Molecular analysis of typical and atypical enteropathogenic Escherichia coli (EPEC) isolated from children with diarrhoea (original) (raw)
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Journal of Infection and Chemotherapy, 2013
The aim of this study was to investigate the genetic diversity and class 2 integron content of typical and atypical enteropathogenic Escherichia coli (EPEC) strains isolated from children less than 5 years of age. Biochemical tests and serogrouping were performed for identification of isolated strains, and each isolate was tested for susceptibility to 7 antimicrobial agents. The identity of EPEC and their class 2 integron content was confirmed by PCR analysis and sequencing. Subtyping of Escherichia coli spp. was performed through pulsed-field gel electrophoresis (PFGE) analysis. All EPEC strains were resistant to 6 antimicrobial agents except for gentamycin. The most prevalent serogroups among EPEC strains were found to be members of O86 and O127 serogroups (37.7 %) and O44, O125, and O128 (42.8 %). The majority of our EPEC isolates (60.7 %) were identified as atypical. Among the total 28 isolates, 4 (14.2 %) harbored a class 2 integron 1,500 or 2,300 bp in size, corresponding to dfrA1-sat1 and dfrA1-sat1-aadA1 resistance gene cassette arrays, respectively. PFGE analysis showed an extensive diversity among the isolates. No PFGE clustering was observed according to bundle-forming pilus (bfp) bacteria, suggesting that PFGE analysis could not discriminate between typical and atypical EPEC strains. The high ratio of antibiotic-resistant strains and the large heterogeneity among EPEC isolates with low prevalence of class 2 integrons signify the need to examine for other mechanism(s) involved in conferring resistance in typical and atypical populations of EPEC.
2003
Enteropathogenic Escherichia coli (EPEC) is a leading cause of diarrhea among infants in developing countries. A total of 38 EPEC isolates, obtained from diarrhea patients of Hospital Miri, Sarawak, were investigated through plasmid profile, antibiotic resistance and randomly amplified polymorphic DNA (RAPD) analysis. From the 8 types of antibiotics used, all isolates were 100% resistant to furoxime, cephalothin and sulphamethoxazole and showed high multiple antibiotic resistant (MAR) indexes, ranging from 0.5 to 1.0. In plasmid profiling, 22 isolates (58%) showed the presence of one or more plasmids in the range 1.0 to 30.9 mDa. The dendrogram obtained from the results of the RAPD-PCR discriminated the isolates into 30 single isolates and 3 clusters at the level of 40% similarity. The EPEC isolates were highly diverse, as shown by their differing plasmid profiles, antibiotic resistance patterns and RAPD profiles.
International Journal of Infectious Diseases, 2011
Enteroaggregative Escherichia coli (EAEC) strains are an emerging type of diarrheagenic E. coli. The aim of this study was to investigate the frequency of EAEC in children with diarrhea by polymerase chain reaction (PCR) method targeting the pCVD432 gene. The presence of virulence genes including aggR, aggA, aafA, aap, and astA was also investigated by PCR, for the differentiation of typical and atypical EAEC strains. We also sought to determine the antibiotic resistance pattern of the isolated strains.Stool samples were collected from 140 children with diarrhea at Besat Hospital, Hamadan, Iran, from July 2007 to May 2008. The specimens were cultured for E. coli, which was identified using standard methods. E. coli strains were screened for EAEC by PCR and HeLa cell line adherence methods. For each sample, five single colonies (700 E. coli strains) from original MacConkey plates were examined for pCVD432, aggR, aggA, aafA, aap, and astA genes using PCR. The EAEC adherence patterns were examined by HeLa cell adherence method. Antimicrobial susceptibility testing was performed as the Clinical and Laboratory Standards Institute (CLSI) guidelines.Overall, 15 (10.7%) EAEC strains were identified in 140 diarrhea cases by PCR. Out of these isolates, EAEC were detected in 13 (86.7%) by the HeLa cell assay. The aggR regulon was present in 11 (73.3%) strains. Several different combinations of the virulence markers were found among the EAEC isolates. The most prevalent (20%) combination was aggR–aap–astA. The EAEC isolates exhibited resistance to ampicillin (100%), erythromycin (100%), cephalothin (78.6%), co-trimoxazole (71.4%), tetracycline (64.3%), and nalidixic acid (57.1%) and reduced resistance to ciprofloxacin (42.9%) and norfloxacin (7.1%).EAEC is a diarrheal pathogen of emerging importance. Correlation between pCVD432 PCR and the HeLa cell line assay was confirmed in children with diarrhea. In comparison to the assay for aggregative adherence, the EAEC PCR has been found to be simple and specific in many epidemiological studies. The typical EAEC (73.3%) strains (with pCVD432 and aggR genes) identified in this study were heterogeneous with respect to virulence genes. This study also showed that EAEC isolates were highly resistant to tetracycline, co-trimoxazole, and ampicillin, which are the most commonly used antibiotics in our area.
