Quantitative biofilm assay using a microtiter plate to screen for enteroaggregative Escherichia coli.
The gold standard for identification of Enteroaggregative Escherichia coli (EAEC) remains the HEp-2 cell adherence test, which is time-consuming and requires specialized facilities. We evaluated the usefulness of a quantitative biofilm assay to screen for EAEC from a total of 1,042 E. coli strains from children with diarrhea. Bacteria were incubated overnight in high-glucose Dulbecco's modified Eagle's medium using a polystyrene microtiter plate. The plate was stained with crystal violet after washing, and the biofilm was quantified using an enzyme-linked immunosorbent assay plate reader. The aggR gene was evaluated by a polymerase chain reaction. Forty-eight (77.4%) of 62 strains with an optical density at 570 nm (OD(570)) > 0.2 were identified as EAEC by the HEp-2 adherence test, while no EAEC was found in strains with an OD(570) < or = 0.2. Twenty-one aggR+ and 27 aggR - EAEC strains could be screened by an OD(570) > 0.2 using this assay. Although confirmation by a HEp-2 cell adherence test is needed, this biofilm assay is convenient and useful in screening for EAEC.
Wakimoto
Naoko
N
Department of Pediatrics, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan.
Nishi
Junichiro
J
Sheikh
Jalaluddin
J
Nataro
James P
JP
Sarantuya
Jav
J
Iwashita
Mayumi
M
Manago
Kunihiro
K
Tokuda
Koichi
K
Yoshinaga
Masao
M
Kawano
Yoshifumi
Y
D018441:Biofilms; D002648:Child; D015169:Colony Count, Microbial; D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis; D003967:Diarrhea / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000382:microbiology; D004926:Escherichia coli / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests
D017931:DNA Primers; D004269:DNA, Bacterial