Influence of subinhibitory concentrations of brodimoprim and trimethoprim on the adhesiveness, hydrophobicity, hemagglutination and motility of escherichia coli

In the present study the ability of subinhibitory concentrations (sub-MICs) of brodimoprim (a new 2,4-dimethoxybenzylpyri-midine) to interfere with some important aspects of bacterial cell function, such as surface hydrophobicity, fimbriation, motility and adhesiveness to mucosal cells, was investigated in comparison with those of trimethoprim. The inhibitory behavior of both diaminopyrimidines concerning hydrophobicity and hemagglutination (fimbriation) were essentially the same, while for adhesiveness and motility brodimoprim was more effective than trimethoprim. Diaminopyrimidines have high affinity for the bacterial enzyme dihydrofolate reductase, and this reduces the synthesis of essential purines and as a conse-quence of DNA and proteins. Our findings indicate that the synthesis and/or the expression of surface adhesins, which are proteins, was also affected by both brodimoprim and trimethoprim, the former being more active.