Biofilm Formation Plays a Role in the Formation of Multidrug-Resistant Escherichia coli Toward Nutrients in Microcosm Experiments

Abstract

In this study, microcosms were established to determine the effect of nitrogen (N) and phosphorus (P) on the multidrug resistance and biofilm-forming abilities of <i>Escherichia coli</i>. The expression of biofilm-formation-related genes was detected to establish correlations between genotype and phenotype. Different concentrations of N and P were added to make one control group and four treatment groups. The glass tube method was used to determine biofilm-forming capabilities. Real-time PCR was used to detect the mRNA abundance of six biofilm-formation-related genes in <i>E</i>. <i>coli</i>. No resistant strains were isolated from the control group; meanwhile, multidrug resistance rates were high in the treatment groups. Expression of the biofilm-associated genes <i>luxS, flhD, fliA, motA</i>, and <i>fimH</i> was detected in all treatment groups; however, there was no expression of <i>mqsR</i>. The expression of <i>luxS, flhD, fliA, motA</i>, and <i>fimH</i> significantly correlated with the concentration of N and P, as well as with the appearance and duration of multidrug resistance in different groups. Overall, the results of this study suggest that biofilm-forming ability plays a key role in the formation of multidrug resistance in <i>E</i>. <i>coli</i> after the addition of N and P to a microcosm.