Colonization with enteroadherent, enterotoxigenic and enterohemorrhagic Escherichia coli among day-care center attendees in New Orleans, Louisiana

The trend of enteropathogenic Escherichia coli towards atypical multidrug resistant genotypes

The aim of this study was to investigate the prevalence of multidrug resistance (MDR) in atypical enteropathogenic Escherichia coli (EPEC) genotypes among 547 diarrheal children. All E. coli isolates with eae⁺stx1^-stx2^- genotypes included in this study and atypical property of EPEC was characterized by the absence of Bundle-forming pili (bfpA gene). Bacterial pathogens were detected in 70 patients (12.8%) among which atypical EPEC (5.3%) were the most common. The higher resistance rate was seen to tetracycline (70%), cotrimoxazole (60%) and nalidixic acid (53.3%) related to MDR phenotype in 63.3% of isolates. The presence of class 1 and 2 integrons was 30% and 6.6% with the dominance of dfrA, aadA gene cassettes among the isolates. Eleven out of 21 phenotypically tetracycline-resistant isolates (52.38%) harboured one or two tetracycline resistance genes (A-D) which shows the incapability of known data to reasonable tetracycline resistance phenotypes among EPEC isolates. A high level of genotypic diversity was seen among the isolates by Pulsed-field gel electrophoresis method which ranged from 89.7 to 29% and no clear correlation was obtained between tetracycline resistance or integron carriage and specific pulsotypes. In conclusion, the data presented here add to knowledge about the heterogeneous nature of MDR EPEC population in Iran which has a growing tendency towards atypical genotypes. The distribution of integrons among EPEC isolates in Iran is decreasing; although, the resistance gene content is almost stable through years.

Gastroenteritis attributable to 16 enteropathogens in children attending day care: significant effects of rotavirus, norovirus, astrovirus, Cryptosporidium and Giardia

BACKGROUND

Children attending day care experience substantial gastrointestinal morbidity due to circulating seasonal enteropathogens in the day-care environment. The lack of a distinct clinical presentation of gastroenteritis (GE) in these children, in combination with the high diversity of enteropathogenic agents, complicates the assessment of the individual contributions of enteropathogens that may cause GE. We aimed to estimate the proportion of day-care attendees experiencing GE that could be attributed to a range of enteropathogens circulating in day care in the Netherlands in 2010-2013.

METHODS

Using time-series data from a national laboratory-based and syndrome-based surveillance system in Dutch day-care centers and generalized estimating equation analysis, we modelled the variation in prevalence of 16 enteropathogens of bacterial (8), viral (5) and parasitic origin (3) circulating in day care to the variation of GE incidence among children attending day care.

RESULTS

Rotavirus, norovirus, astrovirus, Giardia and Cryptosporidium were significantly associated with GE morbidity among day-care attendees in our time-series analysis. Together, these enteropathogens accounted for 39% of the GE morbidity: 11% by rotavirus, 10% by norovirus, 8% by Giardia, 7% by astrovirus and 3% by Cryptosporidium.

CONCLUSIONS

We demonstrate that circulating viruses and parasites, rather than bacteria, contribute to seasonal GE experienced by children in day care.

Screening for faecal contamination in primary schools in Crete, Greece

BACKGROUND

Hygienic conditions in primary schools are a major concern for both governmental organizations and families. Particularly, the occurrence of faecal indicators on children's hands and various school surfaces has been associated with increased risk of diarrhoeal diseases. The presence of faecal streptococci on environmental surfaces and children's hands and the possible correlation with socio-economic factors were examined.

METHODS

Overall, 1956 samples from hands and 1470 samples from surfaces were collected from 20 primary schools in Heraklion, Crete, Greece.

RESULTS

Faecal streptococci were found at 52.9% of children's hands and at 16.7% of other surfaces. Children, who had parents with the highest education level (>12 years), had the lowest percentage (48.8%) of faecal contamination on their hands. Furthermore, boys exhibited higher levels of hands contamination compared with girls. Among the environmental surfaces examined, the school canteen reception was the most contaminated area.

