Pathogenicity island I of Escherichia coli CFT073 and Yersinia high-pathogenicity island are significantly associated with persistence of E. coli in the intestine of Swedish infants

Abstract number: p1171

Östblom  A.E., Adlerberth  I., Wold  A.E., Nowrouzian   F.L.

Objectives: 

Virulence associated genes are often located on particular regions on the bacterial chromosome, termed pathogenicity islands. Uropathogenic Escherichia coli strains often carry pathogenicity islands, such as the pathogenicity island I (PAI ICFT073) first identified in the uropathogenic E. coli strain CFT073 and the high-pathogenicity island (HPI) originally found in Yersinia species. We have examined whether these pathogenicity islands may contribute to persistence of E. coli in its normal niche, the colonic microflora.

Methods: 

E. coli obtained from 70 Swedish infants followed with regular sampling of the faecal flora over the first year of life were analyzed. The E. coli isolates were been identified to the strain level by Random Amplified Polymorphic DNA (RAPD). A total of 148 strains were classified, of these 58 strains were resident (persisting for >= 3 wk in the microflora) and 19 could be classified as transient (persisting for <= 3 wk in the micro flora). The strains were assessed for carriage of PAI ICFT073 and HPI, by the use of a single PCR and a duplex PCR assay, respectively.

Results: 

Fifty six and 47% percent of the E. coli strains harboured HPI and PAI ICFT073 respectively. Resident strains significantly more often than transient strains possessed PAI ICFT073 (66% vs. 21% p = 0.001) and HPI (70% vs. 37% p = 0.01).

Conclusion: 

Our results indicate that HPI and PAI ICFT073 enhance the colonization capacity of E. coli strains in the intestine. The virulence associated traits characterizing resident E. coli strains may contribute to the persistence in the intestinal micro flora as well as increase their pathogenic capability in the urinary tract.