Typical Enteropathogenic Escherichia Coli Research Articles

Characterisation of typical enteropathogenic Escherichia coli (tEPEC) lineages and novel bfpA variants detected in Australian fruit bats (Pteropus poliocephalus)

Enteropathogenic Escherichia coli (EPEC) is an important cause of diarrhoeal disease in human infants. EPEC strains are defined by the presence of specific virulence factors including intimin (encoded by the eae gene) and bundle forming pili (Bfp). Bfp is encoded by the bfp operon and includes the bfpA gene for the major pilus subunit. By definition, Bfp are only present in typical EPEC (tEPEC), for which, humans are considered to be the only known natural host. This study detected tEPEC in faecal samples from a wild Australian fruit bat species, the grey-headed flying-fox (Pteropus poliocephalus). Whole genome sequencing of 61 E. coli isolates from flying-foxes revealed that 21.3 % (95%CI: 13 %–33 %) were tEPEC. Phylogenetic analyses showed flying-fox tEPEC shared evolutionary lineages with human EPEC, but were predominantly novel sequence types (9 of 13) and typically harboured novel bfpA variants (11 of 13). HEp-2 cell adhesion assays showed adherence to human-derived epithelial cells by all 13 flying-fox tEPEC, indicating that they all carried functional Bfp. Using an EPEC-specific duplex PCR, it was determined that tEPEC comprised 17.4 % (95%CI: 13 %–22 %) of 270 flying-fox E. coli isolates. Furthermore, a tEPEC-specific multiplex PCR detected the eae and bfpA virulence genes in 18.0 % (95%CI: 8.0 %–33.7 %) of 506 flying-fox faecal DNA samples, with occurrences ranging from 1.3 % to 87.0 % across five geographic areas sampled over a four-year period. The identification of six novel tEPEC sequence types and five novel bfpA variants suggests flying-foxes carry bat-specific tEPEC lineages. However, their close relationship with human EPEC and functional Bfp, indicates that flying-fox tEPEC have zoonotic potential and that dissemination of flying-fox tEPEC into urban environments may pose a public health risk. The consistent detection of tEPEC in flying-foxes over extensive geographical and temporal scales indicates that both wild grey-headed flying-foxes and humans should be regarded as natural tEPEC hosts.

Epidemiology of Enteroaggregative, Enteropathogenic, and Shiga Toxin–ProducingEscherichia coliAmong Children Aged <5 Years in 3 Countries in Africa, 2015–2018: Vaccine Impact on Diarrhea in Africa (VIDA) Study

To address knowledge gaps regarding diarrheagenic Escherichia coli (DEC) in Africa, we assessed the clinical and epidemiological features of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), and Shiga toxin-producing E. coli (STEC) positive children with moderate-to-severe diarrhea (MSD) in Mali, The Gambia, and Kenya. Between May 2015 and July 2018, children aged 0-59 months with medically attended MSD and matched controls without diarrhea were enrolled. Stools were tested conventionally using culture and multiplex polymerase chain reaction (PCR), and by quantitative PCR (qPCR). We assessed DEC detection by site, age, clinical characteristics, and enteric coinfection. Among 4840 children with MSD and 6213 matched controls enrolled, 4836 cases and 1 control per case were tested using qPCR. Of the DEC detected with TAC, 61.1% were EAEC, 25.3% atypical EPEC (aEPEC), 22.4% typical EPEC (tEPEC), and 7.2% STEC. Detection was higher in controls than in MSD cases for EAEC (63.9% vs 58.3%, P < .01), aEPEC (27.3% vs 23.3%, P < .01), and STEC (9.3% vs 5.1%, P < .01). EAEC and tEPEC were more frequent in children aged <23 months, aEPEC was similar across age strata, and STEC increased with age. No association between nutritional status at follow-up and DEC pathotypes was found. DEC coinfection with Shigella/enteroinvasive E. coli was more common among cases (P < .01). No significant association was detected between EAEC, tEPEC, aEPEC, or STEC and MSD using either conventional assay or TAC. Genomic analysis may provide a better definition of the virulence factors associated with diarrheal disease.

Pathophysiology of Enteropathogenic Escherichia coli-induced Diarrhea.

