Use of Predatory Prokaryotes to Control Drug-Resistant Bacteria and Microbial Biofilms Associated with Burn and Wound Infections

Disease-causing microorganisms that have become resistant to drug therapy are an increasing cause of burns and wound infections. Bdellovibrio and Micavibrio are Gram-negative obligatory predators that feed on other Gram-negative bacteria. The focus of the study was to evaluate the potential application of predatory bacteria (Pb) to control human pathogens most associated with war-related infections. Our findings demonstrated that Pb are able to attack many of the pathogens tested, including bacteria from the genus Acinetobacter, Aeromonas, Aggregatibacter, Bordetella, Burkholderia, Citrobacter, Eikenella, Enterobacter, Escherichia, Klebsiella, Listonella, Morganella, Proteus, Pseudomonas, Salmonella, Serratia, Shigella, Vibrio, and Yersinia. Pb were also able to attack A. baumannii drug resistant clinical isolates obtained from Wounded Warriors. Positive predation was measured in single and multi-species microbial cultures as well as on monolayer and multilayer pre-formed biofilms grown in static and flow cell systems. The predators were also able to inhibit biofilm formation and remove metabolically inactive biofilms. Bdellovibrio and Micavibrio were shown to prey at 37 deg C but were unable to prey under oxygen limiting conditions. Our study also established that applying biofilm EPS (extracellular polymeric substance) degrading enzymes, with the Bdellovibrio, could enhance the biofilm removal aptitude of the predators. In conclusion, the work presented here highlights the potential use of predatory bacteria as biological based agent for eradicating infection and will pave the way for future studies in animal and human subjects.
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