Data from: Biofilm inhibition and pathogenicity attenuation in bacteria by Proteus mirabilis

Biofilms play an important role in the antibiotic resistance of encased
bacteria, and their formation was regulated by quorum sensing (QS).
Inhibiting the QS system may therefore degrade the integrity of a biofilm
and expose the bacterial pathogens within it to the deleterious effects of
molecules such as antibiotics. Moreover, the use of QS inhibitors (QSIs)
may provide a novel approach for treating bacterial infections of
aquacultures. In the present study, the bacterium Proteus mirabilis was
identified as a potential producer of QSIs. Varying concentrations
(0.1-1.1%) of filtrates prepared from the culture of P. mirabilis
inhibited biofilm formation by the pathogens Pseudomonas aeruginosa,
Vibrio harveyi, and Staphylococcus aureus by as much as 58.9%, 41.5%, and
41.9%, respectively. These filtrates as well as the crude aqueous extracts
prepared from them increased the sensitivities of pathogens to the
inhibitory effects of kanamycin. The filtrates also showed pathogenicity
attenuation potential in P. aeruginosa by decreasing the production of
virulence factors. Moreover, the filtrates did not influence the
planktonic growth of these pathogens. The results indicate that P.
mirabilis may act as a nonspecific (or broad-spectrum) inhibitor of
biofilm formation that will help control infectious diseases that
adversely affect the aquaculture industry.