Assessing the public health risk of Shiga toxin-producing Escherichia coli by use of a rapid diagnostic screening algorithm.
J Clin Microbiol
; 53(5): 1588-98, 2015 May.
Article
en En
| MEDLINE
| ID: mdl-25740764
ABSTRACT
Shiga toxin-producing Escherichia coli (STEC) is an enteropathogen of public health concern because of its ability to cause serious illness and outbreaks. In this prospective study, a diagnostic screening algorithm to categorize STEC infections into risk groups was evaluated. The algorithm consists of prescreening stool specimens with real-time PCR (qPCR) for the presence of stx genes. The qPCR-positive stool samples were cultured in enrichment broth and again screened for stx genes and additional virulence factors (escV, aggR, aat, bfpA) and O serogroups (O26, O103, O104, O111, O121, O145, O157). Also, PCR-guided culture was performed with sorbitol MacConkey agar (SMAC) and CHROMagar STEC medium. The presence of virulence factors and O serogroups was used for presumptive pathotype (PT) categorization in four PT groups. The potential risk for severe disease was categorized from high risk for PT group I to low risk for PT group III, whereas PT group IV consists of unconfirmed stx qPCR-positive samples. In total, 5,022 stool samples of patients with gastrointestinal symptoms were included. The qPCR detected stx genes in 1.8% of samples. Extensive screening for virulence factors and O serogroups was performed on 73 samples. After enrichment, the presence of stx genes was confirmed in 65 samples (89%). By culture on selective media, STEC was isolated in 36% (26/73 samples). Threshold cycle (CT) values for stx genes were significantly lower after enrichment compared to direct qPCR (P < 0.001). In total, 11 (15%), 19 (26%), 35 (48%), and 8 (11%) samples were categorized into PT groups I, II, III, and IV, respectively. Several virulence factors (stx2, stx2a, stx2f, toxB, eae, efa1, cif, espA, tccP, espP, nleA and/or nleB, tir cluster) were associated with PT groups I and II, while others (stx1, eaaA, mch cluster, ireA) were associated with PT group III. Furthermore, the number of virulence factors differed between PT groups (analysis of variance, P < 0.0001). In conclusion, a diagnostic algorithm enables fast discrimination of STEC infections associated with a high to moderate risk for severe disease (PT groups I and II) from less-virulent STEC (PT group III).
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Algoritmos
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Tamizaje Masivo
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Técnicas Bacteriológicas
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Infecciones por Escherichia coli
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Escherichia coli Shiga-Toxigénica
Tipo de estudio:
Diagnostic_studies
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Etiology_studies
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Evaluation_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
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Screening_studies
Límite:
Adolescent
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Adult
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Aged
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Aged80
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Child
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Child, preschool
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Female
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Humans
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Infant
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Male
Idioma:
En
Revista:
J Clin Microbiol
Año:
2015
Tipo del documento:
Article
País de afiliación:
Países Bajos