Enteroaggregative Escherichia coli in Daycare-A 1-Year Dynamic Cohort Study

Enteroaggregative Escherichia coli in mid-Norway: A prospective, case control study

BACKGROUND

The use of molecular methods has led to increased detection of Enteroaggregative Escherichia coli (EAEC) in faecal samples. Studies have yielded conflicting results regarding the clinical relevance of this finding. The objective of this study was to investigate the prevalence of EAEC in faecal samples from patients with diarrhoea and healthy controls and describe characteristics of EAEC positive persons.

METHODS

From March 1st, 2017 to February 28th, 2019, we investigated all consecutive faecal samples from patients with diarrhoea received at the laboratory and collected faecal samples from randomly invited healthy controls from mid-Norway. Real-time multiplex PCR was used for detection of bacterial, viral, and parasitic pathogens. We registered sex, age, urban versus non-urban residency, and travel history for all participants. Statistical analyses were performed with Pearson chi-squared test, Kruskal-Wallis test, and Mann-Whitney U test.

RESULTS

We identified EAEC in 440 of 9487 (4.6%) patients with diarrhoea and 8 of 375 (2.2%) healthy controls. The EAEC prevalence was 19.1% among those with diarrhoea and recent foreign travel and 2.2% in those without travel history independent of diarrhoea. Concomitant pathogens were detected in 64.3% of EAEC-positive patients with diarrhoea. The median age was 28.5 in those with EAEC-positive diarrhoea and 38 in those with EAEC-negative diarrhoea (p <0.01). In patients with diarrhoea, travel was reported in 72% of those with EAEC and concomitant pathogens, and 54% and 12% in those with only EAEC and no EAEC, respectively (p <0.01).

CONCLUSIONS

EAEC was a common detection, particularly in patients with diarrhoea and recent international travel, and was found together with other intestinal pathogens in the majority of cases. Our results suggest that domestically acquired EAEC is not associated with diarrhoea. Patients with EAEC-positive diarrhoea and concomitant pathogens were young and often reported recent travel history compared to other patients with diarrhoea.

Enteroaggregative Escherichia coli as etiological agent of endemic diarrhea in Spain: A prospective multicenter prevalence study with molecular characterization of isolates

Background

Enteroaggregative Escherichia coli (EAEC) is increasingly associated with domestically acquired diarrheal episodes in high-income countries, particularly among children. However, its specific role in endemic diarrhea in this setting remains under-recognized and information on molecular characteristics of such EAEC strains is limited. We aimed to investigate the occurrence of EAEC in patients with non-travel related diarrhea in Spain and molecularly characterize EAEC strains associated with illness acquired in this high-income setting.

Methods

In a prospective multicenter study, stool samples from diarrheal patients with no history of recent travel abroad (n = 1,769) were collected and processed for detection of EAEC and other diarrheagenic E. coli (DEC) pathotypes by PCR. An additional case–control study was conducted among children ≤5 years old. Whole-genome sequences (WGS) of the resulting EAEC isolates were obtained.

Results

Detection of DEC in the study population. DEC was detected in 23.2% of patients aged from 0 to 102 years, with EAEC being one of the most prevalent pathotypes (7.8%) and found in significantly more patients ≤5 years old (9.8% vs. 3.4%, p &lt; 0.001). Although not statistically significant, EAEC was more frequent in cases than in controls. WGS-derived characterization of EAEC isolates. Sequence type (ST) 34, ST200, ST40, and ST10 were the predominant STs. O126:H27, O111:H21, and O92:H33 were the predominant serogenotypes. Evidence of a known variant of aggregative adherence fimbriae (AAF) was found in 89.2% of isolates, with AAF/V being the most frequent. Ten percent of isolates were additionally classified as presumptive extraintestinal pathogenic E. coli (ExPEC), uropathogenic E. coli (UPEC), or both, and belonged to clonal lineages that could be specifically associated with extraintestinal infections.

Conclusion

EAEC was the only bacterial enteric pathogen detected in a significant proportion of cases of endemic diarrhea in Spain, especially in children ≤5 years old. In particular, O126:H27-ST200, O111:H21-ST40, and O92:H33-ST34 were the most important subtypes, with all of them infecting both patients and asymptomatic individuals. Apart from this role as an enteric pathogen, a subset of these domestically acquired EAEC strains revealed an additional urinary/systemic pathogenic potential.

