They were detected in 30.5% (33/108) of DAEC strains isolated from children. We observed serogroups O86, O158, O142 and O127. Serogroup O86 was found most frequently, both in diarrhea and control strains (Table 4). Distribution of genotypic and phenotypic characteristics was similar in DAEC strains belonging to both EPEC and non-EPEC serogroups. Serogroups associated

to EPEC were not detected in strains isolated from adults. Table 4 Classical EPEC serogroups found in DAEC possessing Afa/Dr genes isolated from children Serogroups O86 O127 O142 O158 Non-EPEC     N (%) Total Diarrhea 13 (26) 0 1 (2) 5 (10) 31 (62) 50 Control 7 (12) 2 (3.4) 0 5 (8.6) 44 (75.8) 58 Total 20 (18.5) 2 (1.8) 1 (0.9) 10 (9.2) 75 (69.5) 108 Biofilms Most DAEC strains were not able to form biofilms as CFTRinh-172 research buy pure cultures. Tests carried out with

DAEC strains isolated from children showed that 88.9% (96/108) of them were unable to form biofilms under the studied conditions; 11% (12/108) formed weak biofilms (Figure 1A). The frequency of strains from children that form biofilms was greater (P < 0.01) in control (18.9% - 11/58) than in cases of diarrhea (2% - 1/50). Figure 1 Effect of interaction DAEC - C. freundii in NVP-BSK805 biofilm formation. Biofilm formation by monocultures of DAEC isolated from children (A) and adults (C); Increase in biofilm formation in DAEC-C. freundii cocultures (B, D). Comparison between the synergistic effect of cocultivation of DAEC strains recovered from children and PTK6 adults and an enteroaggregative

strain of Citrobacter freundii is shown in E. The increase in intensity of biofilm SB202190 research buy formed was higher in consortia involving strains from children. Tests performed with DAEC strains isolated from adults showed that 73.8% (31/42) did not form biofilms. Eleven strains (26.2%) formed biofilms (Figure 1C). The frequency of biofilm formation did not differ between cases (25.9% – 7/27) and control (26.6% – 4/15) strains. The frequency of DAEC strains able to form biofilms was greater (P < 0.05) among strains isolated from adults (26.2% – 11/42) than from children (11% – 12/108). Mixed biofilms In order to evaluate the effect of bacterial combinations on biofilm formation, mixed biofilm assays were conducted using cocultures of DAEC and C. freundii strain Cf 205, which forms weak biofilms when in monoculture. Mixed biofilm formation was observed in 83% (90/108) of consortia involving strains from children. In 30% (27/90) of consortia, weak biofilms were formed, while 70% (63/90) of cocultures formed strong biofilms, indicating a synergistic effect of the DAEC- C. freundii association (Figure 1B). Strong biofilms were more frequent (P < 0.05) in consortia involving strains from asymptomatic children (67.2% – 39/58) than in those involving cases of diarrhea (48% – 24/50). Biofilm formation was observed in 80.9% (34/42) of consortia involving strains from adults. Twenty-three consortia (67.