+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Novel biofilm formation by enteroaggregative Escherichia coli

Novel biofilm formation by enteroaggregative Escherichia coli

Abstracts of the General Meeting of the American Society for Microbiology 101: 442

Enteroaggregative Escherichia coli (EAEC) is an emerging cause of diarrhea in adults and children. The organism has been observed to form thick biofilms of aggregating bacteria in in vivo models. To elucidate the requirements for biofilm formation, we developed an in vitro model for EAEC biofilm, characterized the EAEC biofilm, and screened for mutations that were deficient in biofilm-forming ability. Our results suggest that most EAEC strains are capable of forming a thick biofilm on glass or plastic in minimal essential medium with a high concentration of sugar. In prototype EAEC strain 042, biofilm-forming ability was dependent on the ability of the strain to express the fimbriae AAF/II, although many other EAEC strains that do not express AAF/II were also able to build similar biofilms. In contrast to previously described E. coli K12 biofilms, flagella and type 1 fimbriae were apparently not required for EAEC biofilm formation. We screened 10,000 transposon mutants and identified 100 that were deficient in biofilm formation. Of these, 93 were either deficient in in vitro growth or mapped to genes known to be required for AAF/II expression. Of the 7 remaining insertions, we identified two new loci that were required for biofilm formation. Two insertions mapped to the E. coli chromosomal fis gene, a DNA binding protein that is involved in growth phase dependent regulation. Complementation of the fis mutation resulted in restoration of wild type biofilm formation. Using RT-PCR we determined that the effect of fis was at the level of transcription of the AAF/II activator aggR. We also found that biofilm formation required the product of the yafK gene, which encodes a 28 kDa previously hypothetical protein that features a strongly predicted signal sequence. Complementation of the yafK mutations restored biofilm formation. The yafK product is required for expression of AAF/II at the post-transcriptional level. Our data suggest that EAEC forms a novel biofilm, which depends on growth phase-dependent expression of AAF fimbriae.

Please choose payment method:

(PDF emailed within 1 workday: $29.90)

Accession: 035408035

Download citation: RISBibTeXText

Related references

Roles for fis and yafK in biofilm formation by enteroaggregative Escherichia coli. Molecular Microbiology 41(5): 983-997, 2001

Characterization of typical and atypical enteroaggregative escherichia coli in Kagoshima, Japan: biofilm formation and acid resistance. Microbiology and Immunology 54(6): 320-329, 2010

Influence of Lactobacillus casei on biofilm formation by enteroaggregative Escherichia coli strains isolated from irritable bowel syndrome (IBS). Medycyna Doswiadczalna i Mikrobiologia 65(1): 11-17, 2013

Iron-limited condition modulates biofilm formation and interaction with human epithelial cells of enteroaggregative Escherichia coli (EAEC). Journal of Applied Microbiology 108(1): 246-255, 2010

The shf gene of a Shigella flexneri homologue on the virulent plasmid pAA2 of enteroaggregative Escherichia coli 042 is required for firm biofilm formation. Current Microbiology 56(5): 474-480, 2008

Natural plant products inhibits growth and alters the swarming motility, biofilm formation, and expression of virulence genes in enteroaggregative and enterohemorrhagic Escherichia coli. Food Microbiology 59: 124-132, 2016

Quantitative biofilm assay using a microtiter plate to screen for enteroaggregative Escherichia coli. American Journal of Tropical Medicine and Hygiene 71(5): 687-690, 2004

Quantitative biofilm assay using microtiter plate to screen for enteroaggregative Escherichia coli. Abstracts of the General Meeting of the American Society for Microbiology 103: C-367, 2003

Association of putative enteroaggregative Escherichia coli virulence genes and biofilm production in isolates from travelers to developing countries. Journal of Clinical Microbiology 45(1): 121-126, 2007

Diarrhea-associated biofilm formed by enteroaggregative Escherichia coli and aggregative Citrobacter freundii: a consortium mediated by putative F pili. Bmc Microbiology 10: 57, 2010

Nitazoxanide inhibits biofilm production and hemagglutination by enteroaggregative Escherichia coli strains by blocking assembly of AafA fimbriae. Antimicrobial Agents and ChemoTherapy 54(4): 1526-1533, 2010

Identification of enteroaggregative Escherichia coli in infants with acute diarrhea based on biofilm production in Manipal, south India. Indian Journal of Medical Sciences 62(1): 8, 2008

Enteroaggregative Escherichia coli strain in a novel weaned mouse model: exacerbation by malnutrition, biofilm as a virulence factor and treatment by nitazoxanide. Journal of Medical Microbiology 62(Pt 6): 896-905, 2013