Molina Nora Beatriz, Oderiz Sebastián, López Marisa Ana, Basualdo Juan Ángel, Sparo Mónica Delfina
Centro Universitario de Estudios Microbiológicos y Parasitológicos, Comisión de Investigaciones Científicas, Universidad Nacional de La Plata, La Plata, Buenos Aires , Argentina.
Sala de Microbiología, Hospital Interzonal de Niños Sor María Ludovica, La Plata, Buenos Aires , Argentina.
Rev Argent Microbiol. 2024 Jan-Mar;56(1):8-15. doi: 10.1016/j.ram.2023.06.002. Epub 2023 Jul 25.
Diarrheagenic Escherichia coli comprises a heterogeneous group of pathotypes or pathogenic variants that share phenotypic characteristics with marked differences in virulence genes, colonization sites, pathogenesis, clinical presentation, and epidemiology of infection. The most studied pathotypes are Shiga toxin-producing E.coli (STEC), enterotoxigenic E.coli (ETEC), enteropathogenic E.coli (EPEC), enteroaggregative E.coli (EAEC), and enteroinvasive E.coli (EIEC). The objective of the study was to characterize the isolates of diarrheagenic E.coli from an outpatient pediatric population with diarrhea attended in two public hospitals from Buenos Aires, Argentina. Diarrheagenic E.coli pathotypes were investigated by amplifying characteristic virulence gene fragments: intimin (eae), heat-labile toxin (lt), heat-stable toxins (stp, sth), invasion plasmid antigen H (ipaH), transcriptional activator R (aggR) and Shiga toxins (stx1, stx2). Molecular subtyping of isolates was performed using PFGE (XbaI). Diarrheagenic E.coli was detected in 14% (84/601) of cases. The EAEC pathotype was prevalent, while ETEC, STEC, EPEC and EIEC were found in a lower proportion. EAEC isolates exhibited a high degree of genetic diversity. All pathotypes were found in children under 5years of age, while only EAEC, EIEC and ETEC were detected in the older population. Future studies that include the characterization of isolates from a greater number of genes and populations from other geographical areas will be necessary to determine the relevance of diarrheagenic E.coli in Argentina.
致泻性大肠杆菌包括一组异质性的致病型或致病变体，它们具有共同的表型特征，但在毒力基因、定植部位、发病机制、临床表现和感染流行病学方面存在显著差异。研究最多的致病型是产志贺毒素大肠杆菌（STEC）、肠毒素性大肠杆菌（ETEC）、肠致病性大肠杆菌（EPEC）、肠聚集性大肠杆菌（EAEC）和肠侵袭性大肠杆菌（EIEC）。本研究的目的是对来自阿根廷布宜诺斯艾利斯两家公立医院就诊的腹泻门诊儿科患者的致泻性大肠杆菌分离株进行特征分析。通过扩增特征性毒力基因片段来研究致泻性大肠杆菌致病型：紧密黏附素（eae）、不耐热毒素（lt）、耐热毒素（stp、sth）、侵袭质粒抗原H（ipaH）、转录激活因子R（aggR）和志贺毒素（stx1、stx2）。使用PFGE（XbaI）对分离株进行分子分型。在14%（84/601）的病例中检测到致泻性大肠杆菌。EAEC致病型最为普遍，而ETEC、STEC、EPEC和EIEC的比例较低。EAEC分离株表现出高度的遗传多样性。所有致病型在5岁以下儿童中均有发现，而在年龄较大的人群中仅检测到EAEC、EIEC和ETEC。未来有必要开展包括对来自更多基因和其他地理区域人群的分离株进行特征分析的研究，以确定致泻性大肠杆菌在阿根廷的相关性。
