title: Prevalence and virulence characteristics of enteroaggregative Escherichia coli in a case-control study among patients from Iran.
abstract: Enteroaggregative Escherichia coli (EAEC) is an important agent of diarrhoeal diseases worldwide. The role of EAEC virulence factors in the clinical outcome of infection is not completely defined. This case-control study investigated the prevalence of EAEC, its virulence genes and the antimicrobial resistance profile of adult patients with and without diarrhoea attending three different hospitals in Zanjan, Iran. A total of 550 individual stool specimens (350 from diarrhoeal patients and 200 from patients without diarrhoea) were collected. One hundred and forty-one EAEC isolates were identified by a HEp-2 cell assay and PCR. EAEC isolates were detected with slightly higher frequency in patients with (27.7%) than in patients without (22%) diarrhoea (P ≥ 0.05). The EAEC genes aggR, aap and pet were identified more frequently in case patients compared with controls (P ≤ 0.05). Many of the EAEC isolates from the diarrhoeal patients had two or more virulence genes compared with those without diarrhoea (P ≤ 0.05). EAEC isolates exhibited high-level resistance to amoxicillin (82.3%), co-amoxiclav (78%), aztreonam (73.8%), tetracycline (66.6%) and ceftazidime (63.8%). In addition, 53.2% of isolates were resistant to at least three different classes of antimicrobial agents and were considered to be multidrug resistant. These results indicate a high prevalence and heterogeneity of gene profiles of EAEC in diarrhoeal and control patients, and suggest that the presence of aggR, aap and pet, the number of genes present and the antimicrobial resistance profile may be markers for more-virulent EAEC isolates.
authors: Department of Microbiology, Zanjan University of Medical Sciences, Zanjan, Iran.
authors: Saeed
authors: S
authors: Bafandeh
authors: Department of Microbiology, Zanjan University of Medical Sciences, Zanjan, Iran.
authors: Fakhri
authors: F
authors: Haghi
authors: Department of Microbiology, Zanjan University of Medical Sciences, Zanjan, Iran.
authors: Habib
authors: H
authors: Zeighami
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016022:Case-Control Studies; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D056945:Hep G2 Cells / Q000382:microbiology; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D015995:Prevalence; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors