Myxobacteria Are Able to Prey Broadly upon Clinically-Relevant Pathogens, Exhibiting a Prey Range Which Cannot Be Explained by Phylogeny

Abstract

Myxobacteria are natural predators of microorganisms and the subjects of concerted efforts to identify novel antimicrobial compounds. Myxobacterial predatory activity seems to require more than just the possession of specific antimicrobial metabolites. Thus a holistic approach to studying predation promises novel insights into antimicrobial action. Here, we report the isolation of 113 myxobacteria from samples of soil taken from a range of habitats in mid Wales. Predatory activity of each isolate was quantified against a panel of clinically important prey organisms, including Klebsiella pneumoniae, Proteus mirabilis, Candida albicans, Enterococcus faecalis, and three species of Staphylococcus. Myxobacterial isolates exhibited a wide range of predation activity profiles against the panel of prey. Efficient predation of all prey by isolates within the collection was observed, with K. pneumoniae and C. albicans proving particularly susceptible to myxobacterial predation. Notably efficient predators tended to be proficient at predating multiple prey organisms, suggesting they possess gene(s) encoding a broad range killing activity. However, predatory activity was not congruent with phylogeny, suggesting prey range is subject to relatively rapid specialization, potentially involving lateral gene transfer. The broad but patchy prey ranges observed for natural myxobacterial isolates also implies multiple (potentially overlapping) genetic determinants are responsible for dictating predatory activity.

The Predation Strategy of Myxococcus xanthus

“…Compared to other bacterial predators, which display a limited prey spectrum, M. xanthus is a generalist that is able to feed on a broad range of bacteria and some fungi: It has been observed to prey on soil bacteria (Rosenberg and Varon, 1984;Morgan et al, 2010;Mendes-Soares and Velicer, 2013), including plant pathogens (Pham et al, 2005), on cyanobacteria (Shilo, 1970), clinically relevant species, such as Pseudomonas aeruginosa and Staphylococcus aureus (Müller et al, 2014;Livingstone et al, 2017), yeasts (Berleman et al, 2006;Livingstone et al, 2017), and other fungi (Bull et al, 2002). Comparative analysis of predation performance indicates that, under laboratory conditions, most prey species significantly support M. xanthus growth (Morgan et al, 2010;Mendes-Soares and Velicer, 2013;Livingstone et al, 2017). Considering the broad spectrum of prey that can be utilized by M. xanthus, it is likely that different molecular mechanisms, acting either in isolation or synergistically, are required to prey on different species.…”

Culture-dependent and -independent methods revealed an abundant myxobacterial community shaped by other bacteria and pH in Dinghushan acidic soils

“…Additionally, as social predators, myxobacteria exhibited a wide range of predation activities against both bacteria and fungi [ 13 , 14 ], changing the structure and diversity of microbial community [ 15 , 16 ]. Moreover, Wang et al .…”

Bacillus licheniformis escapes from Myxococcus xanthus predation by deactivating myxovirescin A through enzymatic glucosylation

“…Myxobacteria are a group of ubiquitous, soil-dwelling and gram-negative bacteria with complex social lives and multicellular developmental cycles, that is, surface motility, fruiting body formation, sporulation and especially predatory behaviour (Dawid, 2000;Muñoz-Dorado et al, 2016;Wrótniak-Drzewiecka et al, 2016). As natural predators of microorganisms, myxobacteria are one of the most common and diverse groups of bacteria that exhibit a broad prey range of both soil bacteria and clinically important pathogens, suggesting that they have significant ecological and evolutionary impacts on their prey (Morgan et al, 2010;Findlay, 2016;Livingstone et al, 2017). Due to its genetic tractability, the best-studied myxobacterium is Myxococcus xanthus, which is able to hunt prey cells using a group attack strategy that is typically described as a 'wolfpack' (Berleman and Kirby, 2009).…”