CONCLUSION

High faecal contamination was detected in primary schools in the examined region. Children's hands were highly infected (52.9%), while boys exhibited higher levels of contamination. The educational level of parents correlated well with the contamination of children's hands.

Bacterial gut infections

Infections of the bowel as a result of bacterial enteropathogens are one of the most common medical problems. The use of novel molecular biology techniques and the recent development of new antimicrobial drugs and vaccines are helping us to identify, understand, treat and prevent these infections.

Enteroaggregative Escherichia coli Is a Cause of Acute Diarrheal Illness: A Meta-Analysis

BACKGROUND

Conflicting studies exist regarding the role of enteroaggregative Escherichia coli (EAEC) as a cause of acute diarrheal illness. The objective of this meta-analysis was to determine whether identification of EAEC in stool samples is associated with acute diarrheal illness among different subpopulations, by geographic area.

METHODS

A comprehensive search of electronic bibliographic databases (Medline and PubMed) from August 1985 to January 2006, as well as a search of conference proceedings, references of articles, and contacts with investigators of EAEC, yielded 354 studies.

RESULTS

Forty-one studies (12%) that met the selection criteria (i.e., that examined the association between acute diarrheal illness and the excretion of EAEC among different subpopulations) were included. In this meta-analysis, presence of EAEC identified with the HEp-2 cell adherence assay was found to be significantly associated with acute diarrheal illness among children residing in developing regions (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.36-1.83) and industrialized regions (OR, 1.23; 95% CI, 1.03-1.48), adults with human immunodeficiency virus infection residing in developing regions (OR, 6.43; 95% CI, 2.91-14.16), adults residing in developing regions (OR, 7.15; 95% CI, 1.96-26.04), and international travelers to developing regions (OR, 6.72; 95% CI, 2.62-17.20). A limited number of studies were available that examined the role of EAEC identified by its virulence genes by a DNA probe.

CONCLUSIONS

On the basis of this meta-analysis, we conclude that EAEC is a cause of acute diarrheal illness among many different subpopulations in both developing and industrialized regions, that EAEC strains are very heterogeneous and that additional studies that examine the role of EAEC in acute diarrheal illness are needed.

Detection of enteroaggregative Escherichia coli with formalin-preserved HEp-2 cells

Formalin-stored HEp-2 cells were used to assay Escherichia coli for adherence. Cells refrigerated in formalin for up to 28 days and used in a wet assay format demonstrated an assay sensitivity ranging from 94 to 98% to detect enteroaggregative E. coli (EAEC). HEp-2 cells first fixed and stored with formalin and then stored dry in ambient conditions for 6 weeks demonstrated an assay sensitivity of 92% to detect EAEC. Using formalin-fixed HEp-2 cells will improve the efficiency of EAEC identification.

Enteroaggregative Escherichia coli

Enteroaggregative Escherichia coli (EAEC) are an increasingly important cause of diarrhoea. E. coli belonging to this category cause watery diarrhoea, which is often persistent and can be inflammatory. EAEC have been implicated in sporadic diarrhoea in children and adults, in both developing and developed countries, and have been identified as the cause of several outbreaks worldwide. EAEC are defined by their ability to adhere to epithelial cells in a characteristic "stacked-brick" pattern but are otherwise highly heterogeneous. Genes that could contribute to the pathogenicity of EAEC encode adhesins, toxins, and other factors, all of which are only partially conserved. Practicable tools are needed to improve diagnosis and identify risk factors. EAEC-infected individuals can be treated with fluoroquinolones but there is a need to examine alternative treatment protocols.

Gastrointestinal infections in children

New pathogens that cause gastroenteritis in children are being recognized. Even well-recognized pathogens, such as Clostridium difficile, may require more extensive testing than was previously thought necessary. Several new tests have emerged that allow for faster identification of these pathogens so that same-day results may be possible. Probiotic therapy has emerged as a novel strategy for the treatment of gastroenteritis. New vaccines against both viral and bacterial causes of gastroenteritis are being developed. The most exciting recent advance in vaccine development may be the creation of edible vaccines.