Comparison between virulence characteristics of dominant and non-dominant Escherichia coli strains of the gut and their interaction with Caco-2 cells. (April 2017)

• Record Type: Journal Article
• Authors: Owrangi, B.; Masters, N.; Vollmerhausen, T.L.; O'Dea, C.; Kuballa, A.; Katouli, M.
• Is Part Of: Microbial pathogenesis. Volume 105(2017)
• Page Start: 171
• Page End: 176
• Publication Date: 2017-04
• Subjects: E. coli -- Caco-2 cells -- Invasion -- Virulence genes -- Translocation; Pathogenic microorganisms -- Periodicals; Pathology, Molecular -- Periodicals; Communicable Diseases -- microbiology -- Periodicals; Communicable Diseases -- parasitology -- Periodicals; Micro-organismes pathogènes -- Périodiques; Pathologie moléculaire -- Périodiques; Electronic journals; 616.9041
• DOI: 10.1016/j.micpath.2017.02.032
• Languages: English
• ISSNs: 0882-4010

Abstract

Abstract: Escherichia coli strains are normal inhabitants of the gut and are normally found in the faeces of the host at different population sizes. We characterised faecal E. coli of 45 healthy male (n = 17) and female (n = 28) volunteers by testing 28 isolates from each individual. These isolates were typed and divided into dominant (if constituted >50% of the population tested) and non-dominant types in each individual. Representative strains of each dominant and non-dominant type were tested for their virulence gene profiles, their ability to form biofilm, adhere to, invade and translocate through a gut epithelial cell line (Caco-2 cells). Strains belonging to dominant types adhered significantly more to Caco-2 cells than non-dominant strains (5.7 ± 0.3 versus 4.3.± 0.13 CFU/cell mean ± SEM, P = 0.0003). They also invaded (135 ± 6 versus 63 ± 13 CFU) and translocated through Caco-2 cells (84 ± 5 versus 32 ± 9 CFU) significantly more than non-dominant strains (P < 0.0001 and P = 0.0002, respectively). Moreover, dominant strains showed the ability to form significantly more biofilm than non-dominant strains (1.1 ± 0.01 versus 0.5 ± 0.1 OD600, P < 0.0001). Majority (51%) of the strains belonged to phylogroup D followed by B2 (23%). Furthermore, out of 25 virulence genes tested, kps MTII, pap C and pap G allele III were found to be significantly higher among dominant than non-dominant strains. Our results suggest that E. coli strains dominating the gut may have virulence properties that enable them to efficiently interact with the gut epithelium and translocate under predisposing conditions of the host. Highlights: Dominant E. coli of the gut have a better ability to adhere to, invade and translocate a human gut epithelium. These strains also showed to form biofilm and carried significantly more virulence genes than non-dominant strains. Majority of E. coli strains in faecal samples belonged to phylogroup D followed by B2. There was a greater variation in the number of non-dominant types in male subjects compared to female subjects.