Jundishapur Journal of Microbiology
Background: Enteropathogenic Escherichia coli (EPEC) is one of the most important pathogens among young children worldwide. Both eae and bfp genes have been used to identify EPEC strains and categorize them into typical and atypical strains. They may be an emerging pathogen in both developing and developed countries. Objectives: This study was primarily conducted to assess the epidemiology, drug resistance, and β-lactamase distribution of EPEC, as well as the detection of efa1/lifA in atypical strains. Methods: A total of 251 E. coli strains isolated from children with diarrhea were evaluated for their EPEC pathotype by PCR for the presence of eae, stx1, stx2, and bfp genes. Serogrouping with polyvalent antisera was performed to confirm EPEC strains. Atypical EPEC-containing samples were evaluated for the efa1/lifA gene. EPEC isolates were assessed to recognize the antibiotic resistance and screened to detect extended-spectrum β-lactamases (ESBLs). Results: Enteropathogenic E. coli ...
Archives of Pediatric Infectious Diseases
Background: Acute diarrhea, a leading cause of morbidity and mortality worldwide, still remains a major global health problem, especially among children in the developing countries. Diarrheagenic E. coli represent one of the most common etiological causes of diarrhea in children worldwide. Objectives: This study was conducted in order to determine the rate of Enteroaggregative E. coli (EAEC) among 50 E. coli isolates as well as its antimicrobial resistance patterns. Methods: A total of 50 Escherichia coli strains had been isolated among children under 5 years of age during 75 reported outbreaks in various provinces of Iran from October 2013 to May 2014. PCR was employed for the identification of different groups of diarrheagenic E. coli. Antimicrobial susceptibility testing was performed using disc diffusion methods. In addition, extended spectrum beta-lactamase (ESBL) production ability was checked by way of combination disc methods of CLSI. Minimum inhibitory concentration of cefotaxime, ceftriaxone, and ceftazidime in EAEC with the ability of ESBL production was determined using the micro-broth dilution method of CLSI. Results: Out of the 50 E. coli isolates, 17 were identified as Enteroaggregative E. coli (EAEC) in that they were positive for at least 1 of the 2 tested virulent genes: agg and aap. ESBL production ability was observed in 4/17 (23.5%) EAEC isolates. MIC of cefotaxime and ceftriaxone in ESBL positive EAEC varied between 8-32 µg/mL and 8-64 µg/mL, respectively. Resistance to ampicillin and nalidixicacid (47.1%), trimethoprim/sulfamethoxazole (41.2%), and ciprofloxacin (11.8%) was observed among the EAEC isolates. No evidence of resistance to gentamycin and meropenem was detected. Conclusions: This research has revealed that the most common type of diarrheagenic E. coli among children, who were affected in the diarrheal outbreak in different cities of the country, is Enteroaggregative E. coli (34%). The rate of ESBL positive cases in EAEC isolates were 23.5 %.
International Journal of Current Microbiology and Applied Sciences
Diarrheal diseases are a major cause of morbidity and mortality in developing countries. In the past decades several new enteric pathogens, including bacterial, viral, and parasitic agents have been described. Escherichia coli (Esch. coli) is one of the leading cause of acute diarrhea in developing countries in children under 5 years old, with significant morbidity and mortality. The present study was carried out in the Department of Microbiology Mayo Institute of Medical Sciences and Research Lucknow. The study group included 81 children suffering from diarrhoea attending the inpatient or outpatient sections of the Department of Paediatrics. Among the bacterial pathogens detected, Esch. coli was the commonest. In the present study major symptoms reported were diarrhea, fever and vomiting. Examination of stool samples showed that 32 (39.5%) children harbored one or more of the Escherichia coli pathotypes. Out of those 32 who were subjected to serotyping 9 (28.12%) were untypable and 5 (15.62%) were rough strains. Of the typable strains, Enteropathogenic E.coli (EPEC) accounted for 3.12%, Enterotoxicogenic E.coli (ETEC) accounted for 12.5%, Enterohaemorragic (EHEC) accounted for 3.12 %. Of the ETEC strains, serogroups O173 (1), O11 (1), O15 (1) and O8 (1) were found. The EPEC strain found was O86 and EHEC was serogroup O172. Among the other serogroups which comprised of 37.5% strains, O161 (3) was predominant. Antibiotic resistance was documented for Ampicillin (100%).
Ribotyping of EPEC isolates from diarrheal and asymptomatic patients in Iran
Gastroenterology and hepatology from bed to bench, 2012
We intended to find out the diversity of EPEC isolates among asymptomatic or diarrheal children in Iran using ribotyping. Enteropathogenic Escherichia coli (EPEC) is responsible for gastroenteritis especially in young children. A total of 39 EPEC collected strains were serotyped and the presence of virulence genes as well as EAF plasmid among the strains was studied. Adherence assay was also performed. Clonal diversity of the isolates was investigated using ribotyping. Of 39 studied strains of E. coli, 6 serogroups of EPEC were represented. The presence of the stx gene was ascertained in 7 isolates and the eaeA, eaeB and bfpA genes were harbored by 5, 3 and 1 strains, respectively. Ribotyping yielded 9 different clusters. According to our results there was not a significant correlation between the results of serotyping and those of ribotyping. However, different serotypes of E. coli may belong to the same ribotype clusters and vice versa.
