Escherichia coli nas infeções urinárias da comunidade: comensal ou patogénica?

Abstract

Objective

To study Escherichia coli pathogenicity in urinary tract infections and their relationship with the host. Association of bacteriuria by E. coli with defined pathogenicity criteria or host specific conditions, in women aged up to 59 years.

Materials and methods

Overall 228 Escherichia coli strains were studied. These were isolated from urine of women with age ≤ 59 provided by various Portuguese laboratories in the community. The study of the virulence genes fimH, papC, ecpA, usp, hlyA and cnf1, pathogenicity islands (PAI) I_CFT073 and PAI II_CFT073, and phylogenetic group determination was performed by PCR.

Results

The most frequently isolated genes were ecpA, followed by fimH and the most prevalent phylogenetic groups were pathogenics B2 and D, both in cITU and ncITU.

Both commensal and pathogenic isolates showed presence of fimH, papC and ecpA genes with functions in adhesion and colonization, while usp, hlyA and cnf1 usually associated with invasive strains and PAI I_CTF073 and PAI II_CFT073 were found predominantly in pathogenic group strains.

Conclusion

Studied virulence factors were not restricted to pathogenic strains, both in ncITU and cITU. The host risk factors which propitiate cystitis such as pregnancy, recurrence and diabetes, are associated with bacterial pathogenicity.