The significance of enteroaggregative Escherichia coli in the etiology of hospitalized diarrhoea in Calcutta, India and the demonstration of a new honey-combed pattern of aggregative adherence

Abstract

Previous studies have identified enteroadherent Escherichia coli that exhibit localized adherence, diffuse adherence and atypical diffuse adherence as diarrhoeagenic agents associated with infantile diarrhoea in Calcutta, India. In this study, a DNA probe specific for enteroaggregative adherence was used to determine the etiological significance of enteroaggregative E. coli in the causation of diarrhoea. From a total of 330 strains of E. coli recovered from 159 cases of acute secretory diarrhoea and 174 cases of invasive diarrhoea, 20 strains hybridized with the probe, whereas of the 25 E. coli strains recovered from 25 healthy controls only 1 strain hybridized with the probe. Of the 21 probe positive strains, 19 adhered to HeLa cells in the typical stacked-brick pattern while 2 strains recovered from 2 cases of secretory diarrhoea adhered to the glass surface in a hitherto undescribed formation which we have termed, based on the appearance, as the honey-comb pattern. The enteroaggregative E. coli strains identified in this study did not produce any conventional enterotoxins and were significantly associated with patients with secretory diarrhoea (10.7%) than with invasive diarrhoea (1.7%). The results of this study indicate that enteroaggregative E. coli play a causal role in acute secretory diarrhoea in this part of the world which lends credence to the involvement of a potent toxin in the pathogenesis of EAggEC mediated infections.

Pathotypes of diarrheagenic Escherichia coli in children attending a tertiary care hospital in South India

“…In this study, the aap and aggR combination was seen in 19 (4.8%) cases and 10 (5.1%) controls, while the aap gene alone was more common in controls (29, 14.6%) than cases (13, 3.3%). Previous reports from India using adherence assays, PCR, and biofilm production have reported a high prevalence of EAEC in cases (Dutta et al, 1999; Kahali et al, 2004; Paul et al, 1994); however, our study found high rates of detection of astA , aap , and aggR in controls, and only the combination of aap , aggR , and AA was significantly associated with disease. There was no overlap between the aafII gene detected in the multiplex DEC PCR and the other 2 EAEC PCRs.…”

Roles for Fis and YafK in biofilm formation by enteroaggregative Escherichia coli

“…We have reported previously that many EAEC strains adhere abundantly to the glass substratum in the HEp‐2 adherence assay, in which bacteria are added to a semi‐confluent monolayer of cells in the presence of mannose and tissue culture medium (Nataro et al ., 1987). In this assay, our prototype EAEC strain 042 adheres abundantly to the glass substratum in a characteristic honeycomb pattern, as described previously (Paul et al ., 1994). To understand this phenomenon better, we observed 042 grown in minimal essential medium with 0.4% glucose (here called high‐glucose MEM) at 37°C, in the absence of HEp‐2 cells, for time points between 1 h and 72 h (Fig.…”

EnteroaggregativeEscherichia colipathotype: a genetically heterogeneous emerging foodborne enteropathogen

“…The clinical features of EAEC illness have been defined from volunteer studies, outbreaks, or sporadic cases, which include watery secretory diarrhea, often with mucus, with or without blood, low‐grade fever, abdominal pain, nausea, and vomiting (Bhan et al ., ; Paul et al ., ; Nataro et al ., ; Adachi et al ., ). Although bloody diarrhea is not a distinctive feature of EAEC illness, Cravioto et al .…”