirian Silva Do Carmo Rodrigues, Isabel C. A. Scaletsky
    Abstract:

    Summary Purpose The aim of this study was to investigate the presence of Diarrheagenic Escherichia Coli and antibiotic resistance in asymptomatic school-age children living in an area with defective environmental sanitation, comparing with children registered at a private school, both in the city of Osasco, Brazil. Methods Seventy-nine school-age children between 5 and 10 years living in a slum and 35 children who attended a private school of the same city were included in the study. Results DEC was found in 58% of the children living in the slum and in 17% of the control group ( P =0.001). Resistance to at least one antimicrobial drug was found in 65% of DEC strains; resistant to two or more antimicrobial drugs was found in 46% of strains. Conclusion The high carriage status among the slum children point towards the widespread environment contamination in low socio-economic housing conditions, in conformance with the pediatric population at higher risk for developing DEC diarrhea.

Roberto Vidal - One of the best experts on this subject based on the ideXlab platform.