Atypical EnteropathogenicEscherichia coliStrains form Biofilm on Abiotic Surfaces Regardless of Their Adherence Pattern on Cultured Epithelial Cells

Abstract

The aim of this study was to determine the capacity of biofilm formation of atypical enteropathogenic Escherichia coli (aEPEC) strains on abiotic and biotic surfaces. Ninety-one aEPEC strains, isolated from feces of children with diarrhea, were analyzed by the crystal violet (CV) assay on an abiotic surface after 24 h of incubation. aEPEC strains representing each HEp-2 cell type of adherence were analyzed after 24 h and 6, 12, and 18 days of incubation at 37°C on abiotic and cell surfaces by CFU/cm2 counting and confocal laser scanning microscopy (CLSM). Biofilm formation on abiotic surfaces occurred in 55 (60.4%) of the aEPEC strains. There was no significant difference in biofilm biomass formation on an abiotic versus prefixed cell surface. The biofilms could be visualized by CLSM at various developmental stages. aEPEC strains are able to form biofilm on an abiotic surface with no association with their adherence pattern on HEp-2 cells with the exception of the strains expressing UND (undetermined adherence). This study revealed the capacity of adhesion and biofilm formation by aEPEC strains on abiotic and biotic surfaces, possibly playing a role in pathogenesis, mainly in cases of persistent diarrhea.

Antibiotic resistance and biofilm formation in children with Enteropathogenic Escherichia coli (EPEC) in Brazilian Amazon

“…Adherence patterns in HEp-2 cells due to biofilm production were observed in the present study; but, there was no association among the three adhesion profiles -this outcome is consistent with the study by Culler et al [26]. These authors showed the ability of aEPEC strains to adhere to, and to form biofilm on, abiotic surfaces (55 isolates -60.4%); however, there was no association between the four adherence patterns and biofilm formation.…”

“…The ability of EPEC isolates to form biofilm was observed in 33.8% (24/71) of isolates assessed in the present study; therefore, they are an additional virulence factor and a natural resistance mechanism in bacteria [8,26]. Biolfim is also related to bacterial persistence in infection cases, because the exopolysaccharide matrix formed in the biofilm avoids the penetration of antimicrobial agents and hinders bacterial destruction in the biofilm [32,33].…”

“…LAL adherence pattern was observed in 59.3% (35/59) of aEPEC isolates after 6-hour incubation. Many authors have reported that LAL is the most frequent among aEPEC strains; however, several adherence profiles (DA, AA, LA and LAL) were described due to aEPEC heterogeneity [24,26]. Pitondo-Silva et al conducted a study in São Paulo (Brazil) with 60 EPEC isolates; they found 18 aEPEC isolates that presented LAL pattern in the HEp-2 cells assay [15].…”

Vancomycin and maltodextrin affect structure and activity of Staphylococcus aureus biofilms

“…In our case, we tested this effect for already developed mature biofilm; it may be more significant in initially developing biofilms, because of the inoculum effect (Corrado et al, ; Li and Ma, ; Rose et al, ). Young biofilms grown for 24 h can have 7–8 logs of CFU (Amorena et al, ; Barraud et al, ; Culler et al, ; Freitas et al, ). The more maltodextrin is present in the medium, the higher the osmolality of the solution will be (Rong et al, ).…”

Diarrheagenic Escherichia coli

“…Atypical EPEC strains have also been shown to adhere to abiotic surfaces (polystyrene and glass) 94, 95. The non-fimbrial adhesin curli and the T1P have been shown to mediate binding to these surfaces in some aEPEC at different temperatures 90, 96…”