Effect of Predator Bacteria Bdellovibrio bacteriovorus on Clinical Pathogens and Biofilms

Antimicrobial resistance has become one of the most important public health problems of our century. In addition to the spread of resistance, biofilm production also makes the treatment of infections increasingly difficult. Therefore, this study, it was aimed to investigate the effect of the predator bacterium Bdellovibrio bacteriovorus HD100 on various clinical pathogens and their biofilms. A large panel of Gram-positive and negative clinical isolates were included in the study. The double-layer agar method was used to optimize the cultivation of predatory bacteria. The effectiveness of Bdellovibrio bacteriovorus HD 100 on planktonic cells and biofilms, was determined by co-culture and crystal violet staining methods, respectively. The antibiofilm activity was also visualized via scanning electron microscopy. The predator bacteria was found effective against most of the Gram-negative isolates. But it was determined that the lowest activity among these isolates was shown to Pseudomonas aeruginosa and Acinetobacter baumannii. Although it is known that B. bacteriovorus does not predate on Gram-positive isolates, interestingly, Staphylococci species included in this study were found to be inhibited in co-culture studies. As determined in co-culture and biofilm studies, B. bacteriovorus can be used to control both bacterial growth and biofilms in most Gram-negative species. Interestingly, our data also suggest that predatory bacteria may also be effective against Gram-positive bacterial biofilms in addition to Staphylococcus aureus. Although the evaluation of different species of isolates in this study demonstrates the potential of predatory bacteria, the host specificity and the relation of prey and predator need to be demonstrated.