Article

Atypical Enteropathogenic Escherichia coli Infection and Prolonged Diarrhea in Children

University of Melbourne, Parkville, Victoria, Australia.
Emerging infectious diseases (Impact Factor: 7.33). 05/2006; 12(4):597-603. DOI: 10.3201/eid1204.051112
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ABSTRACT Some clinical isolates of enteropathogenic Escherichia coli (EPEC) lack bundle-forming pili and are termed atypical EPEC. The aim of this study was to determine if atypical EPEC are pathogens by comparing the clinical features of patients infected with atypical EPEC with those of children infected with other causative agents of diarrhea. Fecal samples obtained from children attending the Royal Children's Hospital in Melbourne for investigation of diarrhea were examined for adenovirus, rotavirus, Campylobacter spp., Salmonella spp., protozoa, and pathogenic E. coli. Clinical data were obtained by using a standardized pro forma and analyzed separately. Patients infected with atypical EPEC experienced mild, nondehydrating, and noninflammatory diarrhea that was not particularly associated with fever, vomiting, or abdominal pain. However, the duration of diarrhea in patients infected with atypical EPEC was significantly longer than that caused by the other species or where no pathogens were identified. Infection with atypical EPEC is associated with prolonged diarrhea.

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    • "Other than the binding of EAEC to the epithelial cell, it is known that this bacterium expresses enterotoxins and cytotoxins, including the Pet toxin, which leads to a secretory diarrhea and mucosal inflammation [13]. Atypical enteropathogenic Escherichia coli (aEPEC) have been associated with both acute childhood diarrhea [14] [15] [16] and persistent diarrhea [17] [18]. However, their pathogenicity is controversial since aEPEC have also been found in diarrheic and nondiarrheic patients. "
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    ABSTRACT: Plasmid encoded toxin (Pet) is a serine protease originally described in enteroaggregative Escherichia coli (EAEC) prototype strain 042 whose entire characterization was essentially obtained from studies performed with the purified toxin. Here we show that Pet is not exclusive to EAEC. Atypical enteropathogenic Escherichia coli (aEPEC) strains, isolated from diarrhea cases, express Pet and its detection in supernatants of infected HEp-2 cells coincides with the appearance of cell damage, which, in turn, were similar to those described with purified Pet. Pet secretion and the cytotoxic effects are time and culture medium dependent. In presence of DMEM supplemented with tryptone cell rounding and detachment were observed after just 5 h of incubation with the bacteria. In the absence of tryptone, the cytotoxic effects were detected only after 24 h of infection. We also show that, in addition to the prototype EAEC, other pet+ EAEC strains, also isolated from diarrhea cases, induce cellular damage in the same degree as the aEPEC. The cytotoxic effects of EAEC and aEPEC strains were significantly reduced in the presence of a serine protease inhibitor or anti-Pet IgG serum. Our results show a common aspect between the aEPEC and EAEC and provide the first evidence pointing to a role of Pet in aEPEC pathogenesis.
    BioMed Research International 05/2014; 2014:896235. DOI:10.1155/2014/896235 · 2.71 Impact Factor
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    • "EPEC infection is primarily a disease of infants younger than 2 years of age. Nguyen et al. (2006) found that atypical EPEC generally occurred in children ,2 years of age. Afset et al. (2003) found that EPEC was significantly more common among children who were 12–23 months old than in those who were 12 months of age. "
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    ABSTRACT: Aims: To investigate the incidence, antimicrobial resistance and the genetic relationships of enteropathogenic Escherichia coli (EPEC) in children with diarrhea. Methods and Results: Disk diffusion method was used to determine the susceptibility of the isolates as instructed by Clinical and Laboratory Standards Institute (CLSI). The presence of eae, stx, bfp-A genes was determined by polymerase chain reaction (PCR). The genetic relationships of EPEC isolates were determined by pulsed-field gel electrophoresis (PFGE). Out of the 412 E. coli obtained from 612 diarrheal stool specimens, 23 (5.6%) were EPEC, among which 7 (30.4%) strains were classified as typical EPEC and 16 (69.6%) strains as atypical EPEC strains. Out of the 23 EPEC isolates, 69.5% were resistant to ampicillin, 39.1% were resistant to tetracycline and cotrimoxazole, 30.4% were resistant to cefpodoxime, ceftazidime, ceftriaxone and aztreonam, and 26.1% were resistant to imipenem. The isolates were classified in 21 pulsotypes by PFGE profiles. Conclusions: The present study shows that typical and atypical EPEC isolates had considerable heterogeneity in PFGE profiles and EPEC infections were sporadic in Tehran. Overall 69% of isolates were resistant to at least one of the antibiotics tested.
    Journal of Medical Microbiology 10/2012; 62(Pt_2). DOI:10.1099/jmm.0.046516-0 · 2.27 Impact Factor
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    • "Historically, most cases of EPEC in industrialized countries have been associated with typical strains, but more recently aEPEC strains have been linked to outbreaks of human disease affecting both adults and children around the world (Bokete et al. 1997, Hedberg et al. 1997, Yatsuyanagi et al., 2002, Afset et al. 2003, Nataro 2006, Nguyen et al. 2006, Afset et al. 2008). More recently, Nguyen et al. (2006) reported that patients infected with aEPEC strains were more likely to experience diarrhea lasting longer than two weeks, increasing the risk for serious illness and death. Taken together, these results indicate that aEPEC strains in contaminated recreational water may represent a public health risk to swimmers. "
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    ABSTRACT: Contamination of recreational waters with Escherichia coli and Enterococcus sp. is a widespread problem resulting in beach closures and loss of recreational activity. While E. coli is frequently used as an indicator of fecal contamination, and has been extensively measured in waterways, few studies have examined the presence of potentially pathogenic E. coli strains in beach waters. In this study, a combination of high-throughput, robot-assisted colony hybridization and PCR-based analyses were used to determine the genomic composition and frequency of virulence genes present in E. coli isolated from beach water in Avalon Bay, Santa Catalina Island, CA. A total of 24,493 E. coli isolates were collected from two sites at a popular swimming beach between August through September 2007 and from July through August 2008. All isolates were examined for the presence of shiga-like toxins (stx1/stx2), intimin (eaeA), and enterotoxins (ST/LT). Of the 24,493 isolates examined, 3.6% contained the eaeA gene, indicating that these isolates were potential EPEC strains. On five dates, however, greater than 10% of the strains were potential EPEC, suggesting that incidence of virulence genes at this beach has a strong temporal component. No STEC or ETEC isolates were detected, and only eight (<1.0%) of the potential EPEC isolates were found to carry the EAF plasmid. The potential EPEC isolates mainly belonged to E. coli phylogenetic groups B1 or B2, and carried the β intimin subtype. DNA fingerprint analyses of the potential EPEC strains indicated that the isolates belonged to several genetically diverse groups, although clonal isolates were frequently detected. While the presence of virulence genes alone cannot be used to determine the pathogenicity of strains, results from this study show that potential EPEC strains can be found in marine beach water and their presence needs to be considered as one of the factors used in decisions concerning beach closures.
    Water Research 10/2010; 44(18):5463-73. DOI:10.1016/j.watres.2010.06.058 · 5.32 Impact Factor
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