Open AccessAssociation of Putative Enteroaggregative Escherichia coli Virulence Genes and Biofilm Production in Isolates from Travelers to Developing Countries
Author(s) -
Jamal A. Mohamed,
David B. Huang,
Zhi Jiang,
Herbert L. DuPont,
James P. Nataro,
Jaime BelkindGerson,
Pablo C. Okhuysen
Publication year - 2007
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.01128-06
Subject(s) - enteroaggregative escherichia coli , virulence , biofilm , microbiology and biotechnology , diarrhea , biology , pathogen , escherichia coli , virology , enterobacteriaceae , gene , bacteria , medicine , genetics
EnteroaggregativeEscherichia coli (EAEC) is an emerging enteric pathogen that causes acute and chronic diarrhea among children, human immunodeficiency virus-infected patients, and travelers to developing regions of the world. The pathogenesis of EAEC strains involves the production of biofilm. In this study, we determined the association between presence of putative EAEC virulence genes and biofilm formation in 57 EAEC isolates (as defined by HEp-2 adherence) from travelers with diarrhea and in 18 EAEC isolates from travelers without diarrhea. Twelve nondiarrheagenicE. coli isolates from healthy travelers were used as controls. Biofilm formation was measured by using a microtiter plate assay with the crystal violet staining method, and the presence of the putative EAEC virulence genesaap ,aatA ,aggR ,astA ,irp2 ,pet ,set1A , andshf was determined by PCR. EAEC isolates were more likely to produce biofilm than nondiarrheagenicE. coli isolates (P = 0.027), and the production of biofilm was associated with the virulence genesaggR ,set1A ,aatA , andirp2 , which were found in 16 (40%), 17 (43%), 10 (25%), and 27 (68%) of the biofilm producers versus only 4 (11%), 6 (6%), 2 (6%), and 15 (43%) in non-biofilm producers (P = 0.008 foraggR ,P = 0.0004 forset1A ,P = 0.029 foraatA , andP = 0.04 forirp2 ). Although the proportion of EAEC isolates producing biofilm in patients with diarrhea (51%) was similar to that in patients without diarrhea (61%), biofilm production was related to the carriage ofaggR (P = 0.015),set1A (P = 0.001), andaatA (P = 0.025). SinceaggR is a master regulator of EAEC, the presence ofaap (P = 0.004),astA (P = 0.001),irp2 (P = 0.0006),pet (P = 0.002), andset1A (P = 0.014) in anaggR versus anaggR -lacking background was investigated and was also found to be associated with biofilm production. This study suggests that biofilm formation is a common phenomenon among EAEC isolates derived from travelers with or without diarrhea and that multiple genes associated with biofilm formation are regulated byaggR .