title: Phenotypic and genotypic characterization of enteroaggregative Escherichia coli isolates from pediatric population in Pakistan.
abstract: Enteroaggregative Escherichia coli (EAEC) are a leading cause of diarrhea among children. The objective of this study was to define the frequency of EAEC among diarrheal children from flood-affected areas as well as sporadic cases, determine multidrug resistance, and evaluation of virulence using an in vivo model of pathogenesis. Stool samples were collected from 225 diarrheal children from 2010 to 2011 from flood-affected areas as well as from sporadic cases in Pakistan. Identified EAEC isolates were characterized by phylogrouping, antibiotic resistance patterns including the extended-spectrum beta lactamase spectrum, single nucleotide polymorphism detection in gyrA and parC, and virulence potential using wax worm, G. mellonella. A total of 35 (12.5%) confirmed EAEC isolates were identified among 225 E. coli isolates. EAEC isolates displayed high resistance to tetracycline, ampicillin, and cefaclor. A total of 34.28% were ESBL positive. Single nucleotide polymorphism detection revealed 37.14% and 68.57% isolates were positive for SNPs in gyrA (A660 -T660 ) and parC (C330 -T330 ), respectively. Phylogrouping revealed that B2 phylogroup was more prevalent among all EAEC isolates tested followed by D, A, B1, and non-typeable (NT). Infection of G. mellonella with EAEC showed that killing infective dose was 100% higher than E. coli DH5 alpha control. EAEC are prevalent among Pakistani children with diarrhea, they are highly resistant to antibiotics, and predominantly fall into B2 phylogroup. Epidemiologic surveillance of EAEC and other E. coli pathotypes is critical to assess not only the role of these pathogens in diarrheal disease but also to determine the extent of multidrug resistance among the population.
authors.affiliation: COMSATS Institute of Information Technology, Islamabad, Pakistan.
authors.forename: Uzma
authors.initials: U
authors.lastname: Khalil
authors.affiliation: COMSATS Institute of Information Technology, Islamabad, Pakistan.
authors.forename: Mahwish
authors.initials: M
authors.lastname: Younus
authors.affiliation: Biological Production Division, National Institute of Health, Islamabad, Pakistan.
authors.forename: Naeem
authors.initials: N
authors.lastname: Asghar
authors.affiliation: COMSATS Institute of Information Technology, Islamabad, Pakistan.
authors.forename: Fariha
authors.initials: F
authors.lastname: Siddiqui
authors.affiliation: Division of Pediatric Infectious Diseases, Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA.
authors.forename: Oscar G
authors.initials: OG
authors.lastname: Gómez-Duarte
authors.affiliation: Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Brendan W
authors.initials: BW
authors.lastname: Wren
authors.affiliation: COMSATS Institute of Information Technology, Islamabad, Pakistan. habib@comsats.edu.pk.
authors.forename: Habib
authors.initials: H
authors.lastname: Bokhari
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001681:Biological Assay; D002675:Child, Preschool; D027081:DNA Gyrase / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology*; D004195:Disease Models, Animal; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007915:Lepidoptera; D008297:Male; D010154:Pakistan / Q000453:epidemiology; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D016019:Survival Analysis; D014774:Virulence; D037521:Virulence Factors / Q000032:analysis* / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors; D001618:beta-Lactamases; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase
keywords: Enteroaggregative Escherichia coli; antibiotic resistance; extended-spectrum beta lactamases; phylogroups; single nucleotide polymorphism; virulence potential