Bacterial predatory potentials of indigenous Bdellovibrio species in southwest Nigeria: Targeting multidrug-resistant Klebsiella pneumoniae and Enterobacter species isolated from chronic wound infections

Background: Chronic wound infections could become life-threatening conditions when caused by multi-drug-resistant Gram-negative ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp) pathogens. Alternative therapeutic approaches are vital for the therapy of infections caused by these pathogens and one of the biocontrol therapies is the application of Bdellovibrio spp, a Gram-negative bacterium with predatory potential against pathogenic Gram-negative bacteria.Methodology: This study isolated, and phenotypically and genotypically characterized Bdellovibrio spp from environmental sources including soil, pond waters, and faecal materials from cattle and poultry in Osogbo, southwest Nigeria using double-layered agar plating technique, with Klebsiella spp as prey. The prey range and predatory potentials of the isolated Bdellovibrio spp against 25 clinical bacterial isolates including 6 K. pneumoniae and 19 Enterobacter spp, recovered from chronic wound infections, was assessed using the same double-layered agar technique.Results: Five strains of Bdellovibrio isolated formed characteristic plaques on lawns of Klebsiella spp used as prey. At the molecular level, all the five strains, designated UAB, STU, PW2, PW5, and PW6, belonged to the genus Bdellovibrio, however, they exhibited different clustering patterns on the phylogenetic tree. Additionally, the prey range of the five Bdellovibrio strains on the bacterial isolates varied, with UAB, PW6, PW5, and PW2 preying upon 12 (48.0%), 12 (48.0%), 7 (28.0%), and 1 (4.0%) bacterial isolate respectively, while STU did not prey on any of the bacteria isolates.Conclusion: This research presents the first molecular characterization of Bdellovibrio spp in Nigeria, hence serving as a baseline study for future Bdellovibrio research in Nigeria. It also highlights the promising potential of Bdellovibrio spp in control of K. pneumoniae and Enterobacter spp associated with chronic wound infections.