Ibrahim Medical College Journal, 2015
Enteropathogenic Escherichia coli (EPEC) mediated infantile diarrhoea among children is an important cause of morbidity and mortality in developing countries. The antimicrobial susceptibility pattern of EPEC strains isolated from children under 5 years of age was studied. Stool samples from 272 patients with diarrhoea were collected from two tertiary care hospitals. Out of 272 stool samples, 20 (7.35%) isolates were identified as EPEC on the basis of presence of bfpA gene detected by polymerase chain reaction and antibiotic susceptibility testing was performed on these EPEC strains by Kirby-Bauer disc diffusion method. The antimicrobial susceptibility test revealed that the EPEC isolates were highly resistant to ampicillin (100%), nalidixic acid (95%) and tetracycline (95%) and were sensitive to ceftazidime (95%), cefotaxime (90%), ceftriaxone (95%), imipenem (100%) and levofloxacin (85%). Isolation of EPEC is of great importance since they are responsible for acute diarrhoeal diseases in large number of children under the age of five years. The high antimicrobial resistance observed in our study indicates indiscriminate or improper use of antimicrobials, besides the risks of self-medication.
J Infect Dev Ctries 2014; 8(5): 589-596. doi:10.3855/jidc.4077.
Introduction: Little information is available regarding the significance of enteroaggregative Escherichia coli (EAEC) in pediatric diarrhea in Egypt. Methodology: Escherichia coli was isolated from stool samples of 62 diarrheic and 43 non-diarrheic (control) Egyptian children. Samples were screened for genes specific for enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli (STEC), and enteroinvasive E. coli (EIEC) using polymerase chain reaction (PCR). Diarrheagenic E. coli were grouped phylogenetically using PCR and tested for their susceptibility to antibiotics using the disk diffusion method. Isolates designated as EAEC were examined for eight virulence factors (VFs) using PCR. Results: EAEC was detected in 19 (30.7%) and 4 (9.3%), EPEC in 2 (3.2%) and 1 (2.3%), and ETEC in 2 (3.2%) and 0 (0.0%) diarrheic and control children, respectively; STEC and EIEC were not detected. Only EAEC was significantly isolated from diarrheic children compared with controls (p < 0.01, OR = 4.31).Three or more VFs (multivirulent isolates) were found in 52.6% and 50% of EAEC isolated from diarrheic children and controls, respectively. More than 73% (17/23) of EAEC isolates were identified as belonging to phylogenetic group D. Multiple-antibiotic resistance (resistance to three or more drugs) was observed in more than 91% of EAEC. Conclusions: Multivirulent EAEC is a significant causative agent of pediatric diarrhea in Egypt, with the majority of isolated EAEC belong to phylogenetic group D. Multiple-antibiotic resistance among EAEC has the potential to be a serious public health problem for the country.
Infection and Drug Resistance, 2018
Introduction: Enteroaggregative Escherichia coli (EAEC) has been implicated as an emerging cause of traveler's diarrhea, persistent diarrhea among children, and immunocompromised patients. The present study aimed to investigate the prevalence of antibiotic resistance, extendedspectrum β-lactamase (ESBL) production, and virulence factors of EAEC isolates obtained from Iranian children suffered from diarrhea. Materials and methods: In this cross-sectional study, from March 2015 to February 2016, 32 EAEC isolates were collected from fecal samples of children aged <12 years with diarrhea in southwest of Iran. All EAEC isolates identified using phenotypic and molecular methods and the cell line adhesion assay. Antimicrobial susceptibility testing was determined using disk diffusion method. The presence of virulence factors and ESBL resistance genes were determined by polymerase chain reaction. Results: Overall, 28.1% (9/32) of the isolates were positive for at least one of virulence genes. The most frequent gene was aap with a frequency of 96.9%. Neither aafA nor aggA gene was detected among all of the EAEC isolates. Antimicrobial susceptibility testing revealed the highest resistance rate to ampicillin (100%) and co-trimoxazole (100%), followed by ceftriaxone (81.3%). Further analysis revealed that the rate of ESBLs-producing isolates was 71.9% (23/32). Polymerase chain reaction screening revealed that 87.5% and 65.5% of EAEC isolates were positive for bla TEM and bla CTX-M genes, respectively, and 17 (53.1%) of isolates contained both bla TEM and bla CTX-M genes. Conclusion: The high detection rate of ESBL-producing EAEC isolates accompanied with virulence genes highlights a need to restrict infection control policies in order to prevent further dissemination of the resistant and virulent EAEC strains.