Assessment of virulence potential of Escherichia coli isolated from clinical and non-clinical sources in port Harcourt, Nigeria.

Abstract

Escherichia coli commonly occurs as a normal flora found in a variety of gastrointestinal tracts. However, certain strains acquire virulence characteristics. Potentially pathogenic species have also been isolated in non-clinical environments.This often raises concerns on the role these environments play in transmission. This study aimed to assess the occurrence of virulence traits in Escherichia coli isolated from non-clinical and clinical sources in Port Harcourt, Nigeria. Two hundred samples from clinical (urine and stool) and non-clinical (soil and poultry) sources were analyzed. 8 isolation, purification and identification of E. coli isolates were performed using standard bacteriological and biochemical tests. Out of the 200 samples collected, 98 isolates (49%) were confirmed as E. coli. Confirmed E. coli isolates were then tested for virulence using standard phenotypic tests (protease, colicin, congo red, hemolysin, haemagglutination, adhesin and mannose resistant/sensitive haemagglutination). E. coli strains from clinical samples displayed a number of virulence traits ranging frombiofilm producing capabilities (53%), congo red binding propensity (24%), colicin (34%), protease (15%) and hemolysin production (4%) compared to their non-clinical counterpart. All samples were negative for haemagglutination. The total virulence prevalence of E. coli was 81%. Clinical samples possessed more virulence traits (71%) than samples from non-clinical sources (29%), with urine having a higher occurrence among the clinical samples (36%). There is need for an in-depth study on virulence attributes of E. coli and ways to control these factors to minimize the rate of spread and the degree of infections.