{"title":"实时荧光定量PCR (qPCR)检测腹泻患儿与无症状感染患儿肠聚集性大肠杆菌(EAEC)菌量比较","authors":"David Durand, Joaquim Ruíz, Theresa J Ochoa","doi":"10.1016/j.eimce.2025.05.003","DOIUrl":null,"url":null,"abstract":"<p><strong>Introduction: </strong>Enteroaggregative Escherichia coli (EAEC) is a pathotype of diarrheagenic E. coli (DEC) that causes acute and persistent diarrhoea in children, HIV-infected patients and travelers. However, EAEC can also be isolated in people without diarrhoea. The aim of this study was to evaluated if the EAEC bacterial load in stool samples is associated with diarrhoea in comparison with asymptomatic infection.</p><p><strong>Methods: </strong>We selected 165 stool samples (children with diarrhoea: 80 and asymptomatic children: 85) that previously were identified as EAEC by Real-Time PCR for diagnostic of DEC from E. coli isolated from stool cultures. We extracted DNA from fecal samples using the cetyltrimethylammonium bromide (CTAB) method and standardised a qPCR to evaluate the bacterial load using EAEC strain 042.</p><p><strong>Results: </strong>The detection limit of the qPCR was 10 copies ofaggR gene (5 bacterias)/mg stool and the reaction efficiency was ≥ 93%. We found a higher bacterial load in patients with diarrhoea [2781, 95% CI (688-6875) bacteria/mg feces] than in asymptomatic children [138, 95% CI (75-306) bacteria/mg feces], including samples with single pathogen infection and co-infections. Among diarrheal samples, the bacterial load was higher in boys than girls and in children older than 18 months than younger.</p><p><strong>Conclusions: </strong>EAEC load in stool samples are higher in children with diarrhoea than in asymptomatic infection. This qPCR could be useful for studying the role of colonisation in children living in endemic areas where the isolation of this pathogen is similar in both groups.</p>","PeriodicalId":72916,"journal":{"name":"Enfermedades infecciosas y microbiologia clinica (English ed.)","volume":" ","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Bacterial load comparison of enteroaggregative Escherichia coli (EAEC) by real-time PCR (qPCR) between children with diarrhea and asymptomatic infection.\",\"authors\":\"David Durand, Joaquim Ruíz, Theresa J Ochoa\",\"doi\":\"10.1016/j.eimce.2025.05.003\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Introduction: </strong>Enteroaggregative Escherichia coli (EAEC) is a pathotype of diarrheagenic E. coli (DEC) that causes acute and persistent diarrhoea in children, HIV-infected patients and travelers. However, EAEC can also be isolated in people without diarrhoea. The aim of this study was to evaluated if the EAEC bacterial load in stool samples is associated with diarrhoea in comparison with asymptomatic infection.</p><p><strong>Methods: </strong>We selected 165 stool samples (children with diarrhoea: 80 and asymptomatic children: 85) that previously were identified as EAEC by Real-Time PCR for diagnostic of DEC from E. coli isolated from stool cultures. We extracted DNA from fecal samples using the cetyltrimethylammonium bromide (CTAB) method and standardised a qPCR to evaluate the bacterial load using EAEC strain 042.</p><p><strong>Results: </strong>The detection limit of the qPCR was 10 copies ofaggR gene (5 bacterias)/mg stool and the reaction efficiency was ≥ 93%. We found a higher bacterial load in patients with diarrhoea [2781, 95% CI (688-6875) bacteria/mg feces] than in asymptomatic children [138, 95% CI (75-306) bacteria/mg feces], including samples with single pathogen infection and co-infections. Among diarrheal samples, the bacterial load was higher in boys than girls and in children older than 18 months than younger.</p><p><strong>Conclusions: </strong>EAEC load in stool samples are higher in children with diarrhoea than in asymptomatic infection. This qPCR could be useful for studying the role of colonisation in children living in endemic areas where the isolation of this pathogen is similar in both groups.</p>\",\"PeriodicalId\":72916,\"journal\":{\"name\":\"Enfermedades infecciosas y microbiologia clinica (English ed.)\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2025-05-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Enfermedades infecciosas y microbiologia clinica (English ed.)\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1016/j.eimce.2025.05.003\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Enfermedades infecciosas y microbiologia clinica (English ed.)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1016/j.eimce.2025.05.003","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Bacterial load comparison of enteroaggregative Escherichia coli (EAEC) by real-time PCR (qPCR) between children with diarrhea and asymptomatic infection.
Introduction: Enteroaggregative Escherichia coli (EAEC) is a pathotype of diarrheagenic E. coli (DEC) that causes acute and persistent diarrhoea in children, HIV-infected patients and travelers. However, EAEC can also be isolated in people without diarrhoea. The aim of this study was to evaluated if the EAEC bacterial load in stool samples is associated with diarrhoea in comparison with asymptomatic infection.
Methods: We selected 165 stool samples (children with diarrhoea: 80 and asymptomatic children: 85) that previously were identified as EAEC by Real-Time PCR for diagnostic of DEC from E. coli isolated from stool cultures. We extracted DNA from fecal samples using the cetyltrimethylammonium bromide (CTAB) method and standardised a qPCR to evaluate the bacterial load using EAEC strain 042.
Results: The detection limit of the qPCR was 10 copies ofaggR gene (5 bacterias)/mg stool and the reaction efficiency was ≥ 93%. We found a higher bacterial load in patients with diarrhoea [2781, 95% CI (688-6875) bacteria/mg feces] than in asymptomatic children [138, 95% CI (75-306) bacteria/mg feces], including samples with single pathogen infection and co-infections. Among diarrheal samples, the bacterial load was higher in boys than girls and in children older than 18 months than younger.
Conclusions: EAEC load in stool samples are higher in children with diarrhoea than in asymptomatic infection. This qPCR could be useful for studying the role of colonisation in children living in endemic areas where the isolation of this pathogen is similar in both groups.