Enteric pathotypes of Escherichia coli involved in infectious diarrhoeal syndrome

Abstract number: P1823

Nica M., Biolan T., Mozes E., Dascalu A., Caliga D., Rusu R., Homos M., Melinte V., Florescu S., Ceausu E., Calistru P., Damian M., Usein C.R., Apostol I., Kosa A.

Objectives: 1.Assessment of incidence for enteric pathogenic strains of E. coli in a samples of patients with acute diarrhoeal syndrome (ADS), with or without concomitant HIV infection. 2.Assessment of the role of classical diagnostic versus genotypical methods, in diagnosing ADS caused by E. coli.

Methods: The study included 1830 patients, with ADS, hospitalised in SVB, between 1st Jan 2006–31 June 2007. There were excluded other cases of infectious diarrhoea, except E. coli: viruses, parasites, other enteral bacterial pathogens. The classical methodology was based on isolation, phenotypic identification and serological testing. Isolation was made on mild/moderate selective media (MacConkey, SMAC, CLED, Hektoen/ADCL). Phenotypic identification was based on growth culture proprieties on multitests media: TSI, MIU, MILF, Citrate and confirmated by: API 20 E, ID 20 E, VITEK 2 C. Serology was based on antigenity criteria: serotyping OB (Denka Seiken, Tokio, Japan). Microscopic examination, macroscopic aspects and epidemiological data were used for obtaining an oriented stool culture for E. coli. Internal quality control was provided by using E. coli ATCC 25922. All strains of E. coli isolated in pure culture were analyzed through multiplex PCR in INCDMIC.

Results: We identified 410 strains of E. coli: 369 HIV(-) and 41 HIV(+), the most ones at the age group 0–5 years: 74.3% cases. Enteric pathogenic E. coli was identified by phenotypical methods in 12.29% (46 strains) and by molecular methods in 13.12% (54 strains). We identified 31.5% EPEC pathotype, 0.7% EIEC pathotype and 0.5% EHEC pathotype by phenotypical tests. The molecular tests showed 5.12% atypical EPEC (eae gene), 0.7% typical EPEC (bfp and eae genes), 2.7% atypical STEC/VTEC (with one gene or association of 2–3 genes: eae, stxI, stxII, mdh), 0.2% typical STEC/EHEC (all 4 genes), 4.4% EAEC (agg gene), 0% EIEC and ETEC (genetic unconfirmed). There were no enteric pathogenic strains of E. coli isolated from HIV (+) patients.

Conclusions: 1. Pathotyps of E. coli was confirmed by genotypical methods, only in HIV(-) patients; in HIV(+) patients, ADS occured by other non-infectious pathophysiological mechanisms of SIDA. 2. In diagnosing enteric pathotypes of E. coli, a comparative analyse of the two techniques used, lead to superior results for genetic methods versus phenotypical methods (13.12% versus 12.29%).

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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