RESUMO
BACKGROUND/AIM: To detect the effects on quinolone resistance due to biofilm formation activity in Ureaplasma urealyticum. MATERIALS AND METHODS: An improved checkerboard dilution susceptibility test was used to analyze the quinolone resistance of clinical Ureaplasma isolates and a postbiofilm formation susceptibility assay was used to compare the effects on the quinolone susceptibility between pre- and postbiofilm formations. Several important functional gene expressions were detected to evaluate their roles in the process of the quinolone resistance mechanism. RESULTS: The quinolone-resistant isolates produced more biofilms than the sensitive isolates. In both the quinolone-resistant and -sensitive groups, the minimal inhibitory concentrations after biofilm formation were higher than those before biofilm formation. The expression of the metabolism-related gene ureC in postbiofilm formation was higher than those in prebiofilm formation. CONCLUSION: It seems that biofilm formation is quite important in the generation of quinolone resistance in Ureaplasma. It is very useful to detect biofilm formation activity as well as to analyze other laboratory parameters for Ureaplasma.