Cell free preparations of probiotics exerted antibacterial and antibiofilm activities against multidrug resistant E. coli

Abdelhamid, Ahmed G.; Esaam, Aliaa; Hazaa, Mahmoud M.

Escherichia coli is considered as a member of the dominant flora inhabiting the human colonic region. Although most of the members of this species are harmless to the intestinal lumen, some acquired virulence factors and can cause a wide range of human diseases (Nataro et al., 1998) . The pathogenic E. coli is causative of three clinical syndromes: urinary tract infections, enteric/diarrheal diseases and meningitis (Kaper et al., 2004) . The key mechanisms by which E. coli cause enteric diseases include attachment and colonization of the intestinal mucosa, manipulation of the host cell cytoskeleton or evading host immune defenses, and production of toxins (Torres, 2009) . Six categories of pathogenic E. coli are well-studied and comprise enteropathogenic E. coli, enterotoxigenic E. coli, enteroaggregative E. coli, enterohaemorrhagic E. coli, diffusely adherent E. coli and enteroinvasive E. coli (Croxen and Brett Finlay, 2012; Kaper et al., 2004) . Diarrheal diseases caused by E. coli worldwide were estimated to be nearly 300-800 million clinical cases and 300,000-500,000 deaths every year (Torres, 2009) ; this highlights the significance of pathogenic E. coli in global health burden imposed by diarrheal diseases. Current interventions to inactivate/eliminate pathogenic E. coli involve the use of antibiotics. However, many pathogenic strains that are able to cause illness have become resistant to antibiotics (Collignon, 2009; Tadesse et al., 2012) . The rise of antibiotic resistance has motivated research to find out antimicrobial alternatives of which probiotics have gained a growing interest.