Genotypic and phenotypic characteristics in association with biofilm formation in different pathotypes of human clinical Escherichia coli isolates.

In this study, we genotypically and phenotypically characterized 187 human clinical E. coli isolates representing various pathotypes (e.g., uropathogenic, enteropathogenic and enteroaggregative E. coli). We investigated the presence of biofilm-associated genes ("genotype") and phenotypically analyzed the isolates for motility, curli and cellulose production ("phenotype"). We developed a new screening method to examine the in vitro biofilm formation ability. In summary, we found a high prevalence of biofilm-associated genes. However, we could not detect a biofilm-associated gene or specific phenotype correlating with the biofilm formation ability. In contrast, we could identify an association of increased biofilm formation with a specific E. coli pathotype. Enteroaggregative E. coli (EAEC) were found to exhibit the highest capacity of biofilm formation. Using our image-based technology for the screening of biofilm formation, we have demonstrated the characteristic biofilm formation pattern of EAEC, consisting of thick bacterial aggregates. In summary, our results highlight the fact that biofilm-promoting factors shown to be critical for biofilm formation in non-pathogenic strains do not reflect their impact in clinical isolates and that the ability of biofilm formation is a defined characteristic for EAEC.IMPORTANCE Bacterial biofilms are ubiquitous and consist of sessile bacterial cells surrounded by a self-produced extracellular polymeric matrix. They cause chronic and devic...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research