Identification of a hybrid atypical enteropathogenic and enteroaggregative Escherichia coli (aEPEC/EAEC) clone of serotype O3:H2 associated with a diarrheal outbreak in Brazil

Enteropathogenic (EPEC) and enteroaggregative (EAEC) Escherichia coli are two of the major pathotypes of diarrheagenic E. coli causing disease worldwide. Here, we report a diarrheal outbreak caused by E. coli of serotype O3:H2, harboring virulence markers from EPEC (eae) and/or EAEC (aggR). This is likely the first E. coli diarrheal outbreak caused by a hybrid atypical-EPEC/EAEC clone reported in Brazil.

Mapping of aetiologies of gastroenteritis: a systematic review and meta-analysis of pathogens identified using a multiplex screening array

OBJECTIVE

Emergence of molecular methods to screen stools could provide a more complete picture of pathogens causing gastroenteritis, allowing to adequately treat patients whenever required but, so far, no aggregate data have been released. Our objective was to report pathogens identified in patients suffering from gastroenteritis using a multiplex molecular array.

DESIGN

Medline and Embase were searched for original publications reporting pathogens identified with FilmArray GI panel in patients suffering from gastroenteritis. Proportions of pathogens were extracted and pooled using a model with random effects.

RESULTS

Fourteen studies (17,815 patients) were included in the analysis. Among the 7,071 patients (39.7%) with positive FilmArray, identified pathogens were EPEC (27.5%), Clostridium difficile (19.3%), Norovirus (15.1%), EAEC (15%), Campylobacter spp (11.8%), Salmonella spp (8.1%), ETEC (7.3%), Rotavirus (7.3%), Sapovirus (7.1%), STEC (5.2%), Shigella/EIEC (4.9%), Giardia lamblia (4%), Adenovirus (3.8%), Cryptosporidium spp (3.8%), Astrovirus (2.8%), Yersinia enterocolitica (1.7%), Escherichia coli O157 (1.1%), Plesiomonas shigelloides (1.1%), Cyclospora cayetanensis (0.7%), Vibrio spp (0.5%), Vibrio cholerae (0.3%) and Entamoeba histolytica (0.3%). When considering only studies with control group (microbiological examination of the stools performed by other methods), FilmArray identified at least one pathogen in 48.2% of patients versus 16.7% when using comparative diagnostic methods.

CONCLUSIONS

FilmArray GI panel was positive in 39.7% of patients suffering from gastroenteritis. This proportion has to be mitigated by the carriage rates of identified organisms. Ultimately, restricted ordering of molecular panels to those patients who might benefit from specific treatment could provide medical value by swift identification of the pathogen and more targeted therapy.

Mixed Aetiology of Diarrhoea in Infants Attending Clinics in the North-West Province of South Africa: Potential for Sub-Optimal Treatment

Routine diagnostic methods for the aetiologic agents of diarrhoea in most developing countries are usually not sensitive enough, leading to under-diagnosis. Thus, this study investigated possible mixed diarrhoeal aetiology by using cultures and real-time polymerase chain reactions (PCR) in children younger than four years old in the Northwest Province, South Africa. In total, 505 stool samples were collected from symptomatic and asymptomatic children who were attending three clinics and the Brits hospital in Madibeng District, between September 2016 and December 2017. Rotavirus, norovirus, Campylobacter, Arcobacter, and diarrhoeagenic Escherichia coli (DEC) were targeted. Campylobacter spp. (24.6%), Arcobacter (15.8%) and DEC (19.6%) were detected using PCR; only Campylobacter spp. (29.7%) and DEC (26.9%) were detected through the culture. Campylobacter jejuni (36%), Campylobacter coli (28%), Campylobacter upsalensis (12%), and Arcobacter butzleri (15.8%) were the only spp. of Campylobacter and Arcobacter identified. The eaeA gene (31.4%) of enteropathogenic E. coli/enterohaemorrhagic E. coli (EPEC/EHEC) was the most prevalent DEC virulence gene (VG) identified. Rotavirus and norovirus were detected at 23.4% and 20%, respectively. Mixed viral aetiology (7.3%) and the co-infection of A. butzleri and Campylobacter (49%) were recorded. A mixed bacterial-viral aetiology was observed in 0.6% of the specimens. Sensitive diagnostic procedures like PCR should be considered to provide the best treatment to children experiencing diarrhoea.