Enteropathogenic Escherichia coli (EPEC) are important diarrheal pathogens of infants and young children. Since the availability of molecular diagnosis methods, we now have new insights into the incidence and prevalence of these infections. Recent epidemiological studies indicate that atypical EPEC (aEPEC) are seen more frequently than typical EPEC (tEPEC) worldwide, including in both endemic diarrhea and diarrhea outbreaks. Therefore, it is important to further characterize the pathogenicity of these emerging strains. The virulence mechanisms and pathophysiology of the attaching and effacing lesion (A/E) and the type-three-secretion-system (T3SS) are complex but well-studied. A/E strains use their pool of locus of enterocyte effacement (LEE)-encoded and non-LEE-encoded effector proteins to subvert and modulate cellular and barrier properties of the host. However, the exact mechanisms of diarrhea in EPEC infection are not completely understood. From the clinical perspective, there is a need for fast, easy, and inexpensive diagnostic methods to define optimal treatment and prevention for children in endemic areas. In this article, we present a review of the classification of EPEC, epidemiology, pathogenesis of the disease caused by these bacteria, determinants of virulence, alterations in signaling, determinants of colonization vs. those of disease, and the limited information we have on the pathophysiology of EPEC-induced diarrhea. This article combines peer-reviewed evidence from our own studies and the results of an extensive literature search in the databases PubMed, EMBASE, and Scopus.

Molecular genotyping of Escherichia coli o111 isolated from children with diarrhea in rural and urban areas

Introduction: Enteropathogenic Escherichia coli (EPEC) is a group of bacteria associated with infantile diarrhea. EPEC is defined as being typical (tEPEC) or atypical (aEPEC) depending on whether it presents the EPEC adherence factor (EAF) plasmid or not; tEPEC presents EAF. Objective. Carry out a retrospective study of E. coli strains isolated from children with diarrhea in both rural and urban areas to determine if they belong to tEPEC or aEPEC groups. Material &amp; Methods: Strains that had been reported to be E. coli were analyzed by PCR using specific primers and 188 anti-O sera and 53 anti-H sera. The presence of eae, bfp, eafA, perA, espC and espP genes associated with virulence was analyzed, as was the presence of arpA, chuA, yjaA and TspE4 to define phylogroups. Results: Fifty-three cultures of E. coli isolated between 1985 and 2003 from 35 children under five years of age with severe diarrhea were analyzed. Twelve (34.3%) children came from a rural area and 23 (65.7%) from an urban area. Serologic typing identified the following serotypes: O111ab:NM (67.9%), O111ab:H2 (20.8%), O111ab:H12 (9.4%) and O111ac:H8 (1.9%). The presence of eae was positive in all 53 strains, while bfp and perA was detected in 38 (71.7%) strains and eaf in 35 (66%) strains. The combination of eae/bfp used to determine typical strains was positive in 38 (71.7%) strains and negative in 15 (28.3%) strains. Analysis by year and region showed that between 1985 and 1987, 35 (66%) strains were typical and 4 (7%) atypical in the rural area and urban area1. The same analysis between 1994 and 2003 in the urban areas showed that 11 (20.8%) strains were atypical, which were eae positive but eaf/bfp/perA negative, and 3 (5.7%) strains were typical. Phylogenetic grouping identified B1 and A in 38 (71.7%) and 9 (17%) strains respectively, and 2 (3.8%) each of B2, D and F. Conclusion. Typical EPEC strains were more prevalent in both the rural and urban areas between 1985 and 1987. In contrast, the presence of atypical EPEC strains was more prevalent in urban areas in more recent years. Analysis showed that the strains fell predominantly into commensal phylogroups.

Molecular analysis of enteropathogenic Escherichia coli (EPEC) isolates from healthy food-producing animals and humans with diarrhoea.

