Characterization of Enteroaggregative Escherichia Coli Among Diarrheal Childrenin Western Brazilian Amazon

Abstract

BACKGROUND: Enteroaggregative Escherichia coli (EAEC) is one of the main acute and chronic diarrhea causes both in children and adults, mainly in developing countries. OBJECTIVE: The aim of the present study is to characterize EAEC strains isolated from faecal samples and to identify genes potentially contributing to virulence, biofilm production and antimicrobial resistance in children admitted to a pediatric hospital in Porto Velho, Rondônia State. METHODS: The total of 1,625 E. coli specimens were isolated from 591 children in the age group 6 years or younger who were hospitalized in Cosme and Damião Children Hospital in Porto Velho, between February 2010 and February 2012, with acute gastroenteritis. Colonies suggestive of E. coli were subjected to polymerase chain reaction testing in order to identify the virulence factors. The in vitro adhesion assays using HEp-2 adherence were tests. Biofilm detection through spectrophotometry and antimicrobial susceptibility tests were conducted in the disk diffusion method. RESULTS: The mentioned study examined 591 stool samples from children with diarrhea. Diarrheogenic E. coli was found in 27.4% (162/591) of the children. EAEC was the diarreagenic E. coli most frequently associated with diarrhea 52.4% (85/162), which was followed by enteropathogenic E. coli 43.8% (71/162), enterotoxigenic E. coli 2.4% (4/162), and enterohemorrhagic E. coli 1.2% (2/162). The aggR gene was detected in 63.5% (54/85) of EAEC isolates; moreover, statistically significant correlation was observed among typical EAEC (aggR) and aatA (P<0.0001), irp2 (P=0.0357) and shf (P=0.0328). It was recorded that 69% (59/85) of the 85 analyzed EAEC strains were biofilm producers; 73% (43/59) of the biofilm producers carried the aggR gene versus 42.3% (11/26) of non-producers (P=0.0135). In addition, there was association between the aatA gene and biofilm production; 61% (36/59) of the samples presented producer strains, versus 19.2% (5/26) of non-producers (P<0.0004). Antibiotic sensitivity test evidenced that most EAEC were ampicillin 70.6% (60/85), sulfamethoxazole 60% (51/85), tetracycline 44.7% (38/85) and cefotaxime 22.4% (19/85) resistant. CONCLUSION: As far as it is known, the present study is pioneer in Northern Brazil to investigate EAEC virulence factors and to show the antimicrobial susceptibility of EAEC strains isolated from children with diarrhea.

Analysis of the Virulence Profile and Phenotypic Features of Typical and Atypical Enteroaggregative Escherichia coli (EAEC) Isolated From Diarrheal Patients in Brazil

“…Several of the virulence factor-encoding genes investigated here were statistically more frequent among typical EAEC, which is not surprising since the majority of these genes were identified, and functionally characterized, in the typical EAEC prototype strain 042 (Harrington et al, 2006;Chaudhuri et al, 2010;Hebbelstrup Jensen et al, 2014). Similar findings were also observed by other Brazilian authors that compared typical and atypical EAEC isolates, especially with the pic, aap, shf, and agg4A genes being more frequent among the typical EAEC isolates (Andrade et al, 2017;Taborda et al, 2018;Guerrieri et al, 2019). Case-control studies, performed in distinct geographic regions, have been able to demonstrate the association of some genes encoding virulence factors with diarrheal disease.…”

Molecular Epidemiology of Enteroaggregative Escherichia coli (EAEC) Isolates of Hospitalized Children from Bolivia Reveal High Heterogeneity and Multidrug-Resistance

“…The prevalence of the a-EAEC was surprisingly higher and significantly associated with diarrhea compared with t-EAEC and non-diarrheal EAEC isolates. The majority of the epidemiological studies have reported t-EAEC isolates as the predominant subtype of EAEC isolated associated with the disease (6,32,45,48), while other studies have not been able to associate t-EAEC (AggR-positive) with diarrhea (19,49,50). Therefore the association of aggR-positive strains and diarrhea is not consistent.…”

Pandemic ST131Escherichia colipresenting the UPEC/EAEC and ExPEC/EAEC hybrid pathotypes recovered from extraintestinal infections in a clinical setting of the Brazilian Amazon region

“…However, there is a lack of association concerning the STs of such hybrid strains circulating in the country. Moreover, most of these reports on hybrid strains were restricted to São Paulo, a cosmopolitan city of the Southeast Brazilian region, and until now, all studies reporting E. coli infections in the Amazon Region were associated only with diarrheagenic infections [19][20][21][22]. Therefore, further studies are required to investigate the distribution and potential impact of these strains on the clinical outcomes of affected individuals.…”