Children Attending Day Care Centers are a Year-round Reservoir of Gastrointestinal Viruses

Viral gastroenteritis causes high morbidity worldwide. In this study, stool samples from 179 children aged 0–6 years attending Danish day care centers were investigated for gastrointestinal viruses. Each child was observed for one year with submission of samples and questionnaires every two months. Adenovirus, norovirus, rotavirus, and sapovirus were detected in samples using real-time PCR. A total of 229 (33%) of the 688 samples collected tested positive for at least one virus. At the first sampling point, adenovirus was shed by 6%, norovirus genotype I by 3% and genotype II by 12%, rotavirus A by 9%, and sapovirus by 21% of the 142 children included in the risk factor analyses. Increasing age was identified as a protective factor against testing positive for gastrointestinal virus, whereas nausea during the previous two months was positively associated with testing positive. Odds of shedding adenovirus were 9.6 times higher among children treated with antibiotics within the previous two months than among children who were not. Gastrointestinal viruses were shed year-round and high viral loads were observed in samples from both symptomatic and asymptomatic children, suggesting children in day care as a reservoir and a possible source of spreading of viruses into the community.

Stability and resilience of the intestinal microbiota in children in daycare - a 12 month cohort study

BACKGROUND

We performed a 12-month cohort study of the stability and resilience of the intestinal microbiota of healthy children in daycare in Denmark in relation to diarrheal events and exposure to known risk factors for gastrointestinal health such as travelling and antibiotic use. In addition, we analyzed how gut microbiota recover from such exposures.

RESULTS

We monitored 32 children in daycare aged 1-6 years. Fecal samples were submitted every second month during a one-year observational period. Information regarding exposures and diarrheal episodes was obtained through questionnaires. Bacterial communities were identified using 16S rRNA gene sequencing. The core microbiota (mean abundance > 95%) dominated the intestinal microbiota, and none of the tested exposures (diarrheal events, travel, antibiotic use) were associated with decreases in the relative abundance of the core microbiota. Samples exhibited lower intra-individual variation than inter-individual variation. Half of all the variation between samples was explained by which child a sample originated from. Age explained 7.6-9.6% of the variation, while traveling, diarrheal events, and antibiotic use explained minor parts of the beta diversity. We found an age-dependent increase of alpha diversity in children aged 1-3 years, and while diarrheal events caused a decrease in alpha diversity, a recovery time of 40-45 days was observed. Among children having had a diarrheal event, we observed a 10x higher relative abundance of Prevotella. After travelling, a higher abundance of two Bacteroides species and 40% less Lachnospiraceae were seen. Antibiotic use did not correlate with changes in the abundance of any bacteria.

CONCLUSION

We present data showing that Danish children in daycare have stable intestinal microbiota, resilient to the exposures investigated. An early age-dependent increase in the diversity was demonstrated. Diarrheal episodes decreased alpha diversity with an estimated recovery time of 40-45 days.

Characterization of Diarrheagenic Enteroaggregative Escherichia coli in Danish Adults-Antibiotic Treatment Does Not Reduce Duration of Diarrhea

Enteroaggregative Escherichia coli (EAEC) is frequently isolated from sporadic cases of diarrhea and in outbreaks of gastroenteritis in several regions of the world. The pathophysiology of EAEC continues to be enigmatic, and the efficacy of antibiotic treatment in EAEC-associated diarrhea has been discussed. Since the level of antibiotic resistance is increasing, it is essential to restrict the use of antibiotics to prevent further resistance development. We aimed to investigate EAEC strains in adult Danish patients suffering from diarrhea and from healthy controls. We examined the antibiotic resistance in EAEC strains, the clinical response to antibiotic treatment in EAEC diarrheal cases, and the distribution of virulence genes in diarrheal cases. The EAEC strains were collected from patients suffering from diarrhea in a Danish multicenter study. A medical doctor interviewed the patients by using a questionnaire regarding gastrointestinal symptoms, exposures, and use of antibiotic and over-the-counter antidiarrheal drugs. Follow-up was performed after 3–5 months to inquire about differential diagnosis to gastrointestinal disease. A multiplex polymerase chain reaction characterized virulence genes in diarrheal cases. Finally, the level of antibiotic resistance was examined by using the disc diffusion method. Asymptomatic carriage of EAEC in the adult Danish population was rare, in contrast to findings in healthy Danish children. The duration of diarrhea was not shortened by antibiotic treatment, specifically ciprofloxacin treatment, or by over-the-counter antidiarrheal drugs. Follow-up revealed no pathology in diarrheal patients apart from irritable bowel syndrome in two patients. A high number of patients suffered from long-term diarrhea, which was associated with the enterotoxin EAST-1 and a high virulence factor score. A high level of antibiotic resistance was observed and 58% of the EAEC strains were multidrug resistant. Multidrug resistance was most pronounced in cases of travelers' diarrhea, and it was seen that antibiotic treatment did not reduce the duration of diarrhea.

Genetic Virulence Profile of Enteroaggregative Escherichia coli Strains Isolated from Danish Children with Either Acute or Persistent Diarrhea

Enteroaggregative Escherichia coli (EAEC) is frequently found in diarrheal stools worldwide. It has been associated with persistent diarrhea, weight loss, and failure to thrive in children living in developing countries. A number of important EAEC virulence genes are identified; however, their roles in acute and persistent diarrhea have not been previously investigated. The aim of this study was to identify specific EAEC virulence genes associated with duration and type of diarrhea in Danish children. We aimed to improve the current diagnostics of EAEC and enable targeting of strains with an expected severe disease course. Questionnaires answered by parents provided information regarding duration of diarrhea and presence of blood or mucus. A total of 295 EAEC strains were collected from children with acute (≤7 days) and persistent diarrhea (≥14 days) and were compared by using multiplex PCR targeting the genes sat, sepA, pic, sigA, pet, astA, aatA, aggR, aaiC, aap, agg3/4C, ORF3, aafA, aggA, agg3A, agg4A, and agg5A. Furthermore, the distribution of EAEC genes in strains collected from cases of bloody, mucoid, and watery diarrhea was investigated. The classification and regression tree analysis (CART) was applied to investigate the relationship between EAEC virulence genes and diarrheal duration and type. Persistent diarrhea was associated with strains lacking the pic gene (p = 0.002) and with the combination of the genes pic, sat, and absence of the aggA gene (p = 0.05). Prolonged diarrhea was associated with the combination of the genes aatA and astA (p = 0.03). Non-mucoid diarrhea was associated with strains lacking the aatA gene (p = 0.004). Acute diarrhea was associated with the genes aggR, aap, and aggA by individual odds ratios. Resistance toward gentamicin and ciprofloxacin was observed in 7.5 and 3% of strains, respectively. Multi-drug resistance was observed in 38% of strains. Genetic host factors have been associated with an increased risk of EAEC-associated disease. Therefore, we investigated a panel of risk factors in two groups of children—EAEC-positive and EAEC-negative—to identify additional factors predisposing to disease. The duration of breastfeeding was positively correlated with the likelihood of belonging to the EAEC-negative group of children.

Dientamoeba fragilis, a Commensal in Children in Danish Day Care Centers

Dientamoeba fragilis is an intestinal protozoan of debated clinical significance. Here, we present cross-sectional and longitudinal observations on D. fragilis in children aged 0 to 6 years from a 1-year multi-day-care-center cohort study set in Copenhagen, Denmark. The inclusion period for the cohort was 2009 through 2012. Stool samples collected from the children were accompanied by questionnaires completed by the parents or guardians of the children. Using real-time PCR, D. fragilis was detected in the first stool sample from 97 of 142 (68.3%) children. We evaluated the associations between seven plausible risk factors (age, sex, having siblings, having domestic animals at home, having had infant colic, recent history of intake of antibiotics, and recent history of travel abroad) as well as six reported symptoms (lack of appetite, nausea, vomiting, abdominal pain, weight loss, and diarrhea) and testing positive for D. fragilis The final multivariable model identified being >3 years old and having a history of recent travel abroad as risk factors for testing positive for D. fragilis Moreover, univariable analyses indicated that having siblings was a risk factor. There was no statistical association between a recent history of gastrointestinal symptoms and testing positive for D. fragilis Among the 108 children who were represented by ≥2 samples and thus included in the longitudinal analysis, 32 tested negative on the first sample and positive later, and the last sample from each of the 108 children was positive. The results are in support of D. fragilis being a common enteric commensal in this population.