Enteropathogenic Escherichia coli (EPEC) is a pathogen associated with acute diarrhoea in humans. To determine whether EPEC isolated from healthy food-producing animals possesses the same virulence gene repertoire as EPEC isolated from human with diarrhoea, we compared six typical EPEC (tEPEC) and 20 atypical EPEC (aEPEC) from humans with diarrhoea and 42 aEPEC from healthy animals (swine, sheep and buffaloes), using pulsed-field gel electrophoresis (PFGE), virulence markers, serotyping and subtyping of eae and tir genes. We found that human and animal isolates shared virulence genes, including nleB, nleE and nleF, which were associated with human diarrhoea. Serogroups and serotypes identified in isolates of food-producing animals such as O26:H11, O128:H2, O76:H7, O103, O108, O111 and O145, have previously been implicated in human disease. The subtypes eae and tir were also shared between human and animal isolates, being eae-γ1 and eae-β1 the most prevalent in both groups, while the most common tir subtypes were α and β. Despite PFGE analysis demonstrating that EPEC strains are heterogeneous and there was no prevalent clone identified, EPEC isolated from humans and food-producing animals shared some characteristics, such as virulence genes associated with human diarrhoea, indicating that food-producing animals could play a role as reservoirs for those genes.

Serotyping and prevalence of stx gene among E. coli isolates from HIV/AIDS patients with diarrhea; Shiraz, Iran

Background/aimDiarrhea is significant morbidity in individuals with HIV which is caused by a multitude of etiologies such as infectious agents, malignancies, and medications. This complication may reduce the quality of life and increase the mortality rate in the advanced form of this disease. Among infectious reasons, bacterial species such as Escherichia coli (E. coli) are the main causes of diarrhea. Enterohemorrhagic Escherichia coli (EHEC) species with the potential of Shiga toxin-producing can be the main cause of severe diarrhea and life-threatening HIV patients. Stx genes as the main factor and causative agent of Shiga toxin-producing in E. coli isolates can be pointed to determine the prevalence of EHEC is a diarrheal causative agent in HIV patients. MethodologyThis cross-sectional study was conducted from June 2019 to June 2020, which comprised 117 HIV-positive patients with diarrhea. Collected stool samples were evaluated for diarrheal bacteria (such as Shigella, salmonella, and E. coli) by standard phenotypic, serology, and conventional molecular techniques. ResultsE. coli was detected in 110 samples. Based on the distribution of virulence genes,25 (22.72%) isolates belonged to the enteropathogenic E. coli (EPEC) group 40% and 60% of these isolates were confirmed as typical and atypical EPEC, Respectively. 21(19.00%) isolates belonged to the enterohemorrhagic E. coli (EHEC) group, 5 (4.54%) to Shiga toxin-producing E. coli (STEC). While, 6 (30.00%) isolates carried Stx1, 10 (50.00%) Stx2 and 4 (20.00%) harbored both stx1 and stx2. ConclusionRelatively high prevalence of Shiga toxigenic E. coli isolates in studied HIV patients shows a threat of infectious agents as a cause of diarrhea in immunocompromised patients who must be careful about infectious control disciplines.

Characterization of shiga-toxin producing E.coli (STEC) and Enteropathogenic E. coli (EPEC) from domestic animals for virulence and colonisation factors and their antimicrobial resistance

Aim: To determine the occurrence and molecular characterization of Shiga toxin-producing E. coli (STEC) and Enteropathogenic E. coli (EPEC) from different domestic animals for serogrouping, virulence factors and their antibiotic resistance from Jammu region. Methodology: Faecal samples were collected from 200 different animals including calves (39), rabbits (24), dogs (38), slaughtered pigs (22), poultry (41), sheep and goat (36). All the 200 strains were screened for the presence of stx1, stx2 and eae genes by m-PCR and screening of confirmed EPEC isolates with respect to their serogroup, virulence factors (bfpA, astA and ecpA genes) by PCR and antibiotic resistance. Results: Of total 200 E. coli isolates, 38 (19.00%) were detected as EPEC and 28 (14.00%) as STEC. 5 (12.82%), 17 (43.58%) isolates from calves and 12 (33.33%), 11 (30.55%) isolates from sheep were found as EPEC and STEC, respectively. In rabbits, pigs and dogs, 6 (25.0%), 10 (45.45%) and 5 (13.15%) isolates were detected as EPEC, respectively. The most predominant EPEC serogroups were O88 (36.84%), O118 (18.42%). All 38 EPEC (100%) isolates carried ecpA gene and 18 (47.36%) isolates carried astA gene. Of 38 EPEC, only 5 (13.15%) isolates from dog carried bfpA gene, therefore considered as typical EPEC and 33 (86.84%) isolates were designated as atypical EPEC. Antimicrobial sensitivity test (AST) of 38 EPEC isolates showed resistance to nalidixic acid (55.26%), kanamycin (42.10%) followed by streptomycin (42.10%), doxycycline hydrochloride (28.94%), ciprofloxacin (13.15%), tetracycline (13.15%). Surprisingly, all the 38 isolates were sensitive to ampicillin.

Prevalence, phylogeny, and antimicrobial resistance of Escherichia coli pathotypes isolated from children less than 5\u2009years old with community acquired- diarrhea in Upper Egypt

BackgroundDiarrhoea, affecting children in developing countries, is mainly caused by diarrheagenic Escherichia coli (DEC). This study principally aimed to determine the prevalence of DEC pathotypes and Extended-spectrum β-lactamase (ESBL) genes isolated from children under 5 years old with diarrhea.MethodsA total of 320 diarrhoea stool samples were investigated. E. coli isolates were investigated for genes specific for enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC) and enterohemorrhagic E. coli (EHEC) using polymerase chain reaction (PCR). Furthermore, antimicrobial susceptibility testing, detection of antibiotic resistance-genes and phylogenetic typing were performed.ResultsOver all, DEC were isolated from 66/320 (20.6%) of the children with diarrhoea. EAEC was the predominant (47%), followed by typical EPEC (28.8%) and atypical EPEC (16.6%). Co-infection by EPEC and EAEC was detected in (7.6%) of isolates. However, ETEC, EIEC and EHEC were not detected. Phylogroup A (47%) and B2 (43.9%) were the predominant types. Multidrug-resistance (MDR) was found in 55% of DEC isolates. Extended-spectrum β-lactamase (ESBL) genes were detected in 24 isolates (24 blaTEM and 15 blaCTX-M-15). Only one isolate harbored AmpC β-lactamase gene (DHA gene).ConclusionThe study concluded that, EAEC and EPEC are important causative agents of diarrhoea in children under 5 years. MDR among DEC has the potential to be a big concern.

Typical and atypical enteropathogenic Escherichia coli in children with acute diarrhoea: Changing trend in East Delhi

BackgroundWorldwide around 2 million deaths occur every year due to diarrhoeal illnesses among children less than 5 years of age. Among diarrhoeagenic Escherichia coli, Enteropathogenic E. coli (EPEC) is highly prevalent in both community and hospital settings and is one of the main causes of persistent diarrhea in children in developing countries. EPEC remains underdiagnosed in India due to lack of conventional tools for identification. MethodsWe in this study investigated the prevalence and regional variation of EPEC in paediatric population suffering from diarrhoea in East Delhi, India. Two hundred stool samples were collected from children, aged between 0.5 and 5 years, with acute diarrhoea. E. coli were identified by conventional tests and PCR. ResultsWe observed 7% atypical EPEC (aEPEC) and 2.5% typical EPEC (tEPEC), with an overall 9.5% EPEC prevalence amongst total samples. E. coli phylogenetic group A was the predominant. The most common age group affected was 6–23 months with common symptoms being vomiting, watery diarrhoea and severe dehydration. High drug resistance pattern was observed in EPEC isolates. ConclusionThe study depicts a changing trend of aEPEC over tEPEC in children less than 5 years with diarrhoea, an emerging drug resistant enteropathogen and a public health concern demanding monitoring and surveillance.

The Complete Genome of the Atypical Enteropathogenic Escherichia coli Archetype Isolate E110019 Highlights a Role for Plasmids in Dissemination of the Type III Secreted Effector EspT.

Enteropathogenic Escherichia coli (EPEC) is a leading cause of moderate to severe diarrhea among young children in developing countries, and EPEC isolates can be subdivided into two groups. Typical EPEC (tEPEC) bacteria are characterized by the presence of both the locus of enterocyte effacement (LEE) and the plasmid-encoded bundle-forming pilus (BFP), which are involved in adherence and translocation of type III effectors into the host cells. Atypical EPEC (aEPEC) bacteria also contain the LEE but lack the BFP. In the current report, we describe the complete genome of outbreak-associated aEPEC isolate E110019, which carries four plasmids. Comparative genomic analysis demonstrated that the type III secreted effector EspT gene, an autotransporter gene, a hemolysin gene, and putative fimbrial genes are all carried on plasmids. Further investigation of 65 espT-containing E. coli genomes demonstrated that different espT alleles are associated with multiple plasmids that differ in their overall gene content from the E110019 espT-containing plasmid. EspT has been previously described with respect to its role in the ability of E110019 to invade host cells. While other type III secreted effectors of E. coli have been identified on insertion elements and prophages of the chromosome, we demonstrated in the current study that the espT gene is located on multiple unique plasmids. These findings highlight a role of plasmids in dissemination of a unique E. coli type III secreted effector that is involved in host invasion and severe diarrheal illness.

Antibiotic resistance and biofilm formation in children with Enteropathogenic Escherichia coli (EPEC) in Brazilian Amazon

Enteropathogenic Escherichia coli is an important causative agent of diarrhea in both developed and developing countries. We assessed the antibiotic resistance profile and the ability of 71 Enteropathogenic Escherichia coli (EPEC) isolates from children in the age group 6 years, or younger, to form biofilm. These children were hospitalized in Cosme and Damião Children Hospital in Porto Velho, Western Brazilian Amazon, between 2010 and 2012, with clinical symptoms of acute gastroenteritis. The highest frequency of atypical EPEC (aEPEC) isolates reached 83.1% (59/71). Most EPEC isolates presented Localized Adherence Like (LAL) pattern in HEp-2 cells (57.7% - 41/71). Biofilm production was observed in 33.8% (24/71) of EPEC isolates, and it means statistically significant association with shf gene (p = 0.0254). The highest antimicrobial resistance rates and a large number of multiresistant isolates 67.6% (48/71), regarded cefuroxime (CXM), ampicillin (AMP), trimethoprim-sulfamethoxazole (SXT) and tetracycline (TET), respectively, mainly in typical EPEC (tEPEC). Furthermore, 96% (68/71) of EPEC isolates in the present study were resistant to at least one antibiotic, whereas only 3 isolates were sensitive to all the tested drugs. Based on our findings, there was increased aEPEC identification. EPEC isolates showed high resistance rate; most strains showed multiresistance; thus, they work as warning about the continuous need of surveillance towards antimicrobial use. Besides, the ability of forming biofilm was evidenced by the EPEC isolates. This outcome is worrisome, since it is a natural resistance mechanism of bacteria.

Molecular epidemiology and antimicrobial resistance of diarrheagic Escherichia coli among children with acute diarrhea

Objective To learn the distribution, epidemiology and antimicrobial susceptibility of diarrheagenic Escherichia coli (DEC) isolated from patients with acute diarrhea among children less than 5 years old. Methods Totally 684 stool samples collected from Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology between August 1, 2015 and September 30, 2016 were tested by culture and identified the common pathogens. PCR was applied to detect the virulence genes of DEC. Meanwhile, serotyping of enteropathogenic E. coli (EPEC) was performed by slide agglutination tests for all the isolates of EPEC. An antimicrobial sensitivity test was performed using the agar dilution method. Results A total of 149 (21.7%) enteric bacteria pathogens were isolated from 684 specimens. DEC was found in 54 cases, ranked 2nd among the pathogenic bacteria. DEC tended to occur in summer/autumn periods. EPEC was the most frequent DEC genotype, accounted for 50% (27/54). Among EPEC, atypical EPEC was dominant, accounted for 77.8% (21/27) and typical EPEC only accounted for 22.2% (6/27). Followed by enteroaggregative E.coli 20.4% (11/54), enterotoxigenic E.coli 14.8% (8/54), enteroinvasive E. coli and Shiga toxin-producing E.coli 3.7% (2/54), 7.4% (4/54) cases were co-infected with more than one DEC genotypes. About 17/18 of suspicious DEC isolates can get the same genotypes by commercial multiplex PCR kit and single PCR test. Among the 27 EPEC strains, only 11(40.7%) strains can be detected by the slide agglutination serotyping method. More than 50% (27/54) of DEC isolates were resistant to conventional first-line antibiotics (ampicillin, trimethoprim-sulfamethoxazole) and cefazolin, cefuroxime, cefotaxime, but relatively low resistance to cefoxitin, amikacin, piperacillin/tazobactam, imipenem and meropenem. However, there was still a 9.2% (5/54) resistance rate to carbapenems. Conclusions DEC strains exhibited a high frequency of resistance to many antibiotics. Empirical antimicrobial therapy of severe DEC infection faces the challenge from the high resistance to ampicillin, trimethoprim-sulfamethoxazole. Even worse, some strains were resistant to relatively efficient drugs imipenem and meropenem. It is necessary to strengthen the epidemiological survey and antimicrobial resistance of DEC. Key words: Diarrhea; Escherichia coli; Virulence; Escherichia coli infections; Drug resistance, bacterial; Epidemiologic studies

Surveillance for enterotoxigenic & enteropathogenic Escherichia coli isolates from animal source foods in Northwest Iran.

Background & objectives:Diarrhoeagenic Escherichia coli strains are common agents of diarrhoea particularly in developing countries. Food products of animal origin are considered as common carriers of E. coli. This study was undertaken to identify enterotoxigenic Escherichia coli (ETEC) and enteropathogenic E. coli (EPEC) pathotypes in animal-source foods (ASF).Methods:A total of 222 ASF samples were investigated. Based on the culture and biochemical tests, 109 E. coli isolates were identified. Duplex-polymerase chain reaction assay was used to detect ETEC and EPEC. The target genes selected for each category were the lt and st for the ETEC, and eae and bfp for the EPEC isolates.Results:The occurrence of E. coli in dairy and meat products was 45 and 52.5 per cent, respectively. Among the E. coli isolates, two ETEC, one typical EPEC and three atypical EPEC were detected in meat samples, whereas only one typical EPEC and one atypical EPEC were detected in dairy samples.Interpretation & conclusions:Our results showed presence of ETEC and EPEC strains in ASFs. The milk without pasteurization and traditional dairy products produced in unhygienic conditions are most likely the main sources of E. coli pathotypes and other zoonotic pathogens and thus can be considered a potential hazard to the health of the community.

Captive wildlife from India as carriers of Shiga toxin-producing, Enteropathogenic and Enterotoxigenic &lt;i&gt;Escherichia coli&lt;/i&gt;

Shiga toxin-producing Escherichia coli (STEC), Enteropathogenic E. coli (EPEC), and Enterotoxigenic E. coli (ETEC) make up an important group of pathogens causing major animal and public health concerns worldwide. The aim of this study was to determine the prevalence of different pathotypes of E. coli in captive wildlife. We analyzed 314 fresh fecal samples from captive wildlife, 30 stool swabs from animal caretakers, and 26 feed and water samples collected from various zoological gardens and enclosures in India for the isolation of E. coli, followed by pathotyping by multiplex PCR. The overall occurrence rate of E. coli was 74.05% (274/370). The 274 E. coli isolates were pathotyped by multiplex PCR targeting 6 genes. Of them, 5.83% were pathotyped as EPEC, 4.74% as STEC, and 1.09% as ETEC. The 16S rRNA genes from the selected isolates were amplified, sequenced, and a phylogenetic tree was constructed. The phylogenetic tree exhibited indiscriminate genetic profiling and some isolates from captive wild animals had 100% genetic identity with isolates from caretakers, suggesting that captive wildlife may serve as a reservoir for infection in humans and vice-versa. The present study demonstrates for the first time the prevalence of these E. coli pathotypes in captive wildlife in India. Our study suggests that atypical EPEC strains are more frequent than typical EPEC strains in captive wildlife. Discovering the implications of the prevalence of these pathotypes in wildlife conservation is a challenging topic to be addressed by further investigations.

Molecular Characterization of Diarrheagenic Escherichia Coli in Children Less Than 5 Years of Age with Diarrhea in Ouagadougou, Burkina Faso.

Diarrheagenic Escherichia coli (DEC) is important bacteria of children’s endemic and epidemic diarrhea worldwide. The aim of this study was to determine the prevalence of DEC isolated from stool samples collected from children with acute diarrhea living in Ouagadougou, Burkina Faso. From August 2013 to October 2015, stool samples were collected from 315 children under 5 years of age suffering from diarrhea in the “Centre Médical avec Antenne Chirurgicale (CMA)” Paul VI and the CMA of Schiphra. E. coli were isolated and identified by standard microbiological methods, and the 16-plex PCR method was used to further characterize them. Four hundred and nineteen (419) E. coli strains were characterized, of which 31 (7.4%) DEC pathotypes were identified and classified in five E. coli pathotypes: 15 enteroaggregative E. coli (EAEC) (48.4%), 8 enteropathogenic E. coli (EPEC) (25.8%) with 4 typical EPEC and 4 atypical EPEC, 4 enteroinvasive E. coli (EIEC) (12.9%), 3 enterohemorrhagic E. coli (EHEC) 9.67%, and 1 enterotoxigenic E. coli (ETEC) 3.2%. The use of multiplex PCR as a routine in clinical laboratory for the detection of DEC would be a useful mean for a rapid management of an acute diarrhea in children.

Molecular and phenotypic typing of enteropathogenic Escherichia coli isolated in childhood acute diarrhea in Abuja, Nigeria.

Enteropathogenic Escherichia coli (EPEC) causes infectious diarrhea among children in developing countries. However, in Nigeria, due to limited laboratory resources, the genetic diversity of its virulence factors, which includes its intimin subtypes remain undefined. This study aims to evaluate the serotypes, antibiotic resistance and the intimin subtypes genes associated with EPEC strains isolated from children with acute diarrhea in Abuja, Nigeria. EPEC isolates from diarrheic children aged 0-60 months in Abuja, Nigeria were analyzed. PCR for EPEC virulence gene, Hep-2 cell Adherence and serotyping were performed. EPEC strains were further subtyped by PCR reactions for the identification of intimin subtype genes: α (alpha), β (beta), γ1 (gamma-1), and έ (epsilon). Antibiotic resistance and ESBL production was determined by CLSI guidelines. Overall, 18 (4.5%) out of 400 children with acute diarrhea had EPEC infection. Typical EPEC strains were detected in 14 (3.5%) whereas 4 (1.1%) were atypical EPEC. Fifteen (83.3%) of the EPEC isolated belonged to β intimin subtype gene, while the remaining 3 EPEC isolates possessed the intimin έ subtype. No α and γ intimin subtypes were detected. Traditional EPEC serotypes O114:H14 were detected only in tEPEC strains. Marked resistant to β-lactam agents were observed but no ESBL-producing tEPEC or aEPEC was detected. This is the first report of intimin subtype genes in Abuja, Nigeria. These data will be useful in facilitating the characterization of intimin variants of EPEC and some Shiga toxin-producing E. coli (STEC) in humans and other animal species.

Association of Atypical Enteropathogenic Escherichia coli with Diarrhea and Related Mortality in Kittens.

Diarrhea is responsible for the death of approximately 900,000 children per year worldwide. In children, typical enteropathogenic Escherichia coli (EPEC) is a common cause of diarrhea and is associated with a higher hazard of death. Typical EPEC infection is rare in animals and poorly reproduced in experimental animal models. In contrast, atypical EPEC (aEPEC) infection is common in both children and animals, but its role in diarrhea is uncertain. Mortality in kittens is often attributed to diarrhea, and we previously identified enteroadherent EPEC in the intestines of deceased kittens. The purpose of this study was to determine the prevalence and type of EPEC in kittens and whether infection was associated with diarrhea, diarrhea-related mortality, gastrointestinal pathology, or other risk factors. Kittens with and without diarrhea were obtained from two shelter facilities and determined to shed atypical EPEC at a culture-based prevalence of 18%. In contrast, quantitative PCR detected the presence of the gene for intimin (eae) in feces from 42% of kittens. aEPEC was isolated from kittens with and without diarrhea. However, kittens with diarrhea harbored significantly larger quantities of aEPEC than kittens without diarrhea. Kittens with aEPEC had a significantly greater severity of small intestinal and colonic lesions and were significantly more likely to have required subcutaneous fluid administration. These findings identify aEPEC to be prevalent in kittens and a significant primary or contributing cause of intestinal inflammation, diarrhea, dehydration, and associated mortality in kittens.

Captive wild birds as reservoirs of enteropathogenic E. coli (EPEC) and Shiga-toxin producing E. coli (STEC).

Psittacine birds have been identified as reservoirs of diarrheagenic Escherichia coli, a subset of pathogens associated with mortality of children in tropical countries. The role of other orders of birds as source of infection is unclear. The aim of this study was to perform the molecular diagnosis of infection with diarrheagenic E. coli in 10 different orders of captive wild birds in the state of São Paulo, Brazil. Fecal samples were analyzed from 516 birds belonging to 10 orders: Accipitriformes, Anseriformes, Columbiformes, Falconiformes, Galliformes, Passeriformes, Pelecaniformes, Piciformes, Psittaciformes and Strigiformes. After isolation, 401 E. coli strains were subjected to multiplex PCR system with amplification of genes eae and bfp (EPEC), stx1 and stx2 for STEC. The results of these tests revealed 23/401 (5.74%) positive strains for eae gene, 16/401 positive strains for the bfp gene (3.99%) and 3/401 positive for stx2 gene (0.75%) distributed among the orders of Psittaciformes, Strigiformes and Columbiformes. None of strains were positive for stx1 gene. These data reveal the infection by STEC, typical and atypical EPEC in captive birds. The frequency of these pathotypes is low and restricted to few orders, but the data suggest the potential public health risk that these birds represent as reservoirs of diarrheagenic E. coli.

Occurrence and characterization of stx and/or eae-positive Escherichia coli isolated from wildlife, including a typical EPEC strain from a wild boar

Shiga toxin-producing E. coli (STEC) and enteropathogenic E. coli (EPEC) strains are food-borne pathogens associated with acute diarrhea. Haemolytic-uremic syndrome (HUS) is often a complication of STEC infection. In order to examine the occurrence, serotypes, virulence and antimicrobial-resistance profiles of STEC and EPEC in wildlife, 326 faecal E. coli strains from 304 clinically healthy animals were analyzed. For this approach stx1, stx2 and eae genes, as well as accessory virulence determinants (ehx, hlyA, saa, tia, bfp, subAB) were PCR-screened and sequenced. Serotyping was performed employing all available O (O1–O185) and H (H1-H56) antisera. Genetic diversity was analyzed by XbaI-PFGE and phylotyping. Thirteen STEC (4.3%) and 10 EPEC (3.3%) were identified among 12 deer, 3 mouflon, 6 wild boars and 2 birds. Nine STEC showed seropathotypes B (O145:[H28]) and C (O22:H8, O128:[H2]) associated with HUS, and D (O110:H28, O146:H21, O146:[H28], ONT:H8) associated with human diarrhea. Although most isolates harbored stx2b and stx1c variants, stx2a and stx1a (related with severe disease) were also detected. Additionally, the eae gene was present in one stx2a–positive O145:[H28] STEC from a deer and 11 STEC harbored subAB genes (mainly the subAB2 variant). EPEC isolates showed 7 different intimin variants (β1, β2, γ1, ε1, ζ1, ι1-A, κ). Interestingly, the O49:[H10] eae-κ EPEC isolated from a wild boar was bfpA-positive showing a combination of serotype/virulence profile previously detected among human clinical tEPEC. Based on present results, wild ruminants, wild boars and to a lesser extent birds would be carriers of potentially pathogenic STEC and EPEC strains.

Phylogenetic distribution of tir-cytoskeleton coupling protein (tccP and tccP2) genes in atypical enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) strains employ the type III secretion system (T3SS) effector Tir to induce actin cytoskeletal rearrangements. While some EPEC require tyrosine phosphorylation (Y-P) of Tir to trigger actin assembling, certain strains whose Tir is not tyrosine phosphorylated utilize the T3SS effector Tir-cytoskeleton coupling protein (TccP/TccP2) for efficient actin polymerization. The presence of tccP/tccP2 in typical EPEC belonging to distinct evolutionary lineages is well established but, in contrast, little is known about the distribution of these genes in atypical EPEC (aEPEC) showing distinct phylogenetic background. In this study, we screened 72 pathogenic aEPEC for the presence of tccP/tccP2 genes, and further characterized positive strains regarding tir type, phylogroups and production of TccP/TccP2. The tccP and/or tccP2 genes were detected in 45.8% of the strains, with a predominance of tccP2 allele. Most of these strains carried tirY-P, suggesting that can trigger actin polymerization using both Tir tyrosine phosphorylation and TccP/TccP2 pathways. aEPEC strains carrying tccP or tccP2 were significantly associated to phylogroups E and B1, respectively. We also observed a strain-to-strain variation regarding TccP/TccP2 production. Our results demonstrate a wide distribution of tccP/tccP2 genes among pathogenic aEPEC strains, as well associations between specific alleles and phylogenetic